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

Western Washington


910 
FXUS66 KSEW 120456
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
856 PM PST THU FEB 11 2016

.SYNOPSIS...A WARM FRONT WILL BRING LIGHT RAIN TO WESTERN WASHINGTON
TONIGHT...FOLLOWED BY A WEAK COLD FRONT FRIDAY MORNING. AN UPPER
LEVEL TROUGH WILL PRODUCE SHOWERS FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. A PAIR OF WARM FRONTS WILL BRING RAIN SATURDAY AFTERNOON
THROUGH SUNDAY EVENING. WEST FLOW ALOFT WILL MAINTAIN AN ACTIVE
WEATHER PATTERN INTO EARLY NEXT WEEK.  

&&

.SHORT TERM...MODERATE SW FLOW ALOFT OVER THE REGION IS PUSHING A
WARM FRONT NE ACROSS W WA THIS EVENING. IR IMAGERY SHOWS THE BACK
EDGE OF THE WARM FRONT OFFSHORE ALONG ROUGHLY 128W. RADAR SHOWS
LIGHT RAIN ACROSS ALL OF W WA...BUT RATHER THAN CONTINUOUS
WIDESPREAD RAIN...IT IS MORE BROKEN UP WITH SMALL HOLES SUGGESTING
THE RAIN WILL BE MORE INTERMITTENT. THE 00Z GFS TAKES THE BACK EDGE
OF THE WARM FRONT NE ACROSS ACROSS W WA AFTER MIDNIGHT...BETWEEN 09Z-
12Z. 

THE COLD FRONT...OR WHAT THE MODELS DEVELOP IN TO A COLD FRONT...IS
CURRENTLY A WEAK LITTLE FEATURE OFFSHORE ALONG 130W AT 03Z/7 PM.
MODELS BRING A 300 MB JET STREAK ENE OVER OREGON ON FRIDAY AROUND
12Z WITH THE LEFT EXIT REGION MOVING OVER THE TOP OF THE SLOWLY
ADVANCING WEAK FRONT. THE GFS IN PARTICULAR STRENGTHENS THE FRONT AS
IT MOVES OVER THE COAST AND THEN INLAND 12Z-18Z. THE GFS THEN BREAKS
THE FRONT UP AS IT MOVES OVER THE CASCADES 21Z-00Z. QPF SHOULD BE
AROUND A QUARTER INCH OVER THE LOWLANDS...GIVE OR TAKE A TENTH...AND
COULD BE UP AROUND A HALF INCH ALONG THE COAST. SNOW LEVELS WILL BE
ABOVE 6000 FEET TONIGHT THROUGH FRIDAY MORNING WITH JUST RAIN IN THE
CASCADE PASSES.

AFTER THE COLD FRONT DEPARTS FRIDAY AFTERNOON THE MODELS HAVE
REMAINED CONSISTENT IN BRINGING THE UPSTREAM UPPER LEVEL
TROUGH...CURRENTLY OFFSHORE BETWEEN 135W-145W...INLAND FRIDAY NIGHT.
THE GFS HAS SPED UP TO THE ECMWF SOLUTION AND NOW HAS THE TROUGH
AXIS OVER THE CASCADES BY 09Z. ALTHOUGH THE AIR MASS BECOMES MORE
UNSTABLE...LIFTED INDICES ARE NOT LOW ENOUGH TO CONSIDER
THUNDERSTORMS. SNOW LEVELS LOWER WITH THE COOLER AIR IN THE
TROUGH...BUT ONLY DROP DOWN TO ABOUT 3500 FEET LATE FRIDAY NIGHT AND
SATURDAY MORNING. THIS COULD RESULT IN SEVERAL INCHES OF SNOW AT THE
PASSES.

THE MODELS DEVELOP A BROAD FLAT UPPER LEVEL RIDGE
OFFSHORE...UPSTREAM OF FRIDAY NIGHTS UPPER LEVEL TROUGH. STRONG W
FLOW ALOFT THROUGH THE RIDGE WILL BRING A LARGE AREA OF WARM
ADVECTION OVER W WA SATURDAY AFTERNOON AND NIGHT. THE INITIAL RAIN
SHOULD BE RATHER LIGHT...BUT SHOULD INCREASE SATURDAY EVENING AS THE
WARM FRONT NEARS THE COAST. GFS 925 MB TEMPERATURE GRADIENTS SUGGEST
A WARM FRONT PASSAGE ALONG THE COAST AROUND 06Z. 

