Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 7, NWS Philadelphia/Mount Holly

April 21, 2021Warren County, New Jersey; Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 21, 2021, 12:25 PM EDT for Warren County, New Jersey; Lehigh County, Northampton County, Pennsylvania. It was in force for 50 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: Apr 21, 2021, 12:25 PM EDT (16:25 UTC)
Expired: Apr 21, 2021, 1:15 PM EDT
In force: 50 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Warren County, NJ, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 115 km from the middle of the area, began a volume at 16:27 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
Apr 21, 12:27 PM EDT	HAIL 0.25	1 Ne Eastlawn Gardens, PA
Apr 21, 12:35 PM EDT	TSTM WND DMG	1 Ssw Allentown, PA	TREE DOWN ON WIRES NEAR LEHIGH PKWY. TIME ESTIMATED FROM RADAR.
Apr 21, 12:35 PM EDT	HAIL 0.25	Tatamy, PA	PEA SIZE HAIL REPORTED BY A TRAINED SPOTTER IN TATAMY, PA. TIME ESTIMATED BY RADAR.
Apr 21, 12:40 PM EDT	HAIL 0.25	1 Wsw Bethlehem Twp, PA
Apr 21, 12:40 PM EDT	HAIL 0.5	2 Ene Bethlehem Twp, PA
Apr 21, 12:45 PM EDT	HAIL 0.25	Martins Creek, PA
Apr 21, 12:45 PM EDT	HAIL 0.88	2 Wnw Forks Twp, PA
Apr 21, 12:50 PM EDT	HAIL 0.25	2 Wsw Williams Twp, PA
Apr 21, 12:50 PM EDT	HAIL 0.25	Martins Creek, PA
Apr 21, 1:00 PM EDT	HAIL 0.7	1 W Easton, PA	DIME SIZE HAIL IN EASTON. TIME ESTIMATED FROM RADAR.
Apr 21, 1:05 PM EDT	TSTM WND GST 46	1 Ene Pohatcong Twp, NJ

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, 4.4 hours before the alert went out and 190 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1427 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 206 m²/s²
0-3 km storm-relative helicity: 201 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

790 
WUUS51 KPHI 211625
SVRPHI
NJC041-PAC077-095-211715-
/O.NEW.KPHI.SV.W.0007.210421T1625Z-210421T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1225 PM EDT Wed Apr 21 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Warren County in northwestern New Jersey...
  East central Lehigh County in eastern Pennsylvania...
  Northampton County in eastern Pennsylvania...

* Until 115 PM EDT.

* At 1225 PM EDT, a severe thunderstorm was located over Nazareth, or
  near Easton, moving east at 40 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...
  Allentown, Easton, Bethlehem, Forks, Wilson, Washington,
  Blairstown, Nazareth, Bangor, Pen Argyl, Wind Gap, Bath, Belvidere,
  Harmony, Oxford, Alpha, Hope, Belfast, Hampton and West Easton.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 71 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 7.
 Interstate 80 in New Jersey between mile markers 3 and 16.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4103 7489 4080 7486 4078 7490 4071 7497
      4066 7508 4057 7550 4073 7544 4086 7529
      4090 7523 4091 7524 4092 7522
TIME...MOT...LOC 1625Z 247DEG 35KT 4074 7530 

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

Davis

2 follow-up statements

041 
WWUS51 KPHI 211702
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
102 PM EDT Wed Apr 21 2021

PAC077-211712-
/O.CAN.KPHI.SV.W.0007.000000T0000Z-210421T1715Z/
Lehigh PA-
102 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL LEHIGH COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 600 PM EDT for
northern and northwestern New Jersey...and eastern Pennsylvania.

LAT...LON 4103 7489 4080 7486 4078 7490 4071 7497
      4066 7508 4063 7525 4095 7514
TIME...MOT...LOC 1702Z 247DEG 35KT 4088 7486 

$$

NJC041-PAC095-211715-
/O.CON.KPHI.SV.W.0007.000000T0000Z-210421T1715Z/
Warren NJ-Northampton PA-
102 PM EDT Wed Apr 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR WARREN AND EASTERN NORTHAMPTON COUNTIES...

At 102 PM EDT, a severe thunderstorm was located over Great
Meadows-Vienna, or 13 miles southwest of Newton, moving northeast at
40 mph.

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

SOURCE...Trained weather spotters.

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

Locations impacted include...
Easton, Washington, Blairstown, Belvidere, Harmony, Oxford, Alpha,
Hope, Hampton, West Easton, Bloomsbury, Glendon, Great
Meadows-Vienna, Brass Castle, Pleasant Valley, Roxburg, Columbia,
Beatyestown, Phillipsburg and Portland.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 75 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 7.
 Interstate 80 in New Jersey between mile markers 3 and 16.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4103 7489 4080 7486 4078 7490 4071 7497
      4066 7508 4063 7525 4095 7514
TIME...MOT...LOC 1702Z 247DEG 35KT 4088 7486 

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

Davis

659 
WWUS51 KPHI 211711
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
111 PM EDT Wed Apr 21 2021

NJC041-PAC095-211721-
/O.EXP.KPHI.SV.W.0007.000000T0000Z-210421T1715Z/
Warren NJ-Northampton PA-
111 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR WARREN AND EASTERN NORTHAMPTON
COUNTIES WILL EXPIRE AT 115 PM EDT...
    
The severe thunderstorm which prompted the warning has weakened.
Therefore, the warning will be allowed to expire.  However small 
hail and gusty winds are still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 600 PM EDT for
northern and northwestern New Jersey...and eastern Pennsylvania.

LAT...LON 4103 7489 4080 7486 4078 7490 4071 7497
      4066 7508 4063 7525 4095 7514
TIME...MOT...LOC 1711Z 247DEG 35KT 4091 7478 

$$

Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 8:48 PM EDT	Freeze Watch	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	7 hr
Apr 21, 3:26 AM EDT	Freeze Warning	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	30 hr
Apr 21, 12:51 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	21 min
Apr 21, 12:55 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	27 min
Apr 21, 1:10 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Mercer, Salem	50 min
Apr 21, 1:17 PM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset, Sussex	58 min
Apr 21, 1:28 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester	36 min
Apr 21, 1:30 PM EDT	Special Marine Warning	PHI		60 min
Apr 21, 1:43 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset	33 min
Apr 21, 1:58 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Monmouth, Ocean	62 min
Apr 21, 2:02 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Monmouth, Ocean	43 min
Apr 21, 2:03 PM EDT	Special Weather Statement	PHI	Cumberland	27 min
Apr 21, 2:17 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cumberland, Gloucester, Salem	43 min
Apr 21, 2:28 PM EDT	Special Weather Statement	PHI	Middlesex, Monmouth	47 min
Apr 21, 2:30 PM EDT	Special Marine Warning	PHI		60 min
Apr 21, 2:38 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	37 min
Apr 21, 2:40 PM EDT	Special Marine Warning	PHI		55 min
Apr 21, 2:43 PM EDT	Special Weather Statement	PHI	Cape May	32 min
Apr 21, 2:50 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	40 min
Apr 21, 3:02 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic	28 min
Apr 21, 3:07 PM EDT	Special Marine Warning	PHI		53 min
Apr 21, 12:03 PM EDT	Special Weather Statement	PHI	Chester, Lehigh	42 min
Apr 21, 12:17 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	43 min
Apr 21, 12:54 PM EDT	Special Weather Statement	PHI	Delaware	36 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021 Severe Thunderstorm Warnings in New Jersey, 2021 Every severe thunderstorm warning in 2021

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.