textproduct: Columbia

WHAT HAS CHANGED

Minimal change to Key Messages, lower chance for thunderstorms this afternoon/evening. Aviation discussion for 06z TAF issuance updated.

KEY MESSAGES

- 1. Chances for showers/storms continue tonight and again this afternoon before drier conditions move in by this evening, continuing the remainder of the week.

- 2. Below normal temperatures today and Wednesday behind a front before a warming trend is expected into this weekend.

DISCUSSION

Key Message 1: Chances for showers/storms continue tonight and again this afternoon before drier conditions move in by this evening, continuing the remainder of the week.

Scattered showers and storms are on-going across the FA tonight with a more invigorated line of convection moving out of the southern Midlands. While elevated instability is waning and DCAPE values are less than 400 J/kg, a well defined, but compact shortwave is driving this line, which is exiting the CWA. Behind this, scattered showers and possibly a weak storm may continue for the coming hours as the shortwave works through and a cold front currently moving into the Pee Dee sinks through the region. This front is expected to bring cooler/drier air, but this is lagging behind back in central NC. The overall risk for flash flood remains low with progressive storm motions, but nuisance flooding or ponding cannot be ruled out with the efficient rain rates seen in convection.

The front is expected to generally stall just southwest of the CSRA through the day today, keeping PWAT's between 1.0-1.25" south and west of the I-26 corridor, but instability is forecast to be meager at best. As shown in the 00z mean HREF solution, this may bring isolated to scattered showers in the aforementioned area during the afternoon before drier air really pushes in this evening with PWAT's dropping to under 0.75" for much of the region. With this push of drier air late this afternoon into the evening, a gusts winds with gusts to 20-25 mph could be possible. There remains fairly high confidence in dry conditions prevailing the remainder of the work week and into this weekend as a ridge builds overhead.

Key Message 2: Below normal temperatures today and Wednesday behind a front before a warming trend is expected into this weekend.

The push of CAA behind the front currently working into the area is expected to work in beginning early this afternoon, keeping temperatures below normal, in the mid to upper 70s. Some locations may reach the low 80s depending on how fast cloud cover moves out this afternoon into this evening. Lingering 850mb CAA into Wednesday is expected to bring another day with below normal temperatures in the upper 70s to low 80s. After this, there is good agreement across global models that the current Omega blocking pattern across the CONUS will break down and the strong upper ridge over the central US will progress eastward. Strong high pressure near the NAEFS 90-97th percentile will also move into the region, aiding in bringing warming temperatures that near normal by Friday, continuing into this weekend and possibly early next week.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

Showers shifting south of the terminals with MVFR restrictions possible this morning

Lingering showers moving over the terminals and will shift southward over the next several hours as a cold front ushers in drier air from the north. Guidance has been fluctuating on the potential for restrictions this morning and it appears the most likely scenario for most of the terminals will be temporary MVFR ceilings and visibilities, although can't completely rule out brief IFR ceilings. As drier air pushes in near daybreak, restrictions will decrease. Increasing northeasterly winds expected today with gusts around 20 knots possible behind the cold front. VFR conditions expected to continue through the rest of the TAF period after daybreak.

EXTENDED AVIATION OUTLOOK...Drier air returns to the region mid to late week with mainly VFR conditions expected.

CAE WATCHES/WARNINGS/ADVISORIES

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