Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
030 FXUS64 KLIX 010503 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1203 AM CDT Mon Sep 1 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .SHORT TERM... (Today through Tuesday) Issued at 1200 AM CDT Mon Sep 1 2025 Upper ridging over the Rockies tonight. Upper troughs from the Canadian Maritime Provinces to Virginia, and over the Canadian Prairie Provinces with weak ridging in between. This is producing northwesterly mid-level flow over the Lower Mississippi River Valley. Going by surface winds, the frontal boundary is offshore, and so is any lingering convection this evening. Drying was noticeable on the LIX evening sounding with the precipitable water value at 1.56 inches, which was comparable to the values at JAN and SHV. That`s just above the 25th percentile climatologically locally. It was also noticeable in the afternoon dew points north of Interstate 10, where dew points dropped into the 60s, even as low as 62 at McComb. The northwesterly upper flow will continue across the Lower Mississippi River Valley through the daytime hours Tuesday, and likely well beyond that point. The only real issue is timing of shortwaves moving through that upper flow, and whether there will be sufficient moisture and forcing to produce any more than isolated convection. Probably looking at no more than isolated coverage at any one time Monday during the day over lower portions of the Louisiana coastal parishes. For the 12 hours as a whole, we might justify 30 percent or so at Houma, but that might be overstating things. Forcing may be a little better on Tuesday across even northern portions of the area, but anything much more than 30 percent PoPs doesn`t look justified for most of the area, as precipitable water values remain around 1.5 inches. While high temperatures look to remain around 90 degrees both days, humidity levels are expected to be lower than what we would normally associate with Labor Day weekend. Maximum apparent temperatures in the lower and middle 90s will seem fairly comfortable. Overnight lows in the upper 60s and lower 70s are on tap for most of the area, with the possible exception of a few areas immediately downwind of Lake Pontchartrain that are likely to remain in the mid 70s. && .LONG TERM... (Tuesday night through Sunday) Issued at 1200 AM CDT Mon Sep 1 2025 Troughing is expected to continue across the much of the eastern half of the country over the next week as ridging near Bermuda is blocking it from going much of anywhere. As shortwaves rotate through the mean trough axis over the Great Lakes, it may reorient the trough a bit from time to time, but the mid level flow over our area will remain northwesterly. With no prolonged periods of onshore low level flow, moisture levels are expected to remain near or below (mainly below) climatological norms for the first week of September, for the most part around 1.5 inches. Anything more than isolated convection for the second half of the week into next weekend will be a bit surprising. With the lowered moisture levels, that should allow temperatures to warm fairly efficiently, especially when surface winds are northerly. This should produce high temperatures in the lower 90s, and wouldn`t be surprised to see one or two spots in the mid 90s. Even so, with dew points in the 60s, or perhaps lower 70s, this wouldn`t produce oppressive heat index readings. Overnight lows could be near to slightly below normal next weekend. Some indications of even drier air feeding into the area by next Sunday and Monday (9/7-8) by both the operational GFS and ECMWF. && .AVIATION... (06Z TAFS) Issued at 1200 AM CDT Mon Sep 1 2025 VFR conditions in place. That`s likely to continue through the overnight hours, and probably the daytime hours on Monday as well. While there will likely be some cumulus development on Monday, temperature/dew point spreads indicate that cloud bases should be above FL030 for much or all of the daytime hours. If any thunderstorms develop at all near the terminals, it would be at KHUM, and even there, areal coverage looks to be isolated, with probabilities too low to justify mentioning in the forecast that far out. && .MARINE... Issued at 1200 AM CDT Mon Sep 1 2025 Daily thunderstorms remain the main issue over the open coastal waters as a stalled front lingers just south of the local waters. Expect brief bursts of stronger winds and higher waves in and near storms. The boundary pushes farther into the Gulf today, with offshore flow holding through at least midweek. With northeasterly winds around 15 knots expected across portions of the eastern coastal waters anticipated during the daytime hours today, will raise Small Craft Exercise Caution headlines for those waters, similar to yesterday, ending at 00z Tuesday. && .PRELIMINARY POINT TEMPS/POPS... MCB 89 68 88 67 / 10 10 30 10 BTR 91 71 90 69 / 10 10 30 10 ASD 89 69 88 68 / 10 10 30 10 MSY 90 76 90 75 / 20 10 40 10 GPT 88 70 88 70 / 10 10 20 10 PQL 89 67 88 67 / 10 10 20 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RW LONG TERM....RW AVIATION...RW MARINE...RW