Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 140, NWS Philadelphia/Mount Holly

August 2, 20174 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 2, 2017, 1:30 PM EDT for 4 counties in Pennsylvania. It was in force for 30 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: Aug 2, 2017, 1:30 PM EDT (17:30 UTC)
Expired: Aug 2, 2017, 2:00 PM EDT
In force: 30 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 81 km from the middle of the area, began a volume at 17:31 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 2, 1:30 PM EDT	HAIL 0.88	King Of Prussia, PA	NICKEL-SIZED HAIL.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 215 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: 378 J/kg
Mixed-layer CIN: -76 J/kg
Mixed-layer LCL: 1469 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

311 
WUUS51 KPHI 021730
SVRPHI
PAC029-045-091-101-021800-
/O.NEW.KPHI.SV.W.0140.170802T1730Z-170802T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
130 PM EDT WED AUG 2 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 200 PM EDT

* At 130 PM EDT, a severe thunderstorm was located over King Of
  Prussia, or 14 miles northwest of Philadelphia, moving northeast at
  15 mph.

  HAZARD...Quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Minor damage to vehicles is possible. 

* Locations impacted include...
  Philadelphia, Norristown, West Norriton, East Norriton,
  Conshohocken, Ambler, Bryn Mawr, Trout Lake, Radnor Township,
  Valley Forge, Broomall, Plymouth Meeting, Paoli, Newtown Square,
  Chestnut Hill, King Of Prussia, Willow Grove, Skippack, Bridgeport
  and Malvern.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3996 7536 4002 7551 4023 7541 4015 7511
TIME...MOT...LOC 1730Z 204DEG 15KT 4009 7538 

HAIL...1.00IN
WIND...<50MPH
 
$$

po

1 follow-up statement

381 
WWUS51 KPHI 021743
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
143 PM EDT WED AUG 2 2017

PAC029-045-101-021752-
/O.CAN.KPHI.SV.W.0140.000000T0000Z-170802T1800Z/
Chester PA-Philadelphia PA-Delaware PA-
143 PM EDT WED AUG 2 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER...
NORTHWESTERN PHILADELPHIA AND NORTHEASTERN DELAWARE COUNTIES IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has weakened.

LAT...LON 4022 7539 4015 7513 4009 7521 4009 7522
      4001 7530 4003 7533 4007 7536 4006 7538
      4012 7546
TIME...MOT...LOC 1742Z 204DEG 15KT 4014 7535 

$$

PAC091-021800-
/O.CON.KPHI.SV.W.0140.000000T0000Z-170802T1800Z/
Montgomery PA-
143 PM EDT WED AUG 2 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR SOUTHEASTERN MONTGOMERY COUNTY...

At 142 PM EDT, a severe thunderstorm was located over East Norriton,
or 14 miles northwest of Philadelphia, moving northeast at 15 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Minor damage to vehicles is possible. 

Locations impacted include...
Norristown, West Norriton, East Norriton, Conshohocken, Ambler,
Plymouth Meeting, Bryn Mawr, King Of Prussia, Willow Grove, Skippack,
Bridgeport, West Conshohocken, Audubon, Fort Washington, Blue Bell,
Eagleville, Flourtown, Oreland, Trooper and Spring House.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4022 7539 4015 7513 4009 7521 4009 7522
      4001 7530 4003 7533 4007 7536 4006 7538
      4012 7546
TIME...MOT...LOC 1742Z 204DEG 15KT 4014 7535 

HAIL...1.00IN
WIND...<50MPH
 
$$

po

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 2, 12:09 PM EDT	Special Weather Statement	PHI	Philadelphia	36 min
Aug 2, 12:11 PM EDT	Special Weather Statement	PHI	Monroe	34 min
Aug 2, 12:28 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Aug 2, 12:39 PM EDT	Areal Flood Advisory	PHI	Monroe	4 hr
Aug 2, 12:45 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	4 hr
Aug 2, 12:52 PM EDT	Special Weather Statement	PHI	Monroe	23 min
Aug 2, 12:53 PM EDT	Special Weather Statement	PHI	Carbon	37 min
Aug 2, 12:55 PM EDT	Special Weather Statement	PHI	Delaware	35 min
Aug 2, 1:08 PM EDT	Special Weather Statement	PHI	Philadelphia	37 min
Aug 2, 1:26 PM EDT	Special Weather Statement	PHI	Delaware	34 min
Aug 2, 1:36 PM EDT	Special Weather Statement	PHI	Bucks	39 min
Aug 2, 1:48 PM EDT	Flash Flood Warning	PHI	Montgomery	4 hr
Aug 2, 1:49 PM EDT	Special Weather Statement	PHI	Lehigh	41 min
Aug 2, 1:50 PM EDT	Special Weather Statement	PHI	Philadelphia	25 min
Aug 2, 2:01 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Aug 2, 2:04 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	41 min
Aug 2, 2:09 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Montgomery	51 min
Aug 2, 2:16 PM EDT	Areal Flood Advisory	PHI	Berks	4 hr
Aug 2, 2:27 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Montgomery	4 hr
Aug 2, 2:37 PM EDT	Special Weather Statement	PHI	Berks	38 min
Aug 2, 2:45 PM EDT	Areal Flood Advisory	PHI	Monroe, Northampton	4 hr
Aug 2, 2:48 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	27 min
Aug 2, 3:04 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh, Northampton	41 min
Aug 2, 3:12 PM EDT	Special Weather Statement	PHI	Montgomery	48 min
Aug 2, 3:34 PM EDT	Special Weather Statement	PHI	Chester	26 min
Aug 2, 4:09 PM EDT	Areal Flood Advisory	PHI	Monroe	4 hr
Aug 2, 4:23 PM EDT	Special Weather Statement	PHI	Monroe	37 min
Aug 2, 4:27 PM EDT	Areal Flood Advisory	PHI	Delaware, Philadelphia	4 hr
Aug 2, 4:40 PM EDT	Special Weather Statement	PHI	Philadelphia	50 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2017 Every severe thunderstorm warning 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.