731 FXUS61 KAKQ 080049 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 749 PM EST Thu Dec 7 2023 .SYNOPSIS... High pressure builds south of the area through tonight, before pushing offshore Friday into Saturday. A strong frontal system likely impacts the region on Sunday. High pressure builds back into the region early next week. && .NEAR TERM /THROUGH FRIDAY/... As of 700 PM EST Thursday... The latest analysis indicates ~1023mb surface high pressure centered just off the coast of GA/SC. Aloft, mid- level ridging continues to build east of the Mississippi River as the upper trough over the Canadian Maritimes pushes farther offshore, bringing a WNW flow to the local area. There is some mid level moisture exiting off the Delmarva coast on the south side of an upper jet extending from western Quebec SE to off the northern mid Atlantic coast. Skies are BKN-OVC on the MD eastern shore, with mainly clear skies elsewhere. A light SW flow will prevail this evening, becoming light/variable inland and remaining SW at ~5 mph near the coast. It will be a bit milder than last night, but still on the cool side with lows mostly from 30-35F, with some upper 20s well inland and upper 30s/lower 40s at the immediate coast in SE VA and NE NC. The sfc high pressure remains centered off the SE coast, and gradually builds N closer to the local area overnight as the upper ridge axis moves east and becomes aligned just W of the CWA by daybreak Friday. Light return flow sets up for Friday, allowing high temperatures to warm several degrees warmer than today. A batch of BKN high cloud cover is likely as the upper ridge axis moves into the CWA, but the sky will still avg out partly-mostly sunny. Max temps will mostly range from the upper 50s to around 60F, except for lower-mid 50s across the eastern shore. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 715 PM EST Thursday... Remaining dry and mild Friday night through Saturday, as sfc high pressure expands to the N and becomes centered off the mid-Atlantic coast on Saturday. The upper level ridge axis also moves off the coast in response to a potent upper level trough extending from the northern Plains SW into the southern Rockies. Meanwhile, low pressure will begin to take shape over the central and southern plains Friday night, and will lift E-NE along a strong cold front Friday night into Saturday from the Gulf Coast up through the Ohio Valley. Low temperatures Friday night will range from the mid- low 30s NW to the low 40s across the S/SE. Saturday is shaping up to be a nice day with mostly sunny skies and high temperatures ranging from the upper 50s to lower 60s N to the upper 60s S. Clouds will be on the increase out ahead of the approaching system Sat night and it will be much warmer with lows in the upper 40s to mid 50s. A few showers may reach into western portions of the FA early Sunday. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 730 PM EST Thursday... All attention then turns to our next weather maker Sunday and Sunday night, as previously referenced strong cold front approaches and crosses the region. Out ahead of the front, PW values surge to 1.50"+ by late in the day Sunday into Sunday night. The overall trends in the model timing is similar for the day Sunday, then with the front slowing down a bit Sunday night and not pushing offshore until after 06Z/1am per most of the guidance, with a few GEFS ensemble members even suggesting the front does not move off the coast until close to 12Z Monday morning. The general thinking remains the same however, with a warm/breezy day Sunday with deep layered S to SW flow. PoPs increase from west to east after midnight late Saturday night into Sunday morning in the piedmont, into the day Sunday over the rest of the area. Highest rain chances still appear likely during the Sunday late afternoon to Sunday night time-frame. This system certainly has the potential to bring beneficial rainfall to the region, and the latest operation models including the GFS/CMC/ECMWF have in excess of 1.00" of QPF across the entire CWA and generally avg from 1.00-2.00" in total QPF through Monday morning, with the GEFS and EPS ensembles showing a 10-30% chc for >2.00". WPC has the entire region highlighted in a Day 4 Marginal ERO and we will need to keep an eye on the potential for at least some localized flooding, especially in flood-prone and urban areas. The concern for at least localized strong to severe storms continues to slowly build, as well. Given such a dynamic system and very strong winds just off the surface (latest GFS/ECMWF each depict 925mb winds cranking to ~45-50 kt Sunday evening).In addition, deepening sfc low pressure along the approaching front (on the order of 6-9mb/6hr) would likely aid in the backing of the low level winds Sun aftn/evening (to the S or even the SSE), further increasing directional shear and potential for at least a non- zero TOR threat. Availability of shear is not in question, either with 30-40 kt of 0-1km shear progged by both GFS/ECMWF. Rather, the primary challenge/issue is the degree of instability in the pseudo-warm sector ahead of the approaching frontal system, and this will need to be monitored over the next 2-3 days. For now, have included at least schc thunder chances for the entire area (and chc T over the SE). PoPs are categorical (80-95% late Sunday into Sunday night) with rain chances ramping back down Monday morning as the front crosses offshore. While SPC does not yet have our area highlighted, machine learning models continue to key in at the possibility of severe weather/damaging wind gusts across the region on Sunday. early morning data from both CIPS SVR Analog and the CSU Machine-Learning Page are each showing an increasing signal for SVR probs over the lower mid-Atlantic for this time frame. Stay tuned and pay close attention as we continue to refine the forecast over the next couple of days. Rain should come to an end quickly in the wake of the front late Sunday night into Monday morning, as high pressure builds back into the region. Becoming gusty behind the front on Monday with strong pressure rises and much cooler/drier air. Highs only in the 50s. Winds ease Monday night and Tuesday, with dry conditions and cooler temperatures to prevail through the middle of the week. Looks like conditions remain dry through at least Thursday. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 700 PM EST Thursday... VFR through the 00Z/08 TAF period. Generally SW winds at 5-10kt or less with just high clouds through Friday. Outlook: VFR/dry conditions prevail through Saturday. A strong cold front approaches from the west from Saturday night into Sunday, bringing our next chances for sub- VFR conditions and gusty winds, along with additional periods of locally heavy rainfall, especially Sunday aftn into Sunday night. Becoming dry and breezy Monday with W-NW winds. && .MARINE... As of 300 PM EST Thursday... High pressure is centered just off the coast of FL/GA this afternoon, allowing for winds to become SW ~15 kt this afternoon with the high remaining centered to our south. A weak sfc trough will track from NW to SE over the Northeast U.S. later today, which may result in an uptick in SW winds tonight to 15-20 kt. A Small Craft Advisory remain in effect this morning for the Chesapeake Bay and Atlantic Ocean coastal waters until 7 A.M. this morning. SCA will continue into the afternoon for ocean waters south of Cape Charles for seas around 5 ft. Gusty winds along the Chesapeake will be near 25 kt this evening and overnight, with an end to SCA gusts prior to sunrise Friday morning. The center of high pressure will move over the Atlantic Ocean on Friday and winds turn S and diminish to 10 kt or less. This will allow seas to further diminish to 2-3 ft and waves to 1-2 ft. Benign conditions continue for the first part of the weekend with the high remains just off the coast. Still looks like a strong storm system will impact the area on Sunday and into Monday. Strong southerly winds are expected on Sunday and a low pressure system track just inland from the coast. South winds with gale force gusts are possible through the day on Sunday and into Sunday night. The low pressure will continue to strengthen as it move north of the area and as cold air moves in. Therefore, gale conditions are also possible as winds become NW late Sunday night or Monday as the low tracks away from the area. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 1 AM EST Friday for ANZ630-631. Small Craft Advisory until 4 AM EST Friday for ANZ632-634. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB LONG TERM...LKB/MAM AVIATION...LKB MARINE...CP/MHX