THE HYDROMETEOROLOGICAL PREDICTION CENTER

CAMP SPRINGS, MD


STORM SUMMARY MESSAGE



STORM SUMMARY NUMBER 1 FOR WESTERN U.S. WINTER STORM
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
100 AM PST WED JAN 18 2012
 
...THE ONSLAUGHT OF SUBTROPICAL PACIFIC MOISTURE IS SPREADING
MODERATE RAIN AND SNOW TO PORTIONS OF THE PACIFIC NORTHWEST...
 
A LARGE PORTION OF THE NORTHWESTERN U.S. HAS WINTER STORM WARNINGS
IN PLACE. THIS REGION SPANS AS FAR SOUTH AS EXTREME NORTHERN
CALIFORNIA AND AS FAR EAST AS SOUTH-CENTRAL MONTANA. EMBEDDED
WITHIN THIS EXPANSIVE AREA OF WARNINGS ARE WINTER WEATHER
ADVISORIES WHICH INCLUDES THE ENTIRE SIERRA NEVADA MOUNTAIN CHAIN.

IN ADDITION TO THE SNOW RELATED WARNINGS AND ADVISORIES...COASTAL
OREGON HAS A HURRICANE FORCE WIND WARNING IN PLACE IN ITS OFFSHORE
WATERS.
  
FOR A DETAILED GRAPHICAL DEPICTION OF THE LATEST
WATCHES...WARNINGS AND ADVISORIES...PLEASE SEE WWW.WEATHER.GOV

AT 1200 AM PST...THE LATEST NATIONAL WEATHER SERVICE DOPPLER
RADARS INDICATED AN EXPANSIVE AREA OF RAIN AND SNOW FALLING ALONG
THE WASHINGTON/OREGON BORDER. MODIFIED ARCTIC AIR ADVANCING INTO
THE REGION HAS ALLOWED TEMPERATURES TO APPROACH THE FREEZING MARK
OVER THE REGION. AS A RESULT...LOWER ELEVATIONS ARE CURRENTLY
EXPERIENCING LIGHT TO MODERATE SNOW INCLUDING THE CITY OF
PORTLAND...OR. FURTHER EAST...THERE IS A LULL IN THE PRECIPITATION
ACROSS THE LOWER ELEVATIONS WHILE LIGHT SNOW WAS FALLING OVER THE
BLUE MOUNTAINS OF NORTHEASTERN OREGON. TO THE SOUTH...A SEPARATE
BATCH OF MODERATE RAIN WAS CROSSING INTO EXTREME NORTHWESTERN
CALIFORNIA. 														AT THE SURFACE...THERE IS NO DISCERNIBLE
LOW PRESSURE AREA CROSSING THE REGION OF INTEREST. HOWEVER...AN
ARCTIC RIDGE OF HIGH PRESSURE DROPPING SOUTHWARD HAS ALLOWED A
CHANGEOVER TO SNOW OVER SOME OF THE LOWEST ELEVATIONS OF THE
PACIFIC NORTHWEST. FALLING PRECIPITATION HAS BEEN A RESULT OF THE
ACTIVE PLUME OF SUBTROPICAL MOISTURE STREAMING IN COMBINED WITH
MID-LEVEL ENERGY TRACKING TOWARD THE COAST.

...SELECTED STORM TOTAL SNOWFALL IN INCHES FROM 200 PM PST MON JAN
16 THROUGH 1200 AM PST WED JAN 18...

...IDAHO...
MULLAN                               15.0 ESTIMATED           
WALLACE                              14.0 ESTIMATED           
OSBURN                               13.5                     
PRICHARD                             12.0 ESTIMATED           
CLARK FORK SSE                        9.0                     
MOSCOW 5 NNE                          6.0 ESTIMATED           
SANDPOINT                             6.0                     

...MONTANA...
HERON 2 NW                           15.3                     
SALTESE 6 NW                         12.0                     
BABB 11 WSW                          10.0                     
TROY                                  6.0 ESTIMATED           

...OREGON...
MOUNT HOOD MEADOWS                   28.0                     
TIMBERLINE                           26.0 ESTIMATED           
LITTLE MEADOW SNOTEL                 19.0                     
DETROIT 1 ESE                        18.0                     
RED HILL SNOTEL                      18.0                     
BEAR GRASS SNOTEL                    16.0                     
BENNETT PASS                         16.0                     
BLAZED ALDER SNOTEL                  16.0                     
DALY LAKE SNOTEL                     16.0                     
WHITE RIVER                          16.0                     
WHITE RIVER SNOW PARK                16.0                     
CORVALLIS 3 NW                        4.0                     
DOWNTOWN PORTLAND                     1.0 ESTIMATED           

...WASHINGTON...
JUNE LAKE SNOTEL                     20.0                     
SHEEP CANYON SNOTEL                  17.0                     
SURPRISE LAKE SNOTEL                 17.0                     
TROUT LAKE 1 W                       17.0                     
SPENCER MEADOW SNOTEL                15.0                     
SWIFT CREEK SNOTEL                   15.0                     
PEPPER CREEK SNOTEL                  13.0                     
PLAIN 1 NW                           12.7                     
ARLINGTON 2 NNE                      10.0                     
CAMAS                                10.0                     
WHITE SALMON 4 ENE                   10.0                     
HURRICANE RIDGE 6 NW                  8.0                     

...SELECTED PEAK WIND GUSTS IN MILES PER HOUR EARLIER IN THE
EVENT...

...OREGON...
SUMMER LAKE 9 SSE                     64                     


THIS WILL BE A MULTI-DAY EVENT AS A SERIES OF MID-LEVEL
DISTURBANCES TRACK ACROSS THE EASTERN PACIFIC AND INTO THE WESTERN
U.S.. DURING THIS PERIOD OF TIME...LOW-LEVEL MOISTURE EXTENDING
BACK TOWARD THE SUBTROPICAL PACIFIC WILL CONTINUE TO FLOW INTO THE
NORTHWESTERN U.S. THE INTERACTION BETWEEN THIS ANOMALOUS MOISTURE
WITH THE MODIFIED ARCTIC AIR MASS AND LOCAL TOPOGRAPHY WILL LEAD
TO MODERATE TO HEAVY PRECIPITATION OVER THE REGION. THIS WILL EVEN
LEAD TO SNOW ACCUMULATIONS IN MANY OF THE LOWER ELEVATIONS.
COASTAL REGIONS OF NORTH-WESTERN CALIFORNIA AND WESTERN OREGON
COULD SEE RAINFALL TOTALS IN EXCESS OF 10 INCHES BY SATURDAY
MORNING...WITH INLAND SNOWS OVER THE HIGHER ELEVATIONS BETWEEN 5
AND 10 FEET. IN ADDITION TO THE HEAVY PRECIPITATION...HOWLING
WINDS ARE EXPECTED WITH HURRICANE FORCE GUSTS POSSIBLE ALONG THE
COAST OF OREGON.    

THE NEXT STORM SUMMARY WILL BE ISSUED BY THE HYDROMETEOROLOGICAL
PREDICTION CENTER AT 700 AM PST. PLEASE REFER TO YOUR LOCAL
NATIONAL WEATHER SERVICE OFFICE FOR ADDITIONAL INFORMATION ON THIS
EVENT.

RUBIN-OSTER




Last Updated: 402 AM EST WED JAN 18 2012