swilburnwx

[swilburnwx]

Nashville, TN

3/31/2018   11:00pm

The past week has been full of wish-forecasting and wondering if severe weather will actually happen. This coming week pales in comparison to the excitement of the storms that hit the south this past Wednesday. For Nashville, the biggest story is rain.

Nashville has a pretty mild week ahead. After an Easter Sunday filled with rain and clouds, some might wish that the sun comes out, but it does not look too likely right now. On Monday, the clouds and rain stick around for the majority of the day. Portions of Tennessee, including Nashville, could see some showers from the leftover moisture from Sunday’s rain, and because dewpoints are close to the air temperature. Monday night tells the same story with a chance of rain and more clouds.

Tuesday night has the highest chance of rain. As an area of low pressure pushes across the US, it looks like it will strengthen a bit before affecting Nashville. I do not think there will be too high of a chance of severe weather since the center of the low seems to be following a track through Missouri towards the Great Lakes (some ways away from Nashville), so the greatest threat is rain and potentially some localized flash flooding.

For Wednesday into Thursday, a high pressure builds in behind the little trough and the skies will finally clear and the sun can shine. With the cooler air entering Nashville, the temperatures will drop from the 70s week to the upper 40s and low 50s for the rest of the week. Luckily, the sun will be out to warm things up just a bit, so it shouldn’t feel too terrible outside.

Friday the clouds come back, most likely due to the dewpoints being relatively close to the air temperature. A slight southerly flow could also be bringing in some low-level moisture from the Gulf of Mexico that would cause some low-level clouds to from throughout the day. As the hours go on, more and more clouds will form ahead of another trough making its way into Tennessee.

Saturday, another area of low pressure moves into the eastern US, bringing yet another chance of rain to Nashville. This trough is nowhere near as strong as the low from Wednesday, but it does have just enough energy and dry air behind it to cause some convection and rain ahead of the front. All in all, Nashville has a pretty boring and dreary week ahead with lots of rain and clouds. A break in the middle of the week will allow people to recharge with some sun before another round of rain at the start of the weekend. 

[swilburnwx]

Pueblo, CO

3/24/2018    6:30pm

Pueblo, CO seems like a nice, quiet city in the Rocky Mountains where not much should happen (of course, no place on Earth exists where weather doesn’t happen). While it is not really ever in the news like big cities, some interesting things are happening there this weekend.

There is only one thing to notice on this 12z sounding: Pueblo is incredibly DRY. The only hint of moisture on this sounding from the morning is right at the surface, but the rest of the troposphere is incredibly dry. Dewpoints are currently sitting in the teens to lower 20s throughout much of the western US with no to little chance of rain in the near future. Pair this with the winds, and we have a huge fire hazard.

Temperatures in the southwest have been pretty warm recently. This weekend, Pueblo will see highs in the mid 70s, and being outside should feel pretty nice! As the weekend wraps up and Monday rolls around, a shortwave trough pushes into the US, bringing cooler and drier air behind it. While this weekend has felt warm, the rest of the week will cool off slightly.

When talking about fire weather and fire potential, it is always important to talk about the winds. Dry air and warm temperatures create a good environment for a fire to grow rapidly, but the wind is what causes the fire to spread and become out of control. This weekend, namely Sunday, sustained winds start off around 8mph. By the afternoon, the winds increase to around 20mph. When sustained winds are around 20mph, gusts of winds could be much faster. Strong gusts plus already pretty strong sustained winds creates an ideal setting for any fires to spread quickly.

With warm temperatures, windy conditions, and low dewpoints, the NWS has placed southern CO and a large part of New Mexico under critical and elevated fire weather conditions, respectively. The outlook for Sunday places the entire region under critical fire conditions, indicating conditions are going to get worse before they get better. Colorado and much of the Southwest is currently battling a drought. The lack of precipitation greatly intensifies any dry and fire-prone conditions in many places out west, and even in GA. So will CO see rain anytime soon?

The only sign of relief would be an approaching shortwave trough that will make its way across the west on Monday, but even then the chance of precipitation for southern CO is low. Once the trough pushes through, more dry air will enter the region. In front of the shortwave, the southeastern corner of CO is forecasted to receive some precipitation, which could be enough to raise the dewpoint. Fire conditions should lessen with the arrival of this wave, mainly because the small bit of added moisture and cooler temperatures will not create such a dry environment. If the temperatures are cooler and there is even the slightest bit of moisture, the relative humidity increases and the chance of fires decreases.

Overall, Pueblo has an interesting Sunday ahead in terms of potential fires, but the incoming shortwave trough will bring cooler temperatures and will diminish the fire threat for the next week. 

[swilburnwx]

Gulf Shores, AL Spring Break (again)

March 8, 2018  2:30pm

Spring break is so close, but the warm temperatures aren’t. Here’s another look at the Gulf Coast next week.

Looking at the overall system moving through the SE compared to my previous blog post, the models have slowed down the system. Last time, the system was already over Gulf Shores at 18z on Saturday, but the most recent model run shows that the bulk of the rain does not reach Gulf Shores until 06z Sunday. The system is moving slower than originally predicted. It also does not look as severe for southern Alabama as my previous blog post. Today, it looks like the rain will last from late Saturday night into Sunday evening, unfortunately causing two days of less-than-favorable beach weather. After that, the center of the system moves off the east coast and looks like it will be the next Nor’easter that pummels the Northeast. As for Gulf Shores, it should stat dry and as that cooler and drier air moves into the area.

I’m beginning to hate looking at the temperatures for spring break because it just makes me sad. The newest model run honestly looks like the temperatures will be cooler on the beach than what I previously thought. 18z Monday only shows a temperature in the low 50s, indicating the daytime high might not be too much warmer than that. Temps might reach 53-55 degrees that day, but unless the models are 100% wrong, it will not be very warm. As the week goes on, the highs increase into the low 60s, then the mid 60s, but the temperatures for beach goers won’t reach the 70s until Friday. Another thing to think about with respect to the beach is the sea breeze. It is always cooler on the beach than farther inland thanks to the sea breeze and the water influence. If the highs are only in the mid 60s, the beach will feel cooler (more low 60s, or even upper 50s). It is going to be chilly.

Because it rains pretty often in Gulf Shores, I wanted to look at MOS to see what the probability of precipitation is. I also wanted to peek at the temperatures and see how they compare to the model temperatures. Gulf Shores does not have its own site, so I chose to look at Mobile, AL. The temperatures and precip chances will, of course, be slightly different, but it should be close enough to estimate. Looking at Saturday into Sunday (when the rain is supposed to hit), the precipitation chances aren’t super high. The 12-hour probability at 12z on Sunday only states a 75% chance of rain. The impressive prediction is that the 24-hour probability states a 92% chance of rain. Essentially, there will definitely be rain Sunday morning. After that, the rest of the week looks clear with low precip probabilities and clear skies.

