Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 76, NWS Philadelphia/Mount Holly

July 1, 2001Berks County, Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 1, 2001, 4:35 PM EDT for Berks County, Bucks County, Montgomery County, Pennsylvania. It was in force for 40 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 1, 2001, 4:35 PM EDT (20:35 UTC)
Expired
Jul 1, 2001, 5:15 PM EDT
In force
40 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Berks County, PA, Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 20:38 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 1, 4:45 PM EDTThunderstorm Wind 52 ECountywide, PA
Jul 1, 5:00 PM EDTThunderstorm Wind 52 ECountywide, PA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 1, 12:00 PM EDTSevere Thunderstorm WatchSPC6 hr
Jul 1, 4:30 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.6 hours before the alert went out and 225 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, Washington/Dulle, VA at 12:00Z on 2001-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 737 joules per kilogram.LCLLFCEL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2001-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
737 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
1231 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.1
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 012036
SVRPHI

PAC011-017-091-012115-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
435 PM EDT SUN JUL 1 2001

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN BERKS COUNTY IN EASTERN PENNSYLVANIA.
  NORTHWESTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA.
  NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA.

* UNTIL 515 PM EDT.

* AT 433 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM... ALONG A LINE EXTENDING FROM 13 MILES
  NORTHEAST OF QUAKERTOWN TO READING...MOVING EAST AT 20 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  EAST GREENVILLE...POTTSTOWN AT 510 PM.
  QUAKERTOWN...PERKASIE...DUBLIN...SPRING MOUNT AT 515 PM.

HAIL UP TO THE SIZE OF GOLFBALLS...AND WINDS GREATER THAN 55
MILES AN HOUR...ARE EXPECTED FROM THIS STORM. SEEK SHELTER IN A
STURDY STRUCTURE UNTIL THE STORM HAS PASSED.

FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER
RADIO...YOUR LOCAL RADIO OR TELEVISION STATION...OR YOUR CABLE
TELEVISION OUTLET.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM SUNDAY
EVENING FOR NORTHWESTERN NEW JERSEY. A SEVERE THUNDERSTORM WATCH ALSO
REMAINS IN EFFECT UNTIL 900 PM SUNDAY EVENING FOR NORTHERN DELAWARE
AND NORTHEAST MARYLAND AND NORTHWESTERN NEW JERSEY AND SOUTHEASTERN
PENNSYLVANIA. 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 10:53 PM EDTSevere Thunderstorm WarningPHIBucks52 min
Jul 1, 1:09 PM EDTSevere Thunderstorm WarningPHIMonroe36 min
Jul 1, 1:20 PM EDTSevere Thunderstorm WarningPHICarbon25 min
Jul 1, 1:26 PM EDTSevere Thunderstorm WarningPHIBerks64 min
Jul 1, 2:03 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh42 min
Jul 1, 2:44 PM EDTSevere Thunderstorm WarningPHIBucks, Northampton61 min
Jul 1, 4:06 PM EDTSevere Thunderstorm WarningPHINorthampton39 min
Jul 1, 5:15 PM EDTSevere Thunderstorm WarningPHIBucks45 min
Jul 1, 5:15 PM EDTSevere Thunderstorm WarningPHIChester, Montgomery45 min
Jul 1, 6:31 PM EDTSevere Thunderstorm WarningPHIPhiladelphia29 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2001Every severe thunderstorm warning in 2001

Sources

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