Flash Flood Guidance
Issued by NWS
Issued by NWS
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104 AWUS01 KWNH 272017 FFGMPD COZ000-NMZ000-AZZ000-UTZ000-280215- Mesoscale Precipitation Discussion 0506 NWS Weather Prediction Center College Park MD 416 PM EDT Thu Jun 27 2024 Areas affected...Portions of Western Colorado & Northwest New Mexico Concerning...Heavy rainfall...Flash flooding likely Valid 272015Z - 280215Z SUMMARY...Flash flooding likely as strong forcing coupled with record atmospheric moisture fuels storms capable of heavy rain rates to 2 inches per hour. DISCUSSION...Numerous showers and thunderstorms have developed across Utah, Arizona, and far western New Mexico this afternoon. A strong shortwave trough moving east over the northern Rockies is invigorating the atmosphere over the Four Corners. Storms capable of rainfall rates as high as 2 inches per hour have developed, and will continue to redevelop and form over western Colorado and Northwest New Mexico into the afternoon. A major contributing factor to the unusual nature of convection in this region are record to near record precipitable water values from the 12Z soundings this morning based on SPC Sounding Climatology in Albuquerque, Grand Junction, and Salt Lake City. Thus, the storms have unusually high amounts of moisture to work with, and the shortwave trough will help those storms to organize as they interact with the high terrain. Further, SBCAPE values of 1,000 to 2,000 J/kg already in place will continue to support strong thunderstorm development through the afternoon and early evening. The entire Four Corners region has above to well above normal soil moisture from recent days of rain, so the organized and stronger nature of the storms developing will combine with already higher than normal river levels to result in scattered instances of flash flooding. The storms that develop over local burn scars will cause locally considerable and significant flash flooding over and immediately downstream of the burn scars. CAMs guidance shows portions of western Colorado will be targeted by the convection currently over Utah as they move into Colorado through this afternoon. The storms may be a bit faster moving this afternoon as compared with previous days, but favorable dynamics for training/backbuilding and the aforementioned wet soil conditions as well as interaction with terrain will all support flash flooding development. Storms capable of causing flash flooding are likely to be ongoing beyond the time of this MPD, so an updated MPD is expected around 02Z/8pm MDT. Wegman ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ABQ...FGZ...GJT...PUB...SLC... ATTN...RFC...ABRFC...CBRFC...WGRFC...NWC... LAT...LON 40170736 39890669 39520649 38500623 37750574 36500559 35490588 35160755 36090805 36860913 37210943 38010869 38520904 38790961 39360996 39571033 39690969 39930856