textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion has been updated for 12Z TAFs.

KEY MESSAGES

1) Deep tropical moisture will maintain the potential for excessive rainfall Wednesday and Thursday.

DISCUSSION

KEY MESSAGE 1...Deep tropical moisture will maintain the potential for excessive rainfall Wednesday and Thursday.

The western Atlantic ridge will weaken today, deflating through the end of the week. As upper level flow veers toward the west, moisture advection across the southeastern US and the coastal Carolinas will shift toward the south and east. Gulf moisture will not be advected as efficiently as previous days, but the air mass will more than sufficient for afternoon showers and storms. The slight change in upper level winds will shift rain chances closer to the coast this afternoon. REFS/HREF favor convective initiation near US-701 after noon. Storms in the vicinity of a near-coast sea breeze may lead to a progressive interaction of outflows, expanding to scattered or widespread coverage by mid to late afternoon. Inland areas may still see periodic convection during the afternoon, but early initiation farther east will produce debris clouds and limit heating potential. PoPs here are slightly lower then eastern counterparts, but confidence is also lower.

For much of Thu the air mass remains unchanged with an abundance of deep moisture, although precipitable water is down a bit compared to earlier in the week. Initially forcing is weak with limited low level convergence and pockets of surface based instability under flow aloft that is weakly divergent bordering on being convergent. The lackluster environment will keep storm coverage limited into Thu afternoon, likely scattered sea breeze action, until a cold front moves in from the north. The front has the potential to kick off more widespread showers and thunderstorms given the environment it is moving into. Exact timing of the front is still in question, but nearly all of the guidance insists the front will push south of the area sometime Thu night into Fri. Heavy rain will be possible in any convection that develops along the front with potential for significant rainfall amounts. However, flooding is not a concern at the moment.

AVIATION /10Z WEDNESDAY THROUGH SUNDAY/

Low clouds (MVFR) will quickly lift to VFR this morning. The main impact today will be the development of convection during the early afternoon. Steering flow could keep showers and storms closer to the coast than previous days, but inland terminals may see some storms later in the afternoon. Rain could be prolonged, ending by this evening. Low clouds are likely to return tonight.

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. An approaching cold front late this week will linger through the weekend. Showers and storms along the front will bring prolonged restrictions.

MARINE

Through Tonight... Bermuda High begins to degrade today through the remainder of the week. Winds more southwesterly today and slightly stronger than previous days. SSW winds around 15 knots could gust up to 20-25 knots near the coastal sea breeze; gusts up to 20 knots expected elsewhere. Synoptic gradient increases tonight as winds also turn SW. Gusts up to 30 knots will be possible in the offshore waters tonight into early Thursday. Winds and seas higher in thunderstorms developing late tonight into early Thursday as well.

Thursday night through Sunday... Southwest flow around west side of retreating surface high will be a solid 15 kt with potential for 20 kt out near 60 nm ahead of a cold front moving in from the north. The front will push south across the waters Thu night into Fri with winds shifting from southwest to northeast. Northerly surge Thu night into Fri will briefly increase winds and seas, but conditions will remain below SCA thresholds. The front stalls in the area, likely just to the south, Fri before returning back north Sat. The result will be variable winds, but with speeds around 10 kt as the gradient remains weak. A second front, late in the week, pushes south, setting up another northerly surge for Sun.

ILM WATCHES/WARNINGS/ADVISORIES

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