warm-season lake-/sea-breeze severe weather in the northeast patrick h. wilson, lance f. bosart, and...
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Warm-SeasonLake-/Sea-Breeze Severe Weatherin the Northeast
Patrick H. Wilson, Lance F. Bosart, and Daniel KeyserDepartment of Earth and Atmospheric Sciences, University at Albany, Albany, NY
Thomas A. WasulaNOAA / National Weather Service, Albany, NY
CSTAR II Grant NA04NWS4680005
Northeast Regional Operational Workshop VIII Presentation
2 November 2006
Research Goals
Investigate thermodynamical and dynamical processes along with physiographic effects
Increase understanding of this phenomenon
Methodology – Part I
Warm-Season: April – October
Domain: OH, PA, MD, DE, NJ, NY, VT, NH, MA, CT, RI, ME
Selected cases from Storm Prediction Center archived storm data 2000-present
Verified from National Climatic Diagnostic Center archived radar data
Methodology – Part II
Obtained NCEP/NARR gridded datasets for each case and plot important weather variables
Collected soundings, radar data, and surface observations
Classified cases into separate categories and conducted case study analyses
Case Classifications
Pure Case: mesoscale forcing primary;
synoptic-scale forcing secondary
Mixed Case: mesoscale forcing and synoptic-
scale forcing working together
Null Case: convection suppressed by
lake-/sea-breeze processes
Case List
Pure Cases
9 August 2001 (Ontario)
6 July 2003 (Erie)
7 August 2005 (Chesapeake)
2 August 2006 (Ontario)
Mixed Cases
9 April 2001 (Erie)
19 June 2002 (Atlantic)
24 July 2003 (Erie and Ontario)
1 August 2005 (Huron and Ontario)
24 April 2006 (Chesapeake)
Null Case11 July 2006 (Atlantic)
1200 UTC 9 August 2001 (Pure Case)
30 35 40 45 50 55 60 65 70
1200 UTC 9 August 2001
14 18 22 26 30 34 38 42 46
1200 UTC 9 August 2001
1200 UTC 9 August 2001http://weather.uwyo.edu/upperair/sounding.html
Note:
Parcel taken from lowest 500 m to determine CAPE
1500 UTC 9 August 2001
-14 -12 -10 -8 -6 -4 -2 0
1800 UTC 9 August 2001
340 345 350 355 360 365 370 375 380
1800 UTC 9 August 2001
-3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0
1700 UTC 9 August 2001
1700 UTC 9 August 2001 Radar Composite
70
60
50
40
30
20
10
1800 UTC 9 August 2001 Radar Composite
70
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50
40
30
20
10
1900 UTC 9 August 2001 Radar Composite
70
60
50
40
30
20
10
2000 UTC 9 August 2001 Radar Composite
70
60
50
40
30
20
10
2100 UTC 9 August 2001 Radar Composite
70
60
50
40
30
20
10
2200 UTC 9 August 2001 Radar Composite
70
60
50
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30
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2300 UTC 9 August 2001 Radar Composite
70
60
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20
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0000 UTC 10 August 2001 Radar Composite
70
60
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30
20
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0100 UTC 10 August 2001 Radar Composite
70
60
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0200 UTC 10 August 2001 Radar Composite
70
60
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30
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10
9 August 2001 Storm Reports
Pure Cases:Preliminary Conclusions
Ridge axis in place at the surface or aloft
Low unidirectional wind shear in low-levels (< 10 m s-1 for 925-700 hPa layer)
T > 30°C, Td > 20°C, CAPE > 1500 J kg-1
Placement and timing signal by θe-ridge axis (θe > 335 K)
Intersections of boundaries enhance convection
Tendency to become squall lines and prefer valleys
Occur most often during hottest months of summer
1200 UTC 19 June 2002 (Mixed Case)
30 35 40 45 50 55 60 65 70
1200 UTC 19 June 2002
14 18 22 26 30 34 38 42 46
1200 UTC 19 June 2002
1200 UTC 19 June 2002http://weather.uwyo.edu/upperair/sounding.html
Note:
Parcel taken from lowest 500 m to determine CAPE
1500 UTC 19 June 2002
-14 -12 -10 -8 -6 -4 -2 0
1800 UTC 19 June 2002
320 325 330 335 340 345 350 355 360
1800 UTC 19 June 2002
1800 UTC 19 June 2002 Radar Composite
70
60
50
40
30
20
10
1900 UTC 19 June 2002 Radar Composite
70
60
50
40
30
20
10
2000 UTC 19 June 2002 Radar Composite
70
60
50
40
30
20
10
19 June 2002 Storm Reports
Mixed Cases:Preliminary Conclusions
Troughs generally in place at the surface or aloft
Typically more wind shear (speed shear and veering winds) in low levels
20°C < T < 30°C, 10°C < Td < 20°C, θe > 320 K
Cyclonic vorticity and cyclonic vorticity advection important
Intersection of boundaries enhance convection
Occur most often during late spring and early autumn
1800 UTC 11 July 2006 (Null Case)
330 335 340 345 350 355 360 365 370
1800 UTC 11 July 2006
1800 UTC 11 July 2006 Radar Composite
70
60
50
40
30
20
10
11 July 2006 Storm Reports
Lake and sea breezes can suppress convection.
1800 UTC 6 July 2003 MODIS Satellitehttp://rapidfire.sci.gsfc.nasa.gov/realtime/
Questions?