Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 040737 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 337 AM EDT Sat Apr 4 2020 .SYNOPSIS... Weak high pressure will build in from the Ohio Valley through Sunday morning. A weak cold front will move in Sunday night before becoming diffuse on Monday. A low pressure system will approach from the midwest on Wednesday. && .NEAR TERM /THROUGH TONIGHT/... A mid-level circulation is clearly evident on all three GOES-16 water vapor channels and likely extends from 700 mb up to the 300 mb level. This circulation is significantly stronger than what models are initializing early this morning. A few showers have been observed over central PA this morning and are working their way southward. The mid-level circulation is expected to continue pushing southward this morning and move south of the area by 18Z. Expect increasing cloudiness with lowering cigs and the risk of a few sprinkles or very light showers between 09Z- 15Z for areas in MD east of Rt 15 and I-95. It will be about 5 degs cooler than yesterday with highs around 60 or lower 60s. We`ll gradually lose the low clouds overnight, but high clouds will start arriving at the same time. Overall, mostly cloudy skies expected tonight. Lows will be in the mid 40s. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Few-sct showers are possible Sunday into Sun evening as weak cold front approaches from the west and eventually crosses the area. The front is expected to push south of the area late Sun night and then become diffuse Monday. It should be on the warm side with ridge axis overhead. Showers may enter the fcst area again late Monday night and Tue as a weak area of low pressure forms along a developing frontal zone attached to low pressure over the upper Midwest. && .LONG TERM /TUESDAY THROUGH FRIDAY/... The subtropical jet is forecast to move northward into the mid- Atlantic region on Tuesday while a weaker upper level jet drops southward from the Great Lakes region. This will lead to upper level ridging over the central plains and parts of the midwestern US through Wednesday. Shortwaves are forecast to move along this ridge and down into our region on Wednesday. A surface low associated with these disturbances will move to our north bringing a chance for showers Tuesday and Wednesday. Precipitation will likely be limited by the lack of good forcing and a general westerly flow transporting in a drier downsloping air. Temperatures during this period should slowly trend upwards into the 70s with overnight lows in the 40s and 50s. A strong upper level low is forecast to drop southward into the central US from the Canada on Thursday. A surface low associated with this upper level low will move through the Great Lakes region and eastern Canada. A cold front will approach and move through our region on Thursday bringing another chance for rain to our region. There remains some uncertainty on the strength and timing of an upper level jet which could help influence the location and amount of precipitation that our region receives. The front should be through our area by Friday morning but the low to our north is forecast to occlude west over the NE US which could bring a back end chance for showers again on Friday. Behind the frontal passage, high pressure builds over our region on Friday along with a cooler air mass which could bring a spring chill to our area. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... Increasing clouds today with lowering cigs but still VFR. Low clouds start lifting tonight. Few showers are expected Sun with a frontal passage expected Sunday evening along with shifting winds. Front becomes diffuse Monday. No sig wx Mon and Tue. Showers will be possible Tuesday and Wednesday. Winds will be mainly out of the west with periods of variable winds. VFR conditions expected at this time for Tuesday and Wednesday. More widespread rain expected Thursday which may lead to subVFR conditions. && .MARINE... Winds will gradually diminish through early this afternoon, then light and variable winds tonight through at least the middle of next week. No hazards expected. && .TIDES/COASTAL FLOODING... Water levels are expected to rise today into Sunday morning with potential for moderate coastal flooding at Straits Point and possibly Annapolis beginning tonight and continuing through Sun night. Advisories may also be needed for today. At the very least, will likely be issuing a Coastal Flood Watch for St. Mary`s County before the end of my shift valid for tonight through Sunday evening. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...JMG AVIATION...LFR/JMG MARINE...LFR/JMG TIDES/COASTAL FLOODING...LFR

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