textproduct: NWS Wilmington

WHAT HAS CHANGED

Updated 12Z TAF discussion.

KEY MESSAGES

1) Temperatures well above normal, particularly for areas west of I-95, will continue through Thursday.

2) Rain chances should increase, especially inland, beginning Thursday as a front temporarily stalls in the Carolinas.

DISCUSSION

KEY MESSAGE 1...Temperatures well above normal, particularly for areas west of I-95, will continue through Thursday.

An upper high will shift into the Atlantic and leave an axis of higher heights from the Gulf into the central Atlantic, and this is responsible for the sustained period of hot inland temperatures, which should last through Thursday. Sinking air below the upper ridge will create a deep warm, dry layer in the middle troposphere, supporting abnormally warm surface temperatures. Models have maintained their 850 mb temp forecasts of +16C to 18C (at or above the 90th percentile climatological values for this time of year), which increases confidence in our forecast of 90+ degree heat continuing through Thursday for locations away from the daily cooling influences of the sea breeze.

Our forecast is for 90+ degree heat inland through Thursday. Since Florence and Lumberton highs reached 90 degrees on Sunday, a five day streak would eclipse this year's earlier streak of four days of 90 degree temps recorded from April 15-18 in both Florence and Lumberton. Coastal portions of the Carolinas should remain significantly cooler than inland due to sustained south winds dragging air across nearshore water still near 70 degrees.

The timing of the cold front looks to have slowed to Thursday night, stalling in the area Friday before lifting north once more for the weekend.

KEY MESSAGE 2...Rain chances should increase, especially inland, beginning Thursday as a front temporarily stalls in the Carolinas.

Dry weather will come to an end as a front shifts in from the north on Thursday. There's reasonable uncertainty on placement of highest POPs day to day as we deal with a stalled front in or near the area and the daily sea breeze. The front should lift north of the area into the weekend but the warm, humid air mass will continue to support at least daily pop-up shower and storm chances through the end of the period.

POPs Thursday through the weekend have been lowered to reflect trends from non-NBM guidance. For now, highest precip chances will be Friday with the frontal passage, but lack of any PVA aloft will limit widespread coverage.

AVIATION /10Z TUESDAY THROUGH SATURDAY/

Any MVFR/IFR from fog and stratus in the area will dissipate by 12Z leaving VFR at all sites well into the evening. Fog will again be a concern and guidance is showing a modest increase in moisture in the lowest levels. The moisture remains shallow, although boundary layer winds will decrease slightly. This all suggests fog will be more widespread and have more staying power than what has been seen this morning.

Once again the sea breeze will develop and push well inland. Coastal terminals will see gusts 15-20 kt by midday. Sea breeze will reach FLO/LBT between 22Z and 00Z.

Extended Forecast...MVFR/IFR fog/ceilings are possible Wednesday through Saturday mornings, generally in the 08z-12z timeframe. Confidence is moderate. Potential for daytime restrictions Friday and Saturday due to convection.

MARINE

Through Tonight...Pattern remains unchanged with Bermuda High resulting in southerly flow across the waters. Midday sea breeze will enhance wind speeds close to shore with potential for 10-15 kt gusting to 20 kt. However, the majority of the waters will see wind speeds closer to 10 kt with limited gusts. A southeast swell 2-3 ft will be the only significant wave through tonight.

Wednesday through Sunday... Southerly flow will remain in control through the period with increasing shower/storm chances Thursday onwards. A front will approach the area Friday but for now is not expected to clear the waters. Should it, winds could turn E to even NE during Friday before the front lifts north again later Friday night. Otherwise, winds speeds will be enhanced each afternoon close to the coast to ~15 kts. Seas within 20nmi will be 2-3 ft and 3-4 ft beyond. The primary swell will be SE at 8-9 seconds.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.