textproduct: Columbia

WHAT HAS CHANGED

Precipitation chances increase through the rest of the week. Updated aviation for 06z TAF issuance.

KEY MESSAGES

- 1. Seasonal temperatures with increasing thunderstorm chances as the week goes on.

DISCUSSION

KEY MESSAGE 1: Seasonal temperatures with increasing thunderstorm chances as the week goes on.

The pattern begins to transition today as an upper-level trough approaches from the west and the previously stalled boundary lifts northward across the area. Increasing low- and mid-level moisture will support a rise in PWATs to around 1.5-1.75 inches, resulting in a greater potential for diurnally driven showers and thunderstorms. Temperatures are expected to remain near normal; however, increasing dewpoints and humidity will bring back a more muggy feel through the remainder of the week.

Moisture advection increases further Thursday as persistent southerly flow transports additional moisture. HREF and LREF guidance suggests PWATs approaching 2 inches, supporting a very moist environment. A shortwave traversing the area will also help provide additional large-scale forcing, with numerous showers and thunderstorms expected across much of the FA. Given the high moisture content and potential for slow-moving or training convection, localized flash flooding will be possible. The WPC currently places portions of the western FA, and areas near the CSRA, in a Slight Risk for Excessive Rainfall, with the remainder of the area in a Marginal Risk. The overall severe threat should remain limited, though an isolated strong storm cannot be ruled producing damaging wind gusts.

Numerous thunderstorms will again be possible Friday as the upper- level trough and associated forcing shift eastward ahead of an approaching cold front. Convection should gradually diminish late this weekend as drier air begins to filter in behind the front. A strengthening ridge is expected to build early next week, promoting a warmer and drier trend as temperatures trend back above average.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

Brief restrictions possible early this morning with scattered thunderstorms developing this afternoon.

Latest satellite imagery indicates patchy MVFR clouds, generally east of the terminals, although very close to OGB. Restrictions will be possible at times at all the terminals, although appear most likely at AGS and OGB, which has already seen some brief MVFR ceilings to this point. This is associated with a low level moisture increase with southeasterly flow over the forecast area. Moisture will continue to increase into today with scattered thunderstorms developing this afternoon. Have continued the prob30 group at all the terminals for the thunderstorm potential. Chance that convection lingers into tonight but for now the most likely timing for storms will be generally from 3 to 8pm. While restrictions will be possible tonight, they are likely to develop after 06z.

EXTENDED AVIATION OUTLOOK...Scattered storms each afternoon through this weekend.

CAE WATCHES/WARNINGS/ADVISORIES

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