textproduct: Wakefield

WHAT HAS CHANGED

Slight Risk for severe weather has been added for the Northern Neck and Eastern Shore for Thursday.

Updated Marine Discussion, no significant marine forecast changes

KEY MESSAGES

1)Showers and thunderstorms persist this afternoon potentially leading to isolated Flash Flooding and perhaps a strong to severe wind gust.

2) Slightly warmer summertime temperatures return Thursday and Friday. Meanwhile, a more progressive upper level pattern develops Thursday and Friday. This will bring a series of upper level disturbances, which will have the potential to trigger strong to severe thunderstorms each afternoon and evening. There is also a risk for excessive rainfall and flash flooding across northern portions of the area Thursday.

3) Near-normal temperatures are expected this weekend into early next week, with additional chances for afternoon/evening thunderstorms Saturday, before trending drier later in the weekend into early next week.

DISCUSSION

As of 339 PM EDT Wednesday...

KEY MESSAGE 1...A slow moving cold front will slowly drop through the region today. This will result in a localized risk for excessive rainfall and flash flooding. Additionally, a few strong to severe thunderstorms are possible across interior southern VA and NE NC.

Afternoon weather analysis shows weak zonal flow aloft across the eastern half of the United States. At the surface, a quasi-stationary front has been noted far south of the area and is currently in NC. Behind the front a modest warm and moist airmass is in place with temperatures in the low to middle 80s and dew points in the low to mid 70s. This environment is favorable for showers and thunderstorms that have already to begun to initiate along a secondary boundary that is draped across NE NC and stretching up along the route-15 corridor. This boundary will be the most favorable area for a storm to produce strong to severe downbursts as the storms will struggle to maintain themselves off the boundary due to the weak synoptics in place. In addition, very isolated flash flooding cannot be ruled out given a moist environment in place with PWATS between 1.9-2.2" and MLcape values between 1500-2000J/kg. Again the most favorable area would be along the boundary where storms can initiate and potentially train over the same area. For tonight, the showers and storms will decrease in coverage as day time heating is lost. Areas that receive rain could see the potential for patchy fog development tonight.

KEY MESSAGE 2...Hotter temperatures return Thursday and Friday. Meanwhile, a more progressive upper level pattern develops Thursday and Friday. This will bring a series of upper level disturbances, which will have the potential to trigger strong to severe thunderstorms each afternoon and evening. There is also a risk for excessive rainfall and flash flooding across northern portions of the area Thursday.

Models continue to hint on a slightly stronger mid/upper level flow Thursday and Friday. A 500mb trough is forecasted to be 30-35kt by Thursday afternoon ahead of a subtle shortwave, with similar values Friday ahead of a more potent shortwave. With the upper levels strengthening and strong diurnal heating a strong to severe wind gust cannot be ruled out each day. For Thursday severe threat the 12z CAMs have hinted on much stronger convection occuring over the Northern Neck and Eastern Shore. This makes sense as it is best colocated with strong instability and the left exit region of the weak jet steak. These portions could also see the highest potential of localized flash flooding as storms have the potential to train over the same areas. Friday continues to remain questionable as downsloping will occur giving the storms less coverage. In addition to the storms, temperatures are progged to climb into the upper 80s to mid 90s each day. These warm temps mixed with high dews will allow for heat indices to climb in the upper 90 to lower 100s. The best place for heat indices to reach 105 would be along the northern shore of the Albemarle Sound. With such low coverage of the 105 heat indices, no Heat Advisories has been issued at this time.

KEY MESSAGE 3...Near-normal temperatures are expected this weekend into early next week, with additional chances for afternoon/evening thunderstorms Saturday, before trending drier later in the weekend into early next week.

Afternoon/evening showers and thunderstorms chances continue through Saturday as a cold front pushed through the area. By the end of the weekend and into next week models hint on a drier patterns as high pressure returns to the area. Seasonally hot and humid Saturday, with high temperatures in the upper 80s to lower 90s. High temperatures trend down into the 80s Sunday and Monday, before a warming trend commences Tuesday into the middle of next week.

AVIATION /19Z WEDNESDAY THROUGH MONDAY/

As of 136 PM EDT Wednesday...

A mix of VFR and MVFR CIGS have been noted across the area this afternoon. SBY remains VFR while the rest of the terminals remain MVFR and low level clouds continue to clear. Latest satellite imagery shows the clouds clearing across the area and VFR CIGS should return to all terminals between 20-22z. In addition to the low CIGS, isolated showers and thunderstorms have initiated across portions of the Piedmont and NE NC. The thunderstorm near ECG ~1730z has started to weaken but could remain in the vicinity of the terminal for the next hour. Otherwise the showers should remain clear of the VA terminals especially ORF and PHF through the afternoon/evening. However, a shower/thunderstorm cannot be ruled out in the vicinity of RIC. Winds this afternoon remain out of the NE and E ~5-10kt. By tonight, winds become variable and a warm front lifts north. As this front lifts north a period of MVFR and IFR CIGS cannot be ruled out across NC and VA. These CIGS should clear by the mid to late morning of Thursday.

Outlook: Chances of aftn/evening showers/tstms return Thursday, with the probability 20% or less by Friday (better chances N/NW of an RIC-SBY line), then 40-60% by Saturday, and less than 30% Sunday.

MARINE

As of 250 PM EDT Wednesday...

Key Messages:

- Sub-SCA marine conditions are expected this week. E-NE 10-15 kt winds are expected through the rest of today.

- The risk of thunderstorms is lower today but increases again Thursday and Friday.

Benign marine conditions prevail through the forecast period. Winds this afternoon are E-NE at 10-15 kt on the north side of a slow moving backdoor cold front. Winds are expected to diminish slightly and shift out of the S-SE overnight at the front lifts north. Seas will be around 3 ft during this time and around 4 ft 20+ nm offshore. S-SE winds prevail into the early morning Thursday before shifting out of the W-SW during the afternoon and into Friday with 2- 4 ft seas. Winds swing around to the N-NW Saturday and then NE Sunday.

Daily chances for storms are anticipated through the week, however, the chance this afternoon is comparatively lower than the past few days. Chances for more widespread storms, some strong to severe, increase Thursday and Friday as the cold front progresses north. SMWs will be issued as necessary.

A moderate rip current risk is forecast today due to nearshore 3 ft waves and choppy surf. A low risk returns for the rest of the week.

EQUIPMENT

Repairs have been completed in the KAKQ radar and it is currently in service. However, some additional downtime will be needed tomorrow for some additional calibration.

AKQ WATCHES/WARNINGS/ADVISORIES

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