Area Forecast Discussion
Issued by NWS Wakefield, VA
Issued by NWS Wakefield, VA
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450 FXUS61 KAKQ 130712 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 312 AM EDT Mon May 13 2024 .SYNOPSIS... Scattered showers are possible for the Eastern Shore this afternoon as an upper trough exits the region. Dry and warmer to start the work week before another round of showers and storms returns to the region Tuesday and Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 925 PM EDT Sunday... Key Messages: - Drying out tonight with some patchy fog possible on the eastern shore. - Warmer and remaining dry for Monday. An upper level trough is pushing off the Mid-Atlantic coast this evening. Mostly clear aside from some scattered lingering clouds over the MD Eastern Shore. Drying out overnight with a clearing sky along the MD coast behind the departing trough. Some patchy fog will again be possible late, this time on the eastern shore and perhaps also over the peninsulas of eastern VA and the interior tidewater. Early morning low temps fall into the mid to upper 40s inland (some lower 40s possible for the NW Piedmont), and the upper 40s to low 50s along the coast. High pressure over the coastal plain slides offshore on Monday, bringing warmer temperatures and dry conditions (briefly) back to the region. High temps climb back into the 70s to low 80s. Clouds start to increase by late in the afternoon from the SW ahead of our next system. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... As of 330 PM EDT Sunday... Key Messages: - Increasing clouds Monday night, with showers developing late over inland areas. - Next system moves in Tuesday with showers and thunderstorms. Widespread severe weather is not expected. - Showers and a few storms linger on Wednesday before moving offshore overnight. Rain chances quickly ramp up after midnight Monday night/early Tuesday and into the day on Tuesday. A closed upper low over the mid-Missouri Valley translates east into the Western TN Valley Monday night, with the system slowing and lingering across the TN Valley through midweek. Overrunning moisture pushes into the piedmont region west of RIC in the early morning hours Tuesday, reaching the I-95 corridor by midday, and the coast by mid- afternoon. Kinematics and relatively weak deep- layer shear would indicate only a modest chance for storms on Tuesday, with the overall severe threat even lower. However, will maintain a thunder chance through the afternoon on Tuesday over SW sections and along the SE coast into later Tuesday evening. QPF through Tue night between 3/4" and 1" of additional rainfall, with locally higher totals possible. Best chances for periods of locally heavy rainfall will be across south central and southeast VA into northeast NC Tue night, where secondary low pressure looks to develop Tuesday aftn, lifting a warm front across the region Tuesday evening. Better area of IVT and PW values AOA 1.5-1.75" (near climo daily maxes) then look to stream NNE across our SE coastal plain Tuesday evening, with showers and storms forecast. For its part the CSU machine learning probs do show a marginal risk area for its ERO forecast, which has been matched by WPC for day 3 (Tuesday). Rain briefly tapers off early Wednesday morning, especially across the S/SE, as mid-levels briefly dry out. However, we never really dry out lower levels through this period. This likely portends continued overcast/substantial cloud cover and light rain throughout Wednesday, as the closed low to the west opens up and the surface reflection weakens as it crosses the central/southern Appalachians. Precipitation character remains a bit more stratiform through the day for most. However, chances for storms do increase a bit over NE NC and perhaps into Hampton Roads by afternoon as the weakening upper low approaches. This allows for a period of increased deep-layer shear (25-35 kt) along with some decent instability (LREF does show 500-750 J/kg of CAPE by afternoon) in the pseudo warm sector across the SE. As high pressure builds to the north, the weakening surface low crosses the area Wed night, with the positively-tilted upper trough lingering over the area into Thursday. Given this timing, Wednesday night would then feature diminishing rain chances and drier air filtering into the region. Kept highs in the 70s for much of the area on Wednesday, with some lower 80s across the SE coast. Lows Wed night in the 50s to near 60. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 330 PM EDT Sunday... Key Messages: -Continued warm late this week with increasing chances for showers and storms later Friday and Saturday. High pressure builds in briefly on Thursday but another system approaches on Friday with another chance for scattered showers and storms, though the 12z suite of models is notably slower with returning moisture back into the local area, and have accordingly pushed PoPs a bit lower with this forecast package. High temps remain in the 70s to low 80s on Thursday and Friday with low to mid 80s on Saturday. Overnight lows continue around 60 degrees. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... As of 755 PM EDT Sunday... Weak low pressure is pushing off the coast as of 00z. VFR with a light NE wind of 5-10kt, and only some SCT but dissipating clouds around 6-8kft at SBY. Weak high pressure builds over the region tonight. The wind will become calm to very light out of the E tonight. Patchy fog is possible late tonight with the best chc at SBY. The current forecast has prevailing IFR vsby at SBY 07-11z, and tempo MVFR vsby at PHF 08-11z. Brief MVFR vsby is possible at ORF and ECG as well. High pressure slides offshore Monday. Sunny and VFR with a SSW wind inland and SE along the coast with speeds generally at or below 10kt. Low pressure returns Tuesday into Wednesday bringing showers, periodic flight restrictions, and possibly a few tstms. Conditions gradually improve Thursday into Friday. && .MARINE... As of 310 AM EDT Monday... Key messages: -SCAs have been issued for the Chesapeake Bay from this evening through early Tuesday morning for a brief period of elevated S to SE winds. -Additional SCAs are likely ahead of a low pressure system Monday Tuesday into Wednesday morning High pressure is centered near the waters early this morning with light E winds and ~3ft. The high gradually shifts offshore today, and winds then increase out of the S-SE (to ~15kt by late aftn) as the pressure gradient tightens on the back side of the high. Confidence in seeing a brief period of low-end SCA conditions on the bay has increased this evening-early Tue AM, and local wind probs now show a 70-90% chc of sustained 18kt winds between 6 PM today-2 AM Tue. Went ahead and issued SCAs for the bay that is in effect from 6 PM through 1-4 AM. S winds briefly diminish to 10-15kt Tuesday AM. However, a low pressure system will approach the area on Tuesday before crossing the area from west to east late Tuesday night/early Wednesday. The pressure gradient will increase ahead of the system by Tue aftn/evening, allowing S winds to increase to around 20kt (and remain elevated through most of Tue night). Local wind probs continue to show an 80-100% chc of 18kt winds on the bay Tue night. Wind gusts are expected to be right around the 25kt threshold on the ocean (and local wind probs for 25kt gusts are only 30-60% for a few hrs Tue night), but seas should build to 5ft by Tue night. Therefore, SCAs appear likely for the bay and ocean (and perhaps the Lower James/Currituck Sound) with this system. Sub-SCA conditions are expected behind the system Wed night-Thursday (w/ N-NE winds near 15kt and seas subsiding to ~4ft). Waves on the bay will be 1- 3ft through most of the period (although 4ft waves are possible Tue night). && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 6 PM this evening to 4 AM EDT Tuesday for ANZ630-631. Small Craft Advisory from 6 PM this evening to 1 AM EDT Tuesday for ANZ632-634. && $$ SYNOPSIS...MAM/RHR NEAR TERM...AJZ/MAM SHORT TERM...MAM LONG TERM...MAM/RHR AVIATION...AJZ MARINE...ERI