Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 36, NWS New York, NY

August 28, 2021Suffolk County, New York

NWS New York, NY issued this flash flood warning at Aug 28, 2021, 5:00 AM EDT for Suffolk County, New York. It was in force for 95 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 28, 2021, 5:00 AM EDT (09:00 UTC)
Expired: Aug 28, 2021, 6:35 AM EDT
In force: 95 min
Issued by: NWS New York, NY
Area: Storm-based polygon
Flood severity: None

County Suffolk County, NY

The radar

The Brookhaven radar (KOKX), 12 km from the middle of the area, began a volume at 09:00 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 00:00Z, 9.0 hours before the alert went out and 12 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2057 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 1094 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 13 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

770 
WGUS51 KOKX 280900
FFWOKX
NYC103-281100-
/O.NEW.KOKX.FF.W.0036.210828T0900Z-210828T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New York NY
500 AM EDT Sat Aug 28 2021

The National Weather Service in Upton has issued a

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

* Until 700 AM EDT.

* At 500 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2.5 and 3.5 inches of 
  rain have fallen. The expected rainfall rate is 2 to 3 inches in 1 
  hour. 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...
  Centereach, Shirley, Medford, Manorville, Middle Island, Port 
  Jefferson, Wading River, Center Moriches, Westhampton, Coram, 
  Mastic, Farmingville, Rocky Point, Mastic Beach, Mount Sinai, 
  Yaphank, Brookhaven National Laboratory, East Patchogue, Selden 
  and Setauket.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4095 7314 4096 7314 4096 7304 4097 7303
      4098 7286 4081 7259 4071 7293 4071 7294
      4073 7295 4088 7310 4089 7310 4089 7311

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...2-3 INCHES IN 1 HOUR

$$

JP

1 follow-up statement

890 
WGUS71 KOKX 281035
FFSOKX

Flash Flood Statement
National Weather Service New York NY
635 AM EDT Sat Aug 28 2021

NYC103-281045-
/O.CAN.KOKX.FF.W.0036.000000T0000Z-210828T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Suffolk NY-
635 AM EDT Sat Aug 28 2021

...FLASH FLOOD WARNING IS CANCELLED FOR WESTERN SUFFOLK COUNTY...

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

LAT...LON 4095 7314 4096 7314 4096 7304 4097 7303
      4098 7286 4081 7259 4071 7293 4071 7294
      4073 7295 4088 7310 4089 7310 4089 7311

$$

JP

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 28, 2:57 AM EDT	Areal Flood Advisory	OKX	Suffolk	43 min
Aug 28, 3:40 AM EDT	Flash Flood Warning	OKX	Suffolk	3 hr
Aug 28, 4:25 AM EDT	Areal Flood Advisory	OKX	Suffolk	2 hr
Aug 28, 5:48 AM EDT	Areal Flood Advisory	OKX	Kings, Nassau, Queens, Suffolk	117 min
Aug 28, 1:49 PM EDT	Areal Flood Advisory	OKX	Suffolk	86 min
Aug 28, 3:24 PM EDT	Areal Flood Advisory	OKX	Nassau, Suffolk	81 min

Nearby

Flash Flood Warnings in New York, 2021 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.