Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 76, NWS New York, NY

September 1, 2021Nassau County, New York

NWS New York, NY issued this severe thunderstorm warning at Sep 1, 2021, 10:44 PM EDT for Nassau County, New York. It was in force for 46 min. 4 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
Sep 1, 2021, 10:44 PM EDT (02:44 UTC)
Expired
Sep 1, 2021, 11:30 PM EDT
In force
46 min
Issued by
NWS New York, NY
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

County Nassau County, NY

The radar

The Brookhaven radar (KOKX), 68 km from the middle of the area, began a volume at 02:47 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 1, 11:27 PM EDTTSTM WND DMG1 Sw Jericho, NYNORTHERN STATE PARKWAY WESTBOUND IS CLOSED AT EXIT 34 DUE TO FLOODING.
Sep 1, 11:28 PM EDTTSTM WND DMG1 Ese Jericho, NYTREE DOWN ON THE NORTHERN STATE PARKWAY WESTBOUND BETWEEN EXIT 27N AND EXIT 26 N.
Sep 1, 11:28 PM EDTTSTM WND DMG1 Nw Manhasset Hills, NYTREE DOWN ON NORTHERN STATE PARKWAY WESTBOUND BETWEEN EXIT 27 N- SHELTER ROCK ROAD AND EXIT 26 N - NEW HYDE PARK ROAD.
Sep 1, 11:28 PM EDTTSTM WND DMG1 S Westbury, NYTREE DOWN ON MEADOWBROOK STATE PARKWAY SOUTHBOUND AT EXIT M3 - STEWART AVENUE.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 1, 6:22 PM EDTTornado WatchSPC7 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 2.7 hours before the alert went out and 68 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.

280 
WUUS51 KOKX 020244
SVROKX
NYC059-020330-
/O.NEW.KOKX.SV.W.0076.210902T0244Z-210902T0330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New York NY
1044 PM EDT Wed Sep 1 2021

The National Weather Service in Upton NY has issued a

* Severe Thunderstorm Warning for...
  Nassau County in southeastern New York...

* Until 1130 PM EDT.

* At 1043 PM EDT, severe thunderstorms were located along a line
  extending from Elmont to 9 miles south of Rockaway Beach, moving
  northeast at 25 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and power lines.

* Severe thunderstorms will be near...
  Valley Stream and Lynbrook around 1050 PM EDT.
  Garden City and Mineola around 1055 PM EDT.
  Levittown and Westbury around 1105 PM EDT.
  Long Beach and Farmingdale around 1110 PM EDT.
  Plainview around 1115 PM EDT.
  Syosset and Oceanside around 1120 PM EDT.
  Oyster Bay and Jones Beach around 1125 PM EDT.
  Freeport and Massapequa around 1130 PM EDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 100 AM EDT for southeastern
New York.

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

A Tornado Watch remains in effect until 100 AM EDT for southeastern
New York.

&&

LAT...LON 4057 7376 4059 7376 4059 7374 4061 7375
      4065 7374 4065 7372 4069 7373 4073 7371
      4074 7370 4075 7371 4077 7370 4090 7348
      4088 7347 4087 7346 4080 7345 4060 7342
      4057 7357
TIME...MOT...LOC 0243Z 221DEG 20KT 4069 7370 4045 7378 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

NV

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, 10:47 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, 11:13 PM EDTFlash Flood WarningOKXSuffolk6 hr
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

Severe Thunderstorm Warnings in New York, 2021Every severe thunderstorm 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.