textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 622 PM CDT Sat Jul 18 2026

- A mostly dry pattern is expected into next week. The primary concern will be increasing heat. Heat indices will be in advisory criteria through much of next week. Urban areas could approach heat warning criteria Mon-Wed.

- Isolated to widely scattered thunderstorms will begin to develop mainly along and east of I55 during the late afternoon hours through the first half of the new week. Even though chances of storms will remain low, those that do develop could be strong to severe.

SHORT TERM

(Now through Tuesday night) Issued at 622 PM CDT Sat Jul 18 2026

Strong subsidence beneath the eastern periphery of the broad CONUS ridge continues to dominate local conditions early this afternoon. Radar remains essentially quiet, while visible satellite imagery shows very little meaningful cloud development across the region. However, worth noting CU streaks along the Pearl River Basin across southern MS is bears watching. The 12Z KLIX sounding supports overarching suppression, with a warm and comparatively dry layer through roughly 850-700 mb and north to northwest flow generally around 10 to 20 knots through the mid levels. High convective temperatures and deep mid layer dry slot should keep development very sparse. If a storm does develop, a brief strong downdraft cannot be completely ruled out , but organized severe weather is not expected.

The lack of appreciable clouds or rainfall will allow temperatures to climb into the mid and upper 90s across much of the area as the afternoon progresses. Dewpoints should mix down somewhat inland but remain high enough for heat-index values generally between 105 and 110 degrees. Overnight temperatures will only fall into the middle and upper 70s, remaining near 80 around the tidal lakes and immediate coast. This will provide limited nighttime recovery before another hot day Sunday.

An upper level trough moving from the Great Lakes into the Northeast will begin eroding the eastern periphery of the ridge tonight and Sunday. At the same time, the TUTT low and associated weak surface trough over the eastern Gulf should drift slowly west or northwest. There are at least a couple embedded MCVs which could influence the overall movement. For the CWA, we will remain on the western and northwestern, generally drier side of this circulation. However, its moisture envelope should begin edging far enough west to support a noticeable east-to-west gradient in convective coverage Sunday afternoon. POPs remain around 30 to 50 percent across coastal Mississippi, tapering to around 20-30% towards I-55. Rain chances fall quickly farther west, with only a very small chance around Baton Rouge and most locations west of I-55. Development should remain strongly tied to peak heating, the sea breeze, and any residual outflow boundaries. Convective times well into the 90s means late day initiation the farther west relative to the CWA. Storms over the far eastern CWA could produce locally heavy rainfall and brief gusty winds, but limited coverage and modest steering flow should prevent a broad heavy-rain problem.

A similar pattern continues Monday as the eastern Gulf circulation moves little or begins drifting toward the Florida Panhandle. The highest rain chances will again be across coastal Mississippi and the far eastern SELA parishes, generally in the 30 to 50 percent range, with substantially lower chances farther west. A farther- south or farther-west track would bring clouds and scattered convection somewhat closer to the New Orleans metro, but most guidance keeps the deeper moisture and more persistent convection east of the CWA. Whether the circulation briefly acquires subtropical or tropical characteristics is of less importance locally than its eventual track. At present, no meaningful local wind or coastal impacts are anticipated.

Outside of areas receiving an afternoon storm, highs Sunday and Monday will again reach the mid and upper 90s. Heat-index values of 105 to 110 degrees will remain common. Therefore, have already issued a heat advisory for tomorrow.

SHORT TERM

(Now through Tuesday night) Issued at 113 PM CDT Sat Jul 18 2026

Strong subsidence beneath the eastern periphery of the broad CONUS ridge continues to dominate local conditions early this afternoon. Radar remains essentially quiet, while visible satellite imagery shows very little meaningful cloud development across the region. However, worth noting CU streaks along the Pearl River Basin across southern MS is bears watching. The 12Z KLIX sounding supports overarching suppression, with a warm and comparatively dry layer through roughly 850-700 mb and north to northwest flow generally around 10 to 20 knots through the mid levels. High convective temperatures and deep mid layer dry slot should keep development very sparse. If a storm does develop, a brief strong downdraft cannot be completely ruled out , but organized severe weather is not expected.

The lack of appreciable clouds or rainfall will allow temperatures to climb into the mid and upper 90s across much of the area as the afternoon progresses. Dewpoints should mix down somewhat inland but remain high enough for heat-index values generally between 105 and 110 degrees. Overnight temperatures will only fall into the middle and upper 70s, remaining near 80 around the tidal lakes and immediate coast. This will provide limited nighttime recovery before another hot day Sunday.

