596 FXUS62 KFFC 161626 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA Issued by National Weather Service Jackson MS 1126 AM EST Thu Dec 16 2021 .UPDATE... A cold air damming wedge remains entrenched across northeast Georgia this morning, but will gradually erode as surface high pressure extending through the Carolinas pulls further east into the Atlantic. This will in turn allow surface winds to shift from easterly to out of the south with richer low-level ThetaE and boundary layer moisture streaming back into central and southern Georgia. Weak isentropic ascent atop the CAD boundary will support a continuation of ongoing light showers/sprinkles mainly along and south of the I-20 corridor. Some light precipitation may spread further north as the CAD erodes, but will initially encounter drier air. Associated cloud cover will keep temperatures on the cooler side over northeast Georgia, especially for locations that remain locked in the CAD airmass. Further south, high temperatures are forecast to climb into the low 70s. The ongoing forecast remains on track and only minor adjustments to PoPs were needed. /TW/JAN/ .PREV DISCUSSION... /Issued 640 AM EST Thu Dec 16 2021/ ..12Z Aviation Area Forecast Discussion... PREV DISCUSSION... /Issued 413 AM EST Thu Dec 16 2021/ SHORT TERM /Today through Friday/... A surface 'wedge' front remains over the forecast area. So far the wedge has been relatively dry, but with moisture beginning to be pumped into the area, dewpoints in the mid 40s are mixing with the cold air damming air mass forming waves of low-level cloud cover occasionally draped over the forecast area. Another surge of moisture is expected today as dewpoints in the mid to upper 50s begin pushing in which should do two things. First, it will push back against the wedge front a bit and begin forcing it northward as the supporting surface high pressure in the mid Atlantic states weakens and moves off shore. Second, isentropic lift of the moist air over the wedge air will cool and condensate as it mixes with cooler air below, with lifting also supporting isolated showers across portions of the forecast area today and tonight, mostly for central and eastern Georgia. With the wedge in place temperatures are a bit cooler across the forecast area today and tonight before rebounding Friday as the surface high pressure in the eastern CONUS moves out over the Atlantic and the wedge gives way to a rush of upper 60 dewpoint air. The result will be highs from the low 60s to low 70s today, lows tonight in the 50s, then highs tomorrow in the upper 60s to upper 70s. Thiem LONG TERM /Friday Night through Wednesday/... Southerly surface flow will remain established across the area late Friday into early Saturday with a stalled front to the northwest and southwesterly flow aloft. Rain showers enter the forecast Friday evening as height falls encounter the southerly warm/moist air and isentropic lift aids in the development of light rain showers across the area. The following day, Saturday, in response to an upper level trough moving across the Mid-West, the previously mentioned stalled front begins to move southeastward towards the CWA. PoPs will further increase in coverage and magnitude ahead of the front with much of the CWA seeing rainfall by Saturday night. Diurnal heating, especially across out south counties and dewpoints in the 60s ahead of the front will yield weak instability Saturday afternoon. Bulk shear values of nearly 40kts, MUCAPES of 500 J/kg and weak lapse rates could result in a few strong thunderstorms developing with strong winds gusts just ahead and along the front. Sunday a temperature gradient will occur across the CWA as the front moves southward. Highs in the north Georgia will be in the 50s while high temperatures south of the Fall Line will be allowed to reach the 60s before FROPA. Better CAA behind the front occurs overnight resulting in temperatures Monday much closer to normal -- 50s area wide. Dry weather returns Monday as weak riding builds over the FA. However, rain quickly returns to the forecast area Tuesday as a system from East Texas moves through the Southeast. Precip will likely spread northward as the system passes through the Florida Panhandle with the heaviest rainfall at this time favoring the southern counties through possibly Wednesday. Another round of dry weather is progged to settle in by the latter part of next week. 28 AVIATION... 12Z Update... Moisture from the south will override cooler air in place over TAF sites, resulting in increased low-level cloud cover today and tomorrow. Mostly VFR in place with SCT MVFR CIGs and some ISO IFR CIGs developing. CIG deck between 24 kft expected to give way to widespread SCT009 BKN012 cloud shield after 15Z thorough 03-07Z. VSBYs also expected to drop after 09Z tomorrow morning. Winds shifting SSE between 16-20Z with speeds between 3-8kts. //ATL Confidence...12Z Update... Medium on VSBYs Friday morning. Medium-High confidence on cigs, though variability expected. High on all other elements. Thiem && .PRELIMINARY POINT TEMPS/POPS... Athens 62 51 68 57 / 20 10 10 30 Atlanta 64 54 69 60 / 20 10 10 30 Blairsville 65 49 67 55 / 10 20 10 40 Cartersville 67 53 69 58 / 10 10 10 40 Columbus 70 55 75 61 / 5 10 10 20 Gainesville 63 52 66 59 / 10 10 10 40 Macon 68 52 75 58 / 30 20 10 10 Rome 71 54 70 60 / 5 10 10 40 Peachtree City 66 52 71 58 / 20 10 10 30 Vidalia 72 58 76 61 / 20 20 10 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Thiem LONG TERM...28 AVIATION...Thiem