Warm Season Thunderstorm Patterns Over the New Jersey Area
Al Cope Paul CroftNational Weather Service Kean University
Mount Holly, NJ Union, NJ
Purpose/Intent Determine Convective Initiation Identify Patterns & Coverage Movement, Intensity, Duration
Thunderstorm Characteristics: Spatial – Linear, Isolated, Clustered, Scattered, Widespread &
where will they occur?
Temporal – When will they occur? Continuous in time? How long will they last?
Severity – Pulse, Squall, Organized & type of severe weather or hazard (i.e. tornado, high wind, large hail, heavy rain, lightning)
Topography and Land UseSurface Characteristics
0 20 40 60 8010Kilometers
Surface Character
Null
Open Water
Residential
Commercial
Industrial
Utilities
Barren
Deciduous
Evergreen
Mix Forest
Cropland
Horticulture
Streams, Rivers
Bays, Estuaries0 20 40 60 8010km
KTTN
KPHL
KMPO
KLGA
KJFK
KILG
KEWR
KNYC
KACY
KABE
´0 25 50 75 10012.5
Kilometers
Elevation
Elevation (m)
Value
-85 - 0
0 - 52
52 - 99
99 - 145
145 - 192
192 - 245
245 - 304
304 - 364
364 - 423
423 - 488
488 - 561
561 - 728
Topography
Data Collection – 2006 & 2007
Summer data collection at Kean U. and NWS Mount Holly, NJ (Kean students and student volunteers at NWS PHI)
Daily data collection and archive of radar every three hours (more when warranted) – mapping of cells/features as well as time and motion
Maps: Upper Air, Surface Analyses Numeric Values: Skew-T, Satellite-derived, others Other Features: Sea breeze, mountain-valley circulations, physiographic features WRF Modeling (http://hurri.kean.edu/~nwpmodel) – in-house mesoscale model (see
expected evolution from dynamic model perspective)
“Event” activity initiates after 12 UTC “Contaminate” activity is ongoing and/or moving into region before 15 UTC “Non-Event” is null case, no activity observed between 12 and 00 UTC
Methods & Products
Initiate Analysis for determination of spatial and temporal distributional characteristics and behaviors of convective initiates and the subsequent and total activity across the study area
Statistical Analysis for determination of convective features and to assess relationship to synoptic weather patterns, mesoscale circulations, and physiographic features
Event/Contaminated N NE E SE S SW W NWJune 0,0 0,0 0,0 0,0 0,1 4,1 0,1 0,1July 0,0 0,0 0,0 0,0 0,0 1,1 6,2 0,0
August 0,0 0,0 0,0 0,0 0,0 0,0 2,2 0,0Total 0,1 5,2 8,5 0,1
Base State Flow at 500mbEvent/Contaminated N NE E SE S SW W NW
June 2,0 0,0 0,0 0,0 0,1 1,1 4,1 0,0July 0,0 0,0 0,0 0,0 0,0 7,4 2,0 0,1
August 0,0 0,0 0,0 0,0 0,0 1,0 6,3 0,1Total 2,0 0,0 0,0 0,0 0,1 9,5 12,4 0,2
Base State Flow at 500mb
2006June July August Total
Event 4 7 2 13Contaminated 4 3 2 9
Total 8 10 4 22
Frequency Distribution 2007June July August Total
Event 9 10 7 26Contaminated 4 5 4 13
Total 13 15 11 39
Frequency Distribution
EVENTS - 500 mb West Flow
EVENTS - 500 mb SW Flow
Contaminates – 500mb W & SW Flow
West Flow at 500 mb Southwest Flow at 500 mb
Initial Results…
Convective Contaminates
Contaminates do not preclude further activity with only one exception
Contaminates more ‘focused’ cell areas with W-500mb flow
S/SW flow contaminates mostly found in southern NJ & coastal regions
Seasonal progression appears to reduce the “source region” of initiation in NE PA and NW NJ
Total activity highly variable
Convective Events
Initiates (W) similar location of origin to contaminates but they mostly developed outside NJ; most total activity isolated clusters or cells & less “focused” in comparison to contaminates
June progressing to August shows just over half initiates have origin in southern half of study region versus very little in those locations during the early summer
Initiates (SW) were found across study region and were not constrained to southern NJ (as were the contaminates)
Activity highly variable, but limited, in time-placement-coverage versus contaminates that tended to cluster
Initiates for Events
•Most initiates in NE-PA/NW-NJ
•Trend toward S-NJ later in Summer
Role of Topography?
Sea-breeze Influences
•Favored in July and August
•500mb flow from W and SW
•Often weak/short-lived (not always)
•Generally occurred well inland
Continuing Work…
Collect and analyze data from previous years
Look at severity, lightning, flooding, etc. based on different regimes
Investigate role of sea breeze, topography, other meso-scale factors…relate to large-scale
Verify NWS grid/tabular forecasts vs. observed T-storm activity (Pop, QPF, Weather, Sky…)
Develop conceptual models and and forecast guidelines for initial activity and evolution
Fin…Ende…Finis…The End
AcknowledgementsKean Department of Geology & MeteorologyFaculty & Staff, Students and Majors, Alumni
NWS Mount Holly Staff and Student VolunteersKean University Meteorology Program
Office of Research & Sponsored ProgramsCenter for Professional Development
This report was prepared by Kean University and the National Weather Service under a sub-award with the University Corporation for Atmospheric Research (UCAR) under Cooperative Agreement with the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce (DOC).