[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Western Washington


821 
FXUS66 KSEW 011640
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
840 AM PST SUN FEB 1 2015

.SYNOPSIS...A WEAK COLD FRONT WILL MOVE THROUGH TODAY FOR RAIN AT 
TIMES. A BRIEF AND WEAK RIDGE WILL GIVE A DECREASING CHANCE OF 
SHOWERS TONIGHT. ANOTHER FRONTAL SYSTEM WILL MOVE THROUGH THE AREA 
ON MONDAY...WITH MORE LIGHT RAIN LIKELY. SOME LIGHT SHOWERS WILL 
LINGER TUESDAY INTO WEDNESDAY AS WEAK DISTURBANCES MOVE THROUGH THE 
AREA. A TRANSITION TO A FAIRLY WET AND MILD PATTERN WILL BEGIN 
THURSDAY AND CONTINUE THROUGH NEXT WEEKEND. 

&&

.SHORT TERM...SATELLITE IMAGERY AND RADARS SHOW A WEAK FRONT OVER 
THE OUTER COASTAL WATERS THIS MORNING MOVING SLOWLY EAST. THE FRONT 
WILL SLOW AND WEAKEN AS IT MOVES ONSHORE THIS AFTERNOON. TODAY WILL 
BE A CLOUDY DAY WITH OCCASIONAL LIGHT RAIN AND TEMPERATURES IN THE 
MID 40S TO NEAR 50 DEGREES. 

THE AIR MASS BEHIND THIS FRONT IS NOT PARTICULARLY COOL OR UNSTABLE 
ALOFT...SO EXPECT SHOWER ACTIVITY TO DIMINISH BEHIND THE FRONT THIS 
EVENING. THE LATE EVENING THROUGH PRE DAWN HOURS MAY BE DRY ACROSS 
THE AREA...JUST CLOUDY...BETWEEN THE FIRST FRONT AND THE NEXT 
INCOMING SYSTEM THAT IS NOW ALONG ABOUT 142W. WITH ALL THE CLOUD 
COVER AROUND...TEMPERATURES WILL HOLD MAINLY IN THE LOWER 40S 
TONIGHT.

ANOTHER WEAK FRONT WILL MOVE ACROSS THE AREA ON MONDAY. THE 12Z NAM 
AND 12Z GFS SOLUTIONS BOTH SHOW THE RAIN MOVING INTO THE AREA FROM 
THE SOUTHWEST DURING THE MORNING HOURS ON THE COAST AND THE SOUTHERN 
HALF OF THE INTERIOR THEN THROUGH THE AREA DURING THE AFTERNOON 
HOURS. THIS FRONTAL FEATURE WILL BE LOSING ITS IDENTITY AS IT MOVES 
ACROSS THE AREA LATER IN THE DAY. 

TUESDAY AND TUESDAY NIGHT WILL LIKELY SEE SHOWERS AT TIMES. A WARM 
FRONT IN THE SOUTHERN STREAM WILL AFFECT EXTREME NORTHERN CALIFORNIA 
INTO CENTRAL OREGON GIVING STEADIER RAIN DOWN THERE. BUT THE 
REMNANTS OF A WRAP AROUND FEATURE THAT IS SEEN MOVING AROUND THE 
DEEP AND MATURE LOW NOW CENTERED NEAR 46N 158W WILL SPLIT OFF AND 
MOVE ACROSS ESPECIALLY THE NORTHERN HALF OF WESTERN WASHINGTON 
ENHANCING SHOWER ACTIVITY AND POSSIBLY CONVERGENCE ZONE ACTIVITY 
INITIATED BY WNW FLOW ALOFT. 

SHOWER ACTIVITY WILL LIKELY COME TO AN END EARLY WEDNESDAY...BUT THE 
INCOMING GFS DOES SHOW WARM ADVECTION PRECIPITATION MOVING INTO THE 
SOUTHERN PORTIONS OF WESTERN WASHINGTON LATE WED AFTERNOON OR 
EVENING. 

CURRENT FORECASTS APPEAR TO BE GENERALLY ON TRACK. NO MORNING UPDATE 
IS PLANNED. ALBRECHT

.LONG TERM...FROM THE PREVIOUS LONG TERM SOLUTION...MODEL SOLUTIONS 
FOR WEDNESDAY CONTINUE TO SHOW A LACK OF CONSISTENCY AMONG THE 
MODELS. THE ECMWF HAS A WARM FRONT OVER OREGON TRYING TO LIFT NORTH 
INTO WESTERN WASHINGTON. THE GFS HAS A WEAK SHORTWAVE RIDING BY TO 
THE NORTH OF THE AREA. GFS ENSEMBLES SHOW LITTLE VARIATION IN THEIR 
SOLUTION ON WEDNESDAY WHICH LENDS SOME CONFIDENCE TO THE GFS 
SOLUTION BUT WITH THE LACK OF MODEL CONSENSUS WILL KEEP THE CHANCE 
POPS IN THE FORECAST. WHILE THERE ARE SOME DIFFERENCES IN THE TIMING 
OF THE SYSTEMS BEGINNING THURSDAY THE EXTENDED MODELS ARE IN MUCH 
BETTER AGREEMENT IN REGARD TO THE OVERALL PATTERN TURNING WARMER AND 
WETTER BEGINNING THURSDAY AND CONTINUING THROUGH NEXT WEEKEND. 
TIMING OF THE INDIVIDUAL FEATURES IS TOUGH AT THIS POINT SO A BROAD 
BRUSH RAIN LIKELY/RAIN AT TIMES FORECAST LOOKS GOD THURSDAY THROUGH 
SATURDAY. FELTON
 
&&

.HYDROLOGY...FLOODING IS NOT EXPECTED THROUGH AT LEAST THURSDAY. 

A SERIES OF SYSTEMS MOVING THROUGH THE AREA THURSDAY NIGHT THROUGH 
SATURDAY WILL CAUSE RIVERS TO RISE BUT WITH A FEW BREAKS IN THE 
STEADY PRECIPITATION THE ONLY THREAT OF FLOODING IN THIS SCENARIO 
LOOKS TO BE ON THE SKOKOMISH RIVER NEXT WEEKEND. FELTON/ALBRECHT
 
&&

.AVIATION...MOIST WESTERLY FLOW ALOFT PREVAILS OVER WESTERN 
WASHINGTON THIS MORNING...AS A WEAK FRONT MOVES INLAND FROM THE 
OFFSHORE WATERS. THE FRONT WILL MOVE EAST OF THE CASCADES THIS 
EVENING...BUT THE AIR MASS WILL REMAIN MOIST AT LOWER LEVELS. A FLAT 
UPPER RIDGE WILL REMAIN OVER THE PACIFIC NORTHWEST. 

CEILINGS ACROSS THE FORECAST AREA ARE MAINLY 6000 FT OR ABOVE AT 
PRESENT...BUT THERE IS SPOTTY LIGHT RAIN AND AREAS OF VISIBILITY 
3-5SM -RA BR. CONDITIONS WILL DETERIORATE DURING THE NEXT FEW HOURS 
AS PRECIPITATION INCREASES...AND WIDESPREAD 3-5SM -RA BR AND CEILING 
BKN-OVC025 IS LIKELY LATE THIS MORNING AND AFTERNOON. RAIN WILL 
MOSTLY END OVER THE LOWLANDS THIS EVENING...BUT CEILINGS WILL 
PROBABLY REMAIN LOW THROUGH TONIGHT AND MONDAY MORNING WITH 
WIDESPREAD STRATUS.

KSEA...SOUTHERLY WIND 6-10 KT. CEILING WILL FALL OVER THE NEXT FEW 
HOURS AS RAIN INCREASES...AND VISIBILITY 3-5SM -RA BR SEEMS LIKELY 
AT TIMES. RAIN WILL END LATE TODAY OR THIS EVENING...BUT STRATUS 
WILL PROBABLY CONTINUE TONIGHT AND MONDAY MORNING.   MCDONNAL

&&

.MARINE...A WEAK FRONT WILL MOVE THROUGH THE COASTAL WATERS OF 
WESTERN WASHINGTON THIS MORNING AND THEN INLAND THIS AFTERNOON. THIS 
FEATURE IS PRODUCING SMALL CRAFT ADVISORY SOUTHERLIES OVER THE 
COASTAL WATERS FROM AROUND DESTRUCTION ISLAND NORTHWARD...AND THESE 
SHOULD CONTINUE INTO THE AFTERNOON. THE FRONT WILL PROBABLY ALSO 
PRODUCE MARGINAL SMALL CRAFT ADVISORY WINDS OVER THE EAST ENTRANCE 
STRAIT OF JUAN DE FUCA...ADMIRALTY INLET...AND NORTHERN INLAND 
WATERS THIS AFTERNOON. 

