Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 250100 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 900 PM EDT SUN JUL 24 2016 .SYNOPSIS... An upper level ridge prevails over the Mid-Atlantic region through Tuesday. A weak cold front approaches from the north Tuesday and drops into the region Tuesday night into Wednesday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Early evening satellite imagery shows a strong upper ridge centered over the Southeast US. At the surface, high pressure remains centered from the Southeast to the wrn Atlantic, with a lee-side trough embedded to the east of the Blue Ridge. Localized convergence triggered a few isolated showers/tstms over the Middle Peninsula late this aftn. As with activity yesterday, loss of heating and minimal forcing has allowed this activity to quickly dissipate. Watching some sct showers back into the Blue Ridge associated with a weak shortwave slipping across the Mason-Dixon line. Possible that a brief shower could occur across far NW tier of counties over the next hour or two, but HRRR/CAMs do not favor any significant convective development surviving into the area, instead remaining just to our NNW. As such, will stick with a silent pop overnight. Very warm and humid overnight, as temperatures slowly fall into the low to mid 80s by midnight. Overnight/early morning lows falling only into the mid/upper 70s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... The broad upper ridge dampens over the Ohio Valley Monday but remains firmly entrenched over the wrn Atlantic. 1000- 500mb thickness values rise to around 5820m over the Piedmont and 850mb temperatures average around 22-23C across the region. This should easily support highs in the upper 90s to near 100 across the area with even low 90s at the immediate coast. Dewpoints again should remain in the low/mid 70s through peak heating across central/se VA and ne NC. The boundary that brought some reprieve in dewpoints today from the Nrn Neck to the Lower MD Ern Shore will retreat to the ne allowing for dewpoints in the low/mid 70s by Monday. This result in widespread heat indices of 105 to 109. The only exception is the MD beaches with heat indices of 100 to 104. Given this a heat advisory has been issued for the entire area Monday with the exception of the MD beaches. Urban locations of Hampton Roads could push warning criteria Monday afternoon (110+). Confidence is not high enough to go with a warning at this time and subsequent shifts can re-evaluate. Forecast soundings continue to depict a strong cap around 800mb Monday, so no convection is expected during the day Monday. There is a minimal chc (~20%) of a stray tstm drifting off the higher terrain and reaching the far nrn tier counties Monday evening. The upper ridge begins to slowly break down Monday night into Tuesday. Remaining warm and humid Monday night with lows in the mid/upper 70s. Continued hot Tuesday as 1000-500mb thickness values only drop to around 5780-5800m and 850mb temperatures drop only to 20-21C. This will support highs in the mid 90s. Dewpoints remain in the low/mid 70s with heat indices again aoa 105 with heat advisory criteria likely reached again for much of the area. The ridge breaks down enough late Tuesday afternoon into Tuesday evening to allow a weak front to drop into the area and shortwave energy to cross the mountains. This will result in a 30-40% chc of showers/tstms mainly after 19z west, and after 22z farther east. Still warm and humid Tuesday night with lows in the mid/upper 70s. Westerly flow aloft will allow for the boundary to stall over the region Wednesday. 24/12z data suggests the highest chc (30-40%) will be from central/s- central VA to se VA and ne NC. Highs reach the low 90s under a partly sunny sky. Dewpoints will be highest across se VA/ne NC with heat indices of 100 to 104 possible. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Stacked high pressure over the Southeast Coast allows zonal/westerly flow aloft to settle across the region through the rest of the week. A series of weather disturbances will pass across the region as a thermal boundary/lee trough sets up over the area. This will provide a focus for thunderstorm development and keep a chance for storms in the forecast each aftn/evening. Areal coverage fluctuates with each passing model run and will therefore maintain more broadbrushed POP grids. Pwats around 2.00-2.25 inches and dewpoints in the low-mid 70s will result in muggy conditions with ample moisture present across the area. Factor in weak steering flow aloft and the anticipated impacts from any thunderstorms will be locally heavy rainfall and strong gusty winds. Combine the humidity with temperatures remaining in the lower 90s, and heat indices will continue to run around 100-104 degrees with a few pockets in far SE VA/NE NC reaching 105-106 degrees for an hour or two each aftn. Lows generally in the low-mid 70s inland and mid-upper 70s beaches. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... High pressure over the Northeast States helped to shift winds to an easterly direction late Sunday at ORF and SBY. This high will quickly weaken as low pressure moves across the Great Lakes. High pressure off the SE U.S. coast will once again become the dominant weather feature by Monday morning. No visibility restrictions are expected overnight. A dry day is indicated for Monday with SW winds of around 10 knots. A few higher gusts are possible. OUTLOOK...A cold front drops into the area late Tuesday and then stalls over northern portions of the Mid Atlantic States. A daily chance for afternoon and evening thunderstorms can be expected Tuesday through Friday. && .MARINE... Generally quiet/benign conditions expected the rest of this week. Winds generally s-sw aob 15kt during this time as high pressure remains steadfast over the Southeast Coast. Meanwhile, westerly flow aloft will allow a series of weather disturbances to cross the region and keep a chance for thunderstorms in the forecast each aftn/evening. Seas average 2-3ft...waves average 1-2ft. There may be a surge in sw winds to 15kt srn Ches Bay/Sound and 15-20kt coastal waters Monday night ahead of the approaching weather, however SCA flags are not anticipated at the moment. Seas may briefly build to 3-4ft nrn coastal waters...waves to 2-3ft srn Bay Monday night. && .CLIMATE... While its certainly going to be hot thru Tue, climatologically this is the hottest time of the year with several heat waves having occurred in the past that have been more intense than what we will experience. No records were set Sunday. Record highs are not expected to be set Mon/Tue. * RECORD HIGHS: For Sunday (7/24) * RIC:105 (2010) (Actual high 96) * ORF: 105 (2010) (Actual high 100) * SBY: 101 (2010) (Actual high 94) * ECG: 97 (2012) (Actual high 95) Records Mon (7/25) Tue (7/26) * RIC: 105 (2010) 100 (1940) * ORF: 105 (2010) 100 (1940) * SBY: 100 (2010) 102 (1940) * ECG: 97 (1949) 97 (1949) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Heat Advisory from noon to 8 PM EDT Monday for MDZ021>024. NC...Heat Advisory from noon to 8 PM EDT Monday for NCZ012>017- 030>032-102. VA...Heat Advisory from noon to 8 PM EDT Monday for VAZ048-060>062- 064>069-075>090-092-093-095>100-509>525. MARINE...None. && $$ SYNOPSIS...AJZ/MPR NEAR TERM...AJZ/MAM SHORT TERM...AJZ/MPR LONG TERM...BMD AVIATION...LSA MARINE...BMD CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.