638
FXUS66 KOTX 200543
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
943 PM PST THU DEC 19 2024
SYNOPSIS
A RIDGE OF HIGH PRESSURE WILL RESULT IN A DRYING TREND AND CALMER
WINDS THROUGH FRIDAY WITH A RETURN OF AREAS OF STRATUS AND FOG.
UNSETTLED WEATHER WILL RETURN THIS WEEKEND AND CONTINUE INTO
NEXT WEEK. MILD TEMPERATURES WILL RESULT IN PRECIPITATION
FALLING PRIMARILY AS VALLEY RAIN AND MOUNTAIN SNOW. CHECK
MOUNTAIN PASS FORECASTS AND CONDITIONS OFTEN BEFORE TRAVELING.
UPDATE
UPDATED THE FORECASTED TO REFLECT THE BAND OF LIGHT RAIN MOVING
ACROSS EASTERN WASHINGTON AND NORTH IDAHO THIS EVENING. /VMT
AVIATION
06Z TAFS: BRIEF LIGHT RAIN IS CURRENTLY MOVING ACROSS EASTERN
WASHINGTON AND NORTH IDAHO. THIS WILL MOISTEN THE BOUNDARY LAYER
AND MAY ALLOW FOR PATCHY FOG AND LOW CEILINGS TO RETURN TONIGHT AS
A LAYER OF DRY AIR ALOFT MOVES IN BEHIND THE PRECIPITATION. MVFR
CONDITIONS WILL BE COMMON FOR THE CASCADE VALLEYS AND THE COLUMBIA
BASIN AFTER 10Z. THERE IS A 50 PERCENT CHANCE FOR VISIBILITY TO
DROP BELOW A HALF MILE IN THE COLUMBIA BASIN, INCLUDING MWH. THE
CLEARING BEHIND THIS BAND OF PRECIP MAY BE ENOUGH FOR STRATUS
AND/OR SHALLOW FOG TO DEVELOP INTO THE SPOKANE/CDA AREAS AND THE
NORTHERN VALLEYS AS WELL, BUT CONFIDENCE IS LOWER.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
THERE IS MODERATE CONFIDENCE FOR IFR CONDITIONS AT MWH BETWEEN
10-14Z. THERE IS A 30 PERCENT CHANCE FOR MVFR CONDITIONS TO
DEVELOP AT GEG, SFF,COE AFTER 14Z.
-----------------------
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
PREV DISCUSSION
/ISSUED 415 PM PST THU DEC 19 2024/
SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL RESULT IN A DRYING TREND AND CALMER
WINDS THROUGH FRIDAY WITH A RETURN OF AREAS OF STRATUS AND FOG.
UNSETTLED WEATHER WILL RETURN THIS WEEKEND AND CONTINUE INTO
NEXT WEEK. MILD TEMPERATURES WILL RESULT IN PRECIPITATION
FALLING PRIMARILY AS VALLEY RAIN AND MOUNTAIN SNOW. CHECK
MOUNTAIN PASS FORECASTS AND CONDITIONS OFTEN BEFORE TRAVELING.
DISCUSSION...
TONIGHT THROUGH SATURDAY NIGHT: AFTER A FEW DAYS OF ACTIVE WEATHER,
THE PACNW WILL SEE A BREAK. A RIDGE WILL BRING DRY, WARM CONDITIONS
TO MOST AREAS, THOUGH THE CASCADES WILL BE THE EXCEPTION. ENSEMBLES
WANT TO PUSH MOISTURE UP THE WESTERN SIDE OF THE RIDGE, WHICH WILL
BRING A SLIGHT CHANCE OF PRECIPITATION TO THE MOUNTAINS. THE
PRECIPITATION IS EXPECTED TO START AS A WINTERY MIX, BUT WITH WARM
AIR FROM THE SOUTH, SNOW LEVELS WILL RISE THROUGHOUT THE DAY,
TRANSITIONING THE PRECIPITATION TO BE MAINLY RAIN. ADDITIONAL SNOW
ACCUMULATIONS IN THE AREA ARE EXPECTED TO BE AROUND 1 INCH. THE MAIN
CONCERN FOR THE REST OF THE REGION WILL BE THE MORNING CONDITIONS IN
THE BASIN AND VALLEYS, WHERE PATCHY FOG AND STRATUS HAVE A POTENTIAL
TO FORM. HIGHS WILL BE ABOUT 10 DEGREES ABOVE NORMAL IN THE 30S AND
40S, WITH OVERNIGHT LOWS IN THE 20S TO LOW 30S.
