Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 358, NWS Philadelphia/Mount Holly

August 18, 2019Bucks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 18, 2019, 5:38 PM EDT for Bucks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 52 min. 11 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: Aug 18, 2019, 5:38 PM EDT (21:38 UTC)
Expired: Aug 18, 2019, 6:30 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.5 in
Wind: 60.0 mph

Counties Bucks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 108 km from the middle of the area, began a volume at 21:38 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 18, 5:38 PM EDT	HAIL 0.7	Macungie, PA	PEA TO DIME SIZE HAIL. TIME ESTIMATED.
Aug 18, 5:40 PM EDT	HAIL 1	2 E North Whitehall Twp, PA	TIME ESTIMATED FROM RADAR.
Aug 18, 5:43 PM EDT	HAIL 1.5	Hokendauqua, PA	TIME ESTIMATED FROM RADAR.
Aug 18, 5:44 PM EDT	TSTM WND GST 41	North Whitehall Twp, PA
Aug 18, 5:45 PM EDT	TSTM WND DMG	Catasauqua, PA	TREES DOWN ON WIRES. POWER OUTAGES IN THE AREA. TIME ESTIMATED FROM RADAR.
Aug 18, 5:45 PM EDT	HAIL 0.88	North Whitehall Twp, PA	NICKEL SIZE HAIL FELL FOR ABOUT 10 MINS.
Aug 18, 5:47 PM EDT	HAIL 1	Coplay, PA	DIME TO QUARTER SIZED HAIL. TIME ESTIMATED FROM RADAR.
Aug 18, 5:47 PM EDT	HAIL 1.5	North Catasauqua, PA	QUARTER TO PING PONG BALL SIZED HAIL REPORTED IN NORTH CATASAUQUA. TIME ESTIMATED FROM RADAR.
Aug 18, 5:50 PM EDT	HAIL 1.25	Northampton, PA	TIME ESTIMATED.
Aug 18, 5:53 PM EDT	TSTM WND GST 53	Lehigh Valley Internati, PA
Aug 18, 6:00 PM EDT	HAIL 1.25	Northampton, PA

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 9.6 hours before the alert went out and 208 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: 1275 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 622 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

As transmitted.

928 
WUUS51 KPHI 182138
SVRPHI
PAC017-077-095-182230-
/O.NEW.KPHI.SV.W.0358.190818T2138Z-190818T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
538 PM EDT Sun Aug 18 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Eastern Lehigh County in eastern Pennsylvania...
  North central Bucks County in southeastern Pennsylvania...
  Southwestern Northampton County in eastern Pennsylvania...

* Until 630 PM EDT.

* At 538 PM EDT, a severe thunderstorm was located over Coffeetown,
  or near Allentown, moving east at 15 mph.

  HAZARD...Ping pong ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Wind 
           damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Wilson,
  Hellertown, Nazareth, Wind Gap, Bath, Belfast, West Easton, Tatamy,
  Riegelsville, Steuben, Glendon, Coffeetown, Ancient Oaks and Lehigh
  University.

This includes Interstate 78 in Pennsylvania between mile markers 51
and 76.
 
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 this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4062 7519 4062 7520 4059 7519 4057 7519
      4056 7517 4055 7516 4050 7560 4057 7564
      4069 7560 4087 7530 4086 7529
TIME...MOT...LOC 2138Z 254DEG 11KT 4065 7553 

HAIL...1.50IN
WIND...60MPH
 
$$

Staarmann

1 follow-up statement

557 
WWUS51 KPHI 182205
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
605 PM EDT Sun Aug 18 2019

PAC017-077-095-182230-
/O.CON.KPHI.SV.W.0358.000000T0000Z-190818T2230Z/
Lehigh PA-Bucks PA-Northampton PA-
605 PM EDT Sun Aug 18 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR NORTHEASTERN LEHIGH...NORTH CENTRAL BUCKS AND CENTRAL NORTHAMPTON
COUNTIES...

At 605 PM EDT, a severe thunderstorm was located over Bath, or 9
miles northeast of Allentown, moving northeast at 15 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Wind damage 
         to roofs, siding, trees, and power lines is possible.

Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Northampton, Wilson, Hellertown,
Nazareth, Wind Gap, Bath, Belfast, West Easton, Tatamy, Riegelsville,
Steuben, Glendon, Lehigh University, Beersville, Old Orchard and
Catasauqua.

This includes Interstate 78 in Pennsylvania between mile markers 64
and 76.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.

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

&&

LAT...LON 4062 7519 4062 7520 4059 7519 4057 7519
      4056 7517 4055 7516 4058 7546 4065 7547
      4072 7553 4087 7530 4086 7529
TIME...MOT...LOC 2205Z 243DEG 13KT 4071 7540 

HAIL...1.50IN
WIND...60MPH
 
$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 8:32 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	73 min
Aug 18, 3:32 AM EDT	Heat Advisory	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	4 days
Aug 18, 4:22 PM EDT	Special Weather Statement	PHI	Berks	38 min
Aug 18, 4:34 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Montgomery	41 min
Aug 18, 4:36 PM EDT	Special Weather Statement	PHI	Bucks	24 min
Aug 18, 5:01 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	3 hr
Aug 18, 5:16 PM EDT	Special Weather Statement	PHI	Berks	29 min
Aug 18, 5:25 PM EDT	Special Weather Statement	PHI	Carbon, Monroe, Northampton	65 min
Aug 18, 5:29 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	2 hr
Aug 18, 5:36 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	39 min
Aug 18, 5:42 PM EDT	Special Weather Statement	PHI	Berks	48 min
Aug 18, 6:28 PM EDT	Special Weather Statement	PHI	Northampton	47 min
Aug 18, 6:40 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	54 min
Aug 18, 7:03 PM EDT	Special Weather Statement	PHI	Berks	27 min
Aug 18, 7:23 PM EDT	Special Weather Statement	PHI	Berks	67 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019 Every 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.