Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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263 FXUS64 KLIX 080403 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 1103 PM CDT Sun Jul 7 2024 ...New UPDATE... .UPDATE... Issued at 1046 PM CDT Sun Jul 7 2024 With the evening CWF update, raised the western 2 marine zones (GMZ550-570) from Small Craft Exercise Caution to Small Craft Advisory, as deterministic wind grids have about the western half of both zones at or above 20 knots, with at least some potential for waves approaching 7-8 feet. Will run it through 16z for now, as current wind forecast shows things relaxing a bit by then. Have also bumped PoPs up a little more to the west of a Baton Rouge to Houma line with the feeder band of convection that is riding through the Atchafalaya Basin. While most of it looks focused on the WFO LCH side of the basin, it`ll need to be monitored for heavy rain potential until it moves west or dissipates. Don`t have a lot in the way of ground truth gauges in that area, but with precipitable water values between 2.0 and 2.25 inches, potential for isolated flash flooding cannot be entirely ruled out. && .UPDATE... Issued at 744 PM CDT Sun Jul 7 2024 Updated ZFP was issued to remove today`s Heat Advisory headline. Also bumped up PoPs along the Atchafalaya River Basin a bit with the band of convection over the basin. May need a further update as it is not out of the question that the storms could reach the City of Baton Rouge and other portions of the area. With tropical systems, bands tend to contract toward the center overnight, but haven`t seen any hints that`s happening yet. If a second update looks necessary, will likely issue prior to 9 PM CDT. && .SHORT TERM... (This evening through Wednesday) Issued at 225 PM CDT Sun Jul 7 2024 A broad upper level trough continues to be centered along the midsection of the country from the Dakotas to Oklahoma... encompassing all but the western/eastern fringes of the country. As of 2p, Tropical Storm Beryl isolated in the western Gulf of Mexico, centered roughly 125 miles east of Brownsville Texas. The storm is forecast to continue northwestward this afternoon, making landfall along the Texas coast Monday morning. The CWA is on the outer periphery of Beryl and subsidence from it has been part of the suppression of convection so far this afternoon. The other big factor is dry air wrapping around the eastern side of Beryl. Blended TPW product from GOES Sat has been showing PW around 1.7" and the KLIX 18Z sounding confirmed that, measuring 1.65". The CAMs continue to capture lack of precip in the near term vs global models, which the NBM has been favoring lately. Thus, have trended tonight and Monday morning POPs closer to those drier members of guidance. Then, when it comes to heat, going ahead with a heat advisory for much of the CWA. Left out some SW MS counties and a few adjacent LA parishes as well as northern halves of the coastal MS counties. Might be a little too conservative but lower dewpoints should help limit heat indices somewhat. If surrounding WFO`s do decide to issue a heat advisory, may have to expand ours to simplify public messaging. The biggest thing to watch after this weekend will be isolate areas of heavy rainfall. As the remnants of Beryl are being absorbed by the upper trough to the north and track east across the lower Mississippi Valley. As seen in previous decaying tropical systems tracking northward, models show the trough dragging a tail of rainfall along the eastern side of the remnants extending from the base of the trough/remnant Beryl to well south into the Gulf of Mexico Tuesday through Wednesday. Forecast PW`s in the 2.4-2.6" aren`t surprising and quite concerning, especially when combined with ample instability in place. No way to know where one of these tropical rain bands lines up but with very efficient precip processes expected, certainly could see some surprisingly high streaks of very heavy rainfall. && .LONG TERM... (Thursday through Saturday night) Issued at 225 PM CDT Sun Jul 7 2024 The local area falls into a very typical summertime pattern for the remainder of the week. The broad upper level trough over the majority of the country today will shift eastward Thursday. Strengthening upper ridge in its wake will expand across the Rockies Friday into this weekend. That still leaves the CWA neither under high pressure or troughing. Combine that with normal summer daytime heating and should have scattered to numerous pop-up afternoon thunderstorms. Should see temps lower closer to normal, which will be a nice break from very hot conditions lately. && .AVIATION... (00Z TAFS) Issued at 620 PM CDT Sun Jul 7 2024 All terminals were VFR at 23z. Would note that there is a northward moving band of showers/storms just west of the Atchafalaya River Basin that would only have to shift about 30SM eastward to impact KHUM/KBTR this evening. For now, won`t carry mention in those terminals, but cannot rule out future amendments. Generally, VFR conditions are expected overnight. There should be enough air movement to prevent very low conditions (fog) overnight. MVFR ceilings are possible as the cumulus field develops at mid-morning Monday. Will only mention VCSH at KHUM during the day at this time. Winds may be a bit more of an issue on Monday as pressure gradient increases. Sustained winds near 15 knots likely at western terminals, and wouldn`t be surprised to see gusts exceeding 25 knots. && .MARINE... Issued at 225 PM CDT Sun Jul 7 2024 A broad upper level trough is centered along the midsection of the country and encompasses all but the western/eastern fringes of the country. Also, Tropical Storm Beryl is located in the western Gulf of Mexico, centered roughly 125 miles east of Brownsville Texas. The storm is forecast to continue northwestward this afternoon, making landfall along the Texas coast Monday morning. The overall size and wind field of Beryl is quite a bit smaller in size compared to Alberto from June. This has and will limit the extent of stronger winds locally. Marine obs today have persistently shown generally light southeasterly with exercise caution speeds only west of the mouth of the MS river. That should continue to be the case through Monday. Monday night into Tuesday night, exercise caution conditions will spread across more of the local area as the remnants of Beryl eject northward. Beyond that, benign conditions return to the coastal waters. && .PRELIMINARY POINT TEMPS/POPS... MCB 74 93 75 90 / 10 60 40 100 BTR 79 97 80 94 / 30 60 60 100 ASD 77 94 79 92 / 10 60 50 100 MSY 80 94 81 92 / 10 60 60 100 GPT 79 92 79 91 / 10 60 60 100 PQL 77 95 79 94 / 10 60 40 100 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...Heat Advisory from 11 AM to 7 PM CDT Monday for LAZ034>036- 046>048-056>060-064-065-070-076>090. GM...Small Craft Advisory until 11 AM CDT Monday for GMZ550-570. MS...Heat Advisory from 11 AM to 7 PM CDT Monday for MSZ068-086>088. GM...Small Craft Advisory until 11 AM CDT Monday for GMZ570. && $$ SHORT TERM...ME LONG TERM....ME AVIATION/UPDATES...RW MARINE...ME