433
FXUS66 KOTX 161345
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
545 AM PST MON DEC 16 2024
SYNOPSIS
LIGHT SNOW WILL SPREAD ACROSS THE REGION THIS MORNING. A WETTER
WEATHER SYSTEM IS EXPECTED TUESDAY INTO TUESDAY NIGHT WITH RISING
SNOW LEVELS. SNOW WILL MAINLY ACCUMULATE OVER HIGH MOUNTAINS AND
IN NORTH-CENTRAL WASHINGTON INCLUDING THE EASTERN CASCADE
VALLEYS. THIS WET SYSTEM WILL BE FOLLOWED BY BREEZY WINDS
WEDNESDAY AFTERNOON. THE REST OF THE WEEK WILL FEATURE MILD
TEMPERATURES AND INTERMITTENT LIGHT PRECIPITATION PRIMARILY
CONFINED TO THE NORTHERN MOUNTAINS.
DISCUSSION
TODAY THROUGH TUESDAY: LIGHT SNOW HAS STARTED ACROSS PORTIONS OF
THE CASCADES. THE RADAR IS BEGINNING TO FILL ACROSS SOUTHERN WA
AND PRECIPITATION WILL SPREAD NORTH AND EAST THROUGH THE MORNING
HOURS. SNOW WILL BEGIN ACROSS THE WEST PLAINS BTWN 8 AND 9, WITH
SNOW BEGINNING ACROSS SPOKANE GENERALLY AFTER 9AM. SNOW AMOUNTS
HAVEN'T CHANGED FROM WHAT WAS FORECASTED YESTERDAY. WIDESPREAD
VALLEY TOTALS OF 1 TO 2 INCHES, WITH SOME LOCALLY HIGHER AMOUNTS
TO 3 INCHES ACROSS PORTIONS OF CENTRAL WA GIVEN THE UPSLOPE FLOW.
THE MOUNTAINS WILL SEE SLIGHTLY MORE SNOW WITH A 55% CHANCE OF
STEVENS PASS SEEING 4 INCHES OF SNOW, AND A 40% CHANCE FOR
LOOKOUT PASS.
MODELS ARE INDICATING THE PRECIPITATION MAY END A BIT SOONER THAN
PREVIOUSLY THOUGHT. HAVE MADE SOME MODIFICATIONS TO ENDING THE
ADVISORIES A FEW HOURS EARLIER FOR PORTIONS OF THE COLUMBIA
BASIN/OKANOGAN HIGHLANDS AND EASTERN WA AND THE ID PANHANDLE.
PRECIPITATION WANES DURING THE EVENING, BUT OVERNIGHT PRECIPITATION
WILL MOVE ONCE AGAIN INTO THE REGION AS THE BACKSIDE OF THE
TROUGH MOVES INTO THE REGION. PRECIP WILL TAKE A SIMILAR PATH
MOVING SOUTHWEST TO NORTHEAST THROUGH THE OVERNIGHT HOURS AND
THROUGH TUESDAY. SNOW WILL BE MOSTLY CONFINED TO THE CASCADES,
CASCADE VALLEYS AND OVER THE WATERVILLE PLATEAU, OKANOGAN VALLEY
AND NORTHERN WA AND THE ID PANHANDLE. CURRENT FORECAST HAS AN INCH
OR LESS FOR THE VALLEYS IN THESE LOCATIONS. LITTLE TO NO SNOW IS
FORECAST FOR THE COLUMBIA BASIN, SPOKANE/COEUR D'ALENE AREA,
PALOUSE AND LC VALLEY. /NISBET
TUESDAY NIGHT THROUGH MONDAY: THE REGION WILL REMAIN UNDER A STEADY
STREAM OFF OF WEAK SHORTWAVES WIDESPREAD SHOWERS ACROSS THE INLAND
NORTHWEST. ENSEMBLES ARE IN DECENT AGREEMENT OF THE OVERALL PATTERN
BUT DIFFER ON TIMING AND AMOUNT OF MOISTURE ASSOCIATED WITH THE
WAVES. THE FIRST WAVE IS EXPECTED OVERNIGHT TUESDAY INTO WEDNESDAY.
SOUTHWEST FLOW WILL LEAD TO WARMER AIR MOVING INTO THE REGION. THE
WARMER AIR WILL LEAD TO PRECIP TYPE TO BECOME MAINLY LOW LAND RAIN
AND MOUNTAIN SNOW. ENTRENCHED COLD AIR CASCADE VALLEYS IS EXPECTED
TO LEAD TO SOME POCKETS OF FREEZING RAIN WEDNESDAY MORNING AS THE
PRECIP TYPES SWITCHES FROM SNOW TO RAIN. ACCUMULATIONS ARE NOT
EXPECTED TO EXCEED A TENTH OF AN INCH. PROBABILITIES OF GREATER THAN
A TENTH RANGE FROM 20 TO 40% FOR THE CASCADE VALLEYS AND PORTIONS OF
THE WATERVILLE PLATEAU. STEVENS PASS CAN EXPECT 8 TO 12 INCHES OF
SNOW WITH THIS WAVE. AFTERNOON WINDS ARE EXPECTED TO GET BREEZY FOR
THE BASIN BEHIND THIS WAVE. MODELS HAVE STEADILY BEEN INCREASING
THEM FROM RUN TO RUN. SUSTAINED SOUTHWEST WINDS IN THE TEENS AND LOW
20S WITH GUSTS AROUND 40 MPH ARE POSSIBLE.
