Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 201100 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 600 AM EST Mon Feb 20 2017 .SYNOPSIS... High pressure over eastern Canada builds south across the region today, then slides offshore tonight and Tuesday. A frontal boundary stalls north of the area Tuesday night with low pressure tracking across the region Wednesday. High pressure returns Thursday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Latest MSAS has a 1020 mb high centered over the Ohio valley, a 1027 mb high centered up near Hudson Bay with a weakening dry boundary located across the nern states. Models basically wash this boundary out today as it sags southward while the high pressure systems merge across the region this afternoon. Just enough CAA noted on north winds to drop H85 temps to between 7-8C. Little if any moisture noted to support nothing more than sct-bkn CI. Upshot will be a sunny and continued mild holiday. Onshore flow keeps eastern areas coolest with highs ranging from the mid-upr 50s across the eastern shore, between 60-70 from the Ches Bay to the Piedmont with lwr 70s across swrn most zones (FVX-AVC). && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... The high slides offshore tonight. Tsctns show high level moisture increasing across the region after midnight due to the light onshore flow. Clear skies this evening become pt cloudy after midnight. Lows in the 30s to near 40 sern coastal areas. The offshore high still dominates Tuesday ahead of a weakening mid- level cold front approaching from the west. Pt to mostly sunny skies expected with the most sun across the se closer to the offshore ridge. Mixing will be limited, only to about 950-925mb, with highs ranging from the low-mid 50s near the water, upr 50s-lwr 60s west of the bay. The mid level cold front approaches from the west Tues night but stalls across the mts with a sfc trof extending east across the Piedmont. Moisture is limited, but latest guidance is a bit more bullish in allowing this moisture to spread east into the Piedmont after midnight. Thus, have added a low chc shwrs after midnight across northern and western areas of the fa, highest pops west of I95. Otw, mstly cloudy to cloudy with lows in the low-mid 40s. Models diverge with Wed forecast to a degree where it has become a low confidence forecast. NAM is a much wetter solution as it tracks low pressure and categorical pops across the region. GFS has a weaker system ahead of the sagging sfc trof with chc pops, SREF a model blend while the ECMWF keeps a low suppressed well to the south. Won`t get to fancy with timing and go with chc pops under cloudy to mstly cloudy skies. Lowered temps by several degrees due to more clouds and pcpn but temps still remain well above normal. Highs from the low-mid 60s near the water, upr 60s to nr 70 west of the Ches Bay. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... The models are in good agreement in the extended range showing a flat ridge over the eastern US for the second half of the work week. That ridge will amplify into Saturday as a trough lifts out of the central plains into the Great Lake states which will knock the ridge down by Sunday and return the area to more westerly zonal flow. Overall, this will lead to another period of above normal temperatures along with a chance for showers and psbl tstrms as the cold front crosses the area Saturday. On Wed night into Thursday as the high slides off the coast, the flow will turn sw and should see a good warm up ahead of a weak front that tries to drop in from the north. The guidance suggest the possibility of some light showers especially across the northern part of the cwa Thursday into Thursday night. But with the area having been dry for the last several weeks will not mention any chance of rain with this weak front as the ridging aloft may end up keeping the front just north of the area. Expect above normal temperatures with highs in the uppers 60s to the mid 70s. The next strong sfc low will lift from the central plains into the Great Lakes on Friday into Saturday dragging a cold front across the region on Saturday. The guidance is in better agreement for a swath of moisture and marginal dynamics with the fropa so went ahead and added thunder to the grids Sat. Behind the front, temperatures will return closer to normal but still above normal, but just not 20 to 25 above normal as Thursday into Saturday will be. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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VFR through the forecast period as high pressure dominates. SCT CI today becomes BKN tonight as moisture increases from the west. Winds NNE at or below 10 kts. OUTLOOK...Sct shwrs psble Tue night across the Piedmont. Addntl shwrs Wed as low pressure crosses the region. Shwrs/psbl tstrms Sat as a strong cold front crosses the area.
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&& .MARINE... Sub-SCA conditions continue today as sfc high pres slides in from the west. Brief CAA surge expected this morng in association with pres rises as the high builds in, but expect winds only up to ~15 kt. North winds then drop to ~10 kt later this aftn with 1-2 ft waves over the Bay and 2-3 ft seas over cstl wtrs. The high builds directly over the wtrs tngt into Tue with winds aob 10 kt. Sub-SCA S/SW flow then persists until Fri ahead of the next cold front, which crosses the wtrs over the weekend with SCA conditions psbl. && .CLIMATE... Record Highs for Thursday 2/23 and Friday 2/24: 2/23 2/24 RIC 75 in 1985 82 in 1985 ORF 79 in 1975 82 in 2012 SBY 74 in 1943 77 in 2012 ECG 77 in 1975 79 in 1985 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...MPR NEAR TERM...MPR SHORT TERM...MPR LONG TERM...ESS/MPR AVIATION...MPR MARINE...MAS CLIMATE...MPR

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