Area Forecast Discussion
Issued by NWS Wakefield, VA

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487 FXUS61 KAKQ 251517 AFDAKQ Area Forecast Discussion National Weather Service WAKEFIELD VA 1117 AM EDT Sat Mar 25 2017 .SYNOPSIS... High pressure remains offshore the southeast coast through Monday. A weak frontal boundary drops south to the Delmarva Sunday morning before lifting back to north Sunday night and Monday. A cold front crosses the region Tuesday night. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Late morning analysis indicates surface high pressure centered well off the SE CONUS coast, with WSW flow aloft. Warm conditions prevail with temperatures averaging from the mid 60s to around 70 F as of 15Z/11 am. Skies are free of low-mid clouds but a fair amount of high clouds are streaming across the area so will keep sky cover in grids of 30-50% today leading to partly sunny wording for most areas. SW winds will avg 10-15 mph with gusts to 20-25 mph but still may see the winds on the eastern shore weaken enough to allow the direction to back to the S or SSE along the coast this aftn (which will allow readings to be steady or even fall a few degrees there). Dewpoints noticeably higher today than on Fri...mainly will average from the u40s- l50s. Highs this aftn to avg in the upper 70s to around 80 F west of the Bay to the lower-mid 70s closer to the coast (and locally in the 60s immediate coast of the eastern shore). && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... Remaining dry/mild tonight ahead of low pres lifting ENE from the mid MS Valley into the wrn OH Valley. A weak sfc boundary will settle over the ern shore by late tonight resulting in light onshore winds and possible BKN ST. Otherwise...S winds will prevail under mainly BKN-OVC CI. Lows m-u40s on the ern shore to the l-m50s elsewhere. Weakening low pres (sfc-aloft) will continue to track NE the Great Lakes Sun-Sun night...pushing a weak low level boundary into/across the FA. Only SLGT forcing aloft w/ this system...which will likely limit pcpn coverage. Otherwise...VRB clouds and mild w/ PoPs mainly confined to I 95 on W (20-30%) by late Sun afternoon/Sun night. Highs Sun from the l-m60s along the coast/on the ern shore to the l-m70s inland (in VA/NE NC). Lows Sun night in the u40s- around 50F on the ern shore to the l-m50s elsewhere. Initial system lifts into/through New England Mon...leaving FA w/ continued mild/warm conditions as hi pres (sfc-aloft) remains invof SE CONUS coast. VRB clouds Mon w/ PoPs mainly aob 20%. Highs mainly in the 60s on the ern shore to the l-m70s elsewhere. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Medium range period will remain mild, courtesy of warm southerly flow from lingering high pressure just offshore of the mid-atlantic coast. Other main weather feature of note will be a rather progressive mid-level shortwave traversing the western/central CONUS late Sat-Monday, before lifting E-NE across the mid-South toward the local area on Tuesday. High end chance POP remains in place for showers and sct T-Storms. While the system will be weakening, given decent instability and favorable diurnal timing, will continue thunder wording for all but far NE zones (later timing). Shortwave ridging behind the wave will bring slightly cooler, albeit still mild, and drying wx Wed and Thu. Forecast highs mainly in the 60s to near 70 far north and along the immediate coast...70s to near 80 west of the Bay on Tuesday, 60s to mid 70s on Wednesday...with temps trending back to around climo normal for the latter half of next week. Next chance of rain comes by the end of the period late next week in association with another weakening southern stream upper low traversing the southern tier of the country. For now, rain chances are re-introduced by late on Thu/Fri. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... VFR conditions through the 12Z TAF period. SSW winds average 10-15 kt...gusty to 20-25 kt early/mid this afternoon and BKN/OVC AC-CI. With weak sfc boundary pushing S to near SBY tonight...low prob for IFR (in ST and/or patchy fog) late tonight/early Sun. Otherwise...ISOLD- SCT SHRAS possible by late Sun into Mon...w/ only brief periods of reduced aviation conditions possible during times of precipitation. && .MARINE... High pressure is well offshore with a weak wedge left in the lee of the Appalachians. This feature should delay the onset of rain until mid to late morning as a cold front continues to advance on the area...effectively outrunning (or getting ahead of) the precipitation by late morning/early aftn. Weak troughing along the coast will cause the pressure gradient to tighten invof the cold front. Meanwhile, weak warm air advection will act to hamper the development of stronger winds. Overall, winds become s-sw 10-15kt (up to 20kt nrn coastal waters) by early aftn; peaking during the cold frontal passage. Seas build to 2-4ft; waves to 2ft. Little change to the airmass tonight behind the front as warmer air stays in place with strengthening high pressure building well north of the waters through Sun night. N winds tonight through Sun aob 15kt...becoming ne-e and diminishing to aob 10kt Sun night. Seas average 2-3ft; waves average 1-2ft. Main high pressure slides over Nrn New England/Canadian Maritimes on Mon. E-se aob 10kt. Weak wedging remains in place in the lee of the mts as a very strong low pressure system tracks into the Upper Great Lakes Mon and across Ontario/Quebec Mon night. The pressure gradient tightens up late Mon night into Tue aftn ahead of the front and s winds will increase to 15kt Bay and 15-20kt all coastal waters. Seas generally build to 3-4ft in this timeframe (up to 5ft possible coastal waters north of Parramore Island). Waves generally 2ft; occasionally up to 3ft. SCA flags are not anticipated. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...LKB NEAR TERM...ALB/LKB SHORT TERM...ALB LONG TERM...MAM AVIATION...ALB/LSA MARINE...BMD

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