Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 1, NWS Philadelphia/Mount Holly

March 15, 2019Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Mar 15, 2019, 7:09 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 51 min. 5 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
Mar 15, 2019, 7:09 PM EDT (23:09 UTC)
Expired
Mar 15, 2019, 8:00 PM EDT
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

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

The radar

The Philadelphia radar (KDIX), 126 km from the middle of the area, began a volume at 23:10 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

TimeReportWhereRemark
Mar 15, 7:30 PM EDTTSTM WND DMGPottstown, PAREPORTS OF SEVERAL TREES DOWN THROUGHOUT WESTERN PORTIONS OF MONTGOMERY COUNTY, MAINLY NEAR POTTSTOWN. SOME POWER LINES DOWN AS WELL.
Mar 15, 7:38 PM EDTTSTM WND DMGPottstown, PASOME TREES DOWN AND LOST POWER. UNKNOWN ESTIMATE OF WINDS.
Mar 15, 7:38 PM EDTHAIL 1Pottstown, PA
Mar 15, 7:40 PM EDTTSTM WND DMGPottstown, PAPHOTO SHOWS SPRUCE TREE OF ROUGHLY 2-3 FEET IN DIAMETER FALLEN ON HOME. NO SIGNIFICANT DAMAGE APPARENT THOUGH. TIME ESTIMATED FROM RADAR.
Mar 15, 7:41 PM EDTHAIL 0.75Pottstown, PA

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, 11.2 hours before the alert went out and 194 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 2019-03-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2019-03-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 379 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1006 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
379 m²/s²
0-3 km storm-relative helicity
410 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

123 
WUUS51 KPHI 152309
SVRPHI
PAC011-029-091-160000-
/O.NEW.KPHI.SV.W.0001.190315T2309Z-190316T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
709 PM EDT FRI MAR 15 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 800 PM EDT.

* At 708 PM EDT, a severe thunderstorm was located near New Morgan,
  or 8 miles south of Reading, moving east at 35 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Pottstown, Phoenixville, Birdsboro, Collegeville, Royersford,
  Trappe, Elverson, New Morgan, Pughtown, Gilbertsville, Cedarville,
  Stowe, Shillington, Boyertown, Spring City, Mohnton, Pottsgrove,
  Lorane, South Pottstown and Amity Gardens.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to 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.

&&

LAT...LON 4027 7606 4038 7554 4012 7545 4013 7590
      4014 7588 4025 7605
TIME...MOT...LOC 2308Z 264DEG 31KT 4022 7596 

HAIL...0.88IN
WIND...60MPH
 
$$

Gorse
1 follow-up statement
927 
WWUS51 KPHI 152335
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
735 PM EDT FRI MAR 15 2019

PAC011-029-091-160000-
/O.CON.KPHI.SV.W.0001.000000T0000Z-190316T0000Z/
Berks PA-Montgomery PA-Chester PA-
735 PM EDT FRI MAR 15 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SOUTHEASTERN BERKS...NORTHWESTERN MONTGOMERY AND NORTHEASTERN
CHESTER COUNTIES...

At 735 PM EDT, a severe thunderstorm was located over Pottstown, or
19 miles east of Reading, moving east at 45 mph.

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

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Pottstown, Phoenixville, Collegeville, Royersford, Trappe, Pughtown,
Gilbertsville, Cedarville, Stowe, Boyertown, Spring City, Pottsgrove,
South Pottstown, Amity Gardens, Sanatoga, Kenilworth and Halfway
House.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4038 7554 4012 7545 4013 7575 4034 7573
TIME...MOT...LOC 2335Z 263DEG 38KT 4025 7558 

HAIL...0.75IN
WIND...60MPH
 
$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 15, 6:02 PM EDTSpecial Weather StatementPHILehigh, Northampton28 min
Mar 15, 6:08 PM EDTSpecial Weather StatementPHIBerks37 min
Mar 15, 6:27 PM EDTSpecial Weather StatementPHINorthampton33 min
Mar 15, 6:33 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh, Northampton117 min
Mar 15, 7:23 PM EDTSevere Thunderstorm WarningPHIBucks52 min
Mar 15, 7:32 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Montgomery43 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019Every severe thunderstorm warning in 2019

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.