Lake Ontario Unleashed:   A Recap of the Historic February 2-12 Lake Effect Snow Event Matt Lanza, Meteorologist ,  WKTV- ...
Overview <ul><li>Brief Primer on Lake Effect (LES) and Lake Ontario Geography </li></ul><ul><li>The Winter of 2006-2007 le...
What is Lake Effect Snow? <ul><li>Common convention: Cold air moving over the relatively warmer lake waters. </li></ul><ul...
What is Lake Effect Snow? <ul><li>Air continues to rise, cool, and can eventually condense enough to produce precipitation...
What is Lake Effect Snow? <ul><li>So every time there’s an Arctic air mass, we get dumped on with LES, right? Wrong! </li>...
What is Lake Effect Snow? <ul><li>A few specifics: - 850 mb temps should be 13°C cooler    than the lake temperature (27-2...
What is Lake Effect Snow? <ul><li>A few specifics: - Fetch over the lake should be over as    much of it as possible! </li...
What is Lake Effect Snow? <ul><li>A few specifics: - Upstream connections: Winds    transporting moisture from Lake Superi...
Geography Lesson
Geography Lesson
Winter 06-07: Tale of Two Seasons <ul><li>November 1-January 15 at UCA/RME: Temperature:  +9.0°  (38.0°) Snowfall:  -31.1”...
Winter 06-07: Tale of Two Seasons <ul><li>Above normal air temperatures helped keep lake temperatures well above normal as...
Synoptic Setup for LES Event <ul><li>With region primed, all it took was a seasonably cool air mass to kick start the lake...
Synoptic Setup for LES Event Alberta Clipper swings   through Synoptic snows wind down at 00Z.
00Z February 3 rd  (Friday, 7 PM) Alberta Clipper dragged a cold front through Great Lakes Anomalously cold 850 mb tempera...
12Z February 3 rd  (Saturday, 7 AM) Deepening Polar air mass over Lakes, as 850 mb temps fall to -18°C over Lake Ontario. ...
12Z February 4 th  (Sunday, 7 AM) Shortwave trough passed through Deepening 850 mb cold, as temps fall to  -23°C Synoptic ...
00Z February 5 th  (Sunday, 7 PM) Another weak shortwave crossed over Lakes Winds shifted aloft from WSW to more Westerly ...
12Z February 5 th  (Monday, 7 AM) Final major shift occurred, shifting winds into broad west and west-northwest direction;...
Synoptic Setup for LES Event <ul><li>Over the next 7 days, shortwave troughs acted to move the band north and south at abo...
February 2
February 3
February 4
February 5
February 6
February 7
February 8
February 9
February 10
February 11
February 12
 
Results… Point Rock, NY, February 6
Results… Point Rock, NY, February 6
Results… Westernville, NY, February 6
Results… Westernville, NY, February 6
Results… Lake Delta, NY, February 6 Lawn   Chairs!
Results… Lake Delta, NY, February 6
Results… Westdale, NY, February 7
Results… Turin, NY, February 10
Results… Mexico, NY
Results… Oswego, NY
Results… Oswego, NY
Results… Mexico, NY
Results… Camden, NY
Results… Camden, NY
Results… Williamstown, NY
Results… Viewer in Deerfield, NY
Stats… <ul><li>Top 5 Snow Totals (2/2 – 2/12): 1.) Redfield: 141.0” * 2.) Parish: 121.0” 3.) North Osceola: 106.0” 3.) Mex...
Official Snowfall Map
Matt’s Unofficial Snowfall Map
What We Learned <ul><li>Computer Models, even the finer resolution mesoscale models are great, but they can’t pick up ever...
What We Learned <ul><li>The models were good with QPF in the sense that it was obvious something big was going to occur. <...
What We Learned <ul><li>Not unusual to have LES mega-events off the lakes. </li></ul><ul><li>Very unusual to have 10 day m...
What We Learned <ul><li>Bottom line: Snowfall forecasts beyond the 18-24 hour range were extremely difficult due to band m...
For Future Events… <ul><li>More must be done to encourage snow spotting in Upstate New York, specifically in the Tug Hill ...
For Future Events… <ul><li>Economic dependence on snow in Upstate New York should encourage more SKYWARN participation. </...
For Future Events… <ul><li>Forecasters must use computer models as a rough guide, not as a crutch. </li></ul><ul><li>A 2.0...
Entire February LES Study Online <ul><li>http://www.wktv.com/weather/6812412.html </li></ul><ul><li>Features day by day an...
Thank You! Questions or comments: mlanza@wktv.com
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Lake Ontario Unleashed: An Analysis of a February 2007 Lake Effect Event

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Detailed discussion of the February 2-12, 2007 massive lake effect event off the east end of Lake Ontario, featuring details, analysis, photos and more.