RIGHT BEHIND THE WARM FRONT IS ANOTHER LARGE AREA OF WARM ADVECTION
THAT SHOULD KEEP IT RAINY THROUGH SUNDAY. KAM

.LONG TERM...PREVIOUS DISCUSSION FROM THE 245 PM AFD...ALL MODELS
MOVE THE CONVEYOR BELT OF MOISTURE NORTH ON SUNDAY NIGHT AND MONDAY
THOUGH THEY DIFFER IN THE DETAILS SUCH AS HOW FAST AND HOW FAR
NORTH. THERE IS SOME CHANCE THAT HEAVY RAIN COULD CONTINUE OVER THE
OLYMPICS AND NORTH CASCADES FOR AWHILE.
RECENT MODEL TRENDS HAVE BEEN TOWARD LESS WET SOLUTIONS FOR
WASHINGTON WITH MOST OF THE PRECIPITATION IN CANADA. ON TUESDAY
MODELS BRING THE NOW LESS ENERGETIC FRONT BACK SOUTH THROUGH
WASHINGTON. THE GFS IS SLOWER AND WETTER WITH THIS TRANSITION. FOR
NOW HAVE MOSTLY CHANCE POPS FOR MONDAY AND TUESDAY EXCEPT FOR THE
EXTREME NORTH.

THE GFS AND EURO ARE TRULY AT ODDS WEDNESDAY AND THURSDAY. THEY
DIFFER IN THE BROAD PATTERN AS WELL AS THE DETAILS. HAVE KEPT BROAD
BRUSH CHANCE POPS IN THE FORECAST. BURKE

&&

.HYDROLOGY...RIVER FLOODING IS UNLIKELY THROUGH SATURDAY. THERE IS
SOME POTENTIAL FOR HEAVY RAIN OVER THE OLYMPICS AND NORTH CASCADES
BEGINNING SATURDAY NIGHT WHICH COULD CAUSE THE SKOKOMISH RIVER AND
POSSIBLY A FEW RIVERS IN THE NORTH CASCADES TO FLOOD EARLY NEXT WEEK.

&&

.AVIATION...MOIST SOUTHWESTERLY FLOW ALOFT CONTINUING INTO FRIDAY.
AIR MASS STABLE BECOMING SLIGHTLY UNSTABLE BEHIND COLD FRONT FRIDAY
MORNING INTO FRIDAY AFTERNOON. 

WARM FRONT WILL MOVE THROUGH WESTERN WASHINGTON OVERNIGHT WITH THE TRAILING
COLD FRONT MOVING THROUGH FRIDAY MORNING. WIDE VARIETY OF CEILINGS
AHEAD OF THE COLD FRONT WITH A POCKET OF IFR BETWEEN SHELTON AND OLYMPIA AND
MORE IFR CEILINGS ALONG THE STRAIT OF JUAN DE FUCA WITH THE LOW LEVEL
NORTHEASTERLY WINDS CREATING SOME UPSLOPE CONDITIONS AT PORT ANGELES. MOST
OF THE REMAINDER OF THE AREA CEILINGS IN THE LOW END OF VFR...3500-4500
FEET. CEILINGS LOWERING BRIEFLY WITH THE WARM FRONT PASSAGE OVERNIGHT. 
MOSTLY MVFR CEILINGS EXPECT WITH THE COLD FRONT FRIDAY MORNING. ONSHORE
FLOW BEHIND THE COLD FRONT FRIDAY AFTERNOON WITH CEILINGS LIFTING BACK UP INTO
THE 3500-5000 FOOT RANGE. 

KSEA...CEILINGS NEAR 3500 FEET INTO EARLY FRIDAY MORNING. CEILINGS LOWERING
AFTER 12Z DOWN TO NEAR 2000 FEET RIGHT WITH THE COLD FRONT. IMPROVEMENT TO VFR
CAN BE EXPECTED AFTER 18Z FRI BEHIND A COLD FRONT. SOUTHEAST WIND 6 TO 10 KNOTS
BECOMING SOUTHERLY 8 TO 12 KNOTS 15Z-18Z FRIDAY. FELTON 

&&

.MARINE...WARM FRONT MOVING THROUGH THE WATERS OVERNIGHT WITH THE TRAILING 
COLD FRONT MOVING THROUGH FRIDAY MORNING. SMALL CRAFT ADVISORIES REMAIN IN
EFFECT FOR THE COAST...ENTRANCES TO THE STRAIT AND NORTHERN INLAND WATERS. 
SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP IN ADMIRALTY INLET LATER THIS
EVENING. 

