textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 546 AM CDT Fri Oct 2 2026

- Widespread rain and embedded thunderstorms will affect the area Today through Sunday. Rainfall totals of 4 to 6 inches with locally higher amounts and some localized flooding issues are expected, mainly along and south of I-10. Residents should continue to monitor the forecast for updates regarding this threat.

- Larger than normal tide ranges and onshore flow will produce minor coastal flooding on southeast facing shore lines during the high tide cycle the next several nights.

SHORT TERM

(Now through Monday) Issued at 1223 AM CDT Fri Oct 2 2026

The combination of deep tropical moisture, as noted by PWATS near the daily max, a slow moving surface front, and an approaching jet streak will all support categorical PoP of 80 to 100 percent starting today and peaking on Saturday and Sunday. The surge of deep tropical moisture will come from both the Pacific in the form of the remains of Hurricane Polo and from a plume of Gulf moisture feeding in from the southern Gulf. PWATS will rise to between 2.3 and 2.5 inches starting today and persisting through Sunday. The surge of moisture from the Gulf will be aided by the development of a broad baroclinic low pressure system over the western Gulf that will keep a persistent deep layer southeast flow regime in place through the weekend. The peak timing for heavier rainfall to occur will be Saturday and Sunday when the right entrance region of a jet streak associated with the passage of weak upper level trough axis slides into the Lower Mississippi Valley. Increased forcing aloft will work in tandem with low level convergence and forcing along a slow moving surface front that is associated with the approaching trough axis. Enhanced moisture pooling along the front will support the development of more persistent bands of heavier rainfall along and just to the south of the front from Saturday afternoon through Sunday afternoon leading to rainfall totals of 4 to 6 inches for areas along and south of I-10 including coastal Louisiana and Mississippi. Localized amounts could approach 8 inches over the two days. Rainfall rates are not expected to overly excessive as deep and sustained convection is not supported, but several hours of 1 inch per hour rainfall rates will lead to localized flooding issues over time as the ground becomes saturated. For areas north of the front, rainfall totals will be significantly lower in the 1 to 3 inch range over the weekend with most of the rainfall remaining stratiform in nature due to a lack of instability. Temperatures will be near average today, but will fall below average into the low to mid 80s on Saturday and Sunday due to the extensive cloud cover and rainfall expected. A persistent southeast flow of 10 to 15 mph, aided by the developing low in the western Gulf, will allow for continued minor coastal flooding concerns during high tide periods on south and east facing shores through Sunday.

Monday will be a day of transition for the region as the slow moving cold front pushes offshore and the parent upper level trough axis pulls well to the east. A more zonal flow pattern will emerge and the region will still be beneath the right entrance region of a jet streak. Drier air in the mid-levels will begin to advect into the region, and a moisture gradient will emerge with near average PWATS over the northern third of the CWA and above normal values from I-10 southward. Temperatures will remain cool in the low 80s as cold air advection on the back of an increasing northeast wind takes hold, and this will limit instability greatly. Upper level lift from the jet streak and some very weak isentropic forcing over the surface based cold pool will support continued mostly cloudy skies and scattered to numerous shower development for areas south of I-10 on Monday. Further inland, only isolated to widely scattered showers are expected, mainly in the morning, before the drier air fully moves in. Cloud cover will also begin to break up in the afternoon with partly cloudy skies expected by late afternoon.

LONG TERM

(Monday night through Thursday) Issued at 1223 AM CDT Fri Oct 2 2026

Upper ridging will be over the Rockies Monday evening, with shortwaves off the Atlantic Coast and moving through the central Plains States. Ridging will remain over the Rockies for much of next week, with troughing becoming established from west Tennessee to east Texas on Thursday. The frontal boundary that will bring rain to the area this weekend will be over the Gulf by Monday night and not expected to return inland. High pressure centered over Michigan Monday night will move off the Atlantic Coast at midweek. Northeasterly flow early in the week will gradually become easterly, but no real indications that surface flow will become onshore to any great extent.

This pattern looks like it should keep most significant rainfall (> 0.5 inch) offshore for the midweek period, or at best, over the lower portions of the Louisiana coastal parishes. We'll still have precipitable water values exceeding the 90th percentile climatologically Monday night for much of the area (>1.9 inches) and approaching the daily max across the southeast half. Drier air does start working into northern portions of the area Tuesday morning, but it may take until midday Wednesday to get most of the area close to the 50th percentile. Low level moisture (near and below 850 mb) looks to remain pretty high through Thursday. Certainly there is disagreement between the 01/12z operational runs of the GFS and ECMWF on sky cover, with the GFS the more pessimistic on cloud cover for Tuesday through Thursday. Rain chances should gradually lower from the 40-60 percent range on Tuesday to around 20 percent by Thursday, with areas north of the Interstate 10/12 corridors likely remaining dry Wednesday and Thursday.

Will let the NBM temperature forecast ride for now, which has most high temperatures in the lower to middle 80s, but would note that if the more pessimistic GFS (cloudy) trends verify, high temperatures could struggle to get past 80 degrees in some areas Wednesday. The current numbers appear to favor the ECMWF solutions somewhat better.

AVIATION

(12Z TAFS) Issued at 546 AM CDT Fri Oct 2 2026

Aperiod of more widespread shower and thunderstorm activity is expected to impact the coastal terminals of HUM, MSY, NEW, ASD, and GPT between 15z and 00z today. These terminals have prevailing light to moderate rainfall with visibilities of 3 to 5 miles in place over this period, and PROB30 wording for scattered storms that could produce gusty winds, lightning, and IFR visibilities for brief periods of time. Further inland, the rain threat will be lower at HDC, MCB, and BTR with prevailing VFR conditions in place through the entire forecast period. However, PROB30 wording is in place through the afternoon hours to reflect the risk of some passing showers and storms at times that could produce gusty winds, lightning, and MVFR visibilities of 3 to 5 miles. Toward the end of the period after 08z, stratus build down will occur leading to all of the terminals experiencing a mix of MVFR and IFR ceilings impacts. MCB will be most impacted with ceilings falling to around 500 feet. Ceilings should remain between 800 and 1500 feet at the remaining terminals.

MARINE

Issued at 1223 AM CDT Fri Oct 2 2026

A tightening pressure gradient over the coastal waters that will form in response to a developing low pressure system in the western Gulf. This will allow southeast winds to remain elevated near 15 knots with higher gusts through Saturday. Very choppy seas of 4 to 6 feet will accompany these winds in the open Gulf waters. The lakes and sounds will see slightly lower winds closer to 10 knots and choppy conditions through Saturday. Winds will briefly relax to 10 knots or less on Sunday as a front stalls along the coast. This front is expected to then slowly push through the waters on Monday and Tuesday. Winds will turn northeasterly behind the front and increase back to 15 to 20 knots as cooler and drier air advects over the warm waters. Another low will form along the front by Wednesday, and this should increase winds in small craft advisory range of 20 to 25 knots. Seas will also increase to 5 to 7 feet by Wednesday leading to rough conditions. Thunderstorms will also be around today through Monday, but the only main concerns will be from lightning and heavy rainfall reducing visibilities.

LIX WATCHES/WARNINGS/ADVISORIES

LA...Coastal Flood Advisory until 9 AM CDT this morning for LAZ070- 076-078-091-093-095-097.

GM...None. MS...Coastal Flood Advisory until 9 AM CDT this morning for MSZ086>088.

GM...None.