Alert archive / New Jersey / Flood Watches in 2009

Flood Watch 3, NWS Philadelphia/Mount Holly

May 6, 2009Delaware County, Philadelphia County, Pennsylvania; 5 counties in New Jersey; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flood watch at May 6, 2009, 9:01 PM EDT for Delaware County, Philadelphia County, Pennsylvania; 5 counties in New Jersey; New Castle County, Delaware. It was in force for 19 hr.

The area

The counties it named.

The facts

Issued
May 6, 2009, 9:01 PM EDT (01:01 UTC)
Expired
May 7, 2009, 3:51 PM EDT
In force
19 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties New Castle County, DE, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Somerset County, NJ, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 49 km from the middle of the area, began a volume at 01:02 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, 1.0 hours before the alert went out and 185 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 2009-05-07Temperature 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 00:00Z on 2009-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 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
760 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
94 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 
WGUS61 KPHI 070101
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
901 PM EDT WED MAY 6 2009

DEZ001-NJZ009-010-012-013-015-PAZ067>071-071000-
/O.NEW.KPHI.FA.A.0003.090507T0101Z-090507T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-HUNTERDON-SOMERSET-MIDDLESEX-WESTERN MONMOUTH-MERCER-
CHESTER-MONTGOMERY-BUCKS-DELAWARE-PHILADELPHIA-
INCLUDING THE CITIES OF...WILMINGTON...FLEMINGTON...SOMERVILLE...
NEW BRUNSWICK...FREEHOLD...TRENTON...WEST CHESTER...NORRISTOWN...
DOYLESTOWN...MEDIA...PHILADELPHIA
901 PM EDT WED MAY 6 2009

...FLOOD WATCH IN EFFECT THROUGH THURSDAY MORNING...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A

* FLOOD WATCH FOR PORTIONS OF NORTHERN DELAWARE...NEW JERSEY AND 
 SOUTHEAST PENNSYLVANIA...INCLUDING THE FOLLOWING AREAS...IN 
 NORTHERN DELAWARE...NEW CASTLE. IN NEW JERSEY...HUNTERDON...
 MERCER...MIDDLESEX...SOMERSET AND WESTERN MONMOUTH. IN 
 SOUTHEAST PENNSYLVANIA...BUCKS...CHESTER...DELAWARE...
 MONTGOMERY AND PHILADELPHIA.

* THROUGH THURSDAY MORNING

* TWO BANDS OF THUNDERSTORMS WITH HEAVY RAIN ARE EXPECTED TO
  AFFECT THE REGION. ONE WILL MOVE THROUGH LATER THIS EVENING WITH
  A SECOND BAND EXPECTED AROUND MORNING. THE FLOOD WATCH AREA HAS
  HAD THE HEAVIEST OF THE RAINS SO FAR THIS MONTH AND ARE THE MOST
  VULNERABLE TO FLOODING. IN SOME LOCATIONS OF LOWER BUCKS AND
  MONTGOMERY COUNTIES AS WELL AS NORTHERN MIDDLESEX COUNTY ONLY
  ABOUT AN INCH OF RAIN WITHIN SIX HOURS WOULD START FLOODING.
  VULNERABLE STREAMS INCLUDE AND ARE NOT LIMITED TO THE CHRISTINA
  RIVER IN NEW CASTLE COUNTY...CHESTER CREEK IN DELAWARE COUNTY...
  THE PERKIOMEN CREEK IN MONTGOMERY COUNTY...THE NESHAMINY CREEK
  IN BUCKS COUNTY AND THE ASSUNPINK CREEK IN MERCER COUNTY.  
   
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON
CURRENT FORECASTS.

YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE
FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.

&&

$$

GIGI/OHARA
3 follow-up statements
000 
WGUS61 KPHI 070634
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
234 AM EDT THU MAY 7 2009

DEZ001-NJZ009-010-012-013-015-PAZ067>071-071600-
/O.EXT.KPHI.FA.A.0003.000000T0000Z-090507T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-HUNTERDON-SOMERSET-MIDDLESEX-WESTERN MONMOUTH-MERCER-
CHESTER-MONTGOMERY-BUCKS-DELAWARE-PHILADELPHIA-
INCLUDING THE CITIES OF...WILMINGTON...FLEMINGTON...SOMERVILLE...
NEW BRUNSWICK...FREEHOLD...TRENTON...WEST CHESTER...NORRISTOWN...
DOYLESTOWN...MEDIA...PHILADELPHIA
234 AM EDT THU MAY 7 2009

...FLOOD WATCH NOW IN EFFECT UNTIL NOON EDT TODAY...