POST FRONTAL ONSHORE FLOW WILL FOLLOW FRIDAY AFTERNOON INTO SAT MORNING. SMALL
CRAFT ADVISORY SOUTH FLOW IS LIKELY OVER PUGET SOUND AND HOOD CANAL
FRIDAY NIGHT AND SATURDAY MORNING AS FLOW ALOFT INTERACTS WITH THE
OLYMPICS AND A MESO LOW FORMS OVER THE NE OLYMPIC PENINSULA.

A SERIES OF FRONTAL SYSTEMS WILL GIVE SMALL CRAFT ADVISORY
CONDITIONS TO MOST OF THE WATERS SAT NIGHT THROUGH EARLY NEXT WEEK.
FELTON/ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PST FRIDAY FOR COASTAL WATERS 
     FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL 
     WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL 
     WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-
     COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10 
     NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 
     10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE 
     SHOALWATER OUT 10 NM-WEST ENTRANCE U.S. WATERS STRAIT OF 
     JUAN DE FUCA.

     SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 9 PM PST FRIDAY FOR 
     GRAYS HARBOR BAR.

     SMALL CRAFT ADVISORY UNTIL 9 AM PST FRIDAY FOR EAST ENTRANCE 
     U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS 
     INCLUDING THE SAN JUAN ISLANDS.

     SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 9 AM PST FRIDAY 
     FOR ADMIRALTY INLET.

&&

$$

WWW.WEATHER.GOV/SEATTLE

AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION CAN BE SEEN 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


401 
FXUS66 KPQR 120448 CCA
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 PM PST THU FEB 11 2016

.SYNOPSIS...A MILD AND MOIST SOUTHWEST FLOW PATTERN INTO NORTHWEST
OREGON AND SOUTHWEST WASHINGTON WILL INTO FRIDAY. A COLD FRONT WILL
THEN BRING COOLER TEMPERATURES AND LOWER SNOW LEVELS TO BELOW THE
CASCADES PASSES FRIDAY NIGHT AND SATURDAY. A WARM FRONT WILL SPREAD
STEADIER RAIN AND PRODUCE RISING SNOW LEVELS LATE SATURDAY AND
SUNDAY. ADDITIONAL UNSETTLED WEATHER WILL PRODUCE MORE VALLEY RAIN
AND MOUNTAIN SNOW NEXT WEEK. 

&&

.SHORT TERM...RADAR SHOWED MOST OF THE PRECIPITATION OVERRUNNING A
WARM FRONT THIS EVENING HAD LIFTED N INTO WA....LEAVING MOST OF THE
INTERIOR OF NW OREGON DRY LATE THIS EVENING. A COLD FRONT OFF THE
COAST WAS POISED TO PUSH INLAND...ACCORDING TO MOST MODELS FRI
MORNING. ON SATELLITE THE COLD FRONT APPEARED TO LACK DEEP MOISTURE
THIS EVENING AS EVIDENCED BY A LACK OF COLD TOPPED CLOUDS...BUT A
WAVE MOVING UP OFF THE S OREGON COAST SUGGESTED AT LEAST A SMALL
CHANCE FOR SOME RAIN TO MOVE BACK IN LATER TONIGHT...SO WILL NEED TO
KEEP A MENTION FOR THE POSSIBILITY OF SOME LIGHT RAIN LATE DOWN THE
S INTERIOR....BUT WITH THE BETTER CHANCES FOR RAIN REMAINING NEAR
THE COAST. 

REMAINDER OF SHORT TERM DISCUSSION UNCHANGED... A SURFACE LOW
PRESSURE IS CURRENTLY MOVING NORTHWARD ALONG 140W OFF THE PACIFIC
NORTHWEST COAST. AN ATTENDANT COLD FRONT CURRENTLY NEAR 130W WILL
PUSH EASTWARD INTO THE REGION EARLY FRIDAY. THIS WILL BRING A PERIOD
OF RAIN FRIDAY MORNING...AND ALLOW SNOW LEVELS TO LOWER TO NEAR 4500-
5000 FT FRIDAY AFTERNOON. THE SHORTWAVE TROUGH RESPONSIBLE FOR THE
LOW PRESSURE SYSTEM WILL LAG A BIT AND SKIRT OUR NORTHERN ZONES
FRIDAY NIGHT. THIS SHOULD PRODUCE AN UPTICK IN SHOWER ACTIVITY AND
ALLOW SNOW LEVELS TO LOWER FURTHER...GENERALLY INTO THE 3500-4000 FT
RANGE. SNOWFALL AMOUNTS WILL LIKELY BE GREATEST ACROSS THE SOUTH
WASHINGTON CASCADES WHERE 1 TO 4 INCHES OF SNOW APPEAR LIKELY.
FARTHER SOUTH...EVEN AN INCH OF NEW SNOW FRIDAY NIGHT MIGHT BE A
STRETCH IN THE LANE COUNTY CASCADES. 