A NEGATIVELY TILTED FRONT WILL MOVE THROUGH THE FORECAST AREA MONDAY 
AFTERNOON AND EVENING. THIS WILL ALSO BE A RELATIVELY WEAK 
FEATURE...BUT IT SHOULD RESULT IN SMALL CRAFT ADVISORY WINDS OVER 
MOST OF THE MARINE ZONES. WEAK HIGH PRESSURE WILL BE OVER THE REGION 
TUESDAY AND WEDNESDAY...AND A STRONGER FRONTAL SYSTEM WILL ARRIVE 
THURSDAY.   MCDONNAL

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY COASTAL WATERS ZONES 150 153 170 173.
     SMALL CRAFT ADVISORY THIS AFTERNOON EAST ENTRANCE STRAIT OF 
       JUAN DE FUCA...ADMIRALTY INLET...NORTHERN INLAND WATERS.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT 
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML









[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Southwestern Washington and Western Oregon


769 
FXUS66 KPQR 011640
AFDPQR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR 
838 AM PST SUN FEB  1 2015

.SYNOPSIS...A WEAK COLD FRONT WILL BRING RAIN ACROSS THE REGION
THROUGH THIS AFTERNOON. SHOWERS WILL LINGER OVER THE CASCADES THIS
EVENING AS SNOW LEVELS LOWER TO CLOSE TO THE CASCADE PASSES. A MUCH
WETTER SYSTEM IMPACTS THE AREA LATE SUNDAY NIGHT AND MONDAY. COMPUTER
MODEL SOLUTIONS SHOW HIGH VARIABILITY TUESDAY THROUGH THURSDAY...BUT
THE MOST LIKELY SCENARIO IS A BRIEF DRYING TREND WEDNESDAY AND
WEDNESDAY NIGHT...FOLLOWED BY A RETURN TO A MUCH WETTER PATTERN LATE
IN THE WEEK. 
&&

.UPDATE...A COLD FRONT IS PRODUCING RAIN OVER NW OREGON AND SW
WASHINGTON THIS MORNING. THE FRONT IS MOVING QUITE FAST BUT SATELLITE
IMAGERY SHOWS A WAVE DEVELOPING ON THE BACK SIDE OF IT...THAT SHOULD
SUSTAIN RAIN INTO THE AFTERNOON. 

THE SNOW LEVELS ARE GENERALLY HIGH...BUT COLD AIR HAS BEEN SLOW TO
SCOUR OUT AT A FEW LOCATIONS. MANY AREAS OF THE UPPER HOOD RIVER ARE
STILL REPORTING BELOW FREEZING TEMPERATURES AS WELL AS SOME VALLEY
LOCATIONS OF THE SW WASHINGTON CASCADES LIKE BUCK CREEK AND DRY
CREEK. IT IS POSSIBLE THAT THESE AREAS ARE EXPERIENCING FREEZING
RAIN...BUT HAVE NOT HAD ANY REPORTS TO CONFIRM OR DENY IT. HAVE ADDED
A CHANCE FOR FREEZING RAIN FOR THE UPPER HOOD RIVER VALLEY FOR THIS
MORNING AND A SLIGHT CHANCE OF FREEZING RAIN FOR THIS AFTERNOON. 

SHOWERS WILL TAPER OFF THIS EVENING WITH SHOWERS MOSTLY REMAINING
OVER THE CASCADES. SNOW LEVELS WILL LOWER AT THIS TIME DOWN TO AROUND
4500 FEET FOR THE SW WASHINGTON AND NORTHERN OREGON CASCADES AND TO
5500 FEET FOR THE CENTRAL OREGON CASCADES...WITH VERY LIGHT SNOW
ACCUMULATIONS POSSIBLE..MAINLY ABOVE 5000 FEET. TJ

