Alert archive / New Jersey / Flash Flood Warnings in 2009

Flash Flood Warning 32, NWS Philadelphia/Mount Holly

August 12, 2009Mercer County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 12, 2009, 12:47 PM EDT for Mercer County, New Jersey. It was in force for 3 hr. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 12, 2009, 12:47 PM EDT (16:47 UTC)
Expired: Aug 12, 2009, 3:39 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Mercer County, NJ

The radar

The Philadelphia radar (KDIX), 31 km from the middle of the area, began a volume at 16:48 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.

What was reported inside it

Time	Report	Where	Remark
Aug 12, 12:57 PM EDT	FLASH FLOOD	2 Ese Hamilton Square, NJ	MAJOR FLOODING IN ROBBINSVILLE TWP ALONG ROUTE 130. ALSO REPORTS OF SMALL HAIL.
Aug 12, 1:25 PM EDT	FLASH FLOOD	2 Ese Hamilton Square, NJ	6 INCHES OF FLOWING WATER AT INTERSECTION OF ROUTE 130 AND MEADOWBROOK ROAD IN ROBBINSVILLE TWP.
Aug 12, 1:45 PM EDT	FLASH FLOOD	2 Ese Hamilton Square, NJ	TWO FEET OF WATER AGAINST 8 TO 10 HOUSES ALONG CHARLENE COURT IN ROBBINSVILLE TWP.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 4.8 hours before the alert went out and 153 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: 402 J/kg
Mixed-layer CIN: -103 J/kg
Mixed-layer LCL: 1048 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 111 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 121647
FFWPHI
NJC021-122045-
/O.NEW.KPHI.FF.W.0032.090812T1647Z-090812T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1247 PM EDT WED AUG 12 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN MERCER COUNTY IN CENTRAL NEW JERSEY...

* UNTIL 445 PM EDT

* AT 1236 PM EDT...HEAVY RAIN CONTINUED TO FALL ACROSS PORTIONS OF 
HAMILTON TOWNSHIP AS WELL AS ROBBINSVILLE TOWNSHIP, FORMERLY KNOWN 
AS WASHINGTON TOWNSHIP. EVEN THOUGH THE THUNDERSTORM RESPONSIBLE FOR 
THE HEAVY RAIN WAS ISOLATED AND RELATIVELY SMALL, IT WAS NEARLY 
STATIONARY. NATIONAL WEATHER SERVICE DOPPLER RADAR RAINFALL 
ESTIMATES INDICATED THAT TWO TO THREE INCHES OF RAIN HAVE FALLEN 
ACROSS PORTIONS OF THE WARNED AREA, INCLUDING THE ROUTE 130 
CORRIDOR JUST NORTH OF INTERSTATE 195. MORE RAIN IS EXPECTED. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. JUST ONE FOOT OF FLOWING WATER IS POWERFUL ENOUGH TO SWEEP 
YOUR VEHICLE OFF THE ROAD. TURN AROUND...DONT DROWN. 

&&

LAT...LON 4021 7455 4017 7458 4018 7460 4017 7461
      4013 7460 4013 7461 4017 7468 4024 7472
      4027 7450 4026 7448 4024 7448

$$

KRUZDLO

1 follow-up statement

000 
WGUS71 KPHI 121939
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
339 PM EDT WED AUG 12 2009

NJC021-121945-
/O.CAN.KPHI.FF.W.0032.000000T0000Z-090812T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MERCER NJ-
339 PM EDT WED AUG 12 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHEASTERN MERCER
COUNTY...

WATER CONTINUES TO DRAIN AND RECEDE. THE FLASH FLOOD WARNING HAS 
BEEN CANCELLED.

KEEP IN MIND THAT MORE THUNDERSTORMS ARE POSSIBLE INTO THIS EVENING 
WHICH COULD CAUSE RENEWED FLOODING.

LAT...LON 4021 7455 4017 7458 4018 7460 4017 7461
      4013 7460 4013 7461 4017 7468 4024 7472
      4027 7450 4026 7448 4024 7448

$$

KRUZDLO

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 12:04 PM EDT	Areal Flood Advisory	PHI	Mercer	60 min
Aug 12, 1:26 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	22 min
Aug 12, 2:55 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	50 min
Aug 12, 3:01 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cumberland	59 min
Aug 12, 3:17 PM EDT	Flash Flood Warning	PHI	Atlantic, Cumberland	4 hr
Aug 12, 3:29 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	60 min
Aug 12, 3:32 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Ocean	118 min
Aug 12, 4:01 PM EDT	Flash Flood Warning	PHI	Atlantic, Cape May	3 hr
Aug 12, 4:16 PM EDT	Flash Flood Warning	PHI	Cumberland, Salem	6 hr
Aug 12, 4:55 PM EDT	Flash Flood Warning	PHI	Salem	3 hr
Aug 12, 5:13 PM EDT	Areal Flood Advisory	PHI	Cape May, Cumberland	2 hr
Aug 12, 6:03 PM EDT	Areal Flood Advisory	PHI	Sussex	4 hr

Nearby

Flash Flood Warnings in New Jersey, 2009 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.