Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 42, NWS New York, NY

September 1, 2021Suffolk County, New York

NWS New York, NY issued this flash flood warning at Sep 1, 2021, 11:13 PM EDT for Suffolk County, New York. It was in force for 6 hr. 1 report 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
Sep 1, 2021, 11:13 PM EDT (03:13 UTC)
Expired
Sep 2, 2021, 4:55 AM EDT
In force
6 hr
Issued by
NWS New York, NY
Area
Storm-based polygon
Flood severity
None

County Suffolk County, NY

The radar

The Brookhaven radar (KOKX), 39 km from the middle of the area, began a volume at 03:18 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
Sep 2, 1:00 AM EDTFLASH FLOOD1 Sw Port Jefferson, NYPORT JEFFERSON FIRE DEPARTMENT RESPONDED TO NUMEROUS WATER RESCUE EMERGENCIES. MULTIPLE OCCUPANTS WERE RESCUED BY THE FIRE DEPARTMENTS HIGH WATER UNIT AND SOME OCCUPANTS WERE FOUND ON THE ROOF OF THEIR VEHICLES, OR TRAPPED WITHIN FLOATING VEHICLES. THERE WAS A

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 00:00Z, 3.2 hours before the alert went out and 39 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 00:00Z on 2021-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 123 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 00:00Z on 2021-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 279 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
123 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
512 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
279 m²/s²
0-3 km storm-relative helicity
456 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

975 
WGUS51 KOKX 020313
FFWOKX
NYC103-020715-
/O.NEW.KOKX.FF.W.0042.210902T0313Z-210902T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New York NY
1113 PM EDT Wed Sep 1 2021

The National Weather Service in Upton has issued a

* Flash Flood Warning for...
  Suffolk County in southeastern New York...

* Until 315 AM EDT.

* At 1113 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have already fallen in spots in the warned area. The expected 
  rainfall rate is 1 to 2 inches in 1 hour. Additional rainfall 
  amounts of 2 to 4 inches are possible. 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...
  Islip, Riverhead, Centereach, Shirley, Medford, Southold, 
  Ronkonkoma, Manorville, Stony Brook, Patchogue, Middle Island, 
  Port Jefferson, Wading River, Center Moriches, Mattituck, 
  Westhampton, Sag Harbor, Bridgehampton, Fishers Island and Plum 
  Island.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 4067 7324 4073 7295 4069 7323 4098 7317
      4100 7265 4126 7205 4127 7207 4130 7190
      4110 7229 4106 7226 4104 7212 4110 7216
      4114 7213 4114 7212 4110 7206 4101 7209
      4109 7193 4106 7185 4061 7324

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

$$

Goodman
2 follow-up statements
993 
WGUS51 KOKX 020708
FFWOKX
NYC103-020915-
/O.EXT.KOKX.FF.W.0042.000000T0000Z-210902T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New York NY
308 AM EDT Thu Sep 2 2021

The National Weather Service in Upton has extended the

* Flash Flood Warning for...
  Suffolk County in southeastern New York...

* Until 515 AM EDT.

* At 308 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area across the South Fork of Long 
  Island. Between 1 and 4 inches of rain have fallen and there will 
  likely be some residual flooding from the earlier heavy rain for 
  the rest of Suffolk County. The expected rainfall rate is 1 to 2 
  inches in 1 hour for the ongoing thunderstorms. Additional 
  rainfall amounts of 1 to 2 inches are possible in the warned area 
  across the South Fork of Long Island. 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...
  Islip, Riverhead, Centereach, Shirley, Medford, Southold, 
  Ronkonkoma, Manorville, Stony Brook, Patchogue, Middle Island, 
  Port Jefferson, Wading River, Center Moriches, Mattituck, 
  Westhampton, Sag Harbor, Bridgehampton, Fishers Island and Plum 
  Island.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 4067 7324 4073 7295 4069 7323 4098 7317
      4100 7265 4126 7205 4127 7207 4130 7190
      4110 7229 4106 7226 4104 7212 4110 7216
      4114 7213 4114 7212 4110 7206 4101 7209
      4109 7193 4106 7185 4061 7324

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

$$

JM
594 
WGUS71 KOKX 020855
FFSOKX

Flash Flood Statement
National Weather Service New York NY
455 AM EDT Thu Sep 2 2021

NYC103-020905-
/O.CAN.KOKX.FF.W.0042.000000T0000Z-210902T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Suffolk NY-
455 AM EDT Thu Sep 2 2021

...FLASH FLOOD WARNING FOR SUFFOLK COUNTY HAS BEEN REPLACED WITH A 
FLOOD ADVISORY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

A Flash Flood Watch remains in effect until 1100 AM EDT Thursday for 
portions of southern Connecticut and southeast New York.

