126 FXUS64 KJAN 161833 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 133 PM CDT Thu May 16 2024 ...New AVIATION... .MESOSCALE UPDATE... Issued at 936 AM CDT Thu May 16 2024 The forecast remains largely unchanged. The southern jet continues as the positively tilted trough axis across the southern plains is currently helping propagate clusters of showers and storms across Northeast Texas. Throughout the day expect mild conditions in our area with partly cloudy skies prevailing. Expect cloud cover to increase steadily throughout the day from west to east. Winds will shift from southerly to southwesterly strengthening low level- moisture by lifting the warm front north by tonight. Temperatures will warm to the mid 80s to low 90s in the far southeast./KP/ && .DISCUSSION... Issued at 406 AM CDT Thu May 16 2024 Today and Tonight: As an positively-tilted upper-level trough remains situated over the Southern High Plains, shortwave impulses ejecting eastward from it remain the drivers of shower and thunderstorm activity across the region. A jet streak nosing northeastward from central Texas today will accompany one of these waves rounding the base of the trough, lifting a warm front up from the central Gulf Coast through tonight. PWAT values of 2.0 inches and a strengthening low-level jet overnight will result in likely heavy rainfall and flash flooding in the frontal zone. The latest suite of high-res guidance appears to be handling the ongoing overnight convection to our west fairly well. Following through the short-term projections, a west-east oriented complex of storms over central Texas by this afternoon should be spreading south-southeastward through unstable air. Strong westerly deep-layer shear and the lifting warm front along the Gulf Coast should facilitate a more eastward bend to the complex's movement overnight, which will result in the current advertised Marginal Risk for severe thunderstorms across southwestern and southern portions of our forecast area. The potential for damaging wind gusts and possible tornadoes exists, especially if the frontal boundary sneaks into the southern portions of our CWA. Additionally, the heavy rainfall with these storms and boundary-parallel flow support the current Elevated threat for flash flooding. Current soil moisture saturation and derived flash-flood guidance values suggest areas in our south will have trouble if they pick up a quick 2 to 3 inches of rain. The threat for flash flooding will continue into tomorrow with the next impulse, so any rainfall tonight will be important to the evolving flood threat tomorrow. /NF/ Friday through Wednesday: An active weather pattern will continue on Friday as additional shortwaves traverse across the area, keeping the risk of severe weather and flash flooding in the CWA. A weak cold front remains on track to progress towards to the southeast region to help clear out the shortwave disturbances by Saturday evening. The extended period is expected to close out with a warming trend as a ridge amplifies over the area, bringing above-seasonal temperatures by mid-week. A low pressure center and weak cold front embedded in the longwave trough near TX will continue to proceed towards the southeast CONUS on Friday. Ahead of the frontal boundary, the shortwave disturbances are expected to interact with the moist airmass (dewpoints in the lower 70s) over the area. In addition to sufficient moisture: CAPE values near 3000 J/kg, bulk shear values of 50-60 kt, and lapse rates ranging from 6-7 C/km will help support organized convection and possible severe weather Friday evening. Damaging winds, hail, and tornadoes will be possible. The "Slight" risk is outlined in the HWO graphics. Along with severe weather, flash flooding continues to be of concern. PW values remain between 1.6-2.0in; however, IVT vectors have exceeded the 99th percentile in the latest NAEFS run. As a result, training thunderstorms will be possible, leading to flash flooding in areas that have already received rainfall. Rainfall totals have lowered from yesterday's model runs but 1 to near 4 inches of rainfall will be possible. Majority of the rainfall is expected along and south of I-20 where 2-4 inches of rain will be possible. Elsewhere, 1-2 inches of rainfall is expected. An "Elevated" risk for flash flooding remains for Friday evening. As the weak cold front exits the area Saturday evening, rain chances will begin decreasing from west to east. Some lingering rainfall will be possible post frontal passage but these showers aren't expected to pose a flooding threat. By Sunday, the area will begin to dry out as a ridge migrates over the area. The ridge is expected to amplify into the new week, bringing above-seasonal temperatures (highs in the lower 90s). Rain chances are expected to return to the area by the end and beyond the extended period. /SW/ && .AVIATION... (18Z TAFS) Issued at 132 PM CDT Thu May 16 2024 VFR conditions will prevail through a majority of the TAF period. By 3-6Z TAF conditions will lower to MVFR to brief IFR conditions as increasing chances for SHRA, TSRA and low cigs will impact TAF sites from west to east. Expect continued impacted MVFR conditions through the end of the TAF period as chances for showers and storms linger. In addition, it's worth noting that there are indications in the CAMs that a wake low could form behind the the stratiform rain tonight. Potential wind gusts of 30-40 Kts will be possible at southern TAF sites around 6Z if confidence increases./KP/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 65 83 68 84 / 80 90 50 50 Meridian 64 84 67 85 / 70 90 60 70 Vicksburg 65 82 68 86 / 90 70 40 40 Hattiesburg 68 85 70 85 / 80 80 60 70 Natchez 64 83 67 86 / 100 70 50 40 Greenville 67 81 67 84 / 80 70 40 30 Greenwood 67 80 67 83 / 80 80 50 40 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Flood Watch from 1 AM CDT Friday through Saturday morning for MSZ047>066-072>074. LA...Flood Watch from 1 AM CDT Friday through Saturday morning for LAZ015-016-023>026. AR...None. && $$ KP/SW/NF