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Lake Ontario Unleashed: An Analysis of a February 2007 Lake Effect Event

  1. 1. Lake Ontario Unleashed: A Recap of the Historic February 2-12 Lake Effect Snow Event Matt Lanza, Meteorologist , WKTV- Utica, NY Eastern U.S. Weather Conference III: June 23, 2007
  2. 2. Overview <ul><li>Brief Primer on Lake Effect (LES) and Lake Ontario Geography </li></ul><ul><li>The Winter of 2006-2007 leading up to the event </li></ul><ul><li>Synoptic (Large Scale) setup for the event </li></ul><ul><li>Eleven Days of Snow: Highlights/Photos from long-duration event </li></ul><ul><li>Statistics from the event </li></ul><ul><li>Suggestions for improving handling of future events </li></ul>
  3. 3. What is Lake Effect Snow? <ul><li>Common convention: Cold air moving over the relatively warmer lake waters. </li></ul><ul><li>Cold air crossing the lakes is dry, and evaporation occurs near the surface. </li></ul><ul><li>“ Warm,” moist air near the surface of the lakes rises, cools slightly and forms into cumulus clouds. </li></ul><ul><li>Depending on intensity of the air mass, significant instability can enhance the process. </li></ul>
  4. 4. What is Lake Effect Snow? <ul><li>Air continues to rise, cool, and can eventually condense enough to produce precipitation. </li></ul><ul><li>Precip can fall as either rain or snow </li></ul><ul><li>Intensity is enhanced by frictional convergence at the lake shore, as well as upsloping (forcing air upward due to terrain). </li></ul>
  5. 5. What is Lake Effect Snow? <ul><li>So every time there’s an Arctic air mass, we get dumped on with LES, right? Wrong! </li></ul><ul><li>Factors that must be examined include: - Degree of instability - Fetch - Wind Shear (speed/vertical) - Upstream contributions - Ice cover? - Synoptic contributions? - Geography </li></ul>
  6. 6. What is Lake Effect Snow? <ul><li>A few specifics: - 850 mb temps should be 13°C cooler than the lake temperature (27-28° at 700 mb or 50° at 500 mb for major events). - Vertical wind shear from the surface to 700 mb level should be less than 30°. </li></ul><ul><li>- Speed shear not too significant </li></ul><ul><li>- Lake induced CAPEs usually about 300 J/kg </li></ul>
  7. 7. What is Lake Effect Snow? <ul><li>A few specifics: - Fetch over the lake should be over as much of it as possible! </li></ul>
  8. 8. What is Lake Effect Snow? <ul><li>A few specifics: - Upstream connections: Winds transporting moisture from Lake Superior to Lake Huron or Lake Huron/Georgian Bay to Lake Ontario. - Synoptic setup: Cyclonic flow and positive vorticity advection often acts to enhance snowfall. - High inversion level helps as well. </li></ul>
  9. 9. Geography Lesson
  10. 10. Geography Lesson
  11. 11. Winter 06-07: Tale of Two Seasons <ul><li>November 1-January 15 at UCA/RME: Temperature: +9.0° (38.0°) Snowfall: -31.1” (15.9”) </li></ul><ul><li>January 16-March 31 at UCA/RME Temperature: -4.1° (21.4°) Snowfall: +60.8” (108.0”) </li></ul>
  12. 12. Winter 06-07: Tale of Two Seasons <ul><li>Above normal air temperatures helped keep lake temperatures well above normal as well. </li></ul><ul><li>With limited LES through late January (biggest events were the Buffalo snows of October and early November snows off Ontario), lake snowbelts were primed to get hammered. </li></ul>
  13. 13. Synoptic Setup for LES Event <ul><li>With region primed, all it took was a seasonably cool air mass to kick start the lake. </li></ul><ul><li>January 29 th saw that occur as 20-40” fell near the lakeshore north of Syracuse. </li></ul><ul><li>What happens when you get an Unseasonably cold air mass? </li></ul>
  14. 14. Synoptic Setup for LES Event Alberta Clipper swings through Synoptic snows wind down at 00Z.
  15. 15. 00Z February 3 rd (Friday, 7 PM) Alberta Clipper dragged a cold front through Great Lakes Anomalously cold 850 mb temperatures driven south and eastward with Polar Vortex; -10°C was threshold for LES Deep synoptic moisture was in place
  16. 16. 12Z February 3 rd (Saturday, 7 AM) Deepening Polar air mass over Lakes, as 850 mb temps fall to -18°C over Lake Ontario. Deep synoptic moisture remained in place Secondary push of Polar air seen with low pressure over U.P. of Michigan
  17. 17. 12Z February 4 th (Sunday, 7 AM) Shortwave trough passed through Deepening 850 mb cold, as temps fall to -23°C Synoptic moisture in place across all the Lakes Core of upper level cold laid out near Lakes
  18. 18. 00Z February 5 th (Sunday, 7 PM) Another weak shortwave crossed over Lakes Winds shifted aloft from WSW to more Westerly direction 850 mb cold continued to deepen with temperature range of -28°C to -24°C across the Lakes Synoptic moisture continued to reload across the Lakes
