Area Forecast Discussion
Issued by NWS Wakefield, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KAKQ 160624 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 124 AM EST Tue Jan 16 2018 .SYNOPSIS... Arctic high pressure will extend south into the region tonight. A cold front crosses the area Wednesday morning with low pressure moving northeast along the coast Wednesday afternoon and night. A second surge of arctic air pushes across the area Wednesday night and Thursday before temperatures moderate into next weekend. && .NEAR TERM /THROUGH TODAY/... Latest wx analysis features strong sfc high pressure lifting NE across Atlantic Canada, with the surface ridge still down into interior portions of VA/NC. A sfc trough is still situated just off the NC/VA coast and continues to keep low clouds in place over eastern sections of the CWA this evening. Earlier snow showers across the eastern shore have ended, with the main challenge for the overnight forecast being with clouds and potential for fog. In general, the model output showing widespread vsbys less than 1Sm over eastern and SE VA appears way overdone given all of the cloud cover that will be slow to diminish (if at all). Have added some 3 to 5 SM vsbys E of I-95 later tonight but unless all of the low clouds scatter out, dense fog looks unlikely even though winds will be rather light. As for overnight lows, it will be much colder west of I-95 where dew pts are significantly lower and skies stay mostly clear for much of the night, expect lows 15-20 F over much of the Piedmont. Lows will avg 20-25 F across the I-95 corridor and a few counties on east, with 25-30 F more likely near the coast in clouds and a light NE flow. Another weak low progged to lift north just off the coast Tue with a cold front approaching from the west. The local area will be in btwn these features as weak high drifts toward the Carolina coast. Although weak, the return flow results in a short lived warm-up across the region as temps rise into the low- mid 40s. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... Closed upper low over western Great lakes will be the main weather maker in the short term period. Emerging model agreement with the 12z suite of models that the system will slide east, as a progressive, positively tilted trough by Wednesday. This system will eventually shunt a stalled frontal boundary east, ramping up snow chances Late Tue night and Wed as better lift/dynamics arrive into later Tue night. Have trended toward blended 12z ECMWF/NAM solution with the fcst package. This is a slightly slower solution, but maintains the open wave aloft. In turn, this allows the development of the SFC low slightly closer to the coast, albeit still offshore. It also allows a stronger piece of the shortwave to push across the local area into Wednesday aftn. Forecast confidence has improved enough to nudge much of the CWA up into likely POP, with the exception for the far NE zones. Overall, timing has slowed slightly, but still on track for late Tue night across the piedmont, towards sunrise Wed Metro RIC, and Wed morning Tidewater. Likely pops then continue Wed across the Piedmont as the upr lvl moisture tracks SE. Will need to watch for sharpening axis of f-gen/OPRH depicted by the high-res NAM...as it may portend to a period of moderate snow even into Hampton Roads Wed aftn. Have accordingly bumped snow accums up there slightly. Highs 30-35. Pcpn exits off the coast Wed evening with decreasing clouds after midnite. Cold as yet another shot of arctic air overspreads the area so would think any snow or water from the storm freezes solid. Lows 15-20 except lwr 20s sern coastal zones. QPF has nudged up slightly ~.10 east of the I95 corridor, .10 to .25 i-95 corridor and west. Expect varying SLR`s across the fa as well ranging from arnd 10:1 across the se to as much as 15:1 over the Piedmont. This translates mainly to an advsry level event with amts ranging from inch or less east of I95, 1-2 inches along the I95 corridor, 2 to 4 inches across the Piedmont (given the higher SLRs). Will hold off on headlines for one more cycle, as it appears models are starting to click into agreement. Advisories will likely be needed for a good part of the CWA given timing. Behind the system, departing upper trough will usher in another quick burst of arctic air for Wed night into Thursday. Lows Wednesday night back down into the teens to around 20. Could see some high single digits possible inland Wed night. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Pattern change looks to occur during the medium range period with a significant warmup expected through the upcoming weekend/early next week. It will still be on the cold side Thu night with sfc high pressure centered across the deep south, and one last upper trough moving SE through the Great Lakes and off the New England coast Fri morning. Mostly clear skies will prevail over the local area with lows mainly in the 20s though depending on remaining snow cover, some upper teens will be possible across interior southern VA. Latest GFS/ECMWF/CMC depict the upper trough moving well off the New England coast Fri with a broad upper level ridge building over the eastern CONUS Fri aftn through the weekend. Expect continued dry conditions with warming temperatures, highs in the upper 40s/lower 50s Fri, rising well into the 50s (possibly near 60F) Sat, and into the 60s (except at the immediate coast/eastern shore) for Sun. Lows Fri night/Sat am in the mid 20s to mid 30s, and Sat night/Sun am in the 30s to around 40F. SOme timing differences arise by Sun night/Mon, but overall expect increasing clouds ahead of the next front Sun night and will carry a chc for showers Mon/Mon night. Mild with lows in the 40s and highs Mon mainly in the 60s. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Wide variety of conditions tonight with primarily IFR to LIFR ceilings for the eastern half of the CWA and mainly clear skies/VFR west of I-95. Fog has also formed mainly east of I-95 across the area of low ceilings, fog may be locally dense at times. Conditions slowly improve during the day today with lower ceilings expected to linger near the coast through the early afternoon. Conditions will deteriorate once again Tuesday night as a potent upper level trough brings thickening and lowering clouds. Light winds will average 5 knots or less for the most part which will tend to keep an onshore flow at the immediate coast, but shifting to the S well inland. Outlook: Expect flight restrictions on Wed with snow showers as clipper and associated cold front crosses the region. Clearing Wed night with breezy N winds near the coast. Predominate VFR then likely Thu/Fri as the trough ejects NE offshore.
-- End Changed Discussion --
&& .MARINE... Late this aftn, ~1048mb high pressure is centered over ern Canada, and was ridging to the SSW along the piedmont. Also, weak low pressure was well off the Mid Atlc coast. This combination was still resulting in a NNE wind of 10-20 kt acrs the waters, with a few gusts near 25 kt just off the NE NC coastal waters. Seas were ranging fm near 4 ft nearshore, to as high as 8 ft out around 20 nm. SCAs are in effect until 7 pm this evening for the mouth of the Ches Bay and Currituck Snd, and until 15z Tue for seas for the coastal waters. The wind should diminish by Tue, as a weak surface ridge settles near the coast. A surface cold front crosses the coast Tue night, with strong CAA lagging behind until the upper trough arrives Wed evening into early Thu. The wind is expected to become N 10-20 kt Wed, and then NW 15-25 kt Wed night into early Thu. SCA conditions are likely for wind and seas. High pressure settles over the area by Thu aftn and Thu night, and then slides off the Southeast coast Fri. && .AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...None. NC...None. VA...None. MARINE...Dense Fog Advisory until 10 AM EST this morning for ANZ632>634- 636>638. Small Craft Advisory until 10 AM EST this morning for ANZ650- 652-654-656-658.
-- End Changed Discussion --
&& $$ SYNOPSIS...MAM NEAR TERM...LKB/MAM SHORT TERM...MAM LONG TERM...LKB AVIATION...AJB/LKB MARINE...TMG

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.