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139 FXUS64 KLIX 260852AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA352 AM CDT Wed Jun 26 2024...New SHORT TERM, LONG TERM, MARINE....SHORT TERM...(Today through Thursday)Issued at 339 AM CDT Wed Jun 26 2024Upper ridging centered over the Four Corners area early thismorning. Shortwaves, or at least MCV's, were noted near KansasCity and over southeast Oklahoma. A few isolated showers overPlaquemines Parish and over the Gulf, but no indications oflightning at this point. Early morning temperatures ranged fromthe mid 70s to lower 80s across the area with dew points primarilyin the mid and upper 70s. Fairly wet sounding in place withprecipitable water values on the 00z LIX and JAN soundings in the1.9 to 2.0 inch range, which is generally above the 75thpercentile for late June. Issues for the first 36 hours of the forecast are twofold, thethreat of thunderstorms and heat stress conditions. Whileshortwave energy is approaching from the northwest, it's ratherquestionable at this point whether organized convection developsprior to mid to late afternoon. Most of the convection allowingmesoscale models don't develop much in the way of thunderstormsprior to 21z this afternoon, with actually the better chance oforganized convection overnight tonight. Unfortunately, there'slittle agreement as to the area to be impacted, with solutionsranging from Alabama to east Texas. Considering that we can seeseparate impulses upstream this morning, can't entirely rule outclusters east and west of the area, and little over the localarea. Of course, we also have the issue of southeastwardpropagating cold pools generally arriving quicker than themesoscale models depict. The forecast scenario we'll predicate this morning's forecast onis for only isolated to widely scattered areal coverage ofthunderstorms during the midday to late afternoon hours today.Organized convection will be possible overnight with shortwaveenergy moving into the area, and we can't rule out a strong to severe storm cluster depending on if a cold pool develops and where it moves. Redevelopment of showers and/or storms on remnant outflows is anticipated tomorrow afternoon, but am a bit concernedthat current probabilities of precipitation for Thursday are somewhat overdone. However, considering decent agreement with neighboring offices, won't make changes for now.With any organized convection not expected prior to earlyafternoon, that should allow sufficient time for temperatures toget into the lower and middle 90s. Combined with dew points in themid and upper 70s, that will produce heat indices in the 105 to110F range for a good segment of the area, at least briefly. It'sa borderline advisory situation, and have collaborated a HeatAdvisory for the same areas as yesterday for the late morning andafternoon hours today. If organized convection develops earlierthan expected, the advisory may be cancelled prior to expiration.Between lingering cloud cover from overnight convection and thepotential for redevelopment tomorrow afternoon, high temperaturesare expected to be several degrees cooler for much of the area,and do not anticipate a need for advisories tomorrow.&&.LONG TERM...(Thursday night through Tuesday)Issued at 339 AM CDT Wed Jun 26 2024For at least Friday through the weekend, the Four Corners upper ridge is expected to shift eastward and elongate east/west somewhere near Interstate 20 to our north. Exactly where thatridge sets up could be the difference between scattered stormseach day, or a dry and hot weekend. Forecast 500 mb temperaturesFriday are expected to be in the -2C to -4C range from north tosouth with 700 mb temperatures near or above +10C, and only a degree or two colder Saturday/Sunday. Usually, those mid level temperatures Friday are sufficient to shut down convective development, but most all guidance is showing at least some storm development.Wouldn't be surprised at all to see later guidance back down rainchances for the weekend and into early next week, which would probably put us in Heat Advisory range again. NBM deterministichighs track with the warmer of the global model guidance fromFriday onward, but overnight lows look to be a degree or two toocool. &&.AVIATION...(06Z TAFS)Issued at 1158 PM CDT Tue Jun 25 2024VFR conditions prevail at all area airports and will persist through the forecast period for most area airports. KMCB will lower ceilings to IFR and maybe even LIFR conditions tomorrow morning, and these conditions will persist for MCB for the morning hours. Vicinity showers and storms will be expected near all area airports tomorrow afternoon and evening. Winds shifts greater than 30 degrees will be possible at coastal aviation sites, like KNEW, KMSY, and KGPT tomorrow morning. MSW&&.MARINE...Issued at 339 AM CDT Wed Jun 26 2024On the large scale, weak pressure gradients should lead to lightwind fields for much of the period, with the exception of theusual diurnal increase over the sounds and waters east of the MSdelta each evening. Thunderstorms will be more of a concern,especially during the overnight and morning hours. Considering thevery moist airmass and light low level winds, there will bepotential for slow moving or nearly stationary waterspouts attimes. &&.PRELIMINARY POINT TEMPS/POPS...MCB 92 73 89 73 / 50 60 80 20 BTR 96 78 93 77 / 50 40 80 20 ASD 94 76 91 76 / 50 40 90 40 MSY 94 78 91 78 / 50 40 90 30 GPT 94 75 91 76 / 40 50 80 50 PQL 96 76 93 75 / 40 50 70 50 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...Heat Advisory from 11 AM this morning to 7 PM CDT this evening for LAZ034>037-039-046>048-056>060-064-065-071-076>090.GM...None.MS...Heat Advisory from 11 AM this morning to 7 PM CDT this evening for MSZ068>071-077-083>088.GM...None.&&$$SHORT TERM...RWLONG TERM....RWAVIATION...MSWMARINE...RW
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Topic: [Alert]LIX issues Area Forecast Discussion (AFD) at Jun 26, 3:52 AM CDT ...New SHORT TERM, LONG TERM, MARINE... (Read 332 times)
