First Chance of Accumulating Snow: Early Thursday
Probability of Accumulating Snow: <10%
This winter season is not taking any time getting started! The Mid-Atlantic's first winter storm is on the horizon as it sits about 48 hours away. This will not be a snow maker many. However, this is the first shot at seeing some snowflakes and wintry precipitation for a large swath of the region.
Low pressure moving along the Appalachian Mountains is forecast fade and develop a new storm off the Coast. This new storm looks to move along and off the Eastern Seaboard on Thursday. As this coastal storm gets going, it is expected to throw precipitation into our area. Though the details are still murky, this is my current thinking:
Precipitation may start as a wintry mix overnight Wednesday into early Thursday morning. With the warm coming up from the south, many will turn over to rain quickly, especially coastal areas. This rain looks to persist through the afternoon. Precipitation stay wintry longer for the highest elevation NW of I-95 in Western MD, WV, Western VA, and Central PA. Any accumulation would most likely occur on grassy surfaces although if a period of moderate snow develops, especially before sunrise, some slick spots could develop on roadways NW of DC. This is expected to be an all rain event southeast of DC, as shown below.
Where wintry precipitation will hold on longer, the National Weather Service has gone ahead and issued the first Winter Storm WATCH of the season. It is in these higher elevation areas where snow/ice totals could be impactful.
How much precipitation are we talking? Not much. While this may be our first winter storm, we are not looking at a lot. Nevertheless, here is my first call on snow and ice totals for the region:
Yes, winter is getting off to an early start! This is the second earliest I have ever posted a winter weather forecast. As my winter outlook stated, our southern Jet Stream (storm track) will be very active this winter; like it was this summer and fall. Now that temps are lowering, this will lead to some of these being wintry. While the wintry side of this one will not be widespread, it is encouraging for snow lovers. These early season storms are very climatology driven. It will be the highest elevations, areas away from the coastline. It will be these areas that will be looking at roadway and school/business impacts on Thursday. I will update this forecast tomorrow, and that is when we can start talking school odds. In the meantime, keep it locked in with JB Weather. Southern Maryland's premier weather forecasting outlet!
-John A. Bordash
Living on the edge is never easy, and we still sit pretty close with regards to this major East Coast storm. However, it does appear that the storm is taking track closer to the coast, which spells good news for snow lovers. It does look increasingly likely the area will end up with some accumulations, which could end up on the moderate to significant side, especially for coastal areas. Snow starts around midnight tonight, and continues through morning. The heaviest should be right before sunrise. Snow tapers off by lunchtime.
For the coastal region, over 6" or so of snow is likely mainly tonight and tomorrow. The heavy snow there will be accompanied by Blizzard conditions (winds over 35mph for 3+ hours). More modest snow will be west of there, around the Bay. Places such as the Middle/Northern Delmarva, Southern MD and Tidewater are on tap for at least 4" of snow. Winter Storm Warnings are largely in place there (except for Southern MD). The lowest amounts will be along I-95, through DC, Baltimore, and Richmond. Those locations should see a general 1-3", and are under Winter Weather Advisories.
Increased snow totals also means the increased chance of school closings and delays. School districts in Southern MD are almost guaranteed a delay, with Calvert and St. Mary's having a good shot at their first snow day. For counties along and west of I-95, it will be a close call for delay. If the forecast verifies, I could definitely see delays as far west as Montgomery and Prince William Counties.
The coastal storm we've been watching the last few days is almost here. Poised to provide us with periods of light to moderate snow. Even though I'm forecasting moderate accumulations across the region, confidence with this storm is still low. A small wobble, either further westward or eastward, would have big implications. And as is the case in most storms, dry air across the region could also hinder snow totals. Locally higher totals could be possible for some, if all aligns right. Nevertheless, as things stand now, Southern MD is in for a decent snow event, with an all out blizzard on tap for coastal areas. Travel will be difficult tomorrow for many. Stay with JB Weather, on Facebook and Twitter, for the latest information.
-John A. Bordash
There is confidence that there will be some snow tomorrow, possibly moderate, and that conditions will generally deteriorate as you head northeast. A Winter Weather Advisory has now been issued for tonight through tomorrow, for Southern Maryland, the Mid-Shore on the Delmarva, and Central Virginia. Areas further to the south and east are under a Winter Storm Warning. The National Weather Service, in a rare move, has also gone ahead and issued a Blizzard Warning for the Virginia Beach/Norfolk/Hampton Roads/Chesapeake Area.
Confidence is lower than usual, but finally starting to increase if only a little. The storm is forecast to rapidly develop just as it is approaching the Mid-Atlantic coast. Slight deviations in the rate of development and the storm track will likely have large implications for how much snow falls in the region. Shown below are two outputs from models I look at when making my forecast. On one hand, the European is far less aggressive with potential totals. A general 1-2" in Southern Maryland, with 2-4" on the Shore. On the other hand, the NAM Model is very aggressive with totals. That model has over a foot of snow on the Shore, a general 4-8" across Southern Maryland, and 1-3" in the DC Metro. Currently, I do not buy what the NAM is putting out. I believe the final solution is somewhere in between these two outputs, but I am swaying closer to the Euro. What I do like about the NAM is that it shows the sharp cutoff in totals that will exist.
