Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
544 FXUS61 KLWX 111847 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 247 PM EDT Sat May 11 2024 .SYNOPSIS... Low pressure moving across the area will bring showers and a few thunderstorms late this afternoon into tonight. A lingering upper level disturbance may allow showers to persist into Sunday along with cool temperatures. Drier conditions return with brief high pressure Monday. A slow moving low pressure system will bring more unsettled weather Tuesday into Wednesday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... An upper trough and associated cold front to our west will quickly move across the area through early evening. The line of moderate to heavy showers has reached the western CWA as of 2 PM. Expect quick progression across the area, with approximate time of precip reaching the Shenandoah Valley between 3-5PM, between the Blue Ridge and I-95 from 4-6PM, then east of I-95 to the Eastern Shore from 5- 7PM. The moderate rainfall is most likely north of US-50, with mostly light showers to the south. Once this initial line moves through, skies will clear up again, with those west of US-15 likely to see more sun early this evening. Temperatures are currently in the 60s, and should fall back to 50s in/behind the precip. Scattered showers continue behind this main line, though given their fast motion not expecting any particular area to see more rain this evening. Cannot rule out a stray thunderstorm or two, though chances right now look to be very low. Showers slowly depart to the east overnight, as most of the region returns to dry conditions by Sunday morning. Low temperatures generally drop to the upper 40s to low 50s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... The aforementioned cold front will move east of the area Sunday morning, though some residual moisture on the backside of the broad low could bring some on-and-off showers along/north of US-50 through Sunday afternoon. Conditions dry out Sunday evening as high pressure builds in from the west. Highs generally be in the 60s, with some low 70s possible in Central VA Sunday afternoon. Overnight lows mostly in the 40s to low 50s. For Monday, expect dry conditions as high temperatures reach back to the mid to upper 70s. An approaching upper disturbance looks to hold off until late Monday night, when scattered showers move into areas west of the Blue Ridge. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Monday looks to be our driest day of the next 7 days with mid level ridging overhead and surface high pressure sitting just to the south of the region. This will yield a seasonable Spring day with high temperatures in the mid to upper 70s and overnight lows in the 50s. Unfortunately, the dry time will be brief as an upper trough develops in the lee of the Rockies, and deepens as it tracks eastward from the mid-Mississippi River Valley during the middle part of workweek. Meanwhile, high pressure will shift off the VA/NC coast Tuesday into Wednesday allowing for south to southeasterly return flow to ensue. This will allow Atlantic and eventually Gulf of Mexico moisture to increase across the region yielding daily isolated to scattered chances for showers and thunderstorms. Uncertainty remains in the placement and timing of the heaviest precipitation with a focus midweek (late Tuesday into Wednesday). This is due largely in part to a warm frontal boundary that will be lifting northward into the region. The severe weather threat appears to be minimal with richer moisture suppressed toward the Gulf Coast. Locally heavy rainfall is possible especially during the midweek timeframe due to increasing moisture and the placement of a warm front draped nearby. High temperatures will remain at or slightly below normal midweek. Expect highs in the low to mid 70s Wednesday and mid to upper 70s Thursday. Lows will fall into the mid to upper 50s. Low pressure and it`s resulting trough depart offshore Thursday into Friday. A cold front will quickly follow bringing in drier air as high pressure builds over eastern Canada. The dry time once again will be short lived as another trough and area of low pressure approach from the Ohio River Valley. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... A weak cold front and associated line of light to moderate showers will quickly move across the area this afternoon into early evening. Thunder has been removed from all the TAFs for this initial surge as precip to the west has remained stratiform and is expected to stay the course as this system moves across the area. Any moderate rain could result in MVFR conditions for an hour or two. Once this initial push of rain moves through, scattered showers are expected this evening, thus VCSH was added to most TAFs to account for this. Thunder is not likely this evening given the decrease in instability from loss of daytime heating and stabilizing effect of the earlier rainfall. The cold front sweeps through early Sunday morning, causing winds to shift northwest behind the front. Gusts to around 20 knots are likely from late morning through the afternoon Sunday. VFR conditions expected through Monday as high pressure returns. VFR conditions are expected with high pressure nearby. Sub VFR ceilings along with a showers and a few thunderstorms are possible Tuesday and Wednesday as an area of low pressure and front push into the region. Shower and thunderstorm chances look to linger Thursday with high pressure briefly returning Friday. South to southwesterly winds are expected Monday before switching to the south and southeast Tuesday and Wednesday. Gusts of 15 to 20 kts can be expected each afternoon. && .MARINE... A line of widespread showers will quickly cross the waters late afternoon into early evening. No thunderstorms are expected with this initial precipitation. Once this moves through, scattered showers are possible this evening, and while not likely, any strong shower that develops could produce wind gusts to around 30 knots. Winds increase this evening into part of tonight just ahead of the approaching cold front. A Small Craft Advisory is in effect for the waters of the Chesapeake Bay and Lower Tidal Potomac. Winds should diminish late tonight. Winds turn northwest behind the cold front Sunday morning, and could gust to SCA levels for a few hours during the afternoon. Winds diminish Sunday night into Monday as high pressure builds into the region. SCA conditions will likely continue Monday, Tuesday, and Wednesday as low pressure approaches from the south and high pressure pushes offshore. South to southeasterly winds will gusts up to 20 kts each day with the potential for a few thunderstorms on both Tuesday and Wednesday afternoon/evening. && .TIDES/COASTAL FLOODING... Additional periods of coastal flooding is possible tonight, especially at sensitive locations in Annapolis, Straits Point, and DC SW Waterfront. Afterwards, water levels should drop off Sunday as northwest flow kicks in across the area. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Coastal Flood Advisory until 1 PM EDT Sunday for MDZ014. Coastal Flood Advisory until 9 AM EDT Sunday for MDZ017. Coastal Flood Advisory until 4 PM EDT this afternoon for MDZ508. VA...None. WV...None. MARINE...Small Craft Advisory from 8 PM this evening to 4 AM EDT Sunday for ANZ530>534-537-538-543. && $$ SYNOPSIS...KRR NEAR TERM...KRR SHORT TERM...KRR LONG TERM...LFR AVIATION...KRR/LFR MARINE...KRR/LFR TIDES/COASTAL FLOODING...KRR/LFR