textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 115 PM CDT Sat Jun 20 2026

- Scattered storms will remain around the area through the weekend. These storms will be capable of producing isolated areas of severe weather and flooding rainfall.

- Extreme heat is expected for Monday and Tuesday. Heat index values should approach 108 degrees and heat advisories may be necessary.

SHORT TERM

(Now through Tuesday night) Issued at 115 PM CDT Sat Jun 20 2026

This afternoon, an outflow boundary associated with a cold pool that formed from a morning MCS over north Louisiana and central Mississippi is drifting southward across the CWA. The boundary currently extends from near Poplarville westward to Baton Rouge. As the boundary sinks to the south, scattered showers and storms will fire up along and immediately behind the boundary. These showers and storms are expected to remain below severe limits today, but locally higher rainfall rates of 1 to 2 inches per hour on already saturated soils could lead to some localized flash flooding issues in coastal Mississippi. The outflow boundary will eventually stall in the general vicinity of the River Parishes and metro New Orleans tonight, and periods of scattered showers and storms will redevelop along the boundary. This redevelopment will be driven by the passage of a weak upper level vorticity max on the northern periphery of a strong mid to upper level high dominating the Gulf. Weak forcing associated with the vorticity max will combine with the continued moist and unstable airmass to produce periods of additional scattered shower and thunderstorm activity near the boundary through the night. This convection should remain on the weaker side, but quick downpours on already saturated ground will quickly run off. Some minor street flooding issues will be possible.

Tomorrow will be a day of transition as the boundary begins to lift back to the north in response to increased southerly flow associated with a strengthenin surface high over the eastern Gulf. Additional scattered shower and thunderstorm activity will continue to develop along the boundary in the morning and afternoon hours for areas north of the I-10/12 corridor. Given the antecedent conditions, even with lower rainfall rates of around 1 inch per hour, some localized flooding issues could occur, especially on the Northshore and in coastal Mississippi. Fortunately, this will be the last dose of rain for the rest of the short term period as the strong deep layer ridging over the Gulf expands northward across the area.

Monday and Tuesday will be warm and dry with lower than average PWATS and a strong mid-level capping inversion reducing convective potential to nearly zero. At most, a scattered fair weather cumulus field will develop each day beneath the strong mid-level capping inversion. Temperatures will also warm significantly, rising from the upper and lower 90s today and tomorrow into the low to mid 90s for the start of the workweek. Dewpoints will continue run in the upper 70s and heat index values will climb back above 105 degrees each day. Some mixing of drier air aloft down to the surface could keep values just below heat advisory levels, but conditions will be very hot in general with moderate to major HeatRisk indicated. This means that everyone should take the proper heat precautions when working outdoors early next week.

LONG TERM

(Wednesday through Friday night) Issued at 115 PM CDT Sat Jun 20 2026

A northern stream trough will begin to deepen over the eastern half of CONUS on Wednesday. As this troughing develops, the flow aloft will turn more northwesterly. There are indications that a large MCS could form over the southern Plains Tuesday night into Wednesday morning and then sweep southeastward, following the theta-e moisture axis, into the forecast area by the afternoon hours. The system will be weakening as it moves into the area, but gusty winds and some locally heavy downpours will be possible across the northern half of the CWA during this time period. The increase in cloud cover and rain chances will also help to temper the extreme heat with highs falling closer to average in the upper 80s and lower 90s and heat index readings dropping back to between 100 and 105 degrees.

Thursday will see the upper level trough begin to pull to the east and the influence of the upper level ridging begin to increase. Overall, the day should be a fairly typical Summer day with highs climbing into the low 90s and scattered diurnally induced convection firing up in the late morning and afternoon hours. Rain chances will be highest north of I-10 where the influence of the ridge will be lowest and near average PoP for late June of 30 to 50 percent is forecast. South of I-10, only isolated activity is expected due to the slightly stronger capping inversion aloft.

Friday will continue to see the influence of the ridge grow as the trough pulls out of the area. A return to a warmer and drier pattern is expected as temperatures climb back into the low to mid 90s and rain chances fall to around 20 percent for the afternoon hours. These lower rain chances are direct result of the drier air dropping PWATS below average or around 1.5 inches and the increasing mid-level capping inversion that reduces mid-level lapse rates to below 6.0 C/km and drops MLCAPE to around 500 J/KG. The one thing to keep an eye on is the threat of strong wind gusts from any storms that do form as dry air entrainment into the updraft could occur.

AVIATION

(18Z TAFS) Issued at 115 PM CDT Sat Jun 20 2026

The primary concern will scattered shower and thunderstorm activity forming along an outflow boundary sinking southward this afternoon. TEMPO and PROB30 wording is in place with a mix IFR and MVFR visibility impacts as these storms move through from now through around 02z. A brief break in activity is expected after 02z, but additional activity is projected to form after 06z and last into the morning hours. PROB30 wording is in place at most of the terminals with MVFR impacts. At MCB, some IFR ceilings are also expected to develop around 12z beneath an elevated temperature inversion. The thunderstorm threat will begin to improve at nearly all of the terminals after 18z as the boundary lifts north out of the area.

MARINE

Issued at 115 PM CDT Sat Jun 20 2026

A broad area of high pressure will build back over the eastern Gulf waters as we move into the new week. Persistent onshore winds of 10 to 15 knots and seas of 2 to 4 feet can be expected through much of next week. A brief window of stronger winds up around 15 to 20 knots tonight over the waters west of the Mississippi River has prompted the issuance of exercise caution headlines. These winds will quickly relax tomorrow as the high builds in.

LIX WATCHES/WARNINGS/ADVISORIES

LA...None. GM...None. MS...None. GM...None.