Alert archive / New York / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 75, NWS New York, NY

September 7, 2012Rockland County, Westchester County, New York; Bergen County, New Jersey

NWS New York, NY issued this severe thunderstorm warning at Sep 7, 2012, 4:35 PM EDT for Rockland County, Westchester County, New York; Bergen County, New Jersey. It was in force for 22 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
Sep 7, 2012, 4:35 PM EDT (20:35 UTC)
Expired
Sep 7, 2012, 4:57 PM EDT
In force
22 min
Issued by
NWS New York, NY
Area
Storm-based polygon

Counties Bergen County, NJ, Rockland County, NY, Westchester County, NY

The radar

The Brookhaven radar (KOKX), 84 km from the middle of the area, began a volume at 20:36 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 12:00Z, 8.6 hours before the alert went out and 84 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 2012-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1099 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 2012-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
1099 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1017 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

329 
WUUS51 KOKX 072035
SVROKX
NJC003-NYC087-119-072130-
/O.NEW.KOKX.SV.W.0075.120907T2035Z-120907T2130Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NEW YORK NY
435 PM EDT FRI SEP 7 2012

THE NATIONAL WEATHER SERVICE IN UPTON NY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTCHESTER COUNTY IN SOUTHEAST NEW YORK...
  EASTERN BERGEN COUNTY IN NORTHEAST NEW JERSEY...
  ROCKLAND COUNTY IN SOUTHEAST NEW YORK...

* UNTIL 530 PM EDT...

* AT 432 PM EDT...TRAINED WEATHER SPOTTERS REPORTED A SEVERE
  THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS STORM
  WAS LOCATED NEAR NORWOOD...OR NEAR TAPPAN...AND MOVING EAST AT 10
  MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  TARRYTOWN...DOBBS FERRY...YONKERS...BRONXVILLE...WHITE PLAINS...
  SCARSDALE...PORT CHESTER...NEW ROCHELLE AND HARRISON

LAT...LON 4107 7401 4104 7368 4100 7365 4088 7377
      4090 7385 4091 7385 4090 7386 4095 7406
TIME...MOT...LOC 2035Z 283DEG 8KT 4098 7395

$$

JMC
1 follow-up statement
090 
WWUS51 KOKX 072057
SVSOKX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW YORK NY
457 PM EDT FRI SEP 7 2012

NJC003-NYC087-119-072105-
/O.CAN.KOKX.SV.W.0075.000000T0000Z-120907T2130Z/
ROCKLAND NY-BERGEN NJ-WESTCHESTER NY-
457 PM EDT FRI SEP 7 2012

...THE SEVERE THUNDERSTORM WARNING FOR WESTCHESTER...EAST CENTRAL
BERGEN AND ROCKLAND COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED. THE WARNING HAS 
THEREFORE BEEN CANCELLED.

LAT...LON 4107 7401 4104 7368 4100 7365 4088 7377
      4090 7385 4091 7385 4090 7386 4095 7406
TIME...MOT...LOC 2055Z 283DEG 8KT 4097 7389

$$

JMC

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 4:15 PM EDTSmall Craft AdvisoryOKX4 days
Sep 7, 4:43 PM EDTSpecial Marine WarningOKX32 min
Sep 7, 4:53 PM EDTSpecial Weather StatementOKXWestchester52 min
Sep 7, 4:59 PM EDTSpecial Weather StatementOKXBronx46 min
Sep 7, 5:43 PM EDTSpecial Weather StatementOKXWestchester62 min
Sep 7, 4:30 PM EDTAreal Flood AdvisoryOKXBergen60 min

Nearby

Severe Thunderstorm Warnings in New York, 2012Severe Thunderstorm Warnings in New Jersey, 2012Every severe thunderstorm warning in 2012

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.