Alert archive / New York / Severe Thunderstorm Watches in 1999

Severe Thunderstorm Watch 521

July 4, 199914 counties in New York

The Storm Prediction Center issued this severe thunderstorm watch at Jul 4, 1999, 3:00 AM EDT for 14 counties in New York. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jul 4, 1999, 3:00 AM EDT (07:00 UTC)
Expired: Jul 4, 1999, 7:00 AM EDT
In force: 4 hr
Issued by: the Storm Prediction Center

Counties Albany County, NY, Fulton County, NY, Hamilton County, NY, Herkimer County, NY, Lewis County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Warren County, NY

The radar

The Ft Drum radar (KTYX), 73 km from the middle of the area, began a volume at 07:03 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.

Warnings issued inside it

5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jul 4, 3:05 AM EDT	Severe Thunderstorm Warning	BGM	Madison	65 min
Jul 4, 3:36 AM EDT	Severe Thunderstorm Warning	BGM	Otsego	64 min
Jul 4, 4:37 AM EDT	Severe Thunderstorm Warning	ALY	Albany, Schenectady, Schoharie	118 min
Jul 4, 6:17 AM EDT	Flash Flood Warning	ALY	Fulton, Herkimer, Montgomery	6 hr
Jul 4, 6:41 AM EDT	Flash Flood Warning	BGM	Oneida	2 hr

The nearest sounding before it

Albany, NY (KALY), launched 00:00Z, 7.0 hours before the alert went out and 119 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: 169 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 1650 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 124 m²/s²
0-3 km storm-relative helicity: 237 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

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

504 
WWUS9 KMKC 040642
SEL1  
MKC WW 040642
NYZ000-041100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 521
STORM PREDICTION CENTER NORMAN OK
242 AM EDT SUN JUL 4 1999

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   CENTRAL AND EASTERN NEW YORK                           

EFFECTIVE THIS SUNDAY MORNING FROM 300 AM UNTIL 700 AM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 55 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 30 MILES WEST NORTHWEST OF UTICA NEW
YORK TO 20 MILES SOUTH SOUTHEAST OF GLENS FALLS NEW YORK.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...  CONTINUE...WW 520...

DISCUSSION...SHORT LINE OF THUNDERSTORMS OVER EXTREME ERN LAKE
ONTARIO IS MOVING 45 KT...AND RADIAL VELOCITY DATA FROM FT DRUM
RADAR INDICATE POTENTIAL FOR DAMAGING WIND GUSTS.  NEW CELLS ARE
ALSO DEVELOPNG NEAR SRN END OF LINE SUGGESTING ESEWD PROPAGATION TO
SYSTEM.


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450.  MEAN STORM
MOTION VECTOR 27040.


...WEISS

440,0755 435,0732 421,0732 423,0755

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 3, 8:45 PM EDT	Severe Thunderstorm Watch	SPC	Albany, Chenango, Columbia, Delaware, Dutchess, Greene and 10 more	4 hr

Nearby

Severe Thunderstorm Watches in New York, 1999 Every severe thunderstorm watch in 1999

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.