Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 4, NWS Philadelphia/Mount Holly

May 16, 2007Bucks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 16, 2007, 2:48 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania. It was in force for 42 min. 2 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 16, 2007, 2:48 PM EDT (18:48 UTC)
Expired: May 16, 2007, 3:30 PM EDT
In force: 42 min
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

Counties Bucks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 84 km from the middle of the area, began a volume at 18:47 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

Time	Report	Where	Remark
May 16, 3:10 PM EDT	TSTM WND DMG	Hatfield, PA	TREES REPORTED DOWN IN HATFIELD AND HORSHAM.
May 16, 3:15 PM EDT	TSTM WND DMG	5 Nw Doylestown, PA	WIRES AND A FEW TREES DOWN AROUND THE COUNTY.

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.

Issued	Product	Office	Lasted
May 16, 1:26 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.8 hours before the alert went out and 120 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 18 J/kg
Mixed-layer CIN: -160 J/kg
Mixed-layer LCL: 1421 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 107 m²/s²
0-3 km storm-relative helicity: 138 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 161848
SVRPHI
PAC017-029-091-161930-
/O.NEW.KPHI.SV.W.0004.070516T1848Z-070516T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
248 PM EDT WED MAY 16 2007

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 330 PM EDT

* AT 247 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR SPRING MOUNT...OR ABOUT 21
  MILES SOUTH OF ALLENTOWN...AND MOVING EAST AT 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PERKASIE...LANSDALE AND 9 MILES SOUTH OF QUAKERTOWN BY 255 PM
  EDT...
  DOYLESTOWN...CHALFONT AND DUBLIN BY 300 PM EDT...
  9 MILES NORTH OF RICHBORO BY 305 PM EDT...

LAT...LON 4052 7537 4007 7578 4007 7527 4023 7488
      4041 7506 4052 7508

$$

MPD

1 follow-up statement

000 
WWUS51 KPHI 161912
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
311 PM EDT WED MAY 16 2007

PAC017-029-091-161930-
/O.CON.KPHI.SV.W.0004.000000T0000Z-070516T1930Z/
CHESTER PA-MONTGOMERY PA-BUCKS PA-
309 PM EDT WED MAY 16 2007

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
BUCKS...MONTGOMERY AND CHESTER COUNTIES...

AT 304 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH. THE STORMS WERE ON A LINE FROM SOUTHWEST CHESTER
COUNTY THROUGH NORTHERN BUCKS COUNTY...AND WERE MOVING EAST AT 40 MPH.

LAT...LON 4052 7537 3982 7593 4007 7527 4023 7488
      4041 7506 4052 7508

$$

MPD

The office that day

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

Issued	Product	Office	Counties	Lasted
May 16, 3:26 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	49 min
May 16, 3:30 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery, Philadelphia	45 min
May 16, 4:16 PM EDT	Severe Thunderstorm Warning	PHI	Chester	44 min
May 16, 4:35 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	40 min
May 16, 4:53 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	52 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2007 Every severe thunderstorm warning in 2007

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.