FROM PREVIOUS SHORT-TERM DISCUSSION...MODELS IN GENERAL AGREEMENT
REGARDING THE SUN NIGHT/MON SYSTEM. MAIN MODEL DISCREPANCIES LIE IN
THE TIMING AND FOCUS OF THE HEAVIEST QPF. THE ECMWF SEEMS TO BE A BIT
FASTER AND KEEPS THE HEAVIEST QPF OVER SWRN OREGON MON MORNING. GFS
HAS THE QPF BULLS-EYE A LITTLE FURTHER NORTH WHILE THE NAM IS JUST A
TOUCH MORE N THAN THE GFS. NAM ALSO ALSO DEVELOPS A SLIGHTLY STRONGER
SURFACE LOW NEAR BUOY 029 18Z MON WHILE THE GFS HAS IT A BIT WEAKER
AND FURTHER N. BREEZY TO WINDY SOUTH WIND WOULD DEVELOP IF THE NAM
VERIFIES...ESPECIALLY ALONG THE COAST. NAM ALSO SHOWS A SHARPER AND
MORE DYNAMIC COLD FRONT. THIS WOULD ALSO BREAK THROUGH VALLEY
INVERSIONS AND WARM UP THE LOWLANDS CONSIDERABLY...JUST BEFORE COLD
FRONTAL PASSAGE. IN ADDITION...00Z NAM BUFR SOUNDINGS SHOW THE
POTENTIAL FOR SOME INSTABILITY...WITH CAPE OF 400-800 J/KG JUST ABOVE
LOW-LEVEL INVERSION. THERE IS THE SLIM POTENTIAL MONDAY AFTERNOON FOR
SOME SURFACE-BASED CONVECTION WITH THE COLD FRONT. THE SOUNDINGS ALSO
SHOW DECENT DIRECTIONAL SHEAR WITHIN THE UNSTABLE LAYER. HAVE
MAINTAINED THE SLIGHT CHANCE OF THUNDER MONDAY AFTERNOON AND EARLY
EVENING.      

TOTAL QPF FOR THIS SYSTEM EXPECTED TO BE ON THE ORDER OF 1 TO 1.5
INCHES FOR THE MOUNTAINS AND 0.25 TO 0.75 FOR THE LOWLANDS. MODELS
THEN START TO DIVERGE MON NIGHT AND BEYOND. THE ECMWF BRINGS A WARM
FRONT INTO SWRN OREGON TUE MORNING....AS DOES THE NAM BUT IT HAS IT A
LITTLE MORE TO THE S...CLOSER TO THE CALIFORNIA BORDER. THE GFS IS
MORE IN BETWEEN THE TWO. THIS WARM FRONTAL FEATURE GRADUALLY DRIFTS N
TUE AFTERNOON...BUT STAYS S OF THE COLUMBIA RIVER BY 00Z WED.
THUS...SNOW LEVELS WILL BE MUCH LOWER IN THE S WA AND FAR N OREGON
CASCADES TUE...COMPARED TO AREAS S OF MT. JEFFERSON. WEISHAAR  

LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...MODELS SOLUTIONS VARY IN
THE MID-WEEK PERIOD. THE GFS INDICATES AN UPPER RIDGE RETURNING TO
THE PACIFIC NW WED WHILE THE ECMWF KEEPS A REMNANT WARM-FRONTAL
BAROCLINIC BOUNDARY OVER THE REGION. THERE IS A THE GEM IS MORE IN
LINE WITH THE GFS COMPARED TO THE ECMWF. MADE SOME SMALL ADJUSTMENTS
TO THE WED AND WED NIGHT PERIODS...MAINLY TO TRIM POPS A BIT. SHOULD
THE GFS PAN OUT...FURTHER REDUCTION WOULD BE NECESSARY AND WOULD ALSO
NEED TO CONSIDER THE INCLUSION OF NIGHT NIGHT AND MORNING FOG FOR THE
INTERIOR VALLEYS. MODELS ARE IN SURPRISING AGREEMENT FOR THE END OF
THE EXTENDED PERIOD. IT LOOKS LIKE A PERIOD OF MUCH WETTER WEATHER
WILL IMPACT THE REGION LATE IN THE WEEK...AND POSSIBLY INTO NEXT
WEEKEND AS A SWATH OF SUBTROPICAL MOISTURE COMBINED WITH A SERIES OF
ATMOSPHERIC WAVES SETS UP OVER THE NE PACIFIC. THIS WEATHER PATTERN
WILL LIKELY BRING A SUBSTANTIAL AMOUNT OF RAIN TO PARTS OF THE
PACIFIC NORTHWEST. HOWEVER...CONFIDENCE IN TIMING AND AREAS OF
PRIMARY QPF FOCUS REMAIN RATHER LOW AT THIS TIME. WEISHAAR
&&

