textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 631 PM CDT Tue Jun 16 2026

- Potential for Life Threatening Flash Flooding

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

- Continuing to monitor Potential Tropical Cyclone over deep south Texas as it moves northeast toward the northwest Gulf Coast on Wednesday. There is a high chance (70%) of development. Marine and heavy rain will be the primary impacts.

- River flooding potential exists as well with forecast areal rainfall amounts of 5 to 10 inches with isolated amounts much higher.

SHORT TERM

(Now through Friday night) Issued at 1259 PM CDT Tue Jun 16 2026

A broad mid/upper level trough still encompasses most of the country, with only the southwestern and West Coast states not under this trough. The N/S axis is roughly from the Great Lakes to Dauphin Island. A stalled frontal boundary remains draped across the region today and will continue to serve as the primary focus for showers and thunderstorms. A very moist tropical airmass remains in place, with observed and forecast PW values around 2.2-2.4". This moisture, combined with a deep warm cloud layer, will support very efficient rainfall production in any convection.

Radar shows a wide swath of showers and thunderstorms tracking west to east across south Louisiana and MIssissippi. Instability has increased, moreso where cloud convection is less robust, with SBCAPE near 1500 to 2000 J/kg and little to no inhibition. While both low and mid-level lapse rates remain weak, overall storm organization should be limited, the environment will support locally heavy rainfall rates for the most part.

The main hazard through this afternoon and evening will be localized flash flooding. Multiple locations across the CWA have already seen upwards of 5-8" rain, resulting in flash flooding. So while storms may move individually, repeated development along the same corridor could lead to quick rainfall totals of 2 to 4 inches, with isolated quite a bit higher where training occurs. Urban and poor drainage areas will be most vulnerable.

A secondary concern will be a low-end tornado threat. Low cloud bases, sufficient low-level shear (30kts), SRH 200-300 SRH, and boundary interactions could support a brief tornado or two, especially with any stronger surface-based storm that can interact with the stalled front or outflow boundaries. A few circulations have already been observed earlier this morning. This threat should remain localized and conditional, but bears watching given the observed low-level shear and boundary-rich environment.

Convection should gradually decrease in coverage later this evening with loss of heating, but showers and a few thunderstorms may persist near the boundary. Any lingering storms will remain capable of brief heavy rainfall. The tornado threat should diminish after sunset as instability weakens, though a brief spin-up cannot be completely ruled out near any persistent boundary.

Wednesday is a bit more interesting. The low that prompted PTC advisories for areas west of the CWA is forecast to track northeast along the Texas coast. CAMs have begun to show quite a bit less convection locally as that system approaches the northern Gulf Coast. That's likely as a result of subsidence on the periphery what NHC forecasts will be a tropical storm. However, the atmosphere aloft will still be quite saturated. What you end up with is less convection, so more sunshine which allows for more warming and more instability. Weak low level wind field will be the biggest limit to TOR potential, but still think there's a low-end conditional threat. That threat

Thursday carries a mix of threats similar to both today and Wednesday, but in different ways. Remnant tropical low should be north to northeast of the CWA by this point in the forecast period. That position in relation the the local forecast area is definitely conducive for rain band training. This is something we've seen in the area time and time again. The result of this setup is widespread light/moderate rainfall totals with streaks of very high rainfall amounts. CAMs suggest 10-20" isolated totals certainly within the range of possibilities. But like all events, if that's over Lake Pontchartrain, no one but the fish are impacted. The other side of this setup potential is weak TORs embedded within any stronger rain bands, especially where differential heating enhances near-surface instability along boundary/outflow interactions within an already moist, low-LCL, and modestly sheared environment.

LONG TERM

(Friday night through Monday) Issued at 153 AM CDT Tue Jun 16 2026

By Friday evening, the tropical system should be east of the local area, although it appears a weakness in the mid level flow will remain along the northern Gulf coast until about Sunday before shortwave ridging builds back into the area.

Precipitable water values will remain above 2 inches until the daytime hours Saturday, but won't get significantly below two inches until Sunday evening. We should see a gradual lowering of convective coverage Saturday and Sunday, with only isolated afternoon storms remaining by Monday afternoon. There may remain at least a low end threat of excessive rainfall over the weekend, but it shouldn't be a complete washout on Father's Day.

Highs likely to get in the upper 80s Friday, and a couple degrees warmer each day Saturday and Sunday, with most of the area in the

AVIATION

(00Z TAFS) Issued at 631 PM CDT Tue Jun 16 2026

Forecast terminals VFR at forecast issuance time, with the exception of KMCB, where IFR ceilings are in place. Through 06z, TSRA expected to remain south of all terminals with the possible exception of KHUM. An area of drying is moving toward the area, cutting off the majority of showers and storms that have been producing heavy rainfall all day. Do eventually expect a builddown of ceilings toward sunrise to MVFR at most terminals, and IFR at KMCB. For most of the day Wednesday, expect to experience MVFR ceilings with scattered to numerous SHRA/TSRA.

MARINE

Issued at 1259 PM CDT Tue Jun 16 2026

Surface pressure pattern is now dominated by a broad ridge centered in the western Atlantic that extends across the entire Gulf. Flow around this feature supports southerly winds generally around 10 to 15 knots through Tuesday night. These conditions will keep seas near 2 to 4 feet across the open Gulf waters, while the sounds and tidal lakes remain closer to 1 to 2 feet.

By early Wednesday, the tropical disturbance currently located over south Texas is forecast to track northeastward along the Texas coast before moving into western and central Louisiana Wednesday night. The interaction between this feature and the strong high to the east will cause winds over local marine waters to increase via tightening pressure gradient. Forecast boundary layer winds well into the mid 20 knot range should be a good proctor for observed winds over the coastal waters. Thus, have issued a Small Craft Advisory during this mid/late week timeframe. Guidance suggests winds won't appreciably relax until this weekend.

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.

Coastal Flood Advisory from 6 AM Wednesday to midnight CDT Wednesday night for LAZ091-093-095-097.

GM...Small Craft Advisory from midnight tonight to 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.

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