Alert archive / Pennsylvania / Flash Flood Warnings in 2013

Flash Flood Warning 69, NWS Philadelphia/Mount Holly

September 2, 2013Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 2, 2013, 5:39 PM EDT for Lehigh County, Pennsylvania. It was in force for 2 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: Sep 2, 2013, 5:39 PM EDT (21:39 UTC)
Expired: Sep 2, 2013, 8:00 PM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 125 km from the middle of the area, began a volume at 21:39 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, 9.7 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 791 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 538 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 75 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

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

234 
WGUS51 KPHI 022139
FFWPHI
PAC077-030000-
/O.NEW.KPHI.FF.W.0069.130902T2139Z-130903T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
539 PM EDT MON SEP 2 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  LEHIGH COUNTY...

* UNTIL 800 PM EDT...

* AT 535 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM SHOWERS AND THUNDERSTORMS MOVING ACROSS       
  LEHIGH COUNTY. RADAR ESTIMATES INDICATE RAINFALL AMOUNTS OF
  UP TO 2 INCHES HAS ALREADY FALLEN, AND AN ADDITIONAL 1 TO 2 INCHES
  IS POSSIBLE.

THIS AMOUNT OF RAINFALL IN A SHORT PERIOD OF TIME AND ON ALREADY 
SATURATED GROUND WILL RESULT IN QUICK FLOODING OF ROADWAYS AND LOW 
LYING AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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. NEVER ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR IN AN
AUTOMOBILE. TURN AROUND DON'T DROWN!

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

&&

LAT...LON 4076 7572 4079 7561 4074 7560 4072 7556
      4074 7553 4066 7548 4067 7543 4063 7539
      4062 7538 4058 7541 4053 7534 4042 7548
      4068 7589

$$

FORECASTER: GORSE

1 follow-up statement

707 
WGUS71 KPHI 022302
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
702 PM EDT MON SEP 2 2013

PAC077-022312-
/O.CAN.KPHI.FF.W.0069.000000T0000Z-130903T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LEHIGH PA-
702 PM EDT MON SEP 2 2013

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR LEHIGH COUNTY...

THE HEAVY SHOWERS AND THUNDERSTORMS HAVE CLEARED THE AREA, AND ANY 
LINGERING FLOODING WILL RECEDE. THEREFORE...THE FLASH FLOOD 
WARNING HAS BEEN CANCELLED.

LAT...LON 4076 7572 4079 7561 4074 7560 4072 7556
      4074 7553 4066 7548 4067 7543 4063 7539
      4062 7538 4058 7541 4053 7534 4042 7548
      4068 7589

$$

FORECASTER: GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 2, 4:56 AM EDT	Special Weather Statement	PHI	Carbon	49 min
Sep 2, 5:34 AM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	56 min
Sep 2, 7:09 AM EDT	Areal Flood Advisory	PHI	Northampton	4 hr
Sep 2, 9:37 AM EDT	Areal Flood Advisory	PHI	Philadelphia	113 min
Sep 2, 9:52 AM EDT	Flash Flood Warning	PHI	Philadelphia	4 hr
Sep 2, 10:29 AM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	76 min
Sep 2, 10:50 AM EDT	Areal Flood Advisory	PHI	Delaware	3 hr
Sep 2, 11:27 AM EDT	Areal Flood Advisory	PHI	Delaware, Montgomery, Philadelphia	3 hr
Sep 2, 12:37 PM EDT	Flash Flood Warning	PHI	Delaware	3 hr
Sep 2, 12:44 PM EDT	Flash Flood Warning	PHI	Bucks	4 hr
Sep 2, 3:06 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	114 min
Sep 2, 3:14 PM EDT	Special Weather Statement	PHI	Northampton	61 min
Sep 2, 4:02 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	43 min
Sep 2, 4:44 PM EDT	Special Weather Statement	PHI	Lehigh	46 min
Sep 2, 4:52 PM EDT	Special Weather Statement	PHI	Bucks	38 min
Sep 2, 5:05 PM EDT	Areal Flood Advisory	PHI	Lehigh	115 min
Sep 2, 5:46 PM EDT	Special Weather Statement	PHI	Lehigh	44 min
Sep 2, 6:57 PM EDT	Special Weather Statement	PHI	Montgomery	48 min
Sep 2, 7:59 PM EDT	Special Weather Statement	PHI	Chester	46 min

Nearby

Flash Flood Warnings in Pennsylvania, 2013 Every flash flood warning in 2013

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.