Area Forecast Discussion
Issued by NWS Shreveport, LA
Issued by NWS Shreveport, LA
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573 FXUS64 KSHV 122032 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 332 PM CDT Sun May 12 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (This evening through Monday Night) Issued at 332 PM CDT Sun May 12 2024 The afternoon sfc analysis indicates a warm front that extends from near LCH W to just N of IAH to just S of CLL and ATT as of 1930Z, with only a slightly Nwd jog of this bndry noted since this morning. With the convection having become widespread N of the bndry across much of Cntrl/N TX into Nrn, Cntrl, and SW LA, the rain cooled air should not allow for much Nwd return this evening, until the convection begins to diminish later this evening as drier mid level air over far W TX begins to entrain E across N TX ahead of upper troughing that will drift E into Wrn/Cntrl KS and the TX Panhandle. While the severe threat has diminished slightly since this morning, still seeing a narrow swath of deeper convection still ongoing from Houston County TX SE through Srn Cherokee, Nacogdoches, Angelina, and San Augustine Counties, associated with stronger convergence along an H850 inverted trough extending from Cntrl TX SE into Deep E TX/SW LA. This bndry is progged to lift N through E TX/N LA this evening, which would focus the greater potential for heavier rainfall before weakening overnight. The greater rainfall amounts have been largely focused across Angelina, San Augustine, and Sabine Counties in Deep E TX, with totals ranging from 1.25 to 2.00+ inches, with additional amounts of 1-3 inches possible across the Flood Watch area through Monday evening. Left the Watch area as is, but did add Grant and La Salle Parishes as the various CAMs suggest that some of the higher totals potentially affecting this area tonight. After the break in the convection later tonight, will have to await for the primary upper trough axis to rotate through the Red River Valley Monday, which will reinforce a weak cold front SE into Ern OK/Nrn and Cntrl TX during the afternoon. Large scale forcing is expected to increase especially from midday through the afternoon, with some insolation resulting in increased sfc-based instability accompanied by steep lapse rates aloft, with a potential MCS developing as it shifts ESE across E TX/portions of N LA. Large hail and damaging winds will be possible across these areas, with a renewed threat for heavy rainfall as it spreads SE across the Flood Watch area. This convection should diminish during the evening, with the potential for the Watch area to be cancelled early as drier and more stable air spreads SE in wake of the weak cold fropa. 15 && .LONG TERM... (Monday night through next Saturday) Issued at 332 PM CDT Sun May 12 2024 A brief drying trend is in the offing Tuesday and Wednesday in wake of the fropa, with near normal temps and slightly lower RH`s expected. Weak upper ridging is progged to build E over the region during this time, before a SW flow aloft commences ahead of troughing that will develop from the Great Basin into the Rockies, absorbing a weak closed low over Srn CA/Nrn Baja. Shortwave energy ejecting NE ahead of this trough will yield increasing convection across TX Thursday where a more substantial increase in low level moisture will be, with pieces of this convection eventually spreading E into the region during the day. Any severe potential will be largely dictated any return instability that develops as the deeper low level moisture will be a bit slower to arrive, before the primary trough itself arrives Thursday night resulting in more numerous and potentially deeper convection. This trough may result in this weak sfc front to drift SE through the area Friday afternoon/night, but remains largely uncertain whether it will have enough momentum to exit the area, or possible stall over E TX/N LA and thus maintain unsettled weather as we move into next weekend. 15 && .AVIATION... (18Z TAFS) Issued at 1216 PM CDT Sun May 12 2024 For the 12/18Z TAF update, active weather will continue through most of the period with VCTS/-TSRA likely to keep MVFR/IFR vis/cigs through 13/06Z. A lull from precipitation at 13/06Z-14Z will allow cigs to build in at IFR airspace-wide before the next batch of VCTS/-TSRA arrives right before the end of the period. /16/ && .PRELIMINARY POINT TEMPS/POPS... SHV 67 83 65 84 / 90 50 30 0 MLU 65 82 65 85 / 100 60 50 10 DEQ 63 79 59 82 / 60 50 20 10 TXK 64 80 62 83 / 80 40 20 10 ELD 63 79 62 82 / 90 40 40 10 TYR 66 83 62 84 / 70 40 10 0 GGG 65 83 63 84 / 80 40 20 0 LFK 67 85 65 87 / 80 50 20 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...Flood Watch through Tuesday morning for LAZ001-002-010-011-017- 018-020-022. OK...None. TX...Flood Watch through Tuesday morning for TXZ124>126-136>138- 149>153-165>167. && $$ SHORT TERM...15 LONG TERM....15 AVIATION...16