Area Forecast Discussion
Issued by NWS Atlanta, GA
Issued by NWS Atlanta, GA
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655 FXUS62 KFFC 080749 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 349 AM EDT Wed May 8 2024 ...Morning Area Forecast Discussion... .SHORT TERM... (Today through Thursday) Issued at 343 AM EDT Wed May 8 2024 Challenging forecast for the entire short term period. Weak high pressure remains in place across the CWA this morning. A nearly stationary frontal boundary stretches from the central Great Lakes back through central Texas. A warm front is situated across the northern Mid Atlantic States. All of the SE US and Gulf States remain within the warm sector with an atmosphere very conducive for convection through the short term period. However, timing/coverage is HIGHLY dependent on upstream convection/potential MCS development. Earlier today should be fairly quiet with thunderstorm potential increasing this evening and lasting well into Thursday. 500mb analysis shows shortwave ridging beginning to move offshore. One mid level low is across the upper Plains states and the second is across the central Great Lakes. The Great Lakes low is expected to move eastward across New England and the upper Plains slow will move east-southeast through the period. The main energy with these two low pressure systems should remain well to the north of the CWA. However, models are progging a strong shortwave to drop southeast overnight Wednesday into early Thursday. Thickness values during this time definitely indicate the potential for a MCS moving across portions of the CWA. Since most of the convection during the short term period is dependent upon upstream activity and any development of an MCS, the forecast will be very challenging. The models have been fairly consistent from run to run showing an MCS dropping southeast from the TN Valley late Wednesday/early Thursday morning. However, not quite sure the hi-res models have a great handle on the evolution of this system. The HRRR has a couple of distinct waves of convection, with one them the MCS in question. The waves of convection are fairly close together and an earlier system could definitely impact the evolution of a later system. The first system could move SE across northern portions of the state Wednesday evening and into the overnight hours. A secondary wave of convection is progged to approach northern portions of the state early Thursday morning, near 12Z...potentially the main MCS. This system moves southeast across much of the CWA during the day. The evolution of this system is VERY dependent upon any earlier convection. If the evening/overnight wave holds together and does impact portions of north/northeast GA, this area could get worked over fairly well before the main MCS moves through. However, if the wave doesn`t hold together, northeast portions of the CWA will have the same potential for severe weather the remainder of the CWA when the main MCS is forecast to move through. Do think the potential for hazardous weather will be greater with the main MCS that begins to move through early Thursday morning and continues southward through the day. All of the parameters will be there for severe thunderstorms with any waves/MCS that impact the CWA overnight and early Thursday. There will be plenty of moisture, forcing, shear and instability. Mid level lapse rates are impressively steep. The primary hazards for severe thunderstorms haven`t changed from previous days, but timing will be somewhat difficult to nail down until these systems actually develop and are able to sustain themselves. Generally, think the best chances for more widespread storms/severe will be with the main MCS push. Any activity that develops ahead of the main MCS will also have the potential to become severe, but maybe not have the potential to be as widespread. Damaging wind gusts and large hail will be the primary hazards. There will also be potential for tornadoes. Locally heavy rainfall is a given. NListemaa && .LONG TERM... (Thursday night through Tuesday) Issued at 343 AM EDT Wed May 8 2024 A cold front will be situated across north Georgia at the start of the period Thursday night. There may be some ongoing convection within the area during this time, dependent on how development trends evolve Thursday afternoon. The focus for later Thursday night into Friday morning will then turn to the potential for an MCS that could approach from the west. A shortwave will initiate convection across east Texas into Louisiana which may congeal into a convective complex and race eastward Thursday evening through early Friday morning as supported by much model guidance. Still, uncertainty remains regarding this scenario as well as the track of said convective complex if it occurs; however, SBCAPE and bulk shear parameters would be supportive of a damaging wind threat if this scenario manifests. The areas most likely to experience impacts in this case would likely be our Middle Georgia counties and points southward to the Gulf Coast. The cold front will make further southward progress on Friday, shunting lingering PoPs largely to southern portions of the CWA by the afternoon. Some potential for strong to isolated severe may remain Friday afternoon in southern zones, though this will depend to some degree on how any morning MCS impacts evolve. By Friday evening, the front should finally clear the area and put an end to the rainfall. In the wake of the front, northwest flow aloft will persist through the weekend while high pressure builds in at the surface. A noticeably drier and cooler airmass will bring temperatures slightly below to near normal through the weekend. Drier conditions may be relatively short-lived, however, as high pressure departs eastward by Monday and southerly low-level flow returns. An approaching shortwave will begin to increase PoPs to our west on Monday, and trends may support PoPs higher than currently forecast by Monday in future forecast cycles. An unsettled pattern then looks likely to continue thereafter. RW && .AVIATION... (06Z TAFS) Issued at 100 AM EDT Wed May 8 2024 Cig forecast will be a challenge tonight like in previous nights. Cloud debris from earlier convection to the north and some sct mid level clouds could disrupt the northern surge of MVFR/IFR clouds from the SW if they thicken. Will leave in the bkn MVFR deck, and tempo the lower IFR deck. The higher res models have backed off the lower IFR cigs but confident enough to remove. Pops remain too low to mention for much of today, but things get challenging overnight and early Thursday with MCS potential. Winds remain on the west side. //ATL Confidence...06Z Update... Med confidence cigs. High confidence remaining elements. NListemaa && .PRELIMINARY POINT TEMPS/POPS... Athens 89 69 81 64 / 20 40 60 30 Atlanta 88 70 80 66 / 10 40 70 40 Blairsville 81 64 77 57 / 30 70 70 30 Cartersville 87 67 82 60 / 10 60 70 40 Columbus 91 73 85 68 / 10 20 70 50 Gainesville 86 69 80 65 / 20 50 70 30 Macon 91 71 85 66 / 10 20 70 40 Rome 87 68 83 62 / 20 80 80 30 Peachtree City 89 70 81 63 / 10 30 70 50 Vidalia 93 72 90 70 / 10 20 60 50 && .FFC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...NListemaa LONG TERM....RW AVIATION...NListemaa