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748 FXUS64 KLIX 201843AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA143 PM CDT Sun Jul 20 2025...New SHORT TERM, LONG TERM, AVIATION, MARINE....SHORT TERM...(This evening through Monday night)Issued at 135 PM CDT Sun Jul 20 2025The weak upper low that was over the local area at the end of lastweek is now over Texas with mid level ridging off the coast ofPlaquemines Parish. At the surface, high pressure is centered overthe Gulf somewhere south of Pensacola. Scattered cumulus werenoted on satellite, and there may be one or two showers out there,but the overwhelming majority of the area is, and will, be drythis afternoon. Temperatures at early afternoon range from theupper 80s to mid 90s with heat index values around 105. The upper ridge will continue to drift west and northwest over thenext 36 hours, and cover most of the lower Mississippi RiverValley by tomorrow night. Cannot entirely rule out isolated stormsthis afternoon and tomorrow afternoon, but most areas will remaindry, and any storms that do develop should dissipate by sunset. Main concern is going to be the heat. While conditions areborderline for an advisory today, high temperatures tomorrow lookto be in the mid 90s areawide, and a few spots could reach 97F orso. Dew points look to be in the same general range as today, midand upper 70s, so heat index values could actually be a touchhigher tomorrow. Have already pre-emptively issued a Heat Advisoryfor tomorrow for all of the area except the lower portions of thesoutheast Louisiana coastal parishes. The same areas as today'sadvisory. &&.LONG TERM...(Tuesday through Saturday night)Issued at 135 PM CDT Sun Jul 20 2025The upper ridge will drift northward Tuesday and be centered nearMemphis Tuesday, before moving eastward later in the week. Thiswill allow an easterly wave to move across the northern GulfWednesday and Thursday. A northern stream shortwave could push afrontal boundary about as far south as Interstate 20 next weekend. Similar to Monday, any thunderstorm threat will remain veryisolated, with most areas remaining dry. If there is a focus forconvection on Tuesday, it would be lake/sea breeze boundaries. High temperatures Tuesday could actually be a degree or two higherthan tomorrow, with some guidance indicating upper 90s for highs.With a northerly component to surface winds on Tuesday, it is oneof those situations where the "hot spot" could actually the Pearland Pascagoula River Basins (Bogalusa, Slidell, Mississippi coastal cities) if the sea breeze kicks in late or not at all andno storms develop. In fact the MAVPQL (GFS based MOS for Pascagoula) gives 101 for Tuesday. Heat Advisories almost certain to be issued for Tuesday, and later shifts may need to consider anExtreme Heat Warning for portions of the area. As the easterly wave moves across the northern Gulf Wednesday andThursday, moisture levels will again be on the increase withprecipitable water values jumping from the 1.5 to 1.7 inch rangeTuesday to well in excess of 2 inches by late Wednesday afternooninto Thursday. Still some question as to how quickly the moisturespreads in on Wednesday, and how far north. Convective initiationmay hold off until late afternoon, which may necessitate a Heat Advisory for portions or most of the area.Thursday into next weekend will likely see daily development ofshowers and thunderstorms across much of the area. The additionalcloud cover and precipitation should hold high temperatures much closer to "normal" for late July, while overnight lows will be inthe mid and upper 70s.&&.AVIATION...(18Z TAFS)Issued at 135 PM CDT Sun Jul 20 2025Only very isolated TSRA so far this afternoon, and threat was toolow to mention in most terminals, other than VCTS at KHUM. Won't rule out 1 or 2 amendments this afternoon. Overnight should seeVFR conditions, and don't expect a repeat from this morning of very low conditions at KMCB. Cumulus development tomorrow shouldbe even less than today. &&.MARINE...Issued at 135 PM CDT Sun Jul 20 2025Main concerns for marine operations this week will be the threatof thunderstorms, as the general pressure gradient is expected toremain rather weak. Thunderstorm development is expected to remainfairly limited over the local waters until about Wednesday, whenareal coverage increases significantly. The second half of theweek will see multiple rounds of storms that will be capable ofproducing locally higher winds and seas.&&.PRELIMINARY POINT TEMPS/POPS...MCB 73 95 73 96 / 0 0 0 10 BTR 76 94 75 95 / 0 10 0 10 ASD 75 94 75 96 / 10 10 0 20 MSY 78 94 78 96 / 10 20 0 20 GPT 77 94 78 96 / 0 10 0 20 PQL 76 95 75 97 / 0 10 10 30 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...Heat Advisory until 7 PM CDT this evening for LAZ034>037-039- 046>048-056>060-064-065-071-076>090. Heat Advisory from 10 AM to 7 PM CDT Monday for LAZ034>037-039- 046>048-056>060-064-065-071-076>090.GM...None.MS...Heat Advisory until 7 PM CDT this evening for MSZ068>071-077- 083>088. Heat Advisory from 10 AM to 7 PM CDT Monday for MSZ068>071-077- 083>088.GM...None.&&$$SHORT TERM...RWLONG TERM....RWAVIATION...RWMARINE...RW