ANY REMAINING SHOWERS SHOULD COME TO AN END FAIRLY QUICKLY SATURDAY
MORNING AS WEAK SHORTWAVE RIDGING TEMPORARILY SHIFTS EASTWARD ACROSS
THE REGION. HOWEVER...THE BREAK IN THE WET WEATHER WILL BE SHORT
LIVED AS A STRONG WARM FRONT WILL SPREAD CLOUDS AND STEADY RAIN INTO
THE REGION SATURDAY AFTERNOON/EVENING...AND LIKELY CONTINUE TO BRING
RAIN TO THE AREA FOR MUCH OF SUNDAY. COLDER AIR WILL LIKELY BE SLOW
TO PUSH OUT OF THE CASCADES SATURDAY NIGHT. GIVEN MODEL QPF...THERE
APPEARS A GOOD CHANCE THAT PORTIONS OF THE SOUTH WASHINGTON CASCADES
AND PERHAPS THE NORTH OREGON CASCADES ABOVE 4000-5000 FT WILL SEE
ENOUGH SNOW...SOMEWHERE ON THE ORDER OF 4 TO 8 INCHES...TO RESULT IN
WINTER WX ADVISORIES SATURDAY NIGHT. HOWEVER...IMPACTS TO TRAVEL
SHOULD BE SHORT LIVED AS SNOW LEVELS SHOULD RISE TO 7000 FT OR HIGHER
ON SUNDAY. /NEUMAN 

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. SUNDAY NIGHT
THROUGH THURSDAY...THE PROGRESSIVE WEATHER PATTERN WILL PERSIST INTO
NEXT WEEK. MODELS CONTINUE TO SHOW A FLAT UPPER LEVEL RIDGE MOVING
OVER THE PAC NW EARLY NEXT WEEK. THIS COULD BRING A BRIEF BREAK FROM
THE RAIN MONDAY...BUT WILL MAINTAIN SOME CHANCE POPS IN THE FORECAST
DUE TO LINGERING INSTABILITY. A WEAK SHORTWAVE DISTURBANCE LOOKS TO
RIDE OVER THE TOP OF THE RIDGE ON TUESDAY AND WILL LIKELY PUSH
ANOTHER FRONT ACROSS THE REGION LATE TUESDAY/EARLY WEDNESDAY
BRINGING MORE RAIN. CASCADE SNOW LOOKS TO RETURN WEDNESDAY AFTERNOON
WITH SNOW LEVELS LOWERING TO AROUND 3500 FT. UNSETTLED WEATHER AND
LOWERING SNOW LEVELS CONTINUE INTO THURSDAY AS THE BASE OF THE
TROUGH MOVES ACROSS THE FORECAST AREA.
MONDAY WILL LIKELY BE THE WARMEST DAY...WITH TEMPS TRENDING COOLER
EARLY NEXT WEEK. /64

&&

.AVIATION...CIGS AND VIS IN THE CENTRAL AND SOUTH VALLEY HAVE
DROPPED TO MOSTLY IFR THIS EVENING AND EXPECT THAT TO CONTINUE
TONIGHT. WINDS OUT OF THE EAST IN THE NORTH VALLEY SHOULD KEEP VFR
CONDITIONS IN PLACE NEAR THE GORGE BUT EXPECT CONDITIONS FROM KHIO
NORTH AND WEST TO BE MOSTLY IFR TONIGHT. THE COAST WILL LIKELY
HAVE MVFR CIGS OR VIS THROUGH FRIDAY MORNING. EXPECT MVFR VSBYS
AND POSSIBLY MVFR CIGS WITH A WEAK FRONT FRIDAY MORNING...THEN
RISING TO VFR IN THE AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS WITH RAIN AND MID TO HIGH
CLOUDS. GUSTY WINDS OUT OF THE EAST NEAR THE COLUMBIA RIVER GORGE
AND AROUND KTTD. BOWEN

