Area Forecast Discussion
Issued by NWS Atlanta, GA
Issued by NWS Atlanta, GA
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951 FXUS62 KFFC 221040 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 640 AM EDT Wed May 22 2024 ...New 12Z Aviation Discussion... .SHORT TERM... (Today through Thursday) Issued at 344 AM EDT Wed May 22 2024 The ridge that`s been bringing our quiet weather over the last few days will begin to break down with the axis pushing off to the east as a potent low pressure system moves over the Great Lakes Region. While the ridge breaks down today, generally quiet, dry, and warm conditions are expected to persist. Despite a bit more cloud coverage today compared to the mostly sunny skies earlier this week, temperatures are expected to climb into the upper 80s in most areas and into the 70s in higher elevations. Overnight, a weak system to the west over the Tennessee Valley will stall out. Moisture aloft will be advected into our forecast area and cloud coverage will continue to increase. Overnight lows will be a bit elevated as a result, where most locations will see temperatures in the upper 60s. Thursday as a weak disturbance ripples within the 500mb flow and the aforementioned boundary moves across Tennessee, the southern extent of precipitation is expected to bring a chance of precipitation to north Georgia. Scattered showers, as well as a few thunderstorms, are currently forecast. With warm surface temperatures in the mid to upper 80s, sufficient SBCAPE (~1000-1500 J/kg), 30-40kt of bulk shear, and southerly flow bringing plentiful low-level moisture, a few thunderstorms could become strong (where an isolated storm cannot be ruled out at this time). As such, SPC has placed our northern tier of counties in a Marginal Risk (Level 1 out of 5) for severe weather with damaging wind gusts being the primary hazard of concern. KAL && .LONG TERM... (Thursday night through Tuesday) Issued at 344 AM EDT Wed May 22 2024 Much of the extended period will be characterized by an active and progressive flow pattern. On Thursday night, a cold front advancing through the Tennessee Valley will begin to stall as its occluded parent low moves away into eastern Canada. A shortwave disturbance traversing the upper level west-southwesterly flow will be moving northeastward away from north Georgia and towards the Mid-Atlantic coast, at which point showers and thunderstorms across the far northern tier should diminish to isolated coverage overnight. Morning low temperatures on Friday are expected to be in the mid to upper 60s across the majority of the forecast area. By Friday morning, dewpoints will similarly be in the mid to upper 60s, while precipitable water values will climb to around 1.5 inches. The relative lull in precipitation will be short-lived. By Friday morning, the upper flow will become more zonally oriented and the frontal boundary will become more elongated from west to east, and stalling near the Georgia/Tennessee state line. A more robust shortwave will traverse the westerlies across Alabama and into Georgia on Friday. This setup is likely to bring more numerous showers and thunderstorms to north Georgia on Friday, especially where the wave overruns the stalled frontal boundary, providing a focus for additional convection. At this time, at least chance PoPs are forecast across the northern half of the forecast area by Friday afternoon, with likely PoPs across the far northern tier. With high temperatures ranging from the mid 80s in far north Georgia to the low 90s in east-central Georgia will contribute to SCAPE values as between as high as 1500-2000 J/kg during the peak heating hours. Furthermore, with deep-layer bulk shear values between 30-40 kts, there is the possibility that a few storms could become strong, capable of producing gusty winds and hail. Additional perturbations will traverse the quasi-zonal upper flow 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. PoPs each afternoon will range from high-end chance to low-end likely in north Georgia, with lower chances in central Georgia, although uncertainty remains with the evolution and movement of the upper level disturbances. By late Sunday, a shortwave trough and associated surface low moving northeast from Missouri towards the Great Lakes will extend a cold front into the Lower Mississippi River Valley. Deep atmospheric moisture will continue to increase in the warm sector late Sunday into Monday. The cold front is forecast to enter far north Georgia by Monday morning, where it will provide a focus for more organized showers and thunderstorms which could produce severe weather and locally heavy rain. Rainfall totals through Monday are forecast to range from 1 to 2 inches roughly along and north of I-20, with lower amounts to the south. It should be noted that with high PWATs, stronger storms that occur could produce locally heavier amounts, which could cause localized flooding concerns. High temperatures this weekend and into Monday will range from the mid 80s across far north Georgia (where cloud cover will be greatest) to the low 90s in central Georgia each day. These highs will run mostly 4-8 degrees above climatological normals. King && .AVIATION... (12Z TAFS) Issued at 622 AM EDT Wed May 22 2024 VFR conditions throughout TAF cycle. FEW/SCT cumulus field developing after 14-15Z before becoming FEW/SCT 250 after sunset. Light SE winds will become more S/SW this morning at 5KT or less where winds will slacken to VRB03/calm overnight. //ATL Confidence...12Z Update... High confidence on all elements. KAL && .PRELIMINARY POINT TEMPS/POPS... Athens 66 87 68 88 / 0 20 10 30 Atlanta 68 88 69 88 / 0 10 10 30 Blairsville 62 80 62 81 / 10 40 20 60 Cartersville 66 88 66 88 / 0 20 10 40 Columbus 68 90 68 89 / 0 0 0 10 Gainesville 67 86 68 86 / 0 20 10 40 Macon 67 90 69 89 / 0 0 0 10 Rome 66 87 66 87 / 10 20 20 50 Peachtree City 67 89 67 88 / 0 10 10 20 Vidalia 68 90 70 91 / 0 10 0 10 && .FFC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...KAL LONG TERM....King AVIATION...KAL