271 FXUS64 KLIX 102348 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 648 PM CDT Tue Oct 10 2023 ...New AVIATION... .SHORT TERM... (This evening through Friday night) Issued at 442 PM CDT Tue Oct 10 2023 High clouds streaming in all day lead to a mostly cloudy day. Temperatures struggled to get into the 80s for much of the area. Main focus of the forecast is in the next 48 hours and really hours 12 to 36. Tonight will be quiet but shortly after sunrise tomorrow things should quickly start to deteriorate across the coastal waters and rain will begin to move in from the Gulf but how much rain is a big question mark. Around midday winds will likely begin to increase quickly over land areas especially along the coast. Tides will then respond during the afternoon and remain high through the night. This will be all from a sfc low that will traverse the north-central Gulf tomorrow and into the northeastern Gulf by Thursday morning. The remnants of Max has helped to get things going with the sfc low still currently in the southwestern Gulf but it will be the energy from Lidia that finally starts to kick this low off to the northeast early tomorrow morning. The sfc low will continue to deepen thanks to its locations with the subtropical jet which will provide optimal divergence aloft. The sfc low will follow a weak warm front that will move towards the northeast Gulf tomorrow night and this track will keep it offshore just off our coast. With that we will see no instability and remain in the so called cool sector. That will mean any rain we see will be shower and not anticipating any thunder over the land areas. That said very deep moisture will be pushing into the area and it still looks like the southeast half of the CWA will see Pws of 2-2.25". This is well above the 90th percentile but the problem could be how much convection occurs across the Gulf. It is highly anticipated that a lot convection will occur in our coastal waters and into the Gulf and this will likely cut off a good portion of the area from the deeper moisture. Impacts: Tides - Luckily we will not have a prolonged period of onshore flow that will cause the water to build and pile up along the coast. This will be a rather quick hitter and strong onshore flow likely will only occur for about 18 to maybe 24 hours and even then these winds will be backing during those final 12 hours becoming easterly by 12z and then ENE by 18z. Winds will then continue to back around to the northeast during the late afternoon and through the evening along with increasing significantly from 18z till 00z. Other positive aspect helping to keep tides from getting worse is we are once again moving towards neap tide which is Thursday and Friday. Tidal ranges are by far the smallest during this time and that is working to help keep the peak from this event worse. Given the strength of the winds and perfect direction down Lake Borgne locations in St Bernard near Shell Beach and along the east facing shores of St Bernard and Plaquemines will likely see the greatest impact from tides where tidal inundation of 1.5 to 3' is expected. The other area of greatest concern will be locations outside of the levees around the south shore of Lake Pontchartrain. Again the winds will have an almost optimum trajectory to push water into the Lake and then to the southwest. In these areas 1-2.5' of inundation will be possible. On the north side of the Lake there may initially be some coastal flooding but once the stronger northeast winds get going late afternoon/early evening these locations should quickly improve. Only other spot with warnings is the Rigolets and Hancock county. Waveland always tends to overachieve and should still see 1.5-2' of inundation which is right at the point of adv/warning. Tides will slowly back off through the morning hours Thursday as winds quickly subside. Coastal Flood warning for much of the tidal lakes, Hancock county, and east facing shores of Plaquemines and St Bernard. Coastal flood advisory on the north-central and northwest side of Lake Pontchartrain. Winds - a pressure gradient of 4 to 5 mb across just the southeastern half of the CWA is already leading to extremely hazardous winds and seas across the coastal waters but this will also lead to a rather windy day and evening across much of the area. Luckily the strongest winds will be out of the northeast so for much of the area winds will be coming from and over the land but easterly to ene winds around midday and early afternoon will still cause windy conditions across coastal MS. During the afternoon and evening hours as the pressure gradient tightens and winds continue to back to the northeast very strong winds will then come across southeast LA and these winds will come off the Lake and the Gulf. With that locations around the New Orleans metro and across St Bernard and Plaquemines will see sustained winds of 20 to 30 mph at times with gusts likely approaching 45 mph at times. Shell Beach and Lakefront both wouldn't be a surprise if they touched 50 mph. Biggest concern though is that the strongest winds could occur around evening rush hour. It looks like the worst may be between 23z and 3z so it would catch the back end of rush hour traffic and with all of the elevated roads and high bridges in the area crosswinds will be hazardous for high profile vehicles. Coastal MS and southeast of a line from LaPlace to Houma has a wind advisory out. Rain - This is the least likely of the concerns to cause any major impacts. WPC did remove the Slight Risk out of all of our area with the exception of the mouth of the River, which is basically water anyway. The track of the sfc low and the nature of the setup will keep the