Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017
Severe Thunderstorm Warning 59, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 21, 2017, 4:02 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania. It was in force for 43 min. 7 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
- Jun 21, 2017, 4:02 PM EDT (20:02 UTC)
- Expired
- Jun 21, 2017, 4:45 PM EDT
- In force
- 43 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Bucks County, PA, Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 97 km from the middle of the area, began a volume at 20:03 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 |
|---|---|---|---|
| Jun 21, 4:03 PM EDT | TSTM WND DMG | Pottstown, PA | SEVERAL TREES AND WIRES DOWN |
| Jun 21, 4:12 PM EDT | TSTM WND DMG | 2 W Green Lane, PA | TRESS AND WIRES DOWN... TIME ESTIMATED |
| Jun 21, 4:14 PM EDT | TSTM WND DMG | Franconia, PA | TWO LARGE LIMBS DOWN... TIME ESTIMATED |
| Jun 21, 4:14 PM EDT | TSTM WND DMG | Upper Providence Twp, PA | SEVERAL TREES AND WIRES BLOWN DOWN. |
| Jun 21, 4:26 PM EDT | TSTM WND DMG | Norristown, PA | LARGE BRANCHES DOWN... TIME ESTIMATED |
| Jun 21, 4:33 PM EDT | TSTM WND GST 72 | 3 N Conshohocken, PA | TIME ESTIMATED |
| Jun 21, 4:42 PM EDT | TSTM WND DMG | Warminster Heights, PA | LARGE TREE LIMBS DOWN |
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, 8.0 hours before the alert went out and 210 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.
- Mixed-layer CAPE
- 31 J/kg
- Mixed-layer CIN
- -95 J/kg
- Mixed-layer LCL
- 1812 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- -27 m²/s²
- 0-3 km storm-relative helicity
- 56 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
705
WUUS51 KPHI 212002
SVRPHI
PAC017-029-091-212045-
/O.NEW.KPHI.SV.W.0059.170621T2002Z-170621T2045Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
402 PM EDT WED JUN 21 2017
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Montgomery County in southeastern Pennsylvania...
Southwestern Bucks County in southeastern Pennsylvania...
Northeastern Chester County in southeastern Pennsylvania...
* Until 445 PM EDT
* At 402 PM EDT, severe thunderstorms were located along a line
extending from near East Greenville to near Gilbertsville to near
Elverson, moving east at 35 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to trees and power lines.
* Locations impacted include...
Norristown, Pottstown, Phoenixville, Lansdale, West Norriton, East
Norriton, Conshohocken, Hatboro, Souderton, Ambler, Collegeville,
Royersford, Chalfont, Trappe, Hatfield, East Greenville,
Schwenksville, Bryn Athyn, Elverson and Ivyland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4022 7575 4025 7569 4030 7565 4043 7552
4018 7500 4005 7534 4006 7536 4004 7541
4003 7540 4001 7545 4014 7584
TIME...MOT...LOC 2002Z 286DEG 32KT 4037 7549 4029 7555 4015 7576
HAIL...<.75IN
WIND...60MPH
$$
JRK3 follow-up statements
873
WWUS51 KPHI 212015
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
415 PM EDT WED JUN 21 2017
PAC017-029-091-212045-
/O.CON.KPHI.SV.W.0059.000000T0000Z-170621T2045Z/
Montgomery PA-Bucks PA-Chester PA-
415 PM EDT WED JUN 21 2017
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR MONTGOMERY...SOUTHWESTERN BUCKS AND NORTHEASTERN CHESTER
COUNTIES...
At 414 PM EDT, severe thunderstorms were located along a line
extending from near Souderton to near Schwenksville to Chester
Springs, moving east at 35 mph.
HAZARD...60 mph wind gusts.
SOURCE...Local fire department and trained weather spotter reported
several trees and wires down in Pottstown from the severe
thunderstorm that moved through just after 4 PM.
