textproduct: New Orleans/Baton Rouge

KEY MESSAGES

Updated at 1044 PM CDT Tue Jun 30 2026

- Heat index values will be in the 105 to 110 range for most areas today and a heat advisory has been issued. Those with outdoor plans or work should take precautions to avoid heat- related iillnesses. Drink plenty of water, wear light- weight and loose- fitting clothing, and take breaks in the shade or air conditioning during the afternoon hours.

- Daily scattered to numerous showers and storms with the highest chances today. Widespread severe weather and heavy rain will be low, a few storms each day could become strong to severe gusty winds and/or locally heavy rainfall. The potential will exist for waterspout and tornado activity as well.

SHORT TERM

(Now through Friday night) Issued at 1044 PM CDT Tue Jun 30 2026

Storms quickly decayed as the evening progressed which tells us heating was the main driver. Still some storms moving across the coastal waters which are still getting some heat from the marine areas as they are now quite a bit warmer than land areas. Some of the highest SST are New Canal at 91F and Grand Isle at 89F. This is in the ball park of even land convective temps but very close to marine convective temps. The summer months are more unstable overnight, on average, for marine areas than land and vice versa for winter months. And the opposite is true for daylight hours. This is very general since other factors matter a great deal and timing even on normal summer days for these differences is from about noon to midnight each day. This does seem confusing when trying to learn it, and it is at first, but it is a great tool to have when fcasting normal summer diurnal convection. This easterly wave did not bring convective temps completely down to SST levels at our coastline yesterday but if this has occurred this morning we should see a few storms light up fairly quick this morning over the warmest shallow waters. The 12z sounding will also tell us if it did this morning. But the wave was able to get these temps within a few degrees and most likely reached them farther offshore. This means that where convective temps are higher, at the most northern part of the wave, unless there is ongoing activity or an outflow boundary helping the forcing, there likely wouldn't be more development. So, as the old outflow from the decaying complex moves over the coastal lakes and nearshore waters, there could be some rapid development this morning. Where these temps match or are lower than SST numbers, there will also be more storms develop this morning even in the absence of additional forcing(outside bouancy). The majority of storms today should be over the western half of the area for good reason, this is where the easterly wave will be today. But the remainder of the area has been placed into lower convective temps relative to what we have seen over the past several days, so there will also be some activity over the eastern half as well, just not as numerous. Any of this could produce strong/severe wind gusts and heavy rainfall, but storm cells will be moving around 25mph to the west then eventually NW, so they won't be in one location for a long time. The wave is bringing us back into a very normalized summer regime where 30-50% precip numbers are popular and ofcourse the summer heat and humidity that goes along with it. This will be the bulk of the fcast past today, at least through the end of this work week.

The area that was being watched over the Atlantic(upper low vortex) has been dropped for good reason. But we will let you know where this feature is going over the coming few days. The upper low has warmed a bit over the last 24 hours which how these things start to become more barotropic and not baroclinic. The upper low will move west today and should be near or just moving into the upper NE Florida coast by late this evening. A strong dry air surge will get forced into it as it moves west which keeps this very weak and unorganized. The low slowly moves farther west over the FL panandle and then northward into the SE CONUS as we move into the end of the week where it opens into the base of the next long wave upper trough. It is easier to see this in the modeled H3 wind field.

LONG TERM

(Saturday through Monday) Issued at 1044 PM CDT Tue Jun 30 2026

By Saturday, the ridge will begin to weaken and move eastward allowing a weakness in mid-level flow and lowering of heights over the area. This could locally enhance afternoon PoPs once more over the weekend with more scattered to numerous storms on Sunday especially as a reinforcing weak shortwave moves down across the lower Mississippi Valley. With weak flow aloft, model guidance gets increasingly more uncertain regarding more subtle shortwave troughs and ridges into early next week which will provide more nuanced influences on temperatures and PoPs each day. However, the general idea will still be for largely climatolgoically normal conditions through early next week.

Looking ahead, the longwave pattern within the global ensemble guidance continues to suggest the potential for a larger mid-upper ridge setting up over the west-central CONUS and favoring troughing and west-northwest flow aloft across the southeastern CONUS headed into next week which could bring temperatures down and potentially bring more convective activity into the area by late next week.

AVIATION

(06Z TAFS) Issued at 1044 PM CDT Tue Jun 30 2026

Outside TSRA, VFR should be the rule for this taf cycle. There will be the possibility that sites receive IFR conditions with passing TSRA today and these will be timed for each location. The highest probs will remain along and west of a line from MCB to MSY to Grand Isle. Storms will be moving east to west and a few of these could produce strong shear from downbursts.

MARINE

Issued at 1044 PM CDT Tue Jun 30 2026

Generally isolated to scattered showers and storms can be expected each day, with potential for more numerous/widespread convection today associated with the easterly wave. A few stronger storms could produce gusty winds and/or waterspouts, and locally hazardous seas during the second half of the work week. The northern gulf will be dominated by high pressure after Wednesday. Winds will generally be 10kts or less and direction will vary through midweek, becoming more predominantly southerly as high pressure builds over the eastern Gulf late in the week.

LIX WATCHES/WARNINGS/ADVISORIES

LA...Heat Advisory from 10 AM to 6 PM CDT Wednesday 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 Wednesday for MSZ068>071- 077-083>088.

GM...None.