Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 3, NWS Philadelphia/Mount Holly

March 29, 2009Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Mar 29, 2009, 5:27 PM EDT for Lehigh County, Pennsylvania. It was in force for 63 min. 6 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
Mar 29, 2009, 5:27 PM EDT (21:27 UTC)
Expired
Mar 29, 2009, 6:30 PM EDT
In force
63 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 127 km from the middle of the area, began a volume at 21:29 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
Mar 29, 5:40 PM EDTHAIL 1Alburtis, PAQUARTER SIZE HAIL REPORTED IN LONGSWAMP.
Mar 29, 5:45 PM EDTHAIL 1.5Macungie, PASILVER DOLLAR SIZED HAIL REPORTED IN UPPER MACUNGIE AND MACUNGIE TOWNSHIPS.
Mar 29, 5:55 PM EDTHAIL 0.88Allentown, PANICKEL SIZE HAIL REPORTED IN ALLENTOWN AND ACCUMULATING ON THE GROUND.
Mar 29, 6:00 PM EDTHAIL 0.885 E Claussville, PANICKEL SIZE HAIL REPORTED IN EAST TEXAS.
Mar 29, 6:15 PM EDTTSTM WND DMGEmmaus, PATREE DAMAGE REPORTED IN EMMAUS.
Mar 29, 6:20 PM EDTHAIL 1.75Ancient Oaks, PAGOLF BALL SIZED REPORTED IN ANCIENT OAKS AND THE GROUND WAS COVERED.

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, 9.5 hours before the alert went out and 232 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 2009-03-29Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2009-03-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 474 square meters per square second.1939587897Sfc1 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
424 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
474 m²/s²
0-3 km storm-relative helicity
554 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.

000 
WUUS51 KPHI 292127
SVRPHI
PAC077-292230-
/O.NEW.KPHI.SV.W.0003.090329T2127Z-090329T2230Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
527 PM EDT SUN MAR 29 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF ALLENTOWN...

* UNTIL 630 PM EDT

* AT 525 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
  STORM WAS LOCATED 18 MILES SOUTH OF WANAMAKERS...OR NEAR READING...
  AND MOVING NORTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  CLAUSSVILLE...ANCIENT OAKS AND 9 MILES SOUTHEAST OF NEW TRIPOLI BY
  605 PM EDT...
  8 MILES NORTHWEST OF EMMAUS BY 610 PM EDT...
  SCHNECKSVILLE BY 615 PM EDT...
  NEFFS...6 MILES NORTHWEST OF ALLENTOWN AND 8 MILES SOUTHEAST OF
  EMERALD BY 620 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS

&&

LAT...LON 4056 7538 4046 7556 4068 7590 4076 7574
      4078 7565
TIME...MOT...LOC 2127Z 225DEG 24KT 4041 7587

$$

STAUBER
2 follow-up statements
000 
WWUS51 KPHI 292145
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
545 PM EDT SUN MAR 29 2009

PAC077-292230-
/O.CON.KPHI.SV.W.0003.000000T0000Z-090329T2230Z/
LEHIGH PA-
545 PM EDT SUN MAR 29 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR LEHIGH COUNTY...

AT 545 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL.  THIS STORM WAS LOCATED NEAR ANCIENT OAKS...OR 8 MILES
SOUTHWEST OF ALLENTOWN...MOVING NORTHEAST AT 30 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  EMMAUS BY 555 PM EDT...
  ALLENTOWN...7 MILES SOUTHEAST OF SCHNECKSVILLE AND 8 MILES
  SOUTHEAST OF NEFFS BY 600 PM EDT...
  FULLERTON BY 605 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.

&&

LAT...LON 4056 7538 4046 7556 4068 7590 4076 7574
      4078 7565
TIME...MOT...LOC 2146Z 225DEG 24KT 4055 7560

$$

STAUBER
000 
WWUS51 KPHI 292228
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
628 PM EDT SUN MAR 29 2009

PAC077-292237-
/O.EXP.KPHI.SV.W.0003.000000T0000Z-090329T2230Z/
LEHIGH PA-
628 PM EDT SUN MAR 29 2009

...THE SEVERE THUNDERSTORM WARNING FOR LEHIGH COUNTY WILL EXPIRE AT
630 PM EDT...

STORMS HAVE MOVED EAST OF LEHIGH COUNTY. NO OTHER SEVERE WEATHER IS 
EXPECTED THIS EVENING.

LAT...LON 4056 7538 4046 7556 4068 7590 4076 7574
      4078 7565
TIME...MOT...LOC 2227Z 225DEG 24KT 4074 7535

$$

AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 29, 4:41 PM EDTSevere Thunderstorm WarningPHIBerks94 min
Mar 29, 4:58 PM EDTTornado WarningPHIBerks62 min
Mar 29, 5:11 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh64 min
Mar 29, 5:55 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Lehigh, Montgomery, Northampton50 min
Mar 29, 6:11 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia64 min
Mar 29, 7:09 PM EDTSevere Thunderstorm WarningPHIBucks51 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 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.