LAT...LON 4067 7324 4073 7295 4069 7323 4098 7317
      4100 7265 4126 7205 4127 7207 4130 7190
      4110 7229 4106 7226 4104 7212 4110 7216
      4114 7213 4114 7212 4110 7206 4101 7209
      4109 7193 4106 7185 4061 7324

$$

JM

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 8:32 PM EDTSevere Thunderstorm WarningOKXNew York, Richmond43 min
Sep 1, 9:03 PM EDTSevere Thunderstorm WarningOKXBronx, Kings, Nassau, New York, Queens, Westchester42 min
Sep 1, 9:06 PM EDTTornado WarningOKXBronx, New York, Westchester24 min
Sep 1, 9:15 PM EDTSpecial Marine WarningOKX60 min
Sep 1, 9:25 PM EDTSpecial Marine WarningOKX65 min
Sep 1, 9:25 PM EDTSevere Thunderstorm WarningOKXBronx, Kings, Nassau, New York, Queens, Rockland and 1 more65 min
Sep 1, 9:28 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatOKXBronx, Kings, New York, Queens, Westchester2 hr
Sep 1, 9:34 PM EDTSpecial Marine WarningOKX12 min
Sep 1, 9:56 PM EDTSpecial Marine WarningOKX34 min
Sep 1, 9:57 PM EDTSevere Thunderstorm WarningOKXKings, Nassau, Queens48 min
Sep 1, 10:08 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatOKXNassau, Westchester4 hr
Sep 1, 10:09 PM EDTSpecial Marine WarningOKX96 min
Sep 1, 10:12 PM EDTSpecial Marine WarningOKX20 min
Sep 1, 10:20 PM EDTSevere Thunderstorm WarningOKXWestchester55 min
Sep 1, 10:26 PM EDTSpecial Marine WarningOKX64 min
Sep 1, 10:30 PM EDTSevere Thunderstorm WarningOKXNassau, Suffolk45 min
Sep 1, 10:39 PM EDTTornado WarningOKXSuffolk36 min
Sep 1, 10:44 PM EDTSevere Thunderstorm WarningOKXNassau46 min
Sep 1, 10:47 PM EDTSpecial Marine WarningOKX118 min
Sep 1, 10:55 PM EDTSpecial Marine WarningOKX45 min
Sep 1, 11:11 PM EDTSevere Thunderstorm WarningOKXSuffolk64 min
Sep 1, 11:19 PM EDTSpecial Marine WarningOKX86 min
Sep 1, 11:54 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatOKXBronx, Kings, New York, Queens, Richmond, Westchester3 hr
Sep 2, 12:13 AM EDTSevere Thunderstorm Warning Considerable damage threatOKXSuffolk92 min
Sep 2, 12:25 AM EDTFlash Flood WarningOKXNassau, Queens, Suffolk4 hr
Sep 2, 12:28 AM EDTSpecial Marine WarningOKX92 min
Sep 2, 12:48 AM EDTRiver Flood WarningOKXOrange, Ulster12 hr
Sep 2, 1:06 AM EDTAreal Flood WarningOKXOrange, Putnam, Rockland, Westchester4 hr
Sep 2, 1:50 AM EDTSpecial Weather StatementOKXSuffolk40 min
Sep 2, 1:57 AM EDTSpecial Marine WarningOKX80 min
Sep 2, 2:30 AM EDTAreal Flood WarningOKXBronx, Nassau, Putnam, Queens, Rockland, Suffolk and 1 more8 hr
Sep 2, 2:53 AM EDTAreal Flood WarningOKXBronx, Kings, Nassau, New York, Queens, Richmond and 1 more7 hr
Sep 2, 3:50 AM EDTRip Current StatementOKXKings, Nassau, Queens, Suffolk16 hr
Sep 2, 4:38 AM EDTAreal Flood AdvisoryOKXNassau, Queens, Suffolk3 hr
Sep 2, 4:55 AM EDTAreal Flood AdvisoryOKXSuffolk3 hr
Sep 2, 5:01 AM EDTAreal Flood WarningOKXOrange, Putnam, Rockland, Westchester3 hr
Sep 2, 7:49 AM EDTAreal Flood AdvisoryOKXOrange, Putnam, Rockland, Westchester10 hr
Sep 2, 10:07 AM EDTAreal Flood WarningOKXPutnam, Rockland, Westchester15 hr
Sep 2, 10:16 AM EDTAreal Flood WarningOKXBronx, Nassau, Rockland, Westchester25 hr
Sep 2, 10:59 AM EDTSmall Craft AdvisoryOKX19 hr

Nearby

Flash Flood Warnings in New York, 2021Every flash flood warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.