Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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745 FXUS64 KLIX 080841 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 341 AM CDT Wed May 8 2024 ...NEW SHORT TERM, LONG TERM, MARINE... .SHORT TERM... (Today through Thursday Night) Issued at 330 AM CDT Wed May 8 2024 Today will be a rather dry day across the region with most of the upper support in the active SW flow aloft staying to our north over the Midsouth and Tennessee River Valley. The story already this morning is just how muggy and warm it is outside. At the time of this AFD in the middle of the night, temperatures are still around 80F with dew points of 75F leading to a heat index of 85F...Keeping in mind it`s still early May. Today we should warm a good bit into the lower and middle 90s. Low level flow will remain out of the south today meaning immediate coast will remain slightly cooler than inland zones. On Thursday a strong upper level shortwave will help send a cold front southward toward the region. During the afternoon, in response to a modest impulse over central TX, clusters of showers and thunderstorms are expected to develop along the I35 corridor and slide eastward within the flow that over our location should become more zonal as the parent trough aloft continues to evolve/amplify upstream. These clusters of storms may merge into a QLCS late Thursday and continue downstream across our region. At this juncture, low level shear appears to be very modest, but instability will be on the more moderate to higher end. Globals and mesoscale models have this QLCS moving through in the early morning hours generally along and north of the I-12/10 corridor. This is where SPC has delineated a slight risk of severe thunderstorms (marginal elsewhere) in the SWODY2. Primary concern will be strong gusty winds with bowing signatures where mean flow crosses the QLCS perpendicularly. Additionally, with a bit higher instability, cannot ignore at least a low-end severe hail threat as well but this will likely be a secondary concerns. Finally, given the transient nature of the QLCS, think that flooding potential will be minimal outside of of typical poor drainage areas within Baton Rouge. We`ll also need to watch the cold pool dynamics and how it may impact the speed for the cold front. It wouldn`t be out of the realm of possibility that the cold pool will help motivate the FROPA a bit sooner than currently forecast. (Frye) && .LONG TERM... (Friday through Tuesday) Issued at 330 AM CDT Wed May 8 2024 Any residual shower/storm activity lingering over from the short term period will quickly exit stage east and south. At the surface, the cold front will continue to drop southward as an upper level Canadian trough continues to amplify over the eastern U.S. With lower heights and thicknesses along with low level CAA, temperatures will be slightly cooler on Friday. That said, above average temperatures are anticipated to continue especially closer to the coast. Despite the weak CAA, strong insolation/sun angle will help keep things on the warm side. Going into the weekend, a more progressive pattern takes over. Temperatures start out around average on Saturday and Sunday with a more zonal flow over the region. However, all eyes begin to shift upstream later into Sunday. The next H5 shortwave, this one with Pacific roots, will migrate over the high plains. This will help the front that pushes through late in the short term period or early in the long term period lift back closer toward our region. With surface convergence and perhaps some help from isentropic upglide, POPs increase later into the weekend and especially to start the new workweek. One question is how far north the front will get and how progressive the H5 trough will be. The surface high takes some time to migrate eastward into the Mid Atlantic states this weekend and so return flow will be limited initially. That said, a very moisture rich environment isn`t far and with the front lifting northward it wouldn`t take long to moderate the low level moisture profile. Going deeper into the new workweek next week, it appears that a series of upper level impulses within the flow move over our region leading to perhaps periods of showers and thunderstorm activity. Models are still in a bit of a disagreement with the exact strength of upper level features and any surface trough/low development that takes place across the northern Gulf, but feeling a bit more confident with strong QPF signals despite the slight disagreements amongst the ECM and GFS. Needless to say with the increase in cloudiness and rainfall, temperatures will be held down or more closer to climo norms. (Frye) && .AVIATION... (06Z TAFS) Issued at 1152 PM CDT Tue May 7 2024 Moist boundary layer conditions will continue through the entire forecast period, and this will keep a scattered to broken deck of strato-cumulus ranging between 2000 and 3000 feet in place through the afternoon hours. Later tonight, mainly between 08z and 14z, another weak inversion will form within the boundary layer. The development of this inversion will allow for lower stratus of 1000 to 1500 feet to develop at the majority of the terminals. However, at MCB, further stratus build down could occur due to a stronger inversion layer, and period of IFR ceilings ranging from 300 to 800 feet is in the forecast between 09z and 13z. Increased thermal mixing after 15z will allow the stratus deck to mix back out into the scattered to broken MVFR deck much as seen Tuesday. (ME) && .MARINE... Issued at 330 AM CDT Wed May 8 2024 Winds will gradually increase today through Thursday with cautionary headlines needed up until a cold frontal boundary passes through the region early Friday. Behind the front, moderate winds and seas will continue with northerly flow developing. This northerly flow will begin to breakdown quickly going into the upcoming weekend as surface high pressure begins to settle across our local waters. (Frye) && .PRELIMINARY POINT TEMPS/POPS... MCB 90 72 90 66 / 10 10 20 60 BTR 93 76 94 72 / 0 0 10 30 ASD 91 74 93 71 / 0 10 10 40 MSY 90 77 93 75 / 0 0 10 30 GPT 86 75 89 70 / 0 10 10 40 PQL 88 74 90 69 / 0 10 10 40 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...RDF LONG TERM....RDF AVIATION...ME MARINE...RDF