Tornado Watch 78

Issued

Mar 27, 2007, 12:35 PM CDT (17:35 UTC)

Expired

Mar 27, 2007, 10:00 PM CDT

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

60 kt

The Shreveport radar (KSHV), 112 km from the middle of the area, began a volume at 17:35 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

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 351Mar 27, 11:58 AM CDT
• Mesoscale Discussion 353Mar 27, 2:48 PM CDT
• Mesoscale Discussion 355Mar 27, 4:25 PM CDT
• Mesoscale Discussion 356 Tornado watch 78Mar 27, 6:56 PM CDT

000
WWUS20 KWNS 271735
SEL8  
SPC WW 271735
ARZ000-LAZ000-TXZ000-280100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 78
NWS STORM PREDICTION CENTER NORMAN OK
1235 PM CDT TUE MAR 27 2007

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

       SOUTHWEST AND SOUTH CENTRAL ARKANSAS
       NORTHWEST LOUISIANA
       EXTREME NORTHEAST TEXAS

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 1235 PM UNTIL
800 PM CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTHWEST OF
SHREVEPORT LOUISIANA TO 50 MILES EAST NORTHEAST OF EL DORADO
ARKANSAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

DISCUSSION...A CLUSTER OF TSTMS HAS SHOWN EMBEDDED SUPERCELL
STRUCTURES ACROSS EXTREME NE TX DURING THE PAST HOUR...WHILE OTHER
STORMS ARE FORMING IN A SEPARATE CLUSTER IN SW AR.  THE SHV VWP
REVEALS A NARROW CORRIDOR WITH FAVORABLE VERTICAL SHEAR FOR
SUPERCELLS...AND IT APPEARS THERE IS SOME ORGANIZATION TO THE STORM
CLUSTERS ON THE MESOSCALE.  WITH GRADUAL DESTABILIZATION CONTINUING
ACROSS AR/NRN LA IN ADVANCE OF THE STORMS...THERE IS THE POTENTIAL
FOR THE ISOLATED TORNADO AND DAMAGING WIND/HAIL THREAT TO PERSIST
THROUGH THE AFTERNOON ACROSS NW LA INTO SW AR.  ADDITIONALLY...MORE
ISOLATED TSTMS WILL DEVELOP ACROSS E TX AND SPREAD NEWD INTO WRN LA
ALONG THE INSTABILITY AXIS.  THE PRIMARY THREAT WITH THESE STORMS
WILL BE ISOLATED LARGE HAIL AND DAMAGING GUSTS.

AVIATION...TORNADOES AND 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 24025.


...THOMPSON

Tornado Watches in Arkansas, 2007Tornado Watches in Louisiana, 2007Tornado Watches in Texas, 2007Every tornado watch in 2007

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.