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301 FXUS64 KLIX 061103AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA503 AM CST Mon Jan 6 2025...New SHORT TERM, LONG TERM, AVIATION, MARINE....SHORT TERM...(Today through Tuesday)Issued at 321 AM CST Mon Jan 6 2025Line moved through overnight about as expected with it really losing its potency after it crossed I-55 while the cold frontcontinued to sweep through the area. Much colder temperatures werequickly infiltrating the area from the northwest post frontalpassage while strong northwest winds continued. The very cold airis still back to the northwest but it is making its way towards the region and we should still see a large chunk of the CWA drop into the upper 20s to mid 30s before 14z. That along with winds of10-20mph and higher gusts should easily get wind chill values in the upper teens to mid 20s for most of the area currently in the Cold Weather Advisory.If you absolutely hate the cold the next week and honestly couldbe much of the month will not be a welcome sight. Through at leastThursday highs are likely going to range 15 to 20 degrees below normal with morning lows around 10 to 15 degrees below normal.Why, well we have finally tapped into the Arctic air to the northas it surged down the Plains. Over the next 3-4 days we will see aL/W trough develop and dig to our west with the base digging intothe Baja and deep southwest flow becoming entrenched over the area tomorrow and through the week. This will at the least keep usfrom moderating much as we should see persistent mid and upper lvl cloud stream in from the west and southwest tomorrow through Thursday night. The other issue is we will get another system latethis week as a sfc low begins to develop in the western Gulf but more on that in the extended. Today through Tuesday night...cold and breezy. locations along andsouth of I-10 will finally have a rather decent chance of gettingbelow freezing this season. That said the winds are not expectedto completely decouple and honestly in these more Arctic style airmasses we generally don't completely decouple. CAA won't necessarily be strong still tonight but it will continue through today and into tonight and that will be able to compensate for poor radiational cooling conditions tonight. That other problem tonight is wind. Winds will not be anything like yesterday or evenwhat is currently happening but any wind will make it feel much colder, even as little as 5-7 mph. As for tonight winds will likely be around 6 to 12 mph even gusting to near 15 mph away fromthe coasts however right along the coasts and especially across the Southshore and even St Bernard and Plaquemines parishes winds could still be gusting to 20-25 mph at times. Even though the temps into most of these areas won't be nearly as cold thanks to some slight modification from the water the wind will make up for that allowing the wind chill readings to drop to 25 or cooler. With those values expected we have issued another Cold Weather Advisory (CWY) for the entire forecast area tonight. What about freeze warnings, as mentioned yesterday we will not issue Cold Weather Advisory and Freeze Warnings concurrently for the same zones/parishes/counties. The freeze warnings now are generally just light freeze and don't cause problems for pipes. If the windswere lighter then a freeze warning would be issued for areas along and south of the I-10 corridor but given the wind chill readings are expected to be below 25 for much of that area the greater concern is the impacts on people and pets and the Cold Weather Advisory is the more appropriate product and takes precedence. Heading into Tuesday night and Wednesday morning high pressureshould be a little more entrenched into the area. This is likelygoing to help winds back off significantly. The winds likely won't go calm still but should not be anything abv 6-7 mph outside of the immediate coast and even winds in those areas will be much weaker. With that the wind chills values expected to be inthe upper 20s to lower 30s for area south of I-10 but morning lowsare expected to also drop to near and just below freezing. Withthat a Freeze Watch may be issued later today for Tuesday night. Iwould issue it now but with 2 Cold Weather Advisories already outI would rather let the current one end this morning before addinganother headline and possibly creating unnecesary confusion.Forecast begins to get a little interesting as we get intoWednesday night and through the rest of the work week. /CAB/&&.LONG TERM...(Tuesday night through Sunday)Issued at 321 AM CST Mon Jan 6 2025Models continue to really struggle with the details on how thingswill evolve later this week. That said they have honestly beensomewhat consistent in the broad scope and with the setup that isin place small changes in track, timing, and strength willabsolutely mean very large changes to possible impacts. The trendover the last 24 hours has been a touch south with the sfc low later this week. The operational models are rather close keepingthe sfc low along or just south of the coast now while theensemble means are a touch farther to the south. The main issue here is how the closed mid lvl low over the Bajaplays out as it tries to phase with the L/W trough. The trend overthe last few days has been to keep the base of the trough hangingback to the southwest through Mexico