Severe Thunderstorm Watch 489

Issued

Jul 17, 2012, 1:23 PM EDT (17:23 UTC)

Expired

Jul 17, 2012, 9:00 PM EDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Burlington radar (KCXX), 66 km from the middle of the area, began a volume at 17:26 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.

Two or more tornadoes

20%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 1480Jul 17, 12:02 PM EDT
• Mesoscale Discussion 1484Jul 17, 3:32 PM EDT
• Mesoscale Discussion 1487Jul 17, 6:30 PM EDT

696 
WWUS20 KWNS 171724
SEL9
SPC WW 171724
MEZ000-NHZ000-NYZ000-VTZ000-180100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 489
NWS STORM PREDICTION CENTER NORMAN OK
125 PM EDT TUE JUL 17 2012

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

       WESTERN MAINE
       NEW HAMPSHIRE
       NORTHERN NEW YORK
       VERMONT

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 125 PM UNTIL
900 PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES SOUTHWEST
OF WATERTOWN NEW YORK TO 40 MILES EAST SOUTHEAST OF BERLIN NEW
HAMPSHIRE.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 488...

DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THIS AFTERNOON AHEAD OF COLD FRONT ADVANCING SEWD INTO THE
REGION.  THE COMBINATION OF STEEPENING MIDLEVEL LAPSE RATES FROM THE
W AND BOUNDARY LAYER DEWPOINTS IN THE 60S WILL YIELD MLCAPE VALUES
APPROACHING 1000-1500 J/KG.  WHEN COUPLED WITH A STEADILY
STRENGTHENING WLY...DEEP-LAYER WIND FIELD...SETUP WILL SUPPORT
SUPERCELLS AND BOWING STRUCTURES CAPABLE OF DAMAGING WINDS...LARGE
HAIL...AND PERHAPS A TORNADO.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 32030.


...MEAD

Severe Thunderstorm Watches in New York, 2012Severe Thunderstorm Watches in Vermont, 2012Severe Thunderstorm Watches in New Hampshire, 2012Every severe thunderstorm watch in 2012

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.