000 FXUS61 KAKQ 200758 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 358 AM EDT Tue Apr 20 2021 .SYNOPSIS... High pressure remains over the region this morning, and slides offshore by this afternoon and tonight. A cold front crosses the region Wednesday bringing another chance for showers and thunderstorms. Cool high pressure builds across the region Wednesday night through Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 400 AM EDT Tuesday... Zonal flow aloft prevails over the Mid-Atlantic region early this morning well downstream of a trough digging across the Northern Plains. At the surface, weak high pressure is centered across the Carolina and Mid-Atlantic Coastal Plain. Clear and cool early this morning with temperatures generally in the upper 30s to mid 40s, with readings in the upper 40s to low 50s along the coastlines. There is some patchy fog across the area. The high will be quick to slide off the coast today with zonal flow aloft. This will allow for a moderating trend with high temperatures warming into the upper 60s/low 70s along the coast, with mid/upper 70s well inland under a mostly sunny sky. A SSW wind of 10-15 mph is expected by this afternoon, with the potential for gusts to 20-25 mph from central VA to the Eastern Shore. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... As of 400 AM EDT Tuesday... The longwave pattern becomes increasingly more amplified tonight into Wednesday as the aforementioned trough digs into the Great Lakes. Southerly flow ahead of an approaching cold front will result in a milder night with forecast lows in the low/mid 50s. Still mostly clear this evening, with clouds increasing overnight along with a slight chance of showers over central VA and the Piedmont late. Surface low pressure is expected to track west of the Appalachians into the Northeast by Wednesday afternoon and evening. The cold front associated with the low will cross the area from west to east during the day clearing the coast by Wednesday evening. Scattered showers/tstms are expected along and ahead of the cold front. The best dynamics will be across the N/NE part of the forecast area, which may result in some of the storms being on the stronger side. SPC has maintained much of the region in a marginal risk for severe tstms, except for the far western Piedmont counties. Any showers/tstms are expected to be quick moving and hence QPF will is lilted. A SW wind ahead of the front will become breezy Wednesday morning into the afternoon with gusts of 25-30 mph expected, and potential 30-35 mph over the Eastern Shore. Breezy conditions will continue near the coast Wednesday night with NW flow after the front passes. High temps Wednesday afternoon will range from the upper 60s W to the mid and upper 70s SE. Any lingering showers quickly move offshore Wednesday evening as the front moves off the coast, and strong high pressure builds in from the W. Temperatures will plummet overnight into early Thursday morning. Freeze headlines are possible over inland portions of the area with low temps in the lower 30s expected. It will remain cool and dry during the day on Thursday with high temps only making it up to the upper 50s to lower 60s. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 400 AM EDT Tuesday... One more cold morning expected on Friday with high pressure over the SE states. Low temps will be in the mid to upper 30s for most, and lower 40s near the coast. Plenty of sunshine on Friday with mostly clear skies expected. Afternoon high temps in the mid to upper 60s. Low pressure originating in the four corners region will advance to the deep south by late Friday and then up to the Mid-Atlantic by late Saturday into early Sunday. Showers and thunderstorms are expected, with the highest chances during the second half of Saturday into early Sunday morning. High pressure and drier conditions expected for the second half of Sunday into early next week. High temps Saturday through Monday in the upper 60s to lower 70s, although Saturday could be a few degrees cooler in the Piedmont if clouds/showers arrive earlier in the day. Low temps Saturday night are expected to only fall into the 50s, with mainly 40s expected by Sunday/Monday nights. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... As of 155 AM EDT Tuesday... Weak high pressure extends from eastern NC through the Delmarva as of 06z. Clear with a calm to very light wind. Patchy ground fog has developed across the area, and is affecting SBY/PHF/ECG. Vsby is expected to average less than 3sm through 10-12z at these sites, but expect substantial fluctuations from LIFR to even VFR. RIC/ORF have less potential for fog, but some MVFR and brief IFR vsby are possible from 09-12z. High pressure slides offshore later this morning, with a SSW wind of 5-10kt developing across much of the area. This should allow any fog to quickly clear after 12z. A SSW wind of 8-12kt is expected by afternoon, with occasional gusts to 15-20kt from RIC to SBY. Remaining mostly clear this evening, with mid and high clouds increasing later tonight, along with a slight chc of showers at RIC after 06z Wednesday. A strong cold front crosses the region Wednesday afternoon. This will bring the potential for showers/tstms, with the best chance at SBY. Locally strong wind gusts and hail are possible with any tstms. Breezy outside of showers/tstms with a SW wind of 12-15kt gusting to ~25kt. The wind shifts to NW behind the front Wednesday evening, with breezy conditions continuing along the coast. High pressure returns Thursday and Friday. Low pressure approaches from the SW Saturday. && .MARINE... As of 700 PM EDT Monday... Winds have rapidly dropped off over the Bay and coastal waters N of the VA/NC border. Will maintain SCA headlines for the coastal waters S of Cape Charles as seas have risen to 4-5 ft in VA and up to 6-7 ft in NC waters. Will also keep SCA's going in the Currituck Sound for winds to 20kt+ for another 1-2 hrs before the sfc low pulls farther offshore. High pressure builds back in from the W overnight, before sliding offshore Tuesday and Wednesday. This should allow for winds to continue to diminish even over the NC waters later this evening, then veering around to the S 10-15kt later Tuesday afternoon into Tuesday night, as the high moves offshore. The wind may briefly reach SCA criteria 15-20kt in the lower Bay and lower james late Tuesday afternoon into Tuesday evening, but will hold off w/any additional headlines with SCA flags already in place at present. Thereafter, biggest marine impact for the period will be with a strong cold front that approaches from the W Wednesday. The front still on track to quickly move across the area later Wednesday afternoon. SCA conditions are likely in the wake of this cold front Wednesday night with a NW wind of 20-25kt with gusts to ~30kt. In- House Wind Probs highlight a rather brief period (< 3 hrs) of Gale Force gusts to ~35kt possible for the open ocean zones N of Cape Charles and over the middle Bay N of New Point Comfort. Seas build to 5-6ft, with 3-4ft waves in the Bay. High pressure builds across the Southeast Thursday and Friday as low pressure lingers well NE of the region, with seas slowly subsiding into the upcoming weekend. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...AJB/CMF NEAR TERM...AJZ SHORT TERM...AJZ/CMF LONG TERM...AJZ/CMF AVIATION...AJZ MARINE...AJZ/LKB/MAM