Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Sep 14 2023 22:55:02 AWUS01 KWNH 142254 FFGMPD KSZ000-NEZ000-COZ000-150430- Mesoscale Precipitation Discussion 1070 NWS Weather Prediction Center College Park MD 654 PM EDT Thu Sep 14 2023 Areas affected...central High Plains Concerning...Heavy rainfall...Flash flooding possible Valid 142253Z - 150430Z Summary...Flash flooding will be possible over parts of the central High Plains through 04Z with rainfall rates of 1-2 in/hr with slower moving cells. Discussion...22Z regional radar imagery across the central High Plains showed a broken line of thunderstorms located along a frontal boundary that stretched from southwestern NE to just south of the Palmer Divide. Additional showers and thunderstorms were located along the Front Range, moving eastward into the Great Plains. Moisture across the region was anomalous with standardized anomalies of precipitable water ranging between +1 and +2, while 22Z SPC mesoanalysis data indicated 500-1000 J/kg MLCAPE across northeastern CO, along and just behind the cold front. Aloft, a positively tilted shortwave trough was noted to be advancing east across a line extending from central WY into southern NV, with a 40-60 kt upper level jet max located from the central CO/WY border into SD. The cold front is expected to continue advancing slowly southward over the next several hours with some component of low level upslope flow in its wake. Showers and thunderstorms will continue to form within the low level convergence axis near the front and advance off of the higher terrain into the High Plains within the instability axis where weak (10 kt or less) 0-6 km AGL layer winds will promote some slow cell movement. While even elevated instability is forecast to lower from west to east and north to south through 03Z in the wake of the front, increasing right entrance region upper level jet ascent and diffluence is expected to set up over the next 3-6 hours across east-central and northeastern CO which may overlap with pockets of lingering instability to support higher rainfall rates. 1-2 in/hr rain rates are expected at times over the next few hours with the potential for flash flooding within areas of lowered FFG (1-2 inches per hour). Dry antecedent conditions for this portion of CO over the past 1-2 weeks should limit the coverage of flash flooding to localized areas. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9pjBnLT8QEre3gmRgFw4notN-luEbeWeJum-aXPxyRGYim-_kHYOkfB_oiP5QON_MkDm= 4jkMmP_HmNKt2c0QCb8PFyM$ for graphic product... ATTN...WFO...BOU...GLD...LBF...PUB... ATTN...RFC...ABRFC...MBRFC...NWC... LAT...LON 41230220 40310146 39030237 38420347 38420498=20 38670543 38890553 39240551 39770524 40040416=20 40610304=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .