Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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843 FXUS64 KLIX 282347 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 647 PM CDT Sun Apr 28 2024 ...New AVIATION... .SHORT TERM... (This evening through Monday night) Issued at 311 PM CDT Sun Apr 28 2024 Some isolated showers and occasional thunderstorm is ongoing now though the next few hours due to some warm advection but not a lot of environmental support for these storms so they should be fairly weak and short lived with a few spots accumulating up to maybe 0.1 in of rain. Otherwise, the other concern for the very short term is the elevated gusty winds due to a tightened pressure gradient between low pressure up to our northwest and high pressure to our east. With high pressure drifting eastward, winds have decreased slightly. But still is gusty at times, so will let the current wind advisory ride though expiration. Also, due to the southeasterly winds, eastern facing shores will have some slight coastal flooding issues with the wind piling the water up during a high tide cycle later this evening. Tides should peak early tonight and then begin dropping. As the winds should be on the decrease by the time the next high tide cycle rolls though, it`ll be allowed to expire this evening. Moving into tomorrow morning, a line of convection is forecasted to move though the area. Timing is still a bit uncertain as it depends on the formation of convection in eastern Texas and how quickly it then moves here. Right now there are a few storms starting to bloom up at the tail end of a decaying line of convection near eastern TX/western LA. CAMs currently have the line coming in a bit earlier (14-15z in entering the CWA) but the globals/NBM has it a bit later. Biggest concern for this line will be the potential for heavy rain. Although it has been relatively dry (other than today), these storms will likely be efficient rainmakers. PW values of around 1.3-1.5in and 1000-1500 J/kg CAPE should be sufficient to maintain these storms along with forcing from a shortwave passing though Arkansas/N Louisiana. Biggest unknown will be just where the heaviest rain will drop. Although this line should be relatively progressive, highly efficient rainfall could easily overwhelm localized areas. The best severe convective potential appears to be just to our west but definitely can`t rule out some strong storms or maybe a severe one or two. As it continues to push eastward into our area, the environmental support will continue to decrease so the current thinking is it`ll weaken as it moves eastward towards Mississippi but if it gets organized enough in east TX/west LA it could maintain itself a bit further. Once the line passes though it`ll have a minor impact on the lows tomorrow night. && .LONG TERM... (Tuesday through Saturday night) Issued at 311 PM CDT Sun Apr 28 2024 Going into the day on Tuesday, we get right back into onshore return flow following showers/storms the day prior, with isolated showers around within increasing deep rich Gulf return flow. No adjustments needed against NBM PoPs introducing around 30-40% chances primarily in the afternoon following peak diurnal heating. Might see a few intervals of disorganized showers/storms again on Wednesday in a progressive WSW/ENE flow and embedded subtle H5 impulses ride the flow, but the main storm track will remain well to our west and north as ridging dominates the SE US, providing multiple rounds of severe weather targeting the Plains states. Seeing some long-range trends hint at a front slowing/stalling across the area late week into the weekend, and with persistent H5 impulses riding the quasi- zonal flow aloft may introduce periods of showers/storms, perhaps an uptick in coverage this weekend. Too soon to narrow down timing/specifics, but will mention that there are no major indications of widespread heavy rain/severe weather outside of hit- or-miss shower/storm chances. Otherwise, only notable edits in the long range were to nudge up temperatures slightly above deterministic suggested values, with many areas reaching the mid 80`s to some upper 80`s especially by late week, persistently around 3-8 degrees above average for this time of the year. && .AVIATION... (00Z TAFS) Issued at 642 PM CDT Sun Apr 28 2024 Patchy MVFR ceilings are impacting most terminals this evening as low-level moisture advection continues across the area. Expect the MVFR ceilings to become more widespread overnight as the moisture pools ahead of an approaching thunderstorm complex. The complex should impact the western terminals by late morning and will impact all terminals throughout the morning and afternoon as it progresses eastward. When the line of storms passes, expect mostly 30-40 mph westerly gusts with it. After the complex exits in the early evening, MVFR ceilings look to hang around in its wake, and gusty southeast flow resumes. && .MARINE... Issued at 311 PM CDT Sun Apr 28 2024 Strong winds up to 35-40 knots remain on the coastal waters through late tonight before winds start to slowly decrease. Showers and thunderstorms are expected tomorrow morning as a line is forecasted to pass though the area from the early to mid morning hours though the afternoon. By the time it makes it to the Gulf waters, it likely will not be too strong but can`t completely rule that out. There might be a need for exercise caution headlines at some point tomorrow night, but overall the conditions will become more benign with light onshore flow. -BL && .PRELIMINARY POINT TEMPS/POPS... MCB 67 78 62 84 / 10 90 60 40 BTR 70 82 66 87 / 20 90 40 50 ASD 70 83 65 85 / 10 80 60 50 MSY 72 83 68 84 / 10 80 50 50 GPT 70 81 66 82 / 10 60 60 50 PQL 67 83 65 84 / 0 40 50 40 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...Wind Advisory until 8 PM CDT this evening for LAZ034>037-039- 046>048-056>060-064>071-076>090. Coastal Flood Advisory until 7 PM CDT this evening for LAZ058- 070-076-078-080-082-084. GM...Small Craft Advisory until 7 AM CDT Monday for GMZ530-532-534- 536-538-550-552-555-557-570-572-575-577. MS...Wind Advisory until 8 PM CDT this evening for MSZ068>071-077- 083>088. Coastal Flood Advisory until 7 PM CDT this evening for MSZ086>088. GM...Small Craft Advisory until 7 AM CDT Monday for GMZ532-534-536- 538-550-552-555-557-570-572-575-577. && $$ SHORT TERM...BL LONG TERM....KLG AVIATION...JZ MARINE...BL