Area Forecast Discussion
Issued by NWS Shreveport, LA
Issued by NWS Shreveport, LA
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533 FXUS64 KSHV 080815 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 315 AM CDT Wed May 8 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Wednesday through Thursday) Issued at 258 AM CDT Wed May 8 2024 Key Messages: - Multi-day severe weather threat across the Ark-La-Tex starting this afternoon, through late Thursday night/early Friday morning. - All modes of severe weather will be possible during this period, with specific focus on the threat for large hail and damaging wind. Wednesday-Thursday Morning: Morning surface observations across the Four State Region depict a lifting warm front across the I-30 corridor, supporting an expansive warm sector for deeply rooted convection later this afternoon as frontal based lift, associated with a trailing surface cold front, works across the Southern Plains and into SE Oklahoma, and NE Texas. In the aforementioned warm sector, a volatile environment will prevail as maxT`s climb into the upper 80`s and low 90`s once again this afternoon. Model guidance continues to impress as suggested SBCAPE profiles of 4000 J/kg and greater will exist across much of the Ark-La-Tex. Meanwhile, steep 700-500 lapse rates of 8.0 C/km coexist in a region of moderate deep-layer shear. Given the parameters in place, once initiation does occur, the threat for a few discrete supercells supporting the threat of large hail and damaging wind will be possible within the severe primed environment across portions of NE Texas, SE Oklahoma, and SW Arkansas. Not ruling out the chance for a tornado with any developing supercells, but this remains conditional at this time. As expressed in previous AFD`s leading up to today, convective coverage remains rather uncertain and will likely be this way up until initiation is seen later this afternoon. By the evening, what does evolve should begin to form into a linear storm mode where damaging winds, hail and a conditional embedded tornado threat will exist. There remains some uncertainty how long and how expansive this linear storm mode is before decaying. Model guidance this morning suggests that the proposed linear storm mode collapses as it works into portions of NW Louisiana. For now though, messaging remains the same with the idea that severe storms will be possible through the mid to late evening. Given the severe threat in place this afternoon, an Enhanced risk (level 3 of 5) exists across the I-30 corridor, with a Slight risk (level 2 of 5) south through I-20. This outlook could change in future updates if confidence increases with incoming guidance through the morning. Thursday-Thursday Night: By Thursday morning, the cold front from Wednesday should be located somewhere between the I-30 and and I-20 corridor, slowly advancing southward through the afternoon. Along and ahead of the front, a moisture rich environment will exist, with another primed layer of very generous surface instability and modest deep layer shear for thunderstorms to thrive in if allowed the opportunity to do so. Given the slow southward progression of the front, elected to increase maxT`s along the I-20 corridor and south, citing the chance for some compressional warming before thunderstorms develop once again across central Texas by the mid to late afternoon. These may spread eastward by the evening in the form of a possible multi- cell complex where damaging wind and hail will be the primary threats. This should clear the area by early Friday morning. Given the forecast axis of heavy rainfall along the I-20 corridor and south, a Slight risk of excessive rainfall is being advertised valid 12z Thursday, through 12z Friday. At this time, WPC 3 day QPF values in this region suggest a possible 1-2", not counting the chance for any locally higher amounts. RK && .LONG TERM... (Thursday Night through Wednesday) Issued at 258 AM CDT Wed May 8 2024 The front will be well south of the FA by mid-Friday morning with high pressure settling in behind. Influence of the passing boundary, and high pressure will promote drier conditions through the end of the week and heading in the weekend, with a return to near normal temperatures. Rain chances return through Sunday as shortwave pertubations within the mid-level flow work across Texas and Louisiana. To no suprise, and being this this far out, there remains some uncertainty on where the axis of the heaviest rainfall will set up. That being said, rain chance do return by the end of the weekend into early next week. At the same time, maxT`s will gradually climb back through the low to mid 80`s through the end of the period. Overnight lows will follow a similar trend, climbing through the mid to upper 60`s. RK && .AVIATION... (06Z TAFS) Issued at 1158 PM CDT Tue May 7 2024 MVFR ceilings rapidly returning attm across our airspace and should see these conditions prevailing by the next 2-4 hours. Added VCTS to the TYR/TXK terminals for the next 2-4 hours given convective trends with a weak boundary in place. Otherwise, should see MVFR ceilings climb to low VFR variety by late morning into the afternoon before scattering out all together by late afternoon. Introduced VCTS at the TYR/GGG/TXK and SHV terminals this evening with scattered strong to severe convection expected to develop along the same boundary towards the tail end of the 06z TAF period. Stronger pressure gradient in place today will result in stronger S winds today with sustained winds near 10-14kts with gusts upwards of 25kts beginning after sunrise towards mid morning and continuing through the day. 13 && .PRELIMINARY POINT TEMPS/POPS... SHV 93 73 88 66 / 20 30 30 50 MLU 92 72 90 66 / 10 30 20 50 DEQ 85 62 83 58 / 40 70 30 20 TXK 92 69 86 62 / 30 70 30 30 ELD 90 66 86 61 / 10 50 30 40 TYR 90 72 87 63 / 20 20 40 40 GGG 90 70 87 64 / 20 30 30 40 LFK 90 73 92 66 / 10 10 20 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ SHORT TERM...53 LONG TERM....53 AVIATION...13