Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 19, NWS Philadelphia/Mount Holly

March 1, 20176 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Mar 1, 2017, 2:09 PM EST for 6 counties in Pennsylvania. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Mar 1, 2017, 2:09 PM EST (19:09 UTC)
Expired
Mar 1, 2017, 3:00 PM EST
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 139 km from the middle of the area, began a volume at 19:11 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Mar 1, 1:13 PM ESTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.2 hours before the alert went out and 99 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, Phillips Aaf/Abe, MD at 12:00Z on 2017-03-01Temperature 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, Phillips Aaf/Abe, MD at 12:00Z on 2017-03-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 square meters per square second.1939587897Sfc1 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
624 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
284 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

004 
WUUS51 KPHI 011909 RRA
SVRPHI
PAC011-017-029-077-091-095-012000-
/O.NEW.KPHI.SV.W.0019.170301T1909Z-170301T2000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
209 PM EST WED MAR 1 2017

The National Weather Service in Mount Holly NJ  has issued a

* Severe Thunderstorm Warning for...
  Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Northern Chester County in southeastern Pennsylvania...
  Southwestern Northampton County in eastern Pennsylvania...

* Until 300 PM EST

* At 209 PM EST, severe thunderstorms were located along a line
  extending from Strausstown to Columbia, moving east at 60 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

  IMPACT...Expect damage to roofs, siding, and trees. 

* Locations impacted include...
  Allentown, Reading, West Chester, Bethlehem, Pottstown,
  Phoenixville, Coatesville, Emmaus, Wyomissing, Northampton,
  Quakertown, Downingtown, Birdsboro, Collegeville, Kutztown,
  Royersford, Hamburg, Fleetwood, Sinking Spring and Laureldale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 4051 7636 4052 7625 4058 7605 4057 7602
      4062 7600 4076 7535 4025 7534 3993 7553
      4000 7597 4004 7593 4011 7594 4014 7588
      4046 7638
TIME...MOT...LOC 1909Z 254DEG 57KT 4052 7618 4006 7650 

HAIL...<.75IN
WIND...60MPH
 
$$

JRK
3 follow-up statements
488 
WWUS51 KPHI 011925
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
225 PM EST WED MAR 1 2017

PAC011-017-029-077-091-095-012000-
/O.CON.KPHI.SV.W.0019.000000T0000Z-170301T2000Z/
Berks PA-Montgomery PA-Lehigh PA-Bucks PA-Chester PA-Northampton PA-
225 PM EST WED MAR 1 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EST
FOR BERKS...NORTHWESTERN MONTGOMERY...LEHIGH...NORTHWESTERN BUCKS...
NORTHERN CHESTER AND SOUTHWESTERN NORTHAMPTON COUNTIES...

At 225 PM EST, severe thunderstorms were located along a line 
extending from Shoemakersville to near Reamstown, moving east at 60 
mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...Expect damage to roofs, siding, and trees. 

These severe storms will be near...
  Fleetwood, Shoemakersville and Lenhartsville around 230 PM EST. 
  Kutztown, Topton, Elverson, Lyons and New Morgan around 235 PM 
  EST. 
  Birdsboro and Claussville around 240 PM EST. 
  Allentown, Emmaus, Ancient Oaks, Cedarville, Coffeetown, 
  Zionsville and Pughtown around 245 PM EST. 
  Pottstown, Northampton, Royersford, Bechtelsville and 
  Gilbertsville around 250 PM EST. 
  Bethlehem, Collegeville, Trappe, Schwenksville, Bally, Steuben, 
  Lehigh University and Spring Mount around 255 PM EST. 
  East Greenville, Green Lane and Geryville around 300 PM EST. 

