Snow possible Sunday night, but underwhelming accumulation odds

National Weather Service snowfall forecast through 6 a.m. Monday.  Note: Some additional snow may fall beyond that time.  We agree with this map, though be aware it illustrates a more conservative snowfall scenario.  It is not out of the question, a slightly snowier scenario could materialize.

National Weather Service snowfall forecast through 6 a.m. Monday. Note: Some additional snow may fall beyond that time. We agree with this map, though be aware it illustrates a more conservative snowfall scenario. It is not out of the question a slightly snowier scenario could materialize.

We continue to track an opportunity for some late season snow Sunday night into Monday morning.  But the critical ingredients for disruptive accumulations – heavy precipitation and cold air – seem to be just a hair lacking.

Here are the latest thoughts from Wes Junker, our winter weather expert:

Ugh! The forecast remains a tricky one as the models continue to forecast that a low will track to the Ohio Valley and then a new low will reform along the East Coast.  The models, however, diverge on whether we get dry slotted or whether a period of heavier precipitation develops over our area in response to the new low.  They also differ on the timing of the bulk of the precipitation. Some models delay the heaviest precipitation to the daylight hours on Monday which would pretty much put a stop to any meaningful accumulations.

 

Two possible scenarios still are in play for the immediate D.C. area (within one county of the District) – 1) no accumulation to perhaps an inch on grassy areas and 2) light accumulations of a few inches, mainly on grassy areas.  We continue to favor the first scenario as most of the models keep the surface temperatures above freezing through the event.  However,  if a period of heavier precipitation falls between midnight and 7 a.m. when temperatures are coldest, then the second scenario would be more correct.

Accumulations of a couple inches or so are most likely in northern Fauquier County, central Loudoun and central Frederick Counties and to the west.  Elevated areas towards the Blue Ridge above 1,000 feet are most likely to see amounts of perhaps 3-6 inches (or even a bit more above 2,000 feet).

Precipitation could start as early as the late afternoon hours Sunday in our western areas and overspread much of the region Sunday evening.  Precipitation may begin as rain or a rain/snow mix before perhaps changing over to mostly snow, mainly west of I-95.  Areas along and east of I-95 straddle the rain-snow line and may alternate between precipitation types.  During the day Monday, the rain-snow line will shift back towards the west, with most spots changing to rain before precipitation ends in the afternoon.

Steve Zubrick, Science Operations Officer at the National Weather Service in Sterling, seems to agree with our overall forecast ideas.  Here’s what he posted to Facebook:

A mix of rain and snow could start as early as Sun afternoon, but [surface] temps will be well above freezing. Similar to last weeks’ Mon storm, snow may fall at a brisk clip early Mon morning especially in the pre dawn hours, but with surface temps at or slightly above freezing, area roads in NoVA should be just wet so no problems expected (spring break for area schools anyway). Snow will mix with rain after 9am Mon and eventually change over to all rain east of the Blue Ridge by noon Mon. Perhaps a slushy accum on grassy surfaces of around an inch or so east of a Frederick MD-Leesburg- Warrenton VA line east to the I-95 corridor is possible. Little or no snow accum expected for DC.

We’ll keep you posted on any needed updates to the forecast throughout the weekend.

Also on Capital Weather Gang

D.C. area forecast: Warmer today before storm system approaches Sunday