textproduct: Columbia

WHAT HAS CHANGED

High confidence in well above normal temperatures into next week. A bit more uncertainty in pattern after Tuesday next week. Aviation discussion updated for 18Z TAFs.

KEY MESSAGES

- 1. Above normal temperatures through early to mid next week. - 2. Chance of diurnal showers tomorrow into next week.

DISCUSSION

KEY MESSAGE #1: Above normal temperatures through early to mid next week.

A robust ridge is overhead and will remain in place Friday and Saturday. This will lead to temperatures well above normal with highs in the low to mid 80s through the remainder of the week and to 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: Chance of diurnal showers tomorrow 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 /00Z FRIDAY THROUGH TUESDAY/

We continue to have deeply layered high pressure over the area, which will promote another round of low clouds and fog beginning in the predawn hours and lingering through a chunk of the morning, before gradually lifting and scattering. The lowest morning vsbys are likely in the usual vulnerable locations of AGS and OGB, but cigs will be very low anyway, providing LIFR conditions for a while.

Friday afternoon there is a slightly better chance for showers, but still low enough to leave out of the TAFs for now.

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.