textproduct: Columbia

WHAT HAS CHANGED

Added discussion of ongoing showers and a few storms. Aviation discussion updated for the 00z TAF issuance.

KEY MESSAGES

- 1. Showers are expected through Friday with a few thunderstorms also possible Thursday and Friday.

DISCUSSION

Key Message 1: Showers are expected through Friday with a few thunderstorms also possible Thursday and Friday.

A shortwave is currently translating around a larger scale trough and progressing through central GA, which is providing enough energy to produce some widely scattered showers across the area. Additionally, a few thunderstorms are approaching the CSRA due to this shortwave. However, a majority of the activity should stay to our west overnight as the main front remains relatively stationary over the Blue Ridge Mountains.

Showers should pick back up Thursday as the front shifts further east and continued moisture advection promotes convection in the diurnally heated air mass. We expect some destabilization throughout the day but with extensive cloud cover there should not be anything more than weak instability. This will keep updrafts rather weak and limit the threat of severe weather.

The front will finally push through the area on Thursday night through early Friday as an upper level trough advances through the eastern US. There should be some thunderstorms that develop along the front. Divergence associated with the upper trough should be more supportive of convective development than the weakly forced activity in days prior. That said, the nocturnal timing should help keep the low levels stable. We cannot rule out a stronger storm mixing wind gusts down to the surface however severe weather remains unlikely. Dry, cool air will filter into the area Friday afternoon and remain in place through the weekend.

Rainfall amounts which have trended up over the past few days have been relatively steady today. NBM QMD probabilities of one half an inch through Friday morning remain around 40 to 60 percent for areas north and west of I-20. There could be some localized higher amounts on Thursday night and Friday as the front moves through with some elevated thunderstorms.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Similar to Tuesday, VFR conditions are expected to give way to MVFR/IFR conditions again late tonight into Thursday morning with some possible showers as well.

As a cold front approaches from the west scattered showers will be possible through the night into Thursday, although much of the more steady rainfall is expected to remain west of the terminals. However, there is an area of thunderstorms moving through eastern GA which may impact AGS/DNL during the 00-03z time frame so included a tempo there. Otherwise, VFR cigs expected through 06z or so then another round of stratus expected to develop with MVFR/IFR cigs expected after 09z through around 16z. There could be some vsby restrictions also within scattered showers. Winds overnight should be around 5 knots or less from the east to southeast then pick up to around 7 to 9 knots and shift more southerly after 15z as the front moves toward the region.

EXTENDED AVIATION OUTLOOK...Increasing chances for rain particularly again Friday may lead to some lower CIGS or VSBY restrictions. Conditions should improve over the weekend.

CAE WATCHES/WARNINGS/ADVISORIES

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