Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL0
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 480...CORRECTED
NWS STORM PREDICTION CENTER NORMAN OK
230 AM EST WED AUG 7 2013
CORRECTED TO CHANGE EST TO EDT
THE NWS STORM PREDICTION CENTER HAS ISSUED A
* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHERN LOWER MICHIGAN
LAKE HURON
LAKE MICHIGAN
* EFFECTIVE THIS WEDNESDAY MORNING FROM 230 AM UNTIL 1000 AM EDT.
* PRIMARY THREATS INCLUDE...
SEVERAL SIGNIFICANT DAMAGING WIND GUSTS TO 80 MPH POSSIBLE
A FEW LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES EAST
NORTHEAST OF TRAVERSE CITY MICHIGAN TO 30 MILES SOUTH OF ROBEN
HOOD MICHIGAN. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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 478...WW 479...
DISCUSSION...A WELL-DEVELOPED SQUALL-LINE WILL MOVE QUICKLY
EASTWARD ACROSS LOWER MICHIGAN EARLY THIS MORNING. STRONG DEEP
LAYER SHEAR...MODERATE INSTABILITY AND A WELL-DEFINED LOW TO
MID-LEVEL JET STRUCTURE BEHIND THE SYSTEM WILL RESULT IN A WIND
DAMAGE THREAT AS THE LINE MOVES ACROSS LOWER MICHIGAN.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 28055.
...BROYLES
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW0
WW 480 SEVERE TSTM MI LH LM 070630Z - 071400Z
AXIS..85 STATUTE MILES EAST AND WEST OF LINE..
35ENE TVC/TRAVERSE CITY MI/ - 30S RQB/ROBEN HOOD MI/
..AVIATION COORDS.. 75NM E/W /31ENE TVC - 25ENE MKG/
HAIL SURFACE AND ALOFT..1.5 INCHES. WIND GUSTS..70 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 28055.
LAT...LON 44908318 43278380 43278719 44908666
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU0.
Watch 480 Status Report Message has not been issued yet.
Note:
Click for Complete Product Text.
Tornadoes
Probability of 2 or more tornadoes
|
Low (10%)
|
Probability of 1 or more strong (F2-F5) tornadoes
|
Low (5%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (50%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (50%)
|
Hail
Probability of 10 or more severe hail events
|
Low (20%)
|
Probability of 1 or more hailstones > 2 inches
|
Low (<5%)
|
Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
|
High (70%)
|
For each watch, probabilities for particular events inside the watch
(listed above in each table) are determined by the issuing forecaster.
The "Low" category contains probability values ranging from less than 2%
to 20% (F2-F5 tornadoes), less than 5% to 20% (all other probabilities),
"Moderate" from 30% to 60%, and "High" from 70% to greater than 95%.
High values are bolded and lighter in color to provide awareness of
an increased threat for a particular event.
weather.gov 
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