textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for 18Z forecasts. Key messages largely unchanged.

KEY MESSAGES

1) Shower and thunderstorm chances will shift from the SC Lowcountry today back into northeastern South Carolina and southeastern North Carolina Sunday into Monday.

2) Drier weather is expected from Tuesday through Thursday, but with increasing temperatures and potential for the heat index to exceed 105 degrees.

DISCUSSION

KEY MESSAGE 1...Shower and thunderstorm chances will shift from the SC Lowcountry today back into northeastern South Carolina and southeastern North Carolina Sunday into Monday.

A slug of dry mid level air associated with the Bermuda ridge offshore has lead to lower coverage of showers and storms today.

The center of the Bermuda ridge should sink south Sunday into Monday, allowing veering mid level wind directions and increasing Gulf moisture across the area. Precipitable water values should climb back toward 2.0 inches by late Sunday and should rise even further on Monday. This should set the stage for increasing coverage of showers and thunderstorms, especially Monday.

KEY MESSAGE 2...Drier weather is expected from Tuesday through Thursday, but with increasing temperatures and potential for the heat index to exceed 105 degrees.

The mid and upper level ridge will begin to retrograde westward across Florida and into the eastern Gulf by the middle of next week. Westerly downsloping flow over the southern Appalachians should push our 850 mb temps above +20C each day beginning Tuesday. This should equate to highs in the 93-97 degree range. Add in seasonably high dewpoints well into the 70s and it's possible heat indices will exceed 105 degrees beginning Tuesday. A Heat Advisory may be needed each day.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Overall, expect VFR conditions through much of the period with light winds outside sea breeze affected areas. There is potential for MVFR/IFR fog tonight, mainly inland. For now, forecast shows 5 miles at FLO/LBT but vsbys late tonight could end up being lower. Aft 12Z, showers could affect SC coastal terminals.

Extended Forecast...Increasing moisture should fuel scattered showers and thunderstorms Sunday afternoon, with an even larger coverage of storms expected Monday. Hotter weather is expected for the middle of next week with isolated showers and thunderstorms still possible. Late night/early morning low ceilings are possible day, especially inland, affecting the KFLO and KLBT airports.

MARINE

Bermuda high pressure offshore should remain the dominant weather maker for us over the next five days. The center of the high is currently between Bermuda and Cape Fear, close enough to limit today's coverage of showers and thunderstorms for areas north of Myrtle Beach. The high should sink south next week, leading to winds veering more westerly and increasing in speed. We also should experience a larger number of showers and thunderstorms Sunday and especially Monday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...High Risk for Rip Currents until 8 PM EDT this evening for NCZ106- 108. SC...High Risk for Rip Currents until 8 PM EDT this evening for SCZ054- 056. MARINE...None.