Alert archive / Pennsylvania / Tornado Warnings in 2017

Tornado Warning 13, NWS Philadelphia/Mount Holly

August 22, 2017Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this tornado warning at Aug 22, 2017, 9:40 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 20 min. 3 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: Aug 22, 2017, 9:40 PM EDT (01:40 UTC)
Expired: Aug 22, 2017, 10:00 PM EDT
In force: 20 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Berks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 125 km from the middle of the area, began a volume at 01:40 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
Aug 22, 9:45 PM EDT	TSTM WND DMG	2 Ene Brecknock Twp, PA	ROOF BLOWN OFF A BUILDING AT THE GREEN HILLS AUCTION CENTER ON ROUTE 568 IN BRECKNOCK TOWNSHIP. SOME OTHER BUILDINGS IN THE AREA HAD SOME DAMAGE AND TREES WERE BLOWN OVER. TIME ESTIMATED FROM RADAR.
Aug 22, 9:47 PM EDT	TSTM WND DMG	1 Nnw Beckersville, PA	TREE AND WIRES DOWN ON KURTZ MILL ROAD IN ROBESON TWP. TIME ESTIMATED BY RADAR.
Aug 22, 9:58 PM EDT	TSTM WND DMG	1 W Halfway House, PA	TREE BLOWN DOWN ON LEVENGOOD ROAD NEAR THE BERKS/MONTGOMERY COUNTY LINE. TIME ESTIMATED BY RADAR.

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
Aug 22, 4:19 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.7 hours before the alert went out and 196 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: 550 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 1559 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 134 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

117 
WFUS51 KPHI 230140
TORPHI
PAC011-029-091-230200-
/O.NEW.KPHI.TO.W.0013.170823T0140Z-170823T0200Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
940 PM EDT TUE AUG 22 2017

The National Weather Service in Mount Holly NJ has issued a

* Tornado Warning for...
  Southeastern Berks County in eastern Pennsylvania...
  West central Montgomery County in southeastern Pennsylvania...
  North central Chester County in southeastern Pennsylvania...

* Until 1000 PM EDT
    
* At 939 PM EDT, a severe thunderstorm capable of producing a tornado
  was located near New Morgan, or 7 miles south of Reading, moving
  east at 55 mph.

  HAZARD...Tornado. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* This dangerous storm will be near...
  Birdsboro around 950 PM EDT. 
  Pottstown and Cedarville around 955 PM EDT. 
  Gilbertsville around 1000 PM EDT. 

Other locations impacted by this tornadic thunderstorm include Amity
Gardens, Stowe, Sanatoga, Pottsgrove, Kenilworth, South Pottstown and
Halfway House.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4025 7597 4033 7558 4020 7555 4018 7595
      4021 7598
TIME...MOT...LOC 0139Z 261DEG 49KT 4022 7594 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

MWG

1 follow-up statement

969 
WWUS51 KPHI 230157
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
957 PM EDT TUE AUG 22 2017

PAC011-029-091-230206-
/O.EXP.KPHI.TO.W.0013.000000T0000Z-170823T0200Z/
Berks PA-Montgomery PA-Chester PA-
957 PM EDT TUE AUG 22 2017

...THE TORNADO WARNING FOR SOUTHEASTERN BERKS...WEST CENTRAL
MONTGOMERY AND NORTH CENTRAL CHESTER COUNTIES WILL EXPIRE AT 1000 PM
EDT...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area.  

A severe thunderstorm watch remains in effect until midnight EDT for
eastern and southeastern Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
in Mount Holly NJ.


LAT...LON 4025 7597 4033 7558 4020 7555 4018 7595
      4021 7598
TIME...MOT...LOC 0156Z 261DEG 49KT 4026 7565 

$$

MWG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 8:12 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	48 min
Aug 22, 8:15 PM EDT	Tornado Warning	PHI	Monroe, Northampton	30 min
Aug 22, 8:45 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more	60 min
Aug 22, 8:58 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	24 min
Aug 22, 9:18 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	4 hr
Aug 22, 9:23 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	52 min
Aug 22, 9:42 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	48 min
Aug 22, 10:07 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia	53 min
Aug 22, 10:27 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	48 min
Aug 22, 10:37 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	4 hr
Aug 22, 10:40 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Aug 22, 10:58 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	62 min
Aug 22, 11:46 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	44 min
Aug 23, 12:06 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr
Aug 23, 12:29 AM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	46 min
Aug 23, 4:02 AM EDT	Areal Flood Warning	PHI	Chester, Delaware, Philadelphia	4 hr

Nearby

Tornado Warnings in Pennsylvania, 2017 Every tornado warning in 2017 Tornadoes in 2017

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.