Temperature wise, things look gloomy. Sure, Sunday looks like it will see a high of 76, but the temps plummet the next day. Monday will be chilly, especially for beach goers. 58 degrees and a sea breeze does not make for good spring break weather. The temps warm up just slightly by the end of the week, but (of course), don’t make it back into the 70s until the end of break.

Despite the cold temperatures for the beach, the skies will be clear. I know people will still brave the breeze to get a tan, so it is important to look at the UV index for next week. Unfortunately, the predicted UV index only reaches Monday, but the actual index value should not vary too much. For Gulf Shores, the UV index is 7, suggesting the sun will still be potentially dangerous during break. Personally, I think it’s funny how many people will be freezing, but still frying. A UV index of 7 means everyone should still apply sunscreen of at least SPF 30 every 2 hours, regardless of whether it is cold or not. Another big thing to remember is that the sand reflect the sun, increasing the chances of burning, and you can still get burnt with a cloudy sky.

[swilburnwx]

Spring Break on the AL/FL Gulf Coast

March 3, 2018   8:00pm

There is only one more week of classes before spring break, and the temperatures don’t seem too welcoming for a beach trip. Will the temperatures warm up before spring break is in full swing?

The NAO is on the upswing (thankfully), meaning a positive phase is on the way. According to both the overall ensemble and the ECMWF ensemble, it is going to take a little while for the NAO to enter a positive phase. However, since the NAO is becoming less negative, the pressure over Iceland will weaken. Less troughs will back up over the east coast and warmer temperatures. For spring break, the NAO stays negative during the whole week, but this doesn’t mean that temperatures will remain cold. As it becomes more positive, there is a greater chance of warmer temperatures since less troughs will pile up behind the pressure in Iceland.

Similar to the NAO, the AO is on the way to a positive phase. For spring break, the AO also doesn’t reach a completely positive phase, but as it weakens, there is less of a chance of arctic air making its way south. For any beachgoers, temperatures may not be as warm as you want, especially at the beginning of the week where the AO takes a slight tip towards a more negative state. Towards the end of the week, the AO reaches its most positive state around the same time the NAO becomes more positive. The combination of these two teleconnections becoming more positive is hope that spring break will be warmer than this past weekend.

The MJO is always a good teleconnection to reference in terms of convection and the chance of cooler weather. When the MJO is in phases 1 and 2, temperatures are typically cooler than average for the AL/FL Gulf Coast (and much of the US). On the bright side, when the convective branch of the MJO is over the Indian Ocean, so is the greatest chance of enhanced convection. As the MJO continues to move eastward, during spring break, the chance of enhanced convection and precipitation lessens, so we should see more sun towards the end of the week.

In terms of temperatures during the week, the beginning of spring break is looking a little chilly. Not only are the temperatures in the low 60s for the beginning of the week, but the sea breeze will make things feel even cooler. On Monday, the high only reaches 50 degrees. Thankfully, temperatures rise later on in the week--the same time the NAO and AO become more positive. By the end of break, beach temperatures should reach back into the 70s with plenty of sun.

The cooler temperatures are most likely due to this shortwave trough making its way across the eastern US during the beginning of next week. As the low approaches FL on Saturday, an area of moisture fuses with the precipitation more north and will most likely bring rain to the Gulf Coast beaches. Throughout Sunday and Monday, the trough continues to propagate eastward, bringing more showers during the day. Once this little low moves off the coast, a ridge settles in over the east and the sun should reappear and temperatures will be warmer.

All in all, the weather conditions for the beginning of spring break are not the best, but the second half of the week should be really nice for anyone spending their time at the beach. Hopefully, the only thing to worry about once the rain moves on is reapplying sunscreen! 

[swilburnwx]

Starkville Saturday Night

Feb. 24, 2018   3:00pm

Since we have been covering this event for the majority of the week, I wanted to look at some of the models and see if anything has changed.

Since yesterday, the latest GFS run shows the low pressure still tracking northeast towards the Great Lakes. The main difference is that the low is weaker, and the low is tracking slightly more west than previously thought. Another difference that I noticed from SPC is that the system is moving slower than we thought at the beginning of the week. The system was originally thought to hit Starkville around midnight, but now SPC has estimated Starkville’s greatest chance of rain and severe weather will be from 1-6am.

The sounding for Starkville isn’t too impressive in terms of CAPE. According to the GFS soundings above, there is almost no CAPE around midnight. We can still see that dry pocket around 800mb that is contributing to our wind threat, but the overall sounding is not what we want for sever weather. Looking at the hodograph, we can see that we don’t have the southeasterly flow, which we noticed yesterday.

In terms of instability, the cloud cover was not as thick as we thought it might be during today. The sun was out in the morning and through the afternoon, heating the surface and increasing the instability of the lower atmosphere. Once the front moves through, there will be plenty of heat and moisture to create storms and rain. Essentially, there is no question whether we will get rain or storms tonight—it is a given and has been a given for a while. But seeing the sun so much today will definitely help the chance of severe weather.

The winds tonight will be an interesting aspect of this front. While we will see some thunderstorms and heavy rain, one of the main threats for tonight is winds. The GFS sounding for tonight 2am show winds anywhere from 35-40mph, which could cause some downed tree limbs. Another threat for tonight, especially during period of heavy rainfall, is flash flooding. Starkville road do not handle rain very well, so anyone driving early in the morning should use extra caution.

GFS

NAM

By the end of the weekend, Starkville will have accumulated around 1.5” of rain. SPC says there is a 50% chance of storms/rain tomorrow but looking at the forecasted soundings from both NAM and GFS, dry air starts invading the midlevels on Sunday morning, pretty much eliminating chances of rain for the rest of the day. However, the Sunday night soundings show another round of rain for Starkville. It is going to be a wet weekend, but luckily since this front wasn’t associated with a strong trough (just a shortwave trough), temperatures will stick to spring temperatures in the upper 60s, and I’m pretty happy about that!

[swilburnwx]

Southern Hemisphere Tropical Discussion

2/17/2018   10:45pm

Things in the northern hemisphere have been mild during the winter months. In the southern hemisphere, the tropical season has been a bit more interesting.

