553 FXUS64 KLIX 181306 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 806 AM CDT Mon Sep 18 2017 ...SOUNDING DISCUSSION... Winds are light and rather variable through 500 mb then westerly aloft. Instability is a bit lower today. There is dry air above 700 mb and an elevated inversion at 600 mb. Scattered showers and storms will develop this afternoon though coverage should be a little less than this weekend. Krautmann && .PREV DISCUSSION... /issued 328 AM CDT Mon Sep 18 2017/ SHORT TERM... A deep layer ridge axis centered directly over the Gulf South will be the dominant weather feature driving the weather forecast through Wednesday. As a result, very similar conditions as seen the last few days will persist through the middle of the week. Expect to see slightly above normal temperatures and daytime highs climb into the upper 80s and lower 90s, and overnight lows dip into the lower to middle 70s. With weak boundary layer flow and ample low level moisture in place, the prospect of fog forming over inland areas away from the coastal waters will be fairly high each night. Any fog should quickly mix out by mid- morning as drier air in the mid to upper levels begins to mix down to the surface. A seabreeze cycle will be the driver of most convective activity each day. Expect to see most shower and thunderstorm activity hold off until the mid to late afternoon hours when peak heating is achieved. Have kept in a chance POP of 30 to 40 percent each day as these scattered seabreeze and lakebreeze induced showers and thunderstorms develop. The convection will be very diurnal, and expect to see most shower and thunderstorm activity dissipate by the late evening hours. LONG TERM... Heading into the latter part of the week and the weekend, the pattern will shift as the ridge axis breaks down and a broad and fairly weak trough axis forms across the Gulf South and into the Gulf of Mexico. This broad and ill defined trough axis will not only bring a small increase in upper level forcing to the region, but a surge of deeper tropical moisture should also feed in from the south and east by Thursday and Friday and linger over the area through the weekend. With less convective inhibition and more moisture to work with, have higher POP values of 40 to 50 percent in the forecast each afternoon. There will not be any large scale synoptic feature to latch onto for convective initiation, so most convection will continue to form along mesoscale boundaries like the seabreeze front and outflows from previous convection. The lack of wind shear or a decent cold pool aloft also looks to limit the strength of any thunderstorms. At worst, a few of the stronger cells could produce locally heavy downpours and frequent lightning strikes both Thursday and Friday. The convection should also be highly diurnal, and still expect to see low rain chances during the more stable overnight hours. Temperatures will be near normal through the weekend with highs in the upper 80s and lows in the upper 60s and lower 70s. AVIATION... Ceilings and vis restrictions will cause most terminals to fall into IFR conditions this morning and again tonight. Decks and vis will rapidly improve after sunrise. Low chance sh/ts activity will keep this taf set mention free but updates will take care of any sites that are expected to be affected. MARINE... High pressure will remain across the eastern half of the gulf keeping winds weak and southerly. These conditions are expected to be maintained through the week. DECISION SUPPORT... DSS code: Green. Deployed: None. Activation: None. Activities: None. Decision Support Services (DSS) Code Legend Green = No weather impacts that require action. Blue = Long-fused watch, warning, or advisory in effect or high visibility event. Yellow = Heightened impacts with short-fused watch, warning or advisory issuances; radar support. Orange = High Impacts; Slight to Moderate risk severe; nearby tropical events; HazMat or other large episodes. Red = Full engagement for Moderate risk of severe and/or direct tropical threats; Events of National Significance. && .PRELIMINARY POINT TEMPS/POPS... MCB 91 71 90 70 / 30 30 40 20 BTR 93 72 92 72 / 30 30 40 20 ASD 91 71 91 72 / 30 30 40 10 MSY 91 74 90 74 / 30 30 40 10 GPT 89 73 89 73 / 20 20 40 10 PQL 90 71 90 70 / 20 20 40 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$