Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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360 FXUS64 KLIX 172333 AAA AFDLIX Area Forecast Discussion...UPDATED National Weather Service New Orleans LA 633 PM CDT Mon Jun 17 2024 ...NEW AVIATION... .SHORT TERM... (This evening through Wednesday night) Issued at 244 PM CDT Mon Jun 17 2024 NHC has started advisories on Potential Tropical Cyclone (PTC) One in 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 forecasts are 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 waters will cause tides to rise above normal by tomorrow morning and minor coastal flooding is likely during high tide. Water levels will be highest during high tide on Wednesday, and could result in a some low lying roads becoming impassable, mainly in the more vulnerable areas on the west/southwest side of Bay St. Louis. Based on the forecast, water could also cover some low lying portions of Hwy 1 between Port Fourchon and Grand Isle. Looking at the probabilistic water level guidance, there is still some potential that a coastal flood warning may be needed Wednesday morning, mainly for areas from Shell Beach to Bay St. Louis. Regarding water levels in the lake, will again hold off on any headlines around the lake shores for now as water levels in the lake are expected to lag those on the open coast by 1-2 days. The guidance at New Canal on the south shore does indicate an advisory may 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 will still be plenty of moisture to support scattered to numerous showers and storms across the area, but rainfall rates should come down just a bit and the duration of heavier rain in any location should also limit the flood threat. Thus WPC continues to carry only a marginal risk of excessive rainfall leading to flash flooding on Tuesday. By Wednesday the bulk of the moisture shifts even further southwest with drier air moving into the local area. Generally scattered showers and storms are still in the forecast, with possibly higher coverage across coastal southeast Louisiana. With the precipitable water dropping back down closer to 1.75, which is above normal but not remarkably so, rainfall rates are not expected to be as dramatic as what we`ve seen today, and the flooding 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 rain chances. Morning lows will be above normal owing to the higher than normal dewpoints preventing the temps from dropping much below the mid 70s most places. && .LONG TERM... (Thursday through Sunday night) Issued at 244 PM CDT Mon Jun 17 2024 Going into Thursday and the weekend the forecast is a little murky and kind of depends on where various moisture plumes end up. Currently, the NBM/consensus approach keeps the deeper tropical moisture out of our local forecast area, though there is quite a bit of uncertainty regarding the evolution of various vorticity features rotating through the central American gyre. With no confidence in any specific ensemble member solutions, see no reason to stray from the NBM at this point in the longer term forecast. This results in scattered to numerous POPs each day mainly across southern areas with lower POPs farther inland. Temperatures should be near to above normal based on the current forecast. && .AVIATION... (00Z TAFS) Issued at 629 PM CDT Mon Jun 17 2024 Convection will become more isolated through the evening and overnight. Cannot rule out a rogue shower or two, but this should be the exception rather than the rule. Convection looks to again be possible on Tuesday with the best potential over the south/western terminals such as BTR and HUM. Could see brief MVFR CIG/VIS in the heaviest convection. Southeasterly winds will increase and become gusty with some of the southern terminals approaching gusts in excess of 30 kts. (Frye) && .MARINE... Issued at 244 PM CDT Mon Jun 17 2024 No significant change to the marine forecast with this package. Generally still expecting advisory conditions across most of the coastal waters through midweek as winds respond to a tightening pressure gradient between low pressure in the Bay of Campeche and high pressure centered over the east coast. Latest forecast does have a period of potentially gale conditions, mainly in the form of gusts from Tuesday night through Wednesday, but confidence is low enough that we will hold off on any gale watch for the time being. Regardless of whether winds reach gale conditions, a long fetch combined with a swell train emanating from the low in the SW Gulf will likely push seas to at least 9 to 12 feet over the open waters by Tuesday night into Wednesday. Hazardous to dangerous conditions will persist through much of the work week, especially over the open waters, and are not likely to see any significant improvement until Thursday night or Friday. As noted above, with the prolonged southeasterly winds, east and south facing shorelines will see increased water levels beginning overnight tonight, and a Coastal Flood Advisory will remain in effect 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 lakes for 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...DM LONG TERM....DM AVIATION...RDF MARINE...DM