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080 FXUS64 KLIX 022047AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA347 PM CDT Sun Jun 2 2024...New SHORT TERM, LONG TERM, AVIATION, MARINE....SHORT TERM...(This evening through Monday night)Issued at 254 PM CDT Sun Jun 2 2024No significant change in the overall synoptic level pattern isexpected through tomorrow night. The region will remain embeddedwithin a zonal flow regime, and a series of weak shortwave troughswill slide through the Lower Mississippi Valley. The first ofthese troughs is currently pushing through the region, and thishas provided enough forcing to support convective developmentalong pre-existing mesoscale boundaries throughout the day. Thisconvection is largely driven by increased instability associatedwith daytime heating, and is expected to dissipate through the midto late evening hours as temperatures cool back into the 70s.Another shortwave trough axis will slide through the areatomorrow, and this will once again provide the needed forcing tosupport scattered convective development as temperatures warm backinto the mid 80s during the afternoon hours. PWATS will remainhigh at between 1.75 and 2 inches, so locally heavy rainfall willcontinue to be a concern. Overall, have went PoP values in the 40to 60 percent chance range for tomorrow afternoon.&&.LONG TERM...(Tuesday through Saturday night)Issued at 254 PM CDT Sun Jun 2 2024Tuesday will be a very typical early June day across the forecastarea. Zonal flow will remain in place aloft and widely scatteredconvection will develop along weak mesoscale boundaries like theseabreeze and outflow boundaries from previous convection astemperatures warm into the upper 80s and lower 90s. Thunderstormactivity will peak in the mid to late afternoon hours when SBCAPEvalues are highest at around 2500 to 3000 J/KG. These storms willbe short-lived as updrafts become cold pool dominated and collapsein generally an hour or less, and there will be a risk of briefheavy downpours producing an inch or two rain with thesethunderstorms. The strongest updrafts could reach into a drierairmass aloft, and this dry air entrainment could lead to a fewstorms producing locally higher wind gusts. Overall, have wentwith PoP that is right in line with climatology at around 30percent for Tuesday afternoon. A pattern change is then expected to take shape on Wednesday as avery strong northern stream trough deepens in the Great Lakesstates. In advance of this trough, a shortwave ridge over Texasand western Gulf will extend more toward the forecast area, andthis will help to cap off most convective potential on Wednesday.This will be due to the stronger subsidence aloft not only dryingbut also warming the mid-levels enough to produce a strong mid-level temperature inversion. Any updrafts will struggle to breakthrough this layer of warmer air, and this will limit rain chancesto a few showers during the afternoon hours over more inland areaswhere afternoon heating is greatest. Speaking of heating,temperatures will be much warmer in the lower 90s over inlandareas and the upper 80s along the coast.By Thursday, the northern stream trough will have deepened enoughto drive a frontal boundary through the forecast area. This frontwill tap into a moderately unstable airmass as noted by SBCAPEvalues of 1500 to 2000 J/KG to produce a convective line along thefront. There could be some stronger wind gusts with the line as itmoves through. This is supported by high DCAPE values of 1000 to1200 J/KG and steep low level lapse rates. Temperatures will alsobe quite warm with highs climbing into the lower to even middle90s in advance of the cold front. The front will clear theoffshore waters Thursday night, and the convective threat shoulddiminish.The area should then find itself embedded with deep layernortherly flow on both Friday and Saturday as a strong upper levelridge dominates the Plains and the deep trough dominates theeastern seaboard. This northerly flow pattern can be tricky duringthe Summer months, as temperatures quickly climb into the low tomid 90s each afternoon and a collision between the seabreeze andthis northerly flow ensues. This collision, depending on moistureand instability in the low to mid-levels could support isolatedstrong to occasionally severe thunderstorms. A review of modelsounding data indicates that Friday is the more likely of the twodays for this to occur, and have included a low PoP of 20 percentin the forecast to reflect this convective risk. If storms doform, and the updrafts become sufficiently deep, the risk ofdamaging winds and heavy rainfall will increase substantially.Away from the isolated convection, hot, sunny, and humid weathercan be expected both Friday and Saturday. &&.AVIATION...(18Z TAFS)Issued at 254 PM CDT Sun Jun 2 2024A thunderstorm is currently in the vicinity of NEW and may impactthe terminal over the next hour. Given this threat, have includeda TEMPO group from 18z to 19z that includes a mention of gustywinds, thunderstorms, and MVFR ceilings and visibilities. Asimilar threat exists at all of the other terminals through around00z as the atmosphere remain moist and unstable, but thunderstormprobabilities are too low to include as a prevailing or TEMPO group. Instead, have included periods generally ranging from 2 to4 hours of prevailing rain shower activity with vicinitythunderstorms between 19z and 00z at all of the terminals. Ceilings will range from 2000 to 3000 feet over this period. If a thunderstorm is expected to directly impact a terminal, an amendment with TEMPO group will be added. After 00z, the thunderstorm activity will wane with the loss of daytime heating. Prevailing MVFR and VFR conditions are expected from 00z through 18z tomorrow at nearly all of the terminals. Only MCB could see a brief period of IFR ceilings and MVFR visibilities develop beneath a weak low level inversion between 10z and 13z tomorrow morning.&&.MARINE...Issued at 254 PM CDT Sun Jun 2 2024No significant weather concerns are anticipated in the coastalwaters through the end of the week. Winds will initially remainout of the south and southeast at around 10 knots through Wednesday and seas will remain in the 1 to 2 feet range. OnThursday, a weak front will slip through the waters, and windswill briefly turn northerly at 10 to 15 knots on Friday.Otherwise, the only concern through the week will be the risk oflocally higher winds and waves near any thunderstorms that formthis week. It is safe to say that we are moving toward a very typical Summer pattern this week. &&.PRELIMINARY POINT TEMPS/POPS...MCB 68 87 71 89 / 20 50 50 30 BTR 71 88 73 90 / 40 40 30 20 ASD 71 88 74 89 / 30 20 20 30 MSY 74 87 76 88 / 40 30 20 30 GPT 74 86 76 86 / 20 20 20 30 PQL 72 86 74 86 / 20 20 20 30 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...None.GM...None.MS...None.GM...None.&&$$SHORT TERM...PGLONG TERM....PGAVIATION...PGMARINE...PG
