1. 1 The Historic Ice Storm of January 26-28, 2009

2. 2 OUTLINE Brief review of the stormBrief review of the storm Review of the environment and forcing (Why was it so bad?)Review of the environment and forcing (Why was it so bad?) Latent heating just about saves the day!Latent heating just about saves the day! Signs of a big event – forecast confidence issuesSigns of a big event – forecast confidence issues

3. 3 The Historic Ice Storm of January 26-28, 2009

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6. 6 UNIQUE IMPACT (THIS TIME IT WAS PERSONAL) The ice storm impacted each and every one of our staff significantly. The ice storm impacted each and every one of our staff significantly. I was without power for 17 days! (I live within a mile of the mall in Paducah, and had no specific trauma to my house.) I was without power for 17 days! (I live within a mile of the mall in Paducah, and had no specific trauma to my house.) Kids in school for a full week without power at the house. Kids in school for a full week without power at the house.

7. 7 January 26-28, 2009 Ice Storm Radar KPAH Reflectivity & METARs 6 PM Monday 12 AM Tuesday

8. 8 January 26-28, 2009 Ice Storm Radar KPAH Reflectivity & METARs 6 AM Tuesday 12 PM Tuesday

9. 9 January 26-28, 2009 Ice Storm Environment 6 PM Friday (23 rd )

10. 10 January 26-28, 2009 Ice Storm Environment 6 PM Monday

11. 11 January 26-28, 2009 Ice Storm Environment 12 AM Tuesday

12. 12 January 26-28, 2009 Ice Storm Environment 6 AM Tuesday

13. 13 January 26-28, 2009 Ice Storm Environment 12 PM Tuesday

14. 14 January 26-28, 2009 Ice Storm Environment 6 PM Tuesday

15. 15 January 26-28, 2009 Ice Storm Environment 6 AM Wednesday

16. 16 January 26-28, 2009 Ice Storm Environment 850-700mb Theta-e Conv. 800mb Wind 6 PM Monday

17. 17 January 26-28, 2009 Ice Storm Environment 850-700mb Theta-e Conv. 800mb Wind 12 AM Tuesday

18. 18 January 26-28, 2009 Ice Storm Environment 850-700mb Theta-e Conv. 800mb Wind 6 AM Tuesday

19. 19 January 26-28, 2009 Ice Storm Environment 850-700mb Theta-e Conv. 800mb Wind 12PM Tuesday

20. 20 January 26-28, 2009 Ice Storm Environment 850-700mb Theta-e Conv. 800mb Wind 6 PM Tuesday

21. 21 January 26-28, 2009 Ice Storm Environment 850-700mb Theta-e Conv. 800mb Wind 12 AM Wednesday

22. 22 January 26-28, 2009 Ice Storm Environment Sounding At KPAH 6 PM Monday

23. 23 January 26-28, 2009 Ice Storm Environment Sounding At KPAH 12 AM Tuesday

24. 24 January 26-28, 2009 Ice Storm Environment Sounding At KPAH 6 AM Tuesday

25. 25 January 26-28, 2009 Ice Storm Environment Sounding At KPAH 12 PM Tuesday

26. 26 January 26-28, 2009 Ice Storm Environment Sounding At KPAH 6 PM Tuesday

27. 27 January 26-28, 2009 Ice Storm Environment Sounding At KPAH 12 AM Wednesday

28. 28 January 26-28, 2009 Ice Storm Environment Classic freezing rain soundings, with a warm layer atop a sub-freezing layer at the surface. Lack of instability  prolonged and persistent light to moderate rain rates  efficient accretion. Latent heating  sudden warming Monday night, with surface temperatures near the freezing mark.

29. 29 January 26-28, 2009 Ice Storm Latent Heat Concerns KPAH & METARs -- 27 JAN 2009 10 AM 12 AM 2 AM

30. 30 January 26-28, 2009 Ice Storm The Perfect Storm Sub-freezing air in place for over 72 hours before storm. Persistent southwest flow aloft with cool northeast flow at the surface. Persistent low-level forcing for lift, with lots of moisture streaming into the region. No instability  lighter rain rates  efficient icing Latent heating continuously offset by cool northeast surface flow. Temperatures staying at or below freezing.

