textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for 12Z TAFs.

Some changes made to weekend forecast for timing, however the potential for rainfall Saturday and Sunday remains high.

KEY MESSAGES

1) Widespread showers and a few thunderstorms are expected this weekend ahead of an approaching cold front.

DISCUSSION

KEY MESSAGE 1...Widespread showers and a few thunderstorms are expected this weekend ahead of an approaching cold front.

Plume of tropical moisture, evident on water vapor imagery and in latest CHS/JAX RAOBs, will continue to spread over the region today. Latest CHS RAOB showing precipitable water at 2.1" with JAX at 2.5" (both of which are more or less the daily max). This tropical air mass will help set the stage for an unsettled weekend, although questions still remain concerning just how unsettled. A front sagging south tries to move into the area later today, with pre-frontal convergence helping generate showers and thunderstorms along the northern portion of the forecast area. A secondary area of convection may develop along a weak sea breeze pinned along the SC coast. However, activity here would be weaker with less coverage. There is a bit of mid- level support from the remains of a weak shortwave and a weak 200mb jet passing today. Neither feature is very impressive, but with the air mass and the presence of weak low level convergence anticipate seeing some convection develop.

The location of the front will determine rain chances through the remainder of the weekend. Would not be shocked if the front ends up laying southwest to northeast tonight, near the I-95 corridor then eventually moving to the coast during Sun as a more typical cold front vs a backdoor front (although the backdoor front wavering across the area is still a possibility). Either scenario will lead to unsettled conditions tonight through Sun night, although if the front ends up inland, areas east of the front would see more of a convective rainfall distribution while areas closer to the front or to the west of it see more of an even distribution of rainfall. Given the very high precipitable water values, deep warm cloud layer and slow moving storms, with potential for training, cannot rule out some flood products being issues at some point this weekend, however the antecedent conditions should keep any flooding impacts limited.

A mid-level trough helps move the front to the coast later Sun or Sun night with the front pushing offshore. Although the trough axis passes Sun night into Mon, kicking the front offshore, deep dry air is slow to arrive, and much of Mon could be unsettled.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Convection increases across the area today with deep tropical moisture in place ahead of an approaching front. Although the sea breeze will be weak and pinned to the coast, there is at least some indication of weak convergence along the coast, which may be what helps generate weaker convection across coastal SC this afternoon. Farther north and inland the front's influence will increase, with pre-frontal convergence generating a few storms which then propagate via outflow. While the air mass is quite juicy, forcing remains limited and weak. So do not expect widespread coverage initially, hence continuing PROB30 in the TAFs through the afternoon. Do still expect each terminal will experience ceiling and visibility restrictions today, just of relatively short duration. However, tonight, the potential for MVFR/IFR increases with abundant moisture and light to calm winds in place.

Extended Outlook...Potential for MVFR/IFR Sunday, increasing Sunday night with IFR becoming more likely. IFR may linger for much of Monday before VFR returns Monday night.

MARINE

Light southerly flow continues today and may continue uninterrupted through Sun. There are now some indications the front that had been expected to sag south, will remain north and west of the waters, with the weak gradient keeping speeds 10 kt or less. The front now appears to move offshore Sun night with west and then northwest winds setting up. No real strong northerly push right behind the front with north to northeast flow not increasing until Mon night or Tue. Still expect to see headline conditions develop once the surge arrives, likely Mon night. Anticipate seeing a couple days worth of headlines.

ILM WATCHES/WARNINGS/ADVISORIES

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