textproduct: Wakefield

WHAT HAS CHANGED

A Heat Advisory has been issued for northeast North Carolina for most counties east of the Chowan River.

Convective and excessive rainfall outlooks remain similar.

KEY MESSAGES

1) Hotter summertime temperatures return today and Friday. Meanwhile, a more progressive upper level pattern develops today 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 far northern portions of the area today.

2) Near to slightly below average 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.

3) Hot temperatures potentially return by mid to late next week.

DISCUSSION

As of 355 AM EDT Thursday...

KEY MESSAGE 1...Hotter summertime temperatures return today and Friday. Meanwhile, a more progressive upper level pattern develops today 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 far northern portions of the area today.

GOES water vapor channels depict the axis of a subtropical ridge centered off the Southeast coast early this morning. Meanwhile, an upper trough is pushing across the Great Lakes, with a secondary wave over the upper Ohio Valley. At the surface high pressure is centered offshore with a weak trough inland. The low-level wind is light and generally out of the S to SE. Warm and humid with temperatures in the lower to mid 70s. Some areas of stratus were observed, which should linger early this morning, before scattering and lifting later this morning.

The subtropical ridge re-asserts itself today. 850mb temperatures return to 18-20C today NW-SW across the local area. This will support high temperatures ~90F across the N to the mid 90s SE. Dewpoints across NE NC east of the Chowan River will struggle to drop below the mid 70s during peak heating. Therefore, heat indices potentially reach 105-109F and a Heat Advisory has been issued for Chowan, Perquimans, Pasquotank, Camden, and Currituck Counties (excluding Outer Banks Currituck) from 11AM-7PM. Southside Hampton Roads will see heat indices in the lower 100s, but should largely remain below 105F as a slight SE component to the wind should help temperatures remain in the lower half of the 90s.

The mid/upper level flow becomes more progressive today and Friday. The 500mb flow increases to 30-35kt this afternoon ahead of a subtle shortwave trough (the feature currently over the upper Ohio Valley), with similar values Friday ahead of a more potent shortwave trough. With strengthening mid level flow and strong surface heating strong to locally severe tstms are possible each afternoon with the main threat being damaging wind gusts. The best potential for tstms today will primarily be N/NE of I-64 in closer proximity to the stronger ascent. Farther S, convection will likely be suppressed given warmer 850 to 700mb temperatures in closer proximity to the upper ridge. The question on Friday is coverage given more drier downslope flow. Additionally, the 00z/09 HREF and REFS have a decent signal for heavy rain later this afternoon and evening from the Northern Neck to SE MD (and points N). This is where there is a threat of localized flash flooding, with a much less risk farther S.

KEY MESSAGE 2...Near to slightly below average 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 pushes through the area. The main threat will be locally heavy rainfall with rich moisture and PW values 120- 140% of normal. A few stronger tstms are also possible. By the end of the weekend and into next week models hint at a drier pattern as high pressure returns to the area. Seasonally hot and humid Saturday, with high temperatures in the mid 80s to lower 90s. High temperatures trend down into the 80s Sunday and Monday (with some guidance suggesting lower to mid 80s), before a warming trend commences Tuesday.

KEY MESSAGE 3...Hot temperatures potentially return by mid to late next week.

Global ensemble guidance depicts an upper ridge building over the upper Midwest by early next week and pivoting into the Mid- Atlantic by mid to late next week. This will allow for a return to hot temperatures will highs potentially well into the 90s by mid to late next week. Ensemble guidance also shows PW values near to slightly below normal, so mainly dry conditions should be favored much of next week.

AVIATION /07Z THURSDAY THROUGH MONDAY/

As of 205 AM EDT Thursday...

Areas of stratus were developing across the region as of 06z. MVFR cigs were observed at RIC and ECG with VFR conditions elsewhere. ORF and PHF are expected to drop to MVFR through 08z, with RIC falling to IFR ~08z. SBY should primarily remain VFR with brief MVFR possible early in the morning. A few showers and perhaps a tstm could move across the region early this morning. However, confidence of directly impacting any given terminal is very low. Conditions gradually improve later this morning with VFR conditions prevailing after ~15z. There is a chc of showers and tstms later this aftn and evening. The best probability is a RIC and SBY where PROB30 groups have been added. Any tstms could produce some brief strong wind gusts. Any showers/tstms move offshore later this evening with VFR condition prevailing overnight. A light SE wind early this morning will become SSW 5-10kt today, and then light out of the SW tonight.

Outlook: Chances of aftn/evening showers/tstms by Friday is generally ~30% at RIC and 30-50% at SBY, with 20% or less elsewhere, then 60-70% by Saturday. Trending drier and VFR Sunday into Monday.

MARINE

As of 355 AM EDT Thursday...

Key Messages:

- Sub-SCA marine conditions are expected through the end of the week.

- There is a risk of localized higher winds and waves from thunderstorms later this afternoon and evening and again on Friday.

- Elevated onshore flow may develop later Sunday into Monday with Small Craft Advisories possible.

Benign marine conditions prevail through the forecast period. Winds this morning are out of the S-SE and generally 5-10 kt. A very weak front will cross the waters this evening/early tonight, with a wind shift to the W-SW. The main focus with this feature will instead be the potential for strong to severe storms capable of producing localized pockets of higher winds and waves. The prevailing flow will be out of the S Friday and less than 10 kt, though additional storms are possible. A more substantial front is forecast to drop southward Saturday with northerly sub-SCA winds developing in its wake. There is then an emerging signal for weak low pressure to develop just S of the local waters Monday, beneath a high pressure system to our N. This could lead to a prolonged period of northeasterly onshore flow from later Sunday through at least Monday. At this time, will forecast 15-20 kt w/ gusts to 25 kt for the lower bay and coastal waters. Seas would also build to at least 4-6 ft (3-4 ft waves lower bay) given this wind speed and direction combination. Overall, the current forecast would necessitate Small Craft Advisories, but uncertainty remains at this state so will monitor over the coming days.

EQUIPMENT

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

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for NCZ015>017-031-032. VA...None. MARINE...None.