Warm-Season Lake-/Sea-Breeze
Severe Weather in the Northeast
Patrick H. Wilson, Lance F. Bosart, and Daniel Keyser
Department of Earth and Atmospheric Sciences, University at Albany, Albany, NY
Thomas A. Wasula
NOAA / National Weather Service, Albany, NY
CSTAR-II Grant NA04NWS4680005
M.S. Thesis Seminar Presentation
Department of Earth and Atmospheric Sciences, University at Albany, Albany, NY
1 July 2008
Background and Motivation
 Sea breezes studied well
before 20th century and
accurately described
thermodynamically: Wales
(1914) and Clowes (1917)
 Complexity of sea-breeze
front due to its lobe-and-cleft
structure not realized until
recently: Galvin (2006)
Images from http://weather.cod.edu/sirvatka/seabreeze.html (top)
and Fig. 1 from Galvin (2006) (bottom)
Background and Motivation (continued)
5 m s−1 offshore prevailing geostrophic wind
5 m s−1 onshore prevailing geostrophic wind
 Significant impact of prevailing synoptic-scale flow pattern
on sea breeze evolution and intensity: Estoque (1962)
Fig. 5 (left) and Fig. 9 (right) from Estoque (1962)
Background and Motivation (continued)
 Many examples of sea-breeze convection cases found in
literature: Kingsmill (1995) in FL, Medlin and Croft (1998)
in AL, Bennett et al. (2006) in Great Britain, etc.
 Fewer cases in literature for Northeast exist: Moroz and
Hewson (1966) from MI, Clodman and Chisholm (1994)
and King et al. (2003) from Ontario, and Wolf (2004) in IL
 Lots of research for Great Lakes during winter (lake-effect
snow), but much less research during summer (lake-/seabreeze severe convection)
Research Goals
 Investigate influence of thermodynamic and
dynamical processes, along with physiographic
effects from complex Northeast topography, on
lake-/sea-breeze severe weather
 Increase awareness and understanding of lake-
/sea-breeze severe convection
VT
Methodology
ME
NH
NY
PA
 Warm season: April–October
OH
MD
MA
RI
CT
NJ
DE
 Domain area shown by map
 Selected cases from search of SPC archived storm
data, along with input from NWS meteorologists,
for 2000–2006
 Verified from NCDC archived radar data
Methodology (continued)
 Obtained 32 km-resolution NCEP/NARR gridded datasets
for all cases to perform synoptic-scale analyses
 Acquired 20 km-resolution RUC gridded datasets for three
cases to perform mesoscale analyses
 Collected soundings, radar data, satellite images, water
temperature 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 of similar importance
 Null Case: convection suppressed by
lake-/sea-breeze processes
Case List
Cases chosen for RUC analysis highlighted
 Pure Cases
 Mixed Cases
9 August 2001 (Ontario)
6 July 2003 (Erie)
7 August 2005 (Chesapeake)
2 August 2006 (Ontario)
19 April 2002 (Erie)
19 June 2002 (Atlantic)
24 July 2003 (Erie and Ontario)
1 August 2005 (Huron and Ontario)
30 June 2006 (Erie and Ontario)
23 July 2006 (Erie and Ontario)
 Null Case
11 July 2006 (Atlantic)
Legend
Red: Storm Formation Areas
Pink: Tornado Risk Area
Green: Null Case Area
Arrows: Storm Tracks
Storm Formation Areas and Tracks: All Cases
SPC Verification of Cases
using Convective Outlook
Reports for 2003–2006
 Pure Cases (3)
Slight Risk: 2, General Thunderstorms: 1
 Mixed Cases (4)
Slight Risk: 1, General Thunderstorms: 3
 Null Case (1)
Missed Null Area (Slight Risk)
Pure Case Example
 2 August 2006 (Ontario)
2
4
6
8
10
1200 UTC 2 August 2006: 200 hPa NARR Analysis
Pure
4
8
12
16
20
24
28
1200 UTC 2 August 2006: 500 hPa NARR Analysis
