Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 302000 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 300 PM EST Mon Nov 30 2020 .SYNOPSIS... Strong low pressure will move off to the northeast this evening. High pressure will gradually build over the area by Thursday morning. Another storm system may impact the area at the end of the week or early next week. && .NEAR TERM /THROUGH TONIGHT/... Severe wx threat is winding down and should be entirely over by 22Z/5PM EST. Low pressure is moving off to the northeast with cold front clearing the entire the area by 00Z tonight if not sooner. Conditions will improve east of the mountains, but over the mtns, sharply falling heights will result in crashing snow levels with any rain showers transitioning rapidly to snow showers early this evening. Winter Storm Warning remains in effect for Garrett County and Advisories for western Grant and western Pendleton Counties where significant snow accumulations are expected. Please refer to WSW for more details. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Cutoff upper low will cross the area tomorrow with strong DPVA over the area. This will result in mostly cloudy/cloudy skies and nearly steady temperatures in the mid 40s. Winds will remain brisk out of the WNW and gust to nearly 30 mph creating wind chills in the mid to upper 30s and much colder over the mountains. Snow showers will continue over the mountains through Tue night. Fair weather expected on Wed, but on the brisk side as upper low moves east and subsidence inversion strengthens. Winds could gust up to 30 mph with wind chills remaining in the 30s. && .LONG TERM /THURSDAY THROUGH MONDAY/... Quite the interesting and active pattern continues for the latter portion of this week into the weekend. Overall, guidance is in fairly good agreement in regards to the long term forecast. A retrograding low over northern Quebec persists while a double barrel upper level low induces a quasi-Fujiwhara effect over the Southern Plains. Slight ridging over the southeastern CONUS will keep surface high pressure just offshore Thursday; keeping the region dry. However, the upper level trough over Quebec will dive southward over the Ohio Valley just enough where it will pick up one of the upper level lows over the Southern Plains. As a result, a surface cold front will push through the region Friday into Saturday; reviving the risk for showers. A Rex Block will then develop over the western CONUS, which will amplify the upper level trough over the Eastern US. While the placement of the trough will keep our region dry under a strong NW flow, brisk conditions will likely return to the area for the weekend before another storm system possibly approaches early next week. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... Showers ending by 21Z or 22Z with cigs gradually improving to VFR by 00Z tonight, but BKN cigs 035-045 will persist overnight and part of Tue. Gusty W winds develop Tue with gusts to 25 kt. Fair weather Wed. VFR conditions are likely Thursday with high pressure offshore inducing a southerly flow. Sub-VFR possible by late Fri PM due to increasing chance for showers as the wind turns SE. && .MARINE... Gradient winds are diminishing, but showers and isolated t-storms may still pose a risk of 34kt or greater winds and isolated waterspouts. Winds dimnish overnight, but solid SCA conditions are expected on Tue. A light southwesterly wind is forecast Thursday as high pressure passes to the south, becoming southerly Thursday night into Friday as the high moves offshore. The wind may begin to increase as it turns southeasterly ahead of a low pressure system approaching from the Tennessee River Valley by late Friday. && .TIDES/COASTAL FLOODING... Moderate coastal flooding can`t be ruled out at Annapolis early this evening. Otherwise, high end minor flooding is expected. Raised CF.Y for Havre de Grace where observational trends suggest minor coastal flooding is likely. Could get close to minor at Straits Point in the next hour or two. Water level should begin to drop more rapidly late this evening and overnight as westerly flow develops. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Coastal Flood Advisory until 11 PM EST this evening for DCZ001. MD...Coastal Flood Advisory from 8 PM this evening to midnight EST tonight for MDZ508. Coastal Flood Advisory until 11 PM EST this evening for MDZ014. Winter Storm Warning from 1 AM Tuesday to 7 AM EST Wednesday for MDZ001. Coastal Flood Advisory until 10 PM EST this evening for MDZ011. VA...None. WV...Winter Weather Advisory from 4 AM to 7 PM EST Tuesday for WVZ501-505. MARINE...Small Craft Advisory from 6 PM to 10 PM EST this evening for ANZ530>532-535-536-538>542. Gale Warning until 6 PM EST this evening for ANZ530>543. Small Craft Advisory from 6 PM this evening to 6 AM EST Tuesday for ANZ533-534-537-543. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...MSS AVIATION...MSS/LFR MARINE...MSS/LFR TIDES/COASTAL FLOODING...LFR is the U.S. government's official web portal to all federal, state and local government web resources and services.