Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 170054 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 854 PM EDT Sun Jul 16 2017 .SYNOPSIS... A weak boundary lingers across northern North Carolina tonight before dissipating on Monday. High pressure off the Atlantic coast will re-establish itself for the mid week period, bringing a return to hot and humid conditions. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Name the trigger and we got it across the region this evening. Stalled frontal boundary along the border, trof of low pressure over the piedmont, weak s/w energy across nern NC along with numerous sea / bay/ river breeze features. Main threat was heavy rainers. Activity winding down attm, but went ahead and expanded the slght chc pops farther north to cover the lone stationary cell in King William county. Otw, high res models show a several hour lull in the pcpn across the sern portions of the fa after midnight then increase activity a bit toward daybreak. Data also indicates some patchy fog developing across the piedmont and areas that did see rain this evening but just not sure how much or widespread it will be as drier air works in aloft. Lows in the upr 60s to lwr 70s.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Similar day weatherwise expected tomorrow. Upper trough axis digs from the Ohio Valley across the interior northeast early Monday. This will shunt weak surface front over the Great Lakes toward the local area. Ahead of the front, a lee-side pre-frontal trough develops over the Piedmont, w/any convection should be diurnally driven and generally confined to the Blue Ridge to the west. Meanwhile, old boundary to the south will weaken further through the day, with iso-sct convection focused along the far SE portion of the CWA down into E NC, initiated primarily by seabreeze interactions to the E. A low end chance PoP (30-40%) has been maintained over far SE VA into NC. Otherwise, no real trigger mechanism in between the two previously referenced features outside of any convective outflows, so will hold PoPs at slight chc (20%) for most of the local area from central VA to the Ern Shore. Highs again in the upper 80s to around 90 after morning lows of 70-75F. Previously referenced front washes out as it drops across the area Monday night into Tuesday and washes out. Meanwhile, a sprawling upper level ridge will begin to build east from the Plains on Wednesday, nudging the upper trough toward the SE coast. Any convection Tue/Wed should be primarily diurnally driven with PoPs of 20-30% (highest along the coast). Due to lack of deep layer shear and weak steering flow, locally heavy rainfall and lightning remain the primary hazards each day. High temperatures reach the upper 80s to low 90s Tuesday after morning lows in the 70s. Slightly warmer and modestly more humid Wednesday with highs in the lower to middle 90s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Bermuda High settles over the central Atlantic the rest of this week as very persistent troughing continues across the Northeast. Mid Atlantic Region now anticipated to remain within 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; position of trough varies each day. Otherwise, warm and muggy conditions continue with highs generally in the low-mid 90s, lows in the 70s, and dewpoints in the mid 60s NW to around 75F SE. This should support widespread heat indices in the 100-105 range with 105-108 possible SE for Thu/Fri. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Weak low pressure riding ENE along the stalled frontal boundary along with merging outflow / seabreeze boundaries was the trigger for this evenings convection. Said convection winding down with only ECG having any thunder. Based on the radar trends of this activity weakening, went ahead and kept TSTM at ECG for the next 1-2 hours expecting the activity to dissipate before midnight. Otherwise, guidance hinting at some patchy MVFR fog late tonight over inland areas. Added some BR at ECG as well given how much rain fell this evening. Another round of diurnal convection expected Mon but chcs to low to include in the forecast attm. Went with a BKB CU deck for now. OUTLOOK...Deep layer SW flow returns mid week as the Atlantic ridge establishes itself once again. Pcpn chcs aob 20%. && .MARINE... A stationary frontal boundary is located across nrn NC late this aftn. Isolated to scattered thunderstorms have developed invof this boundary and will persist into this evening. Storms are slow-moving and will be highly proficient at producing very heavy rainfall and isolated gusty winds. Showers/storms gradually shift towards the coast overnight as the frontal boundary washes out/dissipates into Monday. Another round of isolated to scattered storms will be possible (mainly over srn waters) in the aftn/evening. Otherwise, the Bermuda High settles over the cntrl Atlantic as very persistent troughing continues across the Northeast through the rest of this week. Expect periods of unsettled weather and generally south winds aob 15kt through the end of the forecast period (Thu night). Seas 2-3ft. Waves 1-2ft. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MAM NEAR TERM...MPR SHORT TERM...AJZ/MAM LONG TERM...BMD AVIATION...MPR MARINE...BMD

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