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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1150 AM CST SAT JAN 8 2011
...EXPERIMENTAL USE OF EXTREME COLD WARNING TO START MONDAY...
BEGINNING MONDAY...JANUARY 10 2011...AND CONTINUING THROUGH APRIL 15
2011...NATIONAL WEATHER SERVICE OFFICES BASED IN THE DAKOTAS AND
MINNESOTA...INCLUDING CHANHASSEN...WILL BEGIN ISSUING AN
EXPERIMENTAL EXTREME COLD WARNING.
OCCASIONALLY...TEMPERATURES FALL WELL BELOW ZERO WITH LITTLE OR NO
WIND. CURRENTLY THE ONLY WAY TO HEADLINE VERY COLD TEMPERATURES IS
WITH THE USE OF WIND CHILL ADVISORIES OR WARNINGS. THE EXPERIMENTAL
EXTREME COLD WARNING WILL BE ISSUED IN THE RARE SITUATIONS WHEN AIR
TEMPERATURES FALL TO DANGEROUS LEVELS BUT THERE IS LITTLE OR NO WIND.
EXTREME COLD WARNINGS WILL BE ISSUED AS NON PRECIPITATION WEATHER
PRODUCTS...NPW...AND WILL USE THE VALID TIME EVENT CODE EC.W FOR
DISSEMINATION.
THRESHOLDS...
WIND CHILL ADVISORY...WIND CHILLS 25 BELOW TO 34 BELOW.
WIND CHILL WARNING...WIND CHILLS 35 BELOW OR COLDER.
EXTREME COLD WARNING...AIR TEMPERATURES 35 BELOW OR COLDER WITH
LITTLE IF ANY WIND.
CAVEAT...
THERE MAY BE SOME INSTANCES WHERE AN EXTREME COLD WARNING IS
ISSUED WHEN AIR TEMPERATURES ARE BETWEEN 30 BELOW AND 34 BELOW.
TIME OF YEAR...LENGTH OF OCCURRENCE AND IMPACT WILL BE SOME OF THE
CONSIDERATIONS IN THESE CASES.
IN ALL OF THESE CASES THE ABOVE CRITERIA WOULD NEED TO BE MET OVER
A WIDESPREAD AREA...NOT AN ISOLATED LOCATION...AND FOR A
SIGNIFICANT AMOUNT OF TIME...AT LEAST SEVERAL HOURS.
They'll probably get to test it out next weekend.
