Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 251835 AFDAKQ Area Forecast Discussion National Weather Service WAKEFIELD VA 135 PM EST Sat Feb 25 2017 .SYNOPSIS... A cold front crosses the Mid Atlantic this afternoon and evening. High pressure and more seasonal conditions return Sunday and Monday. A warm front and associated surface low pressure track across the area Monday night into Tuesday. && .NEAR TERM /THROUGH TONIGHT/... Update...A severe thunderstorm watch has been issued for portions of Virginia and the Maryland Lower Eastern Shore until 800 PM this evening. Previous discussion... Sfc cold front located just west of the CWA as of 1230 PM this afternoon. Although convection in far SW VA waned this morning, a line of thunderstorms is redeveloping along the front due to daytime sfc heating. Current enhancement is terrain- induced, however it shouldn`t take much to keep this line going through the rest of today based on strong, unidirectional west winds through the atmospheric column. Thunderstorms will likely remain within organized line segments with strong wind gusts being the primary threat today. Some storms may quickly become severe with damaging winds and possibly a quick burst of large hail (1 inch or larger in diameter). Pwats have come up to around 1 inch, therefore the threat for very heavy rainfall and localized flooding is low. Pinpointing exactly where the strongest storms will occur will be a challenge, since the best dynamics lie NW of the Richmond Metro area to the MD Lower Eastern Shore and best differential heating/instability lies across sern areas of the forecast area. SPC has the entire local forecast area within a Slight Risk for severe storms today, which means that scattered severe thunderstorms are possible. Please stay aware of rapidly changing conditions and take shelter inside when threatening weather approaches/occurs. The sfc cold front and subsequent thunderstorms will quickly push eastward the rest of the afternoon into early evening... exiting the coast between 700-900 PM tonight. Gusty south winds ahead of the front/thunderstorms will quickly become W-NW behind the frontal passage and remain breezy through most of tonight... especially at the immediate coast where gusts should average 20-30 MPH. Dewpoints will fall faster than temperatures due to the well- mixed environment, thus making the ambient air feel cooler than the actual temperature. Either way, temps will drop into the low-mid 30s NW to upper 30s to around 40F SE by morning with skies becoming mostly clear by midnight. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... Sfc high pressure builds across the Southeast States Sunday, up along the SE VA coast Sunday night, and then moving well off the Mid Atlantic Coast on Monday. A warm front then lifts north into the region late Monday night into Tuesday. Conditions will be dry and more seasonal on Sunday with mostly sunny skies and breezy west winds during the afternoon (especially across the MD/VA Eastern Shore). Highs in the lower 50s inland (mid-upper 40s Nrn Neck and MD/VA Eastern Shore). Winds decouple Sunday night with light south winds but the area remains somewhat wedged in the cooler airmass. Lows generally in the lower 30s inland (mid- upper 30s immediate coast). Clouds increase late Sunday night into Monday as the sfc high moves offshore and shortwave moisture/energy begins streaming into the region from the southwest. Forecast remains dry on Monday with temperatures generally warming into the lower 60s (generally upper 50s far nrn counties and MD/VA Eastern Shore). The aforementioned warm front lifts north into the area late Monday night into Tuesday with continued partly to mostly cloudy skies and more substantial warm air advection taking place. Expect lows well above normal with readings in the upper 40s to around 50 NW to lower 50s SE. Highs will also be around 15 degrees above normal with readings in the lower 70s along/south of Interstate 64 and mid-upper 60s north of this line. Increasing chances for light rain showers Monday night into Tuesday should also be anticipated as isentropic lift (especially invof the warm front) will enhance precip chances in persistent SW flow aloft with shortwave energy/moisture streaming across the region. