Heavy Snow in Washington, December 23, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
935 PM PST FRI DEC 22 2006

.SYNOPSIS...HOLIDAY TRAVELERS SHOULD PREPARE FOR SNOWY DRIVING
CONDITIONS THIS WEEKEND. A STORM SYSTEM WILL BRING LIGHT TO
MODERATE SNOW ACCUMULATIONS TO MUCH OF THE INLAND NORTHWEST
SATURDAY AND SATURDAY EVENING. ANOTHER STORM SYSTEM WILL SPREAD
PRECIPITATION ACROSS THE REGION SUNDAY NIGHT AND CHRISTMAS DAY.

&&

.DISCUSSION...
REST OF TONIGHT AND SATURDAY...FOR THE REST OF THIS EVENING A
MAINLY STATIC WEATHER REGIME FEATURING WIDESPREAD LOW CLOUDS AND
POCKETS OF FOG. EXPECTED LOW TEMPERATURES WILL LIKELY BOTTOM OUT
OVER THE NEXT FEW HOURS AND REMAIN STEADY THROUGH THE REMAINDER OF
THE NIGHT. HEAVY HIGH CLOUDS NOTED ON SATELLITE WILL PREVENT
SIGNIFICANT FURTHER COOLING. ALL IN ALL A RATHER QUIET...CALM AND
SOMEWHAT MURKY NIGHT.

THE NEXT STORM SYSTEM CLEARLY IDENTIFIABLE ON SATELLITE CLOSING IN
ON THE COAST THIS EVENING. THIS IS A BROAD OCCLUDED FRONTAL REGION
WITH AREAS OF DYNAMIC SUPPORT MAINLY HEADED NORTH AND SOUTH OF THE
FORECAST AREA. IN THE ZONE BETWEEN THESE ENERGY FIELDS...HIGH
CONFIDENCE EXISTS FOR A 6 HOUR PERIOD OF LIGHT TO MODERATE
ISENTROPICALLY GENERATED SNOW AT MOST LOCATIONS STARTING IN THE
PRE-DAWN HOURS OVER THE CASCADES AND WESTERN BASIN...ABOUT SUNRISE
OVER THE EASTERN ZONES AND LASTING WELL INTO THE AFTERNOON OVER
THE IDAHO PANHANDLE. WHILE THIS SYSTEM IS MOIST WITH A GOOD
FRONTAL FOCUSING MECHANISM...THE SPEED WITH WHICH IT WILL
PROPAGATE THROUGH THE REGION WILL LIKELY KEEP ACCUMULATION AMOUNTS
BELOW WARNING CRITERIA...EXCEPT FOR LOCALIZED TERRAIN INFLUENCED
POCKETS MAINLY OVER THE IDAHO PANHANDLE. HAVE DECIDED TO CONTINUE
RUNNING WITH THE CURRENT BROAD BRUSHED SNOW ADVISORY AT THIS
TIME. EXPECT WIDESPREAD 2 TO 4 INCHES AT BASIN LOCATIONS...LOW END
OF THIS RANGE OVER GRANT COUNTY AND THE PALOUSE REGION...HIGH END
IN THE NORTHERN ZONES INCLUDING SPOKANE/CDA...AND HIGH END WITH
POCKETS OF 6 INCHES IN VALLEYS NORTH OF COEUR DALENE. ZONE UPDATE
IMMINENT TO REFLECT THESE CHANGES. NO UPDATE TO STATE FORECAST
NEEDED AT THIS TIME. /FUGAZZI

&&

.AVIATION...
FORECAST DOMINATED BY INCOMING WINTER OCCLUDED FRONT WHICH WILL
BEGIN TO IMPACT THE CASCADES AND WESTERN COLUMBIA BASIN BY 12Z WITH
WIDESPREAD IFR CIELINGS AND VIS IN SNOW...WITH MODERATE IMPROVEMENT
TO MVFR CIG/VIS SCATTERED SNOW SHOWERS AFTER 18Z THROUGH 06Z SUNDAY.
OVER THE EASTERN COLUMBIA BASIN AND IDAHO PANHANDLE...WIDESPREAD IFR
CIG AND VIS SNOW WILL BEGIN AROUND 15Z WITH MODERATE IMPROVEMENT TO
SCATTERED MVFR SNOW SHOWERS OVER THE EASTERN BASIN AFTER 20Z. IDAHO
PANHANDLE WILL REMAIN MOSTLY IFR CIG/VIS IN NUMEROUS SNOW SHOWERS
WITH EXTENSIVE MOUNTAIN OBSCURATIONS FROM 17Z THROUGH 06Z SUNDAY.
/MJF

&&

.PRELIMINARY POINT TEMPS/POPS...
SPOKANE        23  32  23  32  26  31 /  10  80  80   0  60  60
COEUR DALENE  25  32  25  32  24  31 /  10 100  80   0  60  60
PULLMAN        25  35  26  34  30  35 /  10  90  80   0  60  60
LEWISTON       27  40  30  40  31  40 /  10  90  70   0  50  60
COLVILLE       20  30  22  33  20  32 /  10  80  80   0  70  50
SANDPOINT      21  29  25  34  18  32 /  10 100  80   0  60  70
KELLOGG        23  29  25  32  21  32 /  10 100  80  10  50  70
MOSES LAKE     25  32  23  32  26  31 /  10  70  20   0  70  40
WENATCHEE      23  29  24  30  25  32 /  20  90  10   0  70  40
OMAK           22  29  20  28  22  30 /  20  90  20   0  80  40

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...SNOW ADVISORY FROM 7 AM SATURDAY TO MIDNIGHT PST SATURDAY NIGHT
     FOR CENTRAL PANHANDLE MOUNTAINS...COEUR DALENE AREA...
     IDAHO PALOUSE...NORTHERN PANHANDLE.

