textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for the 00z TAF issuance.

KEY MESSAGES

- 1. A front will bring breezy winds Thursday and frost/freeze potential late this week into the weekend.

DISCUSSION

Key Message 1: A front will bring breezy winds Thursday and frost/freeze potential late this week into the weekend

The southern stream shortwave is currently nearing the area on WV imagery with its out of phase northern counterpart diving into the mid Mississippi Valley. The first cold front is currently situated across southern IN/IL and will continue eastward overnight. Ahead of the front, a meager moisture response is expected with PWAT's remaining near to just shy of 1". The expectation of mostly dry conditions into Thursday morning remains, but cannot rule out a very spotty shower ahead of the front. As the front moves through early Thursday, a tightening pressure gradient develops with a surface low shifting into the Mid-Atlantic. A robust 30-40 kt LLJ is also expected to develop overnight tonight into Thursday, but soundings indicate a strong inversion should prevent this from mixing down until late Thursday morning. Once the inversion breaks, BUFKIT soundings indicate westerly gusts to 25-30 mph should begin mixing down. Conditions are expected to fall just short of Lake Wind Advisory criteria across area lakes, but isolated gusts toward 30 mph could be possible.

A secondary front is expected to move in late Thursday into early Friday morning, bringing much drier air and a push of CAA that is expected to influence temperatures through early next week. In general, the two frontal passages are expected to yield temperatures that cool the remainder of the week with temperatures Thursday remaining in the low to mid 70s before dropping into the upper 50s to low 60s Friday and finally the mid to upper 50s this weekend into early next week. As has been advertised, this northwesterly flow regime and the associated CAA favors frost potential Saturday and Monday mornings and a possible freeze Sunday morning. NBM probabilities for low temperatures less than 32F Sunday morning remain around 25-50% across the area, highest (50 to 75%) in the northern Midlands while probabilities for low temperatures less than 35F are up to 50-70% Saturday, Sunday, and Monday mornings. The need for frost/freeze products this weekend and early next week will continue to be monitored.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Expecting a continuation of VFR the next 24 hours with a period of low level wind shear expected tonight.

Satellite imagery and surface observations indicate SCT-BKN clouds around 10kft MSL this evening, though some clearing is noted west of the terminals. Do not anticipate any low level cloudiness through the period at this time, so VFR is expected to continue. A strong low-level jet is expected to develop over the next several hours as a front nears the region. This will likely generate llws around 35 kts around 1-2kft MSL much of the overnight, with surface winds from the S/SW around 4-7 kts. Once the inversion breaks around 14z Thursday, these stronger winds will mix to the surface, and WLY winds will increase to 10-15 kts, with gusts 20-25 kts increasingly common at all terminals. Given mixing in the boundary layer, no fog concerns tonight. The frontal boundary passage tomorrow should be mostly dry, so very low chances for precip continue.

EXTENDED AVIATION OUTLOOK...Dry air will likely prevent widespread restrictions through the extended. Gusty winds expected again into Friday as a cold front passes.

CAE WATCHES/WARNINGS/ADVISORIES

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