The global tropics hazards and benefits outlook is interesting: the next three days look relatively active, but next seems like it will be quiet. The main reason for the enhanced activity in the southern hemisphere is the phase and location of the MJO. Australia looks like it should have seen a lot of activity (which is absolutely true with a tropical cyclone, tropical storm, and invest area currently surrounding the continent). For next week, the main concern is below average rainfall, most likely due to the MJO moving out of the Maritime Continent and towards North America.

Looking at SST anomalies in the southern hemisphere, the overall trend is warm, but the only area that really sticks out as abnormally warm is that little spot near New Zealand. Things in the southern hemisphere should be cooling down as summer comes to an end and fall arrives. One thing that is interesting in terms of SSTs is the area of warm water in relation to the current tropical storms. Near Australia, there is a tropical cyclone, a tropical storm, and an invest area. For the cyclone and tropical storm, the SSTs are at the 26˚C threshold for tropical cyclones, but the water isn’t impressively warm. For the invest area, the water is plenty warm.

The area of invest doesn’t look too interesting in VIS imagery. Plus, there is a lot of negative shear around the area, suggesting it may not be the best area for intensification or organization. The actual storm itself is an area of interest because of the lower pressure associated with it and the enhanced precipitation and cloud cover. Unfortunately, this storm may not have exactly what it needs to become a strong cyclone.

Looking at shear on a larger scale, we can see that the shear to the north of Australia is pretty favorable for tropical cyclone development or intensification. Too bad the sinking branch of the MJO will bring below average rainfall. In terms of the direction of the flow affecting the invest area, the steering flow is not too strong. There is a bit of westward motion around the tropical storm and the invest area, but the storms won’t be moving anywhere quickly.

I know I have written this in my blogs multiple times, but it is very true. The combination of 200hPa Velocity Potential Anomalies and the 7-day Average OLR Anomalies can tell us a lot about where the MJO is and how it is behaving. The MJO has been hanging out in the Pacific region for the last week and has slowly been weakening. Looking at the velocity potential anomalies, there is a large portion of the southern hemisphere that is experiencing enhanced convection. Usually, when we see enhanced convection, we should also see areas of negative OLR anomalies, but the OLR values were all over the place in the last week. Since the MJO has also been weakening, it may not be influencing the convection as much as we might think, leading to some areas of positive OLR anomalies and other areas of negative anomalies.

Overall, the southern hemisphere definitely has not seen the same kinds of conditions we did this past summer, but there are still some interesting things happening. The main factor in everything in the southern hemisphere tropics is the MJO—it has a huge say in what will happen (not only in the southern hemisphere but also up here in North America). It will be interesting to see how this oscillation finally acts in the next couple of weeks. I’m just hoping for a warm spring break and sun!

[swilburnwx]

Harrisburg, PA

2/10/2018   6:30pm

The big weather story this weekend is the winter storm currently bringing lots of snow to the Midwest. What happens to the places ahead of this slow moving cold front?

Despite the snow storm barreling across the Midwest, PA has been relatively quiet. Right now, the temperature in Harrisburg is a bit above normal, sitting at 36˚ with 3mph northwesterly winds. Over the past couple of hours, the temperature has remained steady around 36˚-35˚ with weak to calm winds. Fog is covering most of the area with some patchy areas of rain throughout the day, as shown in the above radar.

              In terms of the forecast soundings and model outputs, there are some interesting things to note. Firstly, GFS forecasted Harrisburg to be warmer than it actually is, but the winds and the previous trend of unchanging temperature is pretty spot on. The GFS also shows rain in PA right now, but according to surface observations and the radar, there is only fog—not rain. The NAM also shows rain even though it isn’t raining, but the surface temperature and winds are much closer to the actual observations. The models are forecasting rain at 5pm, but there is only fog, which is interesting. Because the models aren’t initializing as well as they could be, the forecast soundings will most likely not show a perfectly accurate representation of what will happen with any precipitation. Because the NAM was closer to the current temp obs, I will use it for the rest of the forecast.

Tonight, the cold front makes its way into Harrisburg, bringing more rain and (eventually) drier, cooler weather. In terms of tonight, Harrisburg can expect to see surface temperatures sticking around 35˚ with actual rain, not just fog. Something interesting to note is the air temperature above the surface. At midnight, the air temp is forecasted to reach 50˚, which seems strange for a cold front making its way through the country. The reason for this is right when the front of the low pressure system reaches PA, southwesterly winds bring more moisture and warmer temperatures throughout much of the atmospheric profile. At the surface, temperatures will still be much colder, and if the temp does dip down below freezing, there could be some instances of freezing rain. For Harrisburg, freezing rain does not seem too likely.

Tomorrow will be a similar story to tonight. This front is slow and steady, which means the temperatures and rain will continue throughout the day. Highs tomorrow will reach the upper 30s to low 40s with a rain total of around 1” by 11:59pm. Sunday night into early Monday morning is when the colder temperatures begin to creep into Harrisburg. The chance of precipitation goes down with the temperatures, so any precipitation chances starting Monday morning (while slim) could result in some light snow flurries.

Monday is when the cold front rears its head and brings those cold temperatures and dry air. After the front moves through, a high pressure system sets in and brings clear skies will clear and sunshine. Highs are forecasted to sit around the mid 30s, but if the sun heats the surface enough, Harrisburg could see temps in the upper 30s. It will feel much drier outside, as shown by the sounding above. The mid levels’ dewpoint is much lower than the surface, indicating absolute 0% chance of rain and a slim chance of upper-level clouds.

Tuesday will remain the same as Monday, for the most part. The colder air settles in a bit more and highs will only reach the lows 30s at most. Rain still is not in the forecast, but as the day goes on, the air is not as dry as Monday. Some mid level clouds will form in the afternoon and the sky cover will increase into the night. The rest of the week follows the same pattern. Thursday night, GFS shows a small trough making its way into the northeast, bringing some more showers and cooler temperatures to Harrisburg. While small, the negative height anomalies are still significant, and it seems like the trough will take a while to completely leave the area.

[swilburnwx]

Teleconnection Analysis

Feb. 3, 2018    5:00pm

Instead of focusing on one spot in the US, I wanted to look at the teleconnections affecting the US and see if there is something interesting that pops up in the future.

CPC 30 Day 500-hPa Height Anomalies

Around the world, multiple teleconnections exist that affect the weather. These teleconnections can sometime work with each other to bring colder weather to an area, or can sometimes affect each other and result in something out of the ordinary. Today, I want to look at ENSO and the AO, PNA, and NAO to see if we can get a glimpse of what the next two weeks has in store.

