Area Forecast Discussion
Issued by NWS Jackson, MS
Issued by NWS Jackson, MS
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857 FXUS64 KJAN 041055 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 555 AM CDT Thu Jul 4 2024 ...New AVIATION... .DISCUSSION... Issued at 322 AM CDT Thu Jul 4 2024 Today and Tonight: Happy Independence Day, ArkLaMiss! Today won`t be very independent of the week it resides in, however, with hot and humid conditions continuing. One silver lining to that grey cloud, however, is... well, grey clouds. As increasing depth of the low level moisture continues amid consistent southerly flow and 500 mb heights falling from around 594-996 dam to the 592-594 dam range, we should see a bit more shower and storm coverage with the best chances across southern Mississippi where some afternoon seabreeze influence could offer additional lift. The rain chances are unlikely to cool the area off too much though and the only noticeable difference may be from southeast, where the best rain chances reside, to the northwest where lowest chances are expected. This will likely mean that southern Mississippi is slightly less oppressively hot compared to the north where heat indices are likely to reach 110-120 F compared to "only" 106-110 F further south. Excessive heat warnings and heat advisories delineate these areas and the lack of overnight relief as lows this morning (and yesterday morning..) hang out around 80 F will mean that the heat is especially dangerous. Greenville, for example, recorded max heat indices around 109 F Tuesday, 120 F Wednesday, and will likely see >110 F again today. For that reason, and especially for the Delta but area wide too, extra caution should be taken when outdoors particularly from mid morning into the early evening as heat stroke will be likely with prolonged activity. Temperatures will be slow to fall tonight with overnight lows again in the upper 70s F to near 80 F. Exceptions will be in those lucky cooler spots that see evening rain showers where temperatures likely settle into the middle 70s. In those areas, however, patchy fog will be likely late tomorrow night amid weak winds and dewpoints in the middle 70s F alongside those temperatures. /86/ Friday through next Wednesday: Most guidance indicate a small shift in the upper level pattern as westerlies are forecast to dip farther south and suppress the subtropical ridge. Overall, this should help to reduce heat stress and increase convective rainfall coverage over the forecast area. A cold front is expected to move into northern portions of the area Friday. As the front interacts with tropical-like moisture during peak heating, we should see considerable shower/storm coverage, especially over central/eastern MS. With mid level flow up to about 20kt, multicell storm line segments seem plausible, which may help to increase storm organization and wind gust potential. It appears the very humid boundary layer will heat up significantly ahead of the front, and have therefore expanded the elevated threat to include the entire area. Going through the weekend, greater moisture convergence and associated rain chances will be suppressed and confined mainly to southern portions of the forecast. Likewise, reduced boundary layer humidity will help to limit heat stress to more tolerable levels. Looking ahead to early/mid next week, while Hurricane Beryl is not expected to have a direct impact on the Lower Mississippi Valley region, there is a good bit of uncertainty on how the system will interact with the upper level pattern. It is possible that tropical moisture will help to enhance rainfall coverage, and we`ll be monitoring that potential. Otherwise, fairly typical summertime weather is forecast with diurnally driven convective rainfall. /EC/ && .AVIATION... (12Z TAFS) Issued at 551 AM CDT Thu Jul 4 2024 High overnight humidity has allowed intermittent low ceilings and visibility to MVFR/IFR to develop across central and southern sites early this morning. After 14z, prevailing VFR conditions are expected with increasing SHRA/TSRA coverage after 19z for all sites. Southerly, generally light winds will prevail through the period. /86/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 94 77 92 74 / 60 20 80 70 Meridian 94 76 93 73 / 70 20 80 70 Vicksburg 95 78 92 73 / 40 20 70 60 Hattiesburg 94 77 94 76 / 70 30 80 70 Natchez 93 77 92 73 / 40 10 70 60 Greenville 97 78 92 73 / 40 40 60 50 Greenwood 96 77 91 71 / 40 40 70 60 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Excessive Heat Warning from 10 AM this morning to 8 PM CDT this evening for MSZ018-019-025>030-032-034>037-040>043-047-048- 053-054-059-060. Heat Advisory from 10 AM this morning to 8 PM CDT this evening for MSZ031-033-038-039-044>046-049>052-055>058-061>066- 072>074. LA...Excessive Heat Warning from 10 AM this morning to 8 PM CDT this evening for LAZ007>009-015-016-023>026. AR...Excessive Heat Warning from 10 AM this morning to 8 PM CDT this evening for ARZ074-075. && $$ LP/EC/LP