.AVIATION...PREDOMINANTLY VFR CONDITIONS IN LIGHT RAIN WITH AN
APPROACHING COLD FRONT. OCCASIONAL MVFR CIGS AND VIS ARE POSSIBLE
AS THE COLD FRONT PUSHES ONSHORE AFTER 18Z TODAY. LIFR CIGS AT
KEUG PERSIST...BUT SHOULD IMPROVE TO MVFR AT LEAST BEHIND THE
FRONT THIS AFTERNOON/EVENING. GUSTY EAST WINDS WILL CONTINUE TO
IMPACT LOCATIONS CLOSEST TO THE GORGE THROUGH THIS AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS IN LIGHT RAIN WILL PREVAIL
TODAY WITH GUSTY EAST WINDS. EXPECT FRONTAL PASSAGE AND A
TRANSITION TO SHOWERS NEAR 23Z. /27
&&

.MARINE...GUSTY SOUTH WINDS HAVE INCREASED A BIT MORE THAN MODEL
GUIDANCE WAS ORIGINALLY INDICATING WITH AN APPROACHING COLD
FRONT...SO HAVE ISSUED A SMALL CRAFT ADVISORY FOR WIND GUSTS UP TO
25 KT THROUGH LATE THIS MORNING/EARLY AFTERNOON. SEAS START TO
INCREASE WITH THIS SYSTEM BUT LOOK TO REMAIN BELOW 10 FT TODAY. 

A SECOND...STRONGER SYSTEM MOVES THROUGH ON MONDAY...BRINGING A
VERY GOOD CHANCE FOR SMALL CRAFT WINDS WITH GUSTS TO 30 KTS
LIKELY. THIS SYSTEM WILL ALSO INCREASE SEAS TO 10 TO 12 FT. WINDS
AND SEAS START TO SUBSIDE LATE MONDAY...BRINGING SEAS BACK DOWN TO
AROUND 7 TO 8 FT BY MIDWEEK AS SHORT-LIVED HIGH PRESSURE BUILDS
BACK OVER THE REGION. MODELS ARE IN AGREEMENT THAT AN EVEN
STRONGER SYSTEM WILL MOVE THROUGH LATE THIS WEEK...WHICH COULD
GENERATE SOUTHERLY GALES AND BRING SEAS UP TO NEAR 20 FT THURSDAY
OR FRIDAY. THERE IS UNCERTAINTY IN THE TIMING AND TRACK OF THIS
SYSTEM...WHICH SHOULD GET IRONED OUT AS THE WEEK PROGRESSES.
-MCCOY/27
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST THIS AFTERNOON    
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR   
     OUT 60 NM. 
&&

$$

INTERACT WITH US VIA SOCIAL MEDIA     
WWW.FACEBOOK.COM/NWSPORTLAND	
WWW.TWITTER.COM/NWSPORTLAND
 
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON 
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS 
COMMONLY REFERRED TO AS THE FORECAST AREA.

[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Southeastern Washington and Northeastern Oregon


283 
FXUS66 KPDT 011758 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
957 AM PST SUN FEB 1 2015

UPDATED AVIATION DISCUSSION

.UPDATE...AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
TODAY AND TONIGHT BRINGING A RELATIVELY HIGH POP BUT LOW QPF EVENT
TO OUR FORECAST AREA. RAIN IS ALREADY SPREADING EAST OF THE
CASCADES AS ANTICIPATED. FOG IS BEGINNING TO LIFT IN CENTRAL
OREGON SO PLAN ON EITHER CANCELING OR LETTING THE FREEZING FOG
ADVISORY EXPIRE THIS MORNING. MADE SOME MINOR TWEAKS TO THE MAX
TEMPERATURES TODAY...OTHERWISE THE FORECAST FOR TODAY IS IN GOOD
SHAPE.

