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

Western Washington


339 
FXUS66 KSEW 190406
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
905 PM PDT FRI APR 18 2014

.SYNOPSIS...A FRONT WILL MOVE THROUGH THE AREA SATURDAY. SHOWERS 
WILL TAPER OFF SATURDAY NIGHT AND SUNDAY. ANOTHER FRONT WILL AFFECT 
THE AREA SUNDAY NIGHT AND MONDAY. THE WEATHER WILL REMAIN COOL AND 
UNSETTLED THROUGH THROUGH THE END OF NEXT WEEK. 

&&

.SHORT TERM...WEAK HIGH PRESSURE TONIGHT AND THEN THE NEXT VIGOROUS 
FRONTAL SYSTEM WILL MOVE THROUGH THE AREA SATURDAY FOR ANOTHER ROUND 
OF BREEZY WET WEATHER. SHOWERS SAT WILL TAPER OFF SAT NIGHT INTO 
SUNDAY AS HIGH PRESSURE BUILDS INTO THE AREA. ANOTHER FRONTAL 
SYSTEM  WILL MOVE TO AREA SUN NIGHT OR MON MORNING. THE FRONT WILL 
STALL AND PIVOT N-S ALONG THE COAST...GIVING RAIN ON THE COAST AND A 
CHANCE OF RAIN FOR THE INTERIOR. THERE WILL BE A CHANCE OF SHOWERS 
MONDAY AS AN UPPER TROUGH MOVES TOWARD THE AREA.

.LONG TERM...LONG TERM MODELS GENERALLY SHOW PROGRESSIVE SHORT WAVE 
SYSTEMS MOVING THROUGH THE AREA TUE AND WED GIVING A CHANCE OF 
SHOWERS AT TIMES. A MORE WELL DEFINED FRONT APPEARS THAT IT WILL 
MOVE ACROSS THE AREA THU OR THU NIGHT. WHILE THERE WILL BE A 
TENDENCY FOR CONDITIONS TO BE UNSETTLED...THE TIMING OF INDIVIDUAL 
FEATURES IS UNCERTAIN WITH THE ECMWF AND GFS SHOWING SOME TIMING 
DIFFERENCES. WILL SHOW HIGHER POPS FOR THU THAN THE OTHER DAYS IN 
THE EXTENDED...BUT OVERALL THE LONG TERM FORECAST WILL BE A BROAD 
BRUSH. ALBRECHT 

&&

.HYDROLOGY...RIVER FLOODING IS UNLIKELY FOR THE NEXT 7 DAYS. 

THE EXCEPTION IS THE NORTH FORK OF THE STILLAGUAMISH RIVER EAST OF 
THE SR 530 LANDSLIDE NEAR OSO WHERE A FLOOD WARNING REMAINS IN 
EFFECT UNTIL FURTHER NOTICE. FLOODING CONTINUES FOR THIS RIVER AS A 
RESULT OF WATER POOLED BEHIND THE DEBRIS DAM THAT PARTIALLY BLOCKS 
THE RIVER.

AT 3 PM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON IS AT 
5.6 FT...OR 4200 CFS AND IS FALLING. IT IS EXPECTED TO FALL TO 
AROUND 4.5 FT EARLY SAT AFTERNOON THEN RISE BACK UP TO 5.2 FT MIDDAY 
SUNDAY BEFORE RESUMING A FALL BACK DOWN TO AROUND 4 FT EARLY NEXT 
WEEK. SIMILAR TRENDS ARE EXPECTED ON THE NORTH FORK OF THE 
STILLAGUAMISH NEAR OSO AND AT THE SR 530 SLIDE POOL TO THE EAST OF 
THE LANDSLIDE.  ALBRECHT 

&&

.AVIATION...UPPER LEVEL HIGH PRESSURE QUICKLY SHIFTS EWD TONIGHT. A 
TROUGH WILL MOVE THROUGH WRN WA SATURDAY. THE ASSOCIATED SURFACE 
FRONT REACHES THE COAST BY LATE MORNING...THEN PUSHES THROUGH 
INTERIOR WRN WA MIDDAY TO EARLY SATURDAY AFTERNOON. LIGHT SE FLOW 
ALOFT...BECOMING MODERATE SW FLOW ALOFT LATE TONIGHT AND SATURDAY.

