Alert archive / Pennsylvania / Flash Flood Warnings in 2009

Flash Flood Warning 58, NWS Philadelphia/Mount Holly

August 28, 2009Bucks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 28, 2009, 9:16 AM EDT for Bucks 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 28, 2009, 9:16 AM EDT (13:16 UTC)
Expired
Aug 28, 2009, 1:15 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

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

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 13:15 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 12:00Z, 1.3 hours before the alert went out and 207 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 2009-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2009-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1046 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
24 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 281316
FFWPHI
PAC017-077-095-281715-
/O.NEW.KPHI.FF.W.0058.090828T1316Z-090828T1715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
916 AM EDT FRI AUG 28 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  SOUTH CENTRAL NORTHAMPTON COUNTY IN EASTERN PENNSYLVANIA...
  NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 115 PM EDT

* AT 906 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN ACROSS BERKS AND LANCASTER COUNTIES. THIS RAIN WAS      
  MOVING NORTHEAST. AN ADDITIONAL ONE TO TWO INCHES OF RAIN IS       
  POSSIBLE OVER THE NEXT FEW HOURS ACROSS THE WARNED AREA. THIS IS   
  IN ADDITION TO THE TWO TO ALMOST FOUR INCHES THAT FELL IN SPOTS    
  EARLIER THIS MORNING. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS INCLUDES THE FOLLOWING STREAMS AND DRAINAGES...
DELAWARE RIVER...LEHIGH RIVER...EAST BRANCH SAUCON CREEK...CEDAR
CREEK...JORDAN CREEK...SAUCON CREEK...IRON RUN...COOKS CREEK...LITTLE
LEHIGH CREEK...SCHAEFER RUN...GALLOWS RUN...RAPP CREEK...TUMBLE
BROOK...HAYCOCK CREEK...UNAMI CREEK...SWABIA CREEK...DIMPLE CREEK...
TOHICKON CREEK...HOSENSACK CREEK...PERKIOMEN CREEK...BEAVER RUN...
SCHMOUTZ CREEK...MACOBY CREEK AND STONY RUN.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS 
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 4058 7519 4056 7519 4055 7517 4052 7514
      4040 7547 4054 7568 4062 7523

$$

KRUZDLO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 28, 9:42 AM EDTAreal Flood AdvisoryPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton2 hr
Aug 28, 2:52 PM EDTFlash Flood WatchPHIBerks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more14 hr
Aug 28, 3:13 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia4 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.