IMPACT...Expect damage to trees and power lines.
Locations impacted include...
Norristown, Phoenixville, Lansdale, West Norriton, East Norriton,
Conshohocken, Hatboro, Souderton, Ambler, Collegeville, Royersford,
Chalfont, Trappe, Hatfield, Schwenksville, Bryn Athyn, Ivyland,
Pughtown, Spring Mount and King Of Prussia.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4011 7575 4028 7551 4038 7541 4018 7500
4005 7534 4006 7536 4004 7541 4003 7540
4001 7545
TIME...MOT...LOC 2014Z 286DEG 32KT 4034 7535 4026 7542 4012 7563
HAIL...<.75IN
WIND...60MPH
$$
JRK860
WWUS51 KPHI 212033
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
433 PM EDT WED JUN 21 2017
PAC017-029-091-212045-
/O.CON.KPHI.SV.W.0059.000000T0000Z-170621T2045Z/
Montgomery PA-Bucks PA-Chester PA-
433 PM EDT WED JUN 21 2017
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR SOUTHEASTERN MONTGOMERY...SOUTH CENTRAL BUCKS AND NORTHEASTERN
CHESTER COUNTIES...
At 432 PM EDT, severe thunderstorms were located along a line
extending from near Lansdale to Ambler to Radnor Township, moving
southeast at 40 mph.
HAZARD...60 mph wind gusts.
SOURCE...Trained weather spotters. Numerous downed trees and wires
have been reported across Montgomery County in the past
half hour.
IMPACT...Expect damage to trees and power lines.
Locations impacted include...
Norristown, Lansdale, West Norriton, East Norriton, Conshohocken,
Hatboro, Ambler, Chalfont, Bryn Athyn, Ivyland, Willow Grove,
Plymouth Meeting, King Of Prussia, Radnor Township, Horsham,
Bridgeport, North Wales, West Conshohocken, Fort Washington and Blue
Bell.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4002 7549 4018 7532 4029 7522 4018 7500
4005 7534 4006 7536 4004 7541 4003 7540
4001 7545
TIME...MOT...LOC 2032Z 293DEG 33KT 4025 7524 4017 7524 4003 7539
HAIL...<.75IN
WIND...60MPH
$$
JRK028
WWUS51 KPHI 212039
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
439 PM EDT WED JUN 21 2017
PAC017-029-091-212047-
/O.EXP.KPHI.SV.W.0059.000000T0000Z-170621T2045Z/
Montgomery PA-Bucks PA-Chester PA-
439 PM EDT WED JUN 21 2017
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MONTGOMERY...
SOUTH CENTRAL BUCKS AND NORTHEASTERN CHESTER COUNTIES WILL EXPIRE AT
445 PM EDT...
The storms which prompted the warning is moving out of the area.
Therefore the warning will be allowed to expire.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
in Mount Holly NJ.
Remember, a Severe Thunderstorm Warning still remains in effect
farther east across eastern Montgomery, southeastern lower Bucks and
northeastern Chester County until 515 PM.
LAT...LON 4002 7549 4018 7532 4029 7522 4018 7500
4005 7534 4006 7536 4004 7541 4003 7540
4001 7545
TIME...MOT...LOC 2037Z 286DEG 32KT 4024 7518 4016 7518 4002 7533
$$
JRKThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 2:32 PM EDT | Special Weather Statement | PHI | Carbon | 43 min |
| Jun 21, 3:32 PM EDT | Special Weather Statement | PHI | Carbon, Northampton | 28 min |
| Jun 21, 3:51 PM EDT | Special Weather Statement | PHI | Montgomery | 39 min |
| Jun 21, 4:21 PM EDT | Special Weather Statement | PHI | Bucks | 39 min |
| Jun 21, 4:28 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 47 min |
| Jun 21, 5:28 PM EDT | Special Weather Statement | PHI | Chester, Delaware | 32 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2017Every 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.