textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 115 PM CDT Fri Jul 17 2026

- A drier pattern is expected into next week. The primary concern will be increasing heat. Heat indices will approach advisory criteria today but should surpass criteria for at least some areas Saturday into next week.

SHORT TERM

(Now through Monday night) Issued at 115 PM CDT Fri Jul 17 2026

Strong subsidence from upper level ridging remains the primary driver of the forecast this afternoon. Regional radar remains essentially quiet across southeast Louisiana and southern Mississippi. A 1022 mb surface high centered just southeast of the Mississippi River mouth is producing light west to northwest flow across the area, while the more active convection associated with a TUTT remains confined to the eastern Gulf and Florida. The 12Z KLIX sounding depicts a potentially unstable but strongly suppressed environment. Precipitable water decent at 1.63 inches but still, a deep dry mid layer combined with subsidence, and absence of a meaningful initiating boundary should prevent any convection today. Will therefore maintain effectively dry conditions today, with less than a 10 percent rain chance throughout the CWA. Highs in the next few hours should reach the middle 90s across most of the CWA with a few upper 90s.

A trough emerging from Canada will cross the Great Lakes Saturday and move into the Northeast Sunday, gradually eroding the eastern edge of the broad CONUS ridge. At the same time, the TUTT low over Florida and the eastern Gulf will remain close enough to modestly weaken subsidence over the eastern portion of the forecast area. Neither feature appears strong enough to produce a substantial pattern change locally, but moisture and convective coverage should increase slightly compared with today. Rain chances Saturday afternoon and evening will remain around 10 to 30 percent east of Interstate 55, including the Mississippi Gulf Coast and possibly the eastern New Orleans metro, with chances remaining below 10 percent near Baton Rouge and across the western CWA. A somewhat farther-west moisture plume or an eastern-Gulf outflow boundary could support locally higher coverage, but current support for that scenario remains limited.

Little additional change is expected Sunday. The Northeast trough will continue east while the eastern-Gulf weakness lingers, leaving the CWA near the transition between stronger ridging to the west and deeper moisture to the east. Isolated convection remains possible mainly along the Mississippi coast, east of Interstate 55, and over the eastern marine zones. PoPs will generally remain in the 10 to 20 percent range there and below 10 percent farther west. Weak steering flow could allow an isolated boundary-tied storm to move slowly or briefly redevelop, but the lack of storm coverage should preclude an organized training or flooding concern.

Heat will become increasingly concerning through the weekend. Highs Saturday and Sunday should range from the middle 90s to nearly 100 degrees. Heat indices will commonly reach 103 to 107, with values of 108 to 111 becoming increasingly likely along local interstate corridors. Overnight lows will remain in the middle and upper 70s inland and near 80 to the lower 80s in portions of metropolitan New Orleans and along the immediate coast, providing limited nighttime recovery. At least localized advisory-level heat appears increasingly possible for Saturday and especially Sunday. Have held off on Saturday for now as forecast is borderline.

MEFFER

LONG TERM

(Tuesday through Thursday night) Issued at 115 PM CDT Fri Jul 17 2026

The Northeast trough will eject eastward Sunday night into Monday while the south-central CONUS ridge expands eastward. Mid level heights should rise slightly over the lower Mississippi Valley and northern Gulf through at least Tuesday. With the residual eastern- Gulf weakness either lifting northeastward or becoming increasingly sheared and diffuse. This evolution favors continued below-normal summertime rain coverage. That's not to say that we won't see rain though. Still carrying 10 to 20 POPs Monday and Tuesday across most of the local forecast area but with higher probs eastern portions of the CWA. Any convection should remain isolated and tied primarily to the sea breeze or remnant outflow boundaries.

Heat should peak or become most persistent from Monday through at least Wednesday. Forecast highs are generally in the upper 90s, with an isolated 100-degree reading possible over inland areas if cloud cover remains minimal. Glancing at records, we may not break any but it surely will be really close, within a degree or 2 pretty much everywhere. Those highs with dewpoints in the 70s supports widespread heat indices of 105 to 110, with localized values above that. Repeated advisory-level heat appears increasingly likely and could even see an extreme heat warning issued one or 2 days next week.

Forecast confidence decreases somewhat from Wednesday through Friday. Most deterministic and ensemble guidance maintains substantial ridging over the central Gulf Coast, but there is spread concerning how strongly another Great Lakes or Northeast trough flattens the eastern side of the ridge aloft. There is also uncertainty over whether a weak mid level circulation or moisture axis remains over the eastern Gulf. The stronger-ridge solution would maintain very isolated convection and potentially prolong the most significant heat. A somewhat deeper eastern trough would allow for more typical afternoon sea-breeze convection and would provide localized relief from peak temperatures.

MEFFER

AVIATION

(18Z TAFS) Issued at 115 PM CDT Fri Jul 17 2026

VFR conditions will prevail through the 18Z TAF period. Only isolated shallow cumulus is expected this afternoon, with no appreciable probability of convection or a restrictive ceiling at any terminal. West to northwest winds will generally remain between 5 and 10 kt this afternoon before becoming light and variable or light westerly overnight. The dry and subsident column should prevent meaningful fog or low-cloud development Saturday morning.

MEFFER

MARINE

Issued at 115 PM CDT Fri Jul 17 2026

Surface high pressure centered near and just southeast of the Mississippi River mouth will maintain a generally west to northwest wind regime through the weekend. Winds will commonly be 5 to 10 kt over the tidal lakes and sounds, with 10 to 15 kt winds over the open Gulf waters. The northwest to north flow will be strongest during the overnight and morning hours before winds diminish during the afternoons. Seas should generally remain between 1 and 3 feet, although brief 2 to 4 foot seas will be possible over the eastern open Gulf waters Saturday. Thunderstorm coverage will remain very limited through Saturday. Isolated storms may reach the eastern waters Saturday night into Sunday as the eastern-Gulf upper low edges closer, but most of the marine area should remain dry.

Toward the middle of next week, the northern-Gulf surface high should weaken while the western extension of the Bermuda ridge becomes more influential. This should gradually relax the northwest gradient and produce lighter, more variable winds, eventually favoring a weak south or southwest component. The timing of that transition remains somewhat uncertain. Rain chances may also increase modestly over the eastern waters as deeper moisture returns, although widespread marine convection is not presently expected.

MEFFER

LIX WATCHES/WARNINGS/ADVISORIES

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