THE FLOOD WATCH IS NOW IN EFFECT FOR

* PORTIONS OF NORTHERN DELAWARE...NEW JERSEY AND SOUTHEAST 
 PENNSYLVANIA...INCLUDING THE FOLLOWING AREAS...IN NORTHERN 
 DELAWARE...NEW CASTLE. IN NEW JERSEY...HUNTERDON...MERCER...
 MIDDLESEX...SOMERSET AND WESTERN MONMOUTH. IN SOUTHEAST 
 PENNSYLVANIA...BUCKS...CHESTER...DELAWARE...MONTGOMERY AND 
 PHILADELPHIA.

* UNTIL NOON EDT TODAY

* HEAVY RAIN AND SCATTERED THUNDERSTORMS WILL AFFECT THE REGION
  INTO THIS MORNING. RAINFALL RATES OF AN INCH IN LESS THAN AN
  HOUR ARE POSSIBLE. VULNERABLE STREAMS INCLUDE AND ARE NOT
  LIMITED TO THE CHRISTINA RIVER IN NEW CASTLE COUNTY...CHESTER
  CREEK IN DELAWARE COUNTY... THE PERKIOMEN CREEK IN MONTGOMERY
  COUNTY...THE NESHAMINY CREEK IN BUCKS COUNTY AND THE ASSUNPINK
  CREEK IN MERCER COUNTY.

* EARLY MORNING COMMUTERS WILL PROBABLY SEE DELAYS DUE TO FLOODING
  IN POOR DRAINAGE AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON
CURRENT FORECASTS.

YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE
FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.

&&

$$

RNS
000 
WGUS61 KPHI 071530
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1130 AM EDT THU MAY 7 2009

DEZ001-NJZ009-010-012-013-015-PAZ067>071-072100-
/O.EXT.KPHI.FA.A.0003.000000T0000Z-090507T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-HUNTERDON-SOMERSET-MIDDLESEX-WESTERN MONMOUTH-MERCER-
CHESTER-MONTGOMERY-BUCKS-DELAWARE-PHILADELPHIA-
INCLUDING THE CITIES OF...WILMINGTON...FLEMINGTON...SOMERVILLE...
NEW BRUNSWICK...FREEHOLD...TRENTON...WEST CHESTER...NORRISTOWN...
DOYLESTOWN...MEDIA...PHILADELPHIA
1130 AM EDT THU MAY 7 2009

...FLOOD WATCH NOW IN EFFECT UNTIL 5 PM EDT THIS AFTERNOON...

THE FLOOD WATCH IS NOW IN EFFECT FOR

* PORTIONS OF NORTHERN DELAWARE...NEW JERSEY AND SOUTHEAST 
 PENNSYLVANIA...INCLUDING THE FOLLOWING AREAS...IN NORTHERN 
 DELAWARE...NEW CASTLE. IN NEW JERSEY...HUNTERDON...MERCER...
 MIDDLESEX...SOMERSET AND WESTERN MONMOUTH. IN SOUTHEAST 
 PENNSYLVANIA...BUCKS...CHESTER...DELAWARE...MONTGOMERY AND 
 PHILADELPHIA.

* UNTIL 5 PM EDT THIS AFTERNOON

* ANOTHER ROUND OF SHOWERS IS EXPECTED TO MOVE THROUGH THE
  DELAWARE VALLEY AND INTERSTATE 95 CORRIDOR THIS AFTERNOON. THIS
  IS THE NINTH DAY IN A ROW THAT THE REGION HAS EXPERIENCED
  RAINFALL. WHILE MAIN STEM RIVERS STILL HAVE ROOM TO HANDLE
  RUNOFF, MANY SMALLER CREEKS AND STREAMS ARE RUNNING HIGH. THERE
  ARE STILL ABOUT A HALF-DOZEN TRIBUTARIES ABOVE CAUTION STAGE
  FROM LAST NIGHTS RAINFALL.