THE REST OF THE PERIOD PRECIP TOTALS ARE EXPECTED TO BE AROUND A
TENTH OF AN INCH OR LESS PER 24 HOUR PERIOD THROUGH THE WEEKEND.
ANOTHER DECENT SYSTEM IS EXPECTED TO IMPACT THE REGION STARTING ON
MONDAY LASTING THROUGH WEDNESDAY. IT WILL CONTINUE TO BE A MOUNTAIN
SNOW AND VALLEY RAIN SETUP WITH SOUTHWEST FLOW PATTERN. HIGHS FOR
THE PERIOD WILL BE IN THE 30S TO LOW 40S. LOWS WILL BE IN THE 20S TO
LOW 30S. /JDC
AVIATION
12Z TAFS: -SN IS MOVING ACROSS CENTRAL WA AND THE COLUMBIA BASIN.
GIVEN THE UPSLOPE FLOW INTO THE CASCADES, THERE COULD BE PERIODS
OF MODERATE SNOW THROUGH THE MORNING HOURS. -SN WILL BE TO THE
SPOKANE AREA AND PALOUSE BTWN 15-18Z. EXPECT SNOW TO BE LIGHT,
BUT DETERIORATING CONDITIONS TO IFR WITH THE SNOW. THIS EVENING
LOW CLOUDS AND FOG COULD DEVELOP AFTER PRECIP ENDS AT
GEG/SFF/MWH/EAT.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: THERE IS MODERATE
CONFIDENCE ON IFR WITH SNOW ON MONDAY. CONFIDENCE REMAINS MODERATE
TO HIGH THAT WIDESPREAD FOG OR LOW STRATUS WITH IFR/LIFR
CONDITIONS PREVAILING ACROSS MUCH OF THE REGION AS SNOW ENDS INTO
MONDAY EVENING.
-----------------------
CONFIDENCE DESCRIPTORS:
LOW - LESS THAN A 30 PERCENT CHANCE
MODERATE - 30 TO 70 PERCENT CHANCE
HIGH - GREATER THAN A 70 PERCENT CHANCE
FOR ADDITIONAL PROBABILISTIC INFORMATION FOR NWS SPOKANE AIRPORTS,
PLEASE REFER TO THE AVIATION DASHBOARD ON OUR WEBPAGE:
HTTPS:/WWW.WEATHER.GOV/OTX/AVNDASHBOARD
PRELIMINARY POINT TEMPS/POPS
SPOKANE 34 31 37 35 46 31 / 90 50 60 90 80 10
COEUR D'ALENE 34 30 37 35 45 32 / 90 70 60 90 90 10
PULLMAN 35 29 37 35 45 32 / 90 60 60 80 80 10
LEWISTON 40 34 43 40 53 36 / 60 50 50 60 50 10
COLVILLE 32 23 34 29 42 26 / 70 30 60 90 90 10
SANDPOINT 34 28 35 34 42 31 / 90 60 60 90 100 20
KELLOGG 34 31 37 36 43 33 / 90 80 70 90 90 30
MOSES LAKE 37 32 38 35 45 30 / 80 50 50 70 50 10
WENATCHEE 35 29 35 34 43 31 / 90 40 60 80 60 10
OMAK 32 27 34 32 36 28 / 90 20 50 90 70 10
OTX WATCHES/WARNINGS/ADVISORIES
ID...WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 5 PM PST THIS
AFTERNOON FOR COEUR D'ALENE AREA-IDAHO PALOUSE-NORTHERN
PANHANDLE.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 7 AM PST
TUESDAY FOR CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 5 PM PST THIS
AFTERNOON FOR NORTHEAST MOUNTAINS-SPOKANE AREA-WASHINGTON
PALOUSE.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 1 PM PST THIS
AFTERNOON FOR OKANOGAN HIGHLANDS-UPPER COLUMBIA BASIN.
WINTER WEATHER ADVISORY UNTIL 1 PM PST THIS AFTERNOON FOR
CENTRAL CHELAN COUNTY-OKANOGAN VALLEY-WATERVILLE PLATEAU-
WENATCHEE AREA-WESTERN CHELAN COUNTY-WESTERN OKANOGAN
COUNTY.
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