Alert archive / New Jersey / Flash Flood Watches in 2018

Flash Flood Watch 1, NWS Philadelphia/Mount Holly

April 15, 201810 counties in New Jersey; 10 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood watch at Apr 15, 2018, 3:41 PM EDT for 10 counties in New Jersey; 10 counties in Pennsylvania. It took effect at Apr 16, 2018, 2:00 AM EDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued
Apr 15, 2018, 3:41 PM EDT (19:41 UTC)
In effect from
Apr 16, 2018, 2:00 AM EDT
Expired
Apr 16, 2018, 12:02 PM EDT
In force
10 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 19:47 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, 7.7 hours before the alert went out and 196 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 12:00Z on 2018-04-15Temperature 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 12:00Z on 2018-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 201 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
682 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
201 m²/s²
0-3 km storm-relative helicity
447 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

587 
WGUS61 KPHI 151941
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
341 PM EDT Sun Apr 15 2018

NJZ001-007>010-012-015-017>019-PAZ054-055-061-062-070-071-103>106-
160900-
/O.NEW.KPHI.FF.A.0001.180416T0600Z-180416T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-Mercer-
Gloucester-Camden-Northwestern Burlington-Carbon-Monroe-Lehigh-
Northampton-Delaware-Philadelphia-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, New Brunswick, Trenton, Glassboro, 
Camden, Cherry Hill, Moorestown, Mount Holly, Jim Thorpe, 
Stroudsburg, Allentown, Bethlehem, Easton, Media, Philadelphia, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
341 PM EDT Sun Apr 15 2018

...FLASH FLOOD WATCH IN EFFECT FROM 2 AM EDT MONDAY THROUGH
MONDAY AFTERNOON...

The National Weather Service in Mount Holly has issued a

* Flash Flood Watch for portions of New Jersey and Pennsylvania, 
  including the following areas, in New Jersey, Camden, 
  Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern 
  Burlington, Somerset, Sussex, and Warren. In Pennsylvania, 
  Carbon, Delaware, Eastern Montgomery, Lehigh, Lower Bucks, 
  Monroe, Northampton, Philadelphia, Upper Bucks, and Western 
  Montgomery. 

* From 2 AM EDT Monday through Monday afternoon

* A line of strong thunderstorms is expected to move through the
  area late tonight and Monday morning. Widespread rainfall totals
  of one to three inches are forecast, with locally higher amounts
  possible with the strongest storms. The storms will likely move
  out of the area by Monday afternoon.

* The areas of greatest risk are poor-drainage and urban locations
  where rapid runoff may cause localized flash flooding. Quickly
  responding small streams may also experience flooding in areas
  receiving the heaviest rainfall. The storms are expected to move
  through the area just before or during the morning commute.
  Motorists should be prepared for torrential downpours and
  potential flooding as the storms move through.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that there is the potential for flash
flooding which can be life-threatening. Heavy rain is expected to
occur over a short period of time. Rapidly rising flood waters
may quickly inundate roadways and areas of poor drainage. Streams
and creeks could leave their banks, flooding nearby properties.

Please monitor the forecast, especially if you live in a location
that is prone to flooding. Be prepared to take action if a flash 
flood warning is issued for your area.

&&

$$

CMS
2 follow-up statements
939 
WGUS61 KPHI 160537
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
137 AM EDT Mon Apr 16 2018



PAZ060-101-102-161700-
/O.EXA.KPHI.FF.A.0001.180416T0600Z-180416T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks-Western Chester-Eastern Chester-
Including the cities of Reading, Honey Brook, Oxford, 
West Chester, and Kennett Square
137 AM EDT Mon Apr 16 2018

...FLASH FLOOD WATCH IN EFFECT THROUGH THIS AFTERNOON...

The National Weather Service in Mount Holly has expanded the

* Flash Flood Watch to include portions of east central 
  Pennsylvania and southeast Pennsylvania, including the 
  following areas, in east central Pennsylvania, Berks. In 
  southeast Pennsylvania, Eastern Chester and Western Chester. 

* Through this afternoon

* A line of strong thunderstorms is expected to move through the
  area early this morning. Widespread rainfall totals of one to 
  three inches are forecast, with locally higher amounts possible 
  with the strongest storms. The storms will likely move out of 
  the area by this afternoon. 