&&

.MARINE...THE BUILDING LONG-PERIOD NW SWELL WILL DOMINATE THE
WATERS TONIGHT AND PEAK AROUND 14 FT BY FRIDAY MORNING. SEAS WILL
STAY ABOVE 10 FT THROUGH THE WEEKEND. A LOW-END SMALL CRAFT
ADVISORY FOR WINDS CONTINUES TONIGHT...HOWEVER THERE IS STILL
SOME CONCERN THAT AREAS WITHIN 10 NM WILL NOT SEE FREQUENT GUSTS
ABOVE 20 KT. BEST CHANCE FOR INCREASED GUSTS WILL BE LATER
TONIGHT WHEN THE FRONT NEARS. THERE IS A CHANCE FOR GALE FORCE
GUSTS LATE IN THE WEEKEND. BOWEN/TJ

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST FRIDAY FOR WATERS 
     FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
     WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST SUNDAY 
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
     60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST FRIDAY FOR COASTAL 
     WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10 NM-
     COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST
     SATURDAY.

&&

$$
		
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


165 
FXUS66 KPDT 120344
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
744 PM PST THU FEB 11 2016

.SHORT TERM...WARM FRONT MOVING ACROSS THE NORTHERN PORTION OF THE
FORECAST AREA THIS EVENING WITH SOME LIGHT RAIN. SHOULD EXIT THE
REGION BY LATE EVENING. SATELLITE INDICATES PARTLY TO MOSTLY
CLOUDY SKIES FOR THE REMAINDER OF THE NIGHT. UPPER LEVEL TROUGH
AND COLD FRONT MOVE THROUGH ON FRIDAY WITH ADDITIONAL RAIN AND
MOUNTAIN SNOW. NEXT SYSTEM LOOKS FAIRLY STRONG AND WILL BRING
DECENT PRECIPITATION SATURDAY NIGHT INTO SUNDAY NIGHT. RAINFALL
AMOUNTS COMBINED WITH WARM AIRMASS WILL RESULT IN SIGNIFICANT
RIVER RISES SUNDAY THROUGH TUESDAY. 94

&&

.PREV DISCUSSION... /ISSUED 353 PM PST THU FEB 11 2016/ 

SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...A WARM FRONT
ASSOCIATED WITH THE NEXT PACIFIC SYSTEM IS CURRENTLY MOVING NORTH
ACROSS THE PACIFIC NORTHWEST. THIS FRONT WILL CONTINUE TO MOVE
THROUGH NORTHEAST OREGON AND SOUTHEAST WASHINGTON LATE THIS
AFTERNOON AND EARLY THIS EVENING. THUS WILL SEE LIGHT SHOWERS
GRADUALLY LIFT NORTH OUT OF MUCH OF THE AREA BY MID EVENING. A FEW
SHOWERS SHOULD LINGER OVER THE NORTHERN BLUES, NEAR THE OREGON
CASCADES AND OVER PORTIONS OF SOUTHEAST WASHINGTON OVERNIGHT. LOW
LEVEL INVERSIONS WILL CONTINUE OVER PORTIONS OF THE BASIN, AND SOME
PATCHY FOG WILL AGAIN BE POSSIBLE OVERNIGHT INTO FRIDAY MORNING.
THUS WILL ALSO CONTINUE THE CURRENT AIR STAGNATION ADVISORIES. THE
COLD FRONT ASSOCIATED WITH THIS NEXT SYSTEM WILL MOVE ACROSS THE
REGION FRIDAY AFTERNOON AND EVENING. THIS SYSTEM WILL SPREAD MORE
PRECIP ACROSS THE AREA. WILL SEE SNOW LEVELS LOWER BEHIND THE FRONT.
ALSO SHOULD SEE WINDS OVER PORTIONS OF THE AREA INCREASE BEHIND THE
FRONT. A FEW SHOWERS WILL LINGER SATURDAY OVER THE MOUNTAINS.
MEANWHILE SHOULD SEE BREEZIER WINDS AND BETTER MIXING AT MOST
LOCATIONS, THOUGH MIXING MAY REMAIN LIMITED IN THE YAKIMA AND
KITTITAS VALLEYS. ANOTHER WARM FRONT IS EXPECTED TO MOVE ACROSS THE
REGION SATURDAY NIGHT BRINGING ANOTHER ROUND OF PRECIP. SNOW LEVELS
SATURDAY NIGHT WILL RUN AROUND 4000 FEET. 90 

