Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 20, NWS Philadelphia/Mount Holly

May 22, 2014Chester County, Delaware County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 22, 2014, 3:33 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 57 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: May 22, 2014, 3:33 PM EDT (19:33 UTC)
Expired: May 22, 2014, 4:30 PM EDT
In force: 57 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Chester County, PA, Delaware County, PA, Montgomery County, PA

What was reported inside it

Time	Report	Where	Remark
May 22, 4:01 PM EDT	HAIL 1.25	Exton, PA
May 22, 4:13 PM EDT	HAIL 1.5	West Chester, PA
May 22, 4:20 PM EDT	HAIL 1	2 Se Exton, PA	COVERING THE GROUND

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
May 22, 12:39 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.6 hours before the alert went out and 204 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: 291 J/kg
Mixed-layer CIN: -102 J/kg
Mixed-layer LCL: 839 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

457 
WUUS51 KPHI 221933
SVRPHI
PAC029-045-091-222030-
/O.NEW.KPHI.SV.W.0020.140522T1933Z-140522T2030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
333 PM EDT THU MAY 22 2014

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  EASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 430 PM EDT

* AT 330 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM. THE STORM WAS NEAR BIRDSBORO...MOVING
  SOUTHEAST AT 35 MPH. THIS STORM IS CAPABLE OF PRODUCING GOLF BALL
  SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. 

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  CEDARVILLE AND POTTSTOWN AROUND 345 PM EDT...
  PUGHTOWN AROUND 350 PM EDT...
  CHESTER SPRINGS AND ROYERSFORD AROUND 355 PM EDT...
  PHOENIXVILLE AND LIONVILLE AROUND 400 PM EDT...
  MARSHALLTON AROUND 405 PM EDT...
  PAOLI AND VALLEY FORGE AROUND 410 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME ROTATION WITHIN THIS STORM. WHILE
NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A TORNADO IS
SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM ON THE LOWEST
FLOOR.

GOLF BALL SIZE HAIL HAS BEEN OCCURRING WITH THIS STORM, PLEASE MOVE
YOUR CAR INDOORS BEFORE THIS STORM REPORT.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS SEVERE
THUNDERSTORM. WHEN THUNDER ROARS...MOVE INDOORS! 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 EDT
THURSDAY EVENING FOR NORTHERN NEW JERSEY AND EASTERN PENNSYLVANIA. A
SEVERE THUNDERSTORM WATCH ALSO REMAINS IN EFFECT UNTIL 1000 PM EDT
THURSDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY.

&&

LAT...LON 4021 7577 4023 7571 4028 7566 4008 7523
      4006 7526 4003 7524 3985 7565 4013 7588
TIME...MOT...LOC 1933Z 307DEG 29KT 4023 7580

$$

TFG

1 follow-up statement

138 
WWUS51 KPHI 221956
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
356 PM EDT THU MAY 22 2014

PAC029-045-091-222030-
/O.CON.KPHI.SV.W.0020.000000T0000Z-140522T2030Z/
MONTGOMERY PA-DELAWARE PA-CHESTER PA-
356 PM EDT THU MAY 22 2014

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR EASTERN CHESTER...NORTHWESTERN DELAWARE AND SOUTH CENTRAL
MONTGOMERY COUNTIES...

AT 352 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED
NEAR PUGHTOWN...OR 12 MILES NORTH OF WEST CHESTER...MOVING SOUTHEAST
AT 35 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
MARSHALLTON AROUND 405 PM EDT...
PAOLI AND MALVERN AROUND 410 PM EDT...
DEVON-BERWYN AND KING OF PRUSSIA AROUND 415 PM EDT...
NEWTOWN SQUARE AND RADNOR TOWNSHIP AROUND 420 PM EDT...
TROUT LAKE AND BRYN MAWR AROUND 425 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME ROTATION WITHIN THIS STORM. WHILE
NOT IMMEDIATELY LIKELY...A TORNADO MAY DEVELOP. IF A TORNADO IS
SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT
THURSDAY EVENING FOR NORTHERN NEW JERSEY AND EASTERN PENNSYLVANIA. A
SEVERE THUNDERSTORM WATCH ALSO REMAINS IN EFFECT UNTIL 1000 PM EDT
THURSDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY.

&&

LAT...LON 4018 7572 4021 7562 4020 7554 4008 7524
      4007 7524 4006 7526 4003 7524 3985 7565
      4011 7582
TIME...MOT...LOC 1956Z 307DEG 29KT 4012 7561

$$
 
TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
May 22, 3:25 AM EDT	Special Weather Statement	PHI	Lehigh	65 min
May 22, 2:12 PM EDT	Special Weather Statement	PHI	Berks	63 min
May 22, 2:14 PM EDT	Severe Thunderstorm Warning	PHI	Berks	46 min
May 22, 2:29 PM EDT	Special Weather Statement	PHI	Carbon	46 min
May 22, 2:40 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	50 min
May 22, 2:50 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	55 min
May 22, 3:09 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	66 min
May 22, 3:21 PM EDT	Special Weather Statement	PHI	Northampton	24 min
May 22, 3:27 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh, Northampton	33 min
May 22, 3:51 PM EDT	Severe Thunderstorm Warning	PHI	Berks	39 min
May 22, 3:56 PM EDT	Special Weather Statement	PHI	Bucks	34 min
May 22, 4:13 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	62 min
May 22, 4:22 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	38 min
May 22, 4:22 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	53 min
May 22, 4:31 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Delaware, Montgomery	44 min
May 22, 5:23 PM EDT	Special Weather Statement	PHI	Delaware	37 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2014 Every severe thunderstorm warning in 2014

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.