Alert archive / Pennsylvania / Flash Flood Warnings in 2015

Flash Flood Warning 54, NWS Philadelphia/Mount Holly

September 12, 20154 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 12, 2015, 4:55 PM EDT for 4 counties in Pennsylvania. It was in force for 2 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
Sep 12, 2015, 4:55 PM EDT (20:55 UTC)
Expired
Sep 12, 2015, 7:00 PM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Carbon County, PA, Lehigh County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 131 km from the middle of the area, began a volume at 20:58 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 12, 5:33 PM EDTHEAVY RAIN 3.22Shankweilers, PA3 INCHES OF RAIN FELL IN AN HOUR FROM 417-518 PM

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, 8.9 hours before the alert went out and 226 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 2015-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 73 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 2015-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.193958Sfc1 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
73 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

426 
WGUS51 KPHI 122055
FFWPHI
PAC025-077-089-095-122300-
/O.NEW.KPHI.FF.W.0054.150912T2055Z-150912T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
455 PM EDT SAT SEP 12 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WEST CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  SOUTHWESTERN MONROE COUNTY IN NORTHEASTERN PENNSYLVANIA...
  SOUTHEASTERN CARBON COUNTY IN NORTHEASTERN PENNSYLVANIA...

* UNTIL 700 PM EDT
    
* AT 453 PM EDT...DOPPLER RADAR AND AUTOMATED RAIN GAUGES INDICATED 
  A THUNDERSTORM PRODUCING HEAVY RAIN ACROSS THE WARNED AREA. TWO 
  INCHES OF RAINFALL IS OCCURRING IN AN HOUR. UP TO THREE INCHES OF 
  RAIN HAVE ALREADY FALLEN TODAY. FLASH FLOODING IS EXPECTED TO 
  BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ALLENTOWN...BETHLEHEM...EMMAUS...NORTHAMPTON...PALMERTON...
  SLATINGTON...WIND GAP...BATH...WALNUTPORT...STORMVILLE...NEW
  TRIPOLI...BEERSVILLE...DANIELSVILLE...ROSSLAND...CLAUSSVILLE...
  BERLINSVILLE...BELTZVILLE STATE PARK...BRODHEADSVILLE...
  SCHNECKSVILLE AND MCMICHAEL.

ADDITIONAL RAINFALL AMOUNTS AROUND AN INCH ARE POSSIBLE IN THE 
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4097 7523 4062 7543 4047 7557 4048 7558
      4060 7577 4062 7579 4080 7571 4094 7563
      4103 7549

$$

JRK
2 follow-up statements
013 
WGUS71 KPHI 122200
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
600 PM EDT SAT SEP 12 2015

PAC025-089-095-122206-
/O.CAN.KPHI.FF.W.0054.000000T0000Z-150912T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NORTHAMPTON PA-MONROE PA-CARBON PA-
600 PM EDT SAT SEP 12 2015

...THE FLASH FLOOD WARNING FOR WEST CENTRAL NORTHAMPTON...
SOUTHWESTERN MONROE AND SOUTHEASTERN CARBON COUNTIES IS CANCELLED...

THE HEAVY RAINFALL STAYED SOUTH OF THE AREA IN LEHIGH VALLEY. 
THEREFORE...FLOODING IS NOT EXPECTED TO POSE A THREAT.

LAT...LON 4059 7575 4068 7573 4071 7570 4076 7563
      4073 7559 4069 7555 4065 7552 4059 7552
      4052 7561

$$

PAC077-122300-
/O.CON.KPHI.FF.W.0054.000000T0000Z-150912T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LEHIGH PA-
600 PM EDT SAT SEP 12 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR
CENTRAL LEHIGH COUNTY...

AT 556 PM EDT...DOPPLER RADAR AND AUTOMATED RAIN GAUGES INDICATED
THAT HEAVY RAIN WAS FALLING OVER THE AREA. UP TO THREE INCHES OF 
RAIN FELL IN LESS THAN TWO HOURS. SHOWERS HAVE ALREADY TAPERED OFF 
BUT EXCESSIVE RUNOFF FROM THE EARLIER HEAVY RAIN MAY PRODUCE FLASH 
FLOODING SHORTLY.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
ALLENTOWN...SLATINGTON...EMERALD...SCHNECKSVILLE...NEFFS...
COFFEETOWN...CLAUSSVILLE AND ANCIENT OAKS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

PLEASE REPORT FLOODING TO YOUR LOCAL LAW ENFORCEMENT AGENCY WHEN YOU
CAN DO SO SAFELY.

&&

LAT...LON 4059 7575 4068 7573 4071 7570 4076 7563
      4073 7559 4069 7555 4065 7552 4059 7552
      4052 7561

$$

JRK
102 
WGUS71 KPHI 122246
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
646 PM EDT SAT SEP 12 2015

PAC077-122256-
/O.CAN.KPHI.FF.W.0054.000000T0000Z-150912T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LEHIGH PA-
646 PM EDT SAT SEP 12 2015

...THE FLASH FLOOD WARNING FOR CENTRAL LEHIGH COUNTY IS CANCELLED...

THE HEAVY RAIN HAS ENDED...AND FLOODING IS NO LONGER EXPECTED TO POSE
A THREAT.

LAT...LON 4059 7575 4068 7573 4071 7570 4076 7563
      4073 7559 4069 7555 4065 7552 4059 7552
      4052 7561

$$

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 12, 3:14 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh3 hr
Sep 12, 4:48 PM EDTSpecial Weather StatementPHILehigh, Monroe, Northampton42 min

Nearby

Flash Flood Warnings in Pennsylvania, 2015Every flash flood warning in 2015

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.