Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 260003 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 803 PM EDT Tue Oct 25 2016 .SYNOPSIS... Cool Canadian high pressure remains over the region through Wednesday. A cold front approaches from the northwest Thursday afternoon and crosses the area during the evening. High pressure returns Friday. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 1037mb high pressure is centered n of the Great Lakes this afternoon and is ridging sewd into the Mid-Atlantic region. The sky is sunny this aftn with only a few cu over the Lower MD Ern Shore. Temperatures are mainly in the low 60s across the region with dewpoints in the 30s. The high continues to build in from the nnw tonight. This appears to be the coldest night so far this season, with lows ranging from the mid/upper 30s over much of the area, to the low/mid 40s for coastal se VA/ne NC. This will bring the potential for frost except along the coast. Some high clouds could push into the Piedmont overnight, which could limit frost potential for the Piedmont. The highest confidence for frost is over the MD Ern Shore where a frost advisory has been issued. Patchy frost has been highlighted in the HWO for the Piedmont and Interior Coastal Plain. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Continued cool Wednesday under a partly to mostly sunny sky. 850mb temperatures moderate to +3 ne to +7 sw. However, this will be offset by the combination of high pressure over the region and low-level ne flow, which will limit mixing. Forecast highs are in the mid/upper 50s ne, to low 60s sw. The surface high gradually pushes offshore Wednesday night as low pressure tracks toward the Great Lakes. The surface ridge axis remains near the coast much of the night, so lows will still be cool under a mostly clear to partly cloudy sky ranging from the upper 30s over the Lower MD Ern Shore to the low 40s elsewhere. Shortwave energy will lift through the Great Lakes Wednesday night into Thursday, with the trailing cold front approaching from the nw Thursday aftn and crossing the area Thursday evening. Clouds increase early Thursday with much of the area becoming mostly cloudy to overcast. Chc PoPs (30-40%) for showers spread across the nrn half of the area by afternoon. The better potential for showers will be with the front Thursday evening, with ~60% PoPs from the Nrn Neck to the Ern Shore, and 30-40% elsewhere. Moisture is limited with this system, so current QPF through 12z Friday is aob 0.15". Highs Thursday range from the low 60s nw to near 70 se. The front pushes offshore late Thursday night into early Friday morning, with high pressure returning by aftn. Clouds are expected to decrease Friday with most of the area becoming mostly sunny by late morning and aftn. Lows in the upper 40s to mid 50s Friday morning will be followed by highs in the mid 60s to around 70. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Surface high pressure slides south of the region Saturday, centering along the Southeast coast. Shortwave ridging aloft builds over the eastern US. The result will be deep layer southwest to west flow and warming temperatures. 850Mb temperatures warm to around 12-14C (+1 standard deviation) Saturday. Have trended temperatures warmer, with highs generally in the low to mid 70`s. Cooler Eastern Shore. Medium range guidance now in better agreement with pushing a northern stream shortwave across the Northeast states Sunday. A dry cold front is progged to drop into the region Sunday afternoon into Sunday evening, but not before temperatures warm into the mid (possibly upper) 70`s. Trough axis pushes offshore Sunday night along with the dry cold front. Upper/surface high pressure returns to the region Monday. Highs in the mi to upper 60`s. Heights begin to build again across the Southeast and Mid-Atlantic as upper level high pressure over the Gulf of Mexico builds northward. The result will be another warming trend with highs back into the upper 60`s to low 70`s Tuesday. Mild overnight temperatures expected through the period, with lows generally in the upper 40`s to low/mid 50`s. The exception will be Saturday night, when lows are in the mid to upper 50`s. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... A ridge of high pressure extending south from Canada into the Mid Atlantic States will dominate over the Mid Atlantic States through the 00Z TAF period. This ridge will shift slowly toward the coast by late Wednesday. Light winds will prevail through the period which will gradually veer from northwest or north to northeast and eventually to east to southeast at RIC. OUTLOOK...High pressure slides off the coast late Wednesday night into Thursday morning and there could be some patchy fog as low- level moisture increases. A low pressure system moving from the Midwest to the Northeast States will drag a cold front through the region Thursday evening. High pressure returns Friday and Saturday and settles off the coast as another cold front approaches from the west on Sunday. && .MARINE... Latest surface analysis centers ~1028mb high pressure over central Virginia. The result is a northwest wind of 10-15 knots over the waters. Seas have dropped to 2-4 feet and waves 1-2 feet. All headlines have been allowed to expire. High pressure remains west of the waters tonight, with hi-res guidance indicating marginal SCA conditions for the Bay. While the cool and dry air mass may support stronger winds, the gradient is rather meager. Have opted to cap winds at 15-17 knots in the Bay with no headlines anticipated. However, cannot rule out a few gusts to 20 knots in the upper Bay. Waves build to 2-3 feet tonight and seas 3-4 feet. The surface ridge builds over the waters Wednesday and pushes offshore Wednesday night ahead of the next cold front. Gradient ramps up Thursday resulting in south to southeast SCA winds of 15-25 knots Thursday afternoon. Waves build back to 2-3 feet and seas 3-5 feet. The front pushes across the waters late Thursday night with SCA conditions expected. Northwest winds increase to 15 to 25 knots. Waves 2-4 feet and seas 3-5 feet. High pressure returns to the waters Friday afternoon. Medium range guidance now in better agreement with keeping high pressure over the Southeast coastal plain Saturday and Saturday night. A cold front crosses the waters late in the weekend into early next week. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Frost Advisory from 3 AM to 9 AM EDT Wednesday for MDZ021>024. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...AJZ/JDM NEAR TERM...AJZ SHORT TERM...AJZ/JDM LONG TERM...SAM AVIATION...LSA MARINE...SAM is the U.S. government's official web portal to all federal, state and local government web resources and services.