31. 31 January 26-28, 2009 Ice Storm Forecast Confidence 1.Persistent trends in successive runs of a single model. 24+ hours of consistency leads to increased confidence. 2.Personal experience can lead to forecast confidence. “I’ve seen this many times.” – pattern recognition. 3.Clustering of the operational models around a common solution. 4.#3 is a baby step toward Ensemble Forecast Systems.

32. 32 January 26-28, 2009 Ice Storm Forecast Confidence

33. 33 January 26-28, 2009 Ice Storm Environment 6 AM Tuesday

34. 34 January 26-28, 2009 Ice Storm Forecast Confidence  Long Term Noticed this pattern on 4 runs of the GFS over a 2 day period. European model very similar. Recognized the pattern as one that could lead to an unpleasant winter scenario for our area. Aware that these models typically depict major large- scale events very well and very early (7-10days out).

35. 35 January 26-28, 2009 Ice Storm Forecast Confidence  Long Term ILZ094-KYZ005>009-011-211030- MASSAC-MCCRACKEN-GRAVES-LIVINGSTON-MARSHALL-CALLOWAY-LYON- INCLUDING THE CITIES OF...METROPOLIS...PADUCAH...MAYFIELD... SMITHLAND...BENTON...MURRAY...EDDYVILLE 302 PM CST TUE JAN 20 2009.MONDAY THROUGH TUESDAY...MOSTLY CLOUDY WITH A 40 PERCENT CHANCE OF RAIN OR SNOW. HIGHS IN THE UPPER 30S. LOWS IN THE UPPER 20S. HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PADUCAH KY 324 PM CST TUE JAN 20 2009.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A SIGNIFICANT WINTRY PRECIPITATION EVENT IS POSSIBLE DURING THE FIRST HALF OF NEXT WEEK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 125 PM CST TUE JAN 20 2009.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SIGNIFICANT WINTRY PRECIPITATION LOOKING MORE LIKELY AT SOME POINT THE FIRST HALF OF NEXT WEEK.

36. 36 January 26-28, 2009 Ice Storm Signs of a Big Event

37. 37 January 26-28, 2009 Ice Storm Signs of a Big Event

38. 38 January 26-28, 2009 Ice Storm Signs of a Big Event

39. 39 January 26-28, 2009 Ice Storm Forecast Confidence  Short Term Successive model cycles with good clustering of major liquid-equivalent precipitation. The models did not generate enough precipitation, but the inter-model consistency and consistent trend toward the extreme, increased confidence that a major event was about to unfold. The only question at this point, was just how bad would it be?

40. 40 January 26-28, 2009 Ice Storm Short-Range Ensemble Forecasts Consists of 21 individual models or model runs. Consists of models with different numerical guts, or the same models using slightly different observations. Statistics such as the mean and standard deviation can be used to quantify the variability in the forecast. How quickly the model forecasts diverge with time gives a direct measure of how predictable the evolution of the current environment is.

41. 41 January 26-28, 2009 Ice Storm Short-Range Ensemble Forecast Leads directly to probabilistic forecasts of certain events. -- How many members are below freezing at a certain level? --How many members generate a certain amount or type of precipitation? -- How many members have winds above a certain level?

42. 42 January 26-28, 2009 Ice Storm SREF Signs of a Big Event SREF 9 AM Monday Chance of FZRA & 1”/24 hrs QPF Valid 6 PM Tuesday

43. 43 January 26-28, 2009 Ice Storm SREF Signs of a Big Event SREF 9 AM Monday Chance of FZRA & 2”/24 hrs QPF Valid 12 AM Wednesday

44. 44 January 26-28, 2009 Ice Storm SREF Signs of a Big Event SREF 9 AM Monday Chance of T< 0C @ Surface & 850mb Valid 6 AM Tuesday

45. 45 January 26-28, 2009 Ice Storm SREF Signs of a Big Event SREF 9 AM Monday Mean Precipitable Water & Showalter Index Valid 6 AM Tuesday

46. 46 January 26-28, 2009 Ice Storm SREF Signs of a Big Event The GFS and ECMWF nailed the synoptic setting for the event 7 days ahead of time. Model QPFs averaging ~2.5”. Strong signal for 1” and 2” 24 hour QPFs in the SREF. Extreme QPF collocated with high probability of freezing rain in SREF. SREF Mean indicating 250% of normal precipitable water with no instability.

47. 47 Will it ever happen again? Not likely, but….. It could happen this season or next! The Historic Ice Storm of January 26-28, 2009