* MOST AREAS WILL ONLY SEE A FEW HUNDREDTHS TO A TENTH OR TWO OF
  NEW RAINFALL, BUT RADAR AND LIGHTNING DETECTION SYSTEMS INDICATE
  THAT THE APPROACHING ACTIVITY DOES IN FACT HAVE A CONVECTIVE
  CONTRIBUTION. THEREFORE ISOLATED HEAVIER RAINFALL CANNOT BE
  RULED OUT. BECAUSE CREEKS AND STREAMS ARE ALREADY RUNNING HIGH,
  FLOOD GUIDANCE INDICATES THAT LESS THAN ONE-HALF OF AN INCH OF
  RAINFALL IN AN HOUR COULD SEND WATER OVER SOME BANKS. AS A
  RESULT, THE FLOOD WATCH HAS BEEN EXTENDED THROUGH 500 PM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON
CURRENT FORECASTS.

MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE FLOOD WARNINGS.
THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE PREPARED TO TAKE
ACTION SHOULD FLOODING DEVELOP.

&&

$$

KRUZDLO/GORSE
000 
WGUS61 KPHI 071951
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
351 PM EDT THU MAY 7 2009

DEZ001-NJZ009-010-012-013-015-PAZ067>071-072100-
/O.CAN.KPHI.FA.A.0003.000000T0000Z-090507T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NEW CASTLE-HUNTERDON-SOMERSET-MIDDLESEX-WESTERN MONMOUTH-MERCER-
CHESTER-MONTGOMERY-BUCKS-DELAWARE-PHILADELPHIA-
INCLUDING THE CITIES OF...WILMINGTON...FLEMINGTON...SOMERVILLE...
NEW BRUNSWICK...FREEHOLD...TRENTON...WEST CHESTER...NORRISTOWN...
DOYLESTOWN...MEDIA...PHILADELPHIA
351 PM EDT THU MAY 7 2009

...FLOOD WATCH IS CANCELLED...

THE FLOOD WATCH FOR PORTIONS OF NORTHERN DELAWARE, NEW JERSEY AND
SOUTHEAST PENNSYLVANIA HAS BEEN CANCELLED. 

THE THREAT FOR WIDESPREAD FLOODING HAS ENDED AS THE MORE ORGANIZED
SHOWERS AND THUNDERSTORMS MOVE TO THE EAST. AS A RESULT, THE FLOOD
WATCH HAS BEEN CANCELLED.

$$

GORSE

The office that day

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

IssuedProductOfficeCountiesLasted
May 7, 1:08 AM EDTFlash Flood WarningPHIChester, Montgomery6 hr
May 7, 1:43 AM EDTFlash Flood WarningPHIBucks5 hr
May 7, 1:51 AM EDTFlash Flood WarningPHIDelaware, Philadelphia5 hr
May 7, 10:15 AM EDTAreal Flood WarningPHIMontgomery3 hr
May 7, 1:42 PM EDTAreal Flood AdvisoryPHIBucks, Montgomery4 hr
May 7, 2:34 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia3 hr
May 7, 3:09 AM EDTAreal Flood AdvisoryPHIHunterdon, Morris2 hr
May 7, 1:22 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Salem4 hr
May 7, 1:43 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Middlesex, Somerset62 min
May 7, 2:01 PM EDTSpecial Marine WarningPHI89 min
May 7, 2:05 PM EDTSevere Thunderstorm WarningPHIAtlantic, Camden, Cumberland, Gloucester, Salem40 min
May 7, 2:53 PM EDTSpecial Marine WarningPHI97 min
May 7, 4:05 PM EDTSpecial Marine WarningPHI67 min
May 7, 2:00 AM EDTRiver Flood WarningPHINew Castle3 hr
May 7, 1:33 PM EDTSevere Thunderstorm WarningPHIKent, New Castle66 min

Nearby

Flood Watches in New Jersey, 2009Flood Watches in Pennsylvania, 2009Flood Watches in Delaware, 2009Every flood watch 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.