Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
000 FXUS64 KLIX 241647 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1147 AM CDT Fri Jul 24 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .KEY MESSAGES... Updated at 1146 AM CDT Fri Jul 24 2026 - Impactful heat conditions are likely to return this weekend and persist well into next week. && .SHORT TERM... (Now through Monday) Issued at 1146 AM CDT Fri Jul 24 2026 The transition back to a hotter and substantially drier pattern is underway across the region. Visible satellite imagery shows a fair weather CU field spread over LA and MS. Radar activity is confined mainly west of the forecast area over southwest/central Louisiana. The 12Z KLIX sounding sampled an unusually dry column for late July, with PW of only 1.46 inches which is near the 10th percentile for this time of year. The combination of limited column moisture, dry air aloft, and weak large-scale forcing should strongly suppress convection today. A very isolated shower cannot be completely ruled out over the Atchafalya Basin and northwestern portions of the CWA, where some CAM guidance continues to generate spotty activity. However, even that may be generous given the observed sounding. Temperatures are responding to abundant sunshine, with highs generally headed towards the mid 90s inland and lower to middle 90s near the immediate coast and tidal lakes. Heat indices should remain mostly below advisory criteria today, although values around 105 degrees will be possible where boundary-layer moisture remains highest and possibly even more localized to locations that measured rain yesterday. The broad scale upper ridge axis currenlty located near the 4 Corners will slide east to just east of the Rockies thru Sunday. At the same time, a surface high settles across the northern Gulf Coast. Warming through the 850-700 mb layer and increasing subsidence will strengthen the cap and further limit the usual afternoon convective relief. Rain chances will therefore remain around 10 percent or less both days this weekend, with only a rogue late-afternoon shower or storm possible along a sea breeze or other localized boundary. A light west or northwest low-level flow around that surface ridge will become increasingly important this weekend. This land-based surface flow regime should allow temperatures to rise rapidly each day before the sea and lake breezes can move far inland. Highs will climb into the middle and upper 90s Saturday, with upper 90s becoming more common Sunday as that upper ridge moves ever so slightly. If dewpoints remain in the middle or upper 70s during peak heating, heat indices will rise considerably despite the relatively dry air aloft. Thats probably the biggest limit of upper bound heat indicies on Saturday. Similar dewpoints on Sunday but with an incrimental increase in air temps will begin to bring more widespread 108+ heat index values across the CWA and see this as the first day of this forecast period that needs a heat advisory. MEFFER && .LONG TERM... (Monday night through Thursday) Issued at 1146 AM CDT Fri Jul 24 2026 The broad upper-level ridge centered to the northwest will remain the dominant feature across the south-central United States during at least the first half of next week. Mid to upper 590dm heights, strong subsidence, and a warm 850-700 mb layer will extend across southeast Louisiana and southern Mississippi. The primary driver of the heat will therefore be the combination of deep-layer warming, abundant sunshine, suppressed convection, and a persistent west to northwest low-level flow that delays meaningful marine influence during the hottest part of the day. Monday through Wednesday continue to appear to be the hottest portion of the forecast period. Inland highs will commonly reach the upper 90s, with some locations near 100 degrees. Did glance at record highs for early next week and forecast temps are right at to just below depending on location. Looking at model soundings for say New Orleans Monday, compared to this weekend, mid level winds shift to southeast. This helps in increase moisture in the surface to 700mb layer. What that does is instead of mixing drier air aloft to the surface, the higher surface dewpoints hold steady even during the afternoon hours. That`s how the pattern in place will potentially produce dangerous apparent temperatures. Peak heat indices of 110 to 115 degrees appear possible Monday through Wednesday. Heat Advisory criteria appears to be a given, based on persistent day-to-day model runs, with increasingly likelihood for portions of the I-10/12 corridors to approach Extreme Heat Warning criteria on one or more afternoons. Confidence is higher in a prolonged period of impactful heat than in the exact magnitude or placement of the highest heat indices. The duration of the event will become increasingly important. Overnight lows will remain in the upper 70s across much of the area and near or above 80 degrees around New Orleans, the tidal lakes, and the immediate coast. Looking at previous similar events, locations around the tidal lakes sometimes get such little relief overnight. Have seen periods where KNEW`s lowest heat index doesn`t even drop below 100! The poor nighttime recovery across the CWA will allow heat stress to accumulate as this event progresses. We see this in the HeatRisk guidance which shows Extreme for about 25% of the CWA Monday, ~70% of the CWA Tuesday, and 80-90% Wednesday. This is consistent with the combination of hot afternoons, warm nights, and very limited convective relief. And speaking of convection, strong subsidence from upper ridging aloft should hold rain chances to near 10% Monday through Wednesday. A rogue storm could still briefly develop along a sea breeze, lake breeze, or remnant boundary late in the afternoon, but meaningful or widespread relief is not expected. Most locations will remain dry each day. Global models suggest that Thursday and Friday will be the week`s downside of peak heat impacts locally as the eastern side of the ridge begins to weaken while troughing develops over the southeastern CONUS. An earlier breakdown would allow slightly greater afternoon convective coverage and shave a couple degrees from daytime temperatures. Given the uncertain timing, only a gradual easing of temps and a modest increase to slight chance POPs are warranted late in the period will possibly yield a more gradual breakdown of oppressive heat. MEFFER && .AVIATION... (18Z TAFS) Issued at 1146 AM CDT Fri Jul 24 2026 VFR conditions are expected through the period with only scattered afternoon CU and light winds. The probability of convection affecting any terminal is too low to have any mention of TAFs. Some guidance indicates the potential for 4-6sm vis around sunrise Saturday at KMCB. Confidence in restrictions is low, but a brief period of reduced visibility cannot be ruled out there. Otherwise, no appreciable aviation impacts are expected. MEFFER && .MARINE... Issued at 1146 AM CDT Fri Jul 24 2026 Surface high pressure building across the northern Gulf will maintain benign marine conditions today and Saturday, with winds generally around 5 to 10 knots and seas of 2 feet or less. The ridge will gradually shift southward this weekend, establishing a predominantly westerly flow regime from Sunday through the middle of next week. A typical summertime diurnal wind cycle is expected, with nocturnal winds increasing to around 10 to 15 knots during the overnight periods and early morning hours before relaxing closer to 5 to 10 knots during the daytimes. Seas will generally respond similarly, with 2 to 4 feet possible over the outer waters overnight and 1 to 2 feet during the day. Conditions should remain below headline criteria, although occasional gusts approaching 15-20 knots may occur over the outer waters during the stronger nocturnal wind periods and require an Exercise Caution headline. Strong subsidence aloft from upper level ridge influence will keep thunderstorm coverage very limited during all but maybe the end of the forecast period. MEFFER && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...ME LONG TERM....ME AVIATION...ME MARINE...ME