textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 358 AM CDT Mon Sep 7 2026

- Scattered showers and storms are forecast throughout the forecast period. The overall severe weather threat will be low, but one or two storms could become strong to severe.

- Primary threats with storms will be strong wind gusts, frequent lightning and periods of heavy rain leading to localized flash flooding.

- Above normal temperatures expected most of the 7-Day forecast period. Afternoon heat indices will generally range from 100 to 108 degrees. Heat Advisories have been issued for portions of the region on Labor Day.

SHORT TERM

(Now through Thursday) Issued at 358 AM CDT Mon Sep 7 2026

The main forecast challenges today through midweek will be how much convection develops this afternoon, the associated conditional damaging wind threat, and the transition toward a wetter pattern Tuesday through Thursday. Early this morning, the region remains along the southern and southeastern periphery of a somewhat ragged mid-level ridge centered over the Southern Plains, while troughing over the eastern CONUS continues to push somewhat drier air toward the region from the northeast. A notable moisture gradient will be evident today, with forecast PW values generally around 1.7 to 1.9 inches within the drier portion of the airmass and increasing to around 2.1 to 2.2 inches along and south of the I-10/12 corridors. Convective coverage remains the biggest uncertainty for this Labor Day 2026. Large-scale forcing is weak and CAM guidance remains rather inconsistent, ranging from very little development in some RRFS solutions to considerably more afternoon convection in the HRRR and other CAMs. Given strong daytime heating, abundant low-level moisture, the nearby moisture gradient and weak mesoscale boundaries, scattered afternoon thunderstorms still appear reasonable, with somewhat greater coverage expected across the more deeply moist southern and eastern portions of the CWA. While storm coverage itself is uncertain, any storms that do develop will have the potential to become rather intense. Forecast soundings indicate a pronounced drier layer aloft with DCAPE generally on the order of 800 to 1000 J/kg in portions of the area. Combined with strong instability, this will favor efficient downward momentum transport and evaporative cooling within heavier cores. With weak vertical shear, storms should remain primarily pulse-type and poorly organized, but an isolated damaging downburst will be possible during the mid to late afternoon and early evening. Thus, the severe threat is conditional primarily on whether sufficient convective coverage can develop, with damaging wind the main concern. The same storms will also be capable of heavy rainfall. The highest rainfall efficiency are more likely south of the I-10/12 corridors and the coast where PW values exceed 2 inches. Weak steering flow and interactions between sea breeze/outflow boundaries could allow a few storms to move slowly or repeatedly affect the same locations. However, with no strong or persistent focusing mechanism and uncertainty regarding overall storm coverage, any flooding threat today should remain localized and mainly confined to poor drainage locations or areas receiving repeated heavy downpours. Prior to convection, temperatures should climb into the middle and upper 90s across much of the area. Combined with the humid boundary layer, peak heat index values of 108 to around 112 degrees are expected across much of southeast Louisiana and southern Mississippi. A Heat Advisory remains in effect from 11 AM through 7 PM. The eventual coverage and timing of convection will be important, as earlier development would cut off heating before heat advisory conditions occur. Convection should diminish fairly quickly inland this evening with loss of heating, although some activity may linger near the coast and over the marine waters overnight.

On Tuesday, the center of the upper ridge shifts farther east and southeast toward Arkansas while the eastern side of the ridge temporarily expands eastward as the eastern CONUS trough moves into the western Atlantic. Over the CWA, we sit right on the southern edge of the ridge. Global models suggest a weakness, possibly inverted trough tracking west across the northern Gulf Coast. This feature, combined with ample moisture throughout the column, should allow thunderstorm coverage to begin increasing, especially across southeast Louisiana and the coastal counties where moisture will be deepest. Northern portions of the CWA may be somewhat slower to see the increase depending on moisture depth(could still have PW's around 1.8"). For temps, increasing convection and cloud cover should begin taking the edge off the heat compared with today but still looking at highs in the 90s. Heat indices will still commonly reach or exceed 105 degrees but am less confident that a heat advisory will need to be issued for a second consecutive day.

A more noticeable pattern change starts takes shape Wednesday and Thursday. The ridge becomes increasingly flattened as stronger northern stream troughing progresses eastward across the northern- central US and shortwave energy on its southern flank digs toward the mid Mississippi Valley. By Thursday, this effectively creates a weakness or split within the ridge over or near the region. Deep moisture and loss of subsidence should result in much greater convective coverage. POPs generally increase into the 50 to 80 percent range, with the greatest coverage favored along the coastal areas along/south of I-10. With PW values remaining high and steering flow relatively weak, locally heavy rainfall will become increasingly common Wednesday and Thursday. Repeated convection along lingering outflow boundaries could produce localized flooding, especially in urban and poor drainage locations, although confidence remains low in identifying any particular corridor for excessive totals this far out. Greater cloud cover and earlier convective development should also hold afternoon temperatures closer to seasonal normals, generally around 90 for Wednesday and Thursday.

