Alert archive / Pennsylvania / Tornado Warnings in 2021

Tornado Warning 30, NWS Philadelphia/Mount Holly

August 19, 2021Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this tornado warning at Aug 19, 2021, 12:26 AM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 34 min. 2 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 19, 2021, 12:26 AM EDT (04:26 UTC)
Expired
Aug 19, 2021, 1:00 AM EDT
In force
34 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 84 km from the middle of the area, began a volume at 04:25 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
Aug 19, 12:27 AM EDTTSTM WND DMG1 Ese Souderton, PADOWNED TREES AND WIRES AND SOME DAMAGE TO HOMES IN THE AREA OF DEERFIELD DRIVE AND TOWNSHIP LINE ROAD. TIME ESTIMATED FROM RADAR. POSSIBLE TORNADO DAMAGE.
Aug 19, 12:33 AM EDTTSTM WND DMG1 E Perkasie, PAWIRES DOWN NEAR PERKASIE. LIKELY TORNADO DAMAGE. TIME BASED ON RADAR AND APPARENT TORNADO DEBRIS SIGNATURE.

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 00:00Z, 4.4 hours before the alert went out and 213 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 00:00Z on 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 491 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 00:00Z on 2021-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 62 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
491 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
580 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

313 
WFUS51 KPHI 190426
TORPHI
PAC017-091-190500-
/O.NEW.KPHI.TO.W.0030.210819T0426Z-210819T0500Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
1226 AM EDT Thu Aug 19 2021

The National Weather Service in Mount Holly NJ has issued a

* Tornado Warning for...
  Central Montgomery County in southeastern Pennsylvania...
  West central Bucks County in southeastern Pennsylvania...

* Until 100 AM EDT.
    
* At 1226 AM EDT, a severe thunderstorm capable of producing a
  tornado was located over Hatfield, or 21 miles northwest of
  Philadelphia, moving northeast at 30 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Lansdale, Perkasie, Doylestown, Souderton, Bedminster, Chalfont,
  Hatfield, Dublin, Fricks, Gardenville, Telford, Sellersville, New
  Britain, Silverdale, Harleysville, Kulpsville and Montgomeryville.

This includes Northeast Extension between mile markers 29 and 35.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 4022 7534 4027 7544 4047 7524 4036 7505
TIME...MOT...LOC 0426Z 227DEG 25KT 4028 7532 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Meola
2 follow-up statements
822 
WWUS51 KPHI 190433
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1233 AM EDT Thu Aug 19 2021

PAC091-190442-
/O.CAN.KPHI.TO.W.0030.000000T0000Z-210819T0500Z/
Montgomery PA-
1233 AM EDT Thu Aug 19 2021

...THE TORNADO WARNING FOR CENTRAL MONTGOMERY COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

LAT...LON 4047 7524 4038 7509 4027 7524 4028 7525
      4034 7536 4035 7536
TIME...MOT...LOC 0432Z 218DEG 32KT 4033 7528 

$$

PAC017-190500-
/O.CON.KPHI.TO.W.0030.000000T0000Z-210819T0500Z/
Bucks PA-
1233 AM EDT Thu Aug 19 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 100 AM EDT FOR WEST
CENTRAL BUCKS COUNTY...
    
At 1232 AM EDT, a severe thunderstorm capable of producing a tornado
was located over Souderton, or 20 miles southeast of Allentown,
moving northeast at 35 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
Perkasie, Souderton, Bedminster, Chalfont, Dublin, Fricks,
Gardenville, Telford, Sellersville and Silverdale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 4047 7524 4038 7509 4027 7524 4028 7525
      4034 7536 4035 7536
TIME...MOT...LOC 0432Z 218DEG 32KT 4033 7528 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

Meola
579 
WWUS51 KPHI 190451
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1251 AM EDT Thu Aug 19 2021

PAC017-190501-
/O.EXP.KPHI.TO.W.0030.000000T0000Z-210819T0500Z/
Bucks PA-
1251 AM EDT Thu Aug 19 2021

...THE TORNADO WARNING FOR WEST CENTRAL BUCKS COUNTY WILL EXPIRE AT
100 AM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 4047 7524 4038 7509 4027 7524 4028 7525
      4034 7536 4035 7536
TIME...MOT...LOC 0451Z 227DEG 25KT 4041 7517 

$$

Meola

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 8:53 PM EDTAreal Flood AdvisoryPHIBerks3 hr
Aug 18, 9:10 PM EDTAreal Flood AdvisoryPHILehigh, Monroe, Northampton3 hr
Aug 18, 9:30 PM EDTFlash Flood WarningPHIBerks2 hr
Aug 18, 9:35 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh3 hr
Aug 18, 9:45 PM EDTAreal Flood AdvisoryPHIBerks3 hr
Aug 18, 9:47 PM EDTSpecial Weather StatementPHIBerks58 min
Aug 18, 10:16 PM EDTFlash Flood WarningPHIBerks, Lehigh3 hr
Aug 18, 10:44 PM EDTFlash Flood WarningPHILehigh, Monroe, Northampton4 hr
Aug 18, 10:50 PM EDTFlash Flood WarningPHIBucks, Chester, Montgomery4 hr
Aug 18, 11:19 PM EDTAreal Flood AdvisoryPHIBucks, Lehigh, Northampton3 hr
Aug 18, 11:19 PM EDTSpecial Weather StatementPHIBucks, Chester, Montgomery41 min
Aug 18, 11:47 PM EDTFlash Flood WarningPHIChester2 hr
Aug 19, 12:04 AM EDTSpecial Weather StatementPHIBucks, Delaware, Montgomery71 min
Aug 19, 12:31 AM EDTFlash Flood WarningPHIBucks, Chester, Delaware, Montgomery4 hr
Aug 19, 12:44 AM EDTRiver Flood WarningPHIChester5 hr
Aug 19, 12:47 AM EDTTornado WarningPHIChester, Delaware, Montgomery, Philadelphia28 min
Aug 19, 12:48 AM EDTTornado WarningPHIBucks27 min
Aug 19, 1:14 AM EDTSpecial Weather StatementPHIBucks, Delaware, Philadelphia91 min
Aug 19, 1:30 AM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Aug 19, 2:05 AM EDTAreal Flood AdvisoryPHIBucks3 hr
Aug 19, 2:13 AM EDTFlash Flood WarningPHIBucks, Philadelphia4 hr
Aug 19, 4:33 AM EDTAreal Flood WarningPHIChester, Delaware4 hr
Aug 19, 6:09 AM EDTAreal Flood WarningPHIBucks, Philadelphia3 hr
Aug 19, 8:50 AM EDTAreal Flood WarningPHIMontgomery, Philadelphia3 hr
Aug 19, 10:40 AM EDTAreal Flood WarningPHIDelaware3 hr

Nearby

Tornado Warnings in Pennsylvania, 2021Every tornado warning in 2021Tornadoes 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.