SCT-BKN MID AND HIGH CLOUD TONIGHT. CIGS WILL LOWER TO 3-5K FT AS 
RAIN DEVELOPS LATE MORNING/EARLY AFTERNOON AHEAD OF THE FRONT. SLY 
WINDS ALSO PICKING UP AREAWIDE DURING THIS PERIOD. THE FRONT WILL 
PUSH THROUGH PUGET SOUND ROUGHLY 20Z (1PM). 

KSEA...SCT CLOUDS AT 4-5K FT AND BKN AT AROUND 15-20K FT. N-NE WINDS 
TONIGHT 4-8 KTS...THEN SE BY SATURDAY MORNING. WINDS SWITCHING SWLY 
10-14 KT AFTER 20Z SAT. DTM

&&

.MARINE...SURFACE HIGH PRESSURE OVER THE WATERS TODAY WILL SHIFT E 
TONIGHT. A COLD FRONT WILL MOVE THROUGH THE COASTAL WATERS SAT 
MORNING AND THROUGH THE INLAND WATERS MIDDAY TO EARLY AFTERNOON WITH 
SMALL CRAFT ADVISORY WINDS EXPECTED OVER ALL WATERS. HIGH PRESSURE 
WILL REBUILD ON SUNDAY. A WEAKER SYSTEM WILL ARRIVE LATER MONDAY OR 
MONDAY NIGHT. 

A LARGE SWELL TRAIN BEHIND THE COLD FRONT ON SATURDAY WILL ARRIVE 
ALONG THE WASHINGTON COAST SATURDAY NIGHT AND CONTINUE INTO SUNDAY. 
SWELLS IN THE 16 TO 19 FOOT RANGE ARE EXPECTED. HIGH SURF CONDITIONS 
ARE POSSIBLE ON THE COAST SATURDAY NIGHT INTO EARLY SUNDAY. THIS IS 
A RAZOR CLAM DIG WEEKEND FOR TWIN HARBORS...COPALIS AND MOCLIPS 
BEACHES. DTM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WARNING REMAINS IN EFFECT FOR THE NORTH FORK OF THE       
     STILLAGUAMISH RIVER EAST OF THE SR 530 LANDSLIDE. 

PZ...SMALL CRAFT ADVISORY ALL WATERS LATE TONIGHT THROUGH SATURDAY 
NIGHT. 
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR SATURDAY NIGHT.


&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR THE GRAPHICAL AFD...VISIT
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


180 
FXUS66 KPQR 190417
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR 
917 PM PDT FRI APR 18 2014

.SYNOPSIS...A PACIFIC FRONTAL SYSTEM WAS OFF THE COAST...AND WILL
APPROACH THE COAST LATE TONIGHT AND MOVE THROUGH SOUTHWEST WASHINGTON
AND NORTHWEST OREGON ON SATURDAY. THE FRONT WILL BE EAST OF THE 
CASCADES BY LATE SATURDAY AFTERNOON OR EARLY SATURDAY EVENING. 
SHOWERS WILL DECREASE SATURDAY NIGHT AS THE PARENT UPPER TROUGH 
MOVES EAST AS WELL. WEAK HIGHER PRESSURE WILL MOVE IN SUNDAY FOR 
GENERALLY DRY WEATHER ON EASTER...EXCEPT SOME MOISTURE MAY BRUSH THE 
FAR NORTH COAST ZONES. THE NEXT FRONT WILL BECOME NORTH SOUTH 
ORIENTED SUNDAY NIGHT AND STALL OFF THE COAST AS ENERGY DIGS TOWARD 
CALIFORNIA FOR MORE MOSTLY DRY WEATHER...BUT THEN MOVE ONSHORE 
MONDAY AND TUESDAY FOR MORE RAIN OR SHOWERS. THE REMAINDER OF NEXT 
WEEK LOOKS UNSETTLED AS MORE PRECIPITATION MOVES IN AT TIMES.
&&

.SHORT TERM...TONIGHT THROUGH MONDAY...AFTER A DRY DAY TODAY... 
ATTENTION TURNS TO THE NEXT FRONTAL SYSTEM THAT IS OFF THE COAST AND 
WILL APPROACH THE COAST LATE TONIGHT. HIGHER CLOUDS WILL CONTINUE TO 
INCREASE OVER THE AREA AND LOWER OVERNIGHT...AND THIS WILL LIKELY 
PREVENT MUCH IF ANY FOG OR LOW CLOUDS FROM FORMING LATER TONIGHT. 
PRECIPITATION WILL BE CLOSE TO THE COAST BY LATE TONIGHT.