LONG TERM...SUNDAY THROUGH THURSDAY...A WEST TO NORTHWEST FLOW WILL
PROVIDE AMPLE MOISTURE AS A SERIES OF DISTURBANCES RIDE OVER AN
OFFSHORE RIDGE. THIS WILL LEAD TO A CHANCE FOR MAINLY RAIN SHOWERS
AT TIMES. SUNDAY WILL SEE A COLD FRONT CROSS THE AREA AS A RIDGE
BUILDS OFFSHORE. SNOW LEVELS WILL REMAIN AROUND 4000 FEET IN THE
MORNING THEN RISE TO 6000-7000 FEET IN THE AFTERNOON. THIS WILL GIVE
US A CHANCE OF RAIN ACROSS THE AREA AND THE MOUNTAINS WILL HAVE A
CHANCE OF OF UP TO AN INCH OR TWO OF SNOW IN THE MORNING. THE
STRENGTHENING OFFSHORE RIDGE WILL LIFT THE FRONT NORTH OUT OF THE
AREA SUNDAY NIGHT WITH A CONTINUED CHANCE OF RAIN IN THE MOUNTAINS
AND A SLIGHT CHANCE IN THE LOWER ELEVATIONS. MONDAY THROUGH TUESDAY
THE RIDGE WILL DEFLECT SYSTEMS TO OUR NORTH AND WE WILL BE DRY ASIDE
FROM A CHANCE OF SHOWERS ALONG THE CASCADE CREST AND A SLIGHT CHANCE
OF SHOWERS IN THE EASTERN MOUNTAINS. TUESDAY AND TUESDAY NIGHT AN
APPROACHING TROUGH WILL PUSH THE RIDGE ACROSS OUR AREA AND OFF TO
THE EAST. MODELS DIFFER AS TO WHEN A FRONT ASSOCIATED WITH THE
TROUGH WILL CROSS THE AREA. THE GFS BRINGS IT IN WEDNESDAY AND
WEDNESDAY NIGHT WITH THE TROUGH MOVING THROUGH BEHIND THE FRONT ON
THURSDAY. THE ECMWF HAS A STRONGER SYSTEM FURTHER SOUTH WITH IT
MOVING INTO THE AREA WEDNESDAY NIGHT AND THURSDAY. BOTH SITUATIONS
WOULD MEAN A CHANCE OF RAIN ACROSS THE AREA WITH SNOW LEVELS AROUND
6000-7000 FEET INITIALLY BEFORE DROPPING TO 3000-4000 FEET WITH THE
TROUGH PASSAGE. HAVE LEANED TOWARDS THE GFS TIMING AND HAVE A CHANCE
OF RAIN WEDNESDAY THROUGH THURSDAY WITH A CHANCE OF MOUNTAIN SNOW IN
ADDITION BY THURSDAY. TEMPERATURES SUNDAY WILL BE IN THE LOWER TO
MID 50S WITH MID 40S TO MID 50S IN THE MOUNTAINS. WITH THE INFLUENCE
OF THE OFFSHORE RIDGE TEMPERATURES WILL SOAR MONDAY AND TUESDAY TO
UPPER 50S TO MID 60S WITH UPPER 40S AND 50S IN THE MOUNTAINS. A FEW
PLACES MAY SEE RECORD HIGH TEMPERATURES ON THESE DAYS. WEDNESDAY AND
THURSDAY WILL DROP BACK THE 50S WITH MAINLY 40S IN THE MOUNTAINS.
PERRY

AVIATION...00Z TAFS...VFR CONDITIONS WILL BE PREDOMINANT FOR THE
NEXT 24 HOURS. A WARM FRONT IS CROSSING THE AREA THIS EVENING AND
WILL BRING OCCASIONAL SHOWERS MAINLY TO THE NORTHERN HALF OF THE
AREA THROUGH 03Z-05Z AFFECTING ALL TAF SITES EXCEPT KRDM, KBDN AND
KPSC. ANOTHER DISTURBANCE WILL BRING MORE SHOWERS AFTER 15Z-18Z
TOMORROW MORNING AFFECTING ALL TAF SITES. CEILINGS WILL BE BKN-OVC
AT 4000-10000 FEET AGL IN GENERAL, THOUGH KYKM AND KDLS MAY GET MVFR
CEILINGS AND VISIBILITIES DUE TO FOG FROM 11Z-18Z. KDLS MAY ALSO GET
MVFR CEILINGS WITH -SHRA FROM 16Z-21Z. WINDS WILL REMAIN BELOW 15
KTS FOR THE NEXT 24 HOURS. PERRY

