textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 12z TAF issuance.

Minimal change to the fire weather outlook today. There is a small chance temperatures tonight near the mid 30s in the Pee Dee, but frost headlines are not expected at the moment.

KEY MESSAGES

- 1. A Red Flag Warning is in effect for critical fire conditions today.

- 2. Temperatures warm into the mid week with slight chances for rain entering the forecast.

DISCUSSION

KEY MESSAGE 1: A Red Flag Warning is in effect for critical fire conditions today.

At the time of writing this, the cold front is working through the FA from the northwest, seen from the sharp wind shift toward the north and then northeast behind it with gusts to 25-30 mph as strong CAA pushes in. As expected, dew points have not been quick to fall, but values toward the mid 30s are already seen creeping into north central NC. Strong CAA and a tightening surface pressure gradient will continue through this morning as northeasterly winds likely gust to 25-30 mph where isolated gusts to 35 mph cannot be ruled out. After daybreak, the push of robust dry air is expected with dew points quickly falling into the 20s through the morning and finally toward the upper teens by this afternoon. This should bring RH values that fall toward 15-20% by this afternoon. As has been messaged in earlier discussions, surface winds are expected to gradually weaken through the morning and into the afternoon with the lowest RH values coming during the late afternoon. Still, a sustained period of 25+ mph winds and RH less 25% is expected starting by the late morning, continuing throughout the afternoon. This will bring critical fire weather conditions across the FA, where a Red Flag Warning remains in effect starting at 8 AM this morning, continuing until 11 PM this evening. Winds significantly weaken tonight and become more easterly to southeasterly, allowing slightly better moisture to move in, but recovery is not expected to be all that impressive into Sunday morning.

As a reminder, in conjunction with the Red Flag Warning, SC and GA have issued burn ban notices that are in effect until further notice.

KEY MESSAGE 2: Temperatures warm into the mid week with slight chances for rain entering the forecast.

Temperatures become closer to normal to slightly below normal today and Sunday behind the cold front as a robust Canadian surface high begins moving into the region. One thing worth noting is, decent radiational cooling conditions could be possible tonight toward the Pee Dee especially and this will allow temperatures to fall into the upper 30s for much of the FA, but parts of the Pee Dee could near 33-37F. With dew points likely still in the low to mid 20s tonight, this makes frost formation fairly unlikely, but trends with temperatures and moisture return will continue to be monitored in case a small Frost Advisory is needed.

Heading into the week, a familiar pattern takes shape as upper ridging near the NAEFS 90th percentile moves in with the surface high gradually shifting off shore. This should bring a return to southerly to southwesterly low level flow and temperatures that warm back above normal through at least the mid week. Global models and ensemble guidance indicate that as the FA finds itself on the western periphery on the surface high and upper ridge by late Tuesday, moisture makes a return to the area with GEFS and EC Ensemble PWAT's reaching above 170% by Wednesday. Increasing moisture along with a potential front nearing the Southeast sometime in the mid to late week could bring back rain chances to the area by Wednesday.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

VFR conditions will prevail the next 24 hours.

A cold front has pushed south and east of the forecast area this morning, with winds now out of the north to northeast at all terminals. Sustained winds behind the front will generally be between 10-15 knots, and wind gusts around 25 knots, throughout much of the day. Winds will diminish some late this afternoon and into the evening as low-levels decouple slightly. Winds turn more northeast to east after sunset, with speeds becoming lighter and less than 5 knots after 03z at all sites. As for cloud cover, there is still some mid-level moisture and strato- cu behind the front being shown on satellite. Ceiling will remain vfr through the period. Clouds should begin to scatter out late this morning, with mostly clear conditions expected by this afternoon and into the overnight hours tonight.

EXTENDED AVIATION OUTLOOK...VFR conditions likely into early next week as rain chances ramp up by late week.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory until 2 PM EDT this afternoon for SCZ016- 018-020>022-025>031-035-037-038-041-115-116-135>137. Red Flag Warning until 11 PM EDT this evening for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. GA...Lake Wind Advisory until 2 PM EDT this afternoon for GAZ040- 063>065-077. Red Flag Warning until 11 PM EDT this evening for GAZ040- 063>065-077.