BUF
Pure
1200 UTC 2 August 2006: Surface NARR Analysis
Parcel taken
from lowest
500 m to
determine
CAPE
Pure
1200 UTC 2 August 2006: Sounding
http://weather.uwyo.edu/upperair/sounding.html
Pure
340
345
350
355
360
1600 UTC 2 August 2006: 925 hPa RUC Analysis
Pure
500
1000 1500 2000 2500 3000 3500 4000
1600 UTC 2 August 2006: CAPE and 1000–700 hPa Wind Shear RUC Analysis
Pure
1700 UTC 2 August 2006: Surface Observations
Pure
−3.5
−3.0 −2.5
−2.0
−1.5 −1.0
−0.5
0.0
1800 UTC 2 August 2006: NARR Cross-Section Analysis
70
60
50
40
30
20
10
Pure
1700 UTC 2 August 2006: Radar
70
60
50
40
30
20
10
Pure
1800 UTC 2 August 2006: Radar
70
60
50
40
30
20
10
Pure
1900 UTC 2 August 2006: Radar
70
60
50
40
30
20
10
Pure
2000 UTC 2 August 2006: Radar
70
60
50
40
30
20
10
Pure
2100 UTC 2 August 2006: Radar
70
60
50
40
30
20
10
Pure
2200 UTC 2 August 2006: Radar
70
60
50
40
30
20
10
Pure
2300 UTC 2 August 2006: Radar
Pure
1702 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Pure
1825 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Pure
1902 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Pure
2002 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Pure
2125 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Pure
2202 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Pure
2302 UTC 2 August 2006: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
40 wind and 5 hail reports
Pure
2 August 2006: SPC Storm Reports
http://www.spc.ncep.noaa.gov/climo
Mixed Case Example
 19 June 2002 (Atlantic)
2
4
6
8
10
1200 UTC 19 June 2002: 200 hPa NARR Analysis
Mixed
4
8
12
16
20
24
28
1200 UTC 19 June 2002: 500 hPa NARR Analysis
WAL
Mixed
1200 UTC 19 June 2002: Surface NARR Analysis
Parcel taken
from lowest
500 m to
determine
CAPE
Mixed
1200 UTC 19 June 2002: Sounding
http://weather.uwyo.edu/upperair/sounding.html
Mixed
−10
−8
−6
−4
−2
2
4
6
8
10
1800 UTC 19 June 2002: 500 hPa Vorticity NARR Analysis
Mixed
320
325
330
335
340
345
350
1800 UTC 19 June 2002: 925 hPa RUC Analysis
Mixed
500
1000 1500 2000 2500 3000 3500 4000
1800 UTC 19 June 2002: CAPE and 1000–700 hPa Wind Shear RUC Analysis
Mixed
1800 UTC 19 June 2002: Surface Observations
70
60
50
40
30
20
10
Mixed
1800 UTC 19 June 2002: Radar
70
60
50
40
30
20
10
Mixed
1900 UTC 19 June 2002: Radar
70
60
50
40
30
20
10
Mixed
2000 UTC 19 June 2002: Radar
70
60
50
40
30
20
10
Mixed
2100 UTC 19 June 2002: Radar
Mixed
1732 UTC 19 June 2002: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Mixed
1902 UTC 19 June 2002: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Mixed
2002 UTC 19 June 2002: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
Mixed
2132 UTC 19 June 2002: Visible Satellite
http://dcdbs.ssec.wisc.edu/inventory
3 wind and 27 hail reports
Mixed
19 June 2002: SPC Storm Reports
http://www.spc.ncep.noaa.gov/climo/
Null Case Example
 11 July 2006 (Atlantic)
2
4
6
8
10
1200 UTC 11 July 2006: 200 hPa NARR Analysis
Null
4
8
12
16
20
24
28
1200 UTC 11 July 2006: 500 hPa NARR Analysis
CHH
OKX
Null
1200 UTC 11 July 2006: Surface NARR Analysis
Parcel taken
from lowest
500 m to
determine
CAPE
Null
1200 UTC 11 July 2006: Sounding http://weather.uwyo.edu/upperair/sounding.html
Parcel taken
from lowest
500 m to
determine
CAPE
Null
1200 UTC 11 July 2006: Sounding http://weather.uwyo.edu/upperair/sounding.html
Null
320
325
330
335
340
345
350
1800 UTC 11 July 2006: 925 hPa RUC Analysis
Null
500
1000 1500 2000 2500 3000 3500 4000
