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Colorado Flood-A fe w images and thoughts

Colorado Flood-A fe w images and thoughts. Richard Grumm NWS State College PA 16803. Where it rained-black dot is Boulder Stage-IV data; NMQ Q2 and CCPA was used not shown here . When it rained. Timing is EVERYTHING.

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Colorado Flood-A fe w images and thoughts

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  1. Colorado Flood-A few images and thoughts Richard Grumm NWS State College PA 16803

  2. Where it rained-black dot is BoulderStage-IV data; NMQ Q2 and CCPA was used not shown here

  3. When it rained

  4. Timing is EVERYTHING

  5. Why it rained strong ridge weak front easterly flow into terrain convectively favorable environment

  6. Deep moisture PW +4sHow would this look in PDF not s

  7. Easterly flow into the terrain +4s

  8. Pattern of heavy rainfallPontrelli et al 1999: a) Madison County 1995, b) Fort Collins 1997, c) Rapid City 1972 and d) Big Thompson Canyon 1977

  9. Fronts and winds same 4 Cases

  10. Idealized pattern for orographic record rainfall Pre-standardize anomaly era

  11. Predictable? EC Forecasts QPF

  12. EC Patternall models were quite similar

  13. EC PW patternsimilar to SREF/GFS/NAM

  14. EC Windshmm…SREF is next….

  15. SREF WindsLarger anomalies Batman

  16. GFS QPFwhat is a record event in this time frame in the GFS M-CLIMATE?

  17. SREF Probability of 150 mmBoulder is a red dot…..

  18. Prob 100 mm

  19. Mean QPF and 50mm contours by member

  20. SummaryPatterns and Probabilities • Pattern known to be associated with upslope and similar to many heavy rain events involving terrain • Well research and good examples of historic events from the past. • Pattern well predicted by any system we looked at. • Standardized anomalies may have provide clue about high PW and strong easterly flow • Good pattern with good anomaly signature • Trevor could likely provide PDF of the PW and u-winds in affected region • QPF: • variable in spatial and temporal distribution • Many uncertainty issues along with clues to the rainfall potential • EC in key time was not a silver bullet (EC-lite) • We need internal model climatology M-Climate so EFI like products alert use to near record or record QPF in every forecast system verse it’s internal a climate • Link: http://cms.met.psu.edu/sref/severe/2013/12Sep2013.pdf

  21. Future things to consider in 0-8 hours • Rainfall verse NOAA-14 data for alerts • Forecasts of Rainfall verse NOAA-14 for alerts • Russ Schumacher sites and examples here • Flash Flood guidance and NOAA-14 data for alerts and heads up at critical thresholds. • Better storm scale ensembles

  22. Stage-IV verse NOAA-14 return periods

  23. 13 Sept

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