A classic Southern storm will move up the coast today, wrapping in moisture and cold air, and producing a wintry mess of precipitation. Rain or a rain/snow mix this evening is likely to gradually transition to wet snow overnight and into tomorrow-- that could be moderate to heavy at times. Several inches are possible for areas east of I-95, with most accumulation on grassy areas. However, as snowfall rates pick up and darkness settles, slick roads will become a possibility. The snow ends before midnight. Sunshine returns Sunday, but it will be on the brisk side.
I am confident that we'll have a sloppy mix of precipitation and that it will change to snow. The big questions are will it snow hard enough and will temperatures fall quickly for snow to accumulate, as I detailed this morning.
The National Weather has hoisted Winter Weather Advisories for all the locations in purple. Generally, I'm expecting 2-5" east of DC, in the advised area, and 1-3 west of DC. A Winter Storm Warning, shown in pink, has also been issued as a heavier band may try to bring 5"+ of snow to Southern MD, and potentially to Delmarva as well.
A significant obstacle for snow accumulation is the relatively "warm air" that will be in place when the precipitation first arrives (in the upper 30s to 40s in some spots). It will take some time for the precipitation to cool the air and for precipitation to change from a rain (or a rain/snow mix) to snow. In the past, some of our biggest underperforming snow events have occurred when the changeover to snow took longer than expected. And, the warm ground could limit accumulations.
Precipitation has already started to move into the area. Early rain starting to mix with some snow and sleet already, which does bear good for snow lovers. Right now, all the precip is light, but it will pick up in intensity tomorrow. When will the heaviest snow fall? Most likely from sunrise to late morning.
We have talked about this storm potentially not bringing as much snow as the forecast called for. The next question is, could the storm bring more snow than expected? Yes. In order for this happen, we will need heavy precipitation to develop. That will serve to cool the air and high snowfall rates might overcome the effect of the warm ground. There's a 1 in 4 chance of 6-8" in a few spots. For that to happen, temperatures will need to be lower than forecasted, and as mentioned, heavy bands do need to set up.
Overall, as a snow lover, I'm liking what I see for this storm. All the ingredients are coming together for a decent December snowstorm, especially for Southern MD and Delmarva. A lot things are at play here, and there are a lot of variables. Stick with JB Weather for the latest updates and continued coverage!
Next Chance of Accumulating Snow: Friday - Saturday
Probability of Accumulating Snow (1" or more): 60%
Our first snow event of the season is on track to arrive tonight. The big question is how much snow and how big of an impact. Highs today will reach into the 40s, and ground temperatures are relatively warm, but temperatures are on their way down with chances of some accumulating snow tomorrow on the rise
Light precipitation should begin during the evening. It should be in the form of rain in many spots, though a rain/snow mix is not out of the question. Temperatures will be in the mid-to-upper 30s and falling.
Precipitation will spread over the area during the morning on Saturday and should stay mainly snow for areas west of the Bay, as temperatures fall to near freezing. Some accumulation is likely, especially during the morning on Saturday. Snow will mainly stick to just grassy, and untreated, areas. Snow should begin winding down around 5-8 p.m.
Another question/concern that I have are the temperatures. Throughout the majority of this event, temperatures will be in the middle 30s. That means that snow will have a hard time sticking initially. However, if the snow can fall fast enough, in heavier bands, the snow would be able to accumulate (which is what looks like will happen). Dry slots are also a concern with this storm, and where they would set up. Snow may mix with sleet and rain at times, especially along coastal areas, cutting down totals. With all this all in mind, I have to say-- this is a low confidence forecast. It's not often I say this, but, it's not a guarntee that my forecast will verify for everyone. The small micro-climates and variable conditions make this a difficult forecast. It is very possible that some see more than forecasted, and equally as possible that some see less than forecasted. Nevertheless, I think this forecast is good general baseline.
We are now within 12 hours of this time period of wintry weather starting, and we have a much better idea of what will happen than we did yesterday. However, there are a few things we do not know, and that we probably won't know until the event starts. Nevertheless, I think after this storm, we will be done with winter.
