textproduct: Wakefield

WHAT HAS CHANGED

Updated full discussion. No significant forecast changes.

KEY MESSAGES

1) Showers and storms late this evening into overnight will be capable of producing heavy rainfall, potentially leading to localized flash flooding. Additional showers and storms are expected Saturday, mainly near the bay and on the eastern shore.

2) Mainly dry with seasonable temperatures Sunday through Tuesday. Isolated to scattered diurnally driven convection returns by the middle to latter part of the week.

DISCUSSION

As of 230 PM EDT Friday...

KEY MESSAGE 1...Showers and storms late this evening into overnight will be capable of producing heavy rainfall, potentially leading to localized flash flooding. Additional showers and storms are expected Saturday, mainly near the bay and on the eastern shore.

The cold front that crossed the area last night is now stationary and has settled just to our south. A broad upper trough is over the Great Lakes and extends south over the Appalachians. A lead shortwave on the SE side of the trough is crossing the Piedmont, and is responsible for the showers and isolated storms that are tracking across western portions of the FA despite only a few hundred J/kg of MUCAPE. Scattered strong to severe storms have developed near the front from south central to southeast NC. The front is progged to move back north tonight as a warm front and bisect the area by early Sat AM. As a result, expect numerous showers and a few tstms to develop/move across southern VA and NE NC during the evening, before gradually spreading N and NE overnight. The highest precip chances shift to areas near the Bay and the Eastern Shore by sunrise on Saturday. Given the moisture rich airmass in place (PWs of 1.7- 2.1"), locally heavy rain is likely this evening-tonight, and a few areas could see 2-3" in a short time (mainly south of I-64). A Flood Watch was considered, but feel that the highest totals will be localized enough (and storms will be moving fast enough) for flash flooding to be isolated in nature. The 12z/21 HREF has 10% probs for 3" in 3 hours for mainly S/SE portions of the area tonight. A few strong to severe storms can't be ruled out near/south of the VA-NC border between now-9 PM, but confidence is low.

The front will continue to linger over east and northeast portions of the FA Saturday as the broad upper trough axis moves over the area. In addition, a weak surface low may develop along it in the vicinity of the Chesapeake Bay/Lower Eastern Shore. Additional showers and a few tstms are likely, especially from the Peninsulas to Eastern Shore. Convection will likely initiate earlier than usual and may even be ongoing during the morning. While the saturated profile and weak sfc heating (highs only in the low-mid 80s) should mitigate the severe wx potential, localized heavy rain/flooding is possible (especially near the bay and on the Eastern Shore). Similar to tonight, a few spots could see 2-3" of rain in a short time. WPC has maintained a Slight Risk of Excessive Rainfall for eastern portions of the area on Saturday.

KEY MESSAGE 2...Mainly dry with seasonable temperatures Sunday through Tuesday. Isolated to scattered diurnally driven convection returns by the middle to latter part of the week.

The weak front will finally move offshore, as the main upper level trough axis shifts offshore and surface high pressure builds into the SE CONUS. The surface high will usher in a drier airmass with seasonable temperatures in the 80s and dew points in the 60s Sunday into early next week. The high is progged to break down by Wed/Thu, with unsettled conditions and isolated-scattered aftn/evening convection returning mid to late week.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

As of 115 PM EDT Friday...

A frontal boundary has settled just to the south of the area early this afternoon. Mainly VFR north with VFR to MVFR CIGs in SE VA/NE NC. Showers with isolated tstms have developed well to the S/SW of the terminals. Conditions will remain VFR to high- end MVFR through late aftn. CIGs lower to 500-2000 feet (lowest at RIC) tonight as that front moves back to the north as a warm front. In addition, numerous showers/tstms are expected to develop and/or move across southern VA/NE NC between 00-06z. Brief LIFR VSBYs are possible with perhaps localized gusts to 25-35 kt during the evening. Precip chances (showers w/ isolated tstms) increase at RIC/SBY overnight but strong to severe storms aren't expected. Still300, IFR VSBYs are likely in the heavier showers. Remaining unsettled on Saturday with additional showers/storms expected (best chance at SBY/PHF/ORF). CIGs gradually improve to ~2000 ft by early Sat aftn.

Outlook: Eventually drying out later Saturday night and Sunday, with VFR conditions returning Sunday morning through Monday.

MARINE

As of 230 PM EDT Friday...

Key Messages:

- Generally benign marine conditions expected through the weekend, outside of afternoon/evening thunderstorms.

Afternoon weather analysis shows NNE wind prevailing around 10kt with gusts upwards of 15kt across the waters. Seas remain low at this time with wave heights around 1-2 ft across the bay and 2-3ft across our nearshore zones and 3-4ft further offshore. Winds are forecasted to shift later this afternoon and evening as a warm front lifts towards the area. Winds are expected to remain around 10kt with the shift and will be out of the E. In addition, the front will bring showers and thunderstorms that could pose the risk of wind gusts greater than 34kt and lightning. In terms of wave heights not expecting much change in them. By Saturday, southerly flow will return, then becoming SW by Saturday evening. Confidence continues to increase that a cold front will cross the waters late Sunday night allowing for northerly winds to return to our waters, These winds are forecasted to last through Monday.

Low risk for rip currents is expected through the weekend and into Monday.

AKQ WATCHES/WARNINGS/ADVISORIES

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