Area Forecast Discussion
Issued by NWS Shreveport, LA
Issued by NWS Shreveport, LA
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408 FXUS64 KSHV 162309 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 609 PM CDT Mon Sep 16 2024 ...New AVIATION... .SHORT TERM... (This evening through Tuesday Night) Issued at 126 PM CDT Mon Sep 16 2024 The synoptic scale pattern this afternoon is characterized by an elongated area of low pressure extending from the Mid and Lower MS Valley eastward to the Carolinas, of which contains the remnants of Francine near the AR/MS border and potential tropical cyclone 8 near the NC/SC Coast. This area of low pressure is part of a Rex Block across the Eastern US where high pressure resides above the elongated low over the Great Lakes. A ridge of high pressure is then noted across the Southern Plains in advance of a strong longwave trough over the Western US, where closed low pressure resides over Central CA. In the lower levels, high pressure encompasses a large portion of the NE and Great Lakes region, with closed low pressure associated with the tropical system along the Carolina Coast and a weak sfc trough across the ArkLaMiss associated with Francine remnants. A stationary boundary also remains draped along the eastern slopes of the Rockies S/SE towards and across the Northern Gulf Coast. With the remnants of Francine lingering near the ArkLaTex, skies have been mostly cloudy across most of the CWA. In addition, enough large scale forcing in tandem with daytime heating and rich low level moisture is allowing for the development of scattered rain showers across northern, northeastern, and eastern portions of the CWA. Expect this general area to have the highest rain chances through mid-evening, however, a few light showers may develop just about anywhere. Mid level lapse rates remain rather meager at around 5-6C/km, however, given that the there appears to be at least a weak center of mid level circulation clipping the area, isolated thunderstorms cannot be ruled out. The biggest impacts from today`s weather will be brief, heavy downpours. With the loss of daytime heating after sunset and the continued weakening of the system, scattered shower coverage will become more isolated into the overnight period. Provided the scattered rain showers from Monday, along with continued abundant moisture in the low levels, clouds will be quick to increase and lower overnight tonight into Tuesday morning. Patchy fog is likely to develop, as well patchy areas of light rain and/or drizzle. Conditions will be slow to improve through the morning hours on Tuesday, but will eventually give way to partly to mostly cloudy skies. With the remnants of Francine expected to move back towards the LA Coast, a few rain showers may advect into SE zones with the advance of the sea breeze. Cannot rule out even an isolated shower as far north as the Shreveport/Bossier area. This period of unsettled weather in the short term forecast period will then begin to change heading into the long term forecast period. Kovacik && .LONG TERM... (Wednesday through next Sunday) Issued at 126 PM CDT Mon Sep 16 2024 By Wednesday, Francine remnants will become absorbed by the east to west moving tropical remnants from the Carolina Coast, making for a larger scale area of low pressure east of the MS River. Meanwhile, the pattern will become more progressive across the Western US, helping to push the Southern Plains ridge into the ArkLaTex. This will make for increasing high temperatures back into the 90s and clearer skies. Ensemble guidance/WPC cluster analysis is in good general agreement on Thursday with an upper level ridge over the ArkLaTex and two areas of low pressure to the north and west-one over the Northern Plains and the other off the Central CA Coast. The Central CA trough is expected to dig towards S CA, though there remains some discrepancy towards the extent of the digging and the exact location. But at this point in time, model guidance favors enough digging to the SE to allow for the amplification of the ridge downstream. This points to warmer temperatures on Thursday in the low to mid 90s. This pattern looks to then linger through at least the first half of the weekend as the low jaunts across the desert SW. The low over the desert SW will then begin to lift towards the Central Rockies on Sunday, which is supported by most of the WPC clusters in some fashion. This will help dampen the ridge on its northern periphery. With lee cyclogenesis then expected to take place east of the Rockies, a frontal boundary may then attempt to approach far northern zones at the end of the forecast period. The question will become where the closed mid level low lifts and where subsequent sfc cyclogenesis takes place in regards to when/if a late period fropa can be anticipated. Kovacik && .AVIATION... (00Z TAFS) Issued at 602 PM CDT Mon Sep 16 2024 For the 17/00z TAF update...Radar imagery is showing some isolated rain showers across portions of northern Louisiana, southwest Arkansas and far northeast Texas this evening. This has brought some MVFR CIGs to KELD during the late afternoon hours that should continue into the rest of the evening while the remainder of the area is seeing CIGs between 3-5k feet. I have kept mention of VCSH in for KSHV, KMLU, KTXK, KGGG, and KELD through around 07/02z before this shower activity should start to diminish. I did take all mention of VCTS out at this point because we have not seen much lightning in any of this activity as it has moved through our area. CIGs are going to start to tank around 07/06z for most terminals with widespread MVFR/IFR conditions and some instances of LIFR CIGs at times during the overnight hours. In addition, I do have some mention of BR in for most terminals through the night with visibility around 4-5SM. Last night we did see some locations reach 2SM, however, thinking that might not be the case tonight. /33/ && .PRELIMINARY POINT TEMPS/POPS... SHV 72 86 71 91 / 20 20 0 0 MLU 69 85 67 89 / 20 20 0 0 DEQ 66 86 65 90 / 20 20 0 0 TXK 69 86 69 91 / 20 20 0 0 ELD 66 85 65 89 / 20 20 0 0 TYR 70 89 71 93 / 20 20 0 0 GGG 69 86 70 92 / 20 20 0 0 LFK 69 89 71 92 / 20 20 0 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ SHORT TERM...23 LONG TERM....23 AVIATION...33