258  
FXUS66 KOTX 091312  
AFDOTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SPOKANE WA  
512 AM PST FRI DEC 9 2022  
   
SYNOPSIS
 
 
ONE WEATHER SYSTEM WILL MOVE OUT OF NORTH IDAHO TODAY AS ANOTHER  
ONE MOVES INTO THE CASCADES LATER THIS AFTERNOON. MODERATE TO  
HEAVY SNOW IS LIKELY FRIDAY NIGHT INTO SATURDAY FOR CENTRAL  
WASHINGTON AND PARTS OF NORTHEAST WASHINGTON AS WELL. NEXT WEEK  
WILL FEATURE VERY COLD TEMPERATURES ACROSS THE INLAND NORTHWEST.  
 

 
   
DISCUSSION
 
 
TODAY THROUGH SATURDAY NIGHT : RADAR SHOWS SNOW CONTINUING ACROSS  
THE IDAHO PANHANDLE THIS MORNING. THE MAIN BAND OF SNOW WILL BE  
OUT OF IDAHO LATE THIS MORNING, BUT THERE COULD STILL BE SOME  
MOUNTAIN SHOWERS THROUGH THE AFTERNOON. THE NEXT WEATHER SYSTEM  
WILL MOVE ONTO THE WEST COAST THIS AFTERNOON AND BRING MODERATE TO  
HEAVY SNOW AMOUNTS TO PARTS OF CENTRAL AND NORTHEAST WASHINGTON.  
SNOW WILL BEGIN IN THE CASCADES BY THE LATE AFTERNOON AND THEN  
SPREAD EAST THROUGH THE EVENING HOURS. WITH THE LOW OFFSHORE, THIS  
WILL PROVIDE GOOD UPSLOPE FLOW INTO THE CASCADES. HREF MODEL AND  
SPC SREF IS POINTING AT AN INCH AN HOUR RATES FOR THE CASCADES  
TONIGHT. THE HEAVY SNOW WILL BE FOCUSED IN THE CASCADES TONIGHT,  
AND THEN TRANSITION SATURDAY TO PARTS OF CENTRAL AND NE WA. THE  
FOCUS OF HIGHEST QPF AND THEREFORE SNOWFALL IS CENTERED AROUND THE  
HIGHWAY 2 CORRIDOR FROM SPOKANE WESTWARD ONTO THE WATERVILLE  
PLATEAU. THE DIFFICULT PART OF THE FORECAST IS HOW FAR NORTH  
POSSIBLE WARM AIR WILL REACH. THIS IS THE BIG QUESTION FOR THE  
SPOKANE AREA. THE EC IS THE MOST BULLISH, WHEREAS THE GFS KEEPS  
SPOKANE ALL SNOW. NAM CHANGES SPOKANE OVER TO RAIN AROUND NOON  
SATURDAY. DO HAVE MENTION IN THE AFTERNOON OF A RAIN/SNOW MIX OR  
JUST PLAIN RAIN.  
 
SNOW AMOUNTS WILL VARY BY LOCATION, WITH CENTRAL WA INTO NE WA AND  
PARTS OF NORTH ID SEEING THE MOST. HAVE UPGRADED THE WATCHES TO  
WARNINGS. THE MOUNTAINS COULD SEE 10 TO 20 INCHES WITH THE VALLEYS  
SEEING 4 TO 10 INCHES. THE NUMBERS VARY BY LOCATION, WITH  
LOCATIONS ALONG THE RIVERS LIKELY SEEING THE LOWER END. THE  
HIGHWAY 2 CORRIDOR FROM SPOKANE WESTWARD WILL VARY AS  
WELL...SEEING 3 TO 10 INCHES WITH 3 INCHES FOR SPOKANE WHERE WE  
COULD TRANSITION TO RAIN BRIEFLY SATURDAY, AND UPWARDS OF 10  
INCHES OR MORE FOR WATERVILLE ON THE WATERVILLE PLATEAU. THE I-90  
CORRIDOR SOUTHWEST OF SPOKANE WILL SEE LIGHTER AMOUNTS...GENERALLY  
1 TO 3 INCHES. SOMETHING TO WATCH WILL BE SNOW ON THE PALOUSE.  
SOME OF THE HIGH RES MODELS AS WELL AS THE NAM BRINGS A LOT OF QPF  
TO THAT AREA SATURDAY MORNING. CURRENTLY HAVE 3-4 INCHES FOR  
PULLMAN, BUT ACCUMULATIONS COULD BE HIGHER IF THE WARM AIR IS SLOW  
TO MAKE IT THERE, AS WELL AS IF PRECIP AMOUNTS ARE HIGHER THAN  
WHAT WE CURRENTLY HAVE. /NISBET  
 
SUNDAY THROUGH FRIDAY: THE DEEP UPPER LEVEL LOW CONTINUES TO  
SLIDE SOUTHWARD LEAVING THE NORTHWEST IN A DEFORMATION ZONE  
BETWEEN A WEAK TROUGH IN NORTHERN BRITISH COLUMBIA AND A  
STRENGTHENING RIDGE IN ALASKA. ENSEMBLES WILL PUSH THAT RIDGE INTO  
BC AS WE START THE NEW WORK WEEK WITH OUR COLD LOW MOVING SOUTH  
AND EAST. WHAT'S INTERESTING IS THE RIDGE BEGINS TO EVOLVE AND  
BECOMES CENTERED OVER JUNEAU, AK WHICH WILL TURN THE MEAN FLOW OUT  
OF THE NORTH FOR THE PACIFIC AND INLAND NORTHWEST.  
 