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  40  52  39  53 /  30  40  50  10 
ALW  43  52  43  53 /  30  40  50  20 
PSC  39  51  38  56 /  30  40  30  10 
YKM  38  48  33  52 /  50  40  20  10 
HRI  40  52  39  56 /  30  40  40  10 
ELN  33  44  33  46 /  60  50  20  20 
RDM  36  56  31  52 /  10  30  30  10 
LGD  38  51  34  49 /  30  20  40  20 
GCD  38  54  33  50 /  10  20  30  10 
DLS  41  54  40  54 /  40  50  30  20 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST SATURDAY FOR ORZ041-044-
     050-505-507-508-510.

WA...AIR STAGNATION ADVISORY UNTIL 10 AM PST SATURDAY FOR WAZ024-
     026>029-520-521.

&&

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

$$

94

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

Northeastern Washington and Northern Idaho


315 
FXUS66 KOTX 112358
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
358 PM PST THU FEB 11 2016

.SYNOPSIS... 
A warm front lifts into the Inland Northwest through tonight.
This will spread a chance of rain across much of the area. Snow
will generally fall only in the higher mountains. The exception
will be in the valleys near the north Cascades. A cold front
passes later Friday, with continued precipitation chances and
slightly lower snow levels. Unsettled weather will continue
through the weekend into early next week with valley rain, high
mountain snow and breezy winds expected. Temperatures will be
quite mild on Monday with many locations seeing highs in the mid
50s to low 60s.


&&

.DISCUSSION...
Tonight through Saturday: The Inland NW will be in a wetter
pattern as a frontal wave moves through the region. Tonight a warm
front draped across southern WA and the lower ID Panhandle lifts
toward the northern mountains. Deepening and moistening isentropic
ascent will lead to broad precipitation threat across the Inland
NW this evening. However the highest risk will be along and north
of I-90 and lowest toward the Palouse into the L-C Valley.
Precipitation will largely fall as rain in the valleys, leaving
snow for the higher mountains. The main exception remains near the
Methow Valley where the warm air is not too deep and precipitation
may fall as a rain/snow mix or all snow. This may result in an
inch or so of snow through the night. Otherwise models don't show
the precipitation to be too significant in terms of amounts, with
most areas seeing somewhere around a tenth of an inch through
Friday morning. Also, while PoPs will be relatively high, the
precipitation may be periodic, meaning it doesn't look organized
enough to say the entire period will see steady rain. Between the
precipitation there will be the potential for fog. Yet confidence
in coverage and intensity in low, so it left as patchy.

Going into Friday the warm front lingers near the northern-tier,
while a cold front comes toward the Cascades in the afternoon. In
the morning some models show drier air across south-central and
southeastern WA and the lower Panhandle. Others are not as ready
to bring drier air in. A threat of precipitation will continue
across region, however the highest risk across the Cascades and
northern mountain zones. Between Friday afternoon and evening the
cold front crosses the Cascades and advances toward the ID/WA
border. This will revitalize the threat of precipitation The
Cascades will seeing the highest risk in the afternoon, while
chances wane there through the evening. Chances will increase
farther east through the afternoon and peak in the evening.
Between late evening and overnight the broader threat retreats to
the mountains, while the lowlands dry out. The incoming cold front
will also lead to some breezy conditions by Friday afternoon,
generally highest over south-central to southeastern WA into the
Idaho Palouse. Speeds on the order of 5 to 15 mph with gusts to 25
mph will be possible.

On Saturday an upper trough continues to migrate through the
eastern third of WA and north ID early, while the next warm front
starts to impinge on the Cascades in the afternoon. This set-up
will keep the the threat of showers alive across the region. With
the highest risk in the Cascades and the northeast WA and ID
Panhandle mountains, as well the rising terrain over the eastern
Columbia Basin. The lowest risk will be in the lee of the Cascades
and deeper Columbia Basin. Winds will be a bit stronger Saturday
afternoon, especially south-central and southeast and eastern-
central Washington into the Idaho Palouse. Speeds of 10 to 20 mph,
with gusts to 30 mph will be possible. This should allow for most
areas to come out of the Air Stagnation Advisory. The main
exception will be near the Cascade valleys/Okanogan Valley where
winds and mixing will be less. /J. Cote'

