Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 196, NWS Philadelphia/Mount Holly

August 11, 2009Warren County, New Jersey; Monroe County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 11, 2009, 4:19 PM EDT for Warren County, New Jersey; Monroe County, Northampton County, Pennsylvania. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 11, 2009, 4:19 PM EDT (20:19 UTC)
Expired
Aug 11, 2009, 4:53 PM EDT
In force
34 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Warren County, NJ, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 117 km from the middle of the area, began a volume at 20:20 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.

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.3 hours before the alert went out and 175 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, Phillips Aaf/Abe, MD at 12:00Z on 2009-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 93 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phillips Aaf/Abe, MD at 12:00Z on 2009-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -52 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
93 J/kg
Mixed-layer CIN
-161 J/kg
Mixed-layer LCL
1076 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-52 m²/s²
0-3 km storm-relative helicity
27 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.

000 
WUUS51 KPHI 112019
SVRPHI
NJC041-PAC089-095-112115-
/O.NEW.KPHI.SV.W.0196.090811T2019Z-090811T2115Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
419 PM EDT TUE AUG 11 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF EASTON...
  SOUTH CENTRAL MONROE COUNTY IN NORTHEAST PENNSYLVANIA...
  WARREN COUNTY IN NORTHWEST NEW JERSEY...

* UNTIL 515 PM EDT

* AT 417 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  SAYLORSBURG...OR 13 MILES SOUTH OF MOUNT POCONO...AND MOVING
  SOUTHEAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  STORMVILLE AROUND 425 PM EDT...
  PEN ARGYL AND WIND GAP AROUND 430 PM EDT...
  BANGOR AND EAST BANGOR AROUND 435 PM EDT...
  BELVIDERE AND HARMONY AROUND 450 PM EDT...
  ROXBURG AROUND 455 PM EDT...
  OXFORD AROUND 500 PM 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 LIGHTNING IS ONE OF NATURES GREATEST KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...HEAVY RAIN WILL OCCUR
WITH THESE STORMS AND CAUSE LOW-LYING AND POOR DRAINAGE FLOODING.

&&

LAT...LON 4091 7479 4071 7498 4062 7522 4091 7550
      4105 7535
TIME...MOT...LOC 2019Z 308DEG 23KT 4092 7532

$$
1 follow-up statement
000 
WWUS51 KPHI 112053
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
453 PM EDT TUE AUG 11 2009

NJC041-PAC089-095-112101-
/O.CAN.KPHI.SV.W.0196.000000T0000Z-090811T2115Z/
WARREN NJ-NORTHAMPTON PA-MONROE PA-
453 PM EDT TUE AUG 11 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL MONROE...EASTERN
NORTHAMPTON AND WARREN COUNTIES IS CANCELLED...

THUNDERSTORMS WILL CONTINUE TO AFFECT EASTERN NORTHAMPTON COUNTY 
PENNSYLVANIA AND CENTRAL WARREN COUNTY NEW JERSEY FROM BLAIRSTOWN 
SOUTH TO WASHINGTON THROUGH 530 PM...BUT THUNDERSTORMS HAVE WEAKENED 
BELOW SEVERE LEVELS.


LAT...LON 4091 7479 4071 7498 4062 7522 4091 7550
      4105 7535
TIME...MOT...LOC 2051Z 308DEG 23KT 4079 7511

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 8:08 PM EDTSevere Thunderstorm WarningPHISussex37 min
Aug 11, 3:47 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe43 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2009Severe Thunderstorm Warnings in New Jersey, 2009Every severe thunderstorm warning in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.