Alert archive / Pennsylvania / Flash Flood Warnings in 2009

Flash Flood Warning 41, NWS Philadelphia/Mount Holly

August 12, 2009Carbon County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 12, 2009, 10:33 PM EDT for Carbon County, Lehigh County, Northampton County, Pennsylvania. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 12, 2009, 10:33 PM EDT (02:33 UTC)
Expired
Aug 13, 2009, 2:18 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

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

The radar

The Philadelphia radar (KDIX), 142 km from the middle of the area, began a volume at 02:34 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

Brookhaven, NY (KOKX), launched 00:00Z, 2.6 hours before the alert went out and 240 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 2009-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 136 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 2009-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.19395878Sfc1 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
136 J/kg
Mixed-layer CIN
-72 J/kg
Mixed-layer LCL
544 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 130233
FFWPHI
PAC025-077-095-130630-
/O.NEW.KPHI.FF.W.0041.090813T0233Z-090813T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1033 PM EDT WED AUG 12 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  EXTREME WEST CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  SOUTH CENTRAL CARBON COUNTY IN NORTHEAST PENNSYLVANIA...

* UNTIL 230 AM EDT

* AT 1030 PM EDT...NATIONAL WEATHER SERVICE RADAR INDICATED FLASH
  FLOODING FROM CONTINUING HEAVY THUNDERSTORMS OVER THE WARNED AREA.
  RAIN RATES WERE BETWEEN 3 AND 4 INCHES AN HOUR.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO JORDAN
  VALLEY...EMERALD...WALNUTPORT...SLATINGTON AND PALMERTON

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

MOST FLOOD RELATED DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO 
CROSS WATER COVERED BRIDGES...DIPS...OR LOW WATER CROSSINGS. NEVER 
TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO 
ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 4080 7559 4068 7552 4066 7575 4072 7582
      4073 7581 4074 7578 4076 7580 4077 7580
      4084 7567

$$
1 follow-up statement
000 
WGUS71 KPHI 130618
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
218 AM EDT THU AUG 13 2009

PAC025-077-095-130630-
/O.CAN.KPHI.FF.W.0041.000000T0000Z-090813T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LEHIGH PA-NORTHAMPTON PA-CARBON PA-
218 AM EDT THU AUG 13 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTH CENTRAL
CARBON...EXTREME WEST CENTRAL NORTHAMPTON AND NORTHWESTERN LEHIGH
COUNTIES...

THE MOST INTENSE RAINS HAVE MOVED AWAY FROM THE AREA. AREA CREEKS 
AND STREMS MAY CONTINUE TO RUN HIGH FOR THE NEXT FEW HOURS. 

LAT...LON 4080 7559 4068 7552 4066 7575 4072 7582
      4073 7581 4074 7578 4076 7580 4077 7580
      4084 7567

$$

PO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 8:54 PM EDTFlash Flood WarningPHICarbon4 hr
Aug 12, 10:42 PM EDTFlash Flood WarningPHIBerks4 hr
Aug 12, 11:23 PM EDTFlash Flood WarningPHIBerks, Lehigh, Northampton7 hr
Aug 13, 2:58 AM EDTAreal Flood AdvisoryPHIChester3 hr
Aug 13, 3:36 AM EDTFlood WatchPHIBerks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more36 min
Aug 13, 4:12 AM EDTFlash Flood WatchPHIBerks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more15 hr
Aug 13, 6:01 AM EDTRiver Flood WarningPHIChester5 hr
Aug 13, 9:13 AM EDTRiver Flood WarningPHIChester, Delaware5 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2009Every flash flood warning in 2009

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.