textproduct: Columbia

WHAT HAS CHANGED

Updated aviation for 12z 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.

More of the same is expected today as the region remains on the dry side of a sfc boundary. Northerly low-level flow will continue to advect drier air, while subsident vertical profiles remain unfavorable for deep convection. Afternoon mixing will keep dewpoints suppressed into the 60s, with daytime temps remaining near normal. A few isolated thunderstorms could develop east of I-95 this afternoon, where proximity to the front and slightly greater moisture may support limited development.

By Wednesday, moisture will begin to increase as the stalled boundary to our south moves back overhead and reactivates. LREF probabilities indicate a 50-70 percent chance of PWAT values exceeding 1.75 inches. Low-level winds will veer to the south/southwest, allowing dewpoints and afternoon humidity to return to more typical summertime levels. Combined with increasing upper- level troughing and moistening profiles, this should support increasing chances for scattered showers and thunderstorms beginning Wed afternoon and through the remainder of the week.

Models remain in good agreement on the overall increase in convective coverage, though uncertainty remains regarding the day-to- day timing and location of more robust convection. A widespread organized severe threat appears low; however, stronger to marginally severe storms cannot be ruled out each day. Damaging winds and heavy rainfall producing localized flash flooding will be the primary concerns. Overall, daily precip chances will remain in the high chance to likely range through the week, with some decrease possible this weekend. Temperatures should remain near normal, while increasing dewpoints will bring a return to more muggy conditions.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

VFR conditions are expected to continue through the TAF period.

A stalled front remains east of the terminals which has led to drier air in place with dew point depressions relatively high early this morning compared to the last several days. This leads to higher confidence in VFR conditions continuing through the TAF period with northeasterly winds, shifting to more southeasterly this evening and a few high based cumulus, around 7kft during the day, dissipating after sunset. Moisture begins to return tonight which could lead to brief restrictions near sunrise tomorrow.

EXTENDED AVIATION OUTLOOK...Isolated storms each afternoon with higher coverage of storms expected by midweek.

CAE WATCHES/WARNINGS/ADVISORIES

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