Weekly SST Anomalies  – Jan 21-27

CPC Temperature and Precip Outlook  – February-April

Currently, ENSO is in a La Nina phase. The most recent weekly SST anomaly shows that the cold water off the coast of South America is still there, and doesn’t look to be fizzling out anytime soon. In a La Nina, flow across the US is more meridional than zonal, leading to more troughs and ridges in the jet stream. A meridional pattern does not mean the weather will be colder or warmer, it means more variability in the weather patterns (which does not make ENSO a perfect forecasting tool for whether it will be colder or warmer). The Climate Prediction Center predicts the temperature across the southern US to be warmer than average until April. Now, this doesn’t mean that everything will be warm—it could mean that we get a cold snap followed by warmer weather. 

Overall AO Ensemble  – Feb 3

ECMWF AO Ensemble  – Feb 3

The Arctic Oscillation might offer a bit more insight into the chance for cold temperatures. A negative phase of the AO indicates flow that brings colder air farther south into the US. The AO is currently in a negative phase (probably a small reason why the wind has been so brutal earlier this weekend), but the overall ensemble shows the oscillation becoming positive before plummeting two weeks from now. The Euro ensemble, though a factor of the overall ensemble, shows the AO also going positive, but it takes a much longer time for things to completely switch back to a negative phase. The first thought here is that the AO plummeting and bringing colder air does not match up up the CPC prediction of warmer temps. So what gives?

Overall PNA Ensemble  – Feb 3

ECMWF PNA Ensemble  – Feb 3

The Pacific/North American Pattern is another indicator of cold weather. This pattern describes how out of phase the west coast of the US is with the east coast. A positive phase means there is a ridge to the west (and warmer temps) while there is a trough in the east (cold temps). The general ensemble outlook shows the PNA going negative for the next two weeks, but the Euro once again shows something a little different. It shows the PNA consistently staying in a negative phase—meaning warmer temps in the east and cooler in the west. The PNA doesn’t seem like it will reach a strong positive or negative phase, but it might still impact the weather patterns.

Overall NAO Ensemble  – Feb 3

ECMWF NAO Ensemble  – Feb 3 

The North Atlantic Oscillation is  teleconnection that is calculated based on pressure ratios between Iceland and Portugal. This teleconnection is where the phrase “Greenland Blocking” becomes most important. In a positive phase, an area of low pressure is over Iceland with little/no Greenland locking, meaning troughs and ridges don’t stall in the US, they can move right across the globe. If the NAO goes negative and a strong trough comes through the US, it might stall in the east for a bit, bringing colder temperatures that might last longer than desired. The overall ensemble looks like we will stick in the positive phase according to the ensembles, meaning maybe slightly more variability and less chance of a deep trough wreaking havoc for the east coast. The Euro is one of the members forecasting a positive phase for the next two weeks. There is one ensemble member that shows the NAO plummeting into a negative phase two weeks from now, which is interesting.  

500mb Height Anomalies  – 12z Feb 3-00z Feb 14

So, with all of the teleconnections, does this all make sense?  According to the GFS 500mb Height anomalies, there don’t look like there are too many super strong ridges or troughs coming through the US until the end of the run. Something interesting to note is that the end of the above gif is when all of the oscillations begin to make their forecasted switch towards or into the opposite phase.  It looks like there will be a few more chances for cold weather in the southern US throughout the next two weeks. If we have a trough in the east with a chance for much colder air AND a negative NAO, we might be in for some trouble. The opposite should be true for the west: While the east deals with another blast of winter, the west coat will be warmer and no doubt happier than those of us with cold winds. If a trough moves through in the future that happens to run into all of these teleconnections, the CPC temperature outlook might seem a little strange. Warmer temperatures for a season experiencing another cold snap doesn’t make sense, suggesting things might warm up after the next bout of cold weather, or the winter might be backing off finally.

[swilburnwx]

Key West, FL & MJO

1/27/2018   7:00pm

While the rest of the country is preparing for another bout of cold weather, Key West is sitting in the 70s without much worry in the world. And good news, that doesn’t change much in the near future.

7 Day MOS for Key West, FL – 12z Jan 27

Average Total Cloud Cover – 00z Jan 29-00z Feb 2

On Sunday, Key West can expect to see some pretty overcast skies with temperatures sitting around the mid to upper 70s. Because the dewpoints are in the upper 60s, things will feel pretty muggy outside. Because of the high humidity, the clouds and some rain will stick around during and Tuesday. Once the cold front pushes through, the clouds take a break before partially returning at the end of the week when dewpoints reach back into the 60s.

500mb Height Anomalies – 00z Jan 29-18z Feb 1

Key West Sounding (Winds) – 14z Jan 28

This big story this week is the arrival of a small cold front passing through on Monday night. Once the front has passed, dry air and a ridge settle in over the US for a couple of days until another cold front arrives this weekend. In Key West, the biggest change will be how cloudy and windy it will be. According to MOS and the forecasted sounding for Sunday, winds will be blowing 20-25mph until Monday morning, when things slow down to around 5-10mph. Like I mentioned before, overcast skies will dominate Sunday and Monday. Tuesday, the clouds begin to clear up and Wednesday will be sunny and clear.

Total Precipitable Water and Winds – 18z Jan 27-03z Jan 30 

GFS 6-hour Precip Rate – 00z Jan 29-00z Jan 31

Throughout tomorrow and Monday, Key West can expect to see some showers due to a southerly flow of air and moisture. With incoming moisture and high dewpoints, it won’t be hard for showers to pop up all over Florida. It seems like this precipitation event is also a result of the approaching cold front, at least for the majority of Florida. Key West is much farther south than other areas, so the showers there are most likely due to the incoming moisture, and maybe a little bit of instability caused by the cold front. Luckily, this front is not terribly strong, so Key West can expect to see maybe 1” of rainfall over the two days.  In the above gif for precipitable water, the location of the front on Monday is very clear. Although we are not dealing with a polar-vortex of a cold front, dry air will still make its way into the southern US, and even Key West. Dewpoints on Tuesday and Wednesday drop into the 50s, making things feel much less humid and leading to clear skies on Wednesday. Temperatures will drop into the 60s, which is a little cooler than this weekend, but not too cold.

GFS Key West Sounding – 18z January 29

GFS Key West Sounding – 18z January 31

Here is a better look at the effects of that cold front. Even though it is not super strong, it is still enough to add a large pocket of dry air aloft, preventing clouds and bringing cooler, less humid conditions. The first sounding is for 18z Jan 29, right before the front moves through. The temperature and the temperature profiles are right next to each other (another indication of showers). The second sounding is from 18z Jan 31 – two days later. The temperature at the surface is cooler and the dewpoints aloft are much colder.

