textproduct: Columbia

KEY MESSAGES

- 1. Temperatures well above normal expected through the early to mid week next week.

- 2. Diurnal rain chances begin tomorrow afternoon, continuing into next week.

DISCUSSION

KEY MESSAGE #1: Temperatures well above normal expected through the early to mid week next week.

The robust ridge is now building overhead and will continue to do so into Friday and Saturday. Temperatures this afternoon should top out in the upper 70s to lower 80s before warming further (the low to mid 80s) to end the week and start the weekend. This comes as the upper ridge continues to strengthen into the weekend to nearly 2 standard deviations above normal and 850mb temperatures reach 8-12 degrees above average. The ridge should weaken some Sunday and through early next week, but well above normal temperatures in the 80s are expected to continue with persistent southwesterly flow and 850 mb temperatures remaining anomalously warm. The mid week is expected to remain warm as well, though there is a bit more uncertainty as global guidance has more spread in solutions in the evolution of a Baja low.

KEY MESSAGE #2: Diurnal rain chances begin tomorrow afternoon, continuing into next week.

Persistent southwesterly flow becomes a bit more southerly to southeasterly Friday, aiding in bringing PWAT's above 1". The mean HREF solution and high-res guidance indicate diurnal showers and a couple storms should form mainly along the western periphery of the Bermuda high and upper ridge across GA Friday afternoon, but coverage is expected to be less across the FA with stronger influence of the ridge overhead. Heading into this weekend, more diurnal shower/storm chances are expected as the ridge flattens out in response to troughing moving into the Great Lakes region. PWAT's should reach 200-220% of normal by Sunday as deep southwesterly flow remains in place. A weak cold front may near the region on Sunday, bringing additional forcing, but confidence in this feature making it to the FA is low at this time. This pattern likely continues into the early week with warm/humid conditions lingering. The main change comes after Tuesday and into the mid week as greater ensemble and cluster spread is seen in the evolution of a Baja low. At this time this upper low and any potential surface response does not look to move into the region until after Wednesday, but timing differences still exist. Overall, expect diurnally driven showers/storms mainly this weekend and into early next week where the overall threat for organized severe weather is low. A bit more organized system could begin nearing the FA during the mid to late week but high uncertainty exists out to that timeframe.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Lingering MVFR stratus through 19z possible, otherwise VFR until Friday morning before IFR-LIFR stratus-fog expected.

The pattern has not changed much the last few days with high pressure to our east, continuing to push low level moisture with drier air aloft into the area. This led to widespread fog- stratus that has mixed out to MVFR cigs for all sites; VFR expected everywhere after 19z. Winds will remain out of the southwest throughout the afternoon and evening before going calm overnight. Another round of low cigs stratus and fog is expected Friday morning with IFR-LIFR conditions expected after 09-10z for all sites, lasting through roughly 15z. Like Thursday, it will likely be a mix of fog and stratus as winds between 1-2k feet will remain elevated to prevent a pure fog event.

EXTENDED AVIATION OUTLOOK...Patchy morning fog remains possible each day. Increased shower chances expected for the weekend and into early next week.

CAE WATCHES/WARNINGS/ADVISORIES

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