textproduct: NWS Wilmington

WHAT HAS CHANGED

Surf zone forecast has been updated to include a strong longshore current for most beaches for Wednesday. Forecast lows for tonight were tweaked higher, with rain chances dropped below 20 percent for the coastal counties.

KEY MESSAGES

1) Deep tropical moisture in place this week will keep rain chances elevated, and maintain the potential for isolated flooding inland through this evening.

DISCUSSION

KEY MESSAGE 1...Deep tropical moisture in place this week will keep rain chances elevated, and maintain the potential for isolated flooding inland through this evening.

Not much pattern change through mid-week with southerly low- level flow promoting moisture transport into the Carolinas and upper-level ridging staying offshore. Forcing will be provided by the daily sea breeze, sfc heating, convective outflows, and weak upper-level divergence. Tough to pinpoint exactly where and when it will rain each day, but the expectation is for a typical summertime pattern with higher rain chances inland during the day, while higher over the coast and offshore overnight.

There continues to be a Marginal Risk of excessive rainfall and flash flooding over NW areas through this evening. Although the flooding risk is a bit lower than recent days and storms are currently moving at a fairly good pace, the combination of precipitable water exceeding 2", deep warm cloud layer (13k ft+) and some cells potentially training over the the same area will lead to the marginal flood risk.

Drier mid-level air works its way in later this week, especially Friday as sfc high pressure builds in from the north. There continues to be a lot of model disagreement over how far south a frontal boundary pushes through the Carolinas and where the northern edge of the precip will lie. Better mid-level energy will keep high rain chances (60-70%) for Saturday, with a low confidence forecast thereafter as guidance disagrees on whether sfc high pressure can build directly over the area (drier) or stay off to the north (wetter) Sunday into early next week.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Inland convection is wrapping up for the day, but there is still a low to moderate potential for MVFR visibility in showers at KLBT through 03z. Scattered marine cumulus moving onshore could bring brief MVFR ceilings to KILM, KCRE, and KMYR overnight, but this potential is too low to be included in the TAFs. We have somewhat higher confidence in inland low stratus developing late tonight affecting the KLBT and KFLO airports. Stratus should develop in the 07-08z timeframe and may continue as late as 13-14z before lifting into daytime cumulus.

The HREF ensemble paints a zone of scattered showers and thunderstorms Wednesday afternoon closer to the coast than we've seen the past couple of days. There's a mid-range probability that showers and t-storms could impact the coastal airports, and a low probability inland. Convection could develop as early as 16-17z.

Extended Forecast... The threat for late-night low stratus or fog will continue through much of this week at KFLO and KLBT. Scattered showers and thunderstorm may develop each day this week during the afternoons and evenings.

MARINE

Through Wednesday... A moderate breeze out of the SSW will veer to the SW early Wednesday, increasing slightly to a fresh breeze by the early afternoon. Seas remain at 2-4 ft over the coastal waters out 20 nm offshore, up to 4-5 ft over the offshore waters out 60 nm offshore. Outside of wind waves, look for the main SSE swell at 6-8 seconds, and a secondary ENE swell at 8-9 seconds.

Wednesday night through Sunday... High confidence in sub-SCA conditions continuing. Sfc high pressure remains locked in place offshore, with a frontal boundary dropping in from the north Thursday night. It is still unclear how far if at all the front drops through the area, but regardless winds should stay no higher than 10-20 kt with seas below criteria as well through Thursday night. Should the front clear the area to the south, a weak NE surge could lead to gusts up to 20-25 kt starting Friday. Confidence is not particularly high in regards to where the front ends up as well as where exactly sfc high pressure will lie this weekend into early next week, but this is mainly affecting uncertainty with the rainfall forecast.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement through Wednesday evening for NCZ106- 108. SC...Beach Hazards Statement through Wednesday evening for SCZ054- 056. MARINE...None.