Severe Thunderstorm Watch 490

Issued

Jul 18, 2012, 12:20 PM EDT (16:20 UTC)

Expired

Jul 18, 2012, 9:00 PM EDT

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

60 kt

The Boston radar (KBOX), 86 km from the middle of the area, began a volume at 16:19 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

70%

• Mesoscale Discussion 1489Jul 18, 10:25 AM EDT
• Mesoscale Discussion 1492Jul 18, 2:46 PM EDT
• Mesoscale Discussion 1496Jul 18, 4:50 PM EDT

659 
WWUS20 KWNS 181621
SEL0
SPC WW 181621
CTZ000-MAZ000-NJZ000-NYZ000-RIZ000-CWZ000-190100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 490
NWS STORM PREDICTION CENTER NORMAN OK
1220 PM EDT WED JUL 18 2012

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

       CONNECTICUT
       MASSACHUSETTS
       NORTHEAST NEW JERSEY
       SOUTHEAST NEW YORK
       RHODE ISLAND
       COASTAL WATERS

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1220 PM UNTIL
900 PM EDT.

HAIL TO 1.5 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 70
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES NORTHEAST
OF NEW BEDFORD MASSACHUSETTS TO 40 MILES NORTH NORTHWEST OF
NEWARK NEW JERSEY.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

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.

DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THIS AFTERNOON AHEAD OF COLD FRONT SETTLING SWD INTO THE
REGION.  WARM SECTOR HAS BECOME QUITE HOT...WHICH WHEN COMBINED WITH
DEWPOINTS IN THE 60S TO LOWER 70S...IS RESULTING IN MLCAPE OF
2000-3000+ J/KG.  WHEN COUPLED WITH 30-40 KT OF DEEP...WLY
SHEAR...SETUP WILL FAVOR ORGANIZED STORM MODES CAPABLE OF DAMAGING
WINDS AND LARGE HAIL.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 30020.


...MEAD

Severe Thunderstorm Watches in New York, 2012Severe Thunderstorm Watches in Massachusetts, 2012Severe Thunderstorm Watches in Connecticut, 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.