textproduct: Columbia

WHAT HAS CHANGED

Minimal change to Key Messages. Aviation discussion updated for 18Z TAF issuance.

KEY MESSAGES

- 1. Above normal temperatures with increasing chances for showers and storms late week into the weekend.

DISCUSSION

KEY MESSAGE 1: Above normal temperatures with increasing chances for showers and storms late week into the weekend.

Little has changed to the forecast through early next week. Global ensembles continue to favor ridging to our east through the weekend with a stronger ridge developing over the Southeast for next week. This pattern will support southerly flow through the weekend and deep moisture over the Southeast with PWAT values near or above 2 inches. This setup tends to give the forecast area scattered, diurnal thunderstorms. Convective coverage may be a little higher on Saturday with some potential shortwave energy set to ride up over the ridge into the southern Appalachians. Widespread severe weather continues to not be expected but the biggest threats being isolated downburst winds and locally heavy rain. Height rises early next week should work to suppress convective coverage with just isolated to widely scattered thunderstorms each afternoon. Temperatures will be about 3 to 8 degrees above normal for much of the forecast period, with heat indices approaching the triple digits but still cooler than the first week of September.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

VFR conditions continue through this evening. Brief restrictions possible Friday morning.

VFR conditions are seen across the area as a SCT to BKN cumulus deck has developed. Winds have been light and a bit variable, but should settle generally out of the south to southwest late this afternoon into the evening. A stray shower or two cannot be ruled out, but probabilities for impacts at any of the terminals is rather low. Light winds and VFR conditions likely continue this evening and tonight, though southwesterly flow should continue to advect moisture into the region. This brings the low chance for brief restrictions early Friday due to stratus and/or fog, mainly near the southeastern Midlands and OGB. Probabilities for ceiling restrictions across guidance are rather low (20-40%) at the moment, thus have opted to leave out mention of MVFR or IFR ceilings for now. Any patchy restrictions should clear through the morning Friday with light winds turning out of the southwest. Chances for showers/storms and associated restrictions should increase just after this TAF period.

EXTENDED AVIATION OUTLOOK...Rain chances increase into the weekend along with a higher probability for morning fog/stratus concerns due to higher atmospheric moisture.

CAE WATCHES/WARNINGS/ADVISORIES

SC...None. GA...None.