Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 201028 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 628 AM EDT Sat Jul 20 2019 .SYNOPSIS... High pressure remains off the Southeast coast through Monday. A cold front crosses the area Monday night, ending the current heat wave by Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 245 AM EDT Saturday... Heatwave rolls on today. Strong ridge aloft remains in control INVOF the FA limiting any significant clouds and putting a cap on convective potential. The challenging part of the forecast is the dew point which models using have difficult time resolving. Mixing will remain limited again today...though some guidance does suggest that dew points...esp W of I 95 do lower a bit this afternoon around peak heating which would limit HI to blo 110 degs F. Otw...expecting HI to top out between 110-115 deg F as high temperatures reach 95-100F. Keeping Excessive Heat Warning for all areas today (ongoing over the SE...starting at 15Z/20 elsewhere). One or two stray tstms may pop later today...some near term hi res guidance does suggest the potential for that N and NW of RIC and along the SSW rim of the FA after 21Z/20. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... As of 305 AM EDT Saturday... Ridge aloft remains strong enough through Sun to keep the heat going and limit any convective potential. After another very warm/humid night tonight (HI likely doesn`t fall blo 85F in many urban areas)...very hot/humid conditions expected again Sun. There is the hint of a weak trough just W of the FA (over the higher terrain) Sun afternoon/evening which may be enough for ISOLD-SCT tstms there. Elsewhere...PoPs to remain blo 15%. Heat warning headline will remain up tonight through Sun evening all areas. Still very warm/humid Sun night. PoPs mainly aob 15%. Ridge aloft breaks down Mon and a cold front approaches from the NW. Another hot day...though the heat will likely be trimmed over NW portions. Highs NW in the l90s...while another day of m-u90s likely central and E. A heat advisory will likely be needed E and SE portions though there will likely a bit of SW (to 15 mph) which may help mix out/lower dew points at least a little bit. PoPs increase to 30-50% NW and 15-25% SE by late Mon afternoon/evening...though some of the model guidance is now about 6 hours slower w/ the arrival of the cold front`s influence. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 330 PM EDT Friday... Guidance continues to suggest a fairly abrupt cool down by Tuesday as a long wave trough sets up across the eastern half of the country. At the surface, low pressure is progged to track from PA to the Canadian Maritimes. Guidance has trended slightly slower w/ the passage of the associated cold is now forecast to approach the region Monday night before slowly crossing the area (from NW-SE) on Tue. Tstm chances increase from NW to SE Mon night- Tue as the front slowly crosses the region. The best chc of tstms Mon night will be across the nrn half of the CWA. As the front approaches SE VA/NE NC Tue aftn, expect re-development of showers/tstms (as pcpn chances diminish across northern/western zones). Guidance is in very good agreement with respect to numerous shower/tstm coverage Tue aftn-evening across the SE. Have likely PoPs across the north Mon night with chc PoPs across the south. Have gone with PoPs of ~70% across the SE Tue aftn-evening. The best chc for stronger storms looks to be across SE VA/NE NC Tue aftn where the FROPA coincides w/ peak heating. The front finally moves just SE of the CWA on Tue before slowly pushing well S of the area by Thursday. Deep-layer moisture will be slow to exit coastal SE VA/NE NC under moist SSW flow aloft. Therefore, will maintain chc PoPs through late Wed across far SE zones. Drier by late next week as high pressure tries to build in from the north. Still cannot rule out an isolated aftn-evening shower/tstm (especially S) through Fri. Highs generally dropping back to the low-mid 80s for Tue and Wed, then mid-upper 80s Thu-Fri with more sunshine. Morning lows will mainly be in the upper 60s-mid 70s on Tue before dropping into the 60s in most areas from Wed-Fri (with forecast lows in the low 70s along the immediate coast of SE VA/NE NC). && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... As of 625 AM EDT Saturday... VFR conditions expected through the 12Z TAF forecast period. FEW-SCT CU again midday/afternoon w/ mainly SSW winds blo 10 kt. An ISOLD tstm can`t be ruled out in the aftn/early evening but bulk of any convection expected to stay S and W of the local area. Upper level ridge slowly breaks down late Sun- Mon...allowing for a bit better coverage of late day/eve convection (by Mon afternoon - as cold front approaches and drops across the FA). High PROB for SHRAs/tstms Mon night into Tue as that front is slow to push to the E and S. && .MARINE... As of 350 AM EDT Saturday... No headlines in the short term today thru Sun night. Strong high pressure at the surface and aloft over the SW Atlc was resulting in continued SW winds 5-15 kt over the waters early this morning. Waves were 1-2 ft in the Bay, with seas 2-3 ft. SSW winds mainly 5-15 kt will continue over the waters today into Mon night, as high pressure remains anchored off the SE coast. Large scale ridging will break down late Mon/Mon night, as a surface trough precedes an upper level disturbance across the Great Lakes. SW winds will increase as the pressure gradient begins to tighten Mon aftn into Mon night, generally 10-20 kt over the waters, highest in the srn Ches Bay, Currituck Snd and coastal waters. Waves will build to around 2 ft, while seas will build to 3-4 ft, possibly to 4-5 ft in the nrn three coastal zns. A cold front will then drop across the waters Tue into Tue evening, with winds shifting to the NW or N around 10 kt or less behind the boundary into Wed morning. A period of showers and storms (some of which may be quite strong) will precede this front. && .CLIMATE... Best chance for breaking records with this heatwave will be record high mins as the airmass is very humid. Record highs and record high mins are listed below: * Richmond: Record High Record High Min * Sat (7/20): 103/1930 78/2013 * Sun (7/21): 104/1930 77/1930 * Mon (7/22): 103/1952 79/2011 * Norfolk: Record High Record High Min * Sat (7/20): 102/1942 79/1977 * Sun (7/21): 101/1926 80/1983 * Mon (7/22): 102/2011 82/2011 * Salisbury: Record High Record High Min * Sat (7/20): 104/1930 83/2013 * Sun (7/21): 106/1930 77/2017 * Mon (7/22): 104/1930 80/2011 * Eliz City: Record High Record High Min * Sat (7/20) 104/1942 78/2012 * Sun (7/21) 102/1987 79/1983 * Mon (7/22) 104/1952 79/2011 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Excessive Heat Warning from 11 AM this morning to 11 PM EDT Sunday for MDZ021>025. NC...Excessive Heat Warning until 11 PM EDT Sunday for NCZ012>017- 030>032-102. VA...Excessive Heat Warning from 11 AM this morning to 11 PM EDT Sunday for VAZ048-060>062-064>069-075>080-099-100-509>517- 519-521-522. Excessive Heat Warning until 11 PM EDT Sunday for VAZ081>090- 092-093-095>098-518-520-523>525. MARINE...None. && $$ SYNOPSIS...MPR NEAR TERM...ALB SHORT TERM...ALB LONG TERM...ERI AVIATION...ALB MARINE...TMG/RHR CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.