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189 FXUS64 KLIX 020904AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA304 AM CST Mon Dec 2 2024...New SHORT TERM, LONG TERM, MARINE....SHORT TERM...(Today through Tuesday)Issued at 300 AM CST Mon Dec 2 2024Large upper trough continues to be centered over the Great Lakesand Appalachians this morning, with ridging over the PacificCoast. A shortwave over northern California is trying to undercutthe ridge. This is producing northwesterly mid level flow acrossthe area. At the surface, high pressure extended from the Canadian Prairie Provinces to the Middle and Lower Mississippi River Valley. Skies were generally clear across the area at 3 AM CST, with a wide range in temperatures, from the mid 30s in the Pearl and Pascagoula River Basins, to the mid 50s in New Orleans with winds coming off the warmer waters of Lake Pontchartrain. The center of the surface high will continue to move southeastwardand be centered over Tennessee by Tuesday afternoon. This willkeep the local area in northeasterly surface winds for the mostpart, although a very weak sea breeze is possible very close tothe Mississippi Coast this afternoon, probably not much further inland than Interstate 10. With weak cold advection continuing atthe surface the next two days, can't see high temperatures gettingmuch warmer than what occurred yesterday, and maybe a coupledegrees cooler. That should still get most of the area into the60s today, and upper 50s to mid 60s tomorrow. Overnight lowstonight should be similar to this morning. Isolated freezingtemperatures can't be ruled out, but if they occur, it would be inareas that have already dipped below freezing a few times. Notanticipating a Freeze Warning being issued at this time.&&.LONG TERM...(Tuesday night through Sunday)Issued at 300 AM CST Mon Dec 2 2024The shortwave over northern California this morning willeventually close off over Arizona and New Mexico by midweek. Thiswill briefly produce a split mid level flow across the easternhalf of the country. The local area will be in the southern streamof this flow, with a shortwave moving across the area Wednesdaynight and Thursday. That portion of the forecast is fairlystraight forward, as surface high pressure moves to Florida,placing the local area in onshore flow for Wednesday intoThursday. Precipitable water values climb to the 1.5 to 1.6 range,which is near or above the 90th percentile climatologically. Raincould break out across the area as early as late Wednesdayafternoon, but is most likely overnight Wednesday night intoThursday morning. Clouds will increase ahead of that on Wednesday,with the question of high temperatures dependent on how quicklythat occurs. Instability is rather lacking, so probably not much more than some embedded thunder. Rain amounts of an inch or two would be what we expect out of this system. We've been dry across much of the area since November 19th, so some rain might actually be welcome. Beyond the frontal passage, the operational medium range guidancestarts to exhibit some differences, with the 00z GFS hanging thefrontal boundary along the Louisiana coast, while the 00z ECMWFpushes it well offshore, with cold, dry advection across a goodportion of the area. The operational temperature guidance exhibitsa 15F or more difference in some locations Friday into Saturday.Looking at the GFSBufr soundings for the end of the week, they'dactually support temperatures a good bit closer to the ECMWFcolder numbers. It's a situation where 50-100 miles difference infrontal location is the difference between Friday morning lowsbeing near freezing on the north shore vs lows in the lower 50s. The GFS solution would hold rain chances in the forecast from lateWednesday through Saturday night before drying out. The ECMWFwould be essentially dry for Thursday evening into most of theweekend, before another chance of rain Sunday. At this point,without a consensus solution, the NBM deterministic is the "safe"bet as a forecast solution, with an expectation that changes willbe necessary as the actual solution becomes more apparent. &&.AVIATION...(06Z TAFS)Issued at 1122 PM CST Sun Dec 1 2024No visibility or ceiling concerns for all terminals for the wholeforecast period. -BL&&.MARINE...Issued at 300 AM CST Mon Dec 2 2024Will institute Small Craft Exercise Caution headlines for thewestern open waters today with forecast package issuance. Whilewind speeds may occasionally creep above 15 knots elsewhere, thearea under the headline will more confidently be in the 15 to 20knot range today. Similar conditions will be possible Tuesday into Tuesday night over the same area. The next frontal passage on Thursday may lead to Exercise Cautionheadlines or Small Craft Advisories Thursday night into Friday,depending on the location of the frontal boundary. &&.PRELIMINARY POINT TEMPS/POPS...MCB 62 33 56 33 / 0 0 0 0 BTR 67 39 64 40 / 0 0 0 0 ASD 64 37 61 37 / 0 0 0 0 MSY 62 45 59 46 / 0 0 0 0 GPT 63 38 59 38 / 0 0 0 0 PQL 66 34 62 34 / 0 0 0 0 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...None.GM...None.MS...None.GM...None.&&$$SHORT TERM...RWLONG TERM....RWAVIATION...BLMARINE...RW
