Please read the newsposts on the homepage! Some are rules some are archives from past events.
127 FXUS64 KLIX 042141AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA341 PM CST Sat Jan 4 2025...NEW SHORT TERM, LONG TERM, MARINE....SHORT TERM...(This evening through Sunday night)Issued at 341 PM CST Sat Jan 4 2025Winds have shifted to a more easterly or southeasterly directionacross the CWA this afternoon. This will be the start of a reboundin terms of temps and moisture ahead of the highly advertised coldfront due into the region by the end of the short term period.That said, before it moves through we have much to discuss. First, with a weak surface trough/front to our south, some verylight showers have developed courtesy of some weak isentropicupglide. Showers will remain possible through the night and into Sunday in advance of then a northward moving warm frontal boundary. The forecast area should emerge in the warm sector of the system developing first over the High Plains and then translating nearly due east along I40 from late tonight through Sunday afternoon. Strong upper troughing will continue to amplifyover the lower MS River Valley as the surface low moves east and upper low follows this same track close to I40 just lagging a bit.So, putting the story together here, surface flow increases tomore moderate levels on Sunday helping continue moistening theboundary layer. Aloft, height falls along with some modest jetdynamics could help generate some shower activity within the warmsector. SRH values at the time will be increasing as well as astrong 50kt or so LLJ begins to crank up. With the surface lowdeepening, and thanks to isallobaric processes, surface winds initially will back at least until the front moves close to the region later in the evening again enhancing SRH values. With somebroad scale lift, cannot rule out showers developing ahead of thefront and with ample wind shear cannot rule out some spinny showers, if you will. CAPE values will be a struggle with the bestinstability residing west of I55 and north of I10 where the bestlow level moisture pooling takes place. This too is where the best of the aforementioned lift will be...so the overall best severe weather potential will likely be over our northwest tier ofthe CWFA. The highest potential comes in by early evening at current best estimated timing (cold pool dynamics can rush these things along). As it enters the CWFA instability tanks due to loss of daytime heating after sunset, which should overall limit the threat downstream. However, forcing will be just enough to allow a squall line to pass through much of the forecast area overall weakening as it moves east with the best forcing moving out and little if any instability left closer to the Alabama border. Still, if the line can maintain and given the 0-3km line-normal bulk shear vectors, think a mesovort or two will be possible IF bowing segments can align southwest to northeast in terms of motion. Overall impacts will be damaging wind gusts, but we cannot forget the intense wind shear associated with this very dynamic heavy system...so a tornado or two will be possible. The question is will the wind shear be too much and limit the overall threat by rolling the updrafts? Given a low cape high shear event this is common and overall could also limit the overall potential especially across the eastern tier at least from a tornadic standpoint. Damaging straightline winds, however, will still be aconcern regardless. (Frye)&&.LONG TERM...(Monday through Friday night)Issued at 341 PM CST Sat Jan 4 2025By Monday the front is through the region and strong CAA is takingplace. Temperatures will remain steady from upper 30s near MCB tothe middle 40s across the southshore. Strong northerly flow willeventually break down late Monday and into Tuesday as highpressure tries to build in from the north. Temperatures willremain much below average (struggling to make mid and upper 40s)Tuesday and Wednesday. Overnight lows are forecast to drop intothe middle 20 across the northern tier overnight Mon, Tues, andWed. With at least some wind, Cold Weather Advisories will likelybe needed and perhaps Freeze products for the south shore if aCold Weather product isn't actually needed. Regardless, animpactful freeze is expected for most locations outside of mid/lowerPlaquemines early next week. By midweek, eyes turn west as an H5 trough begins to amplify overthe Desert Southwest. At the same time, a surface coastal troughtries to develop near the mouth of the Rio Grande Valley. Theglobals have come into better agreement, at least the ECM and GFSin terms of timing and surface low placement as the trough swingseastward and the developing Gulf low moves north and east towardour general vicinity. The models have nudged the surface cyclonenorthward a bit, which would alleviate any concerns for wintryprecip, if the latest deterministic runs come into fruition. Thereis still plenty of time to watch just in case, but for now a coldrain looks to be a good bet. As the surface feature spreads northand eastward, another cold front will slide through, which againshould keep our temperatures below average to round out the longterm period. (Frye)&&.AVIATION...(18Z TAFS)Issued at 1128 AM CST Sat Jan 4 2025VFR conditions early in the cycle will gave way to increasing lowlevel cloudiness leading to eventual MVFR or lower conditions bythe end of the period. Winds will gradually continue to shift to amore southeasterly direction with time and wind speed will beginto increase early in the day on Sunday. A few showers will bepossible for most terminals, but this should bebrief/isolated...so used PROBs to cover this potential. (Frye) &&.MARINE...Issued at 341 PM CST Sat Jan 4 2025Cautionary headline conditions will evolve to Small Craft Advisoryconditions ahead of an approaching cold front due into the regionlate Sunday or very early Monday morning. As southerly windsbuild, seas will respond and build to hazardous thresholds. As the front nears or immediately behind the front, a couple of gale force gusts aren't out of the question, however, at this juncture this looks a bit too infrequent for a Gale Watch for now. A Gale Watch or Warning may be required in subsequent updates if windspeed forecasts increase slightly. Behind the front, winds and seas remain hazardous through Monday night with gradual improvement by late Tuesday through midweek or so. Although improving, pressure gradient will still be just enough to keep winds and seas moderate, which may require the need for additionalCautionary Headlines from midweek onward. (Frye) &&.PRELIMINARY POINT TEMPS/POPS...MCB 49 73 30 40 / 20 80 100 0 BTR 56 79 34 45 / 20 70 100 0 ASD 54 74 36 48 / 50 60 100 0 MSY 58 76 37 47 / 50 40 100 0 GPT 53 70 36 49 / 30 50 100 0 PQL 51 75 39 55 / 20 40 100 0 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...None.GM...Small Craft Advisory from 6 PM this evening to 6 AM CST Monday for GMZ530-532-534-536-538-555-557-575-577. Small Craft Advisory until 6 AM CST Monday for GMZ550-552-570- 572.MS...None.GM...Small Craft Advisory from 6 PM this evening to 6 AM CST Monday for GMZ532-534-536-538-555-557-575-577. Small Craft Advisory until 6 AM CST Monday for GMZ552-570-572.&&$$SHORT TERM...RDFLONG TERM....RDFAVIATION...RDFMARINE...RDF
