Area Forecast Discussion
Issued by NWS Jackson, MS
Issued by NWS Jackson, MS
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091 FXUS64 KJAN 081156 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 656 AM CDT Wed May 8 2024 ...New AVIATION... .DISCUSSION... Issued at 501 AM CDT Wed May 8 2024 Today through tonight: After a hot day in which temperatures are expected to reach ~90 F over much of the forecast area, we should see the threat for severe weather increase late tonight. Subsidence associated with anticyclonic flow aloft will maintain a capping inversion over the forecast area today, and this will help keep thunderstorm chances to a minimum through this evening in spite of the hot and humid surface conditions. While isolated discrete storms could manage to develop during peak heating near the Highway 82 corridor, where ML CAPE will likely exceed 3000 j/kg, the threat for any organized storms will remain well north of the area until the cold front and associated convective system begin to shift southward late tonight. The combination of very unstable air and moderately strong deep layer shear will help to maintain a potential MCS as it shifts south, but the persistent ridge over the forecast area will tend to deflect greater forcing and slow the system progression down while veering the lower level flow. So will maintain the slight/marginal risks over northwest portions of the area and continue to emphasize damaging straight line/hail potential over tornado threats. The overall severe weather threat should be diminished as we approach daybreak Thursday morning. /EC/ Thursday through Thursday Night: A more significant severe weather threat may evolve late afternoon into the overnight. Most models indicate shortwave energy digging southward from the upper midwest will help to flatten the ridge and allow the cold front to shift closer to the I-20 corridor by late in the day. During the day, steep lapse rates and strong heating will make for a very unstable airmass with ML CAPE approaching 4000 j/kg, but the lack of forcing combined with a capping inversion will keep the potential for deep convection relatively low. The potential for strong to severe storms will begin to pick up during the evening (starting a little after 5pm) as greater ascent in the mid levels interacts with the stalled frontal boundary. This is when forecast confidence diminishes due to increased spread in the guidance concerning the convective evolution. While storms will likely develop well to the west over eastern TX initially, determining how they organize and where they go from there is a challenge. It appears the most probable scenario will follow that of the consistent GFS, which indicates the potential for an intense linear convective moving west to east across our forecast area with damaging wind gusts up to 70 mph and hail up to golf ball size being the primary concerns with these storms. The ceiling is relatively high concerning the potential severity of the late Thursday/Thu night convective system given the extreme thermodynamic parameters combined with strong deep layer shear, but in terms of probability, there is a good bit of spread still among the guidance in the placement/timing, and will maintain a slight risk in the outlook for now. As the event gets closer in time and guidance hopefully come into more agreement, then an increase in risk level will be likely for portions of the forecast area, especially for locations along/south of the I-20 corridor. In addition to the severe potential, there may be some potential for multiple storms to move across the area and produce locally heavy rainfall at times which could lead to minor runoff issues in poor drainage areas. We will continue to monitor trends associated with this system and will provide updates as they become available. Friday through Tuesday: Any thunderstorm chances will come to an end Friday as the frontal boundary surges further south out of our forecast area. Heading into the weekend, a 1020mb sfc high will develop in the ArkLaTex region before slowly pushing east towards our CWA. This will allow for quiet weather to settle across the south with cooler-than-normal temperatures expected. Rain chances will return to the area on Monday and Monday as future guidance hints at another low pressure pressure system developing across the Central Plains. /CR/EC/ && .AVIATION... (12Z TAFS) Issued at 650 AM CDT Wed May 8 2024 Persistent southerly flow will continue to drive the cycle of late night/morning stratus development during this forecast period. Expect MVFR category ceilings for the most part early this morning. As has been the case, mixing will lead to improvement during the mid/late morning and VFR conditions along with gusty southerly surface wind should prevail during the afternoon and evening, then expect MVFR category stratus to redevelop by late this evening. Any significant TSRA chances should hold off until late tonight at northern sites. /EC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 90 72 88 65 / 10 30 40 60 Meridian 91 71 89 64 / 10 30 50 60 Vicksburg 90 72 89 65 / 10 30 20 60 Hattiesburg 92 73 91 68 / 10 20 30 60 Natchez 90 72 91 64 / 10 20 20 60 Greenville 89 72 87 64 / 10 60 30 40 Greenwood 89 71 87 63 / 20 70 40 40 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ EC/CR/EC