What we do know is that a weak area of low pressure, referred to as a clipper, is currently moving out of the Midwest and into the lower Ohio River Valley and Mid-Atlantic. As it moves closer towards the Mid-Atlantic, and surge of moisture will overspread the area around 5pm (give or take a hour or two). This initial surge of moisture should be all rain. If temps can drop quick enough, that surge of moisture may be able to end as some snowflakes around 10pm or so, but don't bet on it. It's during this time that areas north and west of DC should see most, if not all, of their accumulations. There will then likely be a little bit of a lull once that round of precip ends around midnight.
As that weak area of low pressure, moving out of the Midwest, dies off, a coastal storm (which is already developing), will take over. That coastal storm will move northward throughout the night, and bring in our next surge of precip into the area, which should be mostly snow.
What we don't know mainly concerns the coastal system. The biggest question is, "How far north and west does it track?" The further northwest it is, the more snow we could see. Right now, it appears that the coastal storm should stay far enough to our southeast to spare us of a significant snowfall, but it should come close enough to give us some snow.
Another worry I have concerns the temperatures during this event. Temps will only be marginally cold enough for snow (31-34). However, if the storm can come far enough northwest, we will see heavier precip, which would overcome the temps and cool our atmosphere. Temperatures will also determine what sticks. We'll need temps to be closer to 32, or below, to really pile anything up. Roads should be fine. Our snow totals will be dependent on how low the temps get and how heavy the precip is (which is dictated by how far NW the coastal storm can come).
Currently, we have a Winter Weather ADVISORY up for a large chunk of the Mid-Atlantic for the possibility of at least 2" of snow. Again, the totals NW of DC are dependent on the first round of moisture, and I'm not sure that will have enough of a punch with that to bring more than an inch or maybe two to most locations. I think that most areas southeast of DC should be able to meet the advisory criteria of 2" with the coastal storm.
Impacts across Southern Maryland should be minimal to moderate. Right now, I do expect delays and a few closings for area school districts (refer to the School Odds below). Expect a few slick spots on the way to work tomorrow morning as well. For federal and military employees, I don't think you will get a delay (I'd place it a 30% chance), but I could see Liberal Leave/Telework being an option that is offered.
If this coastal storm tracks further south and east, and we don't see the snows we're expecting, everyone should go to school on time, and there would be no issues with the AM commute. If the storm comes a little further north and west than expected, then the chances of closings and delays goes up along with impacts in the morning. Remember, this time of year, it is hard to accumulate snow on the roads. With this storm, it's more so the timing, than the amount.
The Bottom Line is that snow looks likely tomorrow morning. An initial area of precip will move through tonight giving the NW DC suburbs their snow, while we should get rain. A coastal storm will then head northward, before going out to sea, which should give us our accumulating snow in the morning. Remember, this time of year, it is hard to accumulate snow during the daylight hours. We could see more snow if this coastal storm moves further NW than thought (25% chance) and we could see less if it stays further to our SE (20% chance). If my forecast verifies, as I think it will, there will be a few issues tomorrow morning with some slicks spots. However, because of the timing we could see area schools opt to delay or cancel classes. Temps warm to near 40 in the afternoon, so any snow should be gone by then! Stay with JB Weather for continuing coverage.
February will definitely live up to to it's reputation as a winter month over the coming days. Not only am I tracking bitter cold on tap for late this week and weekend, but I'm also watching a storm chance for early next week.
Cold air moves in tonight on the coattails of some breezy northwest winds. For next 4-5 days, I don't think we see a high on the better side of freezing, and if we do get above freezing, it'll be for an hour or two. It looks like we max out between 30-32 Thursday and Friday. Temperatures on Friday will actually drop throughout the day as a cold front moves through that will usher in even colder air! We stay in the 20s this weekend with Saturday night offering some record cold. Lows in the single digits will challenge many records and the gusty winds will make it feel like we're well below zero. It looks like we do eventually warm up next week, which should be welcomed by many.
