textproduct: Wakefield

WHAT HAS CHANGED

The Flood Watch is in effect now until midnight.

SPC has introduced a Slight Risk (level 2 of 5) for central portions of the area today.

KEY MESSAGES

1) The Flood Watch is in effect for central and eastern VA and interior NE NC today. Widespread slow-moving showers and storms may lead to flash flooding, particularly in urban, poor drainage, and flood prone areas. Storms could also approach severe levels with damaging winds the primary threat.

2) Additional storms capable of flash flooding and damaging winds are possible Tuesday afternoon and evening.

3) Near-normal temperatures are expected for most of this week, with additional chances for afternoon/evening thunderstorms.

DISCUSSION

As of 300 PM EDT Monday...

KEY MESSAGE 1...The Flood Watch is in effect for central and eastern VA and interior NE NC today. Widespread slow-moving showers and storms may lead to flash flooding, particularly in urban, poor drainage, and flood prone areas. Storms could also approach severe levels with damaging winds the primary threat.

Showers and storms this afternoon will bring the potential for heavy rain and localized flash flooding. A very moist air mass is in place over the area with meso-analyzed PWATs of around 2.0", with greater than 2.0" values along the coast. Despite weak forcing, moderate- strong instability, diffluent flow aloft, a weak low at the surface, and any remnant convective boundaries will support the development of rather widespread showers and storms this afternoon and evening. Showers and storms have begun developing, playing off outflow boundaries from previous storms causing very slow movement in some places. This is expected to be seen more throughout the night as more meso-boundaries develop. With the slow moving storms and ample moist atmospheric profiles, prolific rain rates are possible bringing heavy rainfall. The latest HREF and REFS continue to show an impressive signal for 30% chance of 3"/3hr across most of the area with rainfall totals of localized 4-6". These rainfall amounts could quickly lead to flash flooding, particularly in urban and poor- drainage areas, despite antecedent conditions being mostly dry. However, should note that some spots have seen higher rainfall totals over the past few days and these locations could be at higher risks for flooding today. Since convection has initiated early, the Flood Watch has been allowed to start early, in effect now until midnight.

Given the ample amounts of instability, strong low-level lapse rates (at least initially), and more shear than yesterday (~20kt of effective bulk shear), isolated storms may become strong to severe with damaging wind gusts as the primary threat. SPC has introduced a Slight Risk (level 2 of 5) for central portions of VA this afternoon/evening to account for the potential. The severe threat should generally diminish after sunset, with an increasing focus on the heavy rain threat after that time.

KEY MESSAGE 2...Additional storms capable of flash flooding and damaging winds are possible Tuesday afternoon and evening.

A similar set up to today will take hold Tuesday, which could bring more instances of flash flooding and damaging winds to the area. The environment will remain saturated with PWATs around or above 2.0", despite the convection today, as the stationary front lingers over the area and SW winds continue to pump in moisture. The HREF and REFS show another signal of 30-50% of 3"/3 hr of rainfall across central and SE portions of the area. WPC maintains a Marginal ERO and SPC a Marginal severe risk Tuesday for the majority of the area, but would not be surprised if subsequent updates include updates.

KEY MESSAGE 3... Near-normal temperatures are expected for most of this week, with additional chances for afternoon/evening thunderstorms.

A weak flow pattern very typical for the middle of summer with daily chances for showers and storms continues into the midweek period. Chance PoPs are in place Wednesday and Thursday, with lower PoPs Friday. Temperatures will be near seasonal norms for most of next week, ranging from the upper 80s to lower 90s. A weak front will cross the area Wednesday, resulting in the coolest day this week with high temps in the mid 80s. Another front may cross the area Saturday with higher PoPs returning.

AVIATION /18Z MONDAY THROUGH SATURDAY/

As of 150 PM EDT Monday... VFR conditions start the 18z TAF period, becoming degraded throughout the night. Another round of showers and storms is expected this afternoon and evening, with the highest confidence over RIC. Locally higher winds, heavy rain, frequent lightning, and reduced VSBYs are likely within storms. Storms may linger through early morning, but should be over by ~06z. Behind the convection, lowered CIGs are likely at RIC and SBY from the early morning until after sunrise (~06-15z), possibly lingering longer at SBY. MVFR CIGs are likely during this timeframe with locally IFR CIGs at SBY. Winds are generally out of the S-SW becoming light overnight behind convection.

Outlook: Additional thunderstorms are likely Tuesday and Wednesday. Localized flight restrictions would be expected in storms, but prevailing VFR is expected outside of storms.

MARINE

As of 300 PM EDT Monday...

Key Messages:

- Sub-SCA marine conditions are expected to prevail early to mid- week, with mainly south-southwesterly winds today gradually becoming east-northeast by mid-week.

- Elevated wind gusts from strong thunderstorms are possible during afternoon and evening hours today and Tuesday.

This afternoon, high pressure continues to extend from the Southeast US to off the Mid-Atlantic coast. There is a weak, nearly stationary front draped just north of the local waters, extending back into southern MD/northern VA. Outside of any localized outflow from shower or storms, winds are primarily S-SW and average 5 to 10 knots. Winds become SSE and increase slightly later this afternoon into this evening before becoming SW again later tonight. Scattered thunderstorms develop throughout the afternoon and evening hours which will have the potential to produce locally strong wind gusts. The boundary to the N today will gradually settle into the region by Tuesday. The wind will be light, and primarily NE to the N of the boundary, and SSW to the S of the boundary. Additional scattered shower/storms are expected again Tuesday afternoon and evening, with any storms again having the potential for locally strong wind gusts. The latest guidance has the boundary dropping S of the region Wednesday as a weak cold front. The wind becomes ENE 8-12kt. The front lifts back to the N Thursday, with sub-SCA S/SE flow Thursday becoming SW Friday and remaining sub-SCA.

Seas will be ~2ft through Tuesday, with 1ft to occasionally 1-2ft waves in the Ches. Bay. Seas build to 2-3ft by Wednesday, and potentially ~3ft coastal waters/3-4ft offshore waters given onshore flow, with 2-3ft waves in the mouth of the Ches. Bay, and 1-2ft waves elsewhere. Seas subside back to 2-3ft later in the week with 1- 2ft waves in the Ches. Bay.

EQUIPMENT

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

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Flood Watch until midnight EDT tonight for NCZ012>014. VA...Flood Watch until midnight EDT tonight for VAZ048-060>062- 064>069-075>090-092-097-098-509>525-528>531. MARINE...None.