An upper level trough moving from the Great Lakes into the Northeast will begin eroding the eastern periphery of the ridge tonight and Sunday. At the same time, the TUTT low and associated weak surface trough over the eastern Gulf should drift slowly west or northwest. There are at least a couple embedded MCVs which could influence the overall movement. For the CWA, we will remain on the western and northwestern, generally drier side of this circulation. However, its moisture envelope should begin edging far enough west to support a noticeable east-to-west gradient in convective coverage Sunday afternoon. POPs remain around 30 to 50 percent across coastal Mississippi, tapering to around 20-30% towards I-55. Rain chances fall quickly farther west, with only a very small chance around Baton Rouge and most locations west of I-55. Development should remain strongly tied to peak heating, the sea breeze, and any residual outflow boundaries. Convective times well into the 90s means late day initiation the farther west relative to the CWA. Storms over the far eastern CWA could produce locally heavy rainfall and brief gusty winds, but limited coverage and modest steering flow should prevent a broad heavy-rain problem.

A similar pattern continues Monday as the eastern Gulf circulation moves little or begins drifting toward the Florida Panhandle. The highest rain chances will again be across coastal Mississippi and the far eastern SELA parishes, generally in the 30 to 50 percent range, with substantially lower chances farther west. A farther- south or farther-west track would bring clouds and scattered convection somewhat closer to the New Orleans metro, but most guidance keeps the deeper moisture and more persistent convection east of the CWA. Whether the circulation briefly acquires subtropical or tropical characteristics is of less importance locally than its eventual track. At present, no meaningful local wind or coastal impacts are anticipated.

Outside of areas receiving an afternoon storm, highs Sunday and Monday will again reach the mid and upper 90s. Heat-index values of 105 to 110 degrees will remain common. Therefore, have already issued a heat advisory for tomorrow.

LONG TERM

(Wednesday through Friday night) Issued at 113 PM CDT Sat Jul 18 2026

The large upper ridge is forecast to remain centered near the Rockies through the period, with the CWA positioned beneath its southeastern periphery. The extent to which this ridge builds southeastward will determine both convective coverage and the magnitude of the heat. Meanwhile, a series of shortwave troughs passing through the Great Lakes and Northeast will periodically attempt to suppress heights across the southeastern CONUS.

Tuesday and Wednesday currently appear to favor a relatively strong southeastern extension of the ridge. The eastern Gulf disturbance should be lifting toward the Florida Panhandle or becoming increasingly diffuse by this time, leaving the deeper tropical moisture primarily east of the local area. Subsidence and high convective temperatures should consequently limit rainfall to isolated afternoon storms, with POPs generally no higher than 30 to 40 percent over the southeastern half of the local forecast area. Any storms that develop will be capable of brief heavy rainfall and gusty winds.

This may be the hottest portion of the forecast. Highs should reach the mid and upper 90s depending on site specific convection and cloud cover. Those temps with dewpoints in the mid 70s supports continued widespread heat-index values in the upper 100s to around 110, with localized readings above 110 possible. A period of extreme heat is well within reach of the current setup and forecast those days, especially in urban areas.

Forecast confidence decreases from Thursday into next Saturday as additional shortwaves cross the northeastern United States. Some guidance maintains a stronger ridge extension across the lower Mississippi Valley, which would preserve a hotter and mostly dry pattern. Other solutions weaken the southeastern edge of the ridge enough to allow a surface trough or weak front to settle toward the northeaster Gulf Coast. The latter scenario would support scattered diurnal convection. For now, low-end scattered PoPs in the 20 to 40 percent range appear reasonable.

AVIATION

(00Z TAFS) Issued at 622 PM CDT Sat Jul 18 2026

VFR conditions were in place at forecast issuance time and are expected to remain that way overnight. Isolated convection made it as far west as the Alabama-Mississippi state line this afternoon and produced a 33 knot gust at KPQL. Some potential for convection to develop a little further to the west tomorrow afternoon, and have indicated a PROB30 at KGPT for the afternoon hours. Can't entirely rule out storms making it as far west as KASD and the New Orleans terminals, but threat isn't high enough to carry in the forecast at this point.

MARINE

Issued at 113 PM CDT Sat Jul 18 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.

Isolated to scattered thunderstorms may spread into the eastern waters tonight through Monday as the eastern Gulf circulation drifts northward. The greatest coverage should remain east of the Mississippi River and especially near the Mississippi coastal waters. Any storms could produce frequent lightning, locally gusty winds, and briefly higher seas.

The local pressure gradient should relax by the middle of the week as the northern Gulf surface ridge weakens and broader Atlantic high pressure begins extending westward. This should support a more typical summertime pattern of light west to southwest winds generally around 10 knots or less. Late in the week, one or more shortwaves crossing the eastern United States may attempt to push a weak frontal boundary toward the northern Gulf. Confidence that the boundary reaches the coastal waters is low, but a farther-south progression could briefly turn winds northerly or northeasterly and produce a modest increase in speeds.

LIX WATCHES/WARNINGS/ADVISORIES

LA...Heat Advisory from 10 AM to 6 PM CDT Sunday for LAZ034>037-039- 046>048-056>058-064-070-071-076>087-089>100.

GM...None. MS...Heat Advisory from 10 AM to 6 PM CDT Sunday for MSZ068>071-077- 083>088.

GM...None.