In my forecasting expiernce, I have learned that when you're dealing with arctic air, there is almost always a snow chance when the cold air moves in and/or when the cold air leaves. We could have some flurries Friday night when the coldest air moves in with the cold front. However, I'm more interested with the potential early next week, when the cold air leaves.
It looks like we'll have a storm heading northeastward somewhere along the east coast between Monday and Wednesday next week. Now I'm still uncertain about the storm track. A track to our northwest, across West Virginia, would be a warmer solution and would favor a mainly rain solution w/ a few snowflakes at the onset. If the storm takes more of a track like the second one, along the coastline, we would be colder and would favor a more wintry solution. I think we'll see a mixture of the two tracks. An initial low pressure system would try to take track 1 but then is forced to form a new low pressure area that follows track 2. Those types of set ups tend to favor at least some type of a wintry solution. It's also really hard to just have entrenched cold air move out of our region, so temps may very well stay in the low 30s Monday and maybe hitting 40 on Tuesday. It's all just speculation at this point, and we won't know details until we get closer to the weekend.
The Bottom Line is that the next few days are going to be extremely cold and as our cold air tries to moves out, we could have a storm to deal with. There are a few unknowns this far out, especially with our storm threat. Don't make any changes to your schedules for early next week yet, but know that there is threat for something early next week. We'll have more details in the coming days. We first need to focus on the bitter cold for late this week and weekend. Stay with JB Weather for the latest Southern Maryland weather forecasts.
It seems like winter has really gotten its act together over the last 2 weeks as most now sit with above average snow and near normal January temps. I am now tracking a storm that threatens to bring parts of the Mid-Atlantic a decent snow. However, we're not included in those getting a decent snow, but the timing of when we get our snow could be worrisome.
Over the past few days our models have really come into agreement, for the most part, on how the storm will evolve. It currently appears that we'll have an area of low pressure move out of the Ohio Valley and right through the Mid-Atlantic overnight into tomorrow morning. As that happens, we should see mainly rain showers with a few areas northwest of DC having their rain showers mixing with some snowflakes that could accumulate. Our rain would have the best chance to mix in and/or switch over snow for a brief time tomorrow morning before switching back over to rain
Tomorrow, our low pressure redevelops as a coastal low, that will track up the coast. As this happens, we switch back to rain after any snow in the morning and we will stay that way throughout the day Tuesday. As cold air comes in, we may switch back to snow overnight Tuesday into early Wednesday morning before any precip ends. Basically, we have to chances of snow in this storm: tonight and tomorrow night.
This set up where we are dealing with two lows is referred to as a "Miller B" set up. A Miller B setup is never friendly to Southern Maryland snow lovers.
Temperatures, as is normally the case, are concerning to me as a snow lover. I don't think we fall below freezing until Tuesday night. Temperatures will only be marginally okay for snow tonight. The further north you are, better the chance of seeing snow, further south the opposite is true.
The National Weather Service has posted Winter Storm Warnings for the counties where the highest snowfall accumulations are likely to be. In Southern MD, Anne Arundel is included, but if you're south of Route 50, don't expect to see too much, that warning is more so for the northern end. Winter Weather Advisories are posted in locations where at least 2" of snow is possible, and PG County is included. No "core SoMD counties" are included because we likely won't meet that 2" requirement.
While we won't see a lot of snow, generally under an inch, and any snow that falls would do snow right before the Tuesday AM Rush (may linger into the Rush) and again before the Wednesday AM Rush. Because of that, school systems, especially northern ones, may want to delay to allow for any slush of icy spots to clear. If the snow falls longer and can accumulate more, the snow may last long enough in the morning to make any travel before 10am unsafe, which could lead to a close. This is true for not only Tuesday morning, but Wednesday morning as well.
The Bottom Line is that this will not be a big snow event. Most of Southern MD will see snow totals under an inch as most of this event is rain. Any snow that falls would do so before the Tuesday AM Rush and the Wednesday AM Rush. It is because of that timing that schools may need to delay or close. It's not amounts, it's timing. I'm more confident in this forecast than I was for Friday's snow event, but a few things could still change. Stay with JB Weather for the latest information.