Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 314, NWS Philadelphia/Mount Holly

September 7, 20234 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 7, 2023, 6:24 PM EDT for 4 counties in Pennsylvania. It was in force for 24 min. 1 report 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
Sep 7, 2023, 6:24 PM EDT (22:24 UTC)
Expired
Sep 7, 2023, 6:48 PM EDT
In force
24 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

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

The radar

The Philadelphia radar (KDIX), 114 km from the middle of the area, began a volume at 22:24 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
Sep 7, 6:24 PM EDTTSTM WND DMG1 Nnw Upper Milford Twp, PADowned trees on wires on MAIN RD, BRUNNER RD, VERA CRUZ RD, and ST PETERS RD. Time estimated from radar.

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

The watch it was issued in

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

IssuedProductOfficeLasted
Sep 7, 1:14 PM EDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.4 hours before the alert went out and 209 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, Brookhaven, NY at 12:00Z on 2023-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2039 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, Brookhaven, NY at 12:00Z on 2023-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 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
2039 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
1218 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

697 
WUUS51 KPHI 072224
SVRPHI
PAC017-077-089-095-072315-
/O.NEW.KPHI.SV.W.0314.230907T2224Z-230907T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
624 PM EDT Thu Sep 7 2023

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Lehigh County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  South central Monroe County in northeastern Pennsylvania...
  Northampton County in eastern Pennsylvania...

* Until 715 PM EDT.

* At 624 PM EDT, a severe thunderstorm was located over Ancient Oaks,
  or 7 miles southwest of Allentown, moving northeast at 35 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, Emmaus, Northampton,
  Quakertown, Wilson, Hellertown, Nazareth, Slatington, Bath,
  Walnutport, Belfast, West Easton, Tatamy, Riegelsville, Steuben,
  Glendon and Pleasant Valley.

This includes the following highways...
 Northeast Extension between mile markers 42 and 67.
 Interstate 78 in Pennsylvania between mile markers 45 and 76.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Mount Holly NJ.

&&

LAT...LON 4071 7519 4068 7520 4068 7517 4065 7520
      4057 7519 4056 7516 4039 7543 4060 7577
      4081 7553 4082 7548 4084 7549 4091 7541
TIME...MOT...LOC 2224Z 227DEG 31KT 4053 7558 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MPS
2 follow-up statements
064 
WWUS51 KPHI 072241
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
641 PM EDT Thu Sep 7 2023

PAC017-072251-
/O.CAN.KPHI.SV.W.0314.000000T0000Z-230907T2315Z/
Bucks PA-
641 PM EDT Thu Sep 7 2023

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN BUCKS 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 900 PM EDT for
eastern and northeastern Pennsylvania.

LAT...LON 4051 7542 4068 7568 4081 7553 4082 7548
      4084 7549 4091 7541 4072 7520
TIME...MOT...LOC 2241Z 217DEG 31KT 4066 7550 

$$

PAC077-089-095-072315-
/O.CON.KPHI.SV.W.0314.000000T0000Z-230907T2315Z/
Lehigh PA-Monroe PA-Northampton PA-
641 PM EDT Thu Sep 7 2023

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR NORTHEASTERN LEHIGH...SOUTH CENTRAL MONROE AND CENTRAL
NORTHAMPTON COUNTIES...

At 641 PM EDT, a severe thunderstorm was located over Northampton, or
near Allentown, moving northeast at 35 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, Emmaus, Northampton, Wilson,
Hellertown, Nazareth, Slatington, Bath, Walnutport, Belfast, Tatamy,
Steuben, Kunkletown, Neffs, Coffeetown, Rossland and Berlinsville.

This includes the following highways...
 Northeast Extension between mile markers 59 and 67.
 Interstate 78 in Pennsylvania between mile markers 58 and 67.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

&&

LAT...LON 4051 7542 4068 7568 4081 7553 4082 7548
      4084 7549 4091 7541 4072 7520
TIME...MOT...LOC 2241Z 217DEG 31KT 4066 7550 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

MPS
653 
WWUS51 KPHI 072248
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
648 PM EDT Thu Sep 7 2023

PAC077-089-095-072258-
/O.CAN.KPHI.SV.W.0314.000000T0000Z-230907T2315Z/
Lehigh PA-Monroe PA-Northampton PA-
648 PM EDT Thu Sep 7 2023

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN LEHIGH...SOUTH
CENTRAL MONROE AND CENTRAL NORTHAMPTON COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
eastern and northeastern Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 4051 7542 4068 7568 4081 7553 4082 7548
      4084 7549 4091 7541 4072 7520
TIME...MOT...LOC 2245Z 227DEG 31KT 4070 7544 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 1:10 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh33 min
Sep 7, 1:38 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh19 min
Sep 7, 2:10 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton50 min
Sep 7, 2:13 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh47 min
Sep 7, 2:52 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton24 min
Sep 7, 4:35 PM EDTSpecial Weather StatementPHIBerks25 min
Sep 7, 4:47 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh43 min
Sep 7, 5:17 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe43 min
Sep 7, 5:30 PM EDTSevere Thunderstorm WarningPHIBerks, Chester31 min
Sep 7, 5:34 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton41 min
Sep 7, 5:44 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Lehigh, Montgomery, Northampton46 min
Sep 7, 5:48 PM EDTSevere Thunderstorm WarningPHIChester42 min
Sep 7, 5:57 PM EDTSevere Thunderstorm WarningPHILehigh, Monroe, Northampton34 min
Sep 7, 6:06 PM EDTSpecial Weather StatementPHIBucks, Montgomery24 min
Sep 7, 6:18 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery42 min
Sep 7, 7:00 PM EDTSpecial Weather StatementPHIMontgomery30 min
Sep 7, 7:36 PM EDTSevere Thunderstorm WarningPHIBerks, Chester39 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2023Every severe thunderstorm warning in 2023

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.