MEFFER

LONG TERM

(Thursday night through Sunday) Issued at 358 AM CDT Mon Sep 7 2026

Definitely looks like we should see a pattern shift heading into the end of the work week and next weekend. Operational models and associated ensemble means all show our ridge being suppressed prior to Thursday night and then a trough which will be dropping southeast splitting the ridge in two over the Lower MS Valley and southeastern CONUS which continue to allow for what looks like decent coverage of showers and thunderstorms daily. Latest NBM is in agreement and and is generally showing near 60-70% over the southern half of the CWA each day and near 50% across southwestern MS. With what the models are showing see no reason to deviate from that.

As mentioned the ridge will already be suppressed but Thursday night as the first in a series of northern stream s/w works across the central and northern CONUS our ridge will get split over the Lower MS Valley and southeastern CONUS. We will see the center of one ridge well off to the west over extreme western TX, NM, and northwestern Mexico while a large broad ridge will extend across the western Atlantic over the Bahamas and into the southwestern Gulf (Bay of Campeche). This trough axis/weakness will remain over the area Friday through Sunday. That alone would allow for the potential of daily storms however, given that the trough won't work through the area and really be more of a weakness we will not see the moisture get suppressed as PW's will likely remain in the 1.9 to 2.1 range. At the sfc There will be a weak front move east-southeast through the central CONUS and into the Mid MS Valley and then towards the southeastern CONUS but with the bulk of the mid lvl forcing mainly racing east and no real trough digging into the southeastern CONUS there will be very little support with this front and now most if not all of the guidance suggest this front will not make it anywhere close to the region. That could be a positive thing as that front could lead to more problems if it makes it closer to the area. It will not have the support to continue to push south into the Gulf or deeper. If it could that would likely help to clear out some of the moisture but in all honesty it probably would stall over or near the area and that would bring about the concerns for more focused heavy rain. So, with weakening front looking like it will hang up well to our north we will still see things more focused on outflow boundaries and lake/sea breezes and that helps to keep the potential for heavy rain and flashing flooding more isolated and not across a larger area. Luckily the upper level setup doesn't look quite as favorable for very efficient rain until maybe more Sunday but that still doesn't indicate any real strong upper level diffluence or divergence. /CAB/

AVIATION

(06Z TAFS) Issued at 358 AM CDT Mon Sep 7 2026

VFR conditions dominate the forecast through at least mid morning. A CU field should begin developing across the region around 14-16Z with bases likely ~5kft. The most realistic potential aviation impact is afternoon thunderstorms. However, confidence is lower than normal in terms of if convection will actually develop. Greatest chance for any storms is at KNEW, KMSY and KHUM, where deeper moisture will be in place. PROB30 TSRA groups remain appropriate for those terminals generally during the 18-24Z period. Coverage around KBTR, KMCB and KASD looks more isolated and confidence in direct terminal impacts is too low for a PROB30 at this time. Drier air aloft increases the odds of strong downburst winds with stronger cells today. In addition, any storm could produce IFR visibility, lower ceilings and sudden wind shifts at terminals.

MEFFER

MARINE

Issued at 358 AM CDT Mon Sep 7 2026

The pressure gradient will remain weak through the period with generally benign background marine conditions. Winds should mostly remain around 10 knots or less with seas around 1 to 2 feet through the short term. The primary marine concern will continue to be thunderstorms. Deep moisture remaining over the northern Gulf will favor scattered convection over the coastal waters, particularly during the late night and morning hours before the focus shifts inland with the sea breeze during the afternoon. Coverage should remain elevated through Monday as the upper trough approaches and weakens subsidence, despite the backdoor front likely remaining east of the local waters. Daily thunderstorm chances continue through the remainder of the week and may increase somewhat late in the week as the upper ridge weakens and troughing becomes more influential. Outside of convection, conditions should remain well below advisory criteria. The stronger storms will remain capable of locally gusty winds and briefly higher waves.

MEFFER

LIX WATCHES/WARNINGS/ADVISORIES

LA...Heat Advisory from 11 AM this morning to 7 PM CDT this evening for LAZ034>037-039-046>048-056>058-064-071-076>087-089>100.

GM...None. MS...Heat Advisory from 11 AM this morning to 7 PM CDT this evening for MSZ068>071-077-083-086.

GM...None.