THIS OPEN DOOR FOR NORTHERLY FLOW WILL BEGIN MONDAY AND CONTINUE  
THROUGH THE WEEK. WHILE THE FORECAST LOOKS RATHER DRY AFTER SUNDAY  
EVENING, WITH PRECIPITABLE WATER 40-60% OF NORMAL TUE-THU, CLOUD  
COVER SHOULD BE MUCH LESS BY MID WEEK. GIVEN THE CURRENT SNOWCOVER  
ON THE GROUND AND MORE ANTICIPATED FOR THE COMING SATURDAY STORM,  
OUR TEMPERATURES WILL LIKELY TAKE A NOSE DIVE NEXT WEEK. RIGHT  
NOW THE NBM GIVES SPOKANE A 60% PROBABILITY OF SEEING MIN  
TEMPERATURES TUESDAY BELOW 20F. THE LOW END FORECAST OF 14F FOR A  
LOW IS THE 10TH PERCENTILE FOR BOTH THE 4.0 AND 4.1 VERSION OF  
NBM. CPC PROBABILISTIC OUTLOOK IS ON BOARD AS WELL WITH A HIGH  
RISK OF MUCH BELOW NORMAL TEMPERATURES. FOR A REFERENCE, OMAK'S  
NORMAL LOW TEMPERATURE IS 24F, SPOKANE IS 25F. SPEAKING OF OMAK,  
THE NBM GIVES A 15% PROBABILITY OF SEEING A LOW TEMPERATURE  
TUESDAY OF 10F OR COLDER.  
 
SUFFICE TO SAY, NEXT WEEK LOOKS DRY AND SNOW-FREE, HOWEVER IT WILL  
BE VERY COLD WITH OUR SNOW ON THE GROUND AND SOME CLEAR, CLOUD-FREE  
DAYS FROM MID-WEEK INTO LATE WEEK. /DEWEY  
 

 
   
AVIATION
 
 
12Z TAFS: KMWH/KEPH/KEAT WILL SEE VLIFR VIS AND CIGS WITH  
IMPROVEMENTS AFT 18Z FOR KEAT. NOT AS CONFIDENT IN IMPROVEMENTS  
FOR KEPH & KMWH. THEY MAY REMAIN IN VLIFR UNTIL THE SNOW BEGINS  
AFT 03Z. SNOW MOVES INTO THE CASCADES AFT 00Z AND WILL SPREAD  
EASTWARD THROUGH THE NIGHT...REACHING KGEG/KSFF/KCOE/KPUW BTWN  
08-10Z. SNOWFALL INTENSITY WILL BE HEAVY AT TIMES OVERNIGHT IN  
THE CASCADES.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SPOKANE 31 25 35 27 35 21 / 10 80 100 40 30 10  
COEUR D'ALENE 32 24 34 28 36 22 / 20 50 90 60 20 10  
PULLMAN 32 24 35 27 35 25 / 20 60 100 20 30 20  
LEWISTON 37 30 42 32 39 31 / 10 50 70 20 40 30  
COLVILLE 29 20 33 24 38 14 / 0 80 90 60 20 10  
SANDPOINT 31 25 31 28 35 23 / 20 60 100 70 30 10  
KELLOGG 32 24 36 30 37 26 / 60 30 80 60 40 20  
MOSES LAKE 31 24 36 26 35 17 / 10 100 90 30 30 10  
WENATCHEE 27 23 32 27 35 24 / 10 100 100 30 30 10  
OMAK 27 22 32 28 35 20 / 10 100 90 40 20 0  
 

 
   
OTX WATCHES/WARNINGS/ADVISORIES
 
 
ID...WINTER STORM WARNING FROM 10 PM THIS EVENING TO 5 AM PST SUNDAY  
FOR NORTHERN PANHANDLE.  
 
WA...WINTER STORM WARNING FROM 10 PM THIS EVENING TO 5 AM PST SUNDAY  
FOR NORTHEAST MOUNTAINS-OKANOGAN HIGHLANDS.  
 
WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 PM PST  
SATURDAY FOR OKANOGAN VALLEY-WATERVILLE PLATEAU-WENATCHEE  
AREA.  
 
WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 4 PM PST  
SATURDAY FOR CENTRAL CHELAN COUNTY-WESTERN CHELAN COUNTY-  
WESTERN OKANOGAN COUNTY.  
 

 
 

 
 
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