Alert archive / Pennsylvania / Flash Flood Watches in 2021

Flash Flood Watch 1, NWS Philadelphia/Mount Holly

June 3, 20214 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood watch at Jun 3, 2021, 9:37 AM EDT for 4 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware. It took effect at Jun 3, 2021, 3:00 PM EDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Jun 3, 2021, 9:37 AM EDT (13:37 UTC)
In effect from
Jun 3, 2021, 3:00 PM EDT
Expired
Jun 3, 2021, 10:00 PM EDT
In force
7 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 72 km from the middle of the area, began a volume at 13:40 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, 1.6 hours before the alert went out and 213 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 2021-06-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 73 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, Washington/Dulle, VA at 12:00Z on 2021-06-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 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
73 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
511 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
118 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

084 
WGUS61 KPHI 031337
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Mount Holly NJ
937 AM EDT Thu Jun 3 2021

DEZ001-NJZ016>019-PAZ070-071-101>106-040145-
/O.NEW.KPHI.FF.A.0001.210603T1900Z-210604T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Salem-Gloucester-Camden-Northwestern Burlington-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Glassboro, Lansdale, Chalfont, Mount Holly, 
Morrisville, Cherry Hill, Moorestown, West Chester, Wilmington, 
Philadelphia, Doylestown, Collegeville, Pottstown, Camden, Media, 
Oxford, Pennsville, Honey Brook, Kennett Square, Perkasie, and 
Norristown
937 AM EDT Thu Jun 3 2021

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM EDT THIS AFTERNOON THROUGH 
THIS EVENING...

The National Weather Service in Mount Holly has issued a

* Flash Flood Watch for portions of northern Delaware...southern New 
  Jersey...and southeast Pennsylvania...including the following 
  areas...in northern Delaware...New Castle. In southern New 
  Jersey...Camden, Gloucester, Northwestern Burlington, and Salem. 
  In southeast Pennsylvania...Delaware, Eastern Chester, Eastern 
  Montgomery, Lower Bucks, Philadelphia, Upper Bucks, Western 
  Chester, and Western Montgomery.

* From 3 PM EDT this afternoon through this evening.

* Showers and thunderstorms are expected to develop by mid afternoon 
  over western Maryland into central Pennsylvania and move eastward 
  into the region by late this afternoon into this evening. These 
  storms will be capable of producing heavy rainfall over a short 
  period of time which may result in flash flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Fitzsimmons
2 follow-up statements
618 
WGUS61 KPHI 031922
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
322 PM EDT Thu Jun 3 2021

DEZ001-NJZ016>019-PAZ070-071-101>106-040200-
/O.CON.KPHI.FF.A.0001.000000T0000Z-210604T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Salem-Gloucester-Camden-Northwestern Burlington-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Glassboro, Lansdale, Chalfont, Mount Holly, 
Morrisville, Cherry Hill, Moorestown, West Chester, Wilmington, 
Philadelphia, Doylestown, Collegeville, Pottstown, Camden, Media, 
Oxford, Pennsville, Honey Brook, Kennett Square, Perkasie, and 
Norristown
322 PM EDT Thu Jun 3 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 10 PM EDT THIS 
EVENING...

The Flash Flood Watch continues for

* Portions of northern Delaware...southern New Jersey...and 
  southeast Pennsylvania...including the following areas...in 
  northern Delaware...New Castle. In southern New Jersey...Camden, 
  Gloucester, Northwestern Burlington, and Salem. In southeast 
  Pennsylvania...Delaware, Eastern Chester, Eastern Montgomery, 
  Lower Bucks, Philadelphia, Upper Bucks, Western Chester, and 
  Western Montgomery.

* Until 10 PM EDT this evening.

* Developing showers and thunderstorms will continue to increase in 
  coverage and move eastward into the region by late this afternoon 
  into this evening. These storms will be capable of producing heavy 
  rainfall over a short period of time which may result in flash 
  flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Fitzsimmons
648 
WGUS61 KPHI 040149
FFAPHI

Flood Watch
National Weather Service Mount Holly NJ
949 PM EDT Thu Jun 3 2021

DEZ001-NJZ016>019-PAZ070-071-101>106-040300-
/O.EXP.KPHI.FF.A.0001.000000T0000Z-210604T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle-Salem-Gloucester-Camden-Northwestern Burlington-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Glassboro, Lansdale, Chalfont, Mount Holly, 
Morrisville, Cherry Hill, Moorestown, West Chester, Wilmington, 
Philadelphia, Doylestown, Collegeville, Pottstown, Camden, Media, 
Oxford, Pennsville, Honey Brook, Kennett Square, Perkasie, and 
Norristown
949 PM EDT Thu Jun 3 2021

...FLASH FLOOD WATCH WILL EXPIRE AT 10 PM EDT THIS EVENING...

The Flash Flood Watch for portions of northern Delaware...southern 
New Jersey...and southeast Pennsylvania...including the following 
areas...in northern Delaware...New Castle. In southern New Jersey...
Camden, Gloucester, Northwestern Burlington, and Salem. In southeast 
Pennsylvania...Delaware, Eastern Chester, Eastern Montgomery, Lower 
Bucks, Philadelphia, Upper Bucks, Western Chester, and Western 
Montgomery will expire at 10 PM EDT this evening.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a threat. Please continue to heed remaining road closures.

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 3, 5:55 PM EDTSpecial Marine WarningPHI65 min
Jun 3, 6:33 PM EDTSevere Thunderstorm WarningPHIAtlantic, Cape May, Cumberland, Salem42 min
Jun 3, 7:07 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 2 more38 min
Jun 3, 7:09 PM EDTFlash Flood WarningPHICamden, Gloucester, Salem2 hr
Jun 3, 7:13 PM EDTAreal Flood AdvisoryPHIBurlington, Hunterdon, Mercer, Middlesex, Somerset3 hr
Jun 3, 7:52 PM EDTSevere Thunderstorm WarningPHIBurlington, Ocean38 min
Jun 3, 3:02 PM EDTSpecial Weather StatementPHIBerks43 min
Jun 3, 3:54 PM EDTSpecial Weather StatementPHIBerks36 min
Jun 3, 5:14 PM EDTSevere Thunderstorm WarningPHIBerks, Chester27 min
Jun 3, 5:20 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Delaware, Montgomery, Philadelphia3 hr
Jun 3, 5:59 PM EDTFlash Flood WarningPHIBerks, Chester108 min
Jun 3, 6:19 PM EDTFlash Flood WarningPHIBerks, Chester, Montgomery115 min
Jun 3, 5:33 PM EDTSpecial Weather StatementPHISussex42 min

Nearby

Flash Flood Watches in Pennsylvania, 2021Flash Flood Watches in New Jersey, 2021Flash Flood Watches in Delaware, 2021Every flash flood watch in 2021

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.