Alert archive / Pennsylvania / Flash Flood Watches in 2015

Flash Flood Watch 1, NWS Philadelphia/Mount Holly

May 31, 20156 counties in Pennsylvania; 6 counties in New Jersey

NWS Philadelphia/Mount Holly issued this flash flood watch at May 31, 2015, 1:11 PM EDT for 6 counties in Pennsylvania; 6 counties in New Jersey. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued
May 31, 2015, 1:11 PM EDT (17:11 UTC)
Expired
Jun 1, 2015, 2:00 AM EDT
In force
13 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties Hunterdon 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, Lehigh County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 103 km from the middle of the area, began a volume at 17:12 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, 5.2 hours before the alert went out and 189 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 2015-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 106 joules per kilogram.LCLLFCEL10008507005003002001001 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 2015-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.1939Sfc1 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
106 J/kg
Mixed-layer CIN
-105 J/kg
Mixed-layer LCL
746 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
41 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.

499 
WGUS61 KPHI 311711
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
111 PM EDT SUN MAY 31 2015


NJZ001-007-008-PAZ054-055-062-010300-
/O.NEW.KPHI.FF.A.0001.150531T1711Z-150601T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-CARBON-MONROE-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
JIM THORPE...STROUDSBURG...BETHLEHEM...EASTON
111 PM EDT SUN MAY 31 2015

...FLASH FLOOD WATCH IN EFFECT UNTIL 11 PM EDT THIS EVENING...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF NORTHERN NEW JERSEY AND 
  PENNSYLVANIA...INCLUDING THE FOLLOWING AREAS...IN NORTHERN NEW 
  JERSEY...MORRIS...SUSSEX AND WARREN. IN PENNSYLVANIA... 
  CARBON...MONROE AND NORTHAMPTON. 

* UNTIL 11 PM EDT THIS EVENING

* LOCATIONS...A PORTION OF NORTHEAST PENNSYLVANIA INCLUDING THE
  POCONOS AS WELL AS FAR NORTHWEST NEW JERSEY. 

* BANDS OF THUNDERSTORMS ARE EXPECTED TO PRODUCE SWATHS OF
  EXCESSIVE SHORT DURATION RAINFALL, POSSIBLY AS MUCH AS 2 INCHES
  IN AN HOUR. IF THESE TORRENTIAL RAINS OCCUR, POCKETS OF
  DANGEROUS STREET AND HIGHWAY FLOODING WOULD RESULT SOMETIME THIS
  AFTERNOON OR EVENING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

GORSE/DRAG
4 follow-up statements
063 
WGUS61 KPHI 311932
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
332 PM EDT SUN MAY 31 2015


NJZ001-007-008-PAZ054-055-062-010300-
/O.CON.KPHI.FF.A.0001.000000T0000Z-150601T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-CARBON-MONROE-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
JIM THORPE...STROUDSBURG...BETHLEHEM...EASTON
332 PM EDT SUN MAY 31 2015

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF NORTHWESTERN NEW JERSEY AND NORTHEAST PENNSYLVANIA...
  INCLUDING THE FOLLOWING AREAS...IN NORTHWESTERN NEW JERSEY...
  MORRIS...SUSSEX AND WARREN. IN NORTHEAST PENNSYLVANIA...
  CARBON...MONROE AND NORTHAMPTON.

* UNTIL 11 PM EDT THIS EVENING

* CONDITIONS ARE FAVORABLE FOR THE DEVELOPMENT OF WIDESPREAD HEAVY
  RAINS FROM BANDS OF THUNDERSTORMS IN THE WATCH AREA ALONG AND
  NORTH OF ROUTE 80 LATE THIS AFTERNOON AND EVENING. THESE
  THUNDERSTORMS MAY PRODUCE NARROW SWATHS OF EXCESSIVE SHORT
  DURATION RAINFALL... POSSIBLY AS MUCH AS 2 INCHES IN AN HOUR
  WITH ISOLATED STORM TOTALS NEAR 4 INCHES. IF THESE TORRENTIAL
  RAINS OCCUR... POCKETS OF DANGEROUS STREET AND HIGHWAY FLOODING
  WOULD RESULT SOMETIME VERY LATE THIS AFTERNOON OR MORE LIKELY
  EARLY THIS EVENING.

