Not much change from the last map… mostly some expansion of the 4-8″ contour over the mountains and cutting back totals a little bit on the parts of the fringes. I don’t trust how bullish the models are on the snow maps because it looks like temperatures may end up a bit warmer than the raw 2mt in the evening, taking the snow longer to start accumulating. Maybe the front-end stuff will be heavy enough to stick earlier, but I have my doubts.
Still some wiggle room with this, but models are coming to a nice consensus regarding the track, which is pretty much where my snow map is now and was yesterday. There appears to be more upside potential than downside with this event in the 1-4″ areas and up in the mountains, especially if you trust the higher QPF model solutions.
With what is hopefully our last snow threat for the season in the greater D.C. area, there is still a fair amount of uncertainty with the ultimate track of the system in addition to how wet it is. Lower than normal confidence with this forecast, which favors the Euro more than the GFS.
My forecast seems somewhat conservative compared to what some of the models are showing, so I imagine there is probably more upside potential than downside with this disturbance. This thing could still shift some 30-50 miles north or south, so don’t get too hung up with exactly where all the contour edges are at this point.
UPDATE March 2nd, 2pm EST: After seeing the latest model forecasts and trends, I would probably shift the 4-8″ and 8-12″+ contours south by about 15-20 miles.
Shifting everything a bit south from the initial forecast and added locally 12″+ wording for the mountains. Accumulations are for snow and sleet, though it will be a mostly snow event in the higher total areas.
If the sleet holds out for longer in the morning then totals may be cut down, but on the flip side once the cold air does arrive, we could start to see some higher ratio snowfall.
Models may continue to drift south, but I don’t think it will go much further south if they do. For the DC area, expect some rain to start tomorrow afternoon, which may briefly change over to freezing rain before the sleet moves in. After some sleet, over to all snow probably a little before morning rush hour… then snow through the afternoon hours.
And then we get hit by frigid air. Joy.
Meteorological spring is here, but winter isn’t done with us yet. Most of the region will actually start off as rain, but a very strong cold air mass will push southward, bringing the low-level air below freezing and changing areas over to freezing rain and sleet before finally transitioning to snow. The models are handling the speed of this cold air push differently, so there is still a fair amount of wiggle room with the snow totals.
There is still room for this to move north or south by a decent margin. I’ll have a final update after the 18z models come in.
A trough will traverse the Ohio Valley today and will start to take on a negative tilt as it reaches the East Coast, with a nice vort max developing over the Carolinas that will allow for a rapid strengthening of the surface low once it moves off the coast. Cold air aloft and the upper-level dynamics will be fairly supportive of snow, but somewhat-limited moisture and a warm boundary layer (despite the snowpack) will prevent a bigger snowfall within the forecast region.
Risks are more towards the lower side across the region with this system, though there is some upside potential near the coast if the low can strengthen faster. A little event to top off this snowy period before temperatures jump well above normal next week.
Only real notable adjustment for the final map was the expansion of the 12-18 contour and addition of locally 12+ over northern Maryland and into Pennsylvania. Expanded the 8-12 contour eastward slightly near I-95 and bumped the higher totals in North Carolina eastward a bit. Small changes to the western cut-off of the system as well.
There is more risk to the higher side west of I-95 and equal risks along and east of I-95. I will be in D.C. tonight into tomorrow to cover the storm!
Not incredibly different from my initial forecast… still uncertainty with the low track, which could cause more/less sleet and rain along the coast and could move the western edge of accumulation west/east. Also have to watch that band on the west side of the storm for possible higher totals. Hard to tell if I should lean more GFS, Euro or just split the solutions.
Notable differences are 1) eastward shift of the 4-8 and 8-12 contours from central Maryland through northern North Carolina, 2) eastward shift of the western cut-off, and 3) addition of 12-18 contour in Virginia and extreme northern North Carolina. I think there is still more upward potential than downward west of I-95, but I am unsure of which way to lean along and east of I-95, where mixing could cut down totals but banding on the back side of the storm could boost totals.
Significant icing (0.25″+) is also possible in the Carolinas with this event, which could cut down on snow totals around Raleigh and Charlotte.
Even though the event will be underway in southern North Carolina tomorrow morning, I plan on issuing a quick update in the early afternoon tomorrow because Virginia northward could still see some decent shifts and I want to leave room to adjust if needed.