200hPa Potential Velocity Anomalies – 26 January 2018

On a larger scale, the MJO is slowly making its way around the globe. Even though this map of 200hPa potential velocity anomalies does not show the MJO itself, we can estimate its location using the negative and positive anomalies. Right now, the active, rising branch of the MJO is located over the Maritime Continent and is causing a lot of enhanced convection. For Key West and the rest of the US, the effects of the MJO should not be as obvious and severe as they are show here, (since we are much farther north than the ITCZ, which is a little farther south during our winter), but we could very well see some similar effects.

RMM Plots – 27 January 2018

RMM Plots – 22 January 2018

In the long term, the MJO seems like it will play a larger and larger role in US weather. On Jan 22, the RMM1 & RMM2 MJO plots forecasted the MJO to be active, but not too abnormal. Now, compare that with the RMM1 & RMM2 plots from Jan 27. Within the last two days, the MJO activity spiked and is now forecasted to travel around the globe without holding much back. Typically, when the MJO reaches phases 7, 8, and 1, US weather sees a direct impact from the convective branch sitting over the continent. When the convective branch is moving over the US, there is much more rising motion, leading to more clouds and potentially more precipitation in some areas. Much less solar radiation can make it to the surface, so temperatures tend to be a bit cooler as the MJO makes its way over the US. Now, the RMM plots only have the MJO placed over the Western Pacific at the beginning of February, so it will be interesting to see how the weather is impacted. If it stays this active when it makes it to us, we could see some interesting patterns happening with the winter weather.

[swilburnwx]

Roswell, NM Forecast

1/20/2018   9:30pm

Ah, Roswell – the alien hangout in the Land of Enchantment. Things seem to have been pretty mundane in Roswell the past couple of days (no new UFO reports), but things could get interesting for the beginning of the next week.

Bufkit Atmospheric Profile and Winds – 17z Jan 21

500mb Temps, Winds, and Heights – 00z Jan 21-06z Jan 22

One of the main stories with Roswell for this Sunday is the windy weather. The NWS in Albuquerque has placed Roswell and other cities under a high wind watch. Roswell can expect to see sustained winds 30-40mph, with gusts of wind even stronger, for the majority of Sunday. High winds mixed with incredibly low moisture means there could be some dust and sand blowing around, on top of the heightened danger of fires. The strong winds are a side effect of a strong, upper level shortwave trough that is making its way through New Mexico during Sunday.

SPC Fire Weather Day 2 (Jan 21) Outlook

Because the air is so dry with no relief in sight, and because the winds are abnormally strong with the passing of the front, the SPC has placed Roswell and other location in the southwest under an elevated fire threat. Should a fire break out, the winds will help the fire spread rapidly and the lack of atmospheric moisture will allow the fire to burn anything and everything it touches. It is important to remember fire safety rules for the next couple of days to eliminate the chances of a fire outbreak.

Bufkit Temperature and Relative Humidity

Precipitable Water and 500mb Winds – 06z Jan 21-00z Jan 24

As I have already mentioned, New Mexico is DRY. Nevermind that it is in the desert southwest, but there is no significant inflow of moisture coming from any location around Roswell. According to the NWS and forecast soundings, relative humidity values are extremely low – with a max value of 15% humidity. These conditions seem like they will last well into the end of the week, so it is important to practice fire safety. Because it is so dry, there is no chance of precipitation, and little to no chance of cloud cover. The lack of clouds means the sun will have no issue warming Roswell during the day, but the temperatures will plummet into the 20s during nighttime hours.

2m Air Temperature – 12z Jan 23-00z Jan 26 

Speaking of temperatures, they should be pretty stable for the next week. Since it will remain dry, the lack of clouds will allow the sun to warm Roswell during the day, but the temperatures will back into the 30s during nighttime hours. Highs during the day will reach the upper 40s to lower 50s. At the beginning of the week, the small cold front will cause nighttime lows to reach the lower 30s and upper 20s, but come Tuesday and Wednesday, nighttime lows should remain in the 30s.

500mb Height Anomalies – 03z Jan 22-06z Jan 25

In terms of atmospheric events for the next week, it should remain pretty quiet. Once the low moves out of New Mexico, a ridge sets up right over the south-central US, resulting in sunny skies and those stable temperatures I mentioned before. Towards the end of the week, another trough will set up off the west coast and will make its way back into New Mexico. Right now, the low does not look like it will be ask strong as the one passing on Sunday, and might even be immediately followed by another ridge.

[swilburnwx]

Raleigh, NC Forecast (Make-up Blog)

1/21/2018   7:00pm

Things have warmed up in Raleigh since the last cold front came through! Fortunately, those highs in the 60s should last for a couple more days before another cold front and kicks the moisture and warm air out of North Carolina.

Bufkit Sounding – 10z Jan. 21

Water Vapor Imagery – 2240z Jan. 20–0040z Jan. 21

Starting off for Sunday morning, the forecasted GFS sounding shows early morning fog forming in the area. This extra moisture is thanks to a low pressure system in the deep southeast slowly bringing warmer air into Raleigh. Because it has been so cold recently, the warmer air moving over a somewhat cool surface will result in fog for most of the morning, burning off completely by 4pm. Mostly cloudly skies will dominate for the rest of the evening. Monday morning, the same scenario will cause more fog in the morning, and scattered clouds for the rest of the day.

500mb Heights and Winds – 06z Jan. 22–18z Jan. 23

In the evening, the clouds begin to thicken due to an approaching shortwave trough moving through the United States. Behind this trough is another bout of drier air and rain that will hit Raleigh Monday night into early Tuesday morning. This trough is not a strong one, and will not bring a drastic change in temperatures, but a lot of the moisture will be pushed out by the dry air from the north.

GFS Total Precip Accumulation – 12z Jan. 23

Now, I talk about this moisture from the south making its way into North Carolina. While there is some moisture, the satellite imagery above shows that there is only a small amount of water vapor being brought to Raleigh. Because there is not a significantly strong inflow of moist, southern air, Raleigh is only looking at a total accumulation of 0.15″ of rain up to 1am on Tuesday morning. Throughout Tuesday, a chance of rain still exists, but only in the morning. By the evening, skies should be clear of clouds.

