Sunrise 6:29 AM   Sunset 8:35 PM Moonrise 4:07 PM   Moonset 3:15 AM

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FXUS62 KFFC 191048 AFDFFC

Area Forecast Discussion National Weather Service Peachtree City GA 648 AM EDT Sun May 19 2024

New 12Z Aviation Discussion

SHORT TERM
(Today through Monday)
Issued at 345 AM EDT Sun May 19 2024

An elongated, positively tilted 500 mb shortwave is currently moving over the forecast area at the time of writing. Positive vorticity advection in the base of the trough, weak upper level divergence, and an abundance of moisture in the lower levels are helping to initiate a few light showers over far north Georgia early this morning. The otherwise moist surface conditions thanks to yesterday evening's round of rain and calm winds have produced patchy areas of intermittent dense fog across the forecast area. A few locations this morning have had visibilities reduced to less than a quarter statute mile. Have opted to issue an SPS for areas along and north of the I-85 corridor through 10am local time given the spotty and intermittent nature of the dense fog. An upgrade for some areas to a Dense Fog Advisory may be warranted if visibilities continue to deteriorate over the course of the next few hours.

Light shower activity will continue to drift southward early this morning as the trough moves eastward bringing showers to the metro during the mid morning hours (though an isolated rumble of thunder cannot be ruled out). The progression of the upper level trough will also help the surface low slide a surface boundary southeastward and serve as the focus for showers and thunderstorms across eastern central Georgia during the late morning/early afternoon hours as surface instability is reinvigorated through diurnal heating (SBCAPE ~1000-2000 J/kg). With better forcing at the surface and some upper level support, there could be a few strong thunderstorms across eastern central Georgia where the seabreeze may infiltrate later this afternoon. A Marginal Risk has clipped a handful of our far southeastern counties where an isolated severe thunderstorm cannot be ruled out today.

Overnight, as the system makes its exit off the eastern seaboard, ridging aloft will become established along the spine of the Appalachians as surface high pressure develops in the leeside. While most locations will experience sunny, dry weather on Tuesday, upslope orographic convective initiation will produce a low end chance for isolated showers and thunderstorms across far northeast Georgia in the afternoon hours. QPF through the period will hover +/- a quarter of an inch where locally higher amounts of a 1.0+" are possible in areas of convective activity today and tomorrow. Today's high temperatures will be in the upper 70s to low 80s, but will rebound tomorrow closer to normal where high temperatures will be in the low to mid 80s. Overnight lows will run in the upper 50s to low 60s.

KAL

LONG TERM
(Monday night through Saturday)
Issued at 345 AM EDT Sun May 19 2024

On Monday night, the positively tilted upper trough will continue to move eastward into the Atlantic as an upper ridge sets up over the eastern CONUS. By the beginning of the long term period, this ridge will extend from the north-central Gulf into New England. A weak shortwave will traverse the flow on the northwest side of the ridge.
However, any sensible impacts from this disturbance will stay well to the north of the forecast area. Surface high pressure associated with the ridge and centered to the northeast of the forecast area will also largely serve to inhibit precipitation from Monday night into Tuesday. After low temperatures start the morning on Tuesday in the upper 50s to low 60s, a warming trend can be expected through midweek. Highs are forecast to climb into mainly the mid 80s on Tuesday afternoon, and then into the upper 80s on Wednesday afternoon. Temperatures will be locally cooler in the higher elevations of far northeast Georgia. High temperatures through the remainder of the long term period will range from the mid 80s in north Georgia to the low 90s in south-central Georgia each afternoon.

A deepening upper low will move from the northern Plains towards the Great Lakes region on Wednesday, at which time the axis of the ridge will clear Georgia to the east. 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.
Scattered showers and thunderstorms will begin to spread into far north Georgia by early Thursday morning. 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. As such, PoPs on Thursday will mostly be confined to north Georgia, with chance PoPs to the north of I-20 and progressively lower chances to the south. By Friday morning, the frontal boundary is forecast to stall near the Georgia/Tennessee state line. Model guidance appears to be coming into better agreement on a shortwave traversing the westerlies and from the Lower Mississippi River Valley across the Southeast on Friday. This setup would bring more numerous showers and thunderstorms to the forecast area on Friday, especially the wave overruns the stalled frontal boundary, providing a focus for additional convection.King

AVIATION
(12Z TAFS)
Issued at 639 AM EDT Sun May 19 2024

LIFR/IFR cigs/vsbys across northern terminals with MVFR/VFR conditions elsewhere. Improvement to MVFR at northern locations will occur by noon where CSG/MCN will see MVFR earlier by mid morning. TEMPO for -SHRA at metro/AHN terminals from now until ~16Z. Low end chance for -TSRA during this time frame but not enough confidence to include in the TAF. -TSRA for MCN later this afternoon/early evening. Calm/NW winds will become NE after 13Z at northern locations and this afternoon/evening at MCN/CSG. Winds will be light at 5KT. VFR conditions return this evening with FEW/SCT IFR/MVFR at end of period.

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

KAL

PRELIMINARY POINT TEMPS/POPS
Athens 59 82 59 85 / 0 0 0 0 Atlanta 61 83 62 85 / 0 0 0 0 Blairsville 56 79 57 81 / 20 20 0 10 Cartersville 60 84 60 86 / 20 0 0 0 Columbus 64 84 62 86 / 10 0 0 0 Gainesville 61 82 62 84 / 10 10 0 0 Macon 61 83 61 86 / 10 10 0 0 Rome 61 85 61 87 / 10 0 0 0 Peachtree City 60 83 59 86 / 0 0 0 0 Vidalia 64 83 62 85 / 20 10 0 0

FFC WATCHES/WARNINGS/ADVISORIES
None.

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