Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 208, NWS Philadelphia/Mount Holly

August 17, 2007Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 17, 2007, 4:51 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 43 min. 3 reports 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: Aug 17, 2007, 4:51 PM EDT (20:51 UTC)
Expired: Aug 17, 2007, 5:34 PM EDT
In force: 43 min
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

Counties Lehigh County, PA, Northampton County, PA

What was reported inside it

Time	Report	Where	Remark
Aug 17, 5:06 PM EDT	TSTM WND DMG	Coplay, PA	TREES REPORTED ON ROADWAYS IN WHITEHALL TOWNSHIP.
Aug 17, 5:10 PM EDT	HAIL 0.75	Nazareth, PA	PENNY SIZED HAIL REPORTED AT THE 911 CALL CENTER.
Aug 17, 5:20 PM EDT	HAIL 1.25	Bethlehem, PA	HAIL 1.25 INCHES IN DIAMETER WAS REPORTED IN BETHLEHEM.

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
Aug 17, 1:37 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 8.9 hours before the alert went out and 230 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: 120 J/kg
Mixed-layer CIN: -267 J/kg
Mixed-layer LCL: 1465 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: -31 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.4

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 172051
SVRPHI
PAC077-095-172145-
/O.NEW.KPHI.SV.W.0208.070817T2051Z-070817T2145Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
451 PM EDT FRI AUG 17 2007

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF ALLENTOWN...
  SOUTHWESTERN NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF BETHLEHEM...

* UNTIL 545 PM EDT

* AT 449 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL.  THIS
  STORM WAS LOCATED NEAR EMERALD...OR ABOUT 15 MILES NORTHWEST OF
  ALLENTOWN...AND MOVING EAST AT 50 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  SCHNECKSVILLE...NEFFS...BERLINSVILLE...DANIELSVILLE...BEERSVILLE...
  NORTHAMPTON...BATH...STEUBEN...LEHIGH UNIVERSITY AND NAZARETH

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT FRIDAY
EVENING FOR NORTHERN DELAWARE AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

LAT...LON 4074 7577 4078 7568 4078 7563 4080 7556
      4081 7550 4082 7548 4076 7528 4054 7542
      4071 7578
TIME...MOT...LOC 2051Z 289DEG 50KT 4076 7562

$$

JJM

1 follow-up statement

000 
WWUS51 KPHI 172134
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
533 PM EDT FRI AUG 17 2007

PAC077-095-172143-
/O.CAN.KPHI.SV.W.0208.000000T0000Z-070817T2145Z/
LEHIGH PA-NORTHAMPTON PA-
533 PM EDT FRI AUG 17 2007

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN NORTHAMPTON AND
NORTHERN LEHIGH COUNTIES IS CANCELLED...

THE THUNDERSTORMS HAVE MOVED JUST TO THE EAST AND OUT OF THE WARNED 
AREA.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT FRIDAY
EVENING FOR NORTHERN DELAWARE AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

LAT...LON 4074 7577 4078 7568 4078 7563 4080 7556
      4081 7550 4082 7548 4076 7528 4054 7542
      4071 7578
TIME...MOT...LOC 2133Z 289DEG 50KT 4057 7489

$$

JRP

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 1:48 PM EDT	Severe Thunderstorm Warning	PHI	Chester	72 min
Aug 17, 2:07 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	68 min
Aug 17, 2:14 PM EDT	Tornado Warning	PHI	Chester	46 min
Aug 17, 2:19 PM EDT	Tornado Warning	PHI	Carbon	26 min
Aug 17, 2:20 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	70 min
Aug 17, 2:36 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	54 min
Aug 17, 2:41 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	79 min
Aug 17, 2:43 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	62 min
Aug 17, 2:45 PM EDT	Tornado Warning	PHI	Carbon, Northampton	45 min
Aug 17, 2:54 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh	66 min
Aug 17, 4:42 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	19 min
Aug 17, 4:45 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	60 min
Aug 17, 5:17 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	58 min
Aug 17, 7:56 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	19 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.