Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
061 FXUS61 KLWX 231857 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 157 PM EST Sat Nov 23 2024 .SYNOPSIS... High pressure briefly returns Sunday before another front pushes through Monday into Tuesday. A more potent front and low pressure system look to arrive for the Thanksgiving holiday period. && .NEAR TERM /THROUGH TONIGHT/... Upslope shower activity across the Alleghenies will slowly decrease through the evening as the upper level low exits off the northern New England coast. Most of the precipitation has transitioned to rain as of 130 PM, but a few flakes or patchy areas of freezing drizzle are possible across the highest elevations. Breezy conditions will remain through the evening as the pressure gradient remains tight. This will result in continued wind gusts of 20-35 mph (up to 45 mph along the higher ridges). Lows tonight will fall back into the mid to upper 30s for most, with 20s in the mountains. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... High pressure briefly returns Sunday before moving off the southeast U.S Monday. This will bring dry conditions along with moderating temperatures. Highs Sunday will push into the low to mid 50s with 40s over the mountains. Lows Sunday night will fall into 30s. Dry conditions will continue through the first half of Monday. An area of low pressure and it`s associated cold front are expected to cross the region late Monday into early Tuesday. Guidance continues to show rain showers overspreading the Alleghenies Monday evening with the showers spreading east overnight. Light QPF amounts are expected with this system, generally a tenth of an inch or less aside form the Alleghenies. The moderating trend continues on Monday with temperatures in the upper 50s to near 60 for most. Mostly sunny skies to start will give way to mostly cloudy skies by the late afternoon/evening ahead of the approaching low. Lows only fall into the 40s to near 50 for most Monday night. && .LONG TERM /TUESDAY THROUGH SATURDAY/... If it hasn`t already, the cold front will be pushing east of the area Tuesday morning, with any shower chances quickly ending. An exception may be the upslope areas in the Alleghenies, where a brief changeover to snow could occur before precipitation ends around midday. Gusty west winds will follow the front, but the downsloping flow will allow high temperatures to reach the lower 60s again in some of the piedmont and coastal areas. A fairly flat upper level pattern will result in an area of high pressure moving overhead by Wednesday morning and quickly moving off to the east Wednesday night. Temperatures are forecast to be slightly below normal during this time. The next shortwave will quickly approach from the Rockies by early Thursday, with surface low pressure eventually strengthening toward the east coast. While precipitation is looking increasingly likely at some point between late Wednesday night and Friday morning, there remain some uncertainties with the track of the low and associated thermal profiles. Any sort of wintry weather looks to be most likely confined to the Allegheny and Potomac Highlands, although there are non-zero probabilities across much of the climo-favored areas northwest of I-95. Thanksgiving will likely be chilly and rainy for much of the area either way. As long as the system stays progressive, Friday and Saturday are forecast to dry out east of the mountains with a gusty northwest wind and temperatures trending further below normal. Meanwhile, accumulating upslope snow will commence west of the Allegheny Front. Confidence remains low on amounts this far out. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR conditions are expected to continue at most terminals through Monday. Brief periods of MVFR cigs are possible through this evening as the upper level low slowly exits the region. Wind will remain the main hazard today due to the tight gradient overhead. Expect sustained west to northwest winds at 10-20 kts with gusts of 20-30 kts through this evening. West to northwest winds will decrease tonight into Sunday with gusts 15-20 kts. Potential for sub-VFR conditions arrive Monday night into Tuesday as another low pressure system crosses the region. A few showers will accompany the low and it`s associated front leading to to some cig/vsby restrictions at times. Winds will turn to the south Monday at 5-15 kts. Winds increase late Monday night into Tuesday as the front passes. After frontal passage Tuesday morning, west winds will gust 20-30 kt until sunset. No significant weather is forecast Tuesday night and Wednesday with high pressure. The next low pressure system will arrive by Thanksgiving with rain and sub-VFR conditions. && .MARINE... High end SCA conditions with gusts between 25 to 30 kts out of the west/northwest are expected over all waters through early Sunday morning. Have extended SCAs through midday Sunday across the the Chesapeake where winds are slow to taper. Sub-SCA level winds are expected late Sunday afternoon through Monday as high pressure builds nearby. Winds become southerly Monday as high pressure moves offshore. Southerly channeling may develop across the wider waters of the Chesapeake resulting in SCAs. A cold front may bring a line of gusty showers across the waters late Monday night into Tuesday morning. SCAs are most likely, but could see a few gusts near gale force. After a cold front crosses Tuesday morning, winds will turn to the west and gust 20-30 kt through the day. While winds will gradually decrease Tuesday night into Wednesday morning, advisory conditions will likely linger along the bay. High pressure will bring lighter winds on Wednesday. The next low pressure system will approach Thursday, but its track and strength remain uncertain at this time. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Small Craft Advisory until 1 PM EST Sunday for MDZ008. VA...None. WV...None. MARINE...Small Craft Advisory until 1 PM EST Sunday for ANZ530>534- 538>543. Small Craft Advisory until 7 AM EST Sunday for ANZ535>537. && $$ SYNOPSIS...EST NEAR TERM...CPB SHORT TERM...CPB LONG TERM...ADS AVIATION...ADS/CPB MARINE...ADS/CPB