textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 12Z TAFs

KEY MESSAGES

- 1. Elevated fire weather concerns today behind yesterday's front.

- 2. A warming trend is expected through the late week before temperatures fall closer to normal with a backdoor front moving in late Friday.

DISCUSSION

KEY MESSAGE 1: Elevated fire weather concerns today behind yesterday's front.

Increased fire danger is expected through the day today as a dry air mass remains in place behind yesterday's front. Dewpoints have fallen between 20-30 degrees in the past 4-6 hours and RH values as of writing this remain between 25-30% with northeasterly winds gusting to 20-25 mph. Heading into the remainder of the morning, these gusts are expected to continue before weakening some through the afternoon as the surface gradient weakens some. Persistent northerly to northeasterly flow and solid mixing this afternoon should yield RH values between 20-25% and with the antecedent dry conditions/fuels, this yields elevated fire weather concerns today. Due to this, a Fire Danger Statement will be in effect starting at Noon, continuing into this evening.

KEY MESSAGE 2: A warming trend is expected through the late week before temperatures fall closer to normal with a backdoor front moving in late Friday.

Temperatures today look to be a bit below normal, in the low to mid 60s as cool/dry northeasterly flow continues behind Monday's cold front as surface high pressure shifts into the Mid Atlantic. As the surface high shifts offshore and the robust upper ridge near the western CONUS begins shifting a bit eastward, temperatures warm closer to normal Wednesday, in the mid to upper 60s(though this is still 2-5 degrees below normal). While a stray shower or storm cannot fully be ruled out today or Wednesday with the front lingering south of the FA, recent CAM runs have trended drier with PWAT's under 0.75" much of Tuesday before rebounding closer to 1" late Wednesday.

For the late week period, there is solid model and ensemble consensus on warming temperatures through Friday as strong 500 mb height rises on the order of 2-4 dm/12 hour move into the region with the upper ridge out west moving in. This should bring 850mb temperatures near the NAEFS 97.5 percentile Thursday before topping out near the 99th percentile on Friday as low level southwesterly flow becomes fairly persistent. This strong ridge should aid in bringing temperatures back into the upper 70s to lower 80s Thursday before ramping up to the mid to upper 80s on Friday. On Friday, a backdoor cold front is expected to move in and there is decent agreement at this stage across LREF clusters and ensemble guidance that this front should not move in until late in the day. Decent moisture advection is expected ahead of the front with PWAT's reaching near 1-1.25" so isolated showers and possibly a storm or two cannot be ruled out late Friday into Saturday morning. Behind this front, global models depict a strong surface high moving in from the northwest, bringing cooler/drier air. Temperatures over the weekend and into the start of next week are expected to be near to just below normal with dry weather.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

VFR expected through the 24hr forecast period. Breezy this morning.

With the front now well to our south, the flow around surface high pressure over the Mid Atlantic will dominate todays winds. A decently tight pressure gradient this morning will cause gusty northeasterly winds, but as the center of the high settles near the North Carolina coast later today, the wind speeds will diminish and the direction will gradually veer to the east, becoming generally light by tonight. An upper level shortwave will spread mid to high level clouds through the morning as well. but once it passes by, no cigs are expected for late day and overnight.

EXTENDED AVIATION OUTLOOK...VFR conditions are expected for much of the upcoming week.

CAE WATCHES/WARNINGS/ADVISORIES

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