&&

.AVIATION...18Z TAFS... LINGERING IFR/LIFR CIGS AT KBDN...KRDM AND 
KPDT SHOULD LIFT TO MVFR BY 19-20Z TODAY AS A SYSTEM MOVES IN MIXING 
OUT THE STUBBORN LOW CLOUDS. EXPECTING MAINLY MVFR CIGS/VIS ALONG 
WITH LIGHT RAIN FOR ALL TAFS SITES THIS AFTERNOON THROUGH ABOUT 06Z 
THIS EVENING BEFORE THE RAIN SHOWERS TAPER OFF AND CIGS LIKELY 
SCATTER OUT. WATCHING FOR SOME SCT LOW CLOUDS AND MVFR BR AFTER 
02/10-12Z AT SEVERAL TAF SITES. THE NEXT WEATHER SYSTEM WILL BEGIN 
AFFECTING KBDN AND KRDM AFTER 02/15Z BRING STEADY LIGHT RAIN WITH 
BORDERLINE IFR CIGS ONCE AGAIN. 77

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  41  36  49  38 /  50  40  60  30 
ALW  42  39  49  40 /  50  40  60  30 
PSC  43  34  48  38 /  40  30  60  20 
YKM  41  32  45  33 /  30  20  60  20 
HRI  43  36  49  40 /  40  30  60  20 
ELN  40  31  43  33 /  40  20  60  20 
RDM  48  36  53  35 /  40  30  70  20 
LGD  42  34  46  35 /  40  50  70  40 
GCD  43  33  49  33 /  40  40  60  30 
DLS  44  38  49  40 /  50  30  70  20 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FREEZING FOG ADVISORY UNTIL 10 AM PST THIS MORNING ORZ511.

WA...NONE.
&&

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

$$

78/77






[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Northeastern Washington and Northern Idaho


664 
FXUS66 KOTX 011221
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
420 AM PST SUN FEB 1 2015

.SYNOPSIS...
A frontal system will bring light snow to much of the region on
Today. Another front is expected on Monday, and it should bring
rain and mountain snow. More mild and wet weather disturbances
are expected Thursday into the weekend.

&&

.DISCUSSION...

...Light Snow Today for Northern Washington and Idaho Panhandle...

Today and Tonight: The first in a series of moist frontal systems
will move through the Pacific Northwest today. This initial shot
of moisture today should produce light snow accumulations from the
East Slopes of the Cascades across the northern tier of counties
in northern Washington into the Idaho Panhandle. Winter Weather
Advisories have been posted from the Okanogan Highlands through
northeast Washington into the Idaho Panhandle.

* Snow Levels: Some of the tricky forecast areas for today will be
  over the Palouse, Spokane area, and southern Idaho Panhandle.
  The warm front driving today's precipitation does not appear to
  produce much wind near the surface. Without efficient boundary
  layer mixing, it will be a tough call whether temperatures in
  these aforementioned areas will be cold enough to produce
  accumulating snow. These areas will see precipitation primarily
  during the afternoon and evening. This "warm" time of day may
  inhibit accumulations during the afternoon, but as the sun sets
  pavement temperatures may cool enough that heavier snow bands
  may produce slick driving conditions.

* Snow Amounts: 1 to 3 inch accumulations look to be a good bet
  from the Methow Valley to northeast Washington into the Idaho
  Panhandle. There is good agreement between the NAM, GFS and
  ECMWF that deep layer westerly flow will produce the typical
  precipitation shadow for Wenatchee and Moses Lake areas. The
  westerlies should provide enough orographic enhancement that the
  mountains of the Idaho Panhandle above 3000 feet should receive
  3 to 6 inches of accumulation by Monday morning.

* Timing: Meteorologically today's snow looks to be pretty typical
  for this region. We see several 1 to 3 inch events most years.
  However, the timing of the snow for places like Spokane, Couer
  D'Alene, Sandpoint, and Kellogg may be problematic. The
  afternoon and evening timing of today's event will be coincident
  with a significant sporting event of particular regional
  interest. The festivities associated with said sporting event
  combined with potential for winter driving conditions will have
  the potential to produce more accidents than we would normally
  experience on a typical Sunday afternoon/evening.

Monday: Precipitation chances and amounts for Monday have been
lowered a bit, and may need to be lowered further. There is
reasonable model agreement that the bulk of precipitation on
Monday will not arrive until afternoon and evening. Snow levels
will be on the rise Monday. At this time, it looks like a mainly
rain event for the valleys with snow for the mountains above
3000-4000 feet. /GKoch

