Area Forecast Discussion
Issued by NWS Jackson, MS
Issued by NWS Jackson, MS
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752 FXUS64 KJAN 231837 AAC AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 137 PM CDT Thu May 23 2024 ...New AVIATION... .MESOSCALE UPDATE... Issued at 1037 AM CDT Thu May 23 2024 Assessing the current environment and short-term forecast, a few things should be noted. First, the various high-res models will struggle in this environment as much of the forcing is driven by ongoing convection and cold pool dynamics. Additionally, the environment is partially affected by the last round of storms that blew through parts of the forecast area last night. Therefore, the latest mesoanalysis and trends in radar/satellite imagery are more important to anticipating how weather will evolve into this evening time frame. With west-to-east flow aloft associated with the jet stream, mean flow and deep-layer shear vectors are oriented to the east. Meanwhile the most unstable air is focused across east Texas and western Louisiana, with a gradient set up west to east across our area. This aligns with how we are seeing the remnants of this morning`s convection behave as it has rolled out of Arkansas. The eastern portions of that line are now propagating southward to favor the available instability, while the part of the line farther to the west (still in the unstable air) has now become aligned more perpendicular to the flow and is being steered eastward. This mess of convection remains capable of some brief damaging wind gusts and small hail, but expect it to run out of steam as storm segments run into each other and get cut off from the better instability back to the west. Visible satellite imagery shows a more diffuse outflow boundary to the west across northwest Louisiana, with cloud elements becoming more unstable and moving northward again. Farther southeast, daytime cumulus field can be seen advancing northward through southwest Mississippi. Dewpoints should recover into the lower and mid 70s as this air mass returns northward. Despite the varying solutions, most of the guidance does agree that convection should redevelop this afternoon and evening with daytime heating. The deep-layer shear and adequate instability will allow for some organized severe storm threat to develop, so will maintain the current hazardous weather outlook graphics. I did increase POPs and QPF some for today and tonight, as blended NBM guidance was washing out the various solutions. /NF/ && .DISCUSSION... Issued at 427 AM CDT Thu May 23 2024 Today through Tonight: An ongoing threat for severe will continue today before diminishing later this evening. Model consensus continues to highlight a 998 mb sfc low developing across the NW CONUS before shifting eastward towards southern Canada later this morning. As the sfc low shifts north towards Canada, broad longwave troughing will continue to dominate the western and central CONUS. Any disturbances that ripple out of this longwave trough will provide the support for diurnal activity to organize and propagate eastward across the forecast area through this evening. The Slight Risk area closer to the front (northwest of our CWA) has been extended further south in order to capture the severe potential across the Delta. The Marginal Risk (1 out of 5) has been extended further south in order to capture areas along and north of the I-20 corridor with the threat for damaging wind gusts and hail up to quarter size cannot be ruled out. In addition to the severe potential, there may be some potential for multiple storms to move across the area and produce locally heavy rainfall of 2 to 3 inches at times which could lead to minor runoff issues in poor drainage areas along with the potential for localized flash flooding in a couple of areas. The severe potential will start to diminish across the area as we head into overnight period with lingering showers and storms along and north of the Hwy 82 corridor. The combination of lingering showers and cloud cover will keep nighttime temperatures in the 70s across the area. /CR/ Friday through Wednesday:Come Friday morning we will still have a warm moist airmass over our region with PWATs around an inch and a half with upper 60s to lower 70s dew points. A nearly stacked low over the northern Plains will be lifting up into Ontario and leaving a trailing cold front to drift into northern Mississippi and stall. During the heat of the afternoon storms are expected to develop along and just ahead of the cold front and spread into our CWA. Isolated severe storms capable of damaging wind gusts and hail up to quarter size will be the main threats with the storms but a brief tornado or two cannot be ruled out. This activity is expected to wain during the evening with the loss of heating. The stalled front will still be across northern Mississippi Saturday but a little farther north. Isolated severe storms will again be possible with the same threats but over less of our CWA; mainly along and north of Highway 82 during the late afternoon and early evening. Sunday mid level ridging across our south will strengthen some while another weak low pressure system tracks east across the Plains and southern Great Lakes region. This low pressure system will try to drop a weak cold front back into northern Mississippi. There will be the potential for isolated severe storms across our north again. Saturday and Sunday across the southern half of moved out of the warned area.**!the area where greater insolation is expected due to the mid level ridge, temperatures will top out in the low to mid 90s resulting in peak heat index values around 100F. Severe storm potential across the north along with heat and humidity across the south will continue Monday but, a more potent low pressure system tracking east across the Great Lakes region Monday night and Tuesday looks to bring some relief Tuesday through Wednesday as a clearing cold front is expected. PWATs are expected to be knocked back below one inch with lower 60 dew points by Tuesday morning. /22/ && .AVIATION... (18Z TAFS) Issued at 133 PM CDT Thu May 23 2024 Better chances for impacts from SHRA and TSRA will be at KGLH, KGWO, and KGTR through the TAF period, however the chance cannot entirely be ruled out at the other TAF sites. Low stratus apart from areas of rain overnight will likely produce MVFR to IFR ceilings at the TAF sites, with gradual mixing and lifting to VFR conditions after 15Z Friday. /NF/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 89 71 91 72 / 20 40 10 10 Meridian 89 70 91 71 / 10 20 10 10 Vicksburg 90 72 92 72 / 40 50 10 10 Hattiesburg 91 72 92 72 / 0 10 10 0 Natchez 90 73 91 72 / 20 30 10 0 Greenville 87 72 90 72 / 70 70 10 40 Greenwood 86 70 90 72 / 70 60 20 30 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ CR/22/NF