Area Forecast Discussion
Issued by NWS Wakefield, VA

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152 FXUS61 KAKQ 250306 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 1106 PM EDT Wed May 24 2017 .SYNOPSIS... Unsettled conditions return this evening through Thursday as an upper level trough approaches from the west. Conditions improve on Friday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Latest GOES water vapor imagery centers deep/anomalous low pressure over the lower Ohio River Valley, with a plume of moisture spreading northward along the Southeast coast. Precipitable waters, per latest GPS precipitable waters, are progged around 1.6 to 1.8 inches (150%+ of normal). At the surface, a warm front remains just south of the local area with an area of low pressure developing along the lee side of the Appalachians. The combination of strong dynamics, a moist air mass, and forcing along the warm front has resulted in widespread showers across the region this evening. The brunt of the showers has pushed north of Interstate 64 late this evening. However, more showers are expected through the overnight period as a potent shortwave ejects northeast from the Deep South into the Southeast. The warm front lifts northward along the coast as a meso-low develops over the forecast area ahead of the height falls. A trailing cold front crosses the area late tonight. These features will be the focus for additional showers through the overnight period. Categorical POPs continue. A line of more organized showers is stretching along the cold front from near Roanoke southward toward the Florida/Georgia line. As the warm front lifts northward after midnight, RAP/HRRR guidance indicates theta-e advection and warming temperatures/dewpoints will result in marginal instability across the southeast local area. In addition to 30-40 knots of shear, the approaching line of showers could be enhanced across the southeast forecast area. Wind gusts of 30-40 mph and small hail cannot be ruled out along the line. Drying conditions expected behind the front late tonight, before additional chances for showers/thunderstorms Thursday. Temperatures will remain generally in the low to mid 60`s through the overnight, even warming a few degrees across the southeast. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... Upper low begins to lift NE across the mountains Thursday. A strong shortwave trough will lift across the mid-Atlantic during the afternoon/early evening. Once again PoPs increase...to ~60-70% from the Piedmont to central VA to the MD Ern Shore, with 40-50% far SE. 500mb flow of 45-55 kt is expected along with modest instability. Therefore...a few stronger to marginally severe storms are possible. The main threat would be wind and hail as low-level shear is minimal but a decent cold pool aloft will exist. Additional QPF Thu aftn/evening should average up to ~0.25" with locally higher amounts possible. Highs Thu in the m70s W of I 95 to the l80s across eastern portions of the FA. The upper low continues to lift NE across PA/NY/New England late Thu night into Fri. Drier conditions finally arrive as deep layered WNW flow develops over the region. Some lingering mid-level energy could result in SCT-BKN CU mid/afternoon Fri. Otherwise...drier and breezy with highs in the u70s to l80s, after morning lows in the m50s W to l60s at the coast. Weak ridge aloft nudges into the region from the WSW Fri night into Sat. Differing potential/timing in arrival of weak S/W tracking into the FA by Sat afternoon. Combination of daytime heating and that S/W in WNW flow aloft may result in at least SCT convective development. Otherwise...partly cloudy Fri night-Sat morning...then becoming mostly cloudy Sat afternoon. Lows from the u50s NW to the l60s SE. Highs Sat from the m70s- around 80F on the eastern shore to the m80s inland. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Long term period starts off Sat night into Sun with a warm front in the vicinity and plenty of energy passing through the WNW flow aloft. This will lead to a chance of shras/tstms everywhere, with low temps in the 60s Sat night and high temps in the low/mid 80s Sun. Continued chance of rain into Mon with a weak cold front passing through the area. Highs again in the low/mid 80s. Drier weather into Tue and Wed behind the front, but still cannot rule out the chance of a shra or tstm with continued cyclonic flow aloft. High temps in the upr 70s to mid 80s both days. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... MVFR/IFR conditions across the CWA and TAF sites with east flow and lots of moisture over the region. A low pressure system over the TN Valley continues to bring lots of moisture and precipitation over the Mid Atlantic region. A warm front just south of the VA border is helping to induce some convection as the moisture moves north. The rain and thunderstorms will prevail over the area through the night and into Thu morning. Widespread IFR ceilings are expected during the overnight. The low will lift into the OH Valley by Thu afternoon and the precip will move north and east of the region. Some scattered showers will again be possible Fri afternoon but MVFR/VFR conditions across the region. Drier/VFR wx returns by Fri as weak high pressure builds over the region. Unsettled conditions return for the weekend when another frontal boundary affects the Mid Atlantic States. && .MARINE... Latest sfc analysis shows a low pres system centered over the OH Valley with a warm front stretching across the VA-NC border. The front slides north tonight, and with an increasing pres gradient, expect SCA winds to commence over the Bay late. Also expect seas to build up to 5 ft out 20 nm late. For Thu, a weak cold front crosses the area, and SW flow may come close to SCA thresholds over the Bay. Decided to just continue the headlines there through Thu night since winds may ramp up again then. Also, seas may continue to meander around 5 ft out 20 nm. Will end headlines at the end of the third period attm. Lwr James and Currituck Sound may potentially need to be added to the SCA Thu/Thu night as well. Weak high pres then builds in for Fri leading to improving marine conditions. Sub-sca conditions expected to continue into the weekend. && .TIDES/COASTAL FLOODING... A period of onshore flow and high astro tides (moving toward a new moon) will result in elevated water levels through Friday. Issued several coastal flood advisories and statements for tonight`s high tide cycle...refer to CFWAKQ for more details. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Coastal Flood Advisory until 6 AM EDT Thursday for MDZ021>023. NC...None. VA...Coastal Flood Advisory until 3 AM EDT Thursday for VAZ089-090- 093. MARINE...Small Craft Advisory until 7 AM EDT Friday for ANZ630>632-634- 650-652-654-656-658. && $$ SYNOPSIS...JDM NEAR TERM...SAM SHORT TERM...ALB/JDM LONG TERM...MAS AVIATION...ALB/JEF MARINE...MAS TIDES/COASTAL FLOODING...

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