Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
182 FXUS64 KLIX 041714 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1214 PM CDT Mon May 4 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .KEY MESSAGES... Updated at 1206 PM CDT Mon May 4 2026 - Next potential for strong to severe storms and heavy rainfall will be with a slow moving frontal boundary Wednesday night or Thursday. - Additional rounds of rain, occasionally heavy, are possible Thursday through Saturday. && .SHORT TERM... (Now through Wednesday) Issued at 1206 PM CDT Mon May 4 2026 Upper lows were noted over Western Ontario and near San Francisco this morning. Upper ridging was over Mexico into the southern Rockies, and off the British Columbia coast. This was producing almost zonal flow across the local area, although there was a weak shortwave over Arkansas. At the surface, high pressure was centered over Chandeleur Sound this morning. This was the western end of a Bermuda High surface pattern. Mostly clear skies across the area this morning with a dry airmass. Precipitable water values on the 12z sounding were around 0.5 inch, which is below the 10th percentile. Dew points were in the mid and upper 40s and temperatures have climbed quickly into the mid 70s. The upper low near San Francisco this morning will drop southeast into Arizona by tomorrow evening, then begin shearing out, as a northern stream shortwave drops southeastward through the Rockies on Wednesday. This will gradually induce a southwesterly mid level flow across the local area. By the time we get to Wednesday afternoon, the upper flow will become nearly parallel to the surface frontal boundary. As the surface high continues to slide eastward today, surface winds will become southerly, with moisture levels beginning to increase. By Tuesday afternoon, precipitable water values will be near 1.4 inches (75th percentile), and 1.7 inches Wednesday afternoon (90th percentile). A weak impulse moving through Arkansas in the southwesterly flow will likely be close enough to aid the development of isolated to scattered showers and thunderstorms across about the northern third of the area by Wednesday afternoon. Forecast soundings indicate sufficient instability and shear for strong to severe storms with the main question whether the local area is capped. It is entirely possible that the local area remains dry through Wednesday afternoon, but not planning on radical changes to Wednesday PoPs with this package. Temperatures tonight won`t be quite as cool as this morning, but still a touch below normal. Highs tomorrow and Wednesday will be in the low to mid 80s, with lows Wednesday morning mid 60s to lower 70s. && .LONG TERM... (Wednesday night through Sunday night) Issued at 1206 PM CDT Mon May 4 2026 With the orientation of the surface front nearly parallel to the mid level flow, any frontal passage is going to be slow to occur. It may be as late as midday Friday before the front clears lower Plaquemines Parish. Not much consensus between ECMWF and GFS solutions on timing of showers and thunderstorms beyond Wednesday night/Thursday. The ECM and its ensemble are considerably drier, especially from daytime Friday through Saturday night. Expect there will be multiple rounds of convection beyond Thursday, but until there`s some agreement between model solutions, NBM PoPs will have to suffice, with potential for changes pretty high. As long as the frontal boundary remains in the area, showers and thunderstorms will be possible. Obviously, if this pattern continues for several days, it`ll have a cumulative effect on flooding potential. The heaviest totals right now look to be north of our area, but a widespread 1 to 2 inches of rain through the weekend certainly looks to be attainable, and very possibly quite a bit more if the GFS is on the right track. Temperatures will be near to above normal for the period, with the potential for cloud cover/precipitation the main concern for high temperatures. && .AVIATION... (18Z TAFS) Issued at 1206 PM CDT Mon May 4 2026 VFR conditions in place and expected to continue for most or all of the forecast period. Could see some SCT to BKN cumulus by late morning tomorrow, but any ceilings below FL030 should be relatively brief. && .MARINE... Issued at 1206 PM CDT Mon May 4 2026 High pressure will pull to the east on Tuesday, causing winds to become southerly and increase to 10 to 15 knots. Further increases to 15 to 20 knots or exercise caution conditions will occur on Wednesday as a low pressure system passes to the north of the area. A weak front will slip into the waters and stall over the region on Thursday leading to more variable winds of 10 to 15 knots. By Friday, the weak front will dissipate and southeast winds of 10 to 15 knots will return. && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RW LONG TERM....RW AVIATION...RW MARINE...RW