* THERE WAS A REPORT EARLIER THIS AFTERNOON OF 1.5 INCHES OF RAIN
  IN 45 MINUTES FROM FORKS TOWNSHIP IN NORTHAMPTON COUNTY
  PENNSYLVANIA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$
855 
WGUS61 KPHI 312207
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
607 PM EDT SUN MAY 31 2015

NJZ009-010-012-PAZ060-061-105-010600-
/O.EXB.KPHI.FF.A.0001.000000T0000Z-150601T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HUNTERDON-SOMERSET-MIDDLESEX-BERKS-LEHIGH-UPPER BUCKS-
INCLUDING THE CITIES OF...FLEMINGTON...SOMERVILLE...
NEW BRUNSWICK...READING...ALLENTOWN...CHALFONT...PERKASIE
607 PM EDT SUN MAY 31 2015

...FLASH FLOOD WATCH IN EFFECT UNTIL 2 AM EDT MONDAY...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS EXPANDED THE

* FLASH FLOOD WATCH TO INCLUDE PORTIONS OF NEW JERSEY AND
  PENNSYLVANIA...INCLUDING THE FOLLOWING AREAS...IN NEW JERSEY...
  HUNTERDON...MIDDLESEX AND SOMERSET. IN PENNSYLVANIA...BERKS...
  LEHIGH AND UPPER BUCKS.

* UNTIL 2 AM EDT MONDAY

* CONDITIONS ARE FAVORABLE FOR THE DEVELOPMENT OF AREAS OF HEAVY
  RAINS FROM BANDS OF THUNDERSTORMS IN THE WATCH AREA. THESE
  THUNDERSTORMS MAY PRODUCE NARROW SWATHS OF EXCESSIVE SHORT
  DURATION RAINFALL... POSSIBLY AS MUCH AS 2 INCHES IN AN HOUR
  WITH ISOLATED STORM TOTALS NEAR 4 INCHES. IF THESE TORRENTIAL
  RAINS OCCUR... POCKETS OF DANGEROUS STREET AND HIGHWAY FLOODING
  WOULD RESULT SOMETIME EARLY TONIGHT.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

NJZ001-007-008-PAZ054-055-062-010600-
/O.EXT.KPHI.FF.A.0001.000000T0000Z-150601T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-CARBON-MONROE-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
JIM THORPE...STROUDSBURG...BETHLEHEM...EASTON
607 PM EDT SUN MAY 31 2015

...FLASH FLOOD WATCH NOW IN EFFECT UNTIL 2 AM EDT MONDAY...

THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR

* PORTIONS OF NORTHERN NEW JERSEY AND PENNSYLVANIA...INCLUDING 
  THE FOLLOWING AREAS...IN NORTHERN NEW JERSEY...MORRIS...SUSSEX 
  AND WARREN. IN PENNSYLVANIA...CARBON...MONROE AND NORTHAMPTON. 

* UNTIL 2 AM EDT MONDAY

* CONDITIONS CONTINUE FAVORABLE FOR THE DEVELOPMENT OF WIDESPREAD
  HEAVY RAINS FROM BANDS OF THUNDERSTORMS IN THE WATCH AREA THIS
  EVENING. THESE THUNDERSTORMS MAY PRODUCE NARROW SWATHS OF
  EXCESSIVE SHORT DURATION RAINFALL... POSSIBLY AS MUCH AS 2
  INCHES IN AN HOUR WITH ISOLATED STORM TOTALS NEAR 4 INCHES. IF
  THESE TORRENTIAL RAINS OCCUR... POCKETS OF DANGEROUS STREET AND
  HIGHWAY FLOODING WOULD RESULT SOMETIME EARLY TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

DRAG
420 
WGUS61 KPHI 010105
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
905 PM EDT SUN MAY 31 2015

NJZ001-007>010-012-PAZ054-055-060>062-105-010600-
/O.CON.KPHI.FF.A.0001.000000T0000Z-150601T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-CARBON-MONROE-
BERKS-LEHIGH-NORTHAMPTON-UPPER BUCKS-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
FLEMINGTON...SOMERVILLE...NEW BRUNSWICK...JIM THORPE...
STROUDSBURG...READING...ALLENTOWN...BETHLEHEM...EASTON...
CHALFONT...PERKASIE
905 PM EDT SUN MAY 31 2015

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 2 AM EDT MONDAY...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF NEW JERSEY AND PENNSYLVANIA...INCLUDING THE 
  FOLLOWING AREAS...IN NEW JERSEY...HUNTERDON...MIDDLESEX... 
  MORRIS...SOMERSET...SUSSEX AND WARREN. IN PENNSYLVANIA... 
  BERKS...CARBON...LEHIGH...MONROE...NORTHAMPTON AND UPPER 
  BUCKS. 

