textproduct: Columbia

WHAT HAS CHANGED

No significant changes to the forecast. Updated aviation discussion for the 18z TAFs.

KEY MESSAGES

- 1. Fire Weather concerns remain elevated through the end of this week as drought conditions persist amid a dry airmass.

- 2. A gradual pattern change is expected late in the forecast period, with increasing rain chances this weekend.

DISCUSSION

Key Message 1: Fire Weather concerns remain elevated through the end of this week as drought conditions persist amid a dry airmass.

Elevated fire weather concerns continue this week as a dry air mass settles over the region with much of the area in severe to extreme drought. While winds will be generally limited with high pressure ridging into the area, high probability of relative humidity dropping below 30 percent each afternoon through Friday. This will make conditions susceptible to increased fire starts. Winds may be a bit stronger Wednesday and Friday as surface boundaries approach the area and these days may require Fire Danger Statements. Regardless of the issuance of these statements, the SC Forestry Commission continues a Burn Ban for South Carolina until further notice.

Key Message 2: A gradual pattern change is expected late in the forecast period, with increasing rain chances this weekend.

The highly amplified 500mb pattern over the CONUS that has persisted the last several weeks will begin to breakdown this weekend as a more progressive pattern takes place. This will lead to several shortwaves working through the forecast area this weekend into early next week. With ensemble mean PWATs generally rising to 125 to 150 percent of normal, this favors increasing chances for rain this weekend. The first of these systems looks to be a cold front arriving late Saturday or Saturday night. This storm appears to be a high PoP, low QPF in nature, meaning the probability of rain is high but that the precipitation likely won't amount to much. We will still likely have a ways to go to break the drought as only a couple GEFS members have greater than an inch of rain through Monday (and we will need more than that). The longer term pattern favors a more active (wetter) pattern through the end of the month and into early May with teleconections such as the NAO, favoring general troughing over the eastern CONUS.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

VFR conditions are expected to continue through the TAF period.

Dry high pressure remains in the region this afternoon with clear skies and northeast winds between 5-9 kts, where a couple gusts up to 15 kts have been noted. These conditions continue through the evening before light winds shift a bit more southerly. Tonight, SCT cirrus should move in with light and variable winds. There is a bit of returning moisture overnight and recent HRRR runs and soundings attempt to show possible patchy fog development near AGS/OGB, but with increased cloud cover, and a 20-25 kt LLJ overhead, the remainder of guidance is not as excited at this prospect so due to this, have left mention of fog out of the TAF at AGS/OGB at this time. After sunrise Wednesday, cirrus gradually clear and winds should pick up around 5-8 kts out of the southwest heading into the afternoon.

EXTENDED AVIATION OUTLOOK...Widespread restrictions are not expected through at least Friday. Possible rain chance move in this weekend, but confidence in any restrictions is low at the moment.

CAE WATCHES/WARNINGS/ADVISORIES

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