Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 158, NWS Philadelphia/Mount Holly

August 4, 2012Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 4, 2012, 1:46 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 44 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
Aug 4, 2012, 1:46 PM EDT (17:46 UTC)
Expired
Aug 4, 2012, 2:30 PM EDT
In force
44 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 58 km from the middle of the area, began a volume at 17:49 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

TimeReportWhereRemark
Aug 4, 2:00 PM EDTTSTM WND DMGHorsham Twp, PATREES AND WIRES DOWN IN HORSHAM TWP.
Aug 4, 2:10 PM EDTTSTM WND DMGHorsham, PAMULTIPLE LARGE TREE BRANCHES DOWN ALONG MAPLE AVE IN HORSHAM. ALSO... FENCE BLOWN OVER ALONG ROUTE 611.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 5.8 hours before the alert went out and 199 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-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2012-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2028 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2012-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
2028 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
802 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
22 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

411 
WUUS51 KPHI 041746
SVRPHI
PAC017-091-041830-
/O.NEW.KPHI.SV.W.0158.120804T1746Z-120804T1830Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
146 PM EDT SAT AUG 4 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 230 PM EDT

* AT 145 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
  JENKINTOWN...AND MOVING NORTH AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HATBORO AROUND 200 PM EDT...
  IVYLAND AROUND 210 PM EDT...
  RICHBORO AROUND 215 PM EDT...
  DOYLESTOWN AND 6 MILES SOUTHEAST OF ROBESONIA AROUND 230 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...LARGE HAIL...AND DEADLY CLOUD TO
GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT 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 7481 4010 7485 4015 7506 4005 7510
      4008 7517 4007 7519 4009 7522 4008 7524
      4010 7534 4040 7522 4033 7492 4029 7486
      4024 7483 4021 7477
TIME...MOT...LOC 1746Z 196DEG 14KT 4013 7513

$$

IOVINO
1 follow-up statement
289 
WWUS51 KPHI 041802
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
202 PM EDT SAT AUG 4 2012

PAC017-091-041830-
/O.CON.KPHI.SV.W.0158.000000T0000Z-120804T1830Z/
BUCKS PA-MONTGOMERY PA-
202 PM EDT SAT AUG 4 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 PM EDT
FOR EAST CENTRAL MONTGOMERY AND SOUTHERN BUCKS COUNTIES...

AT 200 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 HATBORO...MOVING NORTH AT 15 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  IVYLAND AND CHURCHVILLE BY 210 PM EDT...
  RICHBORO BY 215 PM EDT...
  NEW BRITAIN BY 225 PM EDT...
  DOYLESTOWN...ROBESONIA AND 6 MILES SOUTH OF GARDENVILLE BY 230 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.

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 7481 4010 7485 4015 7506 4008 7509
      4015 7532 4040 7522 4033 7492 4029 7486
      4024 7483 4021 7477
TIME...MOT...LOC 1802Z 196DEG 14KT 4019 7511

$$

IOVINO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 1:12 PM EDTSpecial Weather StatementPHIPhiladelphia63 min
Aug 4, 1:26 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia34 min
Aug 4, 2:51 PM EDTSpecial Weather StatementPHINorthampton54 min
Aug 4, 3:21 PM EDTSevere Thunderstorm WarningPHIBucks, Lehigh, Monroe, Northampton54 min
Aug 4, 3:55 PM EDTSpecial Weather StatementPHILebanon65 min
Aug 4, 4:08 PM EDTSpecial Weather StatementPHICarbon, Monroe52 min
Aug 4, 4:49 PM EDTSpecial Weather StatementPHICarbon, Monroe56 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012Every 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.