Area Forecast Discussion
Issued by NWS Wakefield, VA

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747 FXUS61 KAKQ 180724 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 324 AM EDT Tue Jul 18 2017 .SYNOPSIS... A stalled frontal boundary across the area will continue the threat for scattered showers and thunderstorms through Tuesday. High pressure gradually builds toward the Mid Atlantic for the middle and later portion of the week...bringing a return to hot humid conditions. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 00Z MSAS has the frontal boundary disecting the fa NE-SW attm. Weak wave of low pressure and assctd convection moved east of mts and into the Piedmont past few hrs. Merging cells along this boundary led to rapid tstm growth but with little if any movement in any one cell. The result was tstms with heavy rain and some marginal hail. Some storms produced a quick 2 inches of rain in a very short time prompting the flood advsrys. Activity beginning to settle down now with loss of heating. High res data still shows sct convection through about 06Z with isltd pops across the sern zones. Data suggests a combination of a SC deck developing after midnight along with some patchy fog in areas away from the water. Lows in the upr 60s-lwr 70s. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... It looks like the upper trough will finally start to move east on Tuesday. Will need to maintain chance pops across SE VA/NE NC on Tuesday with the moisture continuing in advance of the trough. Will also go with isolated storms across the remainder of the area Tuesday afternoon given the upper trough axis is overhead. The trough axis passes over the area Tuesday night, with a drying trend expected on Wednesday (however a few sea breeze or bay breeze afternoon thunderstorms cannot be ruled out Wed). Big story starting Wednesday will be the return to the heat/humidity. Behind the upper trough, heights immediately build across the interior US and the middle Atlantic as the subtropical ridge extends into the south central US. As such, after a near normal temperature day on Tuesday, expect temperatures to rise to above normal with places in the low-mid 90s. There will likely be some mixing on Wednesday, so dewpoint values will most likely drop into the middle and upper 60s. So, heat index values should only rise into the upper 90s (maybe 100F in isolated spots) on Wednesday. The more significant heat index values will be Thu/Fri. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Bermuda High settles over the central Atlantic the rest of this week as very persistent troughing continues across the Eastern Seaboard. Mid Atlantic Region remains well ensconced in a warm sector throughout the long term forecast. Expect periods of unsettled weather with showers/storms developing each aftn/evening...especially invof lee trough axis which develops Wednesday and persists through at least Saturday. Otherwise, warm and muggy conditions continue with dewpoints in the upper 60s NW to around 75F SE. Meanwhile, high temps will be in the mid-upper 90s Thu/Fri/Sat (possibly pushing 100 degrees in cntrl VA on Friday) and low-mid 90s Sunday. Lows in the 70s each night. The combination of heat and humidity will support widespread heat indices in the 100-105 range with 105-109 possible SE for Thursday through Sunday. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... Wave of low pressure along a frontal boundary across the region has sparked off this evenings strong tstms, but they have stayed away from the airfields. Kept VCTS in at RIC for a few hrs based of current radar trends. Otw, chc not high enough through the night to include any pcpn. Data suggests a combination of a SC deck developing btwn 2-3K ft after 06Z along with some patchy MVFR BR across the Piedmont/lowr MD eastern shore. Another day of sct-bkn aftrn CU developing Tues with minimal chc of pcpn. OUTLOOK...High pressure builds over the SE Conus for the rest of the week with primarily dry conditions expected. && .MARINE... Trough sfc-aloft to gradually weaken through Wed...then hi pres rebuilds over the waters by the end of the week. Prevailing winds will remain SSW through the period...mainly aob 15 kt...though some increase in speeds late each day into the overnight hours. Seas 2-3ft. Waves 1-2ft. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...AJZ/MRD NEAR TERM...MPR/MRD SHORT TERM...MRD LONG TERM...BMD AVIATION...MPR MARINE...ALB/BMD

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