Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 9, NWS Philadelphia/Mount Holly

May 24, 2012Mercer County, New Jersey; Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 24, 2012, 2:08 PM EDT for Mercer County, New Jersey; Bucks County, Montgomery County, Pennsylvania. It was in force for 52 min. 5 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 24, 2012, 2:08 PM EDT (18:08 UTC)
Expired: May 24, 2012, 3:00 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Mercer County, NJ, Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 50 km from the middle of the area, began a volume at 18:07 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
May 24, 2:12 PM EDT	HAIL 0.25	Langhorne, PA
May 24, 2:13 PM EDT	TSTM WND GST 52	Trenton, NJ
May 24, 2:16 PM EDT	HAIL 0.5	Newtown, PA
May 24, 2:20 PM EDT	HAIL 0.25	Trenton, NJ
May 24, 2:29 PM EDT	TSTM WND DMG	Jamison, PA	LARGE TREE LIMBS DOWN

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, 6.1 hours before the alert went out and 128 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: 302 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 499 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: -11 m²/s²
0-3 km storm-relative helicity: 6 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.

823 
WUUS51 KPHI 241808
SVRPHI
NJC021-PAC017-091-241900-
/O.NEW.KPHI.SV.W.0009.120524T1808Z-120524T1900Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
208 PM EDT THU MAY 24 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN MERCER COUNTY IN CENTRAL NEW JERSEY...
  THIS INCLUDES THE CITY OF TRENTON...
  SOUTHEASTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  EAST CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 300 PM EDT

* AT 203 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  BRISTOL...OR 9 MILES SOUTHWEST OF TRENTON...AND MOVING WEST AT 15
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  BENSALEM...LANGHORNE AROUND 225 PM EDT...
  FEASTERVILLE AROUND 235 PM EDT...
  RICHBORO AROUND 245 PM EDT...
  BRYN ATHYN AROUND 250 PM EDT...
  IVYLAND AROUND 255 PM EDT...
  HATBORO AND WILLOW GROVE AROUND 300 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS!

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 4013 7477 4013 7482 4008 7487 4010 7496
      4012 7496 4013 7500 4011 7505 4015 7524
      4037 7495 4034 7494 4034 7488 4020 7472
TIME...MOT...LOC 1807Z 111DEG 13KT 4012 7486

$$

TFG

1 follow-up statement

786 
WWUS51 KPHI 241839
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
239 PM EDT THU MAY 24 2012

NJC021-PAC017-091-241900-
/O.CON.KPHI.SV.W.0009.000000T0000Z-120524T1900Z/
MERCER NJ-BUCKS PA-MONTGOMERY PA-
239 PM EDT THU MAY 24 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR EAST CENTRAL MONTGOMERY...SOUTHEASTERN BUCKS AND WEST CENTRAL
MERCER COUNTIES...

AT 237 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. DOPPLER RADAR IS
SHOWING AROUND 60 MPH OF WIND APPROACHING NEW BRITAIN IN BUCKS
COUNTY. THIS STORM WAS LOCATED NEAR RICHBORO...OR 13 MILES WEST OF 
TRENTON...MOVING NORTHWEST AT 25 MPH.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS!

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 4023 7478 4022 7482 4021 7486 4018 7489
      4017 7494 4011 7505 4015 7524 4037 7495
      4034 7494 4034 7488 4024 7477
TIME...MOT...LOC 1838Z 140DEG 22KT 4024 7501

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
May 24, 12:52 PM EDT	Special Weather Statement	PHI	Camden, Gloucester	53 min
May 24, 1:06 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Gloucester	94 min
May 24, 1:18 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester	38 min
May 24, 1:19 PM EDT	Special Weather Statement	PHI	Burlington	56 min
May 24, 1:27 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden	48 min
May 24, 1:36 PM EDT	Areal Flood Advisory	PHI	Burlington	84 min
May 24, 1:47 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Monmouth	43 min
May 24, 1:50 PM EDT	Flash Flood Warning	PHI	Burlington	89 min
May 24, 2:01 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Mercer	83 min
May 24, 2:21 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Somerset	97 min
May 24, 2:32 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer	29 min
May 24, 2:36 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer	54 min
May 24, 3:13 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	91 min
May 24, 3:38 PM EDT	Special Weather Statement	PHI	Hunterdon, Somerset	67 min
May 24, 4:23 PM EDT	Special Weather Statement	PHI	Morris, Sussex, Warren	97 min
May 24, 1:57 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	63 min
May 24, 2:26 PM EDT	Special Weather Statement	PHI	Delaware, Montgomery	64 min
May 24, 3:09 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	66 min
May 24, 3:16 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	59 min
May 24, 3:39 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	57 min
May 24, 4:00 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	67 min
May 24, 4:07 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	83 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012 Severe Thunderstorm Warnings in New Jersey, 2012 Every severe thunderstorm warning in 2012

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.