Alert archive / Pennsylvania / Areal Flood Warnings in 2012

Areal Flood Warning 27, NWS Philadelphia/Mount Holly

October 2, 2012Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Oct 2, 2012, 6:23 PM EDT for Montgomery County, Pennsylvania. It was in force for 65 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Oct 2, 2012, 6:23 PM EDT (22:23 UTC)
Expired
Oct 2, 2012, 7:28 PM EDT
In force
65 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 106 km from the middle of the area, began a volume at 22:26 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.4 hours before the alert went out and 111 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, Phillips Aaf/Abe, MD at 12:00Z on 2012-10-02Temperature 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, Phillips Aaf/Abe, MD at 12:00Z on 2012-10-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 307 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
654 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
307 m²/s²
0-3 km storm-relative helicity
375 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.

405 
WGUS41 KPHI 022223
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
623 PM EDT TUE OCT 2 2012

PAC091-030115-
/O.NEW.KPHI.FA.W.0027.121002T2223Z-121003T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-
623 PM EDT TUE OCT 2 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR...
  NORTHWESTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 915 PM EDT

* AT 620 PM EDT...THE PERKIOMEN CREEK AT EAST GREENVILLE WAS REACHING
  FLOOD STAGE DUE TO RAINFALL FROM EARLIER IN THE DAY. 

THIS FLOOD WARNING MEANS THAT MINOR FLOODING IS IMMINENT ALONG THE 
PERKIOMEN CREEK IN AND NEAR EAST GREENVILLE. FLASH FLOODING IS NOT 
EXPECTED. HOWEVER...ALL INTERESTED PARTIES SHOULD TAKE NECESSARY 
PRECAUTION IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN. BE ESPECIALLY 
CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE TH DANGERS OF FLOODING. 

&&

LAT...LON 4036 7560 4044 7553 4044 7552 4037 7540
      4027 7548 4033 7562

$$

MPD/TFG
1 follow-up statement
245 
WGUS81 KPHI 022328
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
728 PM EDT TUE OCT 2 2012

PAC091-022337-
/O.CAN.KPHI.FA.W.0027.000000T0000Z-121003T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-
728 PM EDT TUE OCT 2 2012

...THE FLOOD WARNING HAS BEEN CANCELLED FOR NORTHWESTERN MONTGOMERY
COUNTY...

RIVER GAUGES INDICATE THAT MINOR FLOODING HAS ENDED. 

LAT...LON 4036 7560 4044 7553 4044 7552 4037 7540
      4027 7548 4033 7562

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 2, 3:28 PM EDTAreal Flood AdvisoryPHIBucks, Lehigh, Northampton2 hr

Nearby

Areal Flood Warnings in Pennsylvania, 2012Every areal flood warning in 2012

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.