Area Forecast Discussion
Issued by NWS Atlanta, GA
Issued by NWS Atlanta, GA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
439 FXUS62 KFFC 211049 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 649 AM EDT Fri Jun 21 2024 ...New 12Z Aviation Discussion... .SHORT TERM... (Today through Saturday) Issued at 340 AM EDT Fri Jun 21 2024 As the morning begins, a broad upper level ridge remains positioned over much of the eastern CONUS. Much of the Southeast is under the influence of surface high pressure and relatively dry air underneath this ridge. Meanwhile, a small but concentrated area of showers and thunderstorms is ongoing in association with a low pressure roughly 200 mi to the east of the Georgia/Florida coast. As the ridge pattern retrogrades to the west and begins to dampen, the disturbance will be steered to the west-northwest at around 10-15 mph by the flow around this ridge. The NHC currently gives this disturbance a 50% chance of tropical development in the next 48 hours, as environmental conditions are marginally conducive to further development into a short-lived tropical depression. In the meantime, low temperatures will start the morning in the mid to upper 60s across the majority of the area, and conditions across north and central Georgia will remain dry through the morning. With only scattered cloud cover developing in the afternoon and increasing 1000-500 mb thicknesses in the high- pressure regime, high temperatures will climb into the low to mid 90s this afternoon, with the exception of cooler temperatures in the higher elevations of far northeast Georgia. As the disturbance draws closer to the coast by this afternoon, it will bring an influx of tropical moisture into east-central Georgia, with dewpoints increasing into the upper 60s to low 70s and precipitable water values increasing to above 1.5" in the far southeast corner of the forecast area. The increase in atmospheric moisture, combined with MUCAPE values of 500-1000 J/kg will be sufficient for isolated to scattered thunderstorms in east- central Georgia - to the immediate west of the advancing low - in the afternoon hours today. The absence of any notable low level shear or deep-layer bulk shear suggests that the development of strong to severe thunderstorms will be unlikely this afternoon. By Friday evening, the center of the low is anticipated to be centered near the Georgia/Florida coast, at which point it is likely to begin to slowly meander northward Friday night and into Saturday. Moisture advection will persist overnight and into Saturday as dewpoints in the 70s and precipitable water values between 1.5-1.7" continue to spread further north and west into the forecast area. High temperatures will also continue their steady climb, reaching into the mid 90s across the majority of the forecast area on Saturday afternoon. The combination of warming temperatures and increasing moisture could have heat index values pushing 100 in some locations. The combination of increasing moisture, MUCAPE values between 750-1250 J/kg, and frictional convergence near around the low pressure system will lead to a greater chance of showers and thunderstorms on Saturday. At this time, PoPs are mainly confined to the south of the I-85 corridor where these ingredients all come together. The coverage of showers and thunderstorms will be greatest in the far southeast (likely PoPs), with progressively lower coverage to the north and west. King && .LONG TERM... (Saturday night through Thursday) Issued at 340 AM EDT Fri Jun 21 2024 No significant weather impacts or forecast concerns are expected in the long term period. Most recent medium range guidance still has large E-W oriented ridge in place over 30-35 deg N latitude over the CONUS thru Monday at which point strong upper ridging builds in the SWUS and W TX and weak troughing over the eastern CONUS including Georgia and Carolinas. Could see a weak front try to slip in Sun night and early Monday with some lingering overnight convection. Not seeing anything too strong with the storm environment at this time. Models also showing a more pronounced wave very late in the forecast moving SE in NWly flow from the Midwest states into the SEUS on Wed. As mentioned previously, this NW flow pattern on the east side of a strong upper ridge is favorable for MCS development and maintenance overnight. Global ensembles still show signs this may occur, Tues night, Wed and/or Wed night. Most favorable area for more significant strong/severe storms may end up to our west but still plenty of time for new observations upstream to adjust later forecasts. Also not seeing any clear tropical activity in the Atlantic basin or GOM through the long term period. May become more active around the end of the month over the Caribbean but that remains very uncertain. SNELSON && .AVIATION... (12Z TAFS) Issued at 646 AM EDT Fri Jun 21 2024 VFR conditions are expected to persist through the TAF period, with a FEW-SCT cu field around 050-060 developing during the afternoon hours. Chances for SHRA/TSRA are forecast to remain south and east of all TAF sites today. Winds will be primarily E through the period, at 5 kts or less during the morning hours and increasing to 6-10 kts after 17Z, then diminishing to 5 kts or less once again after sunset and overnight. IFR level clouds will be possible in the morning hours on Saturday, between 10-14Z, in east Georgia. These scattered IFR clouds could spread as far east as MCN/AHN towards the end of the TAF period. //ATL Confidence...12Z Update... Medium confidence on IFR clouds on Saturday morning. High confidence on all other elements. King && .PRELIMINARY POINT TEMPS/POPS... Athens 69 93 72 95 / 0 10 10 20 Atlanta 71 95 75 97 / 0 10 0 20 Blairsville 64 89 67 89 / 10 10 0 20 Cartersville 69 95 72 96 / 0 10 0 10 Columbus 72 96 74 99 / 0 20 10 20 Gainesville 69 93 72 94 / 0 10 0 20 Macon 71 94 72 98 / 0 30 10 30 Rome 71 97 72 97 / 0 10 0 10 Peachtree City 69 95 72 97 / 0 10 0 20 Vidalia 74 91 73 96 / 30 80 20 60 && .FFC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...King LONG TERM....SNELSON AVIATION...King