Saturday night through Thursday...The models are in relatively
good agreement through about 12z Wednesday before breaking down
Wednesday and Thursday. Zonal flow or weak ridging will be over
the region through the forecast period. The westerly flow will tap
into deep Pacific moisture with several weak waves that are
expected to move through the main flow. This will result in a warm
and fairly wet forecast through the extended period. Snow levels
Saturday night will be around 3k feet for the north and 4k feet
across the south, but rapidly increase by Sunday afternoon to 5-6k
feet and to 6-7k feet by Monday. So the higher elevations of the
Cascades and the northern and Panhandle mountains could see 3-6
inches of wet snow Saturday night, otherwise precipitation will be
as rain with high elevations snow the remainder of the week.
Precipitation amounts from Saturday night through Tuesday could
reach 0.25-0.50 for the lower elevations and 0.50-1.00 or a littlemore
for the mountains. Near the Cascade crest 1.0 to 1.5 inches will
be possible. Temperatures on Sunday will be in the 40s and 50s,
which will be about 5 degrees above normal. Then the temperatures
will increase Monday and Tuesday by another 5-10 degrees. The warm
temperatures and rain will almost certainly result in good snow
melt and rises on area rivers.

We will have to pay special attention to Monday. Temperatures are 
expected to 10-15 degrees above normal and dew points will be
well into the 40s and 50s. A surface low will develop east of the
Continental Divide and with weak surface high pressure along the
coast the surface gradient will increase. In addition 850mb winds
will increase to around 35-40kts. This will result in southwest
winds 20-30 mph with gust 30-40 mph across the mountain tops, the
Columbia basin and the Palouse area. Gusty winds, warm
temperatures and high dew points will result in rapid snow melt.
The focus will be across the Waterville Plateau, some of he
mountain valleys, and across the Idaho Palouse where the low
elevation snow will likely melt at a rapid rate. Model hydrographs
show rapid rises on almost all rivers and streams, but areas of
concern will be the Palouse basin, and the Coeur D'Alene basin
where the rivers may bump up against action stage. Up on the
Waterville Plateau there is plenty of snow to melt and run off.
Palisades creek will see some significant rises. In addition snow
melt will likely cause nuisance flooding along secondary roads and
especially in area where culverts cross the road. We will issue a
hydrologic outlook to keep up with situational awareness through
the weekend.

Wednesday and Thursday...The models break down as far as
consistency goes. Some models try to bring an upper level trough
through the region late Wednesday and Thursday, while others want
to under-cut the ridge with the low going into California ans
still others have something some where in between. I chose to keep
a low end chance of rain or showers in the forecast for now with
temperatures cooling off but remaining above normal. Tobin 

&&

.AVIATION... 

00Z TAFS: A warm front will move north through the forecast area
tonight...deepening the moisture over the region and increasing
the chance for light rain at the TAF sites. Light rain currently
falling across the western zones will slowly track east across the
region through the evening. Conditions will be mainly VFR ahead of
and with the precipitation. Behind the rain stratus and fog
development lower cigs/vsby to MVFR and possible IFR early Friday
morning. Conditions improving back to VFR for most areas after
18z Friday. Tobin


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        38  47  34  45  35  46 /  60  50  60  40  60  40 
Coeur d'Alene  37  47  36  45  34  45 /  60  60  70  60  70  60 
Pullman        41  53  38  47  37  49 /  30  50  70  40  90  60 
Lewiston       43  57  41  54  42  55 /  20  30  50  30  80  50 
Colville       34  40  33  43  33  41 /  80  80  50  50  60  30 
Sandpoint      34  40  34  41  33  40 /  80  80  90  60  70  60 
Kellogg        36  42  35  39  33  40 /  70  60  90  80  90  80 
Moses Lake     38  49  34  51  37  52 /  50  50  20  10  40  20 
Wenatchee      34  44  33  46  33  46 /  80  40  20  10  50  30 
Omak           35  42  30  41  30  39 /  80  60  20  20  40  20 

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until 10 AM PST Saturday for Moses Lake 
     Area-Northeast Mountains-Okanogan Highlands-Upper Columbia 
     Basin-Waterville Plateau-Wenatchee Area.

     Air Stagnation Advisory until 10 AM PST Tuesday for East Slopes 
     Northern Cascades-Okanogan Valley.

&&

$$

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