Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 134, NWS Philadelphia/Mount Holly

July 17, 20084 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2008, 5:55 PM EDT for 4 counties in Pennsylvania. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 17, 2008, 5:55 PM EDT (21:55 UTC)
Expired
Jul 17, 2008, 6:46 PM EDT
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Berks County, PA, Bucks County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 101 km from the middle of the area, began a volume at 21:56 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.9 hours before the alert went out and 117 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-pSkew-T log-p diagram, Phillips Aaf/Abe, MD at 12:00Z on 2008-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 85 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phillips Aaf/Abe, MD at 12:00Z on 2008-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -34 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
85 J/kg
Mixed-layer CIN
-135 J/kg
Mixed-layer LCL
1547 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-34 m²/s²
0-3 km storm-relative helicity
-48 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 172156
SVRPHI
PAC011-017-077-091-172300-
/O.NEW.KPHI.SV.W.0134.080717T2155Z-080717T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
555 PM EDT THU JUL 17 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL BERKS COUNTY IN EASTERN PENNSYLVANIA...
  SOUTH CENTRAL LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  WEST CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTH CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 700 PM EDT

* AT 552 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM.  THIS STORM WAS LOCATED NEAR ZIONSVILLE...OR
  ABOUT 11 MILES SOUTHWEST OF ALLENTOWN...AND MOVING SOUTHEAST AT 15
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ZIONSVILLE BY 615 PM...
  EAST GREENVILLE BY 625 PM...
  GERYVILLE BY 635 PM...
  QUAKERTOWN BY 700 PM...

LAT...LON 4042 7526 4025 7539 4033 7550 4045 7565
      4051 7559
TIME...MOT...LOC 2155Z 295DEG 10KT 4046 7559

$$

NIERENBERG
1 follow-up statement
000 
WWUS51 KPHI 172246
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
646 PM EDT THU JUL 17 2008

PAC011-017-077-091-172256-
/O.CAN.KPHI.SV.W.0134.000000T0000Z-080717T2300Z/
MONTGOMERY PA-BERKS PA-LEHIGH PA-BUCKS PA-
646 PM EDT THU JUL 17 2008

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL BUCKS...SOUTH
CENTRAL LEHIGH...EAST CENTRAL BERKS AND NORTH CENTRAL MONTGOMERY
COUNTIES IS CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING TO BE ISSUED HAS WEAKENED.
THE SEVERE THUNDERSTORM WARNING IS CANCELLED.

THE SEVERE THUNDERSTORM HAS MOVED AWAY FROM THE AFFECTED AREA.

LAT...LON 4042 7526 4025 7539 4033 7550 4045 7565
      4051 7559
TIME...MOT...LOC 2246Z 295DEG 10KT 4040 7542

$$

NIERENBERG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 4:09 PM EDTExcessive Heat WarningPHIDelaware, Philadelphia3 days
Jul 17, 4:31 PM EDTSevere Thunderstorm WarningPHICarbon59 min
Jul 17, 4:56 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe, Northampton64 min
Jul 17, 5:13 PM EDTSevere Thunderstorm WarningPHILehigh, Northampton62 min
Jul 17, 5:14 PM EDTAreal Flood AdvisoryPHICarbon, Monroe2 hr
Jul 17, 5:23 PM EDTSevere Thunderstorm WarningPHIBucks, Lehigh, Northampton67 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2008Every severe thunderstorm warning in 2008

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.