Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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249 FXUS64 KLIX 211142 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 642 AM CDT Fri Jun 21 2024 ...New AVIATION... .SHORT TERM... (Today through Saturday) Issued at 315 AM CDT Fri Jun 21 2024 While the low level circulation of former Tropical Storm Alberto dissipated yesterday afternoon, the mid and upper circulation can still be seen on water vapor exiting the west coast of Mexico early this morning. The Central American Gyre looks to aid the development of another low and mid level circulation over the Bay of Campeche today. The upper ridge that had been over the Mid Atlantic States is reforming to the west-southwest, centered near Evansville, Indiana early this morning. Invest 92L was noted off the Florida East Coast to the east of Jacksonville. The pressure gradient between high pressure to the north and low pressure near the Bay of Campeche is not as strong this morning has it has been for much of the week, meaning winds are quite a bit lighter this morning. To this point of the morning, northeasterly winds haven`t been particularly effective in pulling drier air into the area quite yet. Temperatures at 3 AM CDT ranged from the mid 70s to lower 80s across the area. Dew points ranged from the upper 60s over southwest Mississippi to the mid 70s near and south of Interstate 10. There was a patch of mid level cloud cover near the Alabama-Mississippi border moving westward that could briefly produce cloudy skies this morning. Radar was picking up a few very small rainshowers this morning, but areal coverage is so small at this point that very few, if any, people will experience them. It was rather tough to find any stations reporting measurable rainfall yesterday, and it will be even tougher today. The upper ridge will continue to sink south and southwest today and Saturday, with the axis from eastern New Mexico to the Florida Panhandle by Saturday evening. This will continue to gradually dry out the column over the next 36 hours. Precipitable water values near 1.6 inches last night should dry out to 1.1 inches across the north to about 1.5 across the south by Saturday afternoon. While we can`t totally rule out a few showers or thunderstorms today, a 20 to 25 percent chance of measurable precipitation west of Interstate 55 this afternoon is probably overstating things. Any convection on Saturday is likely to remain offshore, and possibly not even there. As the atmosphere dries out over the next couple of days, cloud cover will be more limited, and we should heat up a couple of degrees from yesterday in most areas, and a couple degrees more on Saturday. With slightly lower dew points expected, that should keep heat index values between 100 and 107F, just below advisory criteria of 108F. && .LONG TERM... (Saturday night through Thursday) Issued at 315 AM CDT Fri Jun 21 2024 The upper ridge will continue to work its way westward Sunday through midweek, and be centered near the Arizona-New Mexico border by Tuesday/Wednesday. As troughing develops near the Atlantic Coast, that will up the local area in northwesterly mid level flow by midweek. The eastward extension of the ridge axis may keep any thunderstorm development isolated Monday afternoon, but as we get into Tuesday and beyond, moisture levels are likely to become sufficient enough for scattered thunderstorm development. If there is going to be any concern for severe weather or heavy rainfall, it wouldn`t occur much before Wednesday or Thursday. The larger concern for Sunday into at least the early portion of the week will be the potential for heat related issues. With highs well into the 90s, and moisture returning, heat index values look to top out in the 105 to 110F range on Sunday in some areas, and perhaps a few notches higher on Monday over a larger area. That may necessitate Heat Advisories over portions of the area in later forecasts. Beyond Monday, afternoon thunderstorms should have high temperatures top out a few degrees lower than Sunday/Monday. Didn`t depart very far from NBM deterministic highs, but did bump up overnight lows a notch. && .AVIATION... (12Z TAFS) Issued at 633 AM CDT Fri Jun 21 2024 All terminals VFR at issuance time. There is an area of mid level clouds near FL080 between KMOB and KGPT moving westward and will likely move across most or all terminals this morning/early afternoon if they don`t mix out. That layer of moisture appears to be relatively thin. There is also a very minor threat of SHRA/TSRA at terminals generally west of Interstate 55, but expected areal coverage is not large enough to justify a mention in the terminal forecast at this time. Overnight tonight, VFR conditions are expected. && .MARINE... Issued at 315 AM CDT Fri Jun 21 2024 Wind speeds have relaxed below 20 knots across the open waters and even lower over the protected waters. Have cancelled the Small Craft Advisory over any remaining waters and replaced it with Small Craft Exercise Caution headlines over primarily the western open waters. Will leave the Coastal Flood Advisory in place through the high tide cycle this afternoon, and let day shift take a look at conditions this morning to see how extensive an area may need one for Saturday`s high tide cycle, or whether it can be eliminated entirely this afternoon. Once winds drop off this afternoon, the only real concern for mariners will be the potential for thunderstorms, and that should be rather limited until perhaps Tuesday or Wednesday. && .PRELIMINARY POINT TEMPS/POPS... MCB 92 70 95 73 / 10 0 0 0 BTR 95 74 98 76 / 20 10 10 0 ASD 93 71 95 76 / 10 0 10 0 MSY 92 77 94 78 / 20 0 10 0 GPT 91 73 93 76 / 10 0 10 0 PQL 96 71 97 75 / 0 0 0 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...Coastal Flood Advisory until 6 PM CDT this evening for LAZ058- 060-066>070-076>078-080-082-084-086-087. GM...None. MS...Coastal Flood Advisory until 6 PM CDT this evening for MSZ086>088. GM...None. && $$ SHORT TERM...RW LONG TERM....RW AVIATION...RW MARINE...RW