textproduct: Wakefield

WHAT HAS CHANGED

- Showers and storms are possible this afternoon and into the evening with drier conditions expected tomorrow.

- Rain and storm chances increase Thurs-Sat with around seasonable temperatures.

KEY MESSAGES

1) Showers and storms are possible this afternoon and into the evening with drier conditions expected tomorrow.

2) Rain and storm chances increase Thurs-Sat with around seasonable temperatures.

DISCUSSION

As of 334 PM EDT Tuesday...

KEY MESSAGE 1...Showers and storms are possible this afternoon and into the evening with drier conditions expected tomorrow.

Afternoon weather analysis shows weak zonal flow aloft, while at the surface a weak surface low has been noted across NE NC. With a close proximity of a surface low and many subtle boundaries across the area, isolated showers and thunderstorms have begun to initiate across portions of the area. The majority of the showers have initiated across SE Va and NE NC as they are in much closer proximity to the low. The showers and storm chances will continue through the evening but will remain quite isolated in nature. In addition, these storms will likely remain sub-severe, however, cannot rule out a strong to severe wind gust and very localized urban flooding given the hot and humid airmass in place. In terms of temperatures, cloud cover across the Piedmont and areas north of I- 64 have remained in the low to middle 80s. While across the SE temps have reached into the upper 80s and low 90s. Dew points have also remained elevated across the south allowing the heat index to approach 100 to 105+ in some areas. A Heat Advisory will remain in effect for portions of NE NC through the evening as these areas are seeing heat indices of 105+. By tonight, temperatures are expected to drop into the upper 60s to low 70s. Patchy fog cannot also be ruled out across the MD Eastern Shore.

For Wednesday, drier air is expected to move in the area allowing dew points to be in the upper 60s to low 70s. Temperatures are likely to reach into the upper 80s to low 90s across the area. These temps mixed with the lower DP heat indices will likely be very close to the actual air temperature. The highest confidence in heat indices approaching the upper 90s to low 100s is across the SE where DP are expected to remain higher. With these DP slightly higher the better chance for showers and a thunderstorm would be across SE VA and NE NC. However, confidence in storm initiation is low and only a slight-chance (less than 25%) remains in the forecast.

KEY MESSAGE 2...Rain and storm chances increase Thurs-Sat with around seasonable temperatures.

An active pattern is looking more likely by the end of this week and into the weekend. A broad upper trough is expected to build over the Eastern United States, with multiple series of shortwaves from the Ohio Valley into the mid-Atlantic Thu-Sat. A strong cold front for this time of year will slowly approach the area starting Thursday. As of this update Thursday looks to be the best day for severe weather. This is due to the potential of the better shear overlapping with modest to strong instability. There also looks to be possibly multiple round with the first round being along a Lee trough and the second round being associated with the approaching cold front. With two rounds there is the potential with two different storm modes. The Lee trough there could potentially be a mix mode of discrete to semi-descreate cells that could pose supercellular characteristics as modest shear is likely to be in place. While along the stronger forcing cold front more of a cluster to line of storms is possible. The main concern remains the placement of the Lee trough and cold front. With collaborating with SPC decided to keep the marginal in place. In terms of the hydro threat, Thurs through Sat have the threat for localized Flash Flooding. PWs jump back AOA 2-2.3" and with them, the potential for more strong convection and locally heavy rainfall returns, likely coincident with the position of the stalled boundary. As mentioned earlier with the severe threat, there remains some uncertainty with these days and after collaborating with WPC a marginal remains in effect. However, if confidence in heavy rainfall increases especially over already saturated areas there could potentially be an upgrade in the risk. Model ensembles still generally agree that the main trough axis eventually shifts east late Sunday into early next week, driving the front through and briefly introducing a cooler, drier airmass across the mid- Atlantic before temperatures moderate again by the middle of next week.

AVIATION /19Z TUESDAY THROUGH SUNDAY/

As of 116 PM EDT Tuesday...

VFR conditions, isolated showers across southern VA, an MVFR CIG conditions across SBY have been noted at the start of the 18z TAF period. Lingering low stratus is expected to clear at SBY in the next hour or so, with VFR conditions thereafter through the end of the period. Only exception is with some scattered convection on the afternoon seabreeze is possible at the SE terminals and SBY that could lead to short- lived VSBY restrictions. With high enough confidence prob30s have been added. Some late night stratus/fog will once again be possible along the coast early Wednesday morning.

Outlook: Mainly dry/VFR conditions continue into midweek as weak high pressure returns. Potentially turning unsettled Thursday into the weekend ahead of a slow-moving frontal boundary that could bring additional rounds of showers and storms and brief sub-VFR conditions.

MARINE

As of 336 PM EDT Tuesday...

Key Messages:

- Generally benign marine conditions expected through the end of the week, outside of afternoon/evening thunderstorms.

A weak frontal boundary crossed most of the waters today, and is just to our south this afternoon. Winds are N-NE at ~10 kt with 2 ft seas and 1-2 ft waves. A few tstms are possible across the far SE VA and NE NC waters through this evening, which could result in brief, locally hazardous conditions (can't rule out a SMW or two for 34+ kt winds). Benign marine conditions are expected for the remainder of the week. Winds will veer back to the S/SE by Wed night, but will generally remain aob 10 kt. A weak frontal boundary approaches the waters on Thursday and likely stalls over the area on Friday. Even with the boundary nearby, not expecting much of an increase in wind speed although winds may become more variable. Seas will remain ~2 ft with 1-2 ft waves. The chance of storms decreases Wed, with a greater coverage of storms expected on Thursday/Friday. SMWs are possible with the stronger storms (especially on Thursday).

There remains a low risk of rip currents at all beaches over the next few days.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Heat Advisory until 8 PM EDT this evening for NCZ030>032. VA...None. MARINE...None.