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331 FXUS64 KLIX 172058AFDLIXArea Forecast DiscussionNational Weather Service New Orleans LA358 PM CDT Mon Jun 17 2024...New SHORT TERM, LONG TERM, AVIATION, MARINE....Key Messages...1. Scattered to numerous showers and thunderstorms are expected again Tuesday, but the heavy rain threat as a whole will be lower as the overall coverage and duration of heavier rain decreases.2. Strong east-southeasterly winds across the northern Gulf will cause tide levels to rise above normal tonight, with minor coastalflooding expected Tuesday during the time of high tide and minor to potentially moderate coastal flooding during high tide Wednesday. A few low lying roads may become covered with water or impassable, especially during high tide Wednesday morning.3. Winds will become quite gusty Tuesday and Wednesday and could blow around some light weight outdoor items. A wind advisory may be needed for some portions of the area, mainly south of the tidallakes.&&.SHORT TERM...(This evening through Wednesday night) Issued at 244 PM CDT Mon Jun 17 2024NHC has started advisories on Potential Tropical Cyclone (PTC) Onein the Bay of Campeche. This system is not expected to have any direct impacts on the local area, but due to its large size and interaction with a strong high over the eastern US, some indirect impacts are likely. PTC One is forecast to become gradually better organized through the short term. As this happens, the pressure gradient will tighten across the local area, resulting in a strengthening wind field across the local area. Currently the wind and gust forecastsare still just below wind advisory criteria, but the next shift or two will need to continue taking a closer look. IF a wind advisory becomes necessary, it is most likely for areas south of the tidal lakes in southeast Louisiana.Strong east-southeasterly flow across the northern Gulf waterswill cause tides to rise above normal by tomorrow morning andminor coastal flooding is likely during high tide. Water levelswill be highest during high tide on Wednesday, and could result ina some low lying roads becoming impassable, mainly in the morevulnerable areas on the west/southwest side of Bay St. Louis.Based on the forecast, water could also cover some low lyingportions of Hwy 1 between Port Fourchon and Grand Isle. Looking atthe probabilistic water level guidance, there is still somepotential that a coastal flood warning may be needed Wednesdaymorning, mainly for areas from Shell Beach to Bay St. Louis.Regarding water levels in the lake, will again hold off on anyheadlines around the lake shores for now as water levels in thelake are expected to lag those on the open coast by 1-2 days. Theguidance at New Canal on the south shore does indicate an advisorymay be needed by the high tide cycles late Wednesday and Thursday,though.The plume of deep tropical moisture that has been with us since yesterday will shift a bit to the west tomorrow. While there willstill be plenty of moisture to support scattered to numerousshowers and storms across the area, but rainfall rates should comedown just a bit and the duration of heavier rain in any locationshould also limit the flood threat. Thus WPC continues to carryonly a marginal risk of excessive rainfall leading to flashflooding on Tuesday. By Wednesday the bulk of the moisture shifts even furthersouthwest with drier air moving into the local area. Generallyscattered showers and storms are still in the forecast, withpossibly higher coverage across coastal southeast Louisiana. Withthe precipitable water dropping back down closer to 1.75, which is above normal but not remarkably so, rainfall rates are notexpected to be as dramatic as what we've seen today, and theflooding rain threat is fairly low. Afternoon temperatures will generally be near to below normal through the short term due to cloud cover and the higher rainchances. Morning lows will be above normal owing to the higherthan normal dewpoints preventing the temps from dropping muchbelow the mid 70s most places.&&.LONG TERM...(Thursday through Sunday night) Issued at 244 PM CDT Mon Jun 17 2024Going into Thursday and the weekend the forecast is a little murkyand kind of depends on where various moisture plumes end up.Currently, the NBM/consensus approach keeps the deeper tropicalmoisture out of our local forecast area, though there is quite abit of uncertainty regarding the evolution of various vorticityfeatures rotating through the central american gyre. With no confidence in any specific ensemble member solutions, seeno reason to stray from the NBM at this point in the longer termforecast. This results in scattered to numerous POPs each day mainlyacross southern areas with lower POPs farther inland. Temperatures should be near to above normal based on the currentforecast.