textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 640 PM CDT Tue Jun 23 2026

- A Heat Advisory is in effect for areas around Lake Pontchartrain/Maurepas again today for forecast heat index values in the upper 100's - take precautions if you plan to be outdoors for extended periods today!

- Monitoring possible complex of strong/isolated severe storms late Wednesday afternoon/evening approaching from the northwest, with greater focus/confidence for areas east of I-55, including coastal Mississippi and adjacent marine waters. Stay updated!

SHORT TERM

(Now through Friday night) Issued at 1217 PM CDT Tue Jun 23 2026

Starting off with early this afternoon, bouncing off of the morning update, what is left of the anvil canopy continues to spread southeast along progressive NW flow aloft. This continues to dissipate, and have noticed via GOES-16 Ch2 trends that we're still heating up plenty enough for low-level Cu development. Kept the same general edits to today in place from the morning update, including bumping down highs a few degrees, which in turn lowered forecast max heat indicies. Again, not planning on touching the Heat Advisory as we could distinctly still see a few isolated/pockets of 108 and want to emphasize the risk to sensitive groups - caution is advised if you plan on being outdoors for extended periods today.

Otherwise, westerly mean 0-1km flow per HRRR guidance in conjunction of the development of a lake/seabreeze boundary will skew the circulation east, causing some good confluence for eastern/southern parts of the lake. Kept the same uptick of 15% PoPs mainly for the river parishes including metro NOLA. No major impacts anticipated, just something to monitor.

Going beyond into tonight, glancing at verification shows we were actually a bit too cool with lows, noticing a record warm low set at KBTR of 80, a good 5-ish degrees warmer than forecast. Hedged the right direction by implementing the NBM 75th percentile, but could still be too cool in spots. Seems like we've hit the time of the year when we loose the cooldown efficiency overnight, with it still rather warm/muggy through the night providing little relief.

Wednesday, we start with a brief synoptic overview highlighting a 594dm ridge anchored over west Texas/northern MX. With the northern Gulf coast on the NE and E periphery of the ridge with NW flow aloft AND, the proximity of a stationary front/boundary - this spells 1 thing: MCS. Recent HRRR and REFS overview from the 12Z suite shows an ongoing MCS/complex over OK later this evening/tonight, in conjunction with a H5 mid-level impulse/PVA providing dynamic support. Eventual cold pooling will aid to support downstream movement into MS beyond midnight into early Wednesday. While the focused axis/main threat with this initial complex likely to our north, what needs to be watched is 1) the size/magnitude of the attendant cold pool, if larger, could drive the complex axis more from SW to SSW impacting SE MS and SW AL, ultimately impacting coastal MS later in the day. This will need to be watched, as this complex could contain strong wind gusts (mainly sub-severe but could have severe segments, especially over marine areas).

Beyond that going into late-week, the upstream flow north of the ridge straightens out/becomes quasi-zonal and we lose the NW flow aloft, meaning we'll start to warm up and dry out (with the exception of isolated showers or storms collocated with the lake/seabreeze each afternoon). However, temperatures will remain hot continuing into late week. KLG

LONG TERM

(Saturday through Monday night) Issued at 1217 PM CDT Tue Jun 23 2026

Continuing on from the Short-Term, the focus becomes the heat as we really start to climb with highs, providing heat indicies at or surpassing Heat Advisory criteria this weekend. This is supported by the likely development of a deep ridge across the MS river valley region. 594dm H5 ridging will push highs higher into the mid 90's, surging heat indicies into the 108-112 range, so heads up for outdoor activities this weekend, even into early parts of next week while remaining mainly dry. KLG

AVIATION

(00Z TAFS) Issued at 640 PM CDT Tue Jun 23 2026

The primary concern through the morning hours will be the potential for another weak inversion and a low stratus deck to form at a few of the terminals between 10z and 14z. MCB, BTR, HDC, and ASD could see a period of 500 to 800 feet ceilings develop during this time period resulting in some IFR restrictions. After 18z, some PROB30 wording is also included as some storms could fire up in the afternoon hours around GPT, ASD, and MCB. These storms will be associated with a passing MCS and could produce some MVFR visibilities and gusty winds over 30 knots.

MARINE

Issued at 1217 PM CDT Tue Jun 23 2026

Surface high pressure over the eastern Gulf will continue to promote weak, mainly westerly flow today through around Thursday. Otherwise, a series of possible thunderstorm complexes might surge southeast along a stationary front from mainly Mississippi and Louisiana later in the day on Wednesday, delivering the risk for >34kt winds and waterspouts towards the evening/overnight hours. Greatest confidence for the Mississippi Sound. Winds become more onshore/out of the south later this week into the weekend. Conditions dry out more later in the week with ongoing weak winds/waves/seas.

LIX WATCHES/WARNINGS/ADVISORIES

LA...Heat Advisory until 8 PM CDT this evening for LAZ058-064-076>078- 080-082-084-087-098-099.

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