Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 99, NWS Philadelphia/Mount Holly

July 18, 20124 counties in Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 18, 2012, 3:13 PM EDT for 4 counties in Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 47 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: Jul 18, 2012, 3:13 PM EDT (19:13 UTC)
Expired: Jul 18, 2012, 4:00 PM EDT
In force: 47 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

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

The radar

The Philadelphia radar (KDIX), 111 km from the middle of the area, began a volume at 19:14 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
Jul 18, 3:22 PM EDT	TSTM WND DMG	Bethlehem, PA	NUMEROUS LARGE TREE BRANCHES DOWN WITH SOME POWER OUTAGES. UNION BLVD AND PENNSYLVANIA AVE
Jul 18, 3:40 PM EDT	TSTM WND DMG	Hanover Twp, PA	BRANCHES DOWN... 1 TREE UPROOTED. TIME EST.

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
Jul 18, 12:41 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.2 hours before the alert went out and 150 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: 884 J/kg
Mixed-layer CIN: -169 J/kg
Mixed-layer LCL: 1666 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 10 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.

891 
WUUS51 KPHI 181913
SVRPHI
NJC019-041-PAC011-017-077-095-182000-
/O.NEW.KPHI.SV.W.0099.120718T1913Z-120718T2000Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
313 PM EDT WED JUL 18 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF ALLENTOWN...
  SOUTHERN NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  THIS INCLUDES THE CITY OF EASTON...
  NORTHWESTERN HUNTERDON COUNTY IN NORTHWEST NEW JERSEY...
  SOUTHWESTERN WARREN COUNTY IN NORTHWEST NEW JERSEY...
  NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 400 PM EDT

* AT 310 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM BEERSVILLE TO NEFFS TO KUTZTOWN...OR ALONG A LINE EXTENDING
  FROM 12 MILES NORTHWEST OF EASTON TO 10 MILES SOUTHEAST OF
  LEHIGHTON TO 15 MILES NORTH OF READING...AND MOVING EAST AT 25 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  COFFEETOWN...CLAUSSVILLE AND LYONS AROUND 320 PM EDT...
  BELFAST...TOPTON...NORTHAMPTON AND NAZARETH AROUND 325 PM EDT...
  TATAMY AROUND 330 PM EDT...
  ANCIENT OAKS AROUND 335 PM EDT...
  ALLENTOWN AROUND 340 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
WEDNESDAY EVENING FOR NORTHERN DELAWARE AND NORTHEASTERN MARYLAND AND
NEW JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 4072 7571 4081 7541 4076 7485 4074 7483
      4074 7478 4066 7505 4043 7543 4051 7596
TIME...MOT...LOC 1912Z 276DEG 24KT 4077 7540 4071 7559
          4054 7581

$$

DRAG

2 follow-up statements

277 
WWUS51 KPHI 181939
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
339 PM EDT WED JUL 18 2012

NJC019-041-PAC011-017-077-095-182000-
/O.CON.KPHI.SV.W.0099.000000T0000Z-120718T2000Z/
WARREN NJ-HUNTERDON NJ-BERKS PA-BUCKS PA-LEHIGH PA-NORTHAMPTON PA-
339 PM EDT WED JUL 18 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT
FOR SOUTHERN NORTHAMPTON...LEHIGH...NORTHWESTERN BUCKS...NORTHEASTERN
BERKS...NORTHWESTERN HUNTERDON AND SOUTHWESTERN WARREN COUNTIES...

AT 335 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 TATAMY TO BETHLEHEM TO MACUNGIE...OR ALONG A LINE
EXTENDING FROM EASTON TO 7 MILES NORTHEAST OF ALLENTOWN TO 6 MILES
SOUTHWEST OF ALLENTOWN...MOVING EAST AT 30 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  WILSON...WEST EASTON...OLD ORCHARD AND GLENDON BY 345 PM EDT...
  HELLERTOWN AND PHILLIPSBURG BY 350 PM EDT...
  PLEASANT VALLEY...BRASS CASTLE...SPRINGTOWN AND COOPERSBURG BY 355
  PM EDT...

THERE HAVE BEEN REPORTS OF DAMAGING WIND NEAR ALLENTOWN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
WEDNESDAY EVENING FOR NORTHERN DELAWARE AND NORTHEASTERN MARYLAND AND
NEW JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 4052 7576 4069 7557 4078 7534 4076 7485
      4074 7483 4074 7478 4066 7505 4043 7543
TIME...MOT...LOC 1938Z 276DEG 24KT 4075 7517 4065 7534
          4052 7552

$$
DRAG

199 
WWUS51 KPHI 181956
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
356 PM EDT WED JUL 18 2012

NJC019-041-PAC011-017-077-095-182006-
/O.EXP.KPHI.SV.W.0099.000000T0000Z-120718T2000Z/
WARREN NJ-HUNTERDON NJ-BERKS PA-BUCKS PA-LEHIGH PA-NORTHAMPTON PA-
356 PM EDT WED JUL 18 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN NORTHAMPTON...
LEHIGH...NORTHWESTERN BUCKS...NORTHEASTERN BERKS...NORTHWESTERN
HUNTERDON AND SOUTHWESTERN WARREN COUNTIES WILL EXPIRE AT 400 PM
EDT...

