textproduct: Columbia

WHAT HAS CHANGED

Confidence increased for near record temperatures on Friday. Cold front late in week continues to trend mostly dry but brings fire weather concerns this weekend. Aviation discussion updated for 12Z TAFs.

KEY MESSAGES

- 1. Temperatures warm through Friday, before a cold front brings back cooler/drier to the region for this weekend. Temperatures likely rebound again early next week.

- 2. Fire weather concerns enter this weekend behind the front with very dry air and breezy winds moving in.

DISCUSSION

KEY MESSAGE 1: Temperatures warm through Friday, before a cold front brings back cooler/drier to the region for this weekend. Temperatures likely rebound again early next week.

After a cool morning in the low to mid 40s for much of the area (upper 30s in the northern FA), temperatures begin to warm today through Friday. Upper ridging inches closer today, with low level flow becoming a bit more southeasterly as surface high pressure begins moving off shore. This should allow temperatures to return to near normal, in the upper 60s to low 70s. 500mb height rises ramp up Thursday, and especially Friday as 500mb heights exceed the NAEFS 90th percentile and 850 mb temperatures near the NAEFS 99th percentile by Friday. These factors along with increasing southwesterly flow should allow temperatures to reach the low to mid 80s on Thursday, before topping out in the upper 80s Friday, which could be within a couple degrees of daily records for CAE/AGS. This near record warmth Friday is highlighted in the recent EC EFI with values exceeding 0.90 and a Shift of Tails (SOT) of 1. There remains fairly good agreement across ensemble guidance and global models on the timing of the strong cold front with this moving through late Friday and into early Saturday. The front continues to look mostly dry with slight chance to chance PoP's mainly across the Pee Dee region considering the timing. Behind the front, much cooler/drier air moves in as strong surface high pressure (near the NAEFS climatological max) moves into the region. Temperatures are expected to be a touch below normal this weekend before following a similar pattern as this week, with warming temperatures into the start of next week.

KEY MESSAGE 2: Fire weather concerns enter this weekend behind the front with very dry air and breezy winds moving in.

As the strong cold front moves in late Friday, a tightening pressure gradient takes shape as robust 1036-1038mb high pressure moves into Midwest. This is expected to bring breezy winds by Friday afternoon that ramp up further Friday night into Saturday as the gradient tightens even further with the surface high moving closer. The latest EC Ensemble mean solution shows a swath of 25-30 mph gusts during this period, while the GEFS is a bit less aggressive, but still showing gusts exceeding 20-25 mph. This surface high originating from western Canada brings a very dry airmass where LREF probabilities for RH values under 25% exceed 60% for much of the FA. The latest EC Ensemble is a bit more aggressive, but in general displays a similar story. Overall, confidence is increasing that breezy northeasterly winds will be seen behind the front, coinciding with minimum RH values that near or fall below critical values Saturday afternoon. When this is coupled with dry fuels from the prolonged drought conditions across much of the area, enhanced fire weather concerns are expected especially Saturday. Near to below critical RH values seem likely again Sunday, but winds look to be much weaker.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

VFR conditions generally expected through the 24hr forecast period except possible brief MVFR stratus this morning AGS/DNL.

High pressure centered off the Mid-Atlantic coast continues to ridge into the forecast area. Persistent northeasterly flow continues with slightly more easterly flow aloft off the Atlantic which is producing weak isentropic lift and resulting in VFR stratocumulus ceilings at the terminals with some patchy MVFR cigs across GA which may impact DNL/AGS through 15z. Northeast winds around 5 to 7 knots expected today gradually shifting more southeasterly by afternoon. Expect at least scattered VFR ceilings to persist through the afternoon, especially at AGS/DNL and continuing overnight.

EXTENDED AVIATION OUTLOOK...Mainly VFR conditions are expected for the second half of the week. Another cold front will move through Friday night, ushering in another reinforcing cool and dry air mass for the weekend. Some gusty winds are possible Saturday behind the front.

CAE WATCHES/WARNINGS/ADVISORIES

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