Alert archive / Pennsylvania / Areal Flood Warnings in 2012

Areal Flood Warning 43, NWS Philadelphia/Mount Holly

December 21, 2012Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Dec 21, 2012, 9:24 AM EST for Delaware 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
Dec 21, 2012, 9:24 AM EST (14:24 UTC)
Expired
Dec 21, 2012, 1:15 PM EST
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Delaware County, PA

The radar

The Philadelphia radar (KDIX), 84 km from the middle of the area, began a volume at 14:27 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 2.4 hours before the alert went out and 203 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, Washington/Dulle, VA at 12:00Z on 2012-12-21Temperature 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, Washington/Dulle, VA at 12:00Z on 2012-12-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -242 square meters per square second.1939587897117Sfc1 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
1099 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
-242 m²/s²
0-3 km storm-relative helicity
-92 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.

048 
WGUS41 KPHI 211424
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
924 AM EST FRI DEC 21 2012

PAC045-211815-
/O.NEW.KPHI.FA.W.0043.121221T1424Z-121221T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-
924 AM EST FRI DEC 21 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 115 PM EST

* AT 921 AM EST...CRUM CREEK AT NEWTOWN SQUARE REMAINED ABOVE FLOOD 
STAGE. THE RIVER GAGE INDICATED THAT THE WATER LEVEL HAS CRESTED AND 
IS BEGINNING TO RECEDE. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

DRIVING INTO FLOOD WATERS COULD PUT YOUR LIFE AT RISK AND COST YOU
THOUSANDS OF DOLLARS IN VEHICLE REPAIRS. FLOOD WATERS MAY BE DEEPER
THAN YOU THINK. TURN AROUND AND FIND AN ALTERNATE ROUTE.

&&

LAT...LON 3994 7553 3998 7545 4000 7545 4003 7541
      4004 7541 4007 7536 3996 7525 3994 7523
      3988 7526 3987 7521 3985 7526 3985 7533
      3980 7541 3983 7549 3984 7560 3987 7560

$$

KRUZDLO
1 follow-up statement
388 
WGUS81 KPHI 211808
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
108 PM EST FRI DEC 21 2012

PAC045-211817-
/O.EXP.KPHI.FA.W.0043.000000T0000Z-121221T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-
108 PM EST FRI DEC 21 2012

...THE FLOOD WARNING WILL EXPIRE AT 115 PM EST FOR URBAN AREAS AND
SMALL STREAMS IN DELAWARE COUNTY...

SMALL CREEKS AND STREAMS CONTINUE TO RECEDE. THE FLOOD WARNING WILL 
BE ALLOWED TO EXPIRE AT 115 PM.

LAT...LON 3994 7553 3998 7545 4000 7545 4003 7541
      4004 7541 4007 7536 3996 7525 3994 7523
      3988 7526 3987 7521 3985 7526 3985 7533
      3980 7541 3983 7549 3984 7560 3987 7560

$$

KRUZDLO

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 20, 9:00 PM ESTWinter Weather AdvisoryPHICarbon, Monroe2 hr
Dec 20, 9:11 PM ESTWind AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia12 hr
Dec 21, 12:27 AM ESTCoastal Flood WarningPHIDelaware, Philadelphia11 hr
Dec 21, 4:44 AM ESTAreal Flood WarningPHIChester, Montgomery14 hr
Dec 21, 5:17 AM ESTAreal Flood WarningPHIDelaware4 hr
Dec 21, 5:39 AM ESTAreal Flood WarningPHIBucks10 hr
Dec 21, 7:15 AM ESTRiver Flood WarningPHIDelaware4 hr
Dec 21, 7:36 AM ESTAreal Flood WarningPHIMonroe, Northampton15 hr
Dec 21, 7:49 AM ESTAreal Flood WarningPHIPhiladelphia11 hr
Dec 21, 9:36 AM ESTRiver Flood WarningPHIBucks10 hr
Dec 21, 12:08 PM ESTRiver Flood WarningPHIChester, Delaware5 hr
Dec 21, 3:16 PM ESTWind AdvisoryPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more27 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.