Monday night through Thursday night...The warm southwest to
northeast trajectory of approach for storm systems continues with
Monday evening remaining quite wet with fairly high snow levels.
There is a subtle change with the exit of the storm as it moves
into Northwest Montana Tuesday as it appears a very weak cold
front may drop down from the north and allow cooling and lowering
of snow levels Tuesday. This complicates the storm track and is
different than what models had depicted earlier. Now models hint
at this cold front passage from the north pushes the storm track
associated with the ridge in the area further south with more
influence on Oregon now and less on Northern Washington for late
Tuesday, regardless by Tuesday night what appears to be a
deformation zone of sorts in the vicinity of where the old cold
front stalled remains an area of focus for precipitation as
moisture streams in from the west/southwest through it. With this
in mind high pops remain Wednesday as it remains in the area and
behaves as a warm front at times as it gets pushed north Wednesday
afternoon through Wednesday night. Thursday through Thursday night
remains cluttered with similar high pops with yet another
baroclinic band spiraling outward from large low pressure area in
Gulf of Alaska that taps into subtropical moisture sweeps through
Washington and North Idaho allowing for continued rather high snow
levels and forecast temperatures to remain on the warm side of
climo. /Pelatti

Friday through Saturday Night: Mild and active pattern leads into
the weekend as moist subtropical air comes into the region. Models
are now in decent agreement showing a very moisture rich plume
pushing into the region Friday with deep subtropical origins. An
atmospheric river set-up looks promising which highly supports the
notion of widespread precipitation Friday into Friday Night. With
precipitable water values surpassing an inch for some,
precipitation amounts could end up being rather impressive for the
24 hr period. The highest amounts will fall in the Cascades which
could see upwards of 2 inches with up to 1.5 inches in the ID
Panhandle. Snow levels surge to at least 6k feet by midday Friday
supporting widespread rain with only the highest mountains seeing
snow. Overall this is not great news in terms of trying to build a
snowpack, which we have struggled with all winter. The one watch
spot for impacts would be in the far northern valleys of the
Cascades and along the international border which may hold onto
enough cold air Friday morning to support a period of freezing
rain before an eventual switch to rain by midday. Confidence in
this is not high at this point and will greatly depend on how much
they cool Thursday night. Increased confidence will likely come as
we further approach the event.

Precipitation chances diminish moving into Saturday as the rich
moisture feed is no longer directed into the region. With a strong
westerly component in the winds, the locations to dry out first
would be in the east slopes and lower Basin due to increased
shadowing off the Cascades before eventually spreading further
east. Better mixing behind the main moisture band will allow mid
and upper level winds to more efficiently mix to the surface in
turn bringing gusty winds. This will be most notable in the higher
elevation locations (especially in the Blue Mtns and Camas
Prairie), but even the valleys will note an uptick in winds.
Temperatures will be the other thing on the rise as mild southerly
winds bring in warmer air. This will send daytime highs into the
40s and 50s with overnight lows struggling to fall below freezing
for most. Overall a wet and mild pattern for the end of the week.
/Fliehman

&&

.AVIATION...
12Z TAFS: Light snow will spread into eastern Washington and north
Idaho by mid to late morning. Look for runway accumulations of 1
to 2 inches in places like Spokane, Coeur D'Alene, Sandpoint,
Colville, and Kellogg. Further south, Pullman will be a tough call
with a potential change from snow to rain in the afternoon. Low
stratus and fog will be a good possibility tonight as the
precipitation moves out of the region. Not much post frontal
mixing is anticipated after the snow/rain ends. Weak upslope flow
into Spokane and Coeur D'Alene will likely lead to ceilings at or
below 1000 feet. /GKoch



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        33  30  38  32  39  29 / 100  30  60  50  20  20 
Coeur d'Alene  33  30  39  34  40  29 / 100  70  60  70  30  20 
Pullman        35  32  43  37  45  34 /  90  70  60  60  30  30 
Lewiston       40  36  47  39  49  36 /  50  80  50  50  30  30 
Colville       33  30  37  31  36  26 / 100  30  50  40  20  10 
Sandpoint      33  30  37  32  37  27 /  90  60  50  70  30  20 
Kellogg        33  32  39  34  39  29 / 100 100  50  90  60  30 
Moses Lake     38  28  41  33  44  31 /  30  10  50  20  30  20 
Wenatchee      39  31  37  33  42  32 /  50  10  50  20  30  30 
Omak           35  28  35  31  36  28 /  70  10  50  30  20  20 

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 10 AM this morning to Midnight PST 
     tonight for Central Panhandle Mountains-Coeur d'Alene Area-
     Idaho Palouse-Northern Panhandle.

WA...Winter Weather Advisory from 7 AM this morning to 7 PM PST this 
     evening for Northeast Mountains-Okanogan Highlands-Spokane 
     Area.

&&

$$


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