THE STORMS HAVE WEAKENED.  

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
WEDNESDAY EVENING FOR NORTHERN DELAWARE AND NORTHEASTERN MARYLAND AND
NEW JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 4052 7576 4069 7557 4078 7534 4076 7485
      4074 7483 4074 7478 4066 7505 4043 7543
TIME...MOT...LOC 1956Z 276DEG 24KT 4074 7501 4057 7532
          4051 7536

$$

DRAG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 1:27 PM EDT	Special Weather Statement	PHI	Monroe	33 min
Jul 18, 1:53 PM EDT	Special Weather Statement	PHI	Bucks	37 min
Jul 18, 2:07 PM EDT	Special Weather Statement	PHI	Berks	38 min
Jul 18, 2:12 PM EDT	Severe Thunderstorm Warning	PHI	Berks	48 min
Jul 18, 2:15 PM EDT	Special Weather Statement	PHI	Monroe	60 min
Jul 18, 2:23 PM EDT	Special Weather Statement	PHI	Northampton	67 min
Jul 18, 2:43 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	47 min
Jul 18, 3:04 PM EDT	Special Weather Statement	PHI	Berks, Lehigh, Northampton	41 min
Jul 18, 3:26 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	49 min
Jul 18, 3:36 PM EDT	Special Weather Statement	PHI	Berks	54 min
Jul 18, 3:43 PM EDT	Special Weather Statement	PHI	Carbon	47 min
Jul 18, 3:51 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	28 min
Jul 18, 3:52 PM EDT	Flash Flood Warning	PHI	Monroe, Northampton	113 min
Jul 18, 4:22 PM EDT	Special Weather Statement	PHI	Bucks	23 min
Jul 18, 4:28 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	32 min
Jul 18, 5:30 PM EDT	Special Weather Statement	PHI	Bucks	60 min
Jul 18, 5:51 PM EDT	Special Weather Statement	PHI	Philadelphia	54 min
Jul 18, 12:51 PM EDT	Special Weather Statement	PHI	Sussex	54 min
Jul 18, 1:02 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	34 min
Jul 18, 1:11 PM EDT	Special Weather Statement	PHI	Sussex	34 min
Jul 18, 1:23 PM EDT	Special Weather Statement	PHI	Morris	37 min
Jul 18, 1:43 PM EDT	Areal Flood Advisory	PHI	Sussex	2 hr
Jul 18, 1:49 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	26 min
Jul 18, 2:46 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex	29 min
Jul 18, 3:00 PM EDT	Special Weather Statement	PHI	Monmouth	45 min
Jul 18, 3:18 PM EDT	Special Marine Warning	PHI		42 min
Jul 18, 3:25 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	65 min
Jul 18, 3:29 PM EDT	Special Weather Statement	PHI	Monmouth	46 min
Jul 18, 3:59 PM EDT	Flash Flood Warning	PHI	Morris, Sussex	107 min
Jul 18, 4:03 PM EDT	Special Weather Statement	PHI	Hunterdon	42 min
Jul 18, 4:17 PM EDT	Special Weather Statement	PHI	Morris	43 min
Jul 18, 4:30 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Morris, Somerset	45 min
Jul 18, 4:41 PM EDT	Special Weather Statement	PHI	Mercer	34 min
Jul 18, 4:53 PM EDT	Special Weather Statement	PHI	Mercer	22 min
Jul 18, 5:01 PM EDT	Special Weather Statement	PHI	Middlesex	29 min
Jul 18, 5:07 PM EDT	Special Marine Warning	PHI		38 min
Jul 18, 5:11 PM EDT	Special Weather Statement	PHI	Middlesex, Somerset	64 min
Jul 18, 5:12 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Middlesex, Somerset	81 min
Jul 18, 5:19 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth	41 min
Jul 18, 5:26 PM EDT	Special Marine Warning	PHI		34 min
Jul 18, 5:33 PM EDT	Special Weather Statement	PHI	Mercer	57 min
Jul 18, 5:44 PM EDT	Special Marine Warning	PHI		31 min
Jul 18, 6:00 PM EDT	Special Marine Warning	PHI		60 min
Jul 18, 6:09 PM EDT	Areal Flood Advisory	PHI	Burlington, Monmouth, Ocean	68 min
Jul 18, 6:32 PM EDT	Special Weather Statement	PHI	Ocean	43 min
Jul 18, 6:45 PM EDT	Special Weather Statement	PHI	Cape May, Cumberland	60 min
Jul 18, 6:51 PM EDT	Special Marine Warning	PHI		39 min
Jul 18, 6:51 PM EDT	Special Marine Warning	PHI		39 min
Jul 18, 7:17 PM EDT	Special Weather Statement	PHI	Cape May	58 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2012 Severe Thunderstorm Warnings in New Jersey, 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.