textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 630 PM CDT Thu Jun 18 2026

- A Flood Watch is in effect through Friday morning for most of southeast Louisiana as well as all of southwest and coastal Mississippi.

- Dangerous conditions for mariners of small craft and minor coastal flooding on south facing shores west of the Mississippi River will persist through tonight as Post Tropical Cyclone Arthur moves into southwest Louisiana.

- Extreme heat is expected this weekend. Heat advisories will likely be issued for heat index values of around 110 degrees.

SHORT TERM

(Now through Sunday night) Issued at 144 PM CDT Thu Jun 18 2026

Conditions will greatly improve as we move into tonight and rest of the short term period in terms of the heavy rainfall threat. A broad deep layer ridge axis will expand northward across the Gulf South resulting in lower overall rain chances as we move into Friday and Saturday, but the side-effect will be significantly warmer temperatures. Highs will easily climb into the low to mid 90s and very high dewpoints in the upper 70s and lower 80s will produce heat index readings of around 110 degrees Friday through Sunday. A heat advisory has been issued for much of the area for tomorrow and additional heat advisories may be issued for the weekend. Ample instability will accompany these warm temperatures with MLCAPE of 2000 to 2500 J/KG both days. As a result, diurnally induced convection will form each day with the highest probabilities north of I-12 where the influence of the mid to upper level ridge will be lower. Although PWATS will fall to more average levels by Saturday and Sunday, the wet antecedent conditions could lead to isolated flash flooding incidents as rainfall rates still average 1 to 2 inches per hour.

LONG TERM

(Monday through Wednesday night) Issued at 144 PM CDT Thu Jun 18 2026

The influence of the ridge will grow as we move into next week with lower overall rain chances and continued warm temperatures. Highs will easily continue to climb into the low to mid 90s each day and overnight lows will only cool into the upper 70s and lower 80s. Heat index values will continue to rise to between 105 and 110 degrees, so more days of heat advisory conditions can be expected. The growing influence of the ridge will lead to a strong mid-level capping inversion and overall lower rain chances from Sunday through Tuesday with only isolated to widely scattered afternoon showers and storms anticipated. Rain chances will be highest over the northern third of the forecast area where the capping inversion will be slightly weaker.

The ridge will begin to weaken on Wednesday as a shortwave trough axis moves in from the northwest. This will allow for steeper lapse rates in the mid-levels and overall increased rain chances for Wednesday afternoon. This is reflected by increased PoP values fo 30 to 50 percent. Sounding review indicates some potential for an isolated strong to severe thunderstorms, mainly wind, due to some linger mid-level dry air.

AVIATION

(00Z TAFS) Issued at 630 PM CDT Thu Jun 18 2026

Conditions have improved in terms of thunderstorm threat as the remnants of the tropical system continue to move east of the region. Lingering MVFR ceilings will be in place at all of the terminals through tonight and into tomorrow morning. At MCB, a period of low stratus and fog could develop around 10 to 14z in the morning as a weak inversion tries to develop. This could produce a period of IFR conditions at this terminal. VFR conditions should return to the all of the terminals after 15z as drier air begins to feed in.

MARINE

Issued at 144 PM CDT Thu Jun 18 2026

Strong southerly winds of 20 to 25 knots with gusts of 30 knots will remain in place over the coastal waters through this afternoon in the open Gulf waters. Small craft advisories remain in effect due to these conditions. Moving into the weekend and early next week, a broad area of high pressure will build back over the eastern Gulf waters. Persistent onshore winds of 10 to 15 knots and seas of 2 to 4 feet can be expected from Friday through early next week.

LIX WATCHES/WARNINGS/ADVISORIES

LA...Flood Watch through Friday morning for LAZ034>037-039-046>048- 056>058-064-071-076>087-089-090-092-094-096-098>100.

Heat Advisory from 10 AM to 7 PM CDT Friday for LAZ034>037-039- 046>048-056>058-064-070-071-076>087-089>100.

GM...Small Craft Advisory until 6 AM CDT Friday for GMZ529-531>536- 541-543-551-553-554-557-570-572-575-577.

MS...Flood Watch through Friday morning for MSZ068>071-077-083>088.

Heat Advisory from 10 AM to 7 PM CDT Friday for MSZ068>071-077- 083-086.

GM...Small Craft Advisory until 6 AM CDT Friday for GMZ531>536-541- 543-551-553-554-557-570-572-575-577.