861 FXUS64 KJAN 090924 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 424 AM CDT Fri Aug 9 2019 .DISCUSSION... Today and Tonight: Weak shortwaves will continue to parade around the northern periphery of mid level ridge today with one of the more potent ones arriving over north MS during period of max heating. Local microburst composite parameter indicating decent chances in this same general area, as well. With upstream cold pool advancement appearing most favorable through this area, will keep the marginal severe risk going in the HWO. Otherwise, the slow eastward progression of the ridge center will mean another hot day in store. Local climatological data suggests mid 90s for highs today which seems reasonable given 850 mb temps around 20C. This with afternoon dewpoints remaining in the mid 70s will keep heat indices 105-110./GG/ Saturday through Tuesday: Oppressive and potentially dangerous heat will continue to escalate through the early portion of next week. A stout mid/upper ridge will be situated from the Red River Valley through the ArkLaTex on Saturday with a surface high centered over the Gulf. Despite the close proximity of the ridge, considerable low level moisture (PW progged to approach 2.5") will exist across the region and the area will be close to passing mid level NW flow disturbances. This will maintain good chances for rain on Saturday, particularly during the daytime instability period. Outside of the shielding influence of rain/clouds, heat indices may surpass 105F at times. Given uncertainties with respect to which areas will be impacted by clouds/rain on Saturday, we will not yet make a decision on extending the Heat Advisory into this period yet, but one may well be needed for at least a portion of the area. Sunday through Tuesday, the mid/upper ridge will begin building eastward, with the center becoming closer to our forecast area. Increasing thermal capping associated with the ridge will begin to limit precip coverage on these days, though rich low level moisture will persist and scattered diurnal convection will remain possible. With low level heights increasing, temperatures will also tick upward toward the upper 90s in many areas with a few triple digit readings not out of the question. Given the lingering low level moisture, heat indices will push further, into the 110-115F range in some areas. A Heat Advisory will almost certainly be needed, with an Excessive Heat Warning not out of the question for some portion of the area. We will continue to advertise a 'significant' threat for heat stress in our HWO/graphical products mainly west of I-55. Heat indices will be regulated to some extent by the presence of scattered convection, though most of this development will occur in the afternoons, allowing ample time for heat indices to rise earlier in the day. Wednesday and Thursday: Model agreement is somewhat better in a much-welcomed front approaching the area as we head into the latter portion of the week, though perhaps not reaching the area until after the current forecast period. While temps may still run near to slightly above normal ahead of this front and low level moisture will remain plentiful on Wednesday and Thursday, there will be an increase in rain chances, which will hopefully serve to provide greater relief from the heat. /DL/ && .AVIATION... 06Z TAF discussion: Patchy MVFR/IFR conditions in low clouds and fog early will give way to VFR conditions by mid morning. Isolated to scattered showers and thunderstorms will develop by noon and linger into the early evening. Where storms occur, a brief lowering of ceilings and visibilities can be expected./GG/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 94 76 92 76 / 43 20 57 18 Meridian 95 75 92 75 / 50 30 59 16 Vicksburg 94 77 93 77 / 31 14 48 16 Hattiesburg 95 76 94 75 / 40 26 58 19 Natchez 94 76 92 76 / 19 10 42 16 Greenville 92 76 92 77 / 39 26 55 12 Greenwood 90 76 90 76 / 54 30 60 15 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Heat Advisory until 7 PM CDT this evening for MSZ018-019-025>066- 072>074. LA...Heat Advisory until 7 PM CDT this evening for LAZ007>009-015-016- 023>026. AR...Heat Advisory until 7 PM CDT this evening for ARZ074-075. && $$