AWUS01 KWNH 222049 FFGMPD NEZ000-COZ000-NMZ000-WYZ000-UTZ000-230215- Mesoscale Precipitation Discussion 1113 NWS Weather Prediction Center College Park MD 448 PM EDT Sat Aug 22 2026 Areas affected...central Rockies into the High Plains Concerning...Heavy rainfall...Flash flooding possible Valid 222046Z - 230215Z SUMMARY...Slow moving thunderstorms will be capable of isolated to scattered flash flooding across the central Rockies into the adjacent High Plains through the evening. Rainfall totals of 0.5 to 1.0 inches in 15-30 minutes with 1-2 inch totals are expected. DISCUSSION...2030Z visible satellite and area radar imagery showed widely scattered thunderstorms underway across northern NM into eastern UT, western/central CO and southeastern WY into the adjacent High Plains of WY/CO. The environment across the region contained near average to 150 percent above average moisture per blended TPW imagery from 19Z. MLCAPE was relatively weak over the terrain, about 250-750 J/kg per SPC mesoanalysis data and the 18Z GJT sounding. Instability was higher but mostly capped across the High Plains due to warm temperatures near 700 mb and insufficient moisture in that layer. However, the Rockies were also situated beneath a ridge centered along the CO/NM border with weak cell motions of ~5 kt or less from northern NM into eastern UT and central CO. Wind speeds and shear increase across southeastern WY into eastern CO where greater capping currently exists, but a narrow region of greater instability and weaker inhibition was located along the Front Range into the Laramie Range where some stronger and slower moving cells were observed. Expectations are for continued thunderstorm development over the next couple of hours with slow and erratic movement around the ridge. In addition to slow movement, outflows and storm mergers will likely contribute to briefly enhanced rainfall rates with 15-30 minute totals in the 0.5 to 1.0 inch range. Given effective bulk shear of 25-30 kt from southeastern WY into portions of northeastern CO, better potential for cell organization will exist across these regions but so does forward speed especially with any congealing clusters of cells that should forward propagate, limiting rainfall duration. Isolated to scattered areas of flash flooding will remain a possibility, especially should there be overlap of slow moving cells with sensitive burn scars. Otto ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ABQ...BOU...CYS...GJT...PUB...RIW... ATTN...RFC...FWR...KRF...STR...TUA...NWC... LAT...LON 42720586 42610469 42130407 40790382 39080421 37920438 36880488 36260618 36390794 37350961 38730992 40330926 41900765