Forecast Discussion for Willowsford Farm and vicinity from the NWS in Sterling, Virginia
000 FXUS61 KLWX 261412 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 912 AM EST Tue Jan 26 2021 .SYNOPSIS... Low pressure will pass through the area today. High pressure will briefly return Wednesday. An upper-level disturbance is expected to pass through the area Thursday morning while low pressure develops well southeast of the area. High pressure will return briefly Friday and Saturday before another storm system approaches for late in the weekend into early next week. && .NEAR TERM /THROUGH TONIGHT/... Temperatures are rising slowly but surely this morning. Have extended the Winter Storm Warning for Mineral, Allegany and Garrett Counties (as well as the Winter Weather Advisory for the eastern WV Panhandle and north-central MD) until 1 PM given continued drizzle and temperatures only slowly rising toward freezing. Also extended the Winter Weather Advisory until 11 AM for portions of northern Virginia where temperatures are hovering right around freezing. By this afternoon, temperatures should rise above freezing and any lingering precipitation should transition fully over to plain rain. The surface low pressure will pull off the eastern seaboard this evening. Dry conditions expected for most of our region this evening into early Wednesday with some upslope snow showers possible along and west of the Allegheny Front. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... High pressure will build to the northwest over the Great Lakes region and eastern Canada on Wednesday. A weak easterly flow will become light out of the northwest which will allow for a broken cloud deck to linger into Wednesday. Dry conditions are expected with afternoon temperatures warming into the 40s to lower 50s. An upper-level trough over the Plains will drive a surface low pressure system eastward into the southeastern U.S. on Wednesday. Models have trended southward with this system which has decreased the threat for snow over our region late Wednesday into early Thursday. We have kept the highest PoPs down in central Virginia and have at least slight chance PoPs everywhere by 12Z Thursday. If precipitation does move northward into our region, the precipitation will likely fall as a rain/snow mix to start and then quickly transition over to all snow Thursday morning. The Euro does try to bring in some snow showers Thursday morning to all of our region as the low pressure pulls northeastward off the eastern seaboard, but the NAM and GFS are drier. The high pressure off to the northeast will build into our region behind the exiting low pressure on Thursday. Dry and clear conditions are expected with the wind becoming northwesterly. Depending on the track of the low pressure, strong gusts of 30 to 40 mph will be possible near and east of the Blue Ridge and Catoctin Mountains, with the strongest wind focused over southern Maryland. Daytime temperatures will be much cooler in the mid to upper 30s due to strong cold air advection. Thursday overnight low temperatures will be chilly in the teens to lower 20s. && .LONG TERM /FRIDAY THROUGH MONDAY/... A reinforcing shot of cold air will cross the region Friday as a trough passes to the north. We wouldn`t rule out a few flurries or a snow shower with it, but mostly dry and brisk conditions are expected overall. High temperatures in the 30s will help Friday rank as one of the coldest so far in this otherwise mild winter. High pressure will nose southward over the region for Friday night through Saturday night with a cold but dry air mass and lessening winds. Radiational cooling should allow at least Friday night to drop near, or colder than, the coldest night so far this winter, but that`s not saying much given how little true cold we have seen. Low temperatures may be in the teens across much of the area, with high temperatures Saturday in the 30s once again. Depending on cloud cover, Saturday night could be similarly cold to Friday night, though increasing clouds ahead of an approaching storm system could keep it a bit milder. Models continue to indicate a storm system approaching from the south-central U.S. will move across the region in pieces Sunday into Monday. With cold air looking more plentiful at the start than it did last night, we may have a better chance at a widespread snowfall. Ensemble probabilities have definitely become snowier for Sunday, but it`s still 5 days out. That said, given our very limited winter weather last winter and so far this winter, anything more than an inch or two could become the snowiest storm since 2019 for much of our area. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... Drizzle and light rain, some freezing, continue across most terminals this morning, but should taper off by midday as temperatures rise and the causative low pressure moves away. IFR/MVFR will likely persist much of the day and possibly into tonight as there will not be much wind to mix things out. VFR conditions should return during the day on Wednesday but a surface low pressure system moving to the south of our region will bring another chance for wintry precipitation to the CHO terminal late Wednesday into Thursday. Clouds associated with this system will overspread all terminals and subVFR conditions will be possible into early Thursday morning. The main effect from this low pressure will be a strong gusty wind out of northwest on Thursday with the strongest winds affecting the I-95 corridor terminals. VFR conditions are expected Friday and Saturday, aside from the very low risk of a stray flurry or snow shower Friday. A blustery northwesterly wind Friday should be lighter than that on Thursday, and should lighten further on Saturday. && .MARINE... No Small Craft Advisories are expected through Wednesday at this time. A strong low pressure moving to our south will bring strong wind gusts of 25 to 35 knots Thursday into Friday. Small Craft Advisories are expected Wednesday evening through Thursday night with Gale Warnings possible. SCA conditions still likely Friday, but the wind should be notably lighter than Thursday. High pressure building just to the north should help the wind relax further on Saturday, decreasing the risk of SCA conditions. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Winter Weather Advisory until 1 PM EST this afternoon for MDZ003>006-008-011-503>508. Winter Storm Warning until 1 PM EST this afternoon for MDZ001- 501-502. VA...Winter Weather Advisory until 11 AM EST this morning for VAZ027-028-030-031-040-501-505. WV...Winter Weather Advisory until 1 PM EST this afternoon for WVZ051>053. Winter Storm Warning until 1 PM EST this afternoon for WVZ503- 504. MARINE...None. && $$ SYNOPSIS...JMG NEAR TERM...DHOF/JMG SHORT TERM...JMG LONG TERM...RCM AVIATION...RCM/DHOF/JMG MARINE...RCM/JMG
NWS LWX Office Area Forecast Discussion