PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
900 AM EDT MON MAR 30 2009

...SEVERE WEATHER AWARENESS WEEK FROM MARCH 29TH THROUGH APRIL 4TH...

GOVERNOR JENNIFER GRANHOLM HAS DECLARED MARCH 29TH THROUGH APRIL 4TH AS SEVERE WEATHER AWARENESS WEEK IN MICHIGAN.  EACH DAY THIS WEEK... THE NATIONAL WEATHER SERVICE...IN CONJUNCTION WITH THE MICHIGAN COMMITTEE FOR SEVERE WEATHER AWARENESS...WILL ISSUE PUBLIC INFORMATION STATEMENTS ABOUT THE HAZARDS OF SEVERE
THUNDERSTORMS...TORNADOES...AND FLOODING.

TODAY WE DISCUSS SOME TERMS YOU MAY HEAR ASSOCIATED WITH SEVERE
WEATHER. ONE IMPORTANT NOTE FOR 2009 IS THE CHANGE IN THE SEVERE
THUNDERSTORM HAIL CRITERION.  ON APRIL 1ST...2009...THE CRITERION
WILL CHANGE FROM 3/4 OF AN INCH IN DIAMETER TO 1 INCH IN DIAMETER.
FOR MORE INFORMATION ON THIS CHANGE PLEASE CONTACT YOUR LOCAL
NATIONAL WEATHER SERVICE OFFICE.

TORNADO...A VIOLENTLY ROTATING COLUMN OF AIR TRAILING FROM A   THUNDERSTORM AND IN CONTACT WITH THE GROUND.

FUNNEL CLOUD...A VIOLENTLY ROTATING COLUMN OF AIR TRAILING FROM A THUNDERSTORM BUT NOT IN CONTACT WITH THE GROUND.

SEVERE THUNDERSTORM... A THUNDERSTORM THAT PRODUCES ONE OR MORE OF THE FOLLOWING...  WINDS OF 58 MILES AN HOUR OR GREATER... HAIL 1 INCH IN DIAMETER OR LARGER... OR A TORNADO.

DOWNBURST... A SMALL AREA OF RAPIDLY DESCENDING AIR BENEATH A   THUNDERSTORM. A DOWNBURST CAN CAUSE DAMAGING WINDS IN EXCESS   OF 100 MILES AN HOUR.  ALSO KNOWN AS STRAIGHT-LINE WINDS.

FLOOD... AN INUNDATION OF A NORMALLY DRY AREA CAUSED BY AN INCREASED WATER LEVEL IN AN ESTABLISHED WATERCOURSE... SUCH AS A RIVER... STREAM... OR DRAINAGE DITCH.

FLASH FLOOD... A FLOOD THAT QUICKLY INUNDATES AN AREA FROM LOCALLY HEAVY RAINFALL. USUALLY... FLOODING WILL OCCUR WITHIN JUST 30 to 60 MINUTES AND UP TO A FEW HOURS.

TORNADO/SEVERE THUNDERSTORM WATCH... CONDITIONS ARE FAVORABLE   FOR THE DEVELOPMENT OF TORNADOES AND/OR SEVERE THUNDERSTORMS    IN AND CLOSE TO THE WATCH AREA. WATCHES ARE NORMALLY ISSUED FOR    4 TO 6 HOURS... AND COVER LARGE GEOGRAPHICAL AREAS... SUCH AS A PART OF A STATE OR SEVERAL STATES. REMAIN ALERT FOR APPROACHING   STORMS AND MONITOR THE WEATHER CLOSELY FOR POSSIBLE WARNINGS.

SEVERE THUNDERSTORM WARNING... ISSUED WHEN SEVERE WEATHER IS  IMMINENT.  WARNINGS INDICATE IMMINENT DANGER TO LIFE AND PROPERTY TO THOSE IN THE PATH OF THE STORM. SEVERE THUNDERSTORM WARNINGS ARE NORMALLY ISSUED AS A STORM BASED WARNING USING COUNTIES AND CITIES AS REFERENCES. THESE WARNINGS ARE USUALLY ISSUED FOR AROUND AN HOUR. WHEN THE WEATHER BECOMES THREATENING... MOVE QUICKLY TO YOUR PRE-DESIGNATED PLACE OF SAFETY.

TORNADO WARNING... A TORNADO IS IMMINENT. TORNADO WARNINGS ARE   NORMALLY ISSUED AS A STORM BASED WARNING USING COUNTIES AND CITIES AS REFERENCES. THESE WARNINGS ARE USUALLY ISSUED FOR AN HOUR OR LESS. IF A TORNADO WARNING IS ISSUED FOR YOUR AREA AND THE WEATHER IS THREATENING...MOVE QUICKLY TO YOUR PRE-DESIGNATED PLACE OF SAFETY.

FLASH FLOOD OR FLOOD WATCH... ISSUED WHENEVER FLASH FLOODING OR   FLOODING IS POSSIBLE WITHIN THE DESIGNATED WATCH AREA. BE ALERT.

FLASH FLOOD OR FLOOD WARNING... ISSUED WHENEVER FLASH FLOODING OR  FLOODING HAS BEEN REPORTED OR IS IMMINENT. TAKE PRECAUTIONS AT ONCE.

ON TUESDAY WE WILL DISCUSS THE UPCOMING SEVERE WEATHER DRILLS
SCHEDULED FOR WEDNESDAY...APRIL 1ST.

FOR MORE INFORMATION...CONTACT YOUR NEAREST NATIONAL WEATHER
SERVICE OFFICE...OR YOUR LOCAL EMERGENCY MANAGEMENT AGENCY.

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