618
FOUS11 KWBC 230923
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
423 AM EST MON NOV 23 2009
VALID 12Z MON NOV 23 2009 - 12Z THU NOV 26 2009
DAY 1...
CASCADES...
SOME SNOW WILL LINGER IN THE COASTAL RANGES TODAY /MONDAY/ UNTIL
THE ONSHORE FLOW WEAKENS. UNTIL IT DOES...THERE IS A SLIGHT RISK
OF 4 INCHES OF ADDITIONAL SNOW MAINLY IN THE OROGRAPHICALLY
FAVORED WEST FACES OF THE WA RANGE.
WESTERN HIGH PLAINS...
A SHORT WAVE TROF KICKING EASTWARD OF THE CO/WY MOUNTAINS WILL
BRING SOME PCPN TO SWRN/SC NEB...PROBABLY STARTING OUT AS RAIN BUT
TRANSITIONING OVER TO SOME WET SNOW SHORTLY BEFORE PCPN ENDS.
WHILE SNOWFALL AMOUNTS SHOULD BE ON THE ORDER OF AN INCH OR
TWO...ENOUGH ENSEMBLE MEMBERS SUGGEST THAT THERE IS A LOW END
SLIGHT CHC OF SNOWFALL REACHING 4 OR MORE INCHES.
THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.
DAY 2...
THE PROBABILITY OF SIGNIFICANT ICING AND/OR HEAVY SNOW IS LESS
THAN 10 PERCENT.
DAY 3...
UPPER MIDWEST...
SFC LOW PRESSURE SHOULD DEVELOP OVER THE PLAINS ON DAY 2 AND THEN
MOVE NORTHEAST ACROSS THE CENTRAL PLAIS TOWARDS THE GREAT LAKES.
THE MODELS HAVE FINALLY COME INTO GENERAL AGREEMENT WITH THE IDEA
THAT PCPN SHOULD PRIMARILY FALL AS RAIN ON DAY 2 DUE TO A WARM
THERMAL PROFILE AND ONLY A SHORT PERIOD WHEN THE DYNAMICAL COOLING
ASSOCIATED WITH THE MID AN UPPER SYSTEM AND THE DEVELOPMENT OF A
DRY SLOT. STILL...THE TROF WILL CONTINUE TO MOVE EAST AND THE
MODELS STILL SUGGEST THAT RAIN WILL MIX WITH OR CHANGE TO SNOW
OVER PARTS OF THE UPPER MIDWEST LATE ON DAY 2 AND CONTINUE INTO
DAY 3 AS COLDER AIR FILTERS SOUTHWARD ON NORTHERLY WINDS BEHIND
THE DEPARTING SFC LOW. ONCE AGAIN...QPF SUGGESTS THAT AREAL
AVERAGE SNOWFALL AMOUNTS SHOULD BE ON THE ORDER OF AN INCH OR TWO
BUT ENOUGH ENSEMBLE MEMBERS POINT TO THE POSSIBILITY FOR SOME 4
INCH SNOWFALL AMOUNTS TO WARRANT A LOW END SLIGHT RISK ON DAY 3.
THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.
BANN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page