Area Forecast Discussion
Issued by NWS Atlanta, GA
Issued by NWS Atlanta, GA
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317 FXUS62 KFFC 131031 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 631 AM EDT Mon May 13 2024 ...New 12Z Aviation Discussion... .SHORT TERM... (Today through Tuesday) Issued at 358 AM EDT Mon May 13 2024 Key Messages: - The slight risk for severe weather today has shifted southward and out of central Georgia. - High temperatures should be 8 to 12 degrees below seasonal averages today. - Isolated severe storms may occur in the region Tuesday afternoon and evening. Today and Tonight: An upper level trough will track gradually from the Central Plains towards the Tennessee Valley during this period. Lift ahead of the trough should help generate widespread precipitation in the Southeast over the next 36 hours. Guidance from the HREF favors the development of two MCSs in the vicinity of a baroclinic zone along the Gulf Coast. Forecaster confidence regarding the timing and track of both MCSs has increased over the last 12 hours and we now expect the most robust thunderstorm activity to be focused over southern Georgia and the Florida Panhandle. Any storms that do occur in central or northern Georgia should be elevated and this will hinder the potential for severe weather. As such the Slight Risk (level 2 of 5) of severe weather that was over parts of central Georgia in the prior SPC outlook has been shifted southward and out of central Georgia in the latest update. A Marginal risk remains, but any severe risk should be very limited. Forecast rainfall totals through tonight have also been reduced due to the decreased convective potential, and we now expect amounts in the 0.20 to 0.90 inch range through 8 AM Tuesday. Cloud cover and scattered rain showers should keep temperatures cool today. High temperatures this afternoon are forecast to be 8 to 12 degrees below seasonal averages. This translates into temperatures in the upper 60s and lower 70s. Tuesday: A weak shortwave trough should rotate around the parent trough in the Tennessee Valley Tuesday morning. This should lead to a relative peak in rainfall coverage in Georgia Tuesday morning. Clearing skies behind the shortwave and diurnal heating should result in the development of scattered thunderstorms Tuesday afternoon. Though mid- level lapse range appear modest (5.5-6.0 C/km), increasing instability (SBCAPE 1000-2000 J/kg) and 0-6 km shear values between 20 and 35 kt could generate a couple of strong or severe thunderstorms. The main hazards with any storms are expected to be damaging winds or hail. The storm prediction center currently has all of Georgia painted with a Marginal Risk (level 1 of 5) for severe weather. Forecaster confidence in isolated severe weather in northern and central Georgia is higher for Tuesday than it is for today. Albright && .LONG TERM... (Tuesday night through Sunday) Issued at 358 AM EDT Mon May 13 2024 We pick up the long term forecast at the end of Tuesday, where some interesting weather may still be ongoing across the CWA. For more details on that, read above. Upper low aloft should be exiting through the night with some lingering storms and showers that should become more isolated as the night progresses. A broad sfc low pressure will be in the process of transitioning across the Appalachians on Wednesday to a new baroclinic zone with the Gulf Stream, so low level moisture will be wrapping into parts of north GA. This will bring some chances of showers, and if the sun breaks out, possibly a storm or two. There also may be some remnant boundaries in place near central Georgia that could be a focus for an isolated storm or 2, especially in the east where the upper level environment would be slightly less hostile. Thursday continues to look mostly clear with highs quickly soaring into the 80s across the CWA. Our next shortwave will arrive along the southern branch of the jet stream on Friday as another wave is passing by in the northern branch over the Great Lakes. Ensembles differ in how these two interact, with some members phasing them a bit, and others leaving the southern shortwave trailing a bit. In terms of the forecast, our SW flow aloft with decent moisture return in basically all solutions brings chances of rain - the question will be just how much and will there be any severe component with it. It will also have big impacts on the weekend forecast, as a wave that lags behind will leave the CWA in a favorable regime for continued diurnally driven precip chances, and another decent shot of rain once the system finally pulls through, but the other solution may leave a boundary near the CWA that could remain a focus for showers and convection through the weekend. As a result, PoPs on Friday are in the likely range, while the rest of the weekend shows chance to slight chance to represent both the uncertainty and the diurnally driven potential. Current forecast rainfall amounts would be 1-1.5" across the CWA, but expect this to change as details become more clear. Lusk && .AVIATION... (12Z TAFS) Issued at 623 AM EDT Mon May 13 2024 The prevailing VFR conditions in the region should transition to a mix of IFR and MVFR conditions (ceilings between 700 and 2000 ft AGL and visibilities of 2 to 6 SM) between 15Z and 20Z today. After 00Z Tuesday widespread IFR conditions are expected. Ceilings may fall below 500 ft between 06Z and 16Z Tuesday. Widespread rainfall is expected between 14Z and 20Z today. Otherwise showers and couple isolated thunderstorms are expected through 18Z Tuesday. Winds should be from the east or southeast (070-150 degrees) at 4 to 12 kt through at least 12Z Tuesday. //ATL Confidence...12Z Update... Overall confidence in the ATL TAF is moderate. High confidence in the wind forecast. Low confidence in the ceiling forecast between 14Z and 20Z today. Moderate confidence in the precipitation and visibility forecasts. Albright && .PRELIMINARY POINT TEMPS/POPS... Athens 61 76 63 81 / 70 70 60 30 Atlanta 63 77 63 78 / 50 70 50 20 Blairsville 57 71 58 73 / 80 90 80 60 Cartersville 61 78 61 78 / 50 80 60 30 Columbus 65 81 66 83 / 70 80 50 10 Gainesville 61 74 63 78 / 70 70 70 40 Macon 64 80 66 83 / 60 80 50 10 Rome 61 79 61 78 / 50 80 60 40 Peachtree City 62 79 63 80 / 50 70 50 20 Vidalia 67 81 70 86 / 60 80 60 20 && .FFC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Albright LONG TERM....Lusk AVIATION...Albright