textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated.

KEY MESSAGES

- 1. Chances for showers/storms continue today into Tuesday before drier conditions begin to move in. A strong storm cannot be ruled out this afternoon and evening.

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

DISCUSSION

Key Message 1: Chances for showers/storms continue today into Tuesday before drier conditions begin to move in. A strong storm cannot be ruled out this afternoon/evening.

The front that passed on Sunday is expected to meander back north a bit as an area of low pressure develops off the SC coast before a sharper trough digs through the eastern US. Another front is expected to accompany this sharper trough, passing tonight into Tuesday morning. Overall, the environment this afternoon/evening is expected to be characterized by PWAT's near 1.70-1.90", increasing deep layer shear near 20-30 kts, and MLCAPE values around 1000 J/kg. As depicted in the 00z HREF solution, upper support and the surface front are expected to bring additional scattered shower/storm development this afternoon, likely continuing into the evening hours. The overall flash flooding risk is lower than previous day's as storm motions are expected to increase to between 15-25 kts. A storm on the strong side with the main risk of strong to damaging wind gusts cannot be ruled out, but overall severe risk is quite limited.

This front moving in from the northwest should bring cooler/drier air into Tuesday, though it may stall out near the southern FA, bringing continued scattered rain chances through at least the first half of the day. PWAT's then likely drop to under 1" Tuesday evening as a surge of dry air moves, leading to drier conditions that likely hold the remainder of the week.

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

Temperatures are expected to rebound a bit closer to normal today ahead of the next front, before falling below normal Tuesday as a push of CAA moves in behind the front. Current NBM guidance has high temperatures Tuesday in the mid to upper 70s, but depending on how far south the front pushes and the timing of the onset of 850mb CAA, temperatures, could trend toward the low to mid 70s as seen in the recent MET/MAV MOS guidance. There is limited change in the temperature outlook through this weekend. The latest LREF cluster analysis remains is decent agreement that the upper ridge currently over the Central US will shift overhead with surface high pressure building in as well. This should bring temperatures that remain below normal Wednesday, but begin steadily raising closer to normal Thursday and into this weekend.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Mix of MVFR/IFR Ceilings This Morning with VFR Conditions and scattered storms this afternoon and evening.

Low ceilings will continue this morning with MVFR ceilings for the Columbia terminals and a mix of IFR/MVFR ceilings elsewhere. While there were some light isolated showers overnight, they have generally shifted east of the terminals and expect mostly dry conditions through the morning. With northwesterly flow developing aloft, some drier air will be moving in which will help to scour out the low clouds into the afternoon with VFR conditions expected to return to all the terminals. As another front drops into the area late this afternoon into evening, isolated to scattered thunderstorms will develop so have continued the prob30 for all the terminals. With decreasing instability into tonight, thunderstorms will decrease in coverage, although showers will continue, generally remaining light and unlikely to cause significant restrictions.

EXTENDED AVIATION OUTLOOK...Restrictions possible into Tuesday, then drier air begins to move into the region mid to late week.

CAE WATCHES/WARNINGS/ADVISORIES

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