* The areas of greatest risk are poor-drainage and urban 
  locations where rapid runoff may cause localized flash 
  flooding. Quickly responding small streams may also experience 
  flooding in areas receiving the heaviest rainfall. The storms 
  are expected to move through the area just before or during 
  the morning commute. Motorists should be prepared for 
  torrential downpours and potential flooding as the storms move 
  through. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that there is the potential for flash
flooding which can be life-threatening. Heavy rain is expected to
occur over a short period of time. Rapidly rising flood waters
may quickly inundate roadways and areas of poor drainage. Streams
and creeks could leave their banks, flooding nearby properties.

Please monitor the forecast, especially if you live in a location
that is prone to flooding. Be prepared to take action if a flash
flood warning is issued for your area.

&&

$$

NJZ001-007>010-012-015-017>019-PAZ054-055-061-062-070-071-103>106-
161700-
/O.CON.KPHI.FF.A.0001.180416T0600Z-180416T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-Mercer-
Gloucester-Camden-Northwestern Burlington-Carbon-Monroe-Lehigh-
Northampton-Delaware-Philadelphia-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, New Brunswick, Trenton, Glassboro, 
Camden, Cherry Hill, Moorestown, Mount Holly, Jim Thorpe, 
Stroudsburg, Allentown, Bethlehem, Easton, Media, Philadelphia, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
137 AM EDT Mon Apr 16 2018

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS AFTERNOON...

The Flash Flood Watch continues for

* Portions of New Jersey and Pennsylvania, including the 
  following areas, in New Jersey, Camden, Gloucester, Hunterdon, 
  Mercer, Middlesex, Morris, Northwestern Burlington, Somerset, 
  Sussex, and Warren. In Pennsylvania, Carbon, Delaware, Eastern 
  Montgomery, Lehigh, Lower Bucks, Monroe, Northampton, 
  Philadelphia, Upper Bucks, and Western Montgomery. 

* Through this afternoon

* A line of strong thunderstorms is expected to move through the
  area early this morning. Widespread rainfall totals of one to 
  three inches are forecast, with locally higher amounts possible 
  with the strongest storms. The storms will likely move out of 
  the area by Monday afternoon. 

* The areas of greatest risk are poor-drainage and urban 
  locations where rapid runoff may cause localized flash 
  flooding. Quickly responding small streams may also experience 
  flooding in areas receiving the heaviest rainfall. The storms 
  are expected to move through the area just before or during 
  the morning commute. Motorists should be prepared for 
  torrential downpours and potential flooding as the storms move 
  through. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that there is the potential for flash
flooding which can be life-threatening. Heavy rain is expected to
occur over a short period of time. Rapidly rising flood waters
may quickly inundate roadways and areas of poor drainage. Streams
and creeks could leave their banks, flooding nearby properties.

Please monitor the forecast, especially if you live in a location
that is prone to flooding. Be prepared to take action if a flash
flood warning is issued for your area.

&&

$$
729 
WGUS61 KPHI 161602
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
1202 PM EDT Mon Apr 16 2018

NJZ001-007>010-012-015-017>019-PAZ054-055-060>062-070-071-101>106-
161715-
/O.CAN.KPHI.FF.A.0001.000000T0000Z-180416T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-Mercer-
Gloucester-Camden-Northwestern Burlington-Carbon-Monroe-Berks-
Lehigh-Northampton-Delaware-Philadelphia-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks-
Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, New Brunswick, Trenton, Glassboro, 
Camden, Cherry Hill, Moorestown, Mount Holly, Jim Thorpe, 
Stroudsburg, Reading, Allentown, Bethlehem, Easton, Media, 
Philadelphia, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
1202 PM EDT Mon Apr 16 2018

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of New Jersey and Pennsylvania
has been cancelled. 

The steady moderate to heavy rainfall has exited the area, 
therefore the Flash Flood Watch has been cancelled. However, there
will be some scattered showers or isolated thunderstorms through 
this afternoon.

There will remain some residual flooding into this afternoon and
evening. Several Flood Warnings and Flood Advisories remain in
effect, so please see these statements for the latest updates.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 15, 6:08 AM EDTCoastal Flood WatchPHIMiddlesex, Monmouth, Ocean9 hr
Apr 15, 6:08 AM EDTCoastal Flood AdvisoryPHIMiddlesex, Monmouth, Ocean4 hr
Apr 15, 6:08 AM EDTCoastal Flood AdvisoryPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 2 more39 hr
Apr 15, 2:44 PM EDTCoastal Flood WarningPHIAtlantic, Burlington, Cape May, Cumberland, Middlesex, Monmouth and 2 more23 hr

Nearby

Flash Flood Watches in New Jersey, 2018Flash Flood Watches in Pennsylvania, 2018Every flash flood watch in 2018

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.