Area Forecast Discussion
Issued by NWS Shreveport, LA
Issued by NWS Shreveport, LA
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910 FXUS64 KSHV 200738 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 238 AM CDT Mon May 20 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Monday through Tuesday) Issued at 127 AM CDT Mon May 20 2024 Persistence remains the best forecast tool through the short-term as this stagnant weather pattern is forecast to continue across the Southern Plains/Lower Miss Valley. Upper ridging remains entrenched across the Ohio and Tenn Valleys, into the Lower Miss Valley with a longwave trough noted across the Pacific Northwest into the southwest Great Basin. This ridging will remain in place for the most part tonight into Tuesday as pieces of energy rotate out of the upstream longwave trough, remaining well north and west of our region. The lack of any kind of forcing, either in the low or mid levels due to the suppressing influence of the upper ridge axis despite increasing diurnally driven instability, will result in virtually no rain chances in the short term. Concerning temperatures, stayed on the higher side of guidance today given recent trends. Even with the induction of southerly winds today, should see a little mixing down of afternoon dewpoints given slightly lower pwats in place. Those pwats will increase for Tue which will result in less mixing and higher afternoon dewpoints and thus, higher heat indices. Afternoon heat indices on Tuesday will likely approach triple digits across some locations given the higher dewpoints in place with ambient temperatures mostly in the lower to middle 90s. 13 && .LONG TERM... (Tuesday Night through Monday) Issued at 127 AM CDT Mon May 20 2024 By Wednesday, the upper ridge axis gets shunted to our east and this will allow for more in the way of upscale forcing from the broad trough across the Great Basin. Upper flow will become southwesterly aloft and ripples in this flow will allow for the upper forcing necessary for scattered convection across our northwest half Wed thru Thu. Coverage may be a little greater Wed Night into Thu depending on the proximity of a cold front that appears to pull up stationary just northwest of our far northwest zones by sunrise Thu Morning. Diurnally driven instability will result in some of the storms across our north and northwest zones Wed and Thu aftn/evng becoming strong to severe thus the SPC Slight Risks for severe thunderstorms both days. There appears to be a stronger forcing signal perhaps impacting more of our region late Thu/Thu Night bringing with it the possibility of more widespread convection with heavier rainfall across at least our northern half before it exits the region towards sunrise Fri Morning. Kept low pops in the fcst Fri into Sat across mainly our northern half even through forcing appears to be weaker than what our region will have experienced Wed into Thu. With less in the way of rain chances, that will result in hotter temperatures with ambient readings well into the 90s both Sat into Sun with triple digit afternoon heat indices across our southwest half Sat and nearly areawide by Sun into Mon. There appears to be a upper level pattern change just beyond this 7-day forecast as the broad upper trough across the Great Basin to our west gets replaced with strong upper ridging across the Intermountain West with the broad trough migrating eastward into Upper Midwest into the Great Lakes. The closer we get to June, this introduces northwest flow aloft season and the influx of MCSs across the Southern Plains. We will watch this flow very carefully through much of next week. 13 && .AVIATION... (06Z TAFS) Issued at 1240 AM CDT Mon May 20 2024 Patchy fog may result in a brief window of MVFR visibilities between 20/09z-20/14z, especially at KMLU and KLFK. Any fog that develops should quickly dissipate after sunrise. Otherwise, VFR flight conditions should prevail at all terminals through the remainder of the TAF period with scattered daytime cu expected between 4 and 6 kft. CN && .PRELIMINARY POINT TEMPS/POPS... SHV 94 73 93 76 / 0 0 0 0 MLU 92 70 91 72 / 0 0 0 0 DEQ 91 68 90 72 / 0 0 0 10 TXK 92 71 92 75 / 0 0 0 0 ELD 91 69 91 72 / 0 0 0 0 TYR 92 72 91 75 / 0 0 0 0 GGG 92 71 91 75 / 0 0 0 0 LFK 92 71 93 75 / 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ SHORT TERM...13 LONG TERM....13 AVIATION...09