Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 221025 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 625 AM EDT Tue May 22 2018 .SYNOPSIS... A weak frontal boundary will lift back north as a warm front early this morning and will push north of the area this afternoon. A more pronounced cold front will cross the region on Wednesday, followed by a period of dry weather Thursday and Friday under the influence of high pressure. && .NEAR TERM /THROUGH TONIGHT/... As of 355 AM EDT Tuesday... Weak frontal boundary beginning to drift NE early this morning with widespread low clouds and some areas of fog (though vsbys are genly at or above 1SM). Scattered showers are affecting mainly W sections of the region, but will shift a bit to the east through the morning. The front will continue to move northward later this morning and aftn but will be somewhat slow to clear N/NE sections of the CWA. Will have 20-40% Pops through mid/late morning then a few hrs with 20% or lower PoPs before a lee side trough develops during the afternoon. This, combined with a weak upper wave moving through the W-NW flow aloft will allow for a line of storms to develop across northern VA and perhaps impact the far northern part of the forecast area late this afternoon. The winds aloft are in the 35-40kt range Tuesday afternoon, which may be just enough for some strong wind gusts with any thunderstorm. SPC has placed northern VA, including the nrn 1/2 of the CWA into a marginal risk for severe thunderstorms. Think greatest chance for storms will be late, from about 4pm through 10pm or so. Highs today mainly from the low-mid 80s except cooler on the eastern shore (in the 70s). This line of showers/storms will move through the forecast area this evening and will likely diminish well after sunset due to loss of daytime heating. Lows tonight warm/humid in the mid/upper 60s to around 70 F. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 355 AM EDT Tuesday... On Wed, the sfc front is progged to be pushing through the CWA by 12Z, but instability will not be that great at that time. Will have highest PoPe Wed morning over NE NC/far southern VA, where deepest moisture resides. Best chances for showers/storms will be Wed afternoon due to height falls aloft and decreasing stability along the frontal zone. There is a marginal risk for severe storms on Wednesday across southern 2/3 of the area, but the best chance for any severe weather will likely be across the far southern tier where the best instability will occur. Highs mainly in the 80s. Models in good agreement with strong push of NW flow aloft as a deep upper trough slides off into Atlantic Canada with upper ridging amplifying across the upper MS Valley and into central Canada. This will allow for a significant drop in moisture for Thu even though aftn high temperatures will remain warm (in the upper 70s/around 80 F at the coast and lower-mid 80s inland). Dew pts are likely to drop into the low-mid 50s over much of the area dew points as high pressure builds across the region from the NW. Skies will avg mostly sunny. Mostly clear w/ diminishing winds Thu night should allow for low temperatures down into the upper 50s to lower 60s. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 320 PM EDT Monday... A strong surface ridge and northwest flow aloft with the upper ridge axis to the west over the Mississippi Valley will provide dry weather with moderate temperatures for the beginning of the extended forecast. Expect highs in the low to mid 80s Friday and the mid to upper 80s on Saturday. Overnight lows in the mid to upper 60s Friday night. But the upper ridge will erode through the holiday weekend with a gradual increase in moisture as it appears that another area of low pressure will form in the northeastern Gulf of Mexico by Sunday and push more tropical moisture northward into the region. This could allow for more showers and tropical downpours for Sunday and again on Monday. The big model difference in the models is the handling of a backdoor cold front between the 12z GFS and ECMWF with the GFS pushing the front south through the area and the ECMWF keeping the boundary well north of the area. In either case, the chance for showers and some possibly heavy rainfall exist for the second half of the Holiday weekend. If the GFS is right with the front Monday could be a damp cool rainy day while the ECMWF would lead to more periodic showers with some breaks. At this time of year, seems more likely the for the front to hang north of the area. So have kept the temperatures up more in the low to mid 80s for Sunday and Monday. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... As of 145 AM EDT Tuesday... Weak frontal boundary slowly lifting NNE early this morning into NE NC and south central VA. Showers have genly diminished as they move into the local area, but some spotty showers may begin to affect KRIC/KORF/KPHF/KECG from about 10-15Z this morning. Flight restrictions are expected to drop down to IFR/LIFR for cigs and MVFR/IFR for vsbys from 08-14Z (the exception being KSBY where VFR prevails through 12Z then some MVFR possible from mainly 12-18Z). Added VCSH to all sites but SBY. Continued IFR- MVFR CIGS Tue morning...then local area enters warm sector w/ SCT- BKN CU and possible SHRAS- tstms in the late afternoon/evening (best chance for tstms will be after 20Z at KRIC/KSBY with a lower chance elsewhere). Mainly afternoon/eve SHRAS/tstms are possible Wed as a cold front crosses the local area. Sfc high pressure looks to build in from the N by Thu and Fri bringing mainly VFR conditions during the end of the week. && .MARINE... As of 355 AM EDT Tuesday... Latest obs reflect a light E-SE flow across the waters this morning. The latest surface analysis reveals weak frontal boundary oriented just s/sw of the waters early this morning. Expect surface ridge to the south across the Carolinas will nudge front back north across the waters later today, slowly lifting back north across the local area from late morning through the afternoon, with surface winds to veer around to the S-SW behind the boundary. Pressure gradient tightens slightly, but remains weak and therefore expect winds to remain no more than 10-15 kt. Seas remain ~2 to 3 feet on SE swell of ~6-8 seconds w/waves 1 to 2 feet. Models continue to develop some more scattered convection along the returning front across lower Bay and central/southern waters this afternoon, gradually diminishing into the evening. Additional showers and storms are possible over northern waters by late afternoon into the evening. S-SW flow persists Tuesday night. Winds do nudge upward slightly over southern waters, as pressure gradient tightens slightly ahead of next front. However, conditions should remain predominately sub- SCA (~15kt lower Bay and southern coastal waters). Weak surface cold front crosses the region on Wednesday. However, given the typical late-spring pattern in place, cool air push behind the front is minimal, and little more than a post-frontal wind shift to the W-NW is expected late Wednesday into Thursday morning. High pressure builds into the area Thursday through Friday, leading to developing lift N-NE flow and generally tranquil marine conditions into the start of the holiday weekend. && .HYDROLOGY...
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As of 625 AM EDT Tuesday... Flood warning continues for the Appomattox River basin. Mattoax is now forecast to reach moderate flooding by late tonight/early Wednesday morning. Warning has been dropped at Stony Creek, with river falling below flood stage earlier this morning. Additional flood warnings continue for the Chickahominy, Mattaponi rivers, as well as the Pocomoke River in MD. (allowed South Anna/Pamunkey river to expire). See FLWAKQ or FLSAKQ for more details.
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&& .CLIMATE... As of 145 AM EDT Tuesday... * RIC monthly rainfall total through 5/21 remains at 8.84" (already ranks as 5th wettest May on record). (precipitation records date back to 1880) * SBY monthly rainfall total through 5/21 remains at 8.52" (already ranks as 3rd wettest May on record). (precipitation records date back to 1906) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB/MRD LONG TERM...ESS AVIATION...LKB MARINE...MAM HYDROLOGY... CLIMATE...

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