textproduct: Wakefield

WHAT HAS CHANGED

A Flood Watch has been issued for the Piedmont, central and southeast Virginia, and northeast North Carolina. The watch is in effect from 3 PM to midnight.

A Marginal Risk (level 1 out of 5) has been added for Thursday.

KEY MESSAGES

1) A Flood Watch is in effect for the Piedmont, central and SE VA, and NE NC this afternoon and evening. Widespread slow- moving showers and thunderstorms may lead to flash flooding, particularly in urban, poor drainage, and other flood prone areas. Storms could also approach severe levels with damaging winds the primary threat.

2) Near-normal temperatures are expected for most of this week. Additional chances for afternoon/evening thunderstorms continue with a Marginal Risk for severe thunderstorms added for Thursday.

DISCUSSION

As of 655 AM EDT Tuesday...

KEY MESSAGE 1...A Flood Watch is in effect for the Piedmont, central and SE VA, and NE NC this afternoon and evening. Widespread slow- moving showers and thunderstorms may lead to flash flooding, particularly in urban, poor drainage, and other flood prone areas. Storms could also approach severe levels with damaging winds the primary threat.

GOES mid and upper level water vapor channels depict a broad trough from the eastern Great Lakes through the Northeast, with the subtropical ridge now suppressed to our south. The surface pattern is rather nebulous. However, there is subtle boundary that extends from northern VA to the central Delmarva. The airmass remains very moist with the 07z SPC mesoanalysis showing PW values of 2.0-2.2".

The boundary will gradually push S today and become a focal point for showers/tstms by this afternoon and evening. The airmass will remain very moist with even EPS/GEFS ensemble guidance showing mean PW values of 2.2-2.3" by this afternoon. Overall forcing will be relatively weak, but our area is progged to be in the RRQ of a 65kt jet at 200mb along with some troughing at 500mb, which should be enough forcing given moderate to strong instability. The HREF and REFS remain consistent in showing a region with ~30% chc of 3"/3hr primarily along and S of the I-64 corridor, with localized pockets of 4-6" possible. This is where the Flood Watch covers. However, there could be some localized heavy rain front the Northern Neck to the MD Eastern Shore as well. There is also a marginal severe risk. However, lapse rates are weaker with more deep moist heavy rain soundings. Therefore, the severe risk should be less than prior days, and once again, the primary threat would be localized damaging wind gusts.

KEY MESSAGE 2...Near-normal temperatures are expected for most of this week. Additional chances for afternoon/evening thunderstorms continue with a Marginal Risk for severe thunderstorms added for Thursday.

A weak flow pattern very typical for the middle of summer with daily chances for showers/tstms continuing midweek into next weekend. Chance PoPs are forecast for Wednesday and Thursday (concentrated more inland Wednesday), with lower PoPs Friday with downsloping westerly flow. There is increased 500mb flow Thursday ahead of a shortwave trough, and a moist unstable airmass will be in place. Therefore, some strong to severe tstms are possible Thursday afternoon and evening. Temperatures will be near seasonal averages late this week into next weekend, ranging from the upper 80s to lower 90s. However, Wednesday will not be quite as hot with onshore flow behind Tuesday's front. Mid 80s are forecast Wednesday and evening some upper 70s are possible along the immediate coast of the Eastern Shore. Another front may cross the area Saturday with higher PoPs returning.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

As of 655 AM EDT Tuesday...

A stationary front extended from northern VA to SE MD as of 12z. LIFR cigs were observed with light NE flow at SBY. Elsewhere, patchy MVFR vsby was observed. Any MVFR vsby should improve by 13z. However, cigs at SBY will be slow to lift and may not lift to MVFR until ~16z. Additional showers/tstms are expected to develop this aftn and linger into this evening as the aforementioned boundary gradually pushes southward. Brief flight restrictions will accompany any showers/tstms, and mainly due to vsby restrictions in heavy rain. MVFR/IFR cigs are possible later tonight with onshore flow developing behind the front.

Outlook: MVFR/IFR cigs potentially linger Wednesday morning, especially along the coast. The best potential for showers/tstms Wednesday pushes farther inland with onshore flow. Chances of aftn/evening showers/tstms return Thursday, with the probability 20% or less by Friday, and 30-50% by Saturday.

MARINE

As of 330 AM EDT Tuesday...

Key Messages:

- Sub-SCA marine conditions are expected this week. Light southerly flow becomes NE and briefly increases to 10-15 kt Wednesday morning.

- Elevated winds and waves from strong thunderstorms are again possible this afternoon and evening.

Generally light flow is ongoing this morning. Benign conditions are expected to continue through tonight, outside of any thunderstorms which could produce locally higher winds and waves this afternoon and evening. A weak front will slowly drop south through the waters later this evening into tonight. This will shift winds to the E-NE across the waters. Additionally, 10-15 kt winds are expected on the north side of the front for a brief period Wednesday morning, with a few gusts to 20 kt possible on the ocean. Winds gradually relax heading into Wednesday afternoon, but remain onshore out of the E. The front will lift back N Thursday with sub-SCA S-SE flow Thursday, turning to the SW Friday into early Saturday. Another front is likely to drop S early Saturday with winds briefly becoming NW Saturday afternoon and then potentially NE Sunday.

Seas of 2-3 ft continue today into tonight. As NE winds increase Wednesday morning, seas are forecast to briefly build to 3-4 ft nearshore, with some potential for 4-5 ft seas in the far offshore waters of MD. Waves at the mouth of the bay may also increase to ~3 ft, with 1-2 ft elsewhere. Beyond Wednesday, seas return to a typical 2-3 ft with waves 1-2 ft in the bay and rivers.

EQUIPMENT

KAKQ radar is down due to mechanical issues without an estimated time of return.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Flood Watch from 3 PM EDT this afternoon through this evening for NCZ012>017-030>032-102. VA...Flood Watch from 3 PM EDT this afternoon through this evening for VAZ048-060>062-065>069-079>090-092-097-098-509>518- 520-523>525-528>531. MARINE...None.