Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 290824 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 424 AM EDT Sun Mar 29 2020 .SYNOPSIS... A warm front will try to lift north across the region today before a cold front moves through from the west by this evening. High pressure will be in control Monday into Tuesday. A low pressure will then approach from the southeast U.S. Tuesday night before departing off the mid-Atlantic coast on Wednesday. High pressure will return for the end of the week. && .NEAR TERM /THROUGH TONIGHT/... Frontal boundary still remains wedged south of our area this morning with fog being observed throughout our CWA. Dense Fog Advisory is in effect for western areas and this may need expansion as we approach dawn. The front is associated to a low pressure system that is currently over the Mid-West and will be moving this morning into the Great Lakes region. This will lift this boundary as a warm front this morning and pushing a cold front into our region this afternoon. Low clouds and fog will remain north of the boundary this morning with conditions improving behind it as it lifts north across our area, though it will struggle to get to DC and may never make it to Baltimore. Southerly flow will settle behind this boundary advecting a more unstable air mass into our area as sky cover diminishes. Dew points will rise into the 60s over this sector and ahead of the approaching cold front. Will have decent shear in place, CAPE values up to 1000 J/kg west of the Blue Ridge, and generally up to 1500 J/kg east of it, and DCAPE values between 500 and 1000 J/kg. Also, guidance suggests there will be a weak surface low developing over our area this afternoon. Mid-level dry air and a low level inversion could inhibit thunderstorm development, but considering all ingredients in place, a few thunderstorms could still develop (some supercell potential), which is supported by some high res guidance. Main threat will be strong winds and large hail, but an isolated tornado cannot be totally ruled out, particularly if cells reach the vicinity of the warm front. Timing looks like it will be between 18 and 20Z west of the Blue Ridge, and 20 to 23Z east of it. The cold front will be out of the Mid-Atlantic in the evening and high pressure will build from the southwest overnight as deep low pressure slowly moves east just north of our region, and another low intensifies offshore. Dry conditions are expected Sunday night with temperatures in the upper 40s and upper 50s under westerly flow. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Dry conditions are expected on Monday with gusts between 15 and 25 knots. Cold air advection due to westerly flow will allow our high temperatures to be about 10 degrees cooler than Sunday for most of the area (areas near and northeast of Baltimore being the exception). Dry conditions will continue Monday night with lows in the 40s across most our our area and some low 30s across the Potomac Highlands. Low pressure will develop Monday night over the ArkLaTex region and will move east across the SE CONUS. The low will move south of region Tuesday into Tuesday night area, but how much of the precipitation from this system reaches our region is still questionable. High temperatures Tuesday will be in the 40s and 50s across our CWA. Low temperatures will be in the 30s and 40s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Low pressure will be passing east off the coast on Wednesday to our south. Upper level trough axis may help some showers linger, but overall drying trend is likely. Cool air pushing south with the northerly flow on the back side of the low will keep temps cool, with highs in the low-mid 50s overall. Beyond Wednesday, the weather looks significantly quieter than it did last night, with high pressure dominating through the period. This will allow milder weather than previously expected to dominate, with temperatures creeping a bit back above normal by Saturday. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... LIFR to IFR conditions are observed across the terminals this morning. This is expected to continue through this morning as we continue to be wedged north of a front. As this front pushes north this morning conditions should improve at CHO earlier then gradually improving further NE and becoming VFR this afternoon; the struggle to improve likely takes longest at BWI/MTN. A few isolated thunderstorms are possible this afternoon as a cold moves across our area, so a few restrictions are possible at times. VFR conditions continue Sunday night into Monday night with gusty winds on Monday. A low pressure could bring rain showers on Tuesday. Lingering rain showers could cause sub-VFR conditions at times Wednesday, but VFR should return Wednesday night and Thursday as drier air returns under high pressure. && .MARINE... Winds below criteria at this time. Expect them remain like this for the rest of today and tonight, but a few gusts associated to thunderstorms over the waters cannot be rules out this afternoon. Winds will increase on Monday and a SCA will be needed. Winds will remain below criteria Monday night into Tuesday. As a low passes south Tuesday night into Wednesday, SCA gusts will be possible. Winds likely relax by Thursday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...Dense Fog Advisory until 9 AM EDT this morning for VAZ025>031- 501-504>506. WV...Dense Fog Advisory until 9 AM EDT this morning for WVZ050>053- 055-506. MARINE...None. && $$ SYNOPSIS...IMR/RCM NEAR TERM...IMR SHORT TERM...IMR LONG TERM...RCM AVIATION...IMR/RCM MARINE...IMR/RCM is the U.S. government's official web portal to all federal, state and local government web resources and services.