Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
938 FXUS64 KLIX 301950 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 250 PM CDT Mon Jun 30 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .SHORT TERM... (This evening through Wednesday night) Issued at 213 PM CDT Mon Jun 30 2025 A dirty upper level ridge will remain parked over Texas and western Louisiana through Wednesday, and this will keep a prevailing northwesterly flow regime in place across the forecast area. This dirty ridge will have ample moisture associated with it as noted by PWATS averaging around 2 inches through Wednesday afternoon. A series of weak upper level impulses will slide down from the northwest over this period, and these weak regions of increased upper level forcing will support continued higher than average convective coverage each day as the lift taps into a warm and moist airmass. This convection will generally peak over marine zones and the immediate coastal land zones in the late overnight and morning hours. The most likely region of development will be along a weak land breeze that stalls just offshore each night. During the day, that land breeze will shift back to a sea breeze, and additional convective activity will form as this sea breeze moves inland and interacts with an increasingly unstable airmass as temperatures climb into the upper 80s and lower 90s. The thunderstorm activity will be most pronounced along and south of the I-10/12 corridor where seabreeze interactions will be strongest. Further inland, toward Southwest Mississippi, the shower and thunderstorm will be more isolated to widely scattered and will tend to develop along any pre-existing remnant outflow boundaries in place. A weak frontal boundary is then expected to push through the area Wednesday afternoon into Wednesday night. Additional convective development will occur along the front, but a surge of much drier and more stable will begin to advect into the region behind the front. PWATS will fall a good three quarters of an inch by Wednesday night with values of 1.25 to 1.50 inches expected. The end result will be a much drier forecast for Wednesday night as the front stalls over the coastal waters with any shower and thunderstorm activity confined to locations south of I-10. && .LONG TERM... (Thursday through Sunday night) Issued at 213 PM CDT Mon Jun 30 2025 Drier and more stable conditions will persist over the forecast area through Saturday as increasing upper level subsidence from the ridge results in lower PWATS of 1.25 to 1.5 inches persisting. The drier air aloft will also support a fairly robust mid-level capping inversion, and this will help to limit convective potential and overall convective coverage each day. Conditions will not be completely dry, but any storms that form will be more isolated and will tend to form later in the day as temperatures climb high enough to overcome the capping inversion aloft. Any storms that develop will also form along the weak seabreeze or a weak outflow boundary from previous storms. PoP values reflect the lower overall threat with the forecast calling for 20 to 40 percent rain chances from Thursday through Friday across the area. The highest rain chances will be along and south of I-10 where the seabreeze boundary will be strongest. Temperatures will also respond to the drier air and lower cloud development with readings easily rising into the mid 90s on Friday and Saturday. Heat index readings will range from 105 to 108, or very near advisory criteria on these days. By Sunday, the ridge is expected to weaken and shift to the west as an inverted trough axis embedded within the easterly regime aloft moves toward the central Gulf coast. This inverted trough will provide not only increased forcing aloft, but will also advect in a much more tropical airmass. PWATS will once again push up to between 2 and 2.25 inches, and this will support increased convective activity during the peak heating hours Sunday afternoon. PoP values are forecast to rise to between 40 and 60 percent and rainfall rates will also increase as temperatures warm aloft and more efficient rainfall processes are supported. The increased shower and thunderstorm activity will also allow for slightly cooler temperatures in the lower 90s. However, heat index values will still be high at around 105 degrees. && .AVIATION... (18Z TAFS) Issued at 213 PM CDT Mon Jun 30 2025 Scattered thunderstorm activity will once again be the primary concern at the terminals this afternoon as a highly unstable airmass combines with a broad area of low pressure over the region to produce these thunderstorms. The threat is reflected at all of the terminals by PROB30 wording with TSRA and MVFR ceiling and visibility impacts mentioned generally between 18z and 00z. Winds may be gusty and erratic and up to 30 mph with these storms as well. After 00z, the thunderstorm threat will diminish with the loss of daytime heating, and prevailing VFR conditions will take hold at all of the terminals. However, at MCB, a period of light fog and MVFR visibilities has a moderate probability of development between 10z and 13z, and this is reflected by a TEMPO group over this time period. Additional PROB30 groups are included at GPT, ASD, NEW, and MSY for tomorrow as more convection is expected to fire up in the morning hours. PG && .MARINE... Issued at 213 PM CDT Mon Jun 30 2025 A fairly typical Summer pattern will be in place over the coastal waters through the weekend. This means the seabreeze cycle will dominate with light winds and relatively calm seas. However, scattered thunderstorms could produce locally higher winds and seas at times. A weak front will then move into the waters Wednesday night and stall. This front will keep a risk of thunderstorms and locally higher winds and waves in place through the end of the week. Otherwise, winds will remain very light and variable in the vicinity of the front. No significant impacts to mariners other than thunderstorm activity is expected. && .PRELIMINARY POINT TEMPS/POPS... MCB 73 92 72 92 / 30 60 30 40 BTR 75 92 75 92 / 20 50 20 50 ASD 75 91 75 92 / 40 60 40 50 MSY 77 91 78 91 / 30 60 40 60 GPT 76 88 76 90 / 50 70 50 40 PQL 73 88 74 90 / 60 70 50 40 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...PG LONG TERM....PG AVIATION...PG MARINE...PG