Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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801 FXUS64 KLIX 030513 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1213 AM CDT Mon Jun 3 2024 ...New AVIATION... .UPDATE... Issued at 752 PM CDT Sun Jun 2 2024 Quick update to increase PoPs across the northwest around and after midnight. MCS coming southeast out of OK and northeast TX will maintain itself into northwest LA. CAMs are absolutely struggling with this feature again and have been so for the past few weeks. Looking at the current mesoscale features the theta e ridge is draped from SW to NE across northwest LA while the best instability is draped more west to east from central TX and running east just south of I-20. This would suggest that the MCS should get through northwestern LA then begin to weaken as it moves into central LA and towards swMS. Weaker mid lvl flow over seLA and swMS along with weaker 0-6km bulk shear and even weak upper lvl confluence all suggest steady weakening as this MCS approaches the area. That said still anticipate the MCS will get into northwestern zones but much much weaker than what is currently happening to the northwest. /CAB/ && .SHORT TERM... (This evening through Monday night) Issued at 254 PM CDT Sun Jun 2 2024 No significant change in the overall synoptic level pattern is expected through tomorrow night. The region will remain embedded within a zonal flow regime, and a series of weak shortwave troughs will slide through the Lower Mississippi Valley. The first of these troughs is currently pushing through the region, and this has provided enough forcing to support convective development along pre-existing mesoscale boundaries throughout the day. This convection is largely driven by increased instability associated with daytime heating, and is expected to dissipate through the mid to late evening hours as temperatures cool back into the 70s. Another shortwave trough axis will slide through the area tomorrow, and this will once again provide the needed forcing to support scattered convective development as temperatures warm back into the mid 80s during the afternoon hours. PWATS will remain high at between 1.75 and 2 inches, so locally heavy rainfall will continue to be a concern. Overall, have went PoP values in the 40 to 60 percent chance range for tomorrow afternoon. && .LONG TERM... (Tuesday through Saturday night) Issued at 254 PM CDT Sun Jun 2 2024 Tuesday will be a very typical early June day across the forecast area. Zonal flow will remain in place aloft and widely scattered convection will develop along weak mesoscale boundaries like the seabreeze and outflow boundaries from previous convection as temperatures warm into the upper 80s and lower 90s. Thunderstorm activity will peak in the mid to late afternoon hours when SBCAPE values are highest at around 2500 to 3000 J/KG. These storms will be short-lived as updrafts become cold pool dominated and collapse in generally an hour or less, and there will be a risk of brief heavy downpours producing an inch or two rain with these thunderstorms. The strongest updrafts could reach into a drier airmass aloft, and this dry air entrainment could lead to a few storms producing locally higher wind gusts. Overall, have went with PoP that is right in line with climatology at around 30 percent for Tuesday afternoon. A pattern change is then expected to take shape on Wednesday as a very strong northern stream trough deepens in the Great Lakes states. In advance of this trough, a shortwave ridge over Texas and western Gulf will extend more toward the forecast area, and this will help to cap off most convective potential on Wednesday. This will be due to the stronger subsidence aloft not only drying but also warming the mid-levels enough to produce a strong mid- level temperature inversion. Any updrafts will struggle to break through this layer of warmer air, and this will limit rain chances to a few showers during the afternoon hours over more inland areas where afternoon heating is greatest. Speaking of heating, temperatures will be much warmer in the lower 90s over inland areas and the upper 80s along the coast. By Thursday, the northern stream trough will have deepened enough to drive a frontal boundary through the forecast area. This front will tap into a moderately unstable airmass as noted by SBCAPE values of 1500 to 2000 J/KG to produce a convective line along the front. There could be some stronger wind gusts with the line as it moves through. This is supported by high DCAPE values of 1000 to 1200 J/KG and steep low level lapse rates. Temperatures will also be quite warm with highs climbing into the lower to even middle 90s in advance of the cold front. The front will clear the offshore waters Thursday night, and the convective threat should diminish. The area should then find itself embedded with deep layer northerly flow on both Friday and Saturday as a strong upper level ridge dominates the Plains and the deep trough dominates the eastern seaboard. This northerly flow pattern can be tricky during the Summer months, as temperatures quickly climb into the low to mid 90s each afternoon and a collision between the seabreeze and this northerly flow ensues. This collision, depending on moisture and instability in the low to mid-levels could support isolated strong to occasionally severe thunderstorms. A review of model sounding data indicates that Friday is the more likely of the two days for this to occur, and have included a low PoP of 20 percent in the forecast to reflect this convective risk. If storms do form, and the updrafts become sufficiently deep, the risk of damaging winds and heavy rainfall will increase substantially. Away from the isolated convection, hot, sunny, and humid weather can be expected both Friday and Saturday. && .AVIATION... (06Z TAFS) Issued at 1206 AM CDT Mon Jun 3 2024 Main concern is the MCS moving in from the northwest but as expected it is quickly weakening. That said it will still move in and should impact MCB and BTR with mostly light to moderate SHRA but embedded TSRA. These 2 terminals likely will drop into MVFR status mainly from CIGs but if the moderate SHRA or even TSRA moved over VSBYS will take a drop as well. Elsewhere the rest of the terminals likely will not see any impacts until convection tries to refire in the afternoon hours. Only other thing to mention is outside of rain there could be some light fog mainly impacting MCB. /CAB/ && .MARINE... Issued at 254 PM CDT Sun Jun 2 2024 No significant weather concerns are anticipated in the coastal waters through the end of the week. Winds will initially remain out of the south and southeast at around 10 knots through Wednesday and seas will remain in the 1 to 2 feet range. On Thursday, a weak front will slip through the waters, and winds will briefly turn northerly at 10 to 15 knots on Friday. Otherwise, the only concern through the week will be the risk of locally higher winds and waves near any thunderstorms that form this week. It is safe to say that we are moving toward a very typical Summer pattern this week. && .PRELIMINARY POINT TEMPS/POPS... MCB 87 71 89 71 / 50 50 30 10 BTR 88 73 90 74 / 40 30 20 10 ASD 88 74 89 75 / 20 20 30 10 MSY 87 76 88 77 / 30 20 30 10 GPT 86 76 86 77 / 20 20 30 10 PQL 86 74 86 74 / 20 20 30 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...PG LONG TERM....PG AVIATION...CAB MARINE...PG