textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 530 AM CDT Tue May 19 2026

- Showers and thunderstorms will become more numerous and widespread Wednesday through the weekend. 7 day rainfall totals will range from 4 to 7 inches in the northwest to less than an inch of much of coastal MS and extreme SELA.

- Minor coastal flooding may slightly impact typically known problem areas like Waveland, MS today and Wednesday around midday.

- Temperatures are forecast to be generally near to warmer than normal through the next 7 days.

SHORT TERM

(Now through Friday) Issued at 112 AM CDT Tue May 19 2026

The upper pattern this evening shows a ridge along the Atlantic Coast with a trough from the Canadian Prairie Provinces to Nevada. At the surface, the Bermuda high extended westward across much of the northern Gulf. A frontal boundary was over the Plains States. Locally, skies were partly to mostly cloudy at midnight with temperatures in the mid and upper 70s and dew points in the mid 70s. Looks like summer has arrived.

Precipitable water values from the 00z upper air sounding across the region were in the 1.6-1.7 range, which is between the 75th and 90th percentile for mid-May. Those values don't really change much between now and Friday. What does gradually change is the track of upper shortwaves in the southwesterly mean flow over the next few days. The track of the impulse along the Texas coast this morning looks like it will remain mainly to the north and west of our area. So, similar to yesterday, soundings will support isolated to scattered convective development, but we don't anticipate organized convection this afternoon in our CWA. The nearest organized convection this afternoon looks like it will be in the Arklatex area. There is at least some potential for the Arklatex complex to develop a cold pool which could force it southeastward toward the local area this evening and overnight. If this does occur, it would have the potential to produce damaging winds, but that's a conditional threat and not a certainty. Coverage of convection yesterday was considerably less than what the NBM numbers indicated, and this looks to be true again today. Considering that, and the high temperatures from Monday, bumped forecast highs up a couple degrees for this afternoon.

Wednesday's shortwave exiting the trough will track a little closer to the local area, producing somewhat higher areal coverage of convection, and thus, slightly cooler high temperatures. By Thursday and Friday, shortwaves will be tracking just about over our area, with likely or higher PoPs looking justified. While there doesn't appear to be a great threat of severe weather beyond the next 24 hours, heavy rainfall will be the main or ongoing threat for the second half of the week. With precipitable water values remaining around the 90th percentile, and storm motions probably not much more than around 10 knots through at least Thursday, any areas that receive repeat convective cells could have issues with street flooding. The main threat area would look to be across the northwest, along and west of a McComb to Baton Rouge line. We'll take this day by day, but there's at least some potential we may need a Flood Watch at some point later this week.

There won't be much day to day change in temperatures with highs in the mid 80s to lower 90s that will be more determined by when precipitation occurs during the day in any one location. Convective temperatures will be pretty close to 90 every day, so that's a pretty decent starting point, but areas that see midday thunderstorms will fall a little short of that. Overnight lows will mainly be in the 70s, but if a cold pool develops with a complex of thunderstorms, that would knock lows down a bit.

LONG TERM

(Friday night through Monday) Issued at 112 AM CDT Tue May 19 2026

Through the weekend and into the start of the new workweek next week the region will remain on the western periphery of the H5 ridge over the northeast Gulf. This will keep the active southwesterly flow aloft overheard and will continue promote a wet pattern with little changes expected through the period. The main concern will be timing of H5 vorts as the move northeast within the flow. Overall, think the better rainfall chances will be during the afternoon hours where impulses may align with afternoon heating, but even during the off times there could still be some scattered convection possible. PWATS during this time will close in on 2.0 inches so cannot rule out localized flooding potential, especially west of I55 where the best ascent will be vs MS Gulf Coast closer to the 592dam ridge. Temperatures in the long term look to be held down just slightly due to higher POPs and cloudiness with most locations warming to around seasonal averages during the afternoon hours. (Frye)

AVIATION

(12Z TAFS) Issued at 530 AM CDT Tue May 19 2026

Mostly VFR conditions early this morning, although there are occasional patches of clouds as low as BKN007 at KBTR. At other terminals, it's closer to FL010 to FL020. As we get heating this morning, cloud bases will lift to FL025 to FL030 or perhaps a little higher. Areal coverage of SHRA/TSRA is expected to remain isolated through at least 21z, and not planning on any real mention prior to that point. Any organized TSRA would come from storms that would initiate well to the northwest. If they become cold pool dominant, there would be potential to reach at least our northwest (KBTR/KMCB/KHDC) terminals during the late afternoon or evening before dissipating. Will carry PROB30 for those. Low clouds and visibilities are possible toward sunrise Wednesday, especially if a terminal gets precipitation this afternoon/evening. Will mention IFR at KMCB after 09z Wednesday, and primarily MVFR elsewhere.

MARINE

Issued at 112 AM CDT Tue May 19 2026

A large area of high pressure will remain situated over the western Atlantic through the week and into the weekend. This will maintain light to moderate onshore flow through the time. Winds will bounce around headline criteria over the next 24 to 36 hours with sustained winds right around 15 kts, especially closer to the coast. Exercise Caution headlines will be in effect for the remainder of the night for the waters west of the mouth of the river along with Breton and Chandeleur Sound. As for showers and thunderstorms daily isolated to scattered light showers will be possible each day however the bulk of the coverage will remain inland. With any thunderstorm locally hazardous winds and waves can be expected. One last hiccup is maybe some very minor coastal flooding impacts, mainly around the Waveland area given the high astronomical tides and persistent southerly winds. Today midday may be the peak of any tidal impacts.

LIX WATCHES/WARNINGS/ADVISORIES

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