174 FXUS62 KFFC 191150 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 750 AM EDT Sun Apr 19 2020 .PREV DISCUSSION... /issued 400 AM EDT Sun Apr 19 2020/ ..Another Significant Severe Event Anticipated Today... SHORT TERM /Today through Monday/... Would definitely classify the current state as the calm before the storm across the area as high pressure remains in control over the Carolinas with influence over the local area resulting in a continued dry northerly flow. Dewpoints hardly of the severe variety thus far with upper 30s and lower 40s the rule. All this points to a scenario in which area will be on the edge of surging moisture and energy but also means demarcation of these 2 zones later today will be an area primed for severe storms including tornadoes and damaging winds. Initially, it will be just an isentropic lift scenario with S to SW flow of 50 kts at 5k ft stream over the relatively cold dome mentioned above. All CAPE will be of the elevated variety but still sufficient for some thunder for Central portions. Things will change very quickly however through the early afternoon hours with a very sharp gradient of energy developing. Although surface based CAPE will remain near zero all the way down to the southern metro, we will see values in excess of 2000 J/KG approaching our far SW zones. The STP will be increasing to around 5 during this time as well allowing for a start to the tornado threat as well as damaging winds. Further north of this, up to I20, the pure dynamics of this system may be enough to overcome the relative lack of instability. Shear may prove to be too high the further north you go as updrafts will simply not be able to support. However, damaging winds will remain a likely component for the Atlanta metro and other areas along the I20 corridor. Main event looks to be along the front later in the evening for Central GA as instability and corresponding STP surges northward briefly. Although overall geographic footprint of this system may be smaller than last system, this one is not to be taken lightly by any means as tornadoes look likely along and south of a Columbus to Macon line. In addition, a few strong and long track tornadoes will be possible given sigtor ramping up during this timeframe and updraft helicities represented by most of the hi res guidance. Rapidly improving conditions for late Sunday night into Monday although winds will be gusty in cooler NW flow. Deese LONG TERM /Monday Night through Saturday/... Tuesday will be dry and somewhat windy favoring N GA with some areas close to wind advisory criteria(20 mph sustained). The next system of concern will be on Thursday as surface low pressure and associated short wave approach the area. There looks to be a sharp gradient of instability as the warm front gets stuck over central GA. This system will need to be monitored for severe weather potential as we get closer. Either way, another period of wet weather can be expected starting Wednesday night and maximizing Thursday into Thursdsay night with just small chances for lingering light showers briefly on Friday. Models are inconsistent with another system approaching on Saturday and precip currently favoring n GA is very much a compromise. BDL HYDROLOGY... The Flash Flood watch will be continued due to the potential for heavy rainfall over central and portions of n GA. 2 to 5 inches of rain can be expected with locally higher amounts. Some of the rain could occur in a short period of time. Heavy rainfall will likely lead to localized flooding. Flooding of low-lying areas, creeks and streams can be expected with additional larger river rises anticipated as well, well after the rain ends. .AVIATION... 12Z UPDATE... A challenging forecast to say the least with multiple waves of SHRA and TSRA likely across the terminals today. Anticipate the first of these to accompany lowering cigs this morning with MVFR developing. Will be some TSRA with this first wave for sure and will include in TEMPO group. Will handle most of the TSRA in Prob30 group and utilize 2 Prob30 groups for MCN and CSG to account for severe line of storms late this evening and potential gusts to 45kts. If anything, cigs go down even further later Sun evening as some LIFR potential will accompany the final wave of SHRA/TSRA. //ATL CONFIDENCE...12Z UPDATE... Medium on TSRA timing. High on remaining elements. Deese && .PRELIMINARY POINT TEMPS/POPS... Athens 61 55 72 49 / 90 100 70 0 Atlanta 63 56 70 50 / 100 100 60 0 Blairsville 59 49 65 44 / 80 100 70 0 Cartersville 62 53 70 47 / 100 100 60 0 Columbus 71 61 76 51 / 100 100 50 0 Gainesville 58 53 71 48 / 90 100 70 0 Macon 68 60 76 51 / 100 90 60 0 Rome 62 53 71 47 / 90 100 60 0 Peachtree City 65 57 72 48 / 100 100 60 0 Vidalia 73 65 77 56 / 100 90 70 5 && .FFC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from 11 AM EDT this morning through Monday morning for the following zones: Baldwin...Barrow...Bibb... Bleckley...Butts...Carroll...Chattahoochee...Clarke...Clayton... Cobb...Coweta...Crawford...Crisp...DeKalb...Dodge...Dooly... Douglas...Emanuel...Fayette...Glascock...Greene...Gwinnett... Hancock...Haralson...Harris...Heard...Henry...Houston...Jasper... Jefferson...Johnson...Jones...Lamar...Laurens...Macon...Marion... Meriwether...Monroe...Montgomery...Morgan...Muscogee...Newton... North Fulton...Oconee...Oglethorpe...Paulding...Peach...Pike... Polk...Pulaski...Putnam...Rockdale...Schley...South Fulton... Spalding...Stewart...Sumter...Talbot...Taliaferro...Taylor... Telfair...Toombs...Treutlen...Troup...Twiggs...Upson...Walton... Warren...Washington...Webster...Wheeler...Wilcox...Wilkes... Wilkinson. && $$ SHORT TERM...Deese LONG TERM....BDL AVIATION...Deese