Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/27/21

Area Forecast Discussion
National Weather Service Shreveport LA
958 PM CST Fri Nov 26 2021 .SHORT TERM.../Tonight/ The evening satellite imagery indicates an extensive cirrus shield across much of TX extending E into our region, although this cirrus has thinned/remains thin generally along/N of the I-20 corridor from just W of the DFW Metroplex across E TX and N LA/SW AR. As such, temps have fallen quickly with the setting sun given the very dry air mass in place, with the 00Z KSHV raob depicting a PW of only 0.16 inches. Temps have already neared forecast lows across portions of N LA, with the last couple runs of the HRRR trending colder with more of this area reaching/falling below freezing tonight even with the cirrus shield in place. Have had to lower min temps tonight over N LA and portions of SW AR/SE OK given the current trends, although the cirrus should gradually thicken back up late tonight and especially during the day Saturday as the ample Pacific moisture continues to spread ENE across TX into the region ahead of the closed low over NW Old MX, which will shift NE into far W TX Saturday morning. With temps already in the mid 30s across portions of N LA as of 03Z, have issued a Freeze Warning from Bossier Parish ESE to Ouachita/Caldwell Parishes through 15Z Saturday as many of these areas have yet to reach freezing so far this Fall season (and if so, only very briefly). Have opted to leave Caddo Parish out of the Warning for now as the Nrn half of the parish has already observed freezing temps, and SHV itself has yet to fall to freezing and should remain just above 32 degrees through the overnight hours. However, KBAD as well as the Haughton areas have fallen to 34-35 degrees already, and thus have erred on the side of caution as Bossier City itself and the Srn sections of the parish should see freezing temps. Cigs should continue to thicken during the day Saturday as the column begins to saturate from the top down especially during the afternoon, as large scale forcing and isentropic ascent increases ahead of the opening closed low as it traverses WCntrl and Cntrl TX during the day. In fact, the column should moisten enough such that areas of -RA should reach the ground across portions of E TX by late afternoon. Thus, no changes were needed to pops attm, although temps should gradually begin to fall in the afternoon over E TX as evaporative cooling increases as the precipitation moves into this area. Zone update/Freeze Warning already out...grids will be available shortly. 15 && .PREV DISCUSSION... /issued 545 PM CST Fri Nov 26 2021/ AVIATION... VFR conditions will continue through the 27/00Z TAF period. An extensive cirrus shield over E TX/N LA will begin to expand back NE across extreme NE TX/SE OK/SW AR this evening, with cigs expected to gradually lower by mid to late morning Saturday over E TX as AC cigs develop ahead of areas of -RA that will develop over Cntrl TX. As the air mass begins to saturate from the top down, these AC cigs will spread E into SW AR/N LA after 18Z, with the cigs over E TX lowering to 4-7kft as the areas of -RA move in/reach the sfc. Have inserted prevailing -RA mention for the TYR/LFK terminals at 22Z, and GGG at 23Z, with the -RA expected to affect the remainder of the region Saturday evening. Thus, cigs will eventually become MVFR during the evening over E TX, and possibly TXK/SHV by 06Z Sunday. Lt S winds over E TX/SW AR, and calm winds elsewhere tonight, will become SSW 5-8kts after 15Z. /15/ && .PRELIMINARY POINT TEMPS/POPS... SHV 33 61 46 61 / 0 30 60 10 MLU 31 61 45 61 / 0 10 60 20 DEQ 28 62 41 64 / 0 20 40 0 TXK 35 61 46 62 / 0 20 50 10 ELD 30 60 43 60 / 0 10 50 10 TYR 38 58 46 62 / 0 50 60 10 GGG 35 59 44 62 / 0 50 60 10 LFK 38 58 45 61 / 0 50 60 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...Freeze Warning until 9 AM CST Saturday for LAZ002-003-005- 012>014-021. OK...None. TX...None. && $$ 15
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