Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 133, NWS Philadelphia/Mount Holly

July 17, 2008Bucks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2008, 5:23 PM EDT for Bucks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 67 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: Jul 17, 2008, 5:23 PM EDT (21:23 UTC)
Expired: Jul 17, 2008, 6:30 PM EDT
In force: 67 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Bucks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 89 km from the middle of the area, began a volume at 21:26 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
Jul 17, 5:43 PM EDT	TSTM WND DMG	5 Se Allentown, PA	TREES AND WIRES DOWN IN UPPER SAUCON TOWNSHIP.

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.4 hours before the alert went out and 137 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: 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 172124
SVRPHI
PAC017-077-095-172230-
/O.NEW.KPHI.SV.W.0133.080717T2123Z-080717T2230Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  SOUTH CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 630 PM EDT

* AT 522 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DIME SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  LEHIGH UNIVERSITY...OR ABOUT NEAR BETHLEHEM...AND MOVING SOUTHEAST
  AT 21 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HELLERTOWN BY 535 PM...
  SPRINGTOWN AND PLEASANT VALLEY BY 545 PM...
  PLEASANT VALLEY BY 550 PM...
  FERNDALE BY 600 PM...
  REVERE BY 605 PM...
  OTTSVILLE AND BEDMINSTER BY 610 PM...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS AND DEADLY CLOUD TO GROUND LIGHTNING. 
PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG 
BUILDING BUT AWAY FROM WINDOWS. CONTINUOUS CLOUD TO GROUND LIGHTNING 
IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY LIGHTNING IS 
ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN HEAR 
THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

LAT...LON 4053 7515 4042 7506 4036 7501 4028 7511
      4059 7549 4068 7539
TIME...MOT...LOC 2123Z 302DEG 18KT 4061 7541

$$

NIERENBERG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 4:09 PM EDT	Excessive Heat Warning	PHI	Delaware, Philadelphia	3 days
Jul 17, 4:31 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	59 min
Jul 17, 4:56 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	64 min
Jul 17, 5:13 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh, Northampton	62 min
Jul 17, 5:14 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	2 hr
Jul 17, 5:55 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery	51 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2008 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.