Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 137, NWS Philadelphia/Mount Holly

July 26, 2009Bucks County, Lehigh County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 26, 2009, 4:06 PM EDT for Bucks County, Lehigh County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 54 min. 9 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 26, 2009, 4:06 PM EDT (20:06 UTC)
Expired
Jul 26, 2009, 5:00 PM EDT
In force
54 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 104 km from the middle of the area, began a volume at 20:09 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 26, 4:25 PM EDTFUNNEL CLOUDFerndale, PAFUNNEL CLOUD SPOTTED OVER FERNDALE.
Jul 26, 4:25 PM EDTHAIL 1.5Ferndale, PAPING BALL SIZE HAIL IN FERNDALE.
Jul 26, 4:50 PM EDTFUNNEL CLOUDFrenchtown, NJROTATING WALL CLOUD WITH FUNNEL CLOUD.
Jul 26, 4:50 PM EDTTSTM WND DMG1 Se Milford, NJTREES DOWN, ROOF OFF BARN, SHED TOTALLY GONE, SWATH OF DAMAGE THROUGH WOODS IN ALEXANDRIA TWP.
Jul 26, 4:50 PM EDTTSTM WND DMG6 S Clinton, NJNUMEROUS TREES DOWN IN PITTOWN.
Jul 26, 4:50 PM EDTHAIL 16 S Clinton, NJQUARTER SIZE HAIL IN PITTOWN
Jul 26, 5:00 PM EDTTSTM WND DMGClinton, NJ4 INCH DIAMETER BRANCHES DOWN.
Jul 26, 5:00 PM EDTHAIL 0.25Clinton, NJQUARTER INCH HAIL IN CLINTON.
Jul 26, 5:00 PM EDTHAIL 1Clinton, NJQUARTER SIZE HAIL IN CLINTON.

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.

IssuedProductOfficeLasted
Jul 26, 3:51 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 8.1 hours before the alert went out and 197 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 2009-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 933 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 2009-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 161 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
933 J/kg
Mixed-layer CIN
-99 J/kg
Mixed-layer LCL
889 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
161 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 262006
SVRPHI
NJC019-041-PAC017-077-095-262100-
/O.NEW.KPHI.SV.W.0137.090726T2006Z-090726T2100Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
406 PM EDT SUN JUL 26 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF ALLENTOWN...
  SOUTHERN NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITIES OF...EASTON...BETHLEHEM...
  NORTHERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHWESTERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 500 PM EDT

* AT 405 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  ZIONSVILLE...OR 9 MILES SOUTH OF ALLENTOWN...AND MOVING NORTHEAST
  AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HELLERTOWN AROUND 420 PM EDT...
  PLEASANT VALLEY AND SPRINGTOWN AROUND 425 PM EDT...
  FERNDALE AND REVERE AROUND 435 PM EDT...
  MILFORD AND FRENCHTOWN AROUND 445 PM EDT...
  BLOOMSBURY AROUND 455 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS 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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN NEW
JERSEY. A SEVERE THUNDERSTORM WATCH ALSO REMAINS IN EFFECT UNTIL 1100
PM EDT SUNDAY EVENING FOR NEW JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 4091 7504 4055 7482 4038 7541 4058 7564
TIME...MOT...LOC 2006Z 244DEG 24KT 4047 7542

$$

NIERENBERG
2 follow-up statements
000 
WWUS51 KPHI 262028
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
428 PM EDT SUN JUL 26 2009

PAC077-262037-
/O.CAN.KPHI.SV.W.0137.000000T0000Z-090726T2100Z/
LEHIGH PA-
428 PM EDT SUN JUL 26 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN LEHIGH COUNTY IS
CANCELLED...

THE STORM THAT PROMPTED THE WARNING HAS MOVED OUT OF THE AREA, 
THEREFORE THE WARNING HAS BEEN CANCELLED.

A SEVERE THUNDERSTORM WATCH ALSO REMAINS IN EFFECT UNTIL 1100 PM EDT 
SUNDAY EVENING FOR NEW JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 4043 7529 4061 7536 4091 7504 4055 7482
TIME...MOT...LOC 2027Z 246DEG 17KT 4054 7519

$$

NJC019-041-PAC017-095-262100-
/O.CON.KPHI.SV.W.0137.000000T0000Z-090726T2100Z/
WARREN NJ-HUNTERDON NJ-NORTHAMPTON PA-BUCKS PA-
428 PM EDT SUN JUL 26 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM EDT
FOR NORTH CENTRAL BUCKS...SOUTHEASTERN NORTHAMPTON...NORTHERN
HUNTERDON AND SOUTHWESTERN WARREN COUNTIES...

AT 425 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 FERNDALE...OR 10 MILES SOUTH OF EASTON...MOVING
NORTHEAST AT 25 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  ERWINNA BY 440 PM EDT...
  MILFORD AND FRENCHTOWN BY 445 PM EDT...
  BLOOMSBURY BY 450 PM EDT...
  BLOOMSBURY BY 455 PM EDT...
  CLINTON BY 500 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4043 7529 4061 7536 4091 7504 4055 7482
TIME...MOT...LOC 2027Z 246DEG 20KT 4054 7519

$$

GORSE
000 
WWUS51 KPHI 262040
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
440 PM EDT SUN JUL 26 2009

NJC019-041-PAC017-095-262100-
/O.CON.KPHI.SV.W.0137.000000T0000Z-090726T2100Z/
WARREN NJ-HUNTERDON NJ-NORTHAMPTON PA-BUCKS PA-
440 PM EDT SUN JUL 26 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM EDT
FOR NORTH CENTRAL BUCKS...EAST CENTRAL NORTHAMPTON...NORTHERN
HUNTERDON AND SOUTHWESTERN WARREN COUNTIES...

AT 437 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
LOCATED NEAR MILFORD...OR 10 MILES SOUTHEAST OF EASTON...MOVING
NORTHEAST AT 25 MPH.

AT 435 PM...A TRAINED WEATHER SPOTTER IN FERNDALE REPORTED HAIL 
RANGING FROM NICKEL TO PING PONG BALL SIZE.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  BLOOMSBURY BY 445 PM EDT...
  CLINTON...ANNANDALE...HIGH BRIDGE AND GLEN GARDNER BY 500 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK 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.

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.

&&

LAT...LON 4046 7516 4064 7526 4091 7504 4055 7482
TIME...MOT...LOC 2039Z 246DEG 20KT 4058 7507

$$

GORSE

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 26, 3:07 AM EDTFlash Flood WatchPHIBerks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more20 hr
Jul 26, 7:05 PM EDTSevere Thunderstorm WarningPHIChester70 min
Jul 25, 11:08 PM EDTFlash Flood WarningPHISussex, Warren2 hr
Jul 26, 12:15 AM EDTFlash Flood WarningPHISussex90 min
Jul 26, 3:26 AM EDTSmall Craft AdvisoryPHI30 hr
Jul 26, 3:29 PM EDTSevere Thunderstorm WarningPHIMonmouth61 min
Jul 26, 3:30 PM EDTSpecial Marine WarningPHI60 min
Jul 26, 4:55 PM EDTTornado WarningPHIHunterdon, Middlesex, Morris, Somerset55 min
Jul 26, 7:07 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Monmouth53 min
Jul 26, 7:40 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Monmouth, Ocean65 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.