Alert archive / New York / Flash Flood Warnings in 2024

Flash Flood Warning 21, NWS New York, NY

August 18, 20244 counties in New York; Bergen County, Passaic County, New Jersey

NWS New York, NY issued this flash flood warning at Aug 18, 2024, 5:46 PM EDT for 4 counties in New York; Bergen County, Passaic County, New Jersey. It was in force for 3 hr. 2 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 18, 2024, 5:46 PM EDT (21:46 UTC)
Expired
Aug 18, 2024, 8:45 PM EDT
In force
3 hr
Issued by
NWS New York, NY
Area
Storm-based polygon
Flood severity
None

Counties Bergen County, NJ, Passaic County, NJ, Orange County, NY, Putnam County, NY, Rockland County, NY, Westchester County, NY

The radar

The Brookhaven radar (KOKX), 131 km from the middle of the area, began a volume at 21:46 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

TimeReportWhereRemark
Aug 18, 6:45 PM EDTFLASH FLOOD1 S Bloomingdale, NJMultiple streets closed due to flooding along Glenwild Avenue.
Aug 18, 6:45 PM EDTFLASH FLOOD1 S Bloomingdale, NJMultiple streets closed due to flooding along Glenwild Avenue.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 9.8 hours before the alert went out and 131 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 2024-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 109 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 2024-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 square meters per square second.193958Sfc1 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
109 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
582 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
205 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

270 
WGUS51 KOKX 182146
FFWOKX
NJC003-031-NYC071-079-087-119-190045-
/O.NEW.KOKX.FF.W.0021.240818T2146Z-240819T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New York NY
546 PM EDT Sun Aug 18 2024

The National Weather Service in Upton has issued a

* Flash Flood Warning for...
  Northwestern Bergen County in northeastern New Jersey...
  Passaic County in northeastern New Jersey...
  Orange County in southeastern New York...
  Western Putnam County in southeastern New York...
  Rockland County in southeastern New York...
  Northern Westchester County in southeastern New York...

* Until 845 PM EDT.

* At 546 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. The expected rainfall rate is 1 to 2 inches in 1 hour. 
  Additional rainfall amounts of 1 to 3 inches are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  New City, Newburgh, Middletown, West Milford, Peekskill, Monsey, 
  Ramsey, Ringwood, Haverstraw, Pompton Lakes, Suffern, Port Jervis, 
  Monroe, Walden, West Point, Warwick, Goshen, Sloatsburg, Cold 
  Spring and Howells.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of urban 
areas, highways, streets and underpasses as well as other drainage 
areas and low lying spots.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4151 7448 4157 7442 4163 7426 4159 7419
      4158 7413 4162 7413 4158 7405 4159 7395
      4145 7400 4149 7388 4127 7377 4096 7428
      4100 7430 4102 7443 4105 7445 4104 7450
      4109 7450 4120 7437 4137 7470 4150 7455

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

JM
2 follow-up statements
539 
WGUS71 KOKX 182352
FFSOKX

Flash Flood Statement
National Weather Service New York NY
752 PM EDT Sun Aug 18 2024

NJC003-031-NYC071-079-087-119-190045-
/O.CON.KOKX.FF.W.0021.000000T0000Z-240819T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bergen NJ-Passaic NJ-Orange NY-Putnam NY-Rockland NY-Westchester
NY-
752 PM EDT Sun Aug 18 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM EDT THIS 
EVENING FOR NORTHWESTERN BERGEN, PASSAIC, SOUTHEASTERN ORANGE, 
WESTERN PUTNAM, ROCKLAND AND NORTHERN WESTCHESTER COUNTIES...