Bufkit Temperature and Relative Humidity – 18z Jan 20-00z Jan 23

The wonderful thing about rain and clouds with a weak cold front is that the temperature stays relatively stable. Once the fog burns off Monday morning, sunshine will raise temperatures to a high around 53˚F. More clouds will form in the afternoon, insulating some of that warm air into the evening, the moisture and leftover heat prevent the temperature from wavering too much. Monday night’s low will only be one to two degrees cooler than the high of the day. Because the clouds stick around into Tuesday morning, the temperature does not cool off. Come the afternoon, Raleigh can expect to see a high around 60˚F. The bad thing about cold fronts is that they bring drier conditions. Even though Tuesday’s high will feel wonderful, there will be few to no clouds insulating the surface, so nighttime temperatures will return to the 30s.

For the rest of the week, Raleigh will see sunny skies and drier air. Because the cold front wasn’t strong, we can expect to see temperatures similar to this weekend. No clouds means the surface will heat up during the day, but will cool off significantly during the night.

[swilburnwx]

Hunstville, AL Weekend Forecast

November 17, 2017   7:45pm

It’s been pretty sunny and warm in the Southeast recently! However, the chilly, fall weather will return in the form of a strong cold front moving across the Eastern US this weekend. Huntsville, what does this mean for you?

250mb Wind Speeds – 06z Nov 18 -18z Nov 19

While some areas east of the Great Plains will see the effects of the cold front early Saturday, Huntsville will not get much interesting weather until later in the day. As a strong atmospheric trough pushes across the Southeast, Saturday evening and night will be when Huntsville begins to see chances for rain and possibly some storms. Following the trough is dry, cold air that will keep Huntsville pretty chilly throughout the rest of the weekend and into nest week.

2m Temperature and 10m winds – 00z Nov 19-06z Nov 20

Thankfully, this cold front will cause temperatures to return to the fall-like weather we missed this past week. In the loop above, as soon as the front passes, temperatures drop into the mid 40s. The temperature keeps cooling as the night goes on, and the high on Sunday will only reach the mid 40s. Sunday night is when the heaters will become a life-saver, as the nighttime low will dip into the lower 30s.

Mean Sea Level Pressure & 3hr Precipitation – 15z Nov 18-09z Nov 19

One of the main stories with the cold front is that it will bring not only cooler temperatures, but a good amount of rain and a potential for some thunderstorms. As the front approaches Huntsville, there is a chance of rain as early as a little after noon. However, according to the GFS loop of 3hr precipitation above, the greatest chance of rain comes later that night. Heavier rain and storms will enter Huntsville in the late evening and will last for a few hours before the dry air behind the front arrives.

NAM Bufkit Winds – 18z Nov 18

NAM Bufkit Winds – 01z Nov 19

One of the main hazards that arrives with this cold front is the wind. During the late morning and afternoon, Huntsville will experience winds anywhere from 20-25mph. However, as the cold front gets closer and the pressure and temperature gradients increase, winds will speed up to 35-40mph. This does not include the potential for gusts associated with storms or the cold front, so late Saturday afternoon and evening will be definitely be windy.

NAM Bufkit Sounding – 19z Nov 18

Something interesting regarding a forecasted sounding for Saturday afternoon is the appearance of a capping inversion. In the lower levels, the air column is saturated, and rain will start to fall in Huntsville, but there is a pocket of dry air around ~850mb. The temperature of the parcel rises as the dewpoint lowers, causing a “cap” that will prevent deep convection from occurring. So according to this sounding, it is possible that Huntsville will see a couple storms, but mostly rain.

GFS 850mb Cyclonic Vorticity – 06z Nov 18-12z Nov 19

Despite the cap shown in the forecasted sounding for the majority of Saturday, the GFS shows a large amount of cyclonic vorticity ahead of the cold front. From the sounding, there is also a strong amount of wind shear due to the difference in wind speeds, and some directional shear in the lower levels. Because of the vorticity and hints of wind shear, it is possible that Huntsville could see some strong storms, maybe even some severe storms, on Saturday night.

[swilburnwx]

Savannah, GA Forecast

November 8, 2017  1:30pm

2m Temperature Anomalies – 00z Nov 9 - 00z Nov 11

Even though this cold front is not the end-all-be-all of cold fronts, it is still bringing significantly cooler temperatures throughout the rest of the week. In the above loop from Wednesday night to Friday night, temperatures drop to anomalously low values. The temperatures are only supposed to reach about 3.5˚F below normal, but along with a drop in dewpoint, the temperature will be very pleasant and less humid than the beginning of the week.

24-hour Precipitation Accumulation – 12z Nov 9 - 12z Nov 10

As the cold front moves through on Thursday, Savannah can expect to see about half of inch of rain throughout the day. The rain will start late Wednesday night, early Thursday morning and will last all day and into Thursday night. There might be some leftover, local showers throughout Savannah, but for the most part Friday morning will be overcast, but make way to sunnier skies later on.

Savannah, GA NAM Bufkit Soundings – 15z November 10

On Thursday, the cold front arrives in Savannah and brings temperatures down with it. Since the majority of rain is supposed to happen tomorrow, the sun won’t be able to heat the surface during the day and the cool, moist air will keep the temperatures in the mid-50s into Friday morning. Dewpoints also drop into the mid-50s, but it will not feel any less humid outside since it will be raining pretty much all day.

CIMMS Visible Satellite Imagery – Until 1615z Nov 8

From the VIS imagery above, it is evident that this front is very slow-moving and is taking its time to reach the East Coast. Ahead of the front, there is a large swath of clouds and rain from the less dense, moist air rising in response to the cool, dry air behind the front. Because this front is moving so slowly, it will likely be rainy and dreary all day and all night.

Savannah, GA NAM Bufkit Sounding – 16z November 10

Friday morning, we might see a few clouds because of the nighttime low reaching near the dewpoint, but we can see that large pocket of drier air aloft. Thanks to the weak but effective front, the upper atmosphere is much drier and the surface is cooler. Because the air is so much drier, there will not be much convection occurring during the day on Friday. There might be some clouds left behind in some areas as the cold front completely makes its way out of Savannah, but the sun will be able to heat the surface and get temperatures up to 63˚F.

[swilburnwx]

Nashville Weekend Forecast

November 3, 2017

Happy Friday, Nashville! This morning started with a few showers and thunderstorms, but let’s take a look at the upcoming weekend.

Water Vapor Satellite Imagery – until 1445z Nov 3

WPC Short Term Forecast – 18z Nov 3

By now, the storms around Nashville should be on their way out of the city. These storms are a result of a weak cold front moving across the US, bringing more of a potential for severe weather instead of cooler temperatures. In the WV imagery, we see that the front is not too visible in the upper levels of the atmosphere, and we cannot see a sudden pocket of dry air behind the storms. So even though a cold front is moving through, skies will not be immediately sunny and clear once the storms move away.

