Alert archive / Pennsylvania / Flash Flood Warnings in 2019

Flash Flood Warning 63, NWS Philadelphia/Mount Holly

July 21, 2019Berks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 21, 2019, 10:31 PM EDT for Berks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 3 hr. 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
Jul 21, 2019, 10:31 PM EDT (02:31 UTC)
Expired
Jul 22, 2019, 1:38 AM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

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

The radar

The Philadelphia radar (KDIX), 133 km from the middle of the area, began a volume at 02:35 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
Jul 21, 10:50 PM EDTFLASH FLOODEmmaus, PAWIDESPREAD ROADWAY FLOODING.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 2.5 hours before the alert went out and 224 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 00:00Z on 2019-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 157 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 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 00:00Z on 2019-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -73 square meters per square second.1939Sfc1 km3 km6 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
157 J/kg
Mixed-layer CIN
-308 J/kg
Mixed-layer LCL
1994 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-73 m²/s²
0-3 km storm-relative helicity
-77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

759 
WGUS51 KPHI 220231
FFWPHI
PAC011-077-095-220630-
/O.NEW.KPHI.FF.W.0063.190722T0231Z-190722T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1031 PM EDT Sun Jul 21 2019

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern Berks County in eastern Pennsylvania...
  Southern Lehigh County in eastern Pennsylvania...
  South central Northampton County in eastern Pennsylvania...

* Until 230 AM EDT.

* At 1030 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to two inches of rain has 
  already fallen in a short amount of time. Flash flooding is 
  expected to begin shortly in the areas of heaviest rain.

* Some locations that could experience flooding include...
  Allentown, Bethlehem, Emmaus, Hellertown, Kutztown, Hamburg,
  Topton, Shoemakersville, Lyons, Lenhartsville, Zionsville, Ancient
  Oaks, Lehigh University, Claussville, Fountain Hill, Macungie,
  Freemansburg, Coopersburg, Alburtis and Centerport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 4051 7629 4058 7605 4057 7602 4063 7599
      4063 7520 4051 7538 4043 7547 4045 7553
      4044 7554

$$

Robertson
2 follow-up statements
704 
WGUS71 KPHI 220418
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1218 AM EDT Mon Jul 22 2019

PAC011-220427-
/O.CAN.KPHI.FF.W.0063.000000T0000Z-190722T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
1218 AM EDT Mon Jul 22 2019

...THE FLASH FLOOD WARNING FOR NORTHERN BERKS COUNTY IS CANCELLED...

Additional flooding is no longer expected to pose a threat in Berks 
County. Please continue to heed any remaining road closures.

LAT...LON 4063 7520 4051 7538 4043 7547 4045 7554
      4063 7582

$$

PAC077-095-220630-
/O.CON.KPHI.FF.W.0063.000000T0000Z-190722T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
1218 AM EDT Mon Jul 22 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM EDT FOR
SOUTHERN LEHIGH AND SOUTH CENTRAL NORTHAMPTON COUNTIES...

At 1210 AM EDT, Doppler radar indicated thunderstorms producing 
heavy rain in the Lehigh Valley. Up to two or three inches of rain 
have already fallen in spots.

Some locations that could experience flooding include...
Allentown, Emmaus, Hellertown, Ancient Oaks, Zionsville, Macungie,
Coopersburg and Alburtis.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other poor drainage areas and low lying spots.

&&

LAT...LON 4063 7520 4051 7538 4043 7547 4045 7554
      4063 7582

$$

Iovino
679 
WGUS71 KPHI 220538
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
138 AM EDT Mon Jul 22 2019

PAC077-095-220548-
/O.CAN.KPHI.FF.W.0063.000000T0000Z-190722T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
138 AM EDT Mon Jul 22 2019

...THE FLASH FLOOD WARNING FOR SOUTHERN LEHIGH AND SOUTH CENTRAL
NORTHAMPTON COUNTIES IS CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 4063 7520 4051 7538 4043 7547 4045 7554
      4063 7582

$$

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 8:25 PM EDTSpecial Weather StatementPHICarbon, Lehigh, Northampton50 min
Jul 21, 8:44 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton46 min
Jul 21, 9:24 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Northampton51 min
Jul 21, 9:30 PM EDTSevere Thunderstorm WarningPHIChester45 min
Jul 21, 9:58 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Lehigh, Montgomery, Northampton2 hr
Jul 21, 10:14 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton46 min
Jul 21, 10:30 PM EDTFlash Flood WarningPHIBerks, Lehigh, Northampton3 hr
Jul 21, 10:35 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh40 min
Jul 21, 10:42 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery48 min
Jul 21, 10:54 PM EDTSevere Thunderstorm WarningPHIDelaware25 min
Jul 21, 10:58 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery59 min
Jul 21, 11:05 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery40 min
Jul 21, 11:31 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia44 min
Jul 21, 11:38 PM EDTFlash Flood WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton2 hr
Jul 21, 11:40 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Carbon, Lehigh, Montgomery, Northampton50 min
Jul 22, 12:05 AM EDTSevere Thunderstorm WarningPHICarbon, Monroe40 min
Jul 22, 12:45 AM EDTSpecial Weather StatementPHIMonroe30 min
Jul 22, 1:11 AM EDTSpecial Weather StatementPHIMonroe34 min
Jul 22, 5:32 AM EDTAreal Flood WarningPHILehigh49 min
Jul 22, 1:28 PM EDTSpecial Weather StatementPHIMonroe32 min
Jul 22, 1:50 PM EDTSpecial Weather StatementPHINorthampton25 min
Jul 22, 3:18 PM EDTSpecial Weather StatementPHIChester57 min
Jul 22, 3:27 PM EDTSevere Thunderstorm WarningPHIMonroe48 min
Jul 22, 3:33 PM EDTAreal Flood AdvisoryPHICarbon, Monroe, Northampton7 hr
Jul 22, 3:39 PM EDTSpecial Weather StatementPHIBerks51 min
Jul 22, 3:47 PM EDTSevere Thunderstorm WarningPHIChester, Delaware58 min
Jul 22, 4:11 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton4 hr
Jul 22, 4:16 PM EDTSevere Thunderstorm WarningPHIChester, Delaware59 min
Jul 22, 4:40 PM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia114 min
Jul 22, 4:55 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton50 min
Jul 22, 5:04 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia41 min
Jul 22, 5:05 PM EDTFlash Flood WarningPHIBerks, Lehigh, Northampton4 hr
Jul 22, 5:14 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia61 min
Jul 22, 5:17 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton73 min
Jul 22, 5:34 PM EDTFlash Flood WarningPHIBucks, Lehigh, Montgomery, Northampton4 hr
Jul 22, 5:40 PM EDTSevere Thunderstorm WarningPHIBucks, Philadelphia80 min
Jul 22, 5:43 PM EDTAreal Flood AdvisoryPHIBucks3 hr
Jul 22, 5:50 PM EDTSevere Thunderstorm WarningPHIBucks40 min

Nearby

Flash Flood Warnings in Pennsylvania, 2019Every flash flood 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.