THE FRONT AND THE PRECIPITATION WILL MOVE THROUGH SOUTHWEST
WASHINGTON AND NORTHWEST OREGON SATURDAY. EXPECT PRECIPITATION TO 
BEGIN ACROSS THE INLAND AREAS FAIRLY EARLY IN THE MORNING...SO 
OVERALL SATURDAY WILL BE PRETTY WET MOST AREAS. THE FRONT WILL BE 
EAST OF THE CASCADES BY EVENING...AND POSSIBLY BY LATE AFTERNOON. 
PRECIPITATION AMOUNTS SHOULD REMAIN ON THE MODEST SIDE...BUT ALL 
AREAS SHOULD GET SOME MEASURABLE PRECIPITATION.

THE UPPER TROUGH MOVES THROUGH IN THE LATE AFTERNOON AND EARLY
EVENING AND MAY BRUSH THE NORTHERN AREAS...SAY NORTH OF ABOUT SALEM
AND TILLAMOOK OR PERHAPS A BIT NORTH OF THAT WITH A FEW MORE SHOWERS
THAN FARTHER SOUTH...THEN THE SHOWERS SHOULD DRAMATICALLY DECREASE
ALL AREAS THE REMAINDER OF SATURDAY NIGHT. 

A FLAT UPPER RIDGE WILL BRING GENERALLY DRY WEATHER TO MOST OF THE
FORECAST AREA ON EASTERN SUNDAY. SOME MOISTURE MAY BRUSH THE SOUTH
WASHINGTON COAST WITH A FEW SHOWERS LATER SUNDAY...BUT THIS IS NOT
CERTAIN.

THE NEXT FRONT STALLS OFF THE COAST SUNDAY NIGHT...BECOMING MORE
NORTH TO SOUTH ORIENTED AS ENERGY FROM THE PARENT UPPER TROUGH DIGS
SOUTH TOWARD CALIFORNIA. THE SYSTEM THEN BEGINS TO PUSH ONSHORE
MONDAY AND ESPECIALLY MONDAY NIGHT WITH MORE SHOWERS. THE MODELS ARE 
LOOKING CONVECTIVE IN THE INCREASING SOUTHERLY FLOW ALOFT...WHICH IN 
APRIL BEGINS TO LOOK MORE LIKE A THUNDERSTORM PATTERN. MODEL LIFTED 
INDICES FALL BELOW ZERO OVER THE CASCADES AND IN CENTRAL OREGON LATE 
MONDAY AND MONDAY EVENING...SO WE MAY NEED TO CONSIDER ADDING 
THUNDER TO OUR CASCADE ZONES FOR LATE MONDAY AND MONDAY EVENING AS 
WE GET CLOSER TO THIS EVENT. TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MONDAY NIGHT THROUGH THURSDAY...FLOW CONTINUES TO AMPLIFY SUNDAY
NIGHT AND THIS WILL ORIENT THE COLD FRONT OFFSHORE MORE NORTH TO
SOUTH...THUS ANY PRECIPITATION WILL REMAIN WELL OFFSHORE SUNDAY
NIGHT. THE COLD FRONT FINALLY GETS A SHOVE AS THE UPPER JET NOSES
INTO THE AREA. PRECIPITATION IS MAINLY TIED TO THE FRONT...BUT WITH
THE MARGINALLY UNSTABLE SW FLOW...MODELS SHOW THAT THERE COULD BE
SOME SHOWERS IN THE AFTERNOON MAINLY FOR THE CASCADES...AS MID LEVEL
LAPSE RATES HOVER IN THE 6 TO 7 DEG/KM RANGE. INSTABILITY PARAMETERS
ARE NOT THAT IMPRESSIVE...SO THUNDER POTENTIAL LOOKS LOW AT THIS
TIME.

