FXUS64 KJAN 291126 AAA AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 526 AM CST Tue Nov 29 2022 ...New AVIATION... .DISCUSSION... Issued at 324 AM CST Tue Nov 29 2022 Today and Tonight...The potential for a significant severe weather event has further expanded across the forecast area this morning. Conditions across the region will quickly moderate up under strong southerly flow at the surface and even stronger southwest flow aloft today. This will result in deep moisture surging northward into the region. Warm advection shower activity is likely to get an early start, along with some isolated thunderstorms over the area by late morning as a frontal boundary lifts north from the coast. All of this is in response to a strong mid/upper level jet moving into the region, along with an increasing low level jet, ahead of a strong mid/upper level trough that'll swing east across and out of the central and southern plains states through the day. This trough will then eject northeast across the Mid-Mississippi River Valley and Mid- South region towards the Great Lakes region through Wednesday morning. This will result in a deepening surface low that'll quickly lift northeast from the central plains into the Great Lakes region this afternoon into tonight. As it does so, it'll drag a cold front into and through the CWA late tonight into Wednesday morning. Ahead of the front, very sufficient shallow (30-40 kts, 0-1 km & 40- 50 kts 0-3 km) and deep-layer (50-65 kts, 0-6 km) wind shear will exist, resulting in long looping Hodographs with storm-relative helicity values between 300-400 m^2 s^2, along with more than adequate for this time of year (1000-1700 J/kg MLCAPE), and steep mid-level lapse rates (6.5-7.0 C/km, 700-500 MB). All of the above will set the stage for a long duration severe weather event, where significant severe weather will be possible across a large portion of the forecast area from early this afternoon through early Wednesday morning. A "Moderate Risk" for severe storms has been expanded to include the majority of our forecast area. Severe weather is expected, with significant severe weather consisting of tornadic supercells producing strong tornadoes...some possibly significant and long- tracked, damaging wind gusts to 80 mph, and golf ball to tennis ball size hail all possible. Surrounding this "Moderate" and covering much of the remainder of the CWA, is an "Enhanced Risk" for severe storms. Here, damaging winds to 70 mph, tornadoes...some possibly strong, and quarter to golf ball size hail will all be possible. In addition to this, a "Flash Flood Watch" has been hoisted for a portion of Southeast Mississippi from 15Z today through 12Z Wednesday. Here, 2-3 inches of rain, with locally higher amounts, are possible. A good portion of this area has already observed 3-5 inches of rain over the past week. With these forecasted rainfall totals through early Wednesday morning, it could easily result in some flash flooding across the area, especially is multiple storms move across the same areas. The cold front will finally push through the forecast area through the course of Wednesday morning. Cooler, drier, and quiet conditions will gradually fill into the CWA in the wake of the front as high pressure at the surface will quickly build into area. With rain in the process of exiting Southeast Mississippi by sunrise, lows will range from the lower 40s across the Delta to the lower 60s across Southeast Mississippi Wednesday morning. /19/ Wednesday through Monday...a dry continental polar airmass will bring seasonably cool temperatures to the forecast area with readings expected to be several degrees below climate normals. Thereafter, expect the airmass to quickly modify as an anomalous subtropical ridge builds over the Gulf of Mexico and adjacent coastal region. Another polar cold front should approach from the north and imfringe on the ridge as we go through the weekend and into early next week. This should result in shower chances across northern portions of the area, and with the surface front likely hanging up just to our north, we can expect very mild daytime highs continuing into early next week. /EC/ && .AVIATION... (12Z TAFS) Issued at 526 AM CST Tue Nov 29 2022 Flight categories will remain degraded through the remainder of the forecast period as showers and storms increase across the area, with significant severe thunderstorms capable of producing damaging wind gusts to 70 knots, strong tornadoes...with long- tracked significant tornadoes possible, and golf ball to tennis ball size hail all possible. Gusty south winds sustained between 13- 17 knots, gusting to between 21-26 knots at time, will be observed away from thunderstorms throughout the late morning, afternoon, and evening hours. Winds will remain gusty overnight into early Wednesday morning, but they'll become northerly after the passage of the cold front. /19/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 75 49 63 34 / 80 100 0 0 Meridian 73 54 67 33 / 80 100 10 0 Vicksburg 75 47 59 33 / 90 90 0 0 Hattiesburg 77 61 70 35 / 80 100 20 0 Natchez 75 50 63 34 / 90 80 0 0 Greenville 71 41 52 32 / 80 60 0 0 Greenwood 72 43 55 32 / 90 90 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... None. && $$ 19