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Flash Flood Guidance
Issued by NWS
Issued by NWS
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289 AWUS01 KWNH 132153 FFGMPD COZ000-WYZ000-AZZ000-UTZ000-IDZ000-140229- Mesoscale Precipitation Discussion 0877 NWS Weather Prediction Center College Park MD 553 PM EDT Tue Aug 13 2024 Areas affected...Intermountain West Concerning...Heavy rainfall...Flash flooding possible Valid 132152Z - 140229Z Summary...Scattered convection continues across the Intermountain West. Maintenance of storms within a region of comparatively higher buoyancy and PWATs will continue the threat of isolated to scattered flash flooding through this evening. Discussion...Radar and satellite mosaic across the Intermountain West continue to track scattered thunderstorms along the western flank of an elongated monsoon moisture plume. Over the last several hours, several Flash Flood Warnings and reports of flash flooding have occurred as these cells periodically trained with maximum estimated rainfall rates of 1-1.5"/hr. The efficient, training nature of these cells likely remain tied to several factors, including 1-1.1" PWATS (above the 90th percentile for the region), 1000-3000 J/kg of MUCAPE, and unidirectional wind profiles organized with sufficient speed shear to support some organization and longevity of individual cells. Accordingly, these storms with 1-1.5"/hr rainfall rates are expected to continue through the next several hours as this favorable environment interacts with several shortwave perturbations and strengthening left exit forcing from a jet-streak approaching from the west. Thus, the risk of isolated to scattered flash flooding will continue for the next several hours before loss of daytime heating results in a decline in convective coverage and intensity. As usual, slot canyons and burn scars remain particularly sensitive to rainfall impacts. Asherman ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...FGZ...GJT...PIH...RIW...SLC... ATTN...RFC...CBRFC...MBRFC...NWRFC...NWC... LAT...LON 43621246 43610971 39650860 36810975 36481203 37241260 39781229 42231292