textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 445 AM CDT Sun Jul 19 2026

- A mostly dry pattern is expected through this week. The primary concern will be increasing heat. Heat indices will be in advisory criteria through much of the 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 this week. Even though overall coverage of storms will remain low, those that do develop could be strong to severe.

SHORT TERM

(Now through Wednesday) Issued at 1057 PM CDT Sat Jul 18 2026

We will discuss the sfc low over the NE gulf, but the main issue for our area is strong heating through much of this week. It is possible that heat warnings will be placed for some areas over the coming days. Most of the area sits on the outer envelope of the convective blowups going on just to our east. The air from this vertical circulation sinks over our area causing the air to compress and heat up even more. The light winds produced between the sfc low to the east and the sfc high to the west is northerly bringing preheated air off the landmass as well. There will be some chances for storms to develop giving some relief, but they will not be widespread and best chances are to the east leaving most of the area dry and hot. The storms that do develop will be late in the day after the strongest heating has developed, so eventhough relief could come for very few areas, it will only be after the hottest part of the day has gone by.

The weak sfc low that was in the SE gulf last night is now over the NE gulf where it will stall this morning through this evening. Even when it does start meandering northward again by Monday, it will be very slow. NHC decided to move upward with chances of formation. This system has been a broad circulation for at least a day. This does not mean it is a tropical cyclone, but it is a broad circulation with no real organization. There are seveal reasons we can look at this and say it is not a clear cut tropical entity yet. One fact is that it is a vertically stacked low since it is fighting a TUTT low and will continue to do so. There is a roughly 48 hour window that winds aloft will weaken enough to allow the sfc low to strengthen, which starts around noon today through Tue morning. This is likely why the odds of this developing increased. Even that time frame will exhibit some complications for the system. A strong environment for tropical development would have the mass of convective development and pulsing over the sfc circulation and to its east through south. This system has the most development on its west side. This does eventually try to wrap around to its south then east, but it is late in the game by that time. WV imagery shows some strong dry air intrusion moving into the system from the NE as well, but that also weakens with time. The troughing producing the storms on the west side of the system arcs from GA to Mobile into the gulf and bends back around to the south side of the sfc low. This is the trough that eventually and slowly sneaks westward giving the eastern portion of our area higher sh/ts chances. Weak sfc lows can be dragged into areas of expolsive convective development and/or a convective pulse(explosion) can and does create its own mesovortex which can also become a sfc low. This is why the area of tropical development odds are around and far west of the "X" on NHC's maps. Regarless of development odds, the low will likely remain weak but some impacts from this will be strong/severe storms over land and marine and heavy rainfall. This will hold true for our area as the westward progression of this deeper moisture field reaches us. Since these storms are developing in some strong heating, they would have a higher potential to become strong or severe. But they will be moving at a good pace, so other than nuisance flooding is not expected. Most of this will take place in coastal Miss. But areas east of I55 will have some odds of getting a storm or two through mid week. By Tue into Wed, this broad circulation is somewhere along the coast which could be from the Pearl River to Pensacola as a cold front digs into the SE CONUS picking up a good bit of its moisture.

LONG TERM

(Wednesday night through Saturday) Issued at 1057 PM CDT Sat Jul 18 2026

Medium range operational models generally agree on the larger scale pattern Wednesday night with the upper ridge centered near the Oklahoma-Texas border north of Dallas, and an upper trough across the northeast quarter of the country.

Beyond that point, the question becomes how much northern stream shortwaves moving down the east side of the ridge erode the southeast extension of the ridge. A stronger shortwave could erode the extension enough to allow a weak frontal boundary into the area and increase rain chances (and lower temperatures a little). At present, there doesn't seem to be much change in the pattern until at least next Saturday. There's not enough difference in PoPs between the operational models to make significant adjustments. Would note that on the 18/12z ECMWF, the operational PoPs were pretty close to the wettest member of their ensemble.

Rain chances will drive the high temperature forecast. Without rain, it's entirely possible that the current forecast isn't high enough late in the week. Heat Advisories and/or Extreme Heat Warnings can't be ruled out on any day through the end of the workweek.

AVIATION

(12Z TAFS) Issued at 445 AM CDT Sun Jul 19 2026

The only terminal that has any real chance of TSRA today will be GPT. PROB30 group will be used to time this for today. Otherwise, VFR through this taf cycle at all sites.

MARINE

Issued at 1057 PM CDT Sat Jul 18 2026

A weak surface low over the northeast gulf and a surface high over the northwest gulf will maintain a northerly flow over the north central gulf through the first half of this week. As the low moves north, winds will eventually become westerly by mid week. Wind speeds will generally be 10 to 15 knots for most of the coastal waters but well offshore winds could approach 15 to 20 knots for short periods. Thunderstorm coverage will increase over the waters east of the Miss River today with a steady westward penetration over the next few days. Winds and seas will rapidly rise in and around thunderstorm activity.

LIX WATCHES/WARNINGS/ADVISORIES

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

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

GM...None.