Area Forecast Discussion
Issued by NWS Jackson, MS

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583 FXUS64 KJAN 301450 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 950 AM CDT Sun Jun 30 2024 ...New MESOSCALE UPDATE... .MESOSCALE UPDATE...
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Issued at 939 AM CDT Sun Jun 30 2024 Northerly flow has allowed for less ascent and cloudcover this morning compared to 24 hours ago, and so any precip has held off. This should allow temperatures to warm into the low to mid 90s, assuming convection holds off til afternoon, which most CAM guidance does, with most initiating by mid afternoon. With dewpoints holding in the upper 70s with spots of 80, will continue to carry heat headlines and messaging. Weak mid level lapse rates should serve to limit severity of storms, but as always conditions will be monitored through mesoanalysis./SAS/
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&& .DISCUSSION... Issued at 404 AM CDT Sun Jun 30 2024 Today and Tonight: Once again, dangerous heat will be the main concern for today as early morning global guidance continues to highlight upper ridging across much of the southeast CONUS. Afternoon highs will peak in the mid to upper 90s areawide with dewpoints climbing in the upper 70s. Several areas across the Delta could see dewpoints in the 80s. This combination will yield heat indices in the 105-115 deg range across our forecast area. For this reason, an excessive heat warning remains in effect until 8 pm this evening, including the Delta, our southeast Arkansas counties, and all of our northeast Louisiana parishes. Elsewhere, a heat advisory remains in effect mainly for areas along and east of the I-55 corridor. No changes have been made to the heat graphic for today and a "Significant" risk has been maintained where the excessive heat warning remains in effect. Hot and muggy conditions will persist today as early morning HRRR guidance holds off convection until later this afternoon, with the best rain chances across the Pine Belt. Global guidance shows a high pressure system moving east across the Ohio River Valley later this evening. At the same time, a weak cold front, located on the southern periphery of the aforementioned sfc high, will push south into the northern portions of our forecast area. Rain chances will still be possible along and south of the cold front later in the evening before diminishing heading into the overnight period. Expect nighttime temperatures to drop in the low to mid 70s areawide. /CR/ Monday through Saturday: Drier post-frontal air mass on Monday will be enough to keep rain chances mostly out of our forecast area. By the late afternoon, PWAT values should be 1.5 inches or less north of the Highway 84 corridor. The ridge pivoting overhead will still keep temperatures warm, so areas behind the front are looking at highs in the low 90s (normal for early July). In the frontal zone closer to the Gulf Coast, afternoon highs and increased humidity will result in heat index values in the 105 to 110 degree range. A Heat Advisory is likely to be issued for southern parts of the forecast area, but will let the Excessive Heat Warning today play out before issuing a follow-up product for tomorrow. As the front washes out, temps should quickly rebound for the rest of the week. Daily rain chances will be focused in the afternoon with peak heating and mainly in the south and southeast with possible sea breeze activity and better moisture availability. Flow trajectories around the high will bring drier air generally from the east through most of the period. Friday into the weekend, the ridge shifting farther east will allow for troughing to more influence the central and southern US. Another cold front moving into the region will likely bring another focus for rain during the weekend. We will also keep an eye toward the Tropics as several areas of interest in the Atlantic are monitored by the National Hurricane Center and as Hurricane Beryl moves westward toward the Caribbean. /NF/ && .AVIATION... (12Z TAFS) Issued at 618 AM CDT Sun Jun 30 2024 VFR ceilings will occur across central MS to start off the TAF period. Weather conditions will remain quiet through 17Z with mid to high clouds expected. By 18Z Sunday afternoon, convection will start to develop along the Hwy 84 corridor around this timeframe before becoming widespread around 19Z as the seabreeze slowly drifts north. Added VCTS and SHRA to most zones with a short period of MVFR to possible IFR ceilings for PIB, HBG, HKS, JAN from mid to late afternoon. Rain activity will continue into the evening. By 06Z Monday rain chances will come to an end with VFR ceilings prevailing across all TAF sites. VFR ceilings will occur through 07Z Monday. By 08Z Monday, ceilings will drop down to MVFR to potential IFR conditions as cloud cover increases across central MS. Ceilings will remain in MVFR status through 15Z Monday. By 16Z Monday, ceilings will start to improve to VFR status. /CR/ && .PRELIMINARY POINT TEMPS/POPS...
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Jackson 95 76 93 70 / 50 40 10 0 Meridian 96 73 94 68 / 60 40 10 0 Vicksburg 95 76 93 70 / 50 30 10 0 Hattiesburg 95 77 96 74 / 60 30 20 0 Natchez 95 76 93 72 / 40 30 20 0 Greenville 97 75 91 68 / 50 40 0 0 Greenwood 95 73 92 68 / 50 40 0 0
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&& .JAN WATCHES/WARNINGS/ADVISORIES... MS...Excessive Heat Warning until 8 PM CDT this evening for MSZ018- 019-025>027-034>036-040>042-047-053-059-060. Heat Advisory until 8 PM CDT this evening for MSZ028>033-037>039- 043>046-048>052-054>058-061>066-072>074. LA...Excessive Heat Warning until 8 PM CDT this evening for LAZ007>009-015-016-023>026. AR...Excessive Heat Warning until 8 PM CDT this evening for ARZ074- 075. && $$ CR/NF/CR