textproduct: Columbia

WHAT HAS CHANGED

Inverted key messages, otherwise the forecast remains on track. Aviation discussion updated for the 18z TAF issuance.

KEY MESSAGES

- 1. A front will bring mostly dry and breezy conditions this afternoon and evening. - 2. Frost/Freeze headlines could be needed this weekend, especially Sunday morning.

DISCUSSION

Key Message 1: A front will bring mostly dry and breezy conditions this afternoon and evening.

Winds picked up late this morning as the pressure gradient tightening ahead of the secondary cold front is now passing across the forecast area, with gusts up to 25 to 30 mph observed at times in the past couple of hours. These gusts will continue through the afternoon as a 35-40 kt LLJ passes eastward and weakens. Gusts reaching Lake Wind Advisory criteria across area lakes this afternoon should remain isolated in nature. Westerly winds should gradually weaken this evening and tonight.

Key Message 2: Frost/Freeze headlines could be needed this weekend, especially Sunday morning.

The secondary cold front passing through the area will bring much drier and colder airmass on Friday, with dewpoints falling into the 30s. Much cooler than normal temperatures are expected Friday, through the weekend, and into early next week. High temperatures each day through Tuesday should remain in the mid to upper 50s with lows in the low 30s to low 40s. On Saturday morning, westerly winds around 5 mph should hold lows in the mid to upper 30s, which precludes Freeze Watches for now, but Frost Advisories may be needed. There is increasing confidence across deterministic and AI global ensembles that lows Sunday morning should dip into the low 30s, with multiple locations dropping to freezing, especially across the northern FA. Temps on the lower end of guidance would be favored by clear skies and light winds less than 5 mph. The main question is how far the surface high is displaced to our northwest, but even solutions keeping it further northwest in the LREF cluster. Freeze Watches are looking increasingly likely for much of the forecast area for Sunday morning, especially across the western & northern Midlands and northern CSRA. Overnight lows into the 30s are expected into early next week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Vfr conditions expected through the period. Only a few to scattered mid-level clouds this afternoon as a front moves through. Winds overnight will preclude any fog formation. Due to this, vfr conditions will prevail.

Biggest aviation issue this afternoon and evening will continue to be the sustained winds and associated wind gusts at all taf locations. Current observations continue to show sustained winds generally between 10-15 knots, with gusts between 20-25 knots at times. Expecting this to continue towards sunset, then as low levels begin to decouple the both the sustained and gusts should diminish some, but not all together. Winds gusts should be about done by 06z, with sustained winds the remainder of the night around 5 knots. Model sounding time sections do not show as strong of a low-level jet overnight, with the max only around 25 knots above 1 kft, so as long as surface winds do not go calm and the jet isn't stronger, do not anticipate any issues with llws tonight. Gusty winds will then return again through the day Friday associated with the post frontal gradient. EXTENDED AVIATION OUTLOOK...Dry air will likely prevent widespread restrictions through the extended.

CAE WATCHES/WARNINGS/ADVISORIES

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