Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
102 FXUS64 KLIX 060753 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 253 AM CDT Sun Sep 6 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .KEY MESSAGES... Updated at 249 AM CDT Sun Sep 6 2026 - Scattered to numerous showers and storms are forecast throughout the forecast period. The overall severe weather threat will be low, but one or two storms could become strong to severe. - Primary threats with storms will be strong wind gusts, frequent lightning and periods of heavy rain leading to localized flash flooding. - Above normal temperatures expected most of the 7-Day forecast period. Afternoon heat indices will generally range from 100 to 108 degrees. && .SHORT TERM... (Now through Labor Day) Issued at 249 AM CDT Sun Sep 6 2026 A fairly typical late summer pattern remains in place this morning with the forecast area positioned along the south to southeastern periphery of a mid level ridge centered over the central Plains. Meanwhile, troughing remains east of the region. For today, convection should initially be tied to the usual sea breeze and other mesoscale convergence boundaries as temperatures warm through late morning and early afternoon hours. Coverage should be greatest across the southern half of the area from coastal Louisiana through the New Orleans metro and Mississippi coast, while storms farther north toward Baton Rouge and southwest Mississippi may be a little more dependent on outflow boundaries spreading away from earlier convection. There is also enough support among the CAMs for a weak convective complex to approach the area from the north late this afternoon or early this evening. Confidence in the survival and exact track of this feature is not particularly high, but it is enough of a signal to avoid going too low with PoPs late in the day. Should this complex hold together, convection would become more widespread than a pure sea breeze regime and could persist somewhat later into the evening. The thermodynamic environment continues to favor primarily pulse or loosely organized multicell convection. With a very moist column, a classic deep inverted-V profile is not the primary signal today, but strong heating can still steepen low level lapse rates and develop enough sub-cloud drying for water-loaded downdrafts. Thus, one or two storms could produce strong to marginally severe wind gusts, particularly where convection develops after several hours of uninterrupted heating or along the leading outflow of any approaching cluster. Weak shear should keep the overall organized severe threat low. Deep moisture remains in place locally with PW values generally around 2.1 to 2.3 inches. This should continue to favor greater convective coverage than some of the less aggressive CAM solutions would suggest and put heavy rainfall as more probable than severe wind gusts. That high PW environment and deep warm-cloud layer will support efficient rainfall rates, while generally weak steering flow will allow individual cells and boundaries to move rather slowly. Repeated development along a sea breeze or stalled outflow boundary could produce brief training or backbuilding. Most locations will simply see a heavy downpour, but localized street flooding and an isolated flash flood issue remain possible, especially in urban areas or locations that receive multiple rounds. Temperatures should again climb into the lower to middle 90s away from the immediate coast before convection develops. With dewpoints remaining well into the 70s, peak heat indices should generally reach the lower to middle 100s, with a few locations potentially flirting with 108 degrees if storms are delayed. Convective timing is the limiting factor for a more widespread heat concern, as an earlier start or the arrival of the aforementioned convective complex would quickly cut into both temperatures and heat indices. By Monday the upper trough to the east edges a little closer and attempts to drive a backdoor front toward the area. The front itself still appears unlikely to make meaningful progress into the CWA, probably stalling across southern Alabama or very near southeast Mississippi. Its proximity and the associated weakness aloft should be enough to reduce subsidence along the eastern side of the ridge, however, allowing another fairly healthy round of diurnal convection. Sea breeze and remnant outflow boundaries should again provide the primary low level forcing. There is some indication in forecast profiles that drier air may mix down into southwest and coastal Mississippi Monday afternoon. This would favor dewpoints somewhat lower than blended guidance there and could shave several degrees off peak heat indices despite another warm afternoon. At the same time, the slightly drier sub-cloud layer could modestly improve downdraft efficiency with any stronger storms. Otherwise, the same general hazards continue Monday: locally strong wind gusts and very efficient rainfall from the stronger convection, with localized flooding possible where storms repeatedly affect the same location. MEFFER && .LONG TERM... (Tuesday through Saturday) Issued at 249 AM CDT Sun Sep 6 2026 The ridge remains influential Tuesday, but the pattern should begin a gradual transition as its center settles farther south and east from where it is to towards Arkansas while northern stream troughing starts to flatten the northern side of the ridge. Enough subsidence should remain to keep convection largely diurnal rather than an all- day affair, but the combination of residual deep moisture, weak shortwave riding the periphery of the ridge and the nearby stalled boundary should support at least scattered to possibly numerous afternoon storms. Coverage may remain somewhat greater across southeast Mississippi and the eastern half of the area where the influence of the ridge is weakest. Tuesday and probably at least part of Wednesday should remain warmer than normal with lower to middle 90s common before convection develops. Heat indices will again reach the lower to middle 100s, and localized values near Heat Advisory criteria cannot be ruled out. However, this continues to be a marginal setup for actually meeting criteria over a meaningful area and duration, since the locations with the highest dewpoints will also generally have the better opportunity for earlier convection. By Wednesday into Thursday, the northern stream trough becomes more effective at suppressing and flattening the ridge. As heights fall and subsidence weakens, convective coverage should gradually increase. This still does not look like continuous rainfall, but increasingly numerous diurnal showers and thunderstorms become more plausible, especially where any weak surface boundary or convective remnant provides additional focus. With plenty of moisture remaining, locally heavy rainfall will continue to accompany storms. The trend becomes more pronounced Thursday into Friday as troughing presses farther south and the ridge has considerably less influence over the local area. This should favor an earlier convective start and greater overall coverage, which in turn argues for temperatures trending downward. Would favor highs closer to seasonal normals during this portion of the forecast rather than holding onto the warmer end of guidance, particularly on days where convection begins before peak heating. && .AVIATION... (06Z TAFS) Issued at 249 AM CDT Sun Sep 6 2026 VFR conditions prevail initially with light winds. KMCB remains the terminal most susceptible to VIS restrictions toward daybreak, where mist and developing low stratus could produce a period of MVFR and possibly brief IFR ceilings. Elsewhere, widespread significant restrictions are not expected early this morning. A CU field should begin developing across the region around 14-15Z with bases initially near MVFR thresholds in spots, then lifting into VFR as the boundary layer warms. Scattered afternoon thunderstorms are expected, with the greatest confidence in impacts from KHUM through KMSY and KGPT. PROB30 TSRA groups remain appropriate for those terminals generally during the 18-24Z period. Coverage around KBTR, KMCB and KASD looks more isolated and confidence in direct terminal impacts is too low for a PROB30 at this time. Any thunderstorm could briefly produce IFR visibility, lower ceilings and strong/erratic wind gusts. A weak convective complex approaching late in the day remains a lower confidence possibility and could prolong terminal impacts into the early evening. MEFFER && .MARINE... Issued at 249 AM CDT Sun Sep 6 2026 The pressure gradient will remain weak through the period with generally benign background marine conditions. Winds should mostly remain around 10 knots or less with seas around 1 to 2 feet through the short term. The primary marine concern will continue to be thunderstorms. Deep moisture remaining over the northern Gulf will favor scattered convection over the coastal waters, particularly during the late night and morning hours before the focus shifts inland with the sea breeze during the afternoon. Coverage should remain elevated through Monday as the upper trough approaches and weakens subsidence, despite the backdoor front likely remaining east of the local waters. Daily thunderstorm chances continue through the remainder of the week and may increase somewhat late in the week as the upper ridge weakens and troughing becomes more influential. Outside of convection, conditions should remain well below advisory criteria. The stronger storms will remain capable of locally gusty winds and briefly higher waves. MEFFER && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...ME LONG TERM....ME AVIATION...ME MARINE...ME