Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jul 31 2023 19:18:42 AWUS01 KWNH 311918 FFGMPD COZ000-WYZ000-010115- Mesoscale Precipitation Discussion 0821 NWS Weather Prediction Center College Park MD 317 PM EDT Mon Jul 31 2023 Areas affected...Northern CO...Southern WY Concerning...Heavy rainfall...Flash flooding possible Valid 311915Z - 010115Z SUMMARY...Developing thunderstorms along the Front Range could cause flash flooding this afternoon, particularly in areas with sensitive soils and in more heavily urbanized communities. DISCUSSION...GOES-16 visible satellite imagery showed towering thunderstorms forming over the northern Colorado Rockies with additional storms forming along the higher terrain of south-central Wyoming. These storms are forming downwind of a shortwave trough tracking into northeast UT and on the northern periphery of an upper level ridge axis positioned over the southern High Plains. As daytime heating continues, the atmosphere will grow increasingly more unstable. Latest RAP forecasts show close to 500 J/kg available in the northern Colorado Rockies and into south-central WY, while MLCAPE rises to 1,000-1,500 in lee of the Rockies. These areas in lee of the Rockies also sport >60F dew points. These more-than-sufficient instability values and dew points reside within an environment where PWs could approach and even top 1" this afternoon, which are at or above the 90th climatological percentile for much of the highlighted region. Mean 850-300mb winds are light and out of the SW over northern Colorado. Latest RAP mesoanalysis shows wind speeds as light as 5 knots, allowing for meandering storms to produce heavy amounts of rainfall in a short period of time. Storm motions are closer to 10 knots farther north into WY. With ample moisture, sufficient instability, and slow moving storm motions, hourly rainfall rates could top 1.5". The 12Z HREF does show 30-40% probabilities for 3-hr QPF > 3-hr FFGs in parts of northeast Colorado and far southeast WY by late afternoon and early evening. Some soils remain overly saturated thanks for rainfall totals >300% of normal over the past 7 days according to AHPS. Flash flooding is possible this afternoon in locations featuring more sensitive soils most at-risk. There is also the potential for flash flooding in burn scars, along complex terrain, and in more urbanized communities. Mullinax ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-0yJ4ugZa7fYb14RIDcFMLkSolZc8hAo13y5AG9qEhR6_8z1zY4pYDK6hXqVozjNkeVO= QDVvR7c0zD-Y0LUquUKfDG8$ for graphic product... ATTN...WFO...BOU...CYS...GJT...PUB... ATTN...RFC...ABRFC...CBRFC...MBRFC...NWC... LAT...LON 42410597 42240493 41310453 40540449 39680471=20 39190526 39270674 40860733 42010683=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) .