Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 22 2023 19:55:02 AWUS01 KWNH 221954 FFGMPD NEZ000-COZ000-WYZ000-230155- Mesoscale Precipitation Discussion 0564 NWS Weather Prediction Center College Park MD 354 PM EDT Thu Jun 22 2023 Areas affected...Central High Plains & Rockies Front Range Concerning...Heavy rainfall...Flash flooding likely Valid 221955Z - 230155Z SUMMARY...Another day of strong-to-severe storms likely to produce flash flooding later this afternoon and evening. Areas most at-risk are areas hit hard from yesterday's barrage of storms, as well as areas with saturated soils from anomalous rainfall the past 2-4 weeks. DISCUSSION...GOES-16 visible satellite is showing a growing field of agitated towering cumulus over the Front Range of the Rockies. Surface analysis shows a frontal boundary draped across southern WY and extending northeast into the Northern Plains, while there is also an outflow boundary working its way west through the Denver metro area. RAP forecasts shows a strengthening 850mb moisture transport out of the southeast will aid in increasing surface dew points and PWATs this afternoon and evening. RAP guidance shows PWs on the eastern periphery of the highlighted region rising as high as 1.25", but most of the region will reside in the 0.75-1.0" range. Instability has continued to rise with MLCAPE largely in the 1,500-2,000 J/kg range. RAP forecasts show up to 40-45 kts of effective bulk vertical wind shear and up to 100-150 m2/s2 of sfc-3km SRH. These parameters are not too far off from yesterday's that supported supercells initially, followed by congealed multicell clusters that were highly efficient rainfall producers. Aside from the favorable atmospheric parameters for excessive rainfall rates that could top 2"/hr in some cases, soils are even more sensitive after yesterday's heavy rainfall. MRMS soil saturation shows portions of east-central CO are up to 50-75%. AHPS 7-day rainfall totals are now >600% of normal along the Palmer Divide and into portions of southeast WY. Far western NE also sports 14-day rainfall totals that are 300-400% of normal. Latest 1-hr FFGs along the Palmer Divide and the I-70 corridor from Denver on east are <1". This is also the case along the Front Range in southeast WY north of Laramie and Cheyenne. These storms will have no problem being able to produce hourly rainfall rates above the present FFGs. The more heavily urbanized cities within this highlighted region are also more prone to potential flash flooding given their greater concentration of hydrophobic surfaces. For these reasons, flash flooding is likely to occur in parts of the region this afternoon and evening with potential travel disruptions during the evening rush hour possible.=20 Mullinax ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8JyXNNY-AKNr328Wf3IzMgJN0IsYnKLnRSCvTGKaMmzcslUOHDibd3IwhFxuL4-yzI18= 8BGZGMw1hAL7ooqyG9_F4_8$ for graphic product... ATTN...WFO...BOU...CYS...GLD...PUB... ATTN...RFC...ABRFC...CBRFC...MBRFC...NWC... LAT...LON 42930376 42110325 40620263 39430250 38810346=20 38640472 38860538 39740558 40470596 41620626=20 42660535=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) .