Alert archive / Pennsylvania / Excessive Heat Watches in 2019

Excessive Heat Watch 3, NWS Philadelphia/Mount Holly

August 17, 20194 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this excessive heat watch at Aug 17, 2019, 3:31 PM EDT for 4 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued: Aug 17, 2019, 3:31 PM EDT (19:31 UTC)
Expired: Aug 18, 2019, 3:32 AM EDT
In force: 12 hr
Issued by: NWS Philadelphia/Mount Holly

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Mercer County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 66 km from the middle of the area, began a volume at 19:33 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 7.5 hours before the alert went out and 220 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 898 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 462 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this excessive heat watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before this excessive heat watch went out at Aug 17, 11:50 AM EDT, 3 hours 41 minutes earlier.

Area forecast discussion, Aug 17, 11:50 AM EDT, 3 hours 41 minutes before

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Hazardous weather outlook, Aug 17, 3:36 AM EDT, 11 hours 55 minutes before

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In the hours before

Special weather statement, Aug 17, 1:08 PM EDT, 2 hours 23 minutes before

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Special weather statement, Aug 17, 1:33 PM EDT, 1 hour 58 minutes before

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The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 16, 11:32 PM EDT	Areal Flood Advisory	PHI	Sussex, Warren	118 min
Aug 17, 1:08 PM EDT	Special Weather Statement	PHI	Lebanon	37 min
Aug 17, 1:33 PM EDT	Special Weather Statement	PHI	Berks	42 min

Nearby

Excessive Heat Watches in Pennsylvania, 2019 Excessive Heat Watches in New Jersey, 2019 Excessive Heat Watches in Delaware, 2019 Every excessive heat watch in 2019

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.