Area Forecast Discussion
Issued by NWS Wakefield, VA

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447 FXUS61 KAKQ 211037 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 637 AM EDT Sat Oct 21 2017 .SYNOPSIS... High pressure remains over the Mid Atlantic region through the weekend...with temperatures gradually warming. The next cold front is expected to impact the region Monday night and Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Sfc hi pres sfc-aloft remains anchored invof FA through today. Other than patchy/areas of FG...esp in interior SE VA-NE NC...dry-continued SKC and seasonably warm wx expected again today. Winds remaining VRB mainly aob 5 kt. highs 75-80F...l70s right at the coast. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... High pressure slowly shifts off the coast tonight-Sun. Potentially a little better coverage of patchy/areas of FG by late tonight due to light ESE winds. Otherwise...dry-continued seasonably warm wx. A few more clouds possible by Sun afternoon due to the low level flow from the SE ahead of the next cold front (which will be entering the OH-TN valleys late) - so may become partly sunny vs mostly sunny. Lows tonight in the u40s-l50s inland to the m-u50s at the coast. Highs Sun ranging through the 70s. By Mon...low pres deepens over the Deep South/lower MS Valley while a strong upper ridge remains in place along/just off the East Coast. 00Z/21 GFS and ECMWF showing only very subtle timing differences with respect to how quickly the precip from the southern low is able to spread east into the Mid-Atlantic. Based on 00z/21 suite of models...keeping PoPs aob 20% throughout the local area. While PoPs tend to increase late in the day W...may also be tad higher area of PoPs near the coast in SE VA-NE NC toward Mon eve. Otherwise...clouds will be on the increase (gradually) from W-E Mon. Highs again in the m-u70s (l70s right at the coast)...after morning lows in the 50s-around 60F. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Still a lot of uncertainty as to how next weeks system plays out as models offer up different timing and moisture field solutions. What is agreed upon is that a full latitude trof will move across the region Tue, what is yet to be determined is the scope and track of several s/w`s embedded in the trof and timing of a cold frontal passage across the area. GFS slower/much wetter as copious amounts of GOM moisture gets transported north ahead of the front. ECMWF faster/drier with the fropa with a dry slot cutting the pcpn off. Decent low level jet and theta-e advection progged ahead of the front for at least some instability to develop. Went ahead and bumped up pops to between 70-80% late Mon night through 18Z Tue with pcpn tapering off and ending west to east late Tue aftrn and Tue night as the deepest moisture pushes offshore. Added moderate rain and slight chc thunder for Tue morning. Later shifts can adjust as needed. Warm and humid Mon nite with lows in the 60s. Breezy Tue with highs 70-75. Cooler Tue nite with lows in the upr 40s west to upr 50s along the coast. Slight chc pops Wed as upr level energy lingers. Cool with highs in the low to mid 60s. The upr level low lifts NE Thu allowing high pressure to build across the southeast. Dry Thurs and Fri. Highs Thurs in the low to mid 60s. Lows in the 40s. Highs Fri 65-70. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
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Predominantly VFR conditions expected through the 12Z TAF forecast period as sfc high pres dominates. Another round of patchy/areas of FG expected through early this morning...w/ potential for IFR/LIFR from time to time...esp PHF/ECG. Sfc hi pres shifts off the coast tonight-Sun. A little better coverage of FG possible late tonight/early Sun due to light SE winds. A cold front is forecast into/across the local area late Mon night and Tue w/ chcs for MVFR to lcl IFR conditions in RA and low CIGS.
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&& .MARINE... A large area of surface high pressure over the region will allow for generally benign conditions over the waters through the weekend. Winds generally are 5 knots or less over all of the coastal waters this morning. Winds become ENE by this afternoon and increase to 5 to 10 knots. Seas are expected to range from 1 foot or less in the Bay and rivers (1 to 2 feet at the mouth of the Bay) and 2 to 3 feet over the coastal waters. Favorable boating conditions continue into Sunday with with benign seas and ESE winds of 5 to 10 knots. The next chance for significant weather over the waters does not come until early next week as a strong cold front approaches from the west on Monday and slowly crosses the waters on Tuesday. The pressure gradient will lead to increasing southerly flow ahead of the front later Monday into Tuesday, shifting to the WNW behind the front Tuesday night into Wednesday. Small Craft Advisories will likely be needed for most or all of the area Mon night/Tue as the pressure gradient should be strong enough for winds of 15-25 kt with higher gusts. Coastal seas build to 6-9 ft with waves of 3-5 ft in the Bay likely. A fair amount of uncertainty remains Tue night/Wed regarding how strong the pressure gradient will be as the models tend to keep the cold air and strong winds off to our NW over the Great Lakes until Thu. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...ALB/JDM NEAR TERM...ALB SHORT TERM...ALB/JDM LONG TERM...MPR AVIATION...ALB/MPR MARINE...AJB/LKB is the U.S. government's official web portal to all federal, state and local government web resources and services.