textproduct: Columbia

WHAT HAS CHANGED

Showers and thunderstorms will move through the area this morning, departing to the north east mid-day.

KEY MESSAGES

- 1. Thunderstorms expected this morning, damaging winds are possible but overall the severe weather threat is low.

DISCUSSION

Key Message 1: Thunderstorms expected this morning, damaging winds are possible but overall the severe weather threat is low.

A slow moving cold front just to our west will continue pushing through the forecast area this morning and throughout the day. Divergence aloft and convergence ahead of the front will help increase convective activity this morning. A few broken showers are currently moving through the northern Midlands, with a couple of embedded thunderstorms. Activity should remain fairly isolated before guidance suggest a surge of moisture/forcing overspreading the area across eastern Georgia and then into the Midlands just before sunrise and continue through midday. The overall severe threat remains low due to poor low-level lase rates; however, the wind field will continue to strengthen over the next few hours, helping to erode the nocturnal inversion. If convection is able to become surface based, there is the potential for a couple of stronger storms capable of producing damaging winds or possibly a weak tornado.

REFS mean SBCAPE values range from 250 to 750 J/kg this morning, while midlevel flow increasing to around 30-40 kts will support effective shear around 35 kts. This will provide some support for organized convection as storms along the front move into the moist downstream airmass across the eastern Carolinas. The greatest threat will likely be in the Pee Dee and northeast region of the FA where daytime heating will improve low level lapse rates prior to the frontal passage as well as cooling aloft. However, this may be somewhat limited as cloud cover could suppress stronger destabilization during the day. Mean QPF from the NBM and REFS still generally show 0.25 to 0.5 inches with localized higher amounts of around 1 inch in the PMM where thunderstorms develop.

The front should push offshore during the evening hours, allowing drier and cooler air to return. A rain-free forecast is expected to remain in place through early next week, with dry conditions and seasonable temperatures favored over the next several days.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Restrictions in place through the morning, improving mid-day.

Showers and thunderstorms are moving through the forecast area this morning. This will produce periodic visibility restrictions at all TAF sites. Thunderstorm coverage is limited but lighting in the VC of the sites is possible. Convection will move northeast of the TAF sites by 15Z. As the associated cold front works through the region, MVFR cigs are likely with a few hours of IFR possible during the early morning. We will see some ceiling improvement mid-day before lifting to VFR in the afternoon. As the front passes there will be a pair of wind shifts: first a shift to W/WNW winds behind the cold front, then another shift this evening to the N as a secondary boundary pushes in from NC. Dry air and decent mixing should hinder fog development overnight, keeping conditions VFR.

EXTENDED AVIATION OUTLOOK...Dry air will likely prevent widespread restrictions through the extended.

CAE WATCHES/WARNINGS/ADVISORIES

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