textproduct: Wakefield

WHAT HAS CHANGED

Updated full discussion. The threat for flooding continues through the evening south of I-64. Decreasing rain chances Wednesday through late this week.

KEY MESSAGES

1) A weak front and surface low lift slowly back to the north through tonight. The threat for flooding is greatest from now through the evening.

2) Convective coverage is expected to decrease Wednesday and especially late week into the weekend with warmer temperatures returning to the area.

DISCUSSION

As of 305 PM EDT Tuesday...

KEY MESSAGE 1...A weak front and surface low lift slowly back to the north through tonight. The threat for flooding is greatest from now through the evening.

A stationary front remains over the area this afternoon and is positioned from central to SE VA. A weak sfc low has begun to develop along the front. Meanwhile, an upper low is spinning over GA and a shortwave on the NE side of the low is moving north toward the area. As a result, numerous tstms have developed along the front (just south of the I-64 Corridor), which have prompted a few Flash Flood Warnings. Rain rates have been impressive (1.5"-2" in 30 mins as per gauges) given PWs on the order of 2-2.4". The storms will gradually propagate to the SW along outflows through the evening, with additional instances of flash flooding possible given the rain rates and weak deep layer flow. The low and attendant front are forecast to lift slowly northward through tonight. The front should make it to the north of the CWA by sunrise on Wednesday. Tstms will gradually decrease in coverage this evening with the loss of daytime heating, but showers will remain possible through the night with the front lifting north. The best precip chances shift to the Piedmont, northern neck, and eastern shore overnight. While the greatest threat for flooding will be from now-8 PM, isolated flooding can't be ruled out overnight. The weak winds aloft combined with widespread clouds will limit shear/instability and the chance for severe weather. Warm and humid overnight with lows in the upper 60s to low 70s.

KEY MESSAGE 2...Convective coverage is expected to decrease Wednesday and especially late week into the weekend with warmer temperatures returning to the area.

Showers and a few storms are possible Wednesday morning across the MD Eastern Shore. Then, the front and shortwave will move well to our north during the day. Upper heights also rise a bit as ridging over the Atlantic builds westward. Convective coverage on Wednesday will be much less than we are seeing today, with isolated to perhaps scattered aftn/evening storms possible across much of the area. WPC has maintained the Marginal ERO for much of the area. Precip coverage is expected to further decrease late week into the weekend as the upper trough to the west lifts northward and away from the area and ridging continues to build westward. With lower shower and storm coverage, temperatures return into the upper 80s and low 90s Thursday through Sunday. Afternoon heat index values climb back into the upper 90s and low 100s late week into the weekend. While apparent temps may briefly creep into Heat Advisory range (105+) in the afternoon, am not expecting the need for heat headlines at this time.

AVIATION /19Z TUESDAY THROUGH SUNDAY/

As of 125 PM EDT Tuesday...

A frontal boundary remains stalled from south-central to southeast VA early this afternoon. Showers and a few tstms have developed along it (INVOF PHF/ORF/RIC) with additional convection moving north toward ECG. Weak low pressure develops along the front as it lifts northward from late aftn-tonight. The front should move north of SBY by 12z Wed. Increasing coverage of showers and storms is expected this afternoon from central to SE VA. Confidence is low with respect to coverage and exact timing of convection at any one terminal so have PROB30 groups for now but will amend to TEMPOs as needed. Convection decreases across VA/NC this evening as the front moves north. Rain chances may increase at SBY later tonight. Another round of MVFR to IFR stratus is expected this evening-tonight (best chc of IFR is at RIC/SBY/PHF).

Outlook: Shower/storm chances continue on Wed, but less storm coverage is expected. A more typical Summer pattern returns for the latter half of the week, with a somewhat lower coverage of late afternoon and evening isolated to scattered showers and storms Thu-Fri.

MARINE

As of 305 PM EDT Tuesday...

Key Messages:

- Benign marine conditions are expected to prevail through late week, outside of local thunderstorm influences.

Expansive high pressure remains centered near Bermuda this afternoon. Locally, there is a weak stationary boundary that bisects the waters. The flow is on the weak side, generally around 10 kt, with the direction varying from the S-SE for the southern waters and the E-NE for the northern waters. There are also some showers and storms near the James River and lower Chesapeake Bay, but most of the activity today should remain over land or nearshore. Seas are around 3 ft, except ~4 ft in our 20-60 nm ocean zones. There are no headlines currently in effect.

The aforementioned front will lift slowly back to the north this evening into tonight and winds will shift to the S or SE (at ~10 kt) for all waters. Additional showers and storms will be possible in the Chesapeake Bay vicinity through the night as well. The front will linger across the area through Wednesday before starting to wash out. Locally degraded marine conditions are likely to accompany the stronger storms through mid-week, mainly in the form of visibility restrictions in heavy rain and frequent lightning, but some localized gusty winds and confused seas will also be possible. As the front washes out, weak high pressure will rebuild over the area, then slide offshore for late week. A more typical summer setup resumes, with Sub-SCA S-SW winds ~10-15 kt developing, turning S-SE nearshore with seabreeze circulations each afternoon. Daily afternoon and evening shower and storm chances persist into the weekend, though chances will be much lower Thursday/Friday and into the weekend.

Rip Currents: A moderate rip current risk looks to persist across the northern beaches through midweek, with a low risk for the southern beaches.

AKQ WATCHES/WARNINGS/ADVISORIES

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