WA...SNOW ADVISORY FROM 7 AM SATURDAY TO MIDNIGHT PST SATURDAY NIGHT
     FOR NORTHEAST MOUNTAINS...OKANOGAN HIGHLANDS...SPOKANE
     AREA...WASHINGTON PALOUSE.

     SNOW ADVISORY FROM 4 AM TO 4 PM PST SATURDAY FOR MOSES LAKE
     AREA...OKANOGAN VALLEY...UPPER COLUMBIA BASIN...WATERVILLE
     PLATEAU...WENATCHEE AREA.

     SNOW ADVISORY FROM 4 AM TO 4 PM PST SATURDAY FOR EAST SLOPES
     NORTHERN CASCADES.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SPOKANE WA
1224 PM PST FRI DEC 22 2006

IDZ001>004-WAZ033>038-041>044-232030-
NORTHERN PANHANDLE-COEUR DALENE AREA-IDAHO PALOUSE-
CENTRAL PANHANDLE MOUNTAINS-WASHINGTON PALOUSE-MOSES LAKE AREA-
UPPER COLUMBIA BASIN-SPOKANE AREA-NORTHEAST MOUNTAINS-
OKANOGAN HIGHLANDS-WENATCHEE AREA-EAST SLOPES NORTHERN CASCADES-
OKANOGAN VALLEY-WATERVILLE PLATEAU-
INCLUDING THE CITIES OF...SANDPOINT...RATHDRUM...BONNERS FERRY...
PRIEST RIVER...COEUR DALENE...POST FALLS...HAYDEN...MOSCOW...
ST. MARIES...KELLOGG...PINEHURST...OSBURN...WALLACE...MULLAN...
PULLMAN...MOSES LAKE...EPHRATA...OTHELLO...QUINCY...RITZVILLE...
COULEE DAM...ODESSA...ELECTRIC CITY...WILBUR...GRAND COULEE...
COULEE CITY...SPOKANE...COLVILLE...DEER PARK...CHEWELAH...
NEWPORT...KETTLE FALLS...REPUBLIC...INCHELIUM...WENATCHEE...
LEAVENWORTH...MAZAMA...TWISP...WINTHROP...OMAK...OKANOGAN...
BREWSTER...BRIDGEPORT...OROVILLE...WATERVILLE...MANSFIELD
1224 PM PST FRI DEC 22 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH
IDAHO...CENTRAL WASHINGTON...EAST CENTRAL WASHINGTON...NORTH
CENTRAL WASHINGTON...NORTHEAST WASHINGTON AND SOUTHEAST
WASHINGTON.

THE FOLLOWING WATCHES WARNINGS OR ADVISORIES ARE CURRENTLY IN EFFECT
   SNOW ADVISORY IN EFFECT FROM 7 AM SATURDAY TO MIDNIGHT PST
     SATURDAY NIGHT FOR NORTH IDAHO PANHANDLE...COEUR D ALENE
     AREA...IDAHO PALOUSE...CENTRAL PANHANDLE
     MOUNTAINS...WASHINGTON PALOUSE...SPOKANE AREA...NORTHEAST
     MOUNTAINS...OKANOGAN HIGHLANDS
   SNOW ADVISORY IN EFFECT FROM 4 AM TO 4 PM PST SATURDAY FOR
     MOSES LAKE AREA...UPPER COLUMBIA BASIN...WENATCHEE
     AREA...EAST SLOPES NORTH CASCADES...OKANOGAN
     VALLEY...WATERVILLE PLATEAU

PLEASE SEE THE FOLLOWING PRODUCTS FOR MORE INFORMATION.
   SEAWSWOTX  /WWUS46 KOTX/

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A FAST-MOVING PACIFIC STORM SYSTEM IS EXPECTED TO MOVE INTO THE
AREA SATURDAY AND PRODUCE LIGHT TO MODERATE SNOWFALL AND
SNOW ACCUMULATION. ANOTHER SYSTEM IS EXPECTED TO BRING PACIFIC
MOISTURE INTO THE AREA SUNDAY NIGHT INTO MONDAY WITH PRECIPITATION
STARTING OUT AS SNOW FOR MOST LOCATIONS...HOWEVER WITH WARMER AIR
ENCROACHING...SNOW MAY MIX WITH OR CHANGE TO RAIN FOR A BRIEF
PERIOD FOR MANY OF THE LOWER ELEVATIONS DURING THE DAY ON
CHRISTMAS.

IDZ026-027-WAZ031-032-232030-
LEWISTON AREA-LEWIS AND SOUTHERN NEZ PERCE COUNTIES-
NORTHEAST BLUE MOUNTAINS-LOWER GARFIELD AND ASOTIN COUNTIES-
INCLUDING THE CITIES OF...LEWISTON...KAMIAH...CRAIGMONT...
NEZPERCE...WINCHESTER...ANATONE...PEOLA...CLARKSTON
1224 PM PST FRI DEC 22 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
IDAHO AND SOUTHEAST WASHINGTON.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A FAST-MOVING PACIFIC STORM SYSTEM IS EXPECTED TO MOVE INTO THE
AREA SATURDAY WITH THE POTENTIAL FOR ACCUMULATING SNOWFALL IN MANY
AREAS. A SECOND SYSTEM WILL MOVE TOWARD THE AREA FOR SUNDAY NIGHT
AND CHRISTMAS DAY BRINGING SNOW BACK INTO THE AREA FOR SUNDAY
NIGHT...HOWEVER THE PRECIPITATION MAY MIX WITH OR CHANGE TO RAIN
IN THE LOWER ELEVATIONS FOR A BRIEF PERIOD DURING THE DAY ON
CHRISTMAS.