Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 63, NWS Philadelphia/Mount Holly

June 12, 2007Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 12, 2007, 2:15 PM EDT for Montgomery County, Philadelphia County, Pennsylvania. It was in force for 30 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jun 12, 2007, 2:15 PM EDT (18:15 UTC)
Expired: Jun 12, 2007, 2:45 PM EDT
In force: 30 min
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

Counties Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 69 km from the middle of the area, began a volume at 18:19 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.

What was reported inside it

Time	Report	Where	Remark
Jun 12, 2:15 PM EDT	HAIL 1	Horsham, PA	QUARTER SIZE HAIL REPORTED IN HORSHAM AND FORT WASHINGTON.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 12, 12:55 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.3 hours before the alert went out and 104 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: 186 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1120 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 34 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS51 KPHI 121815
SVRPHI
PAC091-101-121845-
/O.NEW.KPHI.SV.W.0063.070612T1815Z-070612T1845Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
215 PM EDT TUE JUN 12 2007

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 245 PM EDT

* AT 214 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS NEAR 60 MPH.  THIS STORM WAS LOCATED NEAR
  WILLOW GROVE...OR ABOUT 11 MILES NORTH OF PHILADELPHIA...AND MOVING
  SOUTHWEST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  AMBLER BY 220 PM EDT...
  PLYMOUTH MEETING BY 230 PM EDT...
  CHESTNUT HILL...GERMANTOWN AND NORRISTOWN BY 235 PM EDT...
  BRYN MAWR...ROXBOROUGH AND 6 MILES SOUTHEAST OF KING OF PRUSSIA BY
  245 PM EDT...

LAT...LON 4012 7503 4024 7524 4009 7544 3996 7526
      4001 7516

$$

JRP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 12, 12:56 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	64 min
Jun 12, 1:12 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh	26 min
Jun 12, 1:18 PM EDT	Severe Thunderstorm Warning	PHI	Berks	42 min
Jun 12, 2:00 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Northampton	30 min
Jun 12, 2:25 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	35 min
Jun 12, 2:48 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	42 min
Jun 12, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	40 min
Jun 12, 4:00 PM EDT	Flash Flood Warning	PHI	Montgomery	3 hr
Jun 12, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	37 min
Jun 12, 5:46 PM EDT	Flash Flood Warning	PHI	Bucks	119 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2007 Every severe thunderstorm warning in 2007

Sources

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