  19. 19. 12Z February 5 th (Monday, 7 AM) Final major shift occurred, shifting winds into broad west and west-northwest direction; 850 mb cold continued to hold Synoptic moisture continued to remain deep and in tact
  20. 20. Synoptic Setup for LES Event <ul><li>Over the next 7 days, shortwave troughs acted to move the band north and south at about 12-18 hour intervals. </li></ul><ul><li>Wind flow on average stayed between 225 degrees and 325 degrees. </li></ul><ul><li>The following are 24 hour radar loops from Weather Underground of the entire event. </li></ul>
  21. 21. February 2
  22. 22. February 3
  23. 23. February 4
  24. 24. February 5
  25. 25. February 6
  26. 26. February 7
  27. 27. February 8
  28. 28. February 9
  29. 29. February 10
  30. 30. February 11
  31. 31. February 12
  32. 33. Results… Point Rock, NY, February 6
  33. 34. Results… Point Rock, NY, February 6
  34. 35. Results… Westernville, NY, February 6
  35. 36. Results… Westernville, NY, February 6
  36. 37. Results… Lake Delta, NY, February 6 Lawn Chairs!
  37. 38. Results… Lake Delta, NY, February 6
  38. 39. Results… Westdale, NY, February 7
  39. 40. Results… Turin, NY, February 10
  40. 41. Results… Mexico, NY
  41. 42. Results… Oswego, NY
  42. 43. Results… Oswego, NY
  43. 44. Results… Mexico, NY
  44. 45. Results… Camden, NY
  45. 46. Results… Camden, NY
  46. 47. Results… Williamstown, NY
  47. 48. Results… Viewer in Deerfield, NY
  48. 49. Stats… <ul><li>Top 5 Snow Totals (2/2 – 2/12): 1.) Redfield: 141.0” * 2.) Parish: 121.0” 3.) North Osceola: 106.0” 3.) Mexico: 106.0” 5.) Westdale: 100.0” * Would have set a record for most snow from a single lake effect event, but due to the length of time it lasted, the NWS stated it would be impossible to consider it a record. </li></ul>
  49. 50. Official Snowfall Map
  50. 51. Matt’s Unofficial Snowfall Map
  51. 52. What We Learned <ul><li>Computer Models, even the finer resolution mesoscale models are great, but they can’t pick up every single disturbance that will come through and shift winds. </li></ul><ul><li>Example of 36 hour QPF that was 20 miles too far south. </li></ul>NWS Buffalo WRF Model Saturday night through Sunday afternoon
  52. 53. What We Learned <ul><li>The models were good with QPF in the sense that it was obvious something big was going to occur. </li></ul><ul><li>The models were off on placement. </li></ul><ul><li>If you exclusively used surface and upper air analysis maps to do short-fuse 24-48 hour forecasts, your accuracy would have likely been better than by using the models. </li></ul>
  53. 54. What We Learned <ul><li>Not unusual to have LES mega-events off the lakes. </li></ul><ul><li>Very unusual to have 10 day mega-events with such a large spatial expanse receiving 60-80”+ of snow. </li></ul><ul><li>Upper lakes connections (Huron/G-Bay) helped deliver 6-8” per hour snowfall rates in spots. </li></ul><ul><li>Not too difficult to say when upper lakes may come into play, but very difficult to determine how prolific snowfall rates will be. </li></ul>
  54. 55. What We Learned <ul><li>Bottom line: Snowfall forecasts beyond the 18-24 hour range were extremely difficult due to band movement as well as model difficulties. </li></ul><ul><li>Snow reports in strategic locations difficult due to sparse population. </li></ul>
  55. 56. For Future Events… <ul><li>More must be done to encourage snow spotting in Upstate New York, specifically in the Tug Hill Region. </li></ul><ul><li>Not impossible to do, as NWS Albany claims that 1% of population of Hamilton County (Adirondacks) is SKYWARN certified. </li></ul><ul><li>Reports need to be received in a more timely manner as well. </li></ul>
  56. 57. For Future Events… <ul><li>Economic dependence on snow in Upstate New York should encourage more SKYWARN participation. </li></ul><ul><li>Better reports will lead to better forecasts and publicity of snowfall totals, which could lead to more tourism. </li></ul><ul><li>Percentage of economy dependent on winter tourism is far greater than almost anywhere else in the East. </li></ul>
  57. 58. For Future Events… <ul><li>Forecasters must use computer models as a rough guide, not as a crutch. </li></ul><ul><li>A 2.00” liquid QPF bullseye on Montague might not mean Montague gets 40” of snow, but someone in the Lakes could. </li></ul><ul><li>They will tell you that it’s favorable for major LES, but they cannot give you specifics. </li></ul><ul><li>Watch surface and upper air analysis very closely. </li></ul>
  58. 59. Entire February LES Study Online <ul><li>http://www.wktv.com/weather/6812412.html </li></ul><ul><li>Features day by day analysis, every 3 hour Montague radar images, numerous satellite images and other fun things. </li></ul><ul><li>Mandatory viewing for snow junkies! </li></ul>
  59. 60. Thank You! Questions or comments: mlanza@wktv.com

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