Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 291426 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1026 AM EDT Wed Jun 29 2016 .SYNOPSIS... High pressure will build over the area today. A warm front across Gerogia will lift north Thursday into Friday. A cold front wil move into the region Friday night. A frontal boundary is expected to hover over the Mid Atlantic Sunday and Monday. && .NEAR TERM /THROUGH TONIGHT/... High pressure over WI will build eastward into the region. A decent shortwave will round the base of an upper level trough, which combined with moderate instability, could trigger isolated showers/thunderstorms late in the day. These will diminish after sunset, with dry weather expected tonight. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... The latest model suite continues to suggest that the boundary to our south will then slowly lift north Thursday night into Friday as the surface high exits this area. With the boundary placed just to the south, could see isolated showers and thunderstorms mainly over southern fringes of the CWA during the day, then increasing to the north Thurs night as the front lifts northward. Southerly flow increases during this time, aiding in both warm air and moisture advection. Models suggesting a bulls eye of instability mainly east of the Blue Ridge and south of the immediate DC Metro area, so will maintain the chance PoPs there. Right now the best chance for any stronger storm looks to be south of the area, closer to the boundary and where there is stronger deep layer shear, but cannot rule out a stray stronger storm moving into the southern portions of the area Thurs evening. Precip ongoing Thurs night, though shifting more to the east and impacting mainly the eastern half of the CWA on Friday. Instability not as impressive as the previous day, but with the approaching cold front, do see higher deep layer shear values. Will continue with the chance for thunderstorms and then showers through Friday night. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Latest guidance suggests that cold front will have sufficient push to clear most if not all of the forecast area by Saturday morning, and remain to the south through Sunday. If that were to hold, then the area would have a dry weekend...both in terms of precipitation and humidity. May still hedge bets a pinch, as this is the first cycle suggesting something this definitive (although the 28th 12z cycle did start the trend). The stalled frontal boundary will start to drift northward again as a warm front on Monday. As a result, the corridor of potential thunderstorms will shift north across the area as well, with a focus on Monday afternoon and evening. This pattern likely will continue into Tuesday, as there will be no catalyst to dislodge the stalled frontal boundary at that time. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... VFR conditions for the TAF period. VFR conditions Thurs and Friday outside of any thunderstorms. At this time, there are no forseen flight restrictions for Saturday or Sunday. A frontal boundary will linger south of the terminals, so a change in position would result in a more pessimistic forecast. && .MARINE... Sub-SCA conditions on all waters through Friday. Thursday evening and during the day Friday thunderstorms may impact the waters, especially the lower Chesapeake Bay. At this time, winds are not anticipated to exceed Small Craft Advisory thresholds through this weekend. However, that will be contingent on the strength and progress of a cold front clearing the waters. If it is well- defined enough and far enough south, then mixing would be favorable in northwest flow to have some gusts coming close during the afternoon. Not enough certainty to include in forecasts right now, but it`s certainly something to keep in mind. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ UPDATE...WOODY! PREVIOUS...APS/HTS is the U.S. government's official web portal to all federal, state and local government web resources and services.