1800 UTC 11 July 2006: CAPE and 1000–700 hPa Wind Shear RUC Analysis
Null
1800 UTC 11 July 2006: Surface Observations
Null
−3.5 −3.0 −2.5
−2.0 −1.5 −1.0 −0.5
0.0
1800 UTC 11 July 2006: NARR Cross-Section Analysis
70
60
50
40
30
20
10
Null
1600 UTC 11 July 2006: Radar
70
60
50
40
30
20
10
Null
1700 UTC 11 July 2006: Radar
70
60
50
40
30
20
10
Null
1800 UTC 11 July 2006: Radar
70
60
50
40
30
20
10
Null
1900 UTC 11 July 2006: Radar
70
60
50
40
30
20
10
Null
2000 UTC 11 July 2006: Radar
70
60
50
40
30
20
10
Null
2100 UTC 11 July 2006: Radar
21 wind and 32 hail reports
Null
11 July 2006: SPC Storm Reports
http://www.spc.ncep.noaa.gov/climo
Null
24-hour Quantitative Precipitation Estimates ending at 1200 UTC 12 July 2006
http://www.hpc.ncep.noaa.gov/npvu/archive/rfc.shtml
Pure Case Conclusions
 No synoptic-scale disturbance present, 1000–500 hPa thickness
≥570 dam, land/water temperature difference ≥5°C in afternoon
 T ≥30°C and Td ≥20°C in afternoon, CAPE ≥1500 J kg−1 and CIN
≥−125 J kg−1 from 1200 UTC soundings
 Placement and timing signal given by 925 hPa θe-ridge axis with
θe ≥335 K, and tendency to sometimes become squall lines
 1000–700 hPa onshore wind shear ≥15 kt for organized storms,
and boundary intersections can further enhance convection
 Occur most often during hottest months of summer with a moist
atmosphere (PW ≥40mm)
Mixed Case Conclusions
 Synoptic-scale disturbance present, 1000–500 hPa thickness
≥555 dam, land/water temperature difference ≥5°C in afternoon
 T ≥20°C and Td ≥10°C in afternoon, CIN ≥−100 J kg−1 from 1200
UTC soundings
 Placement and timing signal given by 925 hPa θe-ridge axis
(320 K ≤ θe ≤ 350 K) and presence of cyclonic vorticity advection
 1000–700 hPa onshore wind shear ≥20 kt for organized storms,
and boundary intersections can further enhance convection
 Occur most often during late spring, early autumn, and cooler
portions of summer (PW ≥25mm)
Null Case Conclusions
 Preexisting convection interacts with a lake or sea breeze and
crosses over into the marine air
 Convection suppressed with the boundary layer too stable to
maintain updrafts (less CAPE, more CIN)
 Significant θe-difference (≥10°C) between the contrasting air
masses
 Conditions for severe convection can be highly favorable aloft in
the null region due to synoptic-scale patterns
 Key to these cases is boundary layer characteristics
Summary Flowchart
Is PW ≥25mm at 1200 UTC,
and will CAPE be
≥500 J kg−1 by 1500 UTC?
Yes
No
Will the water be ≥5°C
cooler than the air over
land after 1500 UTC?
Severe weather
highly unlikely
No
Yes
Will there be onshore surface
flow ≥5 kt by 1500 UTC
to persist the rest of the day?
Yes
Yes
Mixed case likely
No
Lake-/sea-breeze-induced
severe weather unlikely
Is there a
synoptic-scale
disturbance present?
No
Pure case likely
Null Case Questions
 Is there a persistent lake or sea breeze present
(synoptically and/or mesoscale driven)?
 Is large CIN (≤−125 J kg−1) present to promote a deep
and possibly impenetrable cap?
 Is there a significant departure in temperature and θe
between air masses (lake-/sea-breeze air vs. nonlake-/sea-breeze air)?
Thank you to all of my family and friends and the faculty,
staff, and graduate students of the department for all your
help, education, and moral support!
Eating Establishment in Park City, UT on 26 June 2007 during 22nd WAF conference
Questions or comments?
pwilson@atmos.albany.edu
All research material available online at:
http://www.atmos.albany.edu/student/pwilson/