Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 73, NWS Philadelphia/Mount Holly

June 9, 2021Berks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 9, 2021, 5:27 PM EDT for Berks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 23 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
Jun 9, 2021, 5:27 PM EDT (21:27 UTC)
Expired
Jun 9, 2021, 5:50 PM EDT
In force
23 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Berks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 144 km from the middle of the area, began a volume at 21:28 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.5 hours before the alert went out and 227 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 2021-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 193 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -75 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
193 J/kg
Mixed-layer CIN
-128 J/kg
Mixed-layer LCL
1225 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-75 m²/s²
0-3 km storm-relative helicity
3 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

446 
WUUS51 KPHI 092127
SVRPHI
PAC011-077-095-092215-
/O.NEW.KPHI.SV.W.0073.210609T2127Z-210609T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
527 PM EDT Wed Jun 9 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northeastern Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Southwestern Northampton County in eastern Pennsylvania...

* Until 615 PM EDT.

* At 527 PM EDT, a severe thunderstorm was located over Hamburg, or
  12 miles east of Schuylkill Haven, moving northwest at 15 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...
  Allentown, Bethlehem, Emmaus, Northampton, Hellertown, Kutztown,
  Hamburg, Slatington, Fleetwood, Walnutport, Topton, Leesport,
  Shoemakersville, Lyons, Lenhartsville, Neffs, Coffeetown, New
  Tripoli, Berlinsville and Ancient Oaks.

This includes the following highways...
 Northeast Extension between mile markers 51 and 71.
 Interstate 78 in Pennsylvania between mile markers 22 and 71.

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 4056 7609 4058 7606 4057 7602 4065 7598
      4070 7583 4078 7567 4078 7562 4080 7556
      4062 7526 4037 7578 4046 7611 4053 7619
TIME...MOT...LOC 2127Z 144DEG 12KT 4057 7595 

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

Davis
1 follow-up statement
006 
WWUS51 KPHI 092150
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
550 PM EDT Wed Jun 9 2021

PAC011-077-095-092159-
/O.CAN.KPHI.SV.W.0073.000000T0000Z-210609T2215Z/
Berks PA-Lehigh PA-Northampton PA-
550 PM EDT Wed Jun 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BERKS...LEHIGH
AND SOUTHWESTERN NORTHAMPTON COUNTIES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has 
been cancelled.  However, small hail and gusty winds are still 
possible with this thunderstorm.

LAT...LON 4056 7609 4058 7606 4057 7602 4065 7598
      4070 7583 4078 7567 4078 7562 4080 7556
      4062 7526 4037 7578 4046 7611 4053 7619
TIME...MOT...LOC 2147Z 144DEG 12KT 4063 7601 

$$

Davis

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 3:49 PM EDTFlash Flood WarningPHIBucks, Philadelphia3 hr
Jun 9, 4:54 PM EDTFlash Flood WarningPHIBerks, Montgomery112 min
Jun 9, 5:32 PM EDTSevere Thunderstorm WarningPHIBucks28 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.