Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 241325 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 925 AM EDT Sat Mar 24 2018 .SYNOPSIS... Weak high pressure will be in control of the area today. Low pressure will move across the southeast states tonight. High pressure builds again over the area Sunday through Monday night. A cold front will cross the area late next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Low pressure will track into the Tennessee Valley while surface high pressure remains over our area. There will be some high and mid-level clouds ahead of this system, especially across southwestern portions of the CWA. The low should remain far enough away from our area for dry conditions to persist. More chilly conditions are expected for this time of year with max temps in the upper 40s and lower 50s for most areas. Do have max temps a little chillier across our extreme southwestern portion of the CWA where cloud cover is expected to be a little more widespread. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... Low pressure will pass by to the south tonight and high pressure over New England will build south into our area overnight. The track of the low should be far enough south to keep dry conditions for most of the area. A period of snow is possible across our extreme southwestern portion of the CWA...over southern portions of Highland, Augusta and Nelson Counties. Even across these areas, precipitation amounts are expected to be light (if any) so any accumulation would be around one inch or less. The latest trend in guidance has shifted the track of the low farther south, which increases confidence for little or no snow accumulation. However, it is a tight gradient and any shift to the north with would have a significant impact on the forecast for those areas. High pressure will continue to build south into our area for Sunday. An upper-level disturbance will drop south from New England int eastern Pennsylvania and New Jersey. This could trigger an isolated snow shower across our eastern areas but confidence is low at this time. No accumulation is expected. && .LONG TERM /MONDAY THROUGH FRIDAY/... Strong high pressure 1040+mb centered over northern New England Tue morning will be shifting east and weakening over the area Tue through Thu. Meanwhile, low pressure will track from the central Plains to the Great Lks with some moisture advancing northeastward ahead of the associated front. Rain showers could start making an appearance in our western areas as early as Tue morning with the risk slowly increasing through mid week. By Thu, the risk of showers increases significantly as moisture deepens and cdfnt approaches. The front will be slow to cross the area as it will be encountering a strong mid-upper level ridge offshore. By 12Z Sat, most ensemble members show front having cleared the area with precip chances decreasing Fri afternoon on but not completely out of the fcst. High pressure will be building over the area for the second half of next weekend. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... High pressure will remain over the area today and VFR conditions are expected. Low pressure will pass by well to the south tonight and high pressure over New England will build into our area after midnight. A period of snow may approach KCHO but latest thinking is that it will remain to the south. North to northeast winds may gusts around 15 to 20 knots overnight from the pressure gradient associated with the high to our north building south into our area. High pressure will return for Sunday through Sunday night with more VFR conditions. No flight restriction expected Monday or Tuesday. Risk of showers Tue afternoon through Wed, but flight restrictions are not anticipated. && .MARINE... A Small Craft Advisory remains in effect for the middle portion of the Bay and lower Tidal Potomac River this morning. Low pressure will pass by to the south tonight and a pressure surge ahead of building high pressure will cause wind gusts around SCA criteria later tonight through Sunday night. Possible SCA conditions Thu, otherwise winds 10 kt or less Tue through Wed night. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 6 AM to 6 PM EDT Sunday for ANZ530>543. Small Craft Advisory until 11 AM EDT this morning for ANZ533- 541-542. Small Craft Advisory until 2 PM EDT this afternoon for ANZ534- 543. && $$ SYNOPSIS...BJL/LFR NEAR TERM...BJL/KLW SHORT TERM...KLW LONG TERM...LFR AVIATION...BJL/LFR/KLW MARINE...BJL/LFR/KLW is the U.S. government's official web portal to all federal, state and local government web resources and services.