Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jul 07 2023 03:28:24 AWUS01 KWNH 070328 FFGMPD OKZ000-KSZ000-COZ000-070930- Mesoscale Precipitation Discussion 0649 NWS Weather Prediction Center College Park MD 1127 PM EDT Thu Jul 06 2023 Areas affected...High Plains of Colorado and Kansas Concerning...Heavy rainfall...Flash flooding possible Valid 070330Z - 070930Z Summary...Supercells developing over eastern Colorado will gradually organize into an MCS overnight and drop southeast into Kansas. Rainfall rates of 2-3"/hr are likely, which despite fast motion could produce 2-3" of rain with locally higher amounts. Flash flooding is possible. Discussion...The GOES-E IR imagery this evening over the High Plains of CO depicts rapidly cooling cloud tops associated with a cluster of strengthening supercells. These storms are developing withing extreme thermodynamics characterized by PWs of 1.25-1.5 inches, above the 90th percentile for the date, collocated with MUCAPE of 2000-3000 J/kg and high values of normalized CAPE indicating large and efficient updrafts. Moist inflow at 850mb into the region measured by regional VWPs is impressive from the S/SE at 20-30 kts, resupplying thermodynamics to allow ongoing convection to continue to intensify and move southeast with time. Impressive effective bulk shear of 50-70 kts is driving the current supercells with radar estimated rain rates of 2-3"/hr, which has resulted in narrow corridors of FLASH response of 125% in the QPE:FFG ratio. During the next several hours, convection is likely to expand in response to increasing ascent through the intensifying LLJ beneath the LFQ of a zonally oriented jet streak. This will provide favorable ascent and shear to produce clusters of thunderstorms, including supercells, across eastern CO. However, as the night progresses, the high-res is in good agreement this will congeal into a large MCS and then may forward propagate on Corfidi vectors pointed E/SE into the intensifying inflow at 30-40 kts. While this speed should offset some of the flash flood potential, rainfall rates that may reach 3"/hr according to the HREF could still produce 2-3" of rainfall with locally higher amounts in a short period of time. The heaviest rainfall will likely occur along the periphery of this MCS where some confluence/training can occur, which is reflected by HREF EAS probabilities exceeding 30%, indicating the good model consensus in this evolution. This portion of the High Plains has been saturated recently noted by AHPS 14-day rainfall that in many areas has been more than 300% normal, resulting in FFG that is as low as 0.75"/1hr and 1.5"/3hrs. The HREF exceedance probabilities reach above 50% for these thresholds, further highlighting the potential for flash flooding tonight. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8-H_G0yTBf6lWARB2FetUF-c-IoA42rP1a1JAVXuz5KiYSguFS87dGOibCYooAz2TGh8= TqtZcMbqgE8S59bNC2wduVg$ for graphic product... ATTN...WFO...AMA...BOU...DDC...GLD...OUN...PUB... ATTN...RFC...ABRFC...MBRFC...NWC... LAT...LON 39880256 39680114 39199981 38419911 37539883=20 37039918 36919984 37080094 37170161 37380243=20 37860353 38890456 39450438 39800370=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) .