majority of the rain to the north and east of the center of the sfc low. This will allow some rain to move in across the CWA maybe as early as tomorrow morning but that will push off to the east and the heavier rain will remain confined to the coast and likely the Gulf. There is one small aspect that keeps popping up on many of the models and that is possible band of light to moderate rain that appears to be associated with a deformation axis. That said even if this did develop at the best we would see moderate rain with that feature and that will be welcomed if it happens. In all most people will probably be quite upset with the lack of rainfall they get. STill looking at widespread 0.5 to 2 inches over much of the area but there could be some areas that see even less rain while the immediate SELA coast could see near 3". The other aspect for rain not being as much a concern will be the sfc low quickly exiting the area. Our sfc low will quickly will be push off to the ENE and winds and rain will slack off considerably by sunrise if not early on Thursday. That said we may see more light rain return Thursday evening and into Friday as the remnants of Lidia try to move through. However we will likely be cleaned out for the most part and no real time to recover prior to it so not anticipating much outside of light rain and cloud cover. Friday should be quiet before the next cold front moves into the region this weekend. /CAB/ && .LONG TERM... (Saturday through Monday night) Issued at 442 PM CDT Tue Oct 10 2023 The long term forecast is still looking to be on track as an upper level trough slides across the central U.S. This transitions upper level flow to zonal through Friday and Saturday, before it switches again, to northwesterly, following the trough moving off to the east and a ridge building to the west. At the surface a cold front will sweep through our area late Friday and into Saturday, bringing a drier and cooler air mass with it. Some offshore showers will remain possible late Friday night into early Saturday morning as a frontal boundary hangs around the area. Beyond this, PoPs are at or near zero through the remainder of the forecast period. Following the cold front, it will be fairly windy late Saturday and throughout Sunday. Temperatures overnight Saturday will fall into the 50s and Sunday night some northern areas will even fall to the 40s. High temps will sit in the 70s each day through mid week starting Sunday. /HL/ && .AVIATION... (00Z TAFS) Issued at 626 PM CDT Tue Oct 10 2023 Currently VFR conditions, and that should remain the case for about the next 9-12 hours. Already seeing some radar echoes to the south and southwest at about FL100-FL150, which goes along with some of the surface obs we've seen out that way. Expect a gradual lowering of ceilings overnight, and perhaps some -RA/-SHRA by sunrise. MVFR flight restrictions should be necessary by mid morning, especially at the southern terminals of KHUM/KNEW/KMSY. At least some possibility of IFR ceilings during the afternoon hours. Expect at least some improvement during Wednesday evening as the main portion of the system pulls away to the northeast, but widespread improvement to VFR ceilings may not occur until mid- morning Thursday. Forecast soundings do not indicate that significant instability is available during this event, and TSRA has not been included in any of the terminal forecasts. Winds will also be an issue from mid morning Wednesday through the evening hours with wind gusts out of the northeast, potentially gusting to 25 to 35 knots, with the higher speeds primarily at KNEW and KMSY. This has the potential to pose some crosswind issues, possibly on both east- west and north-south oriented runway configurations. Winds should begin to diminish from west to east by mid to late evening Wednesday. && .MARINE... Issued at 442 PM CDT Tue Oct 10 2023 Quiet for now but conditions will quickly go down hill overnight and especially through the day tomorrow. A sfc low will traverse across the coastal waters while slightly deepening. This will ramp the winds up approaching 30-35kts sustained tomorrow afternoon and evening with gusts approaching 45-50kts. With that the gale Watch was upgraded to a warning earlier today but there is a small chance that Storm conditions could develop on the backside of the low as it moves towards the northeastern Gulf. Seas of 10 to as high as 14 ft can be expected with locally higher seas possible. As strong as the winds will be they should quickly back off during the early morning hours Thursday. Much lighter winds will be back in place Thursday afternoon through Friday but we could see winds pick back up as a cold front approaches Saturday. /CAB/ && .PRELIMINARY POINT TEMPS/POPS... MCB 60 70 56 81 / 30 60 30 20 BTR 63 71 59 83 / 40 70 20 20 ASD 62 73 58 79 / 20 90 50 30 MSY 68 74 64 78 / 30 90 50 20 GPT 65 74 59 79 / 20 90 60 30 PQL 62 76 58 79 / 20 90 60 30 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...Wind Advisory from 1 PM Wednesday to 6 AM CDT Thursday for LAZ058>060-064>070-076>078-087>090. Coastal Flood Warning from 7 PM Wednesday to 4 PM CDT Thursday for LAZ058-060-069-070-076>078-087. Coastal Flood Advisory from 7 PM Wednesday to 4 PM CDT Thursday for LAZ080-082-084. GM...Gale Warning from 10 AM Wednesday to 6 AM CDT Thursday for GMZ530-532-534-536-538-550-552-555-557-570-572-575-577. MS...Wind Advisory from 1 PM Wednesday to 6 AM CDT Thursday for MSZ086>088. Coastal Flood Warning from 7 PM Wednesday to 4 PM CDT Thursday for MSZ086. GM...Gale Warning from 10 AM Wednesday to 6 AM CDT Thursday for GMZ532-534-536-538-550-552-555-557-570-572-575-577. && $$ SHORT TERM...CAB LONG TERM....HL AVIATION...RW MARINE...CAB