Sunrise 6:26 AM   Sunset 8:33 PM Moonrise 4:59 PM   Moonset 3:35 AM

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FXUS62 KFFC 201028 AFDFFC

Area Forecast Discussion National Weather Service Peachtree City GA 628 AM EDT Mon May 20 2024

New 12Z Aviation Discussion

SHORT TERM
(Today through Tuesday)
Issued at 259 AM EDT Mon May 20 2024

As the shortwave to the east makes its grand entrance off the eastern seaboard, a ridge is beginning to stretch across the Ohio and Mississippi River Valleys. This ridge will continue to build in along the spine of the Appalachians through today as a potent negatively tilted shortwave over the Central Plains skirts off over the Great Lakes Region. Surface pressure in the leeside of the Appalachians is already evident in the surface analysis where that is expected to strengthen thanks to the synoptic-scale subsidence. Easterly flow will develop a southerly component through the day, allowing the enhancement of the upslope winds across the northeast Georgia mountains. With considerable moisture remaining in the low levels of the atmosphere, SBCAPE between 500-1000 J/kg in northeast Georgia, and steep low level lapse rates, a few orographically induced storms could initiate off of mountainous terrain. The far northeast Georgia mountains are the only locations in the CWA that are forecast to see any chance at precipitation this afternoon as well as any meaningful cloud coverage. Most locations today will see mostly sunny skies and high temperatures topping out in the low to mid 80s with higher elevations in the 70s. Overnight, enhanced cloud coverage from modest moisture aloft across north Georgia will keep temperatures from dropping much below the mid 60s, even in areas of higher elevations where temperatures are forecast to bottom out in the upper 50s. Areas further south across central Georgia will see low temperatures closer to the 60 degree mark thanks to clear skies allowing for longwave radiation to cool the surface more efficiently.

Tuesday, a seasonably warm and sunny day is forecast for the forecast area. Despite winds out of the southeast, surface moisture is lacking, thus limiting chances for orographically induced showers and thunderstorms across northeast Georgia again. Have maintained a low end slight chance for precipitation across extreme northeast Georgia as some moisture remains around the 850mb level. Otherwise, dry conditions are anticipated areawide. Maximum daily temperatures will climb into the mid to upper 80s areawide outside of elevated terrain, where temperatures will remain in the 70s.

KAL

LONG TERM
(Tuesday night through Sunday)
Issued at 259 AM EDT Mon May 20 2024

The long term period begins with a longwave ridge across much of the eastern CONUS. This ridge will extend from the northwest Gulf of Mexico into the Deep South and then northeastward towards New England. Surface high pressure associated with this ridge will be centered to the northeast of the forecast area. Subsidence underneath this high will largely serve to inhibit precipitation through Wednesday. With increasing 1000-500 mb thicknesses under the ridge combined with plenty of sunshine, a warming trend will continue on Wednesday. After starting the morning in the low to mid 60s across the majority of the area, high temperatures on Wednesday afternoon are forecast to rise into the upper 80s. Temperatures will be locally cooler in the higher elevations of far northeast Georgia.

While weather conditions will be benign across north and central Georgia on Wednesday, a deepening upper low will be moving from the upper Midwest towards the Great Lakes region. The axis of the ridge will meanwhile clear Georgia to the east by late Wednesday, at which point southwesterly upper flow between the low and the ridge will enter north Georgia, leading to increasing atmospheric moisture. As the low pressure system becomes occluded and moves into southeast Canada, a cold front will advance slowly southward into the Tennessee Valley region by Wednesday night. Isolated to scattered showers and thunderstorms will begin to advance into far north Georgia by early Thursday morning as a weak disturbance traverses the upper-level flow and overruns the frontal boundary. PoPs on Thursday and Thursday night will mostly be confined to far north Georgia, with low-end chance PoPs in the far northern tier and and progressively lower chances to the south. Even in spite of increased cloud cover across far north Georgia near the front, the warming trend will persist, with highs forecast to be in the upper 80s in north Georgia and low 90s in central Georgia. These high temperatures will be consistent with what can be expected for the remainder of the week and into the weekend, which will run about 4-8 degrees above climatological normals.

As the low continues to move away to the northeast, the frontal boundary will become more elongated from west to east, and its southward advance will begin to slow. By Friday morning, the frontal boundary is forecast to stall near the Georgia/Tennessee state line.
A more robust shortwave will traverse the westerlies and from the Lower Mississippi River Valley across the Southeast on Friday into Friday night. This setup is likely to bring more numerous showers and thunderstorms to the forecast area on Friday, especially where wave overruns the stalled frontal boundary, providing a focus for additional convection. Uncertainty still remains in the model guidance with respect to the strength and exact position of this disturbance, which will influence where the most widespread precipitation will occur. While the frontal boundary will begin to dissipate by early Saturday morning, additional disturbances will continue to traverse the westerlies and through the Southeast this weekend. Scattered showers and thunderstorms are thus expected on both Saturday and Sunday, with the highest chances during the afternoon each day where diurnal instability will be greatest.

King

AVIATION
(12Z TAFS)
Issued at 622 AM EDT Mon May 20 2024

VFR conditions through TAF cycle. Cumulus field will develop around 14Z with FEW040-050 through the afternoon before becoming FEW250 overnight. Light E/SE winds at 5KT or less throughout TAF cycle becoming calm to VRB03KT during the overnight hours. Cumulus field returns tomorrow during the afternoon at KATL.

//ATL Confidence
12Z Update
High confidence on all elements.

KAL

PRELIMINARY POINT TEMPS/POPS
Athens 60 86 60 87 / 0 0 0 0 Atlanta 64 86 64 87 / 0 0 0 0 Blairsville 59 80 57 83 / 10 10 0 0 Cartersville 63 87 62 88 / 0 0 0 0 Columbus 63 86 63 88 / 0 0 0 0 Gainesville 63 85 62 86 / 0 0 0 0 Macon 60 85 61 88 / 0 0 0 0 Rome 62 87 62 88 / 0 0 0 0 Peachtree City 60 86 61 88 / 0 0 0 0 Vidalia 62 85 62 88 / 0 0 0 0

FFC WATCHES/WARNINGS/ADVISORIES
None.

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