Other locations impacted by these severe thunderstorms include
Harleysville, West Lawn, Boyertown, West Reading, Pottsgrove, Lorane,
Kenhorst, Hokendauqua, South Pottstown and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 3999 7549 3998 7582 4000 7597 4004 7593
      4011 7594 4014 7588 4032 7616 4033 7616
      4051 7606 4063 7596 4076 7535 4025 7534
TIME...MOT...LOC 1925Z 255DEG 57KT 4050 7594 4018 7612 

HAIL...<.75IN
WIND...60MPH
 
$$

JRK
762 
WWUS51 KPHI 011943
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
243 PM EST WED MAR 1 2017

PAC029-011952-
/O.CAN.KPHI.SV.W.0019.000000T0000Z-170301T2000Z/
Chester PA-
243 PM EST WED MAR 1 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN CHESTER COUNTY IS
CANCELLED...

The storms which prompted the warning have weakened. Therefore, the 
warning has been cancelled.

A severe thunderstorm watch remains in effect until 700 PM EST for
eastern and southeastern Pennsylvania.

LAT...LON 4039 7534 4041 7579 4070 7564 4076 7535
TIME...MOT...LOC 1942Z 252DEG 56KT 4070 7558 4048 7570 

$$

PAC011-017-077-091-095-012000-
/O.CON.KPHI.SV.W.0019.000000T0000Z-170301T2000Z/
Berks PA-Montgomery PA-Lehigh PA-Bucks PA-Northampton PA-
243 PM EST WED MAR 1 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EST
FOR EAST CENTRAL BERKS...NORTHWESTERN MONTGOMERY...LEHIGH...
NORTHWESTERN BUCKS AND SOUTHWESTERN NORTHAMPTON COUNTIES...

At 242 PM EST, severe thunderstorms were located along a line
extending from Neffs to Topton, moving east at 60 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...Expect damage to roofs, siding, and trees. 

These severe storms will be near...
  Northampton, Bath and Steuben around 250 PM EST. 
  Allentown and Bethlehem around 255 PM EST. 
  Quakertown, Hellertown and Lehigh University around 300 PM EST. 

Other locations impacted by these severe thunderstorms include
Macungie, Coopersburg, North Catasauqua, Alburtis, Coplay,
Trumbauersville, Fountain Hill, Fullerton, Catasauqua and
Hokendauqua.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 4039 7534 4041 7579 4070 7564 4076 7535
TIME...MOT...LOC 1942Z 252DEG 56KT 4070 7558 4048 7570 

HAIL...<.75IN
WIND...60MPH
 
$$

JRK
971 
WWUS51 KPHI 011956
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
256 PM EST WED MAR 1 2017

PAC011-017-077-091-095-012006-
/O.EXP.KPHI.SV.W.0019.000000T0000Z-170301T2000Z/
Berks PA-Montgomery PA-Lehigh PA-Bucks PA-Northampton PA-
256 PM EST WED MAR 1 2017

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL BERKS...
NORTHWESTERN MONTGOMERY...LEHIGH...NORTHWESTERN BUCKS AND
SOUTHWESTERN NORTHAMPTON COUNTIES WILL EXPIRE AT 300 PM EST...
    
The storms which prompted the warning have weakened below severe
limits, and have exited the warned area. Therefore the warning will 
be allowed to expire.  However gusty winds to 45 mph are still 
possible with these showers.

A severe thunderstorm watch remains in effect until 700 PM EST for
eastern and southeastern Pennsylvania.

LAT...LON 4039 7534 4041 7579 4070 7564 4076 7535
TIME...MOT...LOC 1956Z 254DEG 57KT 4076 7532 4054 7544 

$$

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 1, 2:00 PM ESTSevere Thunderstorm WarningPHIChester, Delaware45 min
Mar 1, 2:02 PM ESTSpecial Weather StatementPHIBerks, Chester, Lehigh43 min
Mar 1, 2:31 PM ESTSpecial Weather StatementPHINorthampton29 min
Mar 1, 2:46 PM ESTSpecial Weather StatementPHIDelaware, Philadelphia29 min
Mar 1, 2:55 PM ESTSpecial Weather StatementPHIBucks, Montgomery, Northampton35 min
Mar 1, 3:09 PM ESTWind AdvisoryPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more19 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.