and across the Baja. Thisslow deeper L/W trough would suggest a farther south sfc low. Wewill need to watch this closely because if this trend continues tothe sfc low trends a little more south then there is a legitimateshot of some winter precip possibly leading to impacts. Forecastsoundings at this time continue to suggest the only winter precipwe would see would be a mix of -fz/-sn/-ra at the very onsetThursday morning across southwest MS and that would last for maybe30 mins before we transition to all liquid. But there is the potential for greater impacts if this sfc low is a little farther south. There will be moderate WAA in the LL abv the sfc (not necessarily a TROWAL) but definitely a LL jet transporting deeper moisture well north and NNW of the developing sfc low providing increasing lift and the fcst soundings are indicating pretty strong lift in the dendritic layer which would lead to heavy precipitation. With the current low track none of that matters as we will be well abv freezing and even with evaporative cooling we would not wet bulb cold enough. If the sfc low is farther south there is a chance we would be a little deeper into the cold air and that would then provide slightly better potential for some wintry precip Thursday and possibly into Thursday night but that is a very low chance right now. The greater concern looks like locally heavy rain. With deep southwest flow aloft, very strong forcing from a mid lvl jet thatcould be approaching 100 kt, the developing LL jet providingstrong LL convergence and directly over the CWA, broad divergencealoft, PW's that could rebound to around 1.5", and a sfc low tracking slowly across the coast; the potential is there for a band of heavy rain across the region. Total rainfall potential from Thursday through Friday could be 2-3 inches with locally higher amounts. That is not a low but most of that could fall in a6-12 hr window sometime between late Thursday and early Friday. Combine that with rather cold temps the days leading to ground that is cold and not ready to soak up a lot of rain and we have the recipe for runoff and flash flooding. We will need to watch this closely over the next few days and see which route has the greatest potential to occur. Last thing to note there is a good of snow on the ground well toour north. The next few airmasses that come down will not get totravel over that and this will keep those airmasses frommoderating much. Typically for us to get the real cold temps theairmass has got to move over some snow and ice across the centralCONUS and Plains otherwise it moderates far more than the modelsanticipate. Second this system later this week even if it doesn'tprovide us any winter weather it looks like it could provide rather significant winter impacts across northern LA and northern MS. This is more snow and ice on the ground aiding it additional cold air sliding south. This could be a re-enforcing setup for the next few weeks so I wouldn't anticipate any large and prolonged warmups for some time. /CAB/&&.AVIATION...(06Z TAFS)Issued at 1122 PM CST Sun Jan 5 2025A cold front with an associated line of showers and a fewthunderstorms continues to sweep east across the area tonight. Theline is currently passing over MSY, HUM, ASD, NEW, and isapproaching GPT. These terminals will continue to see MVFRvisibilities and ceilings over the next 1 to 2 hours with GPTclearing last around 08z. All of the terminals will see a periodof VFR conditions take hold between 08z and 12z as drier airbegins to surge into the region. However, at MCB, some lowerceilings will advect in from the northwest producing a period ofMVFR ceilings around 1500 to 2000 feet through the morning hours.These ceilings are expected to fully mix out with a return to VFRconditions after 16z. Breezy conditions are also expected behindthis front with sustained northwest winds of 15 to 20 knots inplace through the entire forecast period. &&.MARINE...Issued at 321 AM CST Mon Jan 6 2025A strong cold front will continue to quickly move through the waters this morning. Gusty northwest and northerly winds are developing behind the front prompting small craft advisory conditions through tonight. High pressure will build back over thewaters on Tuesday allowing for lighter winds and calmer seas through Wednesday night. However, a Gulf low pressure system will bring small craft advisory conditions back to the waters as it passes through the area Thursday through Saturday. /CAB/&&.PRELIMINARY POINT TEMPS/POPS...MCB 40 25 43 24 / 0 0 0 0 BTR 45 27 49 28 / 0 0 0 0 ASD 47 26 49 27 / 0 0 0 0 MSY 46 31 48 33 / 0 0 0 0 GPT 46 29 49 28 / 0 0 0 0 PQL 50 26 52 26 / 0 0 0 0 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...Cold Weather Advisory until 9 AM CST this morning for LAZ034>037- 039-046>048-056>060-065>067-071-076>087. Cold Weather Advisory from midnight tonight to 9 AM CST Tuesday for LAZ034>037-039-046>048-056>060-064>071-076>090.GM...Small Craft Advisory until 6 AM CST Tuesday for GMZ530-532-534- 536-538-550-552-555-557-570-572-575-577.MS...Cold Weather Advisory until 9 AM CST this morning for MSZ068>071- 077-083>088. Cold Weather Advisory from midnight tonight to 9 AM CST Tuesday for MSZ068>071-077-083>088.GM...Small Craft Advisory until 6 AM CST Tuesday for GMZ532-534-536- 538-550-552-555-557-570-572-575-577.&&$$SHORT TERM...CABLONG TERM....CABAVIATION...PGMARINE...CAB