NAM Bufkit Relative Humidity and Temperature – 00z Nov 3

For the remainder of the day, we can expect overcast skies to stick around Nashville into the evening. According to the NAM model, the high for Friday will be around 74˚F in the late afternoon with clouds staying thick throughout the evening. Friday night the low won’t get below 64˚F thanks to the constant cloud cover insulating the surface, and because this front is so weak. There could be some showers overnight due to the humidity staying relatively high throughout the night.

700mb Vertical Velocity – 18z Nov 4

500mb Vorticity – 18z Nov 4

The NAM is showing a hint of positive vertical velocity near Nashville on Saturday, suggesting there could be some rising motion and cloud formation that day. However, the NAM is also showing negative vorticity advection and weak temperature advection, meaning more of a sinking air scenario. Because the air should be sinking due to negative vorticity advection and the lack of warm air coming into the area, any clouds that are left in the morning should make way to partly cloudy skies by the end of the day.

NAM Bufkit Relative Humidity – 00z Nov 3

Cloud Cover – 03z Nov 5 - 06z Nov 6

On Sunday, the sun finally makes a full appearance. According to both the NAM and the GFS, Sunday morning might be mostly cloudy, but by the afternoon, the clouds break up and the sun can shine. The rest of the day should remain pretty clear, until another atmospheric system moves through in the beginning of the week.

NAM Bufkit Temperature – 00z Nov 3

The temperature this weekend is interesting – it seems like a complete reversal of the recent cold front that made nighttime lows drop into the 30s. On Saturday, the clouds will allow the high to reach 75˚F before creeping down to 65˚F at night. Sunday, once the front moves out of Nashville and sunny skies return, temperatures are expected to reach around 80˚F in the afternoon.

[swilburnwx]

Caribbean Outlook

October 26, 2017 2:00pm

We have had quite the lull in tropical activity in the Atlantic basin recently. However, according to a recent discussion regarding the global tropical hazards, there is a chance that things could start back up in the next week.

5-day MJO Forecast – RMM Diagram

According to the most recent RMM diagram, the MJO is in phase 7 and is making its way towards the Western Hemisphere. The MJO is not as strong as it was last week when it was helping Typhoon Lan intensify in the Western Pacific, but it is still well above neutral. If the MJO is strong enough, it could potentially help any disturbances in the Caribbean to organize and/or intensify. Looking ahead, the MJO is, in fact, predicted to weaken as it continues its trek around the world.

200hPa Velocity Potential Anomalies – October 24

Velocity potential anomalies tend to match up with the location and strength of the active branch of the MJO. Looking at the map from October 24, the strongest anomalies are still over the Pacific, but as the active phase makes its way east, the Caribbean, and even the Atlantic, is already starting to experience conditions favorable for enhanced convection. Increased surface convergence due to westerly winds interacting with the Trade Winds is leading to more rising motion of tropical moisture, creating areas of cooler cloud tops in the Caribbean.

Atlantic Outlook – 8pm October 25

Right now, there is only one area in the Atlantic that the NHC is watching: Invest 93L. This invest only has a 40% chance of becoming a tropical cyclone in the next 5 days, but will it become anything?

Weekly Average SSTs – October 15–October 21

Weekly Average SST Anomalies – October 15–October 21

SSTs are not as warm as they were a few weeks ago. In fact, La Nina-like conditions are starting to be seen off the western coast of South America. We may not officially be in a La Nina, but the sea surface temperatures are looking like we are going in that direction. In terms of the Caribbean, waters are still plenty warm, with some temperatures reaching 30˚C. 93L has a large amount of energy it can still use if it gets its act together within the next couple of days.

Total Precipitable Water – October 26

In terms of precipitable water and moisture, 93L is in a good spot – for now. The strong atmospheric trough that just moved across the US brought with it a cold front that is still extending to the tropics. Once that cold front moves through the Caribbean, the colder and drier air will negatively impact any convection occurring in 93L. Once that convection slows down, it will be hard to get any deep convection with the dry air that will remain behind the front. It seems very unlikely that 93L will be able to form into anything worthwhile.

Vertical Wind Shear – 03z October 26

Shear, at least around the invest area, is favorable. Everywhere else, there is very unfavorable shear all across the Atlantic and the Caribbean, which is probably why the invest area only has a 40% chance of actually forming in the next 5 days. Once this next trough moves through, I doubt the Caribbean will be able to take advantage of the MJO in terms of tropical development. I do not want to say that nothing will form in the future before hurricane seasons comes to a close, but in the short term, I think the Caribbean will stay quiet. But according to some models, 93L might actually be something to watch.

HWRF 93L MSLP & 10m Winds – 18z October 26 - 09z October 29

ECMWF 500mb Height Anomalies – 12z October 26 - 12z October 29

The HWRF, which is based on GFS data, shows 93L bouncing around the Caribbean for a couple of days before getting its act together and moving northeast towards Cuba and the southern tip of Florida. Meanwhile, the ECMWF model shows absolutely nothing coming from the Gulf of Mexico after the next cold front moves through. Something to note with the HWRF model is that it struggles with systems that are not very organized. Sure the model might be showing something forming, but given the lack of moisture, strong shear, and cold air on the way, it’s hard to tell what the model thinks will cause the storm to organize.

93L does not seem to pose much of a threat in neither the short-term or the long-term, but since at least one model is showing the system forming into something more, it is an area to watch in the next week.

[swilburnwx]

West Palm Beach, FL Forecast

October 19, 2017 5:00pm

Ah, the Sunshine State, known for its tropical climates and abundant thunderstorms. You would think that the state would see more sun than other states with its nickname, but it actually experiences more thunderstorms than any other US state. This week, West Palm Beach proves that this state is not always as sunny as it may seem.

2m Dewpoint – 18z October 22

Bufkit 12z NAM Temperature and Dewpoints – 12z October 19 – 00z October 23

In West Palm, the dewpoints have been anything but pleasant, and there is not much change throughout the weekend. Dewpoints in the lower 70s and temperatures in the upper 70s and lower 80s have been providing partly cloudy skies, some showers, and a lot of humidity. Unfortunately for those who live in West Palm, the weekend ahead does not look much different than today. Something interesting when looking at the moisture around West Palm Beach is how the satellite imagery does not show any moisture in Southern Florida. So why is it so humid?

