Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
965 FXUS64 KLIX 180516 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1216 AM CDT Sat Oct 18 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .KEY MESSAGES... Updated at 1212 AM CDT Sat Oct 18 2025 - Marginal to possibly Slight Risk for severe weather tonight (Saturday night) for mainly north half of the CWA. - Showers and thunderstorms associated with tonight`s cold front likely to be the only precipitation during the 7 day period. && .SHORT TERM... (Today through Sunday) Issued at 1212 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 1212 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... (06Z TAFS) Issued at 1212 AM CDT Sat Oct 18 2025 VFR conditions in place for most terminals at forecast issuance, but there have been some clouds with bases around FL030 moving off the Gulf across southern terminals over the last 2 hours that the models aren`t really picking up on very well. Looking at observations, any MVFR ceilings have been very brief to this point. May make late decision to add ceilings there. The potential for IFR or lower conditions around sunrise may be diminishing with the clouds moving off the Gulf and some cirrus over top of them. Won`t rule it out, but confidence decreasing. Any lower conditions should quickly improve to VFR prior to 15z. Expect more high cloud cover on Saturday in advance of approaching cold front, but should be primarily VFR conditions during the day. Will carry PROB30 for SHRA/TSRA during portions of the afternoon hours at KBTR/KMCB/KHUM/KHDC, and during the evening at remaining terminals. TEMPO groups for TSRA will be primarily be beyond 06z based on most mesoscale and synoptic scale model solutions. && .MARINE... Issued at 1212 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 / 60 90 10 0 BTR 87 69 80 48 / 70 80 10 0 ASD 84 67 82 48 / 30 90 20 0 MSY 87 71 85 59 / 50 80 20 0 GPT 84 70 83 54 / 20 80 30 0 PQL 85 68 85 48 / 10 80 40 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RW LONG TERM....RW AVIATION...RW MARINE...RW