WARM, SOUTHWESTERLY FLOW WILL DOMINATE, WITH A RIDGE TO THE EAST
OVER THE CENTRAL US. A SERIES OF SHORTWAVES WILL MOVE UP THE WEST
SIDE IN THE RIDGE, BRINGING SEVERAL ROUNDS OF WIDESPREAD
PRECIPITATION TO THE INLAND NW STARTING THIS WEEKEND. /KM
SUNDAY THROUGH THURSDAY:
WE START GETTING INTO A MORE ACTIVE WEATHER PATTERN BY SUNDAY
AFTERNOON WHICH CONTINUES INTO THE MIDDLE OF NEXT WEEK.FOR SUNDAY,NOW
LEVELS WILL BE LOWEST AROUND 2500 FEET IN THE NORTHERN CASCADE
EAST SLOPES FOR POTENTIALLY MIXED SNOW AND RAIN IN THE UPPER
STEHEKIN METHOW VALLEYS. VALLEYS ELSEWHERE IT'S EXPECTED TO BE
MAINLY VALLEY RAIN AS THIS WEATHER SYSTEM IS ON THE WARM SIDE FOR
WINTER. THE MOIST WEATHER SYSTEM WILL MOST STRONGLY IMPACT THE
CASCADES WITH NEAR 6 INCHES OF SNOW AT STEVENS PASS BY MONDAY
MORNING.
AFTER A BREAK BETWEEN STORMS ANOTHER STORM SYSTEM MONDAY NIGHT
INTO TUESDAY TAKES A SIMILAR TRAJECTORY COMING IN FROM THE
SOUTHWEST SPREADING RAIN AND MOUNTAINS SNOW FROM WEST TO EAST. THE
CASCADES AGAIN WILL SEE THE BRUNT OF THE MOUNTAIN SNOW WITH
STEVENS PASS GETTING ANOTHER 6 OR SO INCHES. SHERMAN PASS RAMPS
UP A BIT WITH NEAR 5 INCHES AS OF THIS FORECAST. LOOKOUT PASS
STILL DOESN'T GET A WHOLE LOT OF SNOW AS SNOW LEVELS REMAIN
PRETTY HIGH FOR THE CENTRAL PANHANDLE MOUNTAINS.
YET ANOTHER WEATHER SYSTEM MOVES IN LATE ON CHRISTMAS DAY AND
THIS ONE HAS A MUCH WETTER SIGNATURE. SNOW LEVELS AT THIS POINT
WOULD START OUT SIMILAR TO OTHER STORMS BUT THERE ARE SOME
INDICATIONS FOR HEAVIER SNOW TO STEVENS PASS IN PARTICULAR WHICH
MAY CAUSE DIFFICULTIES GETTING OVER THE CASCADES ON HIGHWAY 2
TOWARD THE LATTER PART OF NEXT WEEK THURSDAY AND FRIDAY. TYPICAL
UNCERTAINTIES COME WITH THIS TREND IN THAT THERE IS UNCERTAINTY IN
THE WAVE PATTERN AND HOW MUCH COLD AIR CAN LOWER SNOW LEVELS TO
THE VALLEYS. IF THE WAVE PATTER SHIFTS THEN POTENTIAL SNOW AMOUNTS
COULD CHANGE. THERE IS A NON-ZERO PROBABILITY OF SIGNIFICANT
SNOW FOR STEVENS PASS DURING THE WEDNESDAY NIGHT THURSDAY
TIMEFRAME SO IT'S GOOD TO KNOW STEVENS PASS MAY NOT BE THE BEST
TRAVEL ROUTE AFTER THE CHRISTMAS HOLIDAY. TC
PRELIMINARY POINT TEMPS/POPS
SPOKANE 33 43 32 44 34 43 / 20 10 0 60 70 10
COEUR D'ALENE 34 44 33 44 35 42 / 20 10 10 50 90 10
PULLMAN 36 46 35 46 33 42 / 10 0 0 60 70 10
LEWISTON 39 51 37 49 36 50 / 10 0 0 40 50 10
COLVILLE 29 40 28 40 32 42 / 30 10 10 60 80 20
SANDPOINT 32 41 31 42 34 40 / 40 10 10 40 90 20
KELLOGG 37 46 37 47 37 41 / 30 10 10 50 90 20
MOSES LAKE 31 43 32 42 33 43 / 0 10 0 80 20 30
WENATCHEE 34 41 33 40 32 37 / 0 10 10 80 20 40
OMAK 32 40 31 40 33 40 / 20 10 10 70 40 30
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page