textproduct: Columbia

WHAT HAS CHANGED

Dangerous heat expected into Friday with daytime highs in the upper 90s to around 100 and Heat Index values between 105 and 110. The Heat Advisory is in effect through 8PM Friday. Aviation discussion updated for 00z TAFs.

KEY MESSAGES

- 1. Heat Indices between 105-110F expected Friday.

- 2. Rain chances pick back up this weekend and early next week.

DISCUSSION

- 1. Heat Indices between 105-110F expected Friday.

Ridging is more directly overhead on Friday which should help to suppress convective development. MOS guidance shows temps near 100 again Friday with similar dewpoints to the previous day. This will likely lead to another day of dangerous heat with Heat Index values between 105 and 110.

Increased diurnal shower/storm chances into the weekend and early next week limit confidence in the need for additional heat products, but either way, above normal temperatures are expected to continue into early next week as the ridge likely does not become more flattened out until around the mid week.

- 2. Rain chances pick back up this weekend and early next week.

Global ensembles continue to favor ridging slowly flattening into early next week, with more chances for shortwaves and/or weakening MCSs to near the FA in a northwest flow regime. PWATs will likely remain near or above 2 inches through the late weekend into next week. This synoptic setup will favor at least isolated to widely scattered convection. There is some indication in global models that troughing could develop over portions of the eastern toward the middle of the week shifting to a wetter pattern.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

VFR conditions likely outside of scattered convection this evening.

Isolated to scattered showers and thunderstorms have been impacting taf locations this afternoon. Activity will persist the next hour or so, then should diminish. Brief mvfr conditions possible in showers/storms, the vfr expected outside of activity the remainder of the night and through Friday.

Stratus/fog Friday morning can not be completely ruled out, especially with the rainfall today. However guidance not really indicating this, and confidence in widespread restrictions remains low. Have thus kept vfr at this time. Winds become light and variable to calm overnight, the increase after sunrise out of the west.

EXTENDED AVIATION OUTLOOK...Diurnal chances for thunderstorms continue each day through the weekend.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Heat Advisory until 8 PM EDT Friday for SCZ016-018-020>022- 025>031-035-037-038-041-115-116-135>137. GA...Heat Advisory until 8 PM EDT Friday for GAZ040-063>065-077.