At 752 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.5 and 1 inch of rain has 
fallen. The expected rainfall rate is 1 inch in 1 hour. Additional 
rainfall amounts up to 1 inch are possible in the warned area. Flash 
flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  New City, West Milford, Peekskill, Monsey, Ramsey, Ringwood, 
  Haverstraw, Pompton Lakes, Suffern, Monroe, West Point, 
  Sloatsburg, Cold Spring, Bloomingdale, Greenwood Lake, Pomona, 
  Harriman, Yorktown Heights, Upper Greenwood Lake and Spring Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of urban 
areas, highways, streets and underpasses as well as other drainage 
areas and low lying spots.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4129 7431 4134 7415 4144 7414 4142 7406
      4145 7400 4144 7398 4146 7396 4149 7388
      4127 7377 4096 7428 4100 7430 4103 7442
      4102 7443 4104 7443 4105 7445 4104 7450
      4107 7449 4109 7450 4120 7437

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1 INCH IN 1 HOUR

$$

JM
624 
WGUS71 KOKX 190051
FFSOKX

Flash Flood Statement
National Weather Service New York NY
851 PM EDT Sun Aug 18 2024

NJC003-031-NYC071-079-087-119-190101-
/O.EXP.KOKX.FF.W.0021.000000T0000Z-240819T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bergen NJ-Passaic NJ-Orange NY-Putnam NY-Rockland NY-Westchester
NY-
851 PM EDT Sun Aug 18 2024

...FLASH FLOOD WARNING HAS EXPIRED FOR NORTHWESTERN BERGEN, PASSAIC, 
SOUTHEASTERN ORANGE, WESTERN PUTNAM, ROCKLAND AND NORTHERN 
WESTCHESTER COUNTIES...

Flash flooding is no longer posing an imminent threat, but minor 
flooding poor drainage and low lying flooding is likely. Please 
continue to heed remaining road closures. This warning will likely 
be replaced by a Flood Advisory.

A Flood Watch remains in effect until 200 AM EDT for portions of 
southern Connecticut and southeast New York.

A Flood Watch remains in effect until 200 AM EDT for portions of 
northeast New Jersey and southeast New York.

&&

LAT...LON 4129 7431 4134 7415 4144 7414 4142 7406
      4145 7400 4144 7398 4146 7396 4149 7388
      4127 7377 4096 7428 4100 7430 4103 7442
      4102 7443 4104 7443 4105 7445 4104 7450
      4107 7449 4109 7450 4120 7437

$$

NV

The office that day

Everything else NWS New York, NY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 17, 9:08 PM EDTCoastal Flood StatementOKXKings, Queens, Richmond25 hr
Aug 17, 9:08 PM EDTCoastal Flood AdvisoryOKXNassau, Westchester28 hr
Aug 18, 4:07 AM EDTAreal Flood AdvisoryOKXBronx, Kings, New York, Queens, Richmond, Westchester113 min
Aug 18, 6:30 AM EDTAreal Flood AdvisoryOKXNassau, Queens, Suffolk3 hr
Aug 18, 7:07 AM EDTAreal Flood AdvisoryOKXWestchester2 hr
Aug 18, 8:29 AM EDTAreal Flood AdvisoryOKXBronx, Queens, Westchester61 min
Aug 18, 9:26 AM EDTFlash Flood WarningOKXWestchester6 hr
Aug 18, 11:26 AM EDTAreal Flood AdvisoryOKXPutnam, Westchester2 hr
Aug 18, 3:31 PM EDTAreal Flood AdvisoryOKXWestchester100 min
Aug 18, 4:45 PM EDTAreal Flood AdvisoryOKXWestchester3 hr
Aug 18, 5:54 PM EDTSevere Thunderstorm WarningOKXOrange, Rockland51 min
Aug 18, 6:11 PM EDTSpecial Weather StatementOKXRichmond49 min
Aug 18, 6:38 PM EDTFlash Flood WarningOKXRockland3 hr
Aug 18, 7:17 PM EDTFlash Flood WarningOKXBronx, New York, Richmond, Rockland, Westchester3 hr
Aug 18, 7:24 PM EDTSpecial Marine WarningOKX51 min
Aug 18, 7:32 PM EDTSpecial Weather StatementOKXKings, Queens, Richmond43 min
Aug 18, 7:41 PM EDTAreal Flood AdvisoryOKXBronx, Kings, Nassau, New York, Queens, Westchester3 hr
Aug 18, 7:48 PM EDTSpecial Marine WarningOKX42 min
Aug 18, 6:28 PM EDTSevere Thunderstorm WarningOKXBergen, Essex, Passaic, Union47 min

Nearby

Flash Flood Warnings in New York, 2024Flash Flood Warnings in New Jersey, 2024Every flash flood warning in 2024

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.