Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 218, NWS Philadelphia/Mount Holly

September 18, 2012Berks County, Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 18, 2012, 1:32 PM EDT for Berks County, Lehigh County, Pennsylvania. It was in force for 43 min. 1 report 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: Sep 18, 2012, 1:32 PM EDT (17:32 UTC)
Expired: Sep 18, 2012, 2:15 PM EDT
In force: 43 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Berks County, PA, Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 149 km from the middle of the area, began a volume at 17:33 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
Sep 18, 1:40 PM EDT	TSTM WND DMG	Jefferson Twp, PA	TREES DOWN.

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
Sep 18, 12:10 PM EDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 5.5 hours before the alert went out and 121 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: 330 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 519 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 265 m²/s²
0-3 km storm-relative helicity: 275 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.3

Open this sounding in Storm Lab

The text

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

150 
WUUS51 KPHI 181732
SVRPHI
PAC011-077-181815-
/O.NEW.KPHI.SV.W.0218.120918T1732Z-120918T1815Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
132 PM EDT TUE SEP 18 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  BERKS COUNTY IN EASTERN PENNSYLVANIA...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA...

* UNTIL 215 PM EDT

* AT 128 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A LINE OF SEVERE THUNDERSTORMS WITH LITTLE OR NO LIGHTNING CAPABLE 
  OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS      
  WERE LOCATED ALONG A LINE EXTENDING FROM NEW TRIPOLI TO 8 MILES    
  SOUTHWEST OF WOMELSDORF...OR ALONG A LINE EXTENDING FROM 8 MILES   
  SOUTHWEST OF LEHIGHTON TO 15 MILES NORTH OF LANCASTER...AND        
  MOVING NORTHEAST AT 40 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  SHOEMAKERSVILLE...LENHARTSVILLE...WERNERSVILLE...JORDAN VALLEY...
  SINKING SPRING...WYOMISSING...LEESPORT...EMERALD...LAURELDALE...
  SLATINGTON...FLEETWOOD...NEFFS...LYONS...SCHNECKSVILLE...
  KUTZTOWN...COFFEETOWN...CLAUSSVILLE AND TOPTON

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS. PEOPLE OUTSIDE SHOULD MOVE TO A 
SHELTER...PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

THIS LINE OF STRONG TO SEVERE THUNDERSTORMS MAY CONTAIN LITTLE OR NO 
LIGHTNING. DO NOT WAIT TO HEAR THUNDER BEFORE TAKING COVER. SEEK 
SHELTER IMMEDIATELY INSIDE A STURDY STRUCTURE AND STAY AWAY FROM 
WINDOWS.

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 PM EDT TUESDAY EVENING
FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

&&

LAT...LON 4051 7640 4052 7624 4058 7606 4058 7602
      4065 7599 4078 7565 4067 7548 4066 7548
      4066 7547 4063 7542 4026 7608 4036 7621
      4038 7626 4049 7643
TIME...MOT...LOC 1731Z 235DEG 36KT 4074 7576 4028 7624

$$

GORSE

1 follow-up statement

392 
WWUS51 KPHI 181745
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
145 PM EDT TUE SEP 18 2012

PAC011-077-181815-
/O.CON.KPHI.SV.W.0218.000000T0000Z-120918T1815Z/
BERKS PA-LEHIGH PA-
145 PM EDT TUE SEP 18 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 PM EDT
FOR LEHIGH AND BERKS COUNTIES...

AT 142 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM EMERALD TO BERNVILLE TO WERNERSVILLE...OR ALONG A LINE
EXTENDING FROM LEHIGHTON TO 14 MILES NORTHWEST OF READING TO 11 MILES
WEST OF READING...MOVING NORTHEAST AT 40 MPH.

THIS LINE HAS LITTLE TO NO LIGHTNING DETECTED WITH IT, AND THERE HAS 
BEEN SOME TREES KNOCKED DOWN IN LEBANON COUNTY.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SINKING
SPRING...WEST WYOMISSING...WHITFIELD...WEST LAWN...CENTERPORT...
HAMBURG...WYOMISSING HILLS...WYOMISSING...WEST READING...
SHOEMAKERSVILLE...LEESPORT...LAURELDALE...TEMPLE...LENHARTSVILLE...
JORDAN VALLEY...FLEETWOOD...NEW TRIPOLI...LYONS...KUTZTOWN...NEFFS...
COFFEETOWN...CLAUSSVILLE...TOPTON...SLATINGTON...SCHNECKSVILLE...
HOKENDAUQUA...FULLERTON...COPLAY AND CATASAUQUA

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS LINE OF STORMS MAY CONTAIN LITTLE OR NO LIGHTNING. DO 
NOT WAIT FOR THUNDER BEFORE TAKING COVER. SEEK SHELTER IMMEDIATELY 
INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS.

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 PM EDT TUESDAY EVENING
FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

&&

LAT...LON 4052 7624 4058 7606 4058 7602 4065 7599
      4078 7565 4067 7548 4066 7548 4066 7547
      4063 7542 4026 7608 4036 7621 4049 7643
TIME...MOT...LOC 1743Z 235DEG 36KT 4081 7563 4051 7607
          4035 7611

$$

GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 18, 4:13 AM EDT	Coastal Flood Advisory	PHI	Delaware, Philadelphia	21 hr
Sep 18, 12:58 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	93 min
Sep 18, 12:59 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	46 min
Sep 18, 1:05 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	115 min
Sep 18, 2:00 PM EDT	Special Weather Statement	PHI	Chester, Montgomery	60 min
Sep 18, 2:18 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	57 min
Sep 18, 2:23 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	30 min
Sep 18, 2:25 PM EDT	Flash Flood Warning	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Sep 18, 2:52 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	17 min
Sep 18, 3:07 PM EDT	Areal Flood Warning	PHI	Berks, Lehigh	8 hr
Sep 18, 3:16 PM EDT	Special Weather Statement	PHI	Monroe	59 min
Sep 18, 3:24 PM EDT	Special Weather Statement	PHI	Berks, Carbon	51 min
Sep 18, 3:52 PM EDT	Special Weather Statement	PHI	Chester	53 min
Sep 18, 4:05 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	55 min
Sep 18, 4:19 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Delaware, Montgomery	56 min
Sep 18, 4:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Monroe, Northampton	52 min
Sep 18, 4:26 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	3 hr
Sep 18, 4:35 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Lehigh, Montgomery	55 min
Sep 18, 5:01 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Lehigh, Montgomery, Northampton and 1 more	59 min
Sep 18, 5:12 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery	63 min
Sep 18, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	78 min
Sep 18, 5:13 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	62 min
Sep 18, 6:00 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	60 min
Sep 18, 6:06 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	54 min
Sep 18, 6:19 PM EDT	Areal Flood Warning	PHI	Carbon, Lehigh, Monroe, Northampton	16 hr
Sep 18, 6:54 PM EDT	Areal Flood Advisory	PHI	Bucks	111 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012 Every severe thunderstorm warning in 2012

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.