Area Forecast Discussion
Issued by NWS Jackson, MS
Issued by NWS Jackson, MS
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059 FXUS64 KJAN 091949 AAC AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 249 PM CDT Sun Jun 9 2024 ...New AVIATION... .MESOSCALE UPDATE... Issued at 1023 AM CDT Sun Jun 9 2024 An upper-lvl/sfc ridge is expected to shift southward, allowing a frontal boundary to progress towards the area. Majority of the convective activity seen on GOES-16 is found along and ahead of a frontal boundary. Ahead of the frontal boundary, westerly/southwesterly flow will push additional moist air into the region. As dewpoints reach the lower 70s, humidity is expected to increase. Expect afternoon temperatures to reach the mid 90s. With temperatures in the mid 90s and increasing humidity, heat indices near 105 degrees will be possible. HWO graphics will continue to advertise the heat threat. In addition to increasing dewpoints, anomalous SBCAPE/DCAPE values and deep-layer shear over the region will help promote some organized convection, resulting in possible strong to severe storms this afternoon and into this evening. After modifying the 12Z morning sounding, combined with the afternoon heat and humidity, afternoon microburst potential in the Hwy 82 corridor is in the 7-9 range, with supports likely potential for severe storms. SPC added a "Slight" risk to areas across HWY 82 corridor and expanded the "Marginal" risk to areas as far south as I-20. Main concerns remain damaging wind gusts of 60-70mph and quarter size hail or potentially larger, as efficient hail growth is possible due to large CAPE in the hail growth region of -10 to -30 degree C. HWO graphics are updated for the and severe weather/heat risk and updates are out. /SW/ && .DISCUSSION... Issued at 429 AM CDT Sun Jun 9 2024 Today and Tonight: A surface high which has been over the area will continue to weaken and shift southward as a cold front arrives from the north today. Upper-level riding farther south over the Gulf Coast will suppress rain chances through the day, but gradually falling heights across the Mid-South down into northern Mississippi will allow for some convection north of Interstate 20 by the afternoon. Pooled moisture along the cold front and heating to the south should result in about 3000-4000 J/kg of SBCAPE in northern MS and southern AR. Forecast soundings show little to no inhibition during peak heating and DCAPE values in the 1500-1600 range. Any disturbance such as outflow from storms to the north could trigger deep convection. Deep-layer westerly wind shear values will be around 25-30 kts in that area, so enough flow to help with some organization of storms if they should develop. Various high-res guidance members provide such a solution, with most of the storm threat pushing east into Alabama by late evening/early tonight. Given the strong heating south of the front and modest flow aloft, damaging wind gusts will be the primary hazard with any storms though hail is possible as well. Additional chances for some showers or storms will continue into the overnight as the main front pushes southward. Heating and moisture south of the front will also result in some dangerous heat concerns across the forecast area today. Guidance has trended higher on the dew points for today, with less deep mixing of dry air compared to yesterday. Low 70s dew points and afternoon temps pushing the mid 90s should result in peak heat index values near 105 degrees, plus or minus. Expanded the Limited threat heat outlook to cover the forecast area, but the best chances to hit 105 currently appear to be focused from around Jackson/Vicksburg and northward into the Delta. /NF/ Monday through Saturday: Monday, northerly flow should continue as the cold front continues to slowly pass south/southeast through the area. We can expect to see some lingering scattered storms across and ahead of the frontal boundary. Storm coverage will be confined and storms are expected to be largely sub-severe thus there will be no outlooks for Monday. Behind the front Tuesday-Wednesday, drier and cooler air will advect into the north and high temperatures will dip slightly into the mid to high 80s for most of the area with regions of the Pine Belt remaining in the low 90s. Heat stress will be much less concerning with only areas of the Pine Belt having max heat indices nearing 100 degrees. Rain chances will continue through the week for the southern half of the CWA as a broad area of low pressure over the Gulf of Mexico feeds in low level moisture to the area. Storm coverage looks to be more isolated to scattered across the south and southeast. The end of the long term looks to be very uncertain as guidance has struggled to produce any persistent weather pattern but ridging across the southeastern states looks to be the best solution. This will help to keep the disturbance into the Gulf of Mexico through Saturday. && .AVIATION... (18Z TAFS) Issued at 249 PM CDT Sun Jun 9 2024 VFR flight conditions and westerly/southwesterly winds near 5 mph are expected to start the TAF period. Showers and thunderstorms will be possible in the afternoon and evening hours at northern TAF sites as a cold front moves into the area. 40-50 kt gusts and 1.0 in hail with brief reduction of ceilings and visibility will be possible at sites receiving these storms. MVFR flight conditions will be possible at TAF sites north of I-20 around 07Z Monday for as the front migrates through the area, returning to VFR conditions after 13Z Monday. Remaining TAF sites are expected to remain at VFR through the end of the period. /SW/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 71 86 65 87 / 10 20 0 10 Meridian 71 88 64 88 / 30 20 0 0 Vicksburg 71 86 65 87 / 10 20 0 10 Hattiesburg 73 92 68 91 / 10 50 10 10 Natchez 70 88 68 88 / 0 30 0 10 Greenville 70 85 64 86 / 30 20 0 0 Greenwood 69 85 63 86 / 40 20 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ NF/KP/SW