textproduct: Wakefield

WHAT HAS CHANGED

WPC has introduced a Marginal Risk (level 1/5) Excessive Rainfall Outlook for strong to severe storms across the northern half of the area today and tonight.

KEY MESSAGES

1) Becoming more unsettled late this afternoon into the weekend, with chances for showers, thunderstorms, and localized heavy rain.

2) Drier early next week as an upper ridge builds into the region, bringing above-normal temperatures.

DISCUSSION

As of 245 PM EDT Thursday...

KEY MESSAGE 1: Becoming more unsettled late this afternoon into the weekend, with chances for showers, thunderstorms, and localized heavy rain.

Latest surface analysis reveals a 1024 mb surface high near Bermuda. To the north, a dampening upper trough and surface low continue to cross the St. Lawrence Valley. The associated cold front extends southwest into the eastern Ohio Valley. Ahead of this boundary, sunny skies across the local area have pushed afternoon temperatures into the upper 80s to lower 90s inland ( lower 80s along the coast).

Mesoanalysis shows deep layer shear of 20-30 kt (highest NNE). 500700 J/kg MLCAPE across northern and central VA piedmont zones, though a capping inversion (75-100 J/kg CIN) remains over much of eastern VA and the MD/VA Eastern Shore per 18z analysis. CAMs continue to show MLCAPE increasing to ~1000 J/kg by early evening as the front edges closer to the area, and the time-lagged HRRR still looks to initiate some loosely organized convection late this afternoon (2022z / 46 PM EDT), focused along a pre-frontal trough just to our NW, aided by a weak shortwave crossing the Central Appalachians and pushing into northern portions of our area this evening. A few organized storm cores capable of localized damaging wind gusts remain possible through 10p-midnight, primarily across northern zones. SPC has maintained a Marginal Risk (Level 1/5) for this threat.

The cold front drops south into the region late tonight, with the front stalling across southern VA and NE NC Friday afternoon. The 12z HREF PMM highlights a 30% signal for 3"/3-hr QPF along and south of this boundary. Localized downpours and some localized flash flood issues remain the primary hazard, focused south of US-58. The Day 2 ERO has been adjusted east to cover more of the area mainly along and south of US-460 in southern/SE VA and northeast NC. Temperatures will feature a relatively sharp gradient Friday, ranging from the low 80s north to lower 90s south.

Widespread precipitation chances peak Saturday, as the stalled boundary lifts back north as a warm front, as a couple of weak mid-level shortwave disturbances push across the area. High precipitable water values, modest instability (skinny CAPE profile), and weak steering flow should yield efficient warm rainfall processes and additional localized hydro concerns (supported by an area-wide WPC ERO Marginal Risk). Considerable cloud cover will keep a lid on Saturday highs to the low to mid 80s. The boundary washes out Sunday, leading to noticeably lower convective coverage and warming temperatures early next week.

KEY MESSAGE 2: Drier early next week as an upper ridge builds into the region, bringing above-normal temperatures.

Mostly sunny and dry conditions return Monday and Tuesday as an upper-level ridge centered near the Gulf Coast expands northward. Highs will return to the upper 80s and lower 90s, with rain chances remaining below 20% (isolated late-afternoon shower possible in southside Hampton Roads and coastal NE NC Monday). Diurnal shower and thunderstorm chances gradually tick back up mid-to- late week as heat and moisture continue to build.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

As of 730 PM EDT Thursday...

VFR conditions in place across area terminals to begin the 00z TAF period look to prevail through tonight and Friday, with the exception of some scattered convection at RIC and SBY this evening into tonight.

A weak cold front approaches the region from the NW tonight with some isolated to widely scattered showers and storms at RIC and SBY through early Friday morning. Low confidence on coverage and timing still limits mention to PROB30 groups. Brief reductions to MVFR or locally IFR conditions is possible in any convection that manages to impact the terminals. Additionally, some MVFR CIGs and showers are possible Friday morning at SBY as the cold front drops into the northern portion of the area. Another round of showers and storms are possible Friday afternoon/evening, with the best chances at ECG.

Outlook: The boundary slowly drops south and lingers/meanders near the VA/NC border through Saturday night/early Sunday. Daily chances of showers/storms persist through this period, highest chances southeastern terminals and greatest on Saturday. MVFR (LCL IFR) CIGs will also be possible from PHF- ORF-ECG Friday night into Saturday morning, with additional opportunities of sub-VFR CIGs/VSBY in scattered to numerous convective showers and embedded t-storms Saturday afternoon and evening.

MARINE

As of 245 PM EDT Thursday...

Key Messages:

- A period of generally benign marine conditions is favored from this weekend through next week.

A cold front is draped across the Great Lakes region that is attached to a strong low pressure over the Hudson Bay. High pressure remains parked offshore, but with the aforementioned low lifting further away, the gradient across the local waters has weakened some since this morning. Winds have come down to below Small Craft Advisory criteria, so have let all SCAs expire. A few stronger gusts are being observed in the lower Bay, but all sustained winds are between 10-15 kts, so have maintained no headlines. Current observed wave heights across the coastal waters have also subsided quickly due to the offshore flow, with generally 2-4 ft being measured. Waves in the Bay are before 1-2 ft.

As the cold front slowly moves south across the local waters tonight into early Friday morning, SW winds may briefly increase ahead of the front to 15 kt across the lower Ches Bay and southern coastal waters. However, this surge looks to be brief with low confidence in SCA conditions across the lower Ches Bay and Currituck Sound, especially due to the SW wind flow. Winds become NE 10-15 kt with gusts up to 20 kt behind the cold front Fri. While some CAMs show 15- 20 kt winds behind the front, the CAA is weak with most guidance showing winds remaining below SCA. The flow becomes onshore Friday night into Saturday, with winds of generally 10 kts through Saturday night. Otherwise, a period of sub-SCA marine conditions is favored through early Monday. Another frontal passage is possible later on Monday, though winds quickly shift to the east so the period of any CAA looks to remain minimal. Despite an increase in winds in the wake of the front, winds as of now are forecast to remain sub- SCA after the front and through the remainder of the week. Overall, generally benign marine conditions are forecast through the entire forecast period. Waves and seas will likely remain 1-2 ft and 2-3 ft from late tonight into early next week.

The rip current risk will remain low through Friday, with the northern beaches bumping up to moderate on Saturday as flow becomes onshore in the wake of the cold front.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...None.