Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 28, NWS Philadelphia/Mount Holly

May 23, 2009Bucks County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 23, 2009, 4:40 PM EDT for Bucks County, Northampton County, Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 37 min. 3 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 23, 2009, 4:40 PM EDT (20:40 UTC)
Expired
May 23, 2009, 5:17 PM EDT
In force
37 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

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

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 20:43 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
May 23, 4:47 PM EDTHAIL 0.25Phillipsburg, NJQUARTER SIZE HAIL.
May 23, 4:47 PM EDTHAIL 1Phillipsburg, NJQUARTER SIZE HAIL.
May 23, 4:52 PM EDTHAIL 0.75Alpha, NJPENNY SIZE HAIL IN ALPHA.

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, 8.7 hours before the alert went out and 184 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 2009-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2009-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1115 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
154 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.

000 
WUUS51 KPHI 232040
SVRPHI
NJC019-041-PAC017-095-232145-
/O.NEW.KPHI.SV.W.0028.090523T2040Z-090523T2145Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
440 PM EDT SAT MAY 23 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF EASTON...
  NORTHWESTERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  EXTREME NORTH CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 545 PM EDT

* AT 440 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
  FORKS AND EASTON...AND MOVING EAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  EASTON AND FORKS BY 445 PM EDT...
  ALPHA BY 455 PM EDT...
  HARMONY BY 500 PM EDT...
  BLOOMSBURY BY 510 PM EDT...
  BRASS CASTLE BY 520 PM EDT...
  PLEASANT VALLEY BY 525 PM EDT...

LAT...LON 4081 7490 4051 7492 4060 7524 4077 7524
TIME...MOT...LOC 2040Z 271DEG 16KT 4069 7526

$$

IOVINO
2 follow-up statements
000 
WWUS51 KPHI 232103
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
503 PM EDT SAT MAY 23 2009

PAC017-095-232112-
/O.CAN.KPHI.SV.W.0028.000000T0000Z-090523T2145Z/
NORTHAMPTON PA-BUCKS PA-
503 PM EDT SAT MAY 23 2009

...THE SEVERE THUNDERSTORM WARNING FOR EXTREME NORTH CENTRAL BUCKS
AND CENTRAL NORTHAMPTON COUNTIES IS CANCELLED...

THE SEVERE THUNDERSTORM HAS MOVED TO THE EAST.

LAT...LON 4081 7490 4051 7492 4060 7514 4071 7511
TIME...MOT...LOC 2102Z 282DEG 17KT 4066 7508

$$

NJC019-041-232145-
/O.CON.KPHI.SV.W.0028.000000T0000Z-090523T2145Z/
WARREN NJ-HUNTERDON NJ-
503 PM EDT SAT MAY 23 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR NORTHWESTERN HUNTERDON AND SOUTH CENTRAL WARREN COUNTIES...

AT 501 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 BLOOMSBURY...MOVING EAST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  PLEASANT VALLEY BY 510 PM EDT...
  HAMPTON BY 515 PM EDT...
  GLEN GARDNER BY 520 PM EDT...

LAT...LON 4081 7490 4051 7492 4060 7514 4071 7511
TIME...MOT...LOC 2102Z 282DEG 17KT 4066 7508

$$

IOVINO
000 
WWUS51 KPHI 232117
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
517 PM EDT SAT MAY 23 2009

NJC019-041-232127-
/O.CAN.KPHI.SV.W.0028.000000T0000Z-090523T2145Z/
WARREN NJ-HUNTERDON NJ-
517 PM EDT SAT MAY 23 2009

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN HUNTERDON AND
SOUTH CENTRAL WARREN COUNTIES IS CANCELLED...

THE THUNDERSTORM HAS WEAKENED CONSIDERABLY.  AS A RESULT...THE 
WARNING HAS BEEN CANCELLED.

LAT...LON 4081 7490 4051 7492 4060 7514 4071 7511
TIME...MOT...LOC 2117Z 282DEG 17KT 4064 7499

$$

IOVINO

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 4:16 PM EDTSevere Thunderstorm WarningPHINorthampton44 min
May 23, 4:34 PM EDTAreal Flood AdvisoryPHILehigh, Northampton85 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.