textproduct: NWS Wilmington

WHAT HAS CHANGED

High rip current risk now in effect for New Hanover and Pender county beaches today.

Confidence continues to increase that a tropical air mass will provide widespread rain chances through much of this upcoming week.

KEY MESSAGES

1) Scattered showers and storms possible each day over the next 5 days, bringing welcomed rainfall.

DISCUSSION

KEY MESSAGE 1...Scattered Showers and Storms Possible Each Day Over the Next Week, Bringing Welcomed Rainfall.

Atlantic and Gulf moisture to combine across Northeast SC and Southeast NC during the next 5 days. Will have a stationary frontal boundary draped across the area today that will slowly lift north of the local area tonight into Mon. Onshore movement of nocturnal showers will be ongoing at the start of this early Sun. Once the days heating commences, and the sea breeze takes shape and pushes inland, look for thunderstorm activity to develop with increasing coverage thru the aftn into the evening. With PWs across the area progged at 1.75 to 2.00 inches, expect potential 24 hr rainfall amounts, ending Mon 8am, to generally range from 1/2 to 1 inch except slightly lower amounts across coastal SC. And of course, expect locally hier amounts from any slow moving thunderstorm activity that could potentially train across the region.

Bermuda high and upper ridge over the southwestern Atlantic will advect a deep plume of Gulf moisture northward across the southeastern US and the Carolinas through mid week. Deterministic models suggest that PWAT values near 2 inches are possible each day which would be near the max for late May, based on CHS sounding climatology. Each day, activity is likely to initiate along the sea breeze and progress inland along generated outflows and weak synoptic lift. Some days may see more or less activity than others, but this will come into more detail as the mesoscale environment is established with 12-24 hours of convective initiation. After today's activity, rainfall totals appear promising for some drought relief. While we will not have the benefit of organized isentropic lift across the area through much of the week, showers and thunderstorms will be slow-moving and widespread. This should provide consistent opportunity for a few heavy downpours. Global probabilistic guidance (which will not resolve a scale small enough for some of the heaviest rain) advertises rainfall totals of up to 2 inches west of I-95 at the 25th percentile through Friday afternoon. Coastal areas are above 1 inch at the 25th percentile through Friday afternoon. While this pattern is not a drought buster, it certainly looks like the most favorable pattern we've seen in months. A drought "denter," perhaps.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

A frontal boundary stalled over inland areas and the development and inland progressing late morning thru early evening sea breeze will combine with the high moisture content atm, with PWs generally in the 1.75 to 2.00 inches range, to produce scattered to widespread showers and thunderstorms across the area later this morning into this evening. Initially, onshore movement of pcpn to dominate followed by tstm activity across land areas due to the days insolation combined with the mentioned boundaries. Expect periodic MVFR and possibly IFR across all terminals during the next 24 hrs. Will mainly cover this pcpn potential with PROB30 groups. During the 1st 6 hrs, the inland terminals "on the other side of the stalled front" could observe residual IFR/LIFR stratus and/or fog. Winds generally NE-E west thru north of the frontal boundary and SE-S east thru south of the boundary. Winds will become southerly thruout once the front lifts north of the area. Winds speeds generally 5 kt or less this morning, increasing to around 10 kt this afternoon thru this evening.

Extended Forecast... VFR outside the daily periodic MVFR/IFR ceilings and/or vsby from shower and thunderstorm activity. In addition, look for MVFR/IFR from low stratus and/or fog during the daily pre-dawn hrs.

MARINE

Through Tonight... Sfc ridging from the highs center well offshore from the SE States Coast, will continue to influence the winds across the local coastal and offshore waters thru this period. The wedge across the inland Carolinas from the north will break down during this period. The overall relaxed to modest sfc pg will produce a SSE-SSW wind direction at 10-15 kt speeds across the coastal waters, and at 15-20 kt g25 kt for the adjacent offshore waters thruout this period. Seas will run 2 to 4 ft coastal waters, 3 to 5 ft adjacent offshore waters. The SE Swell at 7 to 9 second periods will dominate the seas spectrum with short period wind waves on top. Isolated to scattered convection will occupy the local waters with activity more widespread across the Gulf Stream moving across the offshore waters.

Monday through Thursday... South to south-southwest flow continues through much of this week as the western periphery of Bermuda high pressure holds steady. Seas generally 2-4 ft over the coastal waters, 4-5 ft over the offshore waters. Outside of wind waves, 3-4 foot SE swell at 6-8 seconds remains consistent through Thursday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...High Risk for Rip Currents until 8 PM EDT this evening for NCZ106- 108. SC...None. MARINE...None.