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A couple of opportunities for much-needed-rain are showing up in the medium range model guidance for next week. The first such opportunity is Monday night into Tuesday as a disturbance lifts NE across the region in the mid/upr levels. PoPs have been increased to ~60% for SE VA/NE NC, with 40-50% elsewhere (30-40% far NW) as 25/00z models remain in decent agreement. There is a brief reprieve Tuesday aftn/night before the next system is expected to impact the region during Wednesday. Subtle timing differences exist between the GFS and ECMWF with regards to timing of the onset of pcpn. However, agreement is good enough in the models at this point for solid chc pops (~40%). Drier weather looks to return late next week with high pressure attempting to rebound. Highs will remain unseasonably warm Tues/Wed from the mid 60s to the mid/upr 70s (warmest Wed). Trending cooler next Thursday/Friday with highs returning to the mid 50s to low 60s and lows in the 30s. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... A cold front with an associated broken line of showers and thunderstorms will cross the region later this afternoon allowing for a period of sub-VFR conditions at all sites. Showers/storms will enter the region mainly after 19Z and move east across the area, departing offshore after 00Z. Winds could gust in excess of 50 knots with the strongest storms. High pressure builds into the region behind the front Saturday night allowing for a return to VFR conditions. Gusty NW winds will be possible behind the front, especially near the coast and at SBY, tonight and into early Sunday. Outlook: High pressure slides offshore Sunday night into Monday, followed by weak low pressure Monday night and into Tuesday. This will bring a chance of rain to the region and the next chance for sub-VFR conditions. Another cold front will approach the region from the west on Wednesday. && .MARINE... Early this morning, low pressure was lifting NE well off the NC coast, while a cold front was pushing into the Appalachian mtns. The low will continue to move NE well off the East coast during today, while the cold front will cross the marine waters late this aftn thru this evening. A South wind will increase to 10 to 20 kt this aftn in advance of the front, but should still remain sub-SCA, although locally stronger gusts are possible with tstms this aftn into early this evening. Seas are currently running 3-5 ft, and will increase to 4-6 ft all ocean zones later today into tonight with the frontal passage. Waves in the Ches Bay will increase to 2-4 ft. The cold front will move off the coast this evening/early tonight followed by modest CAA and strong pressure rises. NW winds will average 15-25 kt with gusts to 30 kt and 4-6 ft seas/3-4 ft waves into Sun morning. SCA flags are in effect fm this evening thru late tonight for the Ches Bay, Sound and Rivers. SCA flags are in effect for the coastal waters thru Sun morning. The wind diminishes Sun aftn as high pressure builds into the region. High pressure quickly pushes offshore Sun night into Mon with the wind becoming S. && .CLIMATE... Feb 2017 is shaping up to rank among the warmest on record given continued warmth over the next week. Daily record highs are listed below for today and Sat, with the top 3 warmest February`s on record listed below that. Expecting RIC, ORF to be the 2nd warmest and ECG to be at least into the top 3 warmest. SBY looks on track to be 4th or 5th warmest. Daily Record Highs for Saturday 2/25: 2/25 ---------- RIC 83 in 1930 ORF 81 in 1930 SBY 80 in 1930 ECG 77 in 1985 Warmest February`s on record (average temps): * RIC: (most likely finish for 2017: 2nd warmest) 1) 49.9 (1890) 2) 48.5 (1976) 3) 48.1 (1884) * ORF: (most likely finish for 2017: 2nd warmest) 1) 52.4 (1890) 2) 50.5 (1909) 3) 50.1 (1990) * SBY: (most likely finish for 2017: 4th warmest) 1) 46.1 (1976) 2) 45.8 (1984) 3) 45.7 (1925) * ECG: (most likely finish for 2017: 3rd warmest) 1) 52.1 (1990) 2) 51.8 (1939) 3) 50.3 (1976) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 4 AM EST Sunday for ANZ635>638. Small Craft Advisory until 6 AM EST Sunday for ANZ630>634. Small Craft Advisory until noon EST Sunday for ANZ650-652-654- 656-658. && $$ SYNOPSIS...BMD NEAR TERM...BMD SHORT TERM...BMD LONG TERM...AJZ/JDM AVIATION...AJB MARINE...TMG CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.