CIMSS Water Vapor Imagery – Until 20:45z October 19

925mb Isotachs and Geopotential Heights – 12z October 19 – 21z October 23

Despite the seemingly arid atmosphere shown on the satellite imagery, multiple models forecast clouds and some chances of precipitation as we reach the beginning of next week. The reason why these two products don’t make sense is because water vapor imagery can only analyze the upper layers of the atmosphere. So, while the top of the atmosphere is dry, there is an almost constant surface flow from the Atlantic Ocean into Florida. 

These surface winds are responsible for bringing in moisture from the east and southeast into West Palm, keeping those dewpoints high and the air sticky from humidity. In the above loop, we get a glimpse at how the winds begin to change on Monday due to an approaching cold front. The winds shift from easterly to southerly, which means they will bring even more moisture into West Palm before the cold front arrives. Because Monday winds will advect tropical air into West Palm, we can expect to see mostly cloudy skies with the high humidity.

300mb Heights and Winds – 00z October 23 – 06z October 26

On Monday, the upper level winds and surface dewpoints do not alter much from the weekend. Sadly, Tuesday follow suit with high dewpoints and high humidity with temperatures in the low 80s. However, on Tuesday, things begin to change. A strong atmospheric trough will propagate across the United States early in the week and from Tuesday night through Wednesday, it reaches Florida. Now, the main benefit of this trough is that it will change the direction of the lower level winds that have been bringing moisture into the area. After the cold front, dewpoints will go from the 70s into the 50s, making the air feel much drier than the weekend.

Cloud Cover % – 00z October 25 – 00z October 21

Thankfully, the effects of this trough will last until the end of the week. Dry air behind the impinging cold front will keep the dewpoints low while the daytime temperatures have the ability to reach into the upper 70s. Because that air will be drier, less clouds will form and the sun can heat the surface. Since West Palm is still close to the tropics, some areas of convection cannot be ruled out when the sun heats the surface. A drier Florida does not equate to a dry Colorado, and there will still be moisture in the atmosphere that can lead to cloud formation.

Nighttime temperatures will also drop a little lower than they will be able to this weekend. Once this cold front passes, lower dewpoints and drier air at night make for partly cloudy skies and cooler nighttime lows. Towards the end of the week, it looks like temperatures and moisture return to their old ways with highs in the mid 80s and more humidity.

6-hour Accumulated QPF – 09z October 21 – 06z October28

The trough moving through Florida sounds great, but what does it mean for precipitation? Throughout the weekend, the main cause of rain looks to be pop up showers in areas with abundant moisture. As the trough arrives, the chance of rain and the QPF values do increase, but not enough to cause concern. The drier air moving into the area is denser than the moist air, so a chance of convection and showers is possible in multiple places, with 6-hour rainfall of close to half an inch. Once that dry air takes over in Florida, the chance of rain drops significantly.

In summary, West Palm Beach, FL is holding onto summer as long as it can. Thankfully, this trough should be enough to coax the first quasi-autumn conditions to arrive in the city. Hopefully the lower temperatures and dewpoints make another appearance in the future.

[swilburnwx]

Towson, Maryland Forecast

October 12, 2017 10:40pm

For those of us in the Southeast, the recent cold front has been the primary focus of our conversations. Temperatures finally dipped below the 80s and some people even broke out their sweaters in the morning. For the Northeast, they have already experience some of those glorious fall-like temperatures. Here in Mississippi, the fall temperatures aren’t sticking around for too long, but what about in Maryland?

925mb Heights and Winds – 18z Thurs - Sat 06z

2m Relative Humidity and Streamlines – 18z Thurs - 06z Sat

Right now, things in Maryland are pretty dreary. After a weak cold front moved across the Eastern US, a constant easterly flow began pulling moisture from the Atlantic into Maryland. This flow has kept bringing more moisture into Towson, causing the relative humidity to remain high throughout the state. Because of the amount of moisture in the atmosphere, overcast skies are preventing the sun from warming the surface, which is why the temperatures have remained in the 60s. We can expect these clouds to stick around until Saturday, when the ridge over the Northeast strengthens.

2m Air Temperature – 18z October 14

2m Dew Points – 18z October 14

As soon as the clouds move out of the area, the sun will be shining bright and temperatures will reach the upper 70s. Saturday and Sunday are looking to be the complete opposite of Friday – no showers, few clouds, and warm temperatures. Dewpoints will be in the upper 50s, meaning Towson should not feel to terribly humid in the afternoon, but the mornings might feel a little damp. The reason why temperatures suddenly spike into the upper 70s is due to the ridge to the north strengthening once again. While the ridge strengthens, more subsidence occurs and less clouds will form. Without clouds in the way, the sun will have no issue warming up the atmosphere quickly.

500mb Height Anomalies – 06z October 15

250mb Winds and Streamlines – 12z October 15 – 18z October 17

The recent cold front caused a reversal of what we have been seeing recently (warm temperatures with no end in sight), but unfortunately, the dreaded ridge strengthens again. Thankfully, fall temperatures will return late Sunday night into Monday morning. A strong trough will arrive in the Eastern US, finally pushing that strong ridge eastward. This strong cold front will bring in cooler air from Canada into Towson, causing a stark difference in temperatures. Temperatures will be in the upper 70s on Sunday, but will drop to highs in the 60s on Monday.

300K Wind, Pressure, and Moisture – 00z October 16

According to isentropic analysis, Towson does not have a large chance of seeing many showers. Once the front reaches Maryland, the amount of moisture diminishes, leaving only a trace of moisture associated with rising motion. Some areas could see some rain while the front passes on Sunday night, but there does not seem to be a threat of severe weather. Looking behind the front, we see a large area of very dry air. Cool temperatures and dry air do not bode well for convection, so expect to see sunny skies with mild temperatures on Monday.

Cloud Cover – 09z October 16 - 12z October 20

For the rest of the week, Towson can look forward to seeing sunny skies with very few clouds. The cold front will cool things off significantly, especially during the night. Because the air is so dry, less clouds will insulate the surface, and whatever warmth is gained from the sun during the day will have no trouble escaping into the atmosphere at night. Expect to see nighttime temperatures well below the daytime highs. Some areas could even see lows in the 40s, according to the most recent GFS run. Towards the end of the week, temperature warms and the pressure builds once again, though not as strong as this week.

Overall, Towson, get excited for fall! Ideally, the majority of us in the eastern US would have liked to see these kinds of conditions at the beginning of October, but beggars can’t be choosers. Enjoy your pumpkin spice lattes while the rest of us in the Deep South wait for fall to stay!