textproduct: Columbia

WHAT HAS CHANGED

Thursday morning precip discussion and Aviation updated.

KEY MESSAGES

- 1) Rain showers continue, with some scattered snow-showers or brief freezing drizzle possible Thursday morning.

- 2) Temperatures near to slightly below average through the weekend followed by a significant warmup next week.

DISCUSSION

KEY MESSAGE #1: Rain showers continue, with some scattered snow- showers or brief freezing drizzle possible Thursday morning.

Broad overrunning downstream of the approaching 500-850 trough, continues across the area, lingering into Thursday morning. These widespread showers should generally yield between 0.75-1.0" qpf for the period with a band of heaviest qpf likely towards the back edge of the main precip line later this evening. Overnight, the 850mb and surface trough will pivot east and drive some notable cold advection into the region and drop surface temps back into the 30's. The column will steadily cool through Thursday morning, bringing much of the profile below 700mb between -10-0 C. Enough lingering moisture below 500mb will be present to potentially produce some snow showers or rain showers will with near freezing surface temps; HREF guidance is mixed on whether or not the cloud layer will be cold enough to produce snow growth, even if below freezing. Therefore the potential for a mix of snow showers and/or brief freezing rain is possible from roughly 6am-10am, primarily Lancaster and Chesterfield counties; the HRRR brings a few snow showers as far south as I-20 but surface temps would mitigate any impacts. Surface temps will be extremely borderline in either scenario so impacts are expected to be minimal. So the risk continues to remain low enough though that a winter weather advisory does not appear necessary at this time.

KEY MESSAGE #2: Temperatures near to slightly below average through the weekend followed by a significant warmup next week.

No notable changes made to the previous forecast. Overall expect temperatures to be near average through the weekend, quite the change from the significant cold spell for the Midlands and CSRA over the last week or so. The exception will be behind the front Thursday which likely be colder with an upper trough over the forecast area, with NAEFS mean indicating 500mb heights will be below the climatological 10th percentile. Upper ridging late this weekend will begin to build over the central US with blended guidance favoring a quick return to above average temperatures by the middle of next week.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Restrictions expected to persist through the 24 hour TAF period.

An area of rain will continue to move through the region through tonight. The increased moisture will all but guarantee low CIGS, with occasional VSBY reductions due to -RA or -DZ and BR. Expect widespread MVFR/IFR CIGS into this evening, followed by predominant IFR/LIFR CIGS overnight into Thursday morning. While precip will end from west to east overnight, CIGS are expected to remain reduced with IFR restrictions continuing through the morning. Generally SLY surface winds around 5 to 10 knots are expected today before relaxing a bit after 00z. Winds will shift to the northwest and north generally between 00-03z when the front pushes through the region. North to northeast winds then prevail on Thursday around 10 kts.

EXTENDED AVIATION OUTLOOK...Restrictions likely continue the first half of Thursday and drier air moves in behind the front. Returning dry air should bring low chances for restrictions Thursday night into this weekend.

CAE WATCHES/WARNINGS/ADVISORIES

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