Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 47, NWS Philadelphia/Mount Holly

July 3, 20184 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 3, 2018, 7:22 PM EDT for 4 counties in Pennsylvania. It was in force for 21 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 3, 2018, 7:22 PM EDT (23:22 UTC)
Expired
Jul 3, 2018, 7:43 PM EDT
In force
21 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

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

What was reported inside it

TimeReportWhereRemark
Jul 3, 7:25 PM EDTTSTM WND DMG1 Ene Frog Hollow Estat, PATWO LARGE TREES DOWN IN WORCESTER TWP. TIME ESTIMATED FROM RADAR.
Jul 3, 7:27 PM EDTTSTM WND DMGDevon, PATREE DOWN ON OLD LANCASTER ROAD BETWEEN FRANCIS AVENUE AND LAKESIDE AVENUE, FORCING ITS CLOSURE. TIME ESTIMATED FROM RADAR.

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, 11.4 hours before the alert went out and 203 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2018-07-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 574 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2018-07-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
574 J/kg
Mixed-layer CIN
-189 J/kg
Mixed-layer LCL
1257 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

637 
WUUS51 KPHI 032322
SVRPHI
PAC029-045-091-101-040000-
/O.NEW.KPHI.SV.W.0047.180703T2322Z-180704T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
722 PM EDT TUE JUL 3 2018

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southwestern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  West central Philadelphia County in southeastern Pennsylvania...
  Central Delaware County in southeastern Pennsylvania...

* Until 800 PM EDT.

* At 722 PM EDT, severe thunderstorms were located along a line
  extending from near Phoenixville to near Newtown Square, moving
  northwest at 10 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Philadelphia, Norristown, Phoenixville, West Norriton, East
  Norriton, Conshohocken, Collegeville, Royersford, Narberth, Trappe,
  Schwenksville, Morris Park, Pughtown, Bryn Mawr, Trout Lake, Radnor
  Township, Gradyville, Broomall, Newtown Square and Roxborough.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4012 7583 3988 7542 4002 7518 4026 7544
TIME...MOT...LOC 2322Z 119DEG 9KT 4014 7558 3997 7543 

HAIL...1.00IN
WIND...60MPH
 
$$

SFJ
1 follow-up statement
771 
WWUS51 KPHI 032343
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
743 PM EDT TUE JUL 3 2018

PAC029-045-091-101-032353-
/O.CAN.KPHI.SV.W.0047.000000T0000Z-180704T0000Z/
Montgomery PA-Chester PA-Philadelphia PA-Delaware PA-
743 PM EDT TUE JUL 3 2018

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN MONTGOMERY...
NORTHEASTERN CHESTER...WEST CENTRAL PHILADELPHIA AND CENTRAL DELAWARE
COUNTIES IS CANCELLED...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been cancelled.  However heavy rain is
still possible with these thunderstorms.

LAT...LON 4012 7583 3988 7542 4002 7518 4026 7544
TIME...MOT...LOC 2341Z 119DEG 9KT 4016 7563 3999 7548 

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 3, 2:15 PM EDTSpecial Weather StatementPHIDelaware30 min
Jul 3, 3:00 PM EDTSpecial Weather StatementPHIPhiladelphia60 min
Jul 3, 3:11 PM EDTFlash Flood WarningPHIMontgomery, Philadelphia50 min
Jul 3, 4:06 PM EDTSpecial Weather StatementPHIMontgomery54 min
Jul 3, 4:30 PM EDTSpecial Weather StatementPHIBucks60 min
Jul 3, 5:24 PM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia4 hr
Jul 3, 5:29 PM EDTAreal Flood AdvisoryPHIBucks, Montgomery, Philadelphia4 hr
Jul 3, 5:30 PM EDTSpecial Weather StatementPHIPhiladelphia30 min
Jul 3, 5:45 PM EDTFlash Flood WarningPHIDelaware, Montgomery, Philadelphia4 hr
Jul 3, 6:03 PM EDTSpecial Weather StatementPHIMonroe57 min
Jul 3, 6:15 PM EDTSpecial Weather StatementPHIChester60 min
Jul 3, 6:18 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia42 min
Jul 3, 6:21 PM EDTSpecial Weather StatementPHIDelaware24 min
Jul 3, 6:25 PM EDTSevere Thunderstorm WarningPHIBucks, Philadelphia50 min
Jul 3, 6:37 PM EDTFlash Flood WarningPHIBucks, Philadelphia3 hr
Jul 3, 6:40 PM EDTAreal Flood AdvisoryPHIChester, Delaware4 hr
Jul 3, 6:50 PM EDTSpecial Weather StatementPHIDelaware55 min
Jul 3, 6:54 PM EDTSevere Thunderstorm WarningPHIChester, Delaware51 min
Jul 3, 6:58 PM EDTFlash Flood WarningPHIChester, Delaware4 hr
Jul 3, 7:03 PM EDTSpecial Weather StatementPHINorthampton57 min
Jul 3, 7:06 PM EDTFlash Flood WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia2 hr
Jul 3, 7:35 PM EDTSpecial Weather StatementPHIChester25 min
Jul 3, 7:39 PM EDTSevere Thunderstorm WarningPHIChester51 min
Jul 3, 7:54 PM EDTFlash Flood WarningPHIChester4 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2018Every severe thunderstorm warning in 2018

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.