textproduct: Wakefield

WHAT HAS CHANGED

A Severe Thunderstorm Watch is in effect through 10 PM for central, southern, and southeast Virginia, and southeast Maryland through 10PM this evening.

A Flood Watch has been issued for portions of central, southern, and eastern Virginia, and Southeast Maryland for tonight into Wednesday.

There is a Moderate Risk for excessive rainfall across southeast Virginia and northeast North Carolina late Wednesday through Thursday where flood watches will likely be needed.

KEY MESSAGES

1) Strong to severe thunderstorms are expected this afternoon and evening, along with the potential for localized areas of flash flooding through tonight.

2) The threat of severe thunderstorms will linger into Wednesday and the potential for torrential rainfall to produce scattered instances of flash flooding will also increase through Wednesday night and Thursday.

DISCUSSION

As of 350 PM EDT Tuesday...

KEY MESSAGE 1...Strong to severe thunderstorms are expected this this afternoon and evening, along with the potential for localized areas of flash flooding through tonight.

Showers/tstms have become more widespread across central VA this aftn well in advance of a cold front and potent upper trough. Deep layer shear has increased to 30-40kt and combined with 2500-3000 J/kg of MLCAPE has resulted in quickly developing updrafts. Instability is expected to remain high through the evening while the mid-level flow increases to 40-50kt. Therefore, a mix is line segments and semi-discrete cells remain possible through the evening. The main threat is damaging wind gusts. However, there is a risk for tornadoes (especially N and NE where SRH will be higher), and some initial cells late this aftn could contain large hail. A Severe Thunderstorm Watch is in effect through 10 PM this evening.

Fast storm motion will initially preclude significant flooding concerns. However, as the front slows this evening into tonight (and eventually Wednesday/Wednesday night) the flood threat will increase due to persistent rounds of showers/tstms. There is presently an axis of 2.0-2.3" of PW across central VA to the Eastern Shore, and this will linger overnight into early Wednesday morning. An initial Flood Watch has been issued from central VA to the lower Eastern Shore covering the threat tonight into Wednesday. This will eventually need to be expanded SE to cover the later Wednesday/Thursday time period.

KEY MESSAGE 2...The threat of severe thunderstorms will linger into Wednesday and the potential for torrential rainfall to produce scattered instances of flash flooding will also increase through Wednesday night and Thursday.

The severe threat likely continues into Wednesday, but with the higher probabilities shifted to the south and east ahead of the aforementioned southward-moving cold front. How convection evolves today/tonight will also influence the degree of cloud cover and destabilization potential on Wednesday. That said, the flow aloft is forecast to remain rather strong (40-50kt at 500mb). SPC has the Slight Risk outlined for our entire CWA (lvl 2/5).

Despite the ongoing drought conditions, Wednesday into Wednesday night is showing an increasingly confident signal for localized flooding, especially in urban and poor drainage areas. WPC has most of the area in a Slight Risk ERO again Wednesday with PW generally 2- 2.4", and a small Moderate Risk area will be issued for SE VA into NE NC. Additionally, a small Moderate Risk area will be introduced including NE NC Thursday. Decent flow aloft should keep individual cells moving but training storms on top of the rainfall received today/tonight could cause scattered instances of flash flooding. A Flood Watch will eventually be needed for SE VA and NE NC based on the latest data. All total, the QPF forecast through Thursday has generally 3-5", with locally higher amounts of rain from Richmond and Emporia eastward to SE MD and NE NC.

Some drier air finally moves back into northern portions of the region Thursday and Friday but some showers and storms will remain possible, mainly across the southern and southeastern portions of the area. Trending drier with below average temperatures by the weekend.

AVIATION /19Z TUESDAY THROUGH SUNDAY/

As of 155 PM EDT Tuesday...

Primarily VFR for the start of the 18z TAF period with some isolated to scattered showers/tstms producing brief MVFR conditions at RIC and SBY. Chances for showers/tstms ramp up by ~20z, especially from RIC to SBY. Strong- severe storms are also possible, which could bring heavy rain, frequent lightning, and strong wind gusts. Outside of storms, winds today will become gusty out of the SW to 20-25 kt. Showers/tstms gradually push ESE this evening primarily affecting RIC and SBY, and could linger into Wednesday morning. Chances of showers/tstms are less at ORF, PHF, and ECG. Some lower MVFR cigs are possible late tonight/early Wednesday morning, with brief IFR possible, mainly for RIC, SBY, and PHF.

Outlook: Another round of showers/tstms are expected Wednesday and Wednesday night, especially after 16z. Flight restrictions will be likely. A SW wind could gust to 20-25kt again Wednesday, especially at the southeastern terminals. Rain and storm chances shift south by late week, but could still impact KORF/KPHF down to KECG.

MARINE

As of 255 PM EDT Tuesday...

- Small Craft Advisories are in effect for the local waters from this afternoon into Wednesday.

- Strong thunderstorms are possible today and Wednesday, primarily during the afternoons and evening.

SW winds behind the warm front that moved across the area early this morning are just short of Small Craft Advisory criteria this afternoon at 15-20 kt in the Ches. Bay and 20-25 kt in the coastal waters. Winds will continue to gradually increase into the overnight as the pressure gradient tightens with winds peaking at 15-20 kt with gusts to 25 kt in the Ches. Bay, tidal rivers, and Currituck Sound, and 20-25 kt with gusts to 30-34 kt in the coastal waters. A few gusts around 35 kt will be possible past 20 nm, especially for the southern zones. These conditions continue into Wed morning, then diminishing Wed afternoon and evening. SCAs are in effect for all marine zones (excluding the 20-60 nm zones where SCAs are not issued) through 1 PM Wed for the Ches. Bay, Currituck Sound, and tidal rivers and 6 PM for the coastal waters. A surge of northerly winds is possible Wed night into early Thurs with gusts to 20 kt in the Ches. Bay, which could need another SCA. Lighter NE winds are likely Thurs afternoon and into the weekend.

Multiple rounds of thunderstorms are expected from today through Thurs morning. Some storms may be severe with strong, erratic winds. The highest risk is today through overnight across the VA and MD waters. Additional strong to severe storms are possible Wed into Thurs.

Seas build to 3-4 ft by this evening as the winds pick up with waves in the bay increasing to 2-3 ft. Seas of 4-5 ft for southern nearshore waters and 5-6 ft for the northern nearshore waters are forecast overnight (6-7 ft offshore). Waves up to 4 ft expected in the bay overnight. 5+ ft seas may linger as late as Wednesday night.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...Flood Watch through Wednesday afternoon for MDZ022>025. NC...None. VA...Flood Watch through Wednesday evening for VAZ048-060>062- 065>069-076>090-092-099-100-509>520-522>525-528. MARINE...Small Craft Advisory until 1 PM EDT Wednesday for ANZ630>632- 634>637-639. Small Craft Advisory from 7 PM this evening to 1 PM EDT Wednesday for ANZ633. Small Craft Advisory until 6 PM EDT Wednesday for ANZ650-652. Small Craft Advisory from 7 PM this evening to 6 PM EDT Wednesday for ANZ654-656-658.