Public Information Statement
Issued by NWS Denver/Boulder, CO

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NOUS45 KBOU 221214
PNSBOU

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE PUEBLO COLORADO
600 AM MDT WED APR 22 2009

...STRONG STRAIGHT LINE WINDS AND LARGE HAIL ARE MAJOR WEATHER
THREATS IN COLORADO...

ACROSS THE STATE OF COLORADO...MAINLY DURING THE WARM
SEASON...THUNDERSTORMS CAN DEVELOP BY MIDDAY AND CARRY ON INTO THE
EVENING HOURS.  AS MENTIONED EARLIER DURING THIS SEVERE WEATHER
AWARENESS WEEK...SOME THREATS FROM THUNDERSTORMS INCLUDE TORNADOES
AND FLOODING.

TORNADOES CAN BE THE FRONT PAGE HEADLINE IN NEWSPAPERS OR THE TOP
STORY ON RADIO OR TELEVISION NEWS IN COLORADO...BUT DAMAGING
STRAIGHT LINE WINDS OF TORNADO AND HURRICANE FORCE CAN ALSO INJURE
AND KILL ANIMALS AND HUMANS.  DOWNBURST WINDS FROM A THUNDERSTORM
USUALLY RESULT WHEN AN AREA WITHIN THE STORM IS QUICKLY COOLED BY
RAIN...HAIL...OR EVAPORATION. THIS POCKET OF COOLED AIR...HEAVIER
THAN THE SURROUNDING AIR...ACCELERATES DOWNWARD TO THE GROUND.  AS
THE COOL AIR SLAMS INTO THE GROUND...IT SPREADS OUT FROM THE AREA OF
IMPACT.  THIS PROCESS...IN EXTREME CASES...CAN CAUSE WINDS HIGHER
THAN 100 MPH.  WEATHER FORECASTERS CALL THESE BURSTS OF WIND
MICROBURSTS IF THEY ARE LESS THAN 2 1/2 MILES ACROSS AND MACROBURSTS
IF THEY ARE GREATER THAN 2 1/2 MILES ACROSS.

THESE DOWNBURSTS OF AIR CAN BE VERY HAZARDOUS AND EVEN
LIFE THREATENING TO PILOTS AND CAN CAUSE EXTENSIVE DAMAGE...INJURIES
AND FATALITIES AT GROUND LEVEL AS WELL. TRY TO GET INDOORS DURING
ALL THUNDERSTORM ACTIVITY.  HIGH WINDS CAN SUDDENLY DEVELOP...WHICH
CAN CAUSE THINGS ON THE GROUND TO BECOME SWIFT MOVING AIRBORNE
MISSILES...WHICH CAN INJURE OR KILL.

HAIL...ANOTHER THUNDERSTORM THREAT...OFTEN OCCURS IN COLORADO.
HAIL FORMS WITHIN THUNDERSTORMS AS LIQUID WATER FREEZES IN THE
COLD MID AND UPPER LEVELS OF THE STORMS.  THE HAILSTONES ARE KEPT
ALOFT BY STRONG UPDRAFT WINDS FOR A TIME...THEN WHEN THEY BECOME
TOO LARGE TO BE KEPT ALOFT BY THE UPDRAFTS...THEY CASCADE TO THE
GROUND.  HAILSTONES VARY FROM PEA SIZE...ABOUT 3/8 OF AN INCH IN
DIAMETER...TO LARGER THAN GRAPEFRUITS...NEARLY 5 INCHES IN
DIAMETER.

HAILSTONES CAN DO TREMENDOUS DAMAGE TO FARM CROPS...EITHER AS
LARGE HAILSTONES OR AS A CONCENTRATED FALL OF SMALL HAILSTONES
THAT ACCUMULATE TO A DEPTH OF SEVERAL INCHES.  LARGE HAIL CAN
EASILY DAMAGE VEHICLES AND BUILDINGS...AND CAN BE LIFE THREATENING
TO ANIMALS AND PEOPLE.  AGAIN...TRY TO GET INDOORS DURING ALL
THUNDERSTORMS.  A FALL OF SMALL HAIL CAN SUDDENLY CHANGE TO A FALL
OF VERY LARGE ICE MISSILES...THAT CAN INJURE OR KILL.

THE NATIONAL WEATHER SERVICE ISSUES SEVERE THUNDERSTORM WARNINGS FOR
WINDS OF 58 MPH OR HIGHER AND FOR LARGE HAIL ONE INCH IN DIAMETER OR
LARGER. REALIZE THAT SOME STORMS ARE CAPABLE OF MUCH LARGER HAIL AND
MUCH HIGHER WIND...SO WHEN YOU HEAR ABOUT A SEVERE THUNDERSTORM
WARNING...SEEK SHELTER.

WHEN THUNDERSTORMS...WITH ALL THEIR HAZARDS...THREATEN YOU THIS
SEVERE WEATHER SEASON...TUNE TO NOAA ALL HAZARDS WEATHER RADIO.
IN EACH PLACE YOU FIND YOURSELF DURING THREATENING WEATHER DAYS...
PLAN OUT THE ACTIONS YOU WOULD TAKE IF WEATHER WERE TO BECOME LIFE
THREATENING.  NOAAS NATIONAL WEATHER SERVICE WISHES YOU A SAFE
SEVERE WEATHER SEASON.

TOM MAGNUSON
WARNING COORDINATION METEOROLOGIST
NATIONAL WEATHER SERVICE
PUEBLO COLORADO








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