textproduct: Wakefield

WHAT HAS CHANGED

Updated 00z Aviation discussion

Urban and flood prone areas could see localized flash flooding Friday from scattered showers/storms.

Confidence is increasing with respect to hot temperatures during the early to middle portion of next week.

KEY MESSAGES

1) Unsettled conditions return today through Saturday with daily chances for showers and thunderstorms.

2) Hot conditions prevail during the early to middle portion of next week.

DISCUSSION

As of 1000 PM EDT Thursday...

KEY MESSAGE 1...Unsettled conditions return tonight through Saturday with daily chances for showers and thunderstorms.

Latest wx analysis shows an upper level trough over the Great Lakes region with a ridge over western Atlantic, causing SW flow aloft and a surface stationary boundary draped near/ just N of the VA/NC state border. Slow-moving scattered showers and storms developed mainly just to our northwest along a pre-frontal trough. Given very weak steering flow, these storms have produced some locally heavy rainfall just to our W-NW of the US-15 corridor. Latest mesoanalysis showing a weak covergence boundary developing just NW of RIC at this hour, and the past few runs of CAMs have shown some scattered storms pushing across our NW tier of counties through the early overnight hours (approximately Cumberland to Ashland to Tappahannock), and have nudged PoPs into the 40-60% range in this area, highest western sections. Minimal if any severe threat left over, but frequent lightning and heavy rainfall are possible. Farther south, some very low PoPs have been maintained across far SE counties along the Albemarle Sound.

The boundary drops SE tonight and settles into interior SE VA and the Carolina Coastal Plain by Friday, but remains rather diffuse. There is a strengthening jet core over New England, but there remains some uncertainty as to how well the RRQ of this feature interacts with the surface boundary. The 12z HREF continues to a decent signal for locally heavy rain from showers/tstms with a contour of a 30% chc of 3"/3hr across eastern/SE VA and NE NC to the Richmond/Tri-City metro areas. WPC has expanded the Slight Risk of Excessive Rainfall slightly north, now covering the southern half of the FA. Locally heavy rainfall is the main threat tomorrow, but a few stronger storms are possible with damaging winds possible, with 20-25 kt of SW flow aloft. SPC maintains a Marginal Risk of severe storms for the entire area Friday. Showers/storms look to be scattered to widespread based on the latest guidance. PoPs are now 50-70% for a large portion of the area after 2 PM into the evening. Locally heavy rainfall will be possible in any showers/tstms. Drier conditions arrive by Sunday with only low PoPs over interior SE VA/interior NE NC.

Seasonally hot and humid today through Saturday with high temperatures primarily in the mid to upper 80s, and nudging up to the upper 80s/around 90F (mid 80s at the coast) Sunday.

KEY MESSAGE 2...Hot conditions prevail during the early to middle portion of next week.

Hot conditions return early-mid next week as a 1.5-2.0 st dev 500mb ridge builds from the Central Plains to the Southeast. NBM high temperatures Monday through Wednesday are primarily in the lower to mid 90s. However, 850mb temperatures are primarily 19-21C in the 12 z/27 EPS/GEFS, with similar values in the deterministic 00z ECMWF. This along with 1000-850mb thickness schemes support highs in the mid to upper 90s. The 12z GFS continues to be even hotter, but remains an outlier. If the hotter temperatures are realized that will mean deeper mixing, which should allow dewpoints to drop into the upper 60s/around 70F during peak heating. Regardless, this would support heat indices into the lower 100s. A developing negative height anomaly near 40N/50W may cause the eastern portion of the ridge break down/retrograde later next week. However, Thursday likely remains quite hot as well. Mainly dry with PoPs near to below climo Monday through Wednesday. Chances of showers/tstms may not return until Thursday once NW mid-level flow increases as the eastern flank of the ridge breaks down.

AVIATION /01Z FRIDAY THROUGH TUESDAY/

As of 805 PM EDT Thursday...

VFR conditions prevail to begin the 00z/28 TAF period. Isolated showers/storms have developed NW of the KRIC terminal early this evening, but confidence is still not high enough to include mention at any of the terminals. Winds remain light and variable overnight into Friday morning. Patchy MVFR CIGS are possible late tonight after 08-10z through mid-morning Friday along the coast, with some patchy fog/low stratus possible at RIC toward sunrise Friday morning.

Outlook: A higher chance of showers/tstms is likely Friday afternoon and evening, with lingering showers/tstms Saturday. Brief sub- VFR conditions possible in any showers/tstms. Trending drier and mainly VFR by Sunday and Monday.

MARINE

As of 155 PM EDT Thursday...

Key Messages:

- Generally benign conditions today and into the weekend with a weak front briefly moving into the region early Saturday.

- Widely scattered showers and storms expected this afternoon and evening with greater storm coverage expected Friday.

Afternoon analysis shows a weak warm front lifting northward this afternoon with S and SE winds around 10 kt. Waves are 1-2 ft with seas 2-3 ft offshore. SE winds increase modestly into the 10-15 kt range and become S into the evening. A few gusts approach 20 kt this evening and tonight before winds transition to SSW or SW and decrease to 5-10 kt by sunrise Friday. Generally benign marine conditions are expected on Friday, however do expect higher coverage of showers and storms in the afternoon and evening hours. Strong winds and locally enhanced waves/seas can be expected in and around thunderstorms cores tomorrow. A weak cold front drops south across the local waters by Saturday morning but with little in the way of cold or dry advection, not expecting N/NW winds to exceed 10 kt. Waves will mainly hold in the 1-2 ft range with seas 2-3 ft through the weekend.

There is a moderate rip current risk today for the northern beaches due to nearshore waves building to 3 ft with a 8-9 second dominant period. Expect low rip risks to return for all beaches into the weekend.

AKQ WATCHES/WARNINGS/ADVISORIES

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