601 
FXUS01 KWBC 230820
PMDSPD
 
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
319 AM EST MON NOV 23 2009
 
VALID 12Z MON NOV 23 2009 - 00Z WED NOV 25 2009
 
THIS WEEK WILL CONSIST OF A CHANGE IN THE WEATHER PATTERN WHICH
HAD BEEN FEATURING A STORM TRACK PREDOMINANTLY THROUGH THE PACIFIC
NORTHWEST AND INTO THE UPPER INTERMOUNTAIN WEST. AN UPPER RIDGE
HAS DEVELOPED ACROSS THE WESTERN U.S. WHICH HAS FORCED A BULK OF
THE UPPER ENERGY INTO WESTERN CANADA. CONSEQUENTLY...THE HEAVIER
AXES OF PRECIPITATION WHICH BEEN IMPACTING THE OLYMPICS AND
CASCADES THE PAST COUPLE OF WEEKS WILL SHIFT INTO COASTAL BRITISH
COLUMBIA. THEREAFTER...THE DISTURBANCES WILL RIDE UP OVER AND THE
RIDGE AND INTO THE PLAINS WHERE A BULK OF THE PRECIPITATION WILL
BE FOUND TO START THE WEEK.

ONE SUCH SYSTEM HAS ALREADY MADE ITS WAY INTO THE CENTRAL ROCKIES
WHICH IS STILL PRODUCING SCATTERED SNOW SHOWERS FROM THE NORTHERN
ROCKIES SOUTHWARD INTO WYOMING AND COLORADO. AS A LARGE SURFACE
HIGH PRESSURE AREA BUILDS ACROSS THE CENTRAL GREAT BASIN...THESE
SNOWS WILL COME TO AN END BY MONDAY EVENING. AS THE DISTURBANCE
ADVANCES EASTWARD...IT WILL ENCOUNTER AN INCREASE IN MOISTURE
CONTENT PROVIDED BY THE GULF OF MEXICO. AS A RESULT...EXPECT AN
INCREASE IN COVERAGE OF LIGHT TO MODERATE RAIN SHOWERS ACROSS THE
CENTRAL PLAINS AND INTO THE MIDDLE MISSISSIPPI VALLEY BY LATE
MONDAY NIGHT AND INTO TUESDAY. ON THE BACK SIDE OF THIS
SYSTEM...TEMPERATURES MAY BE COOL ENOUGH TO SUPPORT A MIXTURE OF
RAIN AND SNOW WITH ONLY MINIMAL AMOUNTS EXPECTED. BESIDES THE
FORECAST OF PRECIPITATION...THE ASSOCIATED FRONTAL BOUNDARY WITH
THIS SYSTEM WILL BRING A MUCH DRIER AIR MASS INTO THE CENTRAL U.S.
HOWEVER...ONLY MINIMAL DROPS IN TEMPERATURE ARE TO BE EXPECTED
GIVEN THE PACIFIC ORIGIN OF THIS WEATHER SYSTEM.

ELSEWHERE...A COASTAL SYSTEM RIDING UP THE EASTERN SEABOARD WILL
GENERALLY PARALLEL THE COASTLINE BRINGING SHOWERS AND
THUNDERSTORMS FROM THE CAROLINAS NORTHWARD INTO THE LOWER NEW
ENGLAND STATES. THE HEAVIEST ACTIVITY IS EXPECTED TO HUG THE
COASTLINE WITH THE BIGGEST IMPACTS ACROSS THE OUTER
BANKS...DELMARVA PENINSULA...AND EVENTUALLY OVER CAPE COD.

LOOKING BACK WEST...THE LARGE DOME OF HIGH PRESSURE FORECAST TO
SETTLE OVER THE CENTRAL GREAT BASIN WILL BRING A SERIES OF
COLD...DRY NIGHTS TO MUCH OF THE INTERIOR WEST THROUGH THE MIDDLE
OF THE WEEK. WIDESPREAD LOWS IN THE TEENS AND 20S ARE TO BE
EXPECTED...ALTHOUGH ABUNDANT SUNSHINE DURING THE DAYTIME WILL
RAISE TEMPERATURES BACK INTO THE 40S. THE OTHER EFFECT OF THIS
HIGH PRESSURE AREA WILL BE THE OFFSHORE WINDS EXPECTED ACROSS MUCH
OF THE SOUTHWESTERN U.S.


RUBIN-OSTER


GRAPHIC AVAILABLE AT WWW.HPC.NCEP.NOAA.GOV
$$