Snow likely starts to fall tonight around Midnight. Conditions will likely deteriorate to their worst tomorrow morning, before sunrise-- especially east, as the storm intensifies. During this time, moderate bands of snow may begin pivoting around the storm's center off the coast from east to west, blown around by gusty winds and with falling temperatures.
Roads will become slick when the snow is falling. The snow tonight shouldn't be particularly heavy, so crews should be able to keep up with the snow on major roads. Although iciness on the roads is often a bigger threat at night than during the day. Airports may experience a few delays, especially if the storm comes further west, providing more snow. Widespread closures aren't anticipated in the D.C. area, but are possible at airports up the Northeast Corridor, especially tomorrow afternoon into the night, which would probably have significant impacts on flights scheduled to depart or land at National, Dulles and BWI.
What about area schools? With the core of the snow in the intimidate region falling in Calvert and St. Mary's Counties, I would say those districts have the best shot a closing (and that chance is high). In the very least, I would expect delays there. Anne Arundel, Charles, King George, and Prince Georges Counties have a modest shot at a delay. However, with the heavier snows falling well southeast of there, I would be cautious in hoping for closing. It is too early to make any predictions about schools for Friday. Check back tomorrow for that forecast (if it is needed).
As you can see, there is both the significant possibility of lower and higher snowfall totals than forecast. That is why it has been difficult to make this forecast. If the storm develops more slowly and further to the east, we may get very little snow. If it develops rapidly and further west, we may get hammered with more than 6". Satellite and radar tonight will serve as useful tools in monitoring how the storm is evolving. Stay with JB Weather on Facebook and Twitter for the latest updates on how the storm is involving, and the calls that area schools are making.
-John A. Bordash
Next Chance of Accumulating Snow: Wednesday PM - Thursday
Probability of Accumulating Snow (1" or more): 60%
Most model guidance which has come in since last night continues to show a high likelihood of snow Wednesday night into Thursday. As I've been discussing for several days now, this forecast has been extremely difficult. Unfortunately, the normally added benefit of nearing closer to the onset of the storm isn't helping a lot.
Why is the forecast so uncertain? It's because the storm is basically forecast to develop explosively very close to us and any minor shift in the timing or placement of this development has major implications for the snowfall amounts. If the development occurs later and slightly further east, we could get very little. Or if it happens earlier and a hair further west, we see a more significant event. Further east northeast, from the Delmarva peninsula to Boston, the uncertainty is reduced because those locations are sure to be closer to the storm center which will have had more time to develop, especially as you head north.
As shown, the most significant impacts will be felt closer to the coast, and up in New England. If this storm were to track just a smudge more westward, more moderate impacts would shift into Southern Maryland. Snow likely starts to move into Southern MD after sunset around midnight, Wednesday night. As the storm starts to strengthen, snow will continue for areas east of I-95 throughout early to mid morning. Moderate to heavy snow falls on the Delmarva during this time. Winds will also be rather gusty right along the Atlantic shoreline. This gusty, onshore winds increase the risk for coastal flooding. The storm will begin to move away, and snow will shut off by lunchtime.
All-in-all, this does not appear to be a major snowstorm for Southern MD. However, a slight shift westward could spell a different story. Right now, prepare for light, accumulating snow to impact the area Thursday morning. Some travel and school delays are possible, but that will come into better focus tomorrow. Impacts look to be minimal, but whatever falls will stick thanks to our recent cold blast. This has been, and continues to be, a changing forecast. The minor details, surrounding the track of the storm, should come into better focus tomorrow.
Next accumulating snow chance: Wednesday Night
Probability of accumulating snow (1" or more): 50%
Model guidance this afternoon has shifted the track of the developing storm on Wednesday westward and closer to the coast. As a result, it looks like there is a better chance the region sees accumulating snow. This remains a very delicate situation where very modest shifts in the storm track could make the difference between no snow and a classic January snowstorm.
An area of low pressure is forecast to develop near the Florida coast, and should track northward. As it does so, this system will get very strong. It is very rare to get storms in January as strong as this is forecasted to be. That is the part of the forecast that is pretty much nailed down. The questions currently surround the track of the system. Show below are our two possible scenarios.
Scenario One would lead to a moderate snowstorm for many south and east of I-95. On the other hand, Scenario Two would be just light, glancing blow that doesn't amount to much. Right now, both of these possibilities have a 50% chance of occurring. However, it is important to note-- more of our weather guidance has been shifting towards a Scenario One solution. It is safe to say that the probabilities for Scenario have gone up. Still a tad too early to say which track will happen, but we should know more after tonight's data comes in. With the way things stand now though, I'm starting to believe that a coastal track may be a more likely solution.
It is too early to say, with confidence, how much snow would fall, what area schools would do, or how travel would be impacted. After reviewing tonight's data, and looking at our atmospheric set up tomorrow morning, I will release a first call on this event. Stay tuned, especially if you're south and east of I95. The threat of accumulating snow late week, is real.