textproduct: Wakefield

WHAT HAS CHANGED

- Severe Thunderstorm Watch in effect through 11 PM EDT for portions of south-central, central, and east-central Virginia.

- A Coastal Flood Statement has been issued for the Bayside of the Maryland eastern shore for the the high tide cycle tonight.

KEY MESSAGES

1) Severe Thunderstorm Watch in effect through 11 PM EDT for portions of south-central, central, and east-central Virginia. There is a Slight Risk (2 out of 5) for severe thunderstorms across all zones through this evening (including zones not in the Watch).

2) A cooler, drier pattern takes hold early this week. A return to warmer and more humid conditions Wed-Thu and the potential for strong to severe thunderstorms later Thursday.

DISCUSSION

As of 420 PM EDT Sunday...

KEY MESSAGE 1...Severe Thunderstorm Watch in effect through 11 PM EDT for portions of south-central, central, and east-central Virginia. There is a Slight Risk (2 out of 5) for severe thunderstorms across all zones through this evening (including zones not in the Watch).

Updated to add SVR Tstm Watch through 11 PM. Latest analysis indicates W-SW flow aloft across the FA this aftn with an upper trough approaching the central/southern Appalachians. At the surface, a cold front is still well off to our NW from western NY to the OH Valley. A weak sfc warm front lifted north through the CWA earlier this morning, allowing dew pts to surge into the low-mid 70s across SE VA/NE NC, though they are now mixing out into the upper 60s to lower 70s area- wide. Thus far, widely scattered showers and tstms have started across south central VA and into eastern/central NC, but have been struggling to intensify despite ample thermodynamic profiles- ML CAPE 1500-3000 J/Kg, DCAPE>1000 J/Kg, and 0-3 km lapse rates ~8.5C. What is limited is likely that weak riding is still in place in the H7-H5 layer. After ~5 PM, height falls are forecast to push into the piedmont as the trough aloft moves in from the west, shifting towards the coast through ~8PM. This will lead to increasing deep layer shear (to 25-35 kt), though mid level lapse rates are still very marginal at best 5.5C to ~6C/Km. Latest SPC discussion mentions an 80% chc for a SVR Watch as this occurs, so continue to monitor forecast updates. Given all of this, there will be threat for strong to severe storms, mainly from about 5PM -9PM (potentially lingering a few hrs longer near the coast). 18Z soundings from LWX/RNK show a well mixed inverted V profile sounding, with straight line damaging winds gusts as the main severe mode. A brief spin up cannot be completely ruled out, especially across NE portions of the area mainly due to localized land/marine interactions. As for hail, expect the potential for small hail, but large hail will likely be hard to come by due to marginal mid-level lapse rates. Finally, storms will be moving rather quickly so only isolated instances of flash flooding are expected over urban areas. The cold front moves through a majority of the area between about 2 Am and 5 AM, night bringing drier air and ending the threat for any severe weather. However, in typical fashion for the summer months, the front likely stalls near or just south of the local area, with a few showers possible in NE NC into early Mon aftn.

KEY MESSAGE 2...A cooler, drier pattern takes hold early this week. A return to warmer and more humid conditions and the potential for strong to severe thunderstorms Thursday.

Cooler conditions are expected through at least the first half of next week as an upper trough develops over the eastern half of the US. In addition, the front from today/tonight lingers near or just south of the area. The forecast has remainder similar for Monday with only a small chance for a shower or storm across far S/SE portions the area, the majority of the area will remain dry. Much drier air (dewpoints in the 50s to lower 60s), near to slightly below average temperatures (low to mid 80s), and partly sunny skies should make for pleasant and comfortable day. Clouds and rain chances expand back a bit further N/NW on Tuesday as the front to the south begins to lift north. The best rain chances (scattered showers/storms) on Tuesday will mainly be near/along the Albemarle Sound in NC with lower chances off to the N/NW. Temperatures stay in the low-mid 80s (upper 70s/around 80 closer to the coast) on Tuesday with the increase in cloud cover, precipitation chances, and onshore flow. Warmer and more humid conditions return for the mid to later portions of the week as the trough begins to break down and a warm front lifts through the area. The Thursday-Friday timeframe likely becomes more active preciptation-wise as another front approaches and crosses the area from the NW. We are also watching for another severe weather potential, with SPC highlighting northern portions of the area in a day 5 15% severe weather outlook. In addition, temperatures may approach Heat Advisory criteria for portions of the area on Thursday.

AVIATION /20Z SUNDAY THROUGH FRIDAY/

As of 200 PM EDT Sunday...

VFR conditions prevail with mainly SCT cu and S-SW winds around 10 kt with gusts to 15-20 kt across the main terminals. However, starting to see widely scattered showers and a few tstms off to the W/SW of the region (and also along the Carolina coast). Precise timing and coverage remains uncertain, but the greatest chances for flight restrictions appear to be from around 22Z-03Z (latest at SBY). Have included TEMPO groups for TSRA at all terminals, primarily from 22Z-02Z, except 00-04Z at SBY. Some storms may be severe with damaging wind gusts being the main threat, but for the TAFs have limited to gusts to 30-35 kt for now. Storms taper to rain showers later in the evening/overnight before ending. MVFR CIGs potentially develop after midnight, mainly closer to the coast. Winds are forecast to shift from SW to the N-NW between 07-10Z at RIC/SBY, and a few hrs later for SE VA/NE NC. Gusts to ~20 kt are likely through Monday morning/early aftn near the coast, and a few showers could redevelop in NC and affect ECG through 18Z/Mon (though chances are 30% or less).

Outlook: Any lingering SHRA are expected to be south of the region later Monday, with VFR/dry conditions to prevail Mon night. Becoming more unsettled on Tuesday, with the potential for a few showers, mainly for SE VA/NE NC, and then all areas late Tue night into early Wed AM. Primarily dry/VFR conditions return for Wednesday through most of Thursday, with showers/tstms possible late Thu/early Friday.

MARINE

As of 300 PM EDT Sunday...

Key Message:

- Small Craft Advisories in effect for the Ches. Bay this evening through tomorrow morning for SE winds of 15-20kt, becoming NW early tomorrow.

A warm front is currently draped across the northern local waters this afternoon, with winds generally the SE-SW. Winds have increased to 10-15 kts this afternoon, and gusts around 15 kts, with a few marine observation sites already seeing gusts to 15-20 kts. The seabreeze influence also has a few areas in the Bay seeing more easterly winds. Waves in the Bay are generally 1 ft or less, with seas in the coastal waters seeing between 2-3 ft.

A cold front is approaching the area this afternoon and winds will likely continue to ramp up some over the next few hours. SCAs are in effect for the Bay, though winds will remain more marginal with this initial surge ahead of the front. Winds and seas will fall slightly short of SCA criteria in the coastal waters, though there may be a few gusts to 25 kts across the nearshore coastal waters this afternoon/evening. Thunderstorms will start to develop this afternoon and evening along the front, bringing the potential for severe wind gusts (50 kt+), isolated waterspouts, and small hail. This storm threat will be handled with Special Marine Warnings as needed. In the wake of the front on Monday morning, winds will shift to the northwest and surge to 15-20 kts. While there will likely be a slight decrease in winds tonight, the SCA for the Bay extends through Monday morning to cover this secondary surge. High pressure will build in behind the front, allowing winds to diminish pretty quickly by Monday afternoon. Marine conditions will remain benign through mid week as flow of 5-10 kt becomes onshore on Tuesday, then shifts to the south on Wednesday. Another front will approach the area by late week and could bring elevated winds to the coastal waters on Thursday and Friday.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 11 AM EDT Monday for ANZ630>632-634.