FXUS64 KLIX 111722 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1122 AM CST Mon Dec 11 2023 ...New AVIATION... .SHORT TERM... (Today through Wednesday) Issued at 225 AM CST Mon Dec 11 2023 Pressure gradient continues to breakdown from west to east across the region this morning. Along with clear skies and calmer winds, temperatures have dropped well into the 30s north of I10/12 with some locations at or winding up just a tad below freezing. A rather cool day is in store, however, with high pressure building in over the lower MS River Valley, expect plenty of sunshine today, so overall pleasant. The high pressure begins to lift north and east later tonight and into the day on Tuesday. Still with calmer winds and clear skies temperatures will likely drop into the 30s across the northern tier again by Tuesday morning...as always the cooler locations look to be in the typical drainage areas around the Pascagoula and Pearl River Basins. That said, guidance does have the surface high pressure moving north and eastward away, which may help allow pressure gradient to tighten once again, especially for the southern tier or closer to the immediate coast. These areas may see overnight lows held up just a bit, especially when compared to Monday morning. A strong easterly fetch will begin to develop by late Tuesday, which will help increase boundary layer moisture at least slightly despite the somewhat unfavorable fetch. The previous frontal boundary that recently moved through our region in the last day or two will get stuck over the southern Gulf under the strong surface high pressure. This will again help increase surface winds just a bit by Wednesday. That said, the forecast area should continue to remain dry as the remnant/passive front to our south will be just out of reach for any type of isentropic upglide that would be needed for the development of showers. (Frye) && .LONG TERM... (Wednesday night through Sunday) Issued at 225 AM CST Mon Dec 11 2023 The long term begins dry for the most part, but a tad on the breezy side as pressure gradient between a strong 1040mb+ high pressure system near the Great Lakes and lower pressures over the Gulf tighten across the local area. The easterly fetch will bring in some low level moisture, however, any moist return will be slow to occur given the direction of the fetch. A passive surface front will reside to our south over the southern Gulf Wednesday night into Thursday. Globals show some light QPF signal across the far Gulf waters, however, the region appears to remain dry at least going into the start of late week with little in the way of lift. Temperatures by this time will have started to rebound again with a slight increase in heights and thicknesses across the CWFA. That said, this appears to be rather modest again without much of a return flow to speak of help really bring in the warmer and moist conditions south of the aforementioned front. From here things get more...we'll say interesting. Globals generally start to diverge significantly (so from Thursday beyond the overall forecast confidence is VERY LOW). The synoptic pattern starts off in decent agreement we'll say, but the evolution of the pattern leaves much to be questioned. First, the GFS has an inverted surface trough sharpen over the Gulf. This feature begins to lift northward on Thursday and eventually closes off a surface low late Thursday and into Friday. The ECM shows a weak surface trough at the same time, but appears to be lagging slightly. Eyes then focus up stream over the Texas high plains as surface cyclogenesis takes shape and continues to move south and eastward toward the northwest Gulf by this weekend. Both GFS and ECM depict this feature "somewhat" well. However, the ECM doesn't really develop an initial low in the Gulf instead holds on to a surface trough or the old frontal boundary through this timeframe. The GFS takes the initial low and pushes it eastward over the Florida Peninsula and tends to be a bit more on the progressive side with the pattern. As the system over Texas moves into the Gulf, the GFS indicates that the parent trough will help push the earlier low downstream generally north and east along the east coast helping strengthen this system over the Gulf Stream as it lifts quickly north and east away from our CWFA. However, the ECMWF doesn't agree. In fact, the ECM actually further develops the surface feature over the northern and central Gulf and beyond holds the low over the gulf through the end of the period. The concern here is of course with a slower moving system more opportunity for rainfall...which of course is shown in the ECM. However, the GFS is quite a bit drier with most of the precipitation remaining offshore and the fact that the solution there is a bit faster. The CMC tends to take a more middle of the two route adding very little in terms of helping add long range confidence. EPS and GEFS respectively show a deepening surface low move across florida, but once again the respective ensemble means follow the parental deterministic guidance fairly closely. So, all that said, the bottom line again is low confidence. We do have POPs respectively for the best overlap and since the region should remain mostly in the cool sector think thunder probs will be a bit lower, unless the front across the Gulf finds its ways closer to our area prior to the eventual evolution of the system(s). Otherwise, regardless of the solution, breezy to windy conditions will be possible along with perhaps coastal flooding concerns, especially if the ECMWF materializes over the GFS. However, at this juncture it would be tough to even speculate specifics with such variations in the solutions in both globals and their ensembles. (Frye) && .AVIATION... (18Z TAFS) Issued at 1121 AM CST Mon Dec 11 2023 A broad surface high centered over the Lower Mississippi Valley will keep skies clear and VFR conditions in place at all of the terminals through tomorrow afternoon. Winds will be light from the north and northeast through the period. PG && .AVIATION... (06Z TAFS) Issued at 1118 PM CST Sun Dec 10 2023 As high pressure settles into the area, very light to calm winds are expected to prevail through the period with no significant cloud cover. The only real exception is KNEW where winds will be a little stronger (but still generally 10 kts or less) due to proximity to the lake. (DM) && .MARINE... Issued at 225 AM CST Mon Dec 11 2023 Winds and seas will continue to decrease through the morning and into the afternoon hours as pressure gradient begins to relax across the local waters. Moderate winds and seas can be anticipated early this week, however, the break from hazardous marine conditions will be short-lived as easterly flow strengthens over the local waters by midweek. From this point on, a potentially prolonged period of hazardous to even dangerous marine conditions is forecast from midweek through the next weekend. Small Craft Advisories are expected and gale products are becoming increasingly likely, especially over the open waters late week and into this weekend as the easterly flow around a strong high pressure centered to our northeast remains strong. (Frye) && .PRELIMINARY POINT TEMPS/POPS... MCB 57 33 60 36 / 0 0 0 0 BTR 61 37 64 40 / 0 0 0 0 ASD 59 36 62 39 / 0 0 0 0 MSY 57 45 60 47 / 0 0 0 0 GPT 58 38 60 41 / 0 0 0 0 PQL 59 34 63 38 / 0 0 0 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RDF LONG TERM....RDF AVIATION...PG MARINE...RDF