* UNTIL 2 AM EDT MONDAY

* WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS COVER MUCH OF THE
  WATCH AREA THIS EVENING. THERE COULD STILL BE POCKETS OF FLASH
  FLOODING LATER THIS EVENING. THUNDERSTORMS SHOULD DECREASE IN
  COVERAGE AFTER 2 AM.

* SO FAR, ABOUT 5 INCHES OF RAIN HAS FALLEN IN NORTHEAST MIDDLESEX
  COUNTY WHERE ANOTHER BATCH OF HEAVY SHOWERS SHOULD OCCUR IN
  MIDDLESEX COUNTY TOWARD MIDNIGHT. 

* ELSEWHERE, AS OF 9 PM WE KNOW OF 1.5 TO 2 INCH AMOUNTS IN PARTS
  OF MONROE AND CARBON COUNTIES IN THE POCONOS AND UNDOUBTEDLY
  HEAVIER AMOUNTS FELL THERE...POSSIBLY ISOLATED REPORTS NEAR 5
  INCHES, ESPECIALLY IN SOUTHERN CARBON COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO A RAPID RISE OF WATER TO DANGEROUS LEVELS. FLASH FLOODING IS A
VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$
779 
WGUS61 KPHI 010553
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
153 AM EDT MON JUN 1 2015


NJZ001-007>010-012-PAZ054-055-060>062-105-010700-
/O.EXP.KPHI.FF.A.0001.000000T0000Z-150601T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-CARBON-MONROE-
BERKS-LEHIGH-NORTHAMPTON-UPPER BUCKS-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
FLEMINGTON...SOMERVILLE...NEW BRUNSWICK...JIM THORPE...
STROUDSBURG...READING...ALLENTOWN...BETHLEHEM...EASTON...
CHALFONT...PERKASIE
153 AM EDT MON JUN 1 2015

...FLASH FLOOD WATCH WILL EXPIRE AT 2 AM EDT EARLY THIS MORNING...

THE FLASH FLOOD WATCH FOR PORTIONS OF NEW JERSEY AND PENNSYLVANIA
WILL EXPIRE AT 2 AM EDT EARLY THIS MORNING. 

WHILE RAIN WILL CONTINUE THROUGH THE OVERNIGHT HOURS, THE HEAVIEST
RAIN HAS ENDED. RAINFALL WILL BE STEADY, BUT LIGHTER.  THE NEED
FOR ADDITIONAL WATCHES IS BEING EVALUATED AT THIS TIME.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 30, 8:19 PM EDTSpecial Weather StatementPHICarbon56 min
May 30, 8:46 PM EDTSpecial Weather StatementPHILebanon29 min
May 30, 9:03 PM EDTAreal Flood AdvisoryPHIBerks3 hr
May 30, 9:11 PM EDTSpecial Weather StatementPHILebanon64 min
May 30, 9:20 PM EDTSpecial Weather StatementPHICarbon55 min
May 30, 9:36 PM EDTAreal Flood AdvisoryPHICarbon3 hr
May 31, 1:00 PM EDTSevere Thunderstorm WarningPHINorthampton45 min
May 31, 4:33 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton42 min
May 31, 5:12 PM EDTSevere Thunderstorm WarningPHIMonroe63 min
May 31, 5:23 PM EDTSevere Thunderstorm WarningPHIBerks37 min
May 31, 5:42 PM EDTFlash Flood WarningPHICarbon, Monroe6 hr
May 31, 7:08 PM EDTSpecial Weather StatementPHILehigh82 min
May 31, 7:27 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh5 hr
May 31, 7:46 PM EDTFlash Flood WarningPHIBerks, Lehigh4 hr
May 31, 7:48 PM EDTSevere Thunderstorm WarningPHIBerks35 min
May 31, 7:57 PM EDTAreal Flood AdvisoryPHILehigh, Northampton6 hr
May 31, 1:24 PM EDTSpecial Weather StatementPHIMonmouth36 min
May 31, 2:00 PM EDTSpecial Weather StatementPHIMonmouth45 min
May 31, 5:57 PM EDTSmall Craft AdvisoryPHI6 hr
May 31, 6:11 PM EDTAreal Flood AdvisoryPHIMiddlesex, Somerset3 hr
May 31, 6:37 PM EDTFlash Flood WarningPHIMiddlesex5 hr
May 31, 6:50 PM EDTSevere Thunderstorm WarningPHIMiddlesex, Monmouth40 min

Nearby

Flash Flood Watches in Pennsylvania, 2015Flash Flood Watches in New Jersey, 2015Every flash flood watch in 2015

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.