&&.AVIATION...(18Z TAFS)Issued at 244 PM CDT Mon Jun 17 2024Outside of showers and storms, expect prevailing VFR to MVFR conditions. Scattered to numerous showers and storms will bringoccasional restrictions to the terminals today as deep tropicalmoisture moves through the area. High rainfall rates will temporarily reduce visibility to ifr conditions as showers and/orthunderstorms move over the terminals. Convection should wane somewhat after sunset, but will increase in coverage again by mid to late morning Tuesday. Winds will also strengthen Tuesday in response to a tightening pressure gradient.&&.AVIATION...(12Z TAFS)Issued at 634 AM CDT Mon Jun 17 2024Most terminals VFR at issuance time this morning, with theexception of KMCB, where IFR ceilings were in place. Convectionwas rather isolated at 11z, but expect areal coverage to blossomin the next few hours as surface heating kicks in. MVFR ceilingsmay become predominant by 15z. SHRA will be main weather for thenext few hours with the threat of TSRA at pretty much allterminals by midday. Areal coverage should be sufficient for TEMPOduring the afternoon at all terminals with IFR or lowervisibilities and MVFR ceilings. While wind gusts in excess of 30knots are possible with the strongest cells, not high enoughconfidence to carry in most terminals. Areal coverage willdiminish toward 00z Tuesday, with little or no precipitationbetween about 02z and 10z. MVFR to IFR ceilings may return towardsunrise Tuesday. Sustained winds near 15 knots possible during much of the daytimehours today before diminishing this evening. With low pressureexpected to develop over or near the Bay of Campeche later todayor tomorrow, stronger sustained winds are anticipated during thedaytime hours tomorrow, with gusts of 25 to 30 knots not out ofthe question by mid-morning.&&.MARINE...Issued at 244 PM CDT Mon Jun 17 2024No significant change to the marine forecast with this package.Generally still expecting advisory conditions across most of thecoastal waters through midweek as winds respond to a tighteningpressure gradient between low pressure in the Bay of Campeche andhigh pressure centered over the east coast. Latest forecast doeshave a period of potentially gale conditions, mainly in the formof gusts from Tuesday night through Wednesday, but confidence islow enough that we will hold off on any gale watch for the timebeing. Regardless of whether winds reach gale conditions, a longfetch combined with a swell train emanating from the low in the SWGulf will likely push seas to at least 9 to 12 feet over the openwaters by Tuesday night into Wednesday. Hazardous to dangerous conditions will persist through much of the work week, especiallyover the open waters, and are not likely to see any significantimprovement until Thursday night or Friday.As noted above, with the prolonged southeasterly winds, east andsouth facing shorelines will see increased water levels beginningovernight tonight, and a Coastal Flood Advisory will remain ineffect and will likely eventually need extended into Thursday. Coastal Flood Warnings may be necessary for more sensitive spots by Tuesday night or Wednesday. Will again hold off on tidal lakesfor now, as it appears their main water concerns may hold off until Wednesday night or Thursday.&&.PRELIMINARY POINT TEMPS/POPS...MCB 72 85 71 90 / 30 40 0 30 BTR 76 88 76 92 / 40 60 10 50 ASD 75 87 76 90 / 60 60 10 50 MSY 79 88 81 90 / 50 70 10 60 GPT 77 87 76 90 / 30 50 20 40 PQL 75 91 75 92 / 30 40 20 30 &&.LIX WATCHES/WARNINGS/ADVISORIES...LA...Small Craft Advisory until 7 AM CDT Thursday for LAZ068. Coastal Flood Advisory from 1 AM Tuesday to 4 PM CDT Wednesday for LAZ066>070-076-078.GM...Small Craft Advisory from 7 AM Tuesday to 7 AM CDT Thursday for GMZ530-532-534. Small Craft Advisory until 7 AM CDT Thursday for GMZ536-538-550- 552-555-557-570-572-575-577.MS...Coastal Flood Advisory from 1 AM Tuesday to 4 PM CDT Wednesday for MSZ086>088.GM...Small Craft Advisory from 7 AM Tuesday to 7 AM CDT Thursday for GMZ532-534. Small Craft Advisory until 7 AM CDT Thursday for GMZ538-550-552- 555-557-570-572-575-577.&&$$SHORT TERM...DMLONG TERM....DMAVIATION...DMMARINE...DM
