Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 021020 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 520 AM EST Tue Mar 2 2021 .SYNOPSIS... High pressure over the Great Lakes will build overhead through tonight. Low pressure will pass well to the south Wednesday. A reinforcing cold front will cross the area Wednesday night. Canadian high pressure will build toward the region Thursday through Saturday, then move offshore early next week. && .NEAR TERM /THROUGH TONIGHT/... High pressure over the Great Lakes will build overhead today. Stratocumulus clouds banking up against the Allegheny Front (and in some instances spilling east of the mountains) should erode as drier air works in this morning. The wind will start out gusting 20 to 30 mph out of the northwest this morning, then diminish after noon as the high pressure center builds overhead. Temperatures today and tonight are expected to be about 5 to 10 degrees below normal. When factoring in the wind first thing this morning, it may feel like it`s in the teens and 20s. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Low pressure developing over the northeastern Gulf of Mexico is forecast to track across northern Florida and southern Georgia, then into the Atlantic Ocean on Wednesday. This should keep the northern extent of any precipitation and most clouds from near the North Carolina/Virginia border southward. A cold front is forecast to drop southward out of across the area Wednesday night. A modest uptick in cloud cover and a few sprinkles or flurries are possible. The wind will then shift to the north/northwest and increase through Thursday, reinforcing below normal temperatures. && .LONG TERM /FRIDAY THROUGH MONDAY/... Canadian high pressure will build overhead Friday through Friday night bringing a continuation of dry and chilly conditions for this time of year. Low pressure in the southern stream of the jet will pass by to the south Saturday, and as of now it is expected to remain far enough to the south so that dry and chilly conditions will persist. We will have to keep an eye on some northern stream energy that will pass through our area Saturday night. If the energy is strong enough, it may cause a few snow showers despite limited moisture. However, confidence for that to occur is too low to mention in the forecast at this time. The high pressure will gradually move offshore Sunday through Tuesday of next week; a return flow should allow for a moderating trend in temperatures (especially by Tuesday of next week where temperatures may be several degrees above climo). && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... VFR expected thru Sat. NW G20-25kt thru 18z, diminishing and becoming S/SW tonight. W flow 5-10kt Wed, then N/NW 10-15G25kt thru the end of the week. && .MARINE... High pressure over the Great Lakes will build overhead through tonight. Northwesterly wind gusts of 20 to 25 knots are expected through early afternoon before the high pressure center moves overhead. A lighter southerly to westerly wind is forecast tonight into Wednesday, though a period of southerly channeling likely results in gusts to around 20 knots late this evening into Wednesday morning. Gusty northerly to northwesterly winds are forecast to return behind a reinforcing cold front Wednesday night through much of the later part of the week. && .HYDROLOGY... The excess runoff from previous rainfall has entered the Potomac River Basin. Flooding is expected across portions of the Potomac River Basin through at least tonight before water levels subside Tuesday and Wednesday. An extended period with several days of dry weather is likely to persist for the rest of this week into early next week. && .TIDES/COASTAL FLOODING... Runoff of rain and snowmelt from a couple days ago is heading down the Potomac River, and may cause near minor flooding along the shoreline of Washington DC later this morning. Minor flooding appears more likely for the tide cycles this evening and again Wednesday morning. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 3 PM EST this afternoon for ANZ530>543. Small Craft Advisory from 10 PM this evening to 6 AM EST Wednesday for ANZ531>533-537-539>541. Small Craft Advisory from 10 PM this evening to noon EST Wednesday for ANZ534-543. && $$ SYNOPSIS...BJL/DHOF NEAR TERM...DHOF SHORT TERM...DHOF LONG TERM...BJL AVIATION...BJL/DHOF MARINE...BJL/DHOF HYDROLOGY...BJL TIDES/COASTAL FLOODING...DHOF is the U.S. government's official web portal to all federal, state and local government web resources and services.