textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 718 PM CDT Sun May 3 2026

- Next potential for strong to severe storms and heavy rainfall will be with a frontal passage Wednesday night.

- Additional rounds of rain, occasionally heavy, are expected Thursday through Saturday.

SHORT TERM

(Now through Tuesday night) Issued at 1239 PM CDT Sun May 3 2026

A very dry and stable airmass will remain over the area through Tuesday as a broad ridge of high pressure extends across the Southeastern CONUS. This dry low to mid-level air will effectively inhibit most cloud development each day. At most, there could be some scattered fair weather cumulus that forms beneath a strong mid- level capping inversion. Temperatures will continue to gradually modify with highs warming from the mid 70s this afternoon into the low to mid 80s by Tuesday afternoon. Given the dry airmass in place, a large diurnal range is expected. The NBM has shown a high bias with overnight lows, so the NBM 10th percentile was used for low temperatures tonight and tomorrow night. This results in lows falling back into the upper 40s and lower 50s over inland areas and the mid 50s south of Lake Pontchartrain for tonight. Tomorrow night will be slightly warmer with lows in the low to mid 50s inland the low 60s south of the tidal lakes. Persistent onshore flow on Tuesday will push higher dewpoints into the region, and this will keep overnight lows elevated in the 60s and lower 70s for Tuesday night. A broken layer of stratus may form around daybreak due to the increasing low level moisture into the region.

LONG TERM

(Wednesday through Saturday night) Issued at 1239 PM CDT Sun May 3 2026

A significant shift in the models this morning with both the ECMWF and GFS solutions showing a frontal boundary stalling over the region on Thursday and lingering through Saturday. The reason for the front stalling is that the parent trough and strongest dynamic forcing will quickly shift to the east on Thursday and a more zonal flow regime will develop over the area in the mid and upper levels. The end result of this change is that a series of fast moving southern stream vorticity maxima and their associated weak surface reflections could produce multiple rounds of thunderstorms and heavy rainfall over the area to end the week.

Before the front moves into the area on Wednesday, very warm temperatures in the mid to upper 80s are expected. A review of model soundings indicates that ample instability will be in place by the afternoon with MLCAPE peaking around 1500 to 2000 J/KG and mid-level lapse rates approaching 7.0 C/km. These values will persist into the evening hours as the right entrance region of a 140 knot 300mb jet streak moves through the Lower Mississippi Valley. This will result in a very strong deep-layer forcing across the ArkLaMiss region including the northern half of the forecast area. In the low levels, a potent 50 knot low level jet form at 850mb over southern Mississippi. As this occurs, 0-6km speed shear will rise to around 60 knots over the northern third of the forecast area. Further to the south, speed shear of 40 to 50 knots will be in place. Additionally, the wind field will exhibit sufficient turning with height as noted by 0-3km SRH values of 200 to 250 m2/s2 over the northern third of the CWA. The combination of all of these factors support the development of severe thunderstorms over the northern third of the CWA including in southwest Mississippi and the Florida Parishes Wednesday evening. Given the strong shear and ample instability, all convective modes are possible Wednesday night including a risk of supercell thunderstorms with tornadoes, hail, and damaging wind gusts over the northern third of the CWA.

As we move into Thursday, Friday, and Saturday, the stationary front over the region will serve as the main focusing mechanism for multiple rounds of heavy rainfall. The severe potential will be diminished due to a lack of shear, but high PWATS of 1.5 to 1.8 inches will be place through the period. Both the GFS and ECMWF indicate that fast moving and weak upper level impulses embedded within the zonal flow regime aloft will pass through the region. In the low levels, weak surface low pressure systems will form along the boundary in a region of enhanced baroclinicity. The low pressure systems will help drive the development of a series of mesoscale convective systems that will move across the Gulf South from east Texas into the Florida Panhandle each day. Given the higher PWATS and more saturated soils in place, flooding will become a more significant concern as we move into Friday and Saturday. Temperatures will be near average to end the week due to the largely zonal flow regime in place.

AVIATION

(00Z TAFS) Issued at 718 PM CDT Sun May 3 2026

No concerns over the next 24 to 48 hours as VFR conditions will continue with light winds. /CAB/

MARINE

Issued at 1239 PM CDT Sun May 3 2026

High pressure will continue to settle over the waters tonight into tomorrow resulting in light winds and calm seas. As the high pulls to the east on Tuesday, winds will turn 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.