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Lance Franck Alan Cope NWS Mount Holly, NJ NROW XVII
A Synoptic Climatology of Excessive Heat Events in the Philadelphia Area Lance Franck Alan Cope NWS Mount Holly, NJ NROW XVII
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Background Dataset Parameters:
Philadelphia International Airport (site PHL) May thru Sep ( ) NCEI & XMACIS Statistical Analysis: 90 + Degree Days Heat Indices Dew Points Preliminary Results: Spatial Synoptic Classification Reanalysis Composites (NCEP NARR Daily Average) Backward Trajectory Plots
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Background Primary months for excessive heat are June through August
Third week of July
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Background Primary months for excessive heat are June through August
Second week of July
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Background Corresponding increase in heat-related excess mortality
Jul 4, 1999 – 58 deaths
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Using 90+ Degree Days Limited to consecutive days >= 90 °F
>= 2 days; Typical: <=4 days, <20 degrees, Anomalous: >=6 days, >30 degrees
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“Heat Events Tend to Build”
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“Heat Events Tend to Build”
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Spatial Synoptic Classification (SSC)
Developed by Kalkstein and Greene Each day is classified into a ‘weather type’ mT=Moist Tropical, dM=Dry Moderate, mP=Moist Polar, mM=Moist Moderate, dT= Dry Tropical, dP=Dry Polar
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Spatial Synoptic Classification
mT=Moist Tropical, dT= Dry Tropical
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Spatial Synoptic Classification
mT=Moist Tropical, dT= Dry Tropical
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Anomalous Cases 500 hPa builds rapidly near onset of event
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Anomalous Cases 60 m height anomaly over the northeast US; 250 hPa: 120 m height anomaly just north of Lake Erie
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Anomalous Cases Temperatures in excess of 18 °C; mixing to this level corresponds to surface temps in the low 90s
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Anomalous Cases Temperatures about 4 °C above average.
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Anomalous Cases Surface trough across the I-95 urban corridor
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Anomalous Cases Surface trough also evident in 1000 hPa wind vectors
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Backward Trajectories
Typical Case 6/26 - 6/29/2010 Max T >= 90 °F 4 consecutive days 18 cumulative degrees SSC Type: mT Max Heat Index = 99 Max T = 96 Max Dew Point = 68 2 fatalities
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Backward Trajectories
Anomalous Case 7/4 - 7/11/2010 Max T >= 90 °F 8 consecutive days 46 cumulative degrees SSC Type: dT Max Heat Index = 102 Max T = 103 Max Dew Point = 68 6 fatalities
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Conclusions NCEP NARR Composite Means Anomalous Heat Events
. 500 hPa height anomaly of 60 m just north of Lake Erie (double this anomaly at 200 hPa) 850 hPa temperature anomaly of at least 4 °C Pronounced surface trough in the Interstate 95 corridor, with a subsequent veering of the wind just to the west Spatial Synoptic Classification (SSC) Anomalous Heat Events strongly favor the mT type Typical Heat Events tend toward the mT or dT type Heat Indices Anomalous cases correspond to consecutive days with heat indices >=105 °F in terms of the composite means Future work: Long range pattern recognition of anomalous heat events for lead time purposes (HWO, IDSS, deep core partners), Predictors of specified heat indices (sub-advisory, advisory, and warning criteria), Correlate various meteorological parameters to predict heat related illness and mortality.
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Q & A Lance.Franck@noaa.gov NROW XVII
A Synoptic Climatology of Excessive Heat Events in the Philadelphia Area Q & A NROW XVII
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