textproduct: NWS Wilmington

WHAT HAS CHANGED

Coastal Flood Advisories issued for Inland New Hanover, Coastal Horry and Coastal Georgetown counties. Updated 12Z TAF discussion.

KEY MESSAGES

1) Inland portions of the eastern Carolinas should see their longest heat wave of the year so far with 90 degree heat expected to continue through Thursday.

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

DISCUSSION

KEY MESSAGE 1...Inland portions of the eastern Carolinas should see their longest heat wave of the year so far with 90 degree heat expected to continue through Thursday.

A 590 dam upper ridge centered near the North Carolina coast is responsible for the sustained period of hot inland temperatures which should last through Thursday. Sinking air below the upper ridge should create a deep warm, dry layer extending down through 700 and 850 mb. Models have maintained their 850 mb temp forecasts of +17C 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 more than 25 miles inland.

Our forecast is for an additional four days (Monday through Thursday) of 90+ degree heat inland. Assuming that Florence and Lumberton highs touch 90 degrees this afternoon, this 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 upper ridge will become more narrow with time as an upper low strengthens across the northern Bahamas Tuesday into Wednesday. This feature looks a lot like an early season TUTT low, but any enhanced convection or other sensible weather impacts should remain far to our south. The arrival of a surface cold front Thursday afternoon should end this heat wave with temperatures returning toward normal for the coming weekend.

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

Dry weather will come to an end as early as Thursday morning. 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 may lift north of the area into the weekend but the warm, humid air mass will continue to support rain chances through the end of the period.

Little change in the difference between the NBM and other guidance with forecast POPs reflecting widespread showers/storms that I think will be more scattered near the boundaries. Calling rainfall totals this far out is tough but it does look like there's a signal for higher totals, mainly for the coastal areas, Friday into Saturday with the possibility of a passing low shoving more moisture onshore. Low confidence on the placement of this feature at this time.

AVIATION /09Z MONDAY THROUGH FRIDAY/

Transient creek/swamp fog/stratus has made an appearance at CRE/ILM and will linger through 12Z or so before mixing out. VFR at all sites today.

Sea breeze will again develop and push inland around midday with gusts 15-20 kt at the coast arriving at inland terminals mid to late afternoon.

MVFR/IFR fog potential tonight with best chances once again along the coast. Inland sites will have slightly higher chances Tue morning compared to this morning due to increased boundary layer moisture.

Extended Forecast...VFR through Wednesday though morning fog potential increases each day. An approaching front could bring restrictions in scattered showers and storms Thursday and Friday.

MARINE

Through Tonight...South to southeast flow across the waters continues today and tonight with Bermuda High in place. Sea breeze development by midday will enhance winds near shore with potential for gusts 15-20 kt within a few miles of land. Otherwise winds will be around 10 kt with minimal gusts. Combination of a weak southeast swell and weak southerly wind wave will keep seas 2-3 ft.

Tuesday through Saturday...Bermuda high pressure remains in control through Thursday with onshore flow enhanced in the afternoons by the daily sea breeze. A could front will approach Thursday night into Friday but doesn't look to clear the coastal waters with SE winds prevailing. Showers and storms are possible Thursday onwards.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT Tuesday for NCZ107. SC...Coastal Flood Advisory from 8 PM to 11 PM EDT this evening for SCZ054-056. MARINE...None.