Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 167, NWS Philadelphia/Mount Holly

July 27, 2008Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 27, 2008, 12:07 PM EDT for Chester County, Pennsylvania. It was in force for 53 min. 2 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: Jul 27, 2008, 12:07 PM EDT (16:07 UTC)
Expired: Jul 27, 2008, 1:00 PM EDT
In force: 53 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 127 km from the middle of the area, began a volume at 16:09 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 27, 12:50 PM EDT	HAIL 1	8 Se Quarryville, PA	HAIL FLATTENED CORN ON FARM NEAR KIRKWOOD
Jul 27, 12:55 PM EDT	HAIL 0.75	6 Se Honey Brook, PA	PENNY SIZE HAIL REPORTED ABOUT 6 MILES SOUTHEAST OF HONEY BROOK. SPOTTER REPORT RELAYED BY WFO STATE COLLEGE.

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
Jul 27, 11:26 AM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 4.1 hours before the alert went out and 166 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: 1356 J/kg
Mixed-layer CIN: -70 J/kg
Mixed-layer LCL: 1062 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 63 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 271608
SVRPHI
PAC029-271700-
/O.NEW.KPHI.SV.W.0167.080727T1607Z-080727T1700Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1207 PM EDT SUN JUL 27 2008

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 100 PM EDT

* AT 1202 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  MOUNT VERNON...OR ABOUT 18 MILES SOUTHEAST OF LANCASTER...AND
  MOVING EAST AT 19 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HOMEVILLE BY 1215 PM...
  COCHRANVILLE BY 1225 PM...
  PARKESBURG AND 7 MILES NORTH OF WEST GROVE BY 1235 PM...
  COATESVILLE BY 1250 PM...
  7 MILES NORTH OF KENNETT SQUARE BY 1255 PM...
  MARSHALLTON...DOWNINGTOWN...7 MILES WEST OF WEST CHESTER AND 9
  MILES SOUTHWEST OF LIONVILLE BY 100 PM...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT 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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

LAT...LON 3983 7604 3985 7604 3988 7600 3992 7602
      3994 7600 3996 7600 4003 7596 4012 7556
      4005 7543 3974 7580 3973 7611
TIME...MOT...LOC 1607Z 249DEG 16KT 3986 7603

$$

GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 11:50 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	70 min
Jul 27, 12:19 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Lehigh, Montgomery	56 min
Jul 27, 12:25 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	3 hr
Jul 27, 12:38 PM EDT	Severe Thunderstorm Warning	PHI	Chester	67 min
Jul 27, 12:50 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Montgomery	3 hr
Jul 27, 12:57 PM EDT	Severe Thunderstorm Warning	PHI	Chester	63 min
Jul 27, 1:00 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	60 min
Jul 27, 1:34 PM EDT	Flash Flood Warning	PHI	Chester	3 hr
Jul 27, 1:44 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	61 min
Jul 27, 2:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	64 min
Jul 27, 2:14 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Philadelphia	61 min
Jul 27, 2:17 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	58 min
Jul 27, 2:30 PM EDT	Areal Flood Advisory	PHI	Bucks	2 hr
Jul 27, 5:04 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester	56 min
Jul 27, 6:44 PM EDT	Areal Flood Advisory	PHI	Chester	72 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.