


Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
773 FXUS64 KLIX 181147 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 647 AM CDT Sat Oct 18 2025 ...New AVIATION... .UPDATE... Issued at 638 AM CDT Sat Oct 18 2025 A moisture convergence band has induced some light to moderate rain shower activity in a north-south orientation stretching from the Pearl River drainage southward across eastern portions of metro New Orleans and into coastal Louisiana over the past hour. These showers will persist for a few more hours before dissipating as convergent band weakens. Pop, weather, and QPF forecast has been adjusted through mid-morning to reflect the ongoing conditions. && .SHORT TERM... (Today through Sunday) Issued at 638 AM CDT Sat Oct 18 2025 Upper ridging centered over the Appalachians with an upper trough from Ontario Canada to the Four Corners region. At the surface, low pressure over western Ontario had a frontal boundary southward to the Kansas-Oklahoma border, then southward into west Texas. Onshore flow during the day definitely added moisture to the airmass with evening surface dew points mainly in the upper 60s to around 70, about 5 degrees higher than the same time Thursday evening. Precipitable water values jumped from about 0.9 inches Thursday evening to about 1.35 inches 24 hours later. The upper trough over the Rockies during the evening will move eastward over the next 48 hours, crossing the local area between midnight and sunrise Sunday, with the frontal boundary moving across the area prior to sunrise Sunday as well. The low level onshore flow will continue to pump moisture into the area, especially during the afternoon hours, with precipitable water values approaching 2 inches, which would be somewhere around the 95th percentile climatologically. Airmass will become unstable, but not exceedingly so, with lifted indices in the -3 to -5 range and mid level lapse rates in the 6 to 6.5 range. The 0 to 1 km and 0 to 2 km SRH values are expected to be around 200. While none of these are extreme values, they also are worthy of at least monitoring the situation. The primary threat would likely be damaging winds, but considering the low level helicity values, a few tornadoes certainly can`t be ruled out. Wouldn`t be surprised if there is a little patchy fog this morning, but it should burn off pretty quickly, especially once winds pick up a little. Isolated convection could occur as early as late afternoon, but the main line of thunderstorms may not move into our CWA from the northwest until right around midnight, give or take an hour or two. Current indications are that most or all precipitation will be east of the area by sunrise Sunday. With the extremely progressive trends in the guidance, this doesn`t look to be a major rain producer on the large scale, with areas seeing less than an inch, possibly much less. Skies should clear pretty quickly Sunday with rapid drying expected. Dew points that will be in the 65 to 70 degree range just ahead of the cold front will likely be in the mid 40s to mid 50s Sunday evening. Precipitable water values will similarly fall from around the 90th to 95th percentile to the 10th or lower (0.4 to 0.5 inches). High temperatures are likely to be in the mid and upper 80s both days, but Sunday could actually turn out the warmer of the two, although with much less humidity, for areas from about the Pearl River Basin eastward. Quite frequently, behind a cold front with northwest or north winds, those areas tend to heat up a bit more due to weak compressional heating. Wouldn`t be a total shock if somewhere between Hammond and Pascagoula touches 90 Sunday afternoon. && .LONG TERM... (Sunday night through Friday) Issued at 638 AM CDT Sat Oct 18 2025 Cooling behind the frontal passage will be very noticeable. Low temperatures Monday morning are likely to be 15 to 20 degrees cooler than Sunday morning. Highs Monday will struggle to reach 80 degrees, which is actually pretty close to normal. We`ll need to keep an eye on dew points Monday afternoon, as they could drag minimum RH values fairly close to critical levels across the north half of the area (<30 percent). As a shortwave moves through the middle Mississippi River Valley Tuesday, it will bring a reinforcing cold front across the area, but might not produce more than a few sprinkles of rain. High pressure behind that front should keep the remainder of the workweek dry. Highs are likely to be in the upper 70s to mid 80s for much of next week with lows primarily in the 50s, although Thursday morning could see lows in the 40s in normally cooler areas. As a comparison, normal highs for next week should be in the upper 70s with lows in the 50s. && .AVIATION... (12Z TAFS) Issued at 638 AM CDT Sat Oct 18 2025 Brief periods of rain associated with a moisture convergence band will impact ASD, NEW, MSY through 14z. The rain is light, so no significant visibility concerns are expected. The convergence band will weaken after 14z, and prevailing VFR conditions will take hold at all of the terminals. After 19z, scattered storms will start to develop near HUM and BTR, and a threat of MVFR conditions as these showers move through is reflected with PROB 30 wording from 19z to 01z. The convective activity will spread to the rest of the terminals after 01z with occasional MVFR ceilings and visibilities reflected by PROB30 wording. After 06z, a stronger line of thunderstorms in advance of a passing front will impact most of the terminals with gusty winds and IFR visibilities. The line of storms should clear GPT by the end of the forecast period. MCB, BTR, HDC, ASD, GPT, and NEW are most likely to affected by the line based on the latest high resolution model solutions. Given this, MSY and HUM only have a mention of rain over this period. After the line of storms and associated front moves through the terminals, a period of post-frontal IFR stratus will linger at all of the terminals for a few hours. PG && .MARINE... Issued at 638 AM CDT Sat Oct 18 2025 High pressure has moved east of the area, and winds are now southeasterly. Winds will remain not much more than 15 knots ahead of a cold front that is expected to move through the coastal waters by midday Sunday. May eventually need a Small Craft Exercise Caution headline for tomorrow night for some of the open waters, but won`t go with one this package. After the front moves through, winds will shift to the northwest, but choppy conditions will persist. Winds and waves should subside on Monday as high pressure moves in. && .PRELIMINARY POINT TEMPS/POPS... MCB 85 66 76 47 / 40 70 0 0 BTR 87 69 80 48 / 50 60 0 0 ASD 84 67 82 48 / 20 70 10 0 MSY 87 71 85 59 / 30 70 0 0 GPT 84 70 83 54 / 10 80 50 0 PQL 85 68 85 48 / 20 80 70 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RW LONG TERM....RW AVIATION...PG MARINE...RW