LOOKS LIKE TUE AND WED WILL BE CHARACTERIZED BY COOL AND DAMP
CONDITIONS AS THE DEEP UPPER LOW MIGRATES ACROSS THE PAC NW AND INTO
THE NRN ROCKIES. AFTER THE FIRST LARGE UPPER TROUGH CLEARS LATE
TUESDAY NIGHT AND MAYBE A BREAK IN SHOWERS WEDNESDAY...ANOTHER DEEP
UPPER LOW WILL SPREAD SEVERAL WAVES OF SHOWER ACTIVITY THROUGH THE
AREA FOR THE LATTER HALF OF THE WEEK.. /KMD
&&

.AVIATION...VFR PREVAILING THROUGH MOST OF TONIGHT. A COLD FRONT IS
FORECAST TO REACH THE COAST AROUND MID MORNING SAT...AND TO THE
INTERIOR VALLEYS AROUND MIDDAY. EXPECT MVFR CIGS AROUND 12Z-15Z SAT
AT THE COAST AND 18Z-20Z SAT AT INLAND TAF SITES. CONDITIONS TRENDING
TOWARD VFR LATER SAT AFTERNOON.

KPDX AND APPROACHES...VFR EXPECTED THROUGH EARLY SAT MORNING THEN
MVFR CIGS BECOMING LIKELY BY 18Z SAT AS A COLD FRONT APPROACHES THE
AREA.
&&

.MARINE...A RELATIVELY QUIET PERIOD THIS EVENING WITH WEAK HIGH OVER
THE WATERS. THE HIGH PRES GIVES WAY TO A FRONT LATER TONIGHT WHICH
SHOULD BRING SMALL CRAFT ADVISORY WINDS OVER ALL WATERS LATER TONIGHT
AND SAT. COULD SEE SOME GUSTS 30-35 KT AS THE FRONT MOVES
THROUGH...MOVING ASHORE AROUND SUNRISE SAT. WINDS THEN DIMINISH FROM
SOUTH TO NORTH SAT AFTERNOON AND NIGHT.

A LARGE SWELL TRAIN WILL FOLLOW THE FRONT SAT EVENING INTO SUN. SEAS
APPEAR ON TRACK TO RAPIDLY BUILD TO 17 TO 20 FT AT 16 SECONDS AROUND
11 PM SAT NIGHT...PEAKING BETWEEN MIDNIGHT AND 5 AM SUN. SEAS WILL
SLOWLY SUBSIDE SUN MORNING BUT REMAIN IN THE 13 TO 16 FT RANGE
THROUGH SUN NIGHT...AND TO 10 FT LATE MON. A SMALL CRAFT ADVISORY FOR
SEAS HAS BEEN ISSUED FOR THIS SWELL TRAIN.

A HIGH SURF ADVISORY CONTINUES FOR LATER SAT NIGHT THROUGH SUN
MORNING FOR THE SOUTH WASHINGTON AND NORTH OREGON COASTS. THE CENTRAL
COAST WILL PROBABLY REMAIN JUST UNDER ADVISORY CRITERIA.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH SURF ADVISORY FROM 10 PM SATURDAY TO 10 AM PDT SUNDAY FOR 
     NORTH OREGON COAST.

WA...HIGH SURF ADVISORY FROM 10 PM SATURDAY TO 10 AM PDT SUNDAY FOR 
     SOUTH WASHINGTON COAST.

PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 AM TO 9 PM PDT SATURDAY 
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
     OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM SATURDAY TO 6 
     AM PDT MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
     FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 2 AM TO 4 PM PDT SATURDAY 
     FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60
     NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 5 AM TO
     10 AM PDT SATURDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM TO
     11 PM PDT SATURDAY.

&&

$$

MORE WEATHER INFORMATION ONLINE AT...
    HTTP://WEATHER.GOV/PORTLAND

INTERACT WITH US VIA SOCIAL MEDIA
    WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
    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


532 
FXUS66 KPDT 190230
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
733 PM PDT FRI APR 18 2014

.SHORT TERM...SATELLITE SHOWS CIRRUS INCREASING OVER THE REGION THIS 
EVENING AHEAD OF THE NEXT APPROACHING WEATHER SYSTEM. EXPECT PARTLY 
CLOUDY SKIES OVERNIGHT. EVEN WITH THE CLOUD COVER TEMPERATURES WILL 
BE COLD TONIGHT AS THE AIRMASS IS FAIRLY DRY AND SURFACE DEW POINