Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 231910 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 310 PM EDT Wed May 23 2018 .SYNOPSIS... High pressure will build into the region from the northwest late this afternoon through Thursday night. This high should move offshore Friday. Moisture will increase ahead of a low pressure system over the weekend into early next week. && .NEAR TERM /THROUGH THURSDAY/... A shower in spots across southern Maryland, the central Chesapeake Bay, or parts of the Virginia Piedmont is possible as the cold front pushes across these areas later this afternoon. A rumble of thunder cannot be ruled out. Any activity should be very isolated and brief. High temperatures will be in the lower to middle 80s for most locations. High pressure will build in from the northwest tonight. Dry conditions with mainly scattered mid-level clouds expected tonight. Low temperatures will drop down into the upper 50s to near 60 over the eastern half of our region, while lows should reach the lower 50s over the western half of our region. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... The center of high pressure will move overhead later in the day Thursday into Thursday night before moving offshore Friday. In the meantime, we can enjoy dry conditions Thursday into Friday. As we get into late Friday and Friday night and looking out west into the Potomac Highlands, we could encounter a shower or two; otherwise, dry conditions for all. Dewpoint temperatures will be in the lower 50s Thursday versus the lower 60s that we experienced this afternoon. This should make conditions a little more comfortable. Temperatures both Thursday and Friday will reach the lower to middle 80s with increasing humidity expected Friday around the back side of the area of high pressure. Low temperatures Thursday night expected to be in the middle 50s to upper 50s. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Saturday into Sunday, a high pressure system will be located off the Atlantic coast near Bermuda. This will lead to a south to southwesterly flow which will work to funnel tropical moisture into the region. Temperatures rising up into the mid to upper 80s on Saturday and Sunday coupled with tropical moisture could lead to the formation of convective showers and thunderstorms which may produce heavy showers. Monday through Tuesday, a weak boundary will approach from the west. A south to southwesterly flow will continue the flow of tropical moisture into the region. High temperatures will be in the low to mid 80s on Monday. The approaching frontal boundary on Monday will act as a convergence zone which may allow for some forcing to cause the formation of storms and showers. The combination of tropical moisture and the boundary will lead to a chance for thunderstorms and showers on Monday. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... VFR conditions late this afternoon through Friday night. Winds have become northwesterly and gusting over 20 knots at times behind the cold front at all terminals, except for CHO, where winds are generally still light out of the north. Expect winds to diminish tonight as high pressure builds in over the region. Saturday, the combination of tropical moisture and rising temperatures up into the mid 80s will lead to an environment that could be conducive for the formation of disorganize thunderstorms and heavy showers. && .MARINE... A small craft advisory is in effect through late this afternoon as we look at a cold front passing over the waters of the Potomac River and Chesapeake Bay. For the most part, wind gusts have been between 17 and 22 knots with gusts as high as 26 knots in a few locations. High pressure will build across the waters tonight and Thursday before moving offshore on Friday with light winds. Some of the wider waters of the Bay may come close to SCA criteria Friday night as southerly flow increases on the back side of the high. On Friday, winds will be out of the south which may lead to the need for a small craft advisory. Skies should remain most clear with mild temperatures in the upper 70s to lower 80s. On Saturday, the influx of tropical moisture will combine with higher temperatures to allow for the formation of disorganized showers and thunderstorms. && .TIDES/COASTAL FLOODING... Tidal anomalies will continue to decrease this afternoon as northwesterly winds develop behind a cold front. However, water levels remain more elevated around DC given some freshwater input, with the current high tide barely coming in below flood stage. This situation may repeat itself during the morning high tides the next couple days. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ530>543. && $$ SYNOPSIS...KLW NEAR TERM...KLW SHORT TERM...KLW LONG TERM...JMG AVIATION...KLW/JMG MARINE...KLW/JMG TIDES/COASTAL FLOODING...KLW is the U.S. government's official web portal to all federal, state and local government web resources and services.