Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 74, NWS Philadelphia/Mount Holly

July 4, 2012Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 4, 2012, 11:45 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 28 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 4, 2012, 11:45 PM EDT (03:45 UTC)
Expired
Jul 5, 2012, 12:13 AM EDT
In force
28 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 03:46 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
Jul 4, 11:50 PM EDTHAIL 0.75Warrington, PA
Jul 4, 11:58 PM EDTTSTM WND DMGWarrington, PATREE DOWN ON WIRES NEAR THE WARRINGTON AREA.

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 00:00Z, 3.8 hours before the alert went out and 213 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 00:00Z on 2012-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1802 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 00:00Z on 2012-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 square meters per square second.193958Sfc1 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
1802 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
1100 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
189 m²/s²
Significant tornado parameter
0.7
Supercell composite
3.9

Open this sounding in Storm Lab

The text

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

110 
WUUS51 KPHI 050345
SVRPHI
PAC017-091-050430-
/O.NEW.KPHI.SV.W.0074.120705T0345Z-120705T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1145 PM EDT WED JUL 4 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 1230 AM EDT

* AT 1142 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR SOUDERTON...OR 18 MILES   
SOUTH OF ALLENTOWN...AND MOVING SOUTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SOUDERTON AROUND 1150 PM EDT...
  HATFIELD AND FRICKS AROUND 1155 PM EDT...
  LANSDALE AND CHALFONT AROUND MIDNIGHT EDT...
  AMBLER AND 6 MILES NORTHEAST OF PLYMOUTH MEETING AROUND 1210 AM
  EDT...
  WILLOW GROVE AND HATBORO AROUND 1215 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

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 4016 7497 4007 7538 4037 7558 4046 7535
TIME...MOT...LOC 0344Z 321DEG 29KT 4033 7537

$$

GORSE
1 follow-up statement
264 
WWUS51 KPHI 050413
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1213 AM EDT THU JUL 5 2012

PAC017-091-050422-
/O.CAN.KPHI.SV.W.0074.000000T0000Z-120705T0430Z/
BUCKS PA-MONTGOMERY PA-
1213 AM EDT THU JUL 5 2012

...THE SEVERE THUNDERSTORM WARNING FOR MONTGOMERY AND CENTRAL BUCKS
COUNTIES IS CANCELLED...
 
THE THUNDERSTORM HAS WEAKENED BELOW SEVERE THRESHOLDS, THEREFORE THE 
WARNING HAS BEEN CANCELLED. THIS STORM HOWEVER CONTINUES TO PRODUCE 
DOWNPOURS ALONG WITH CLOUD TO GROUND LIGHTNING.

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 4016 7497 4007 7538 4037 7558 4046 7535
TIME...MOT...LOC 0412Z 321DEG 29KT 4015 7518

$$

GORSE

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 4, 9:18 PM EDTSpecial Weather StatementPHICarbon, Monroe57 min
Jul 4, 10:37 PM EDTSpecial Weather StatementPHIBerks, Lehigh38 min
Jul 4, 11:07 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh27 min
Jul 4, 11:14 PM EDTSpecial Weather StatementPHIBucks, Lehigh46 min
Jul 4, 11:37 PM EDTSpecial Weather StatementPHIMontgomery38 min
Jul 5, 1:34 AM EDTSpecial Weather StatementPHILehigh56 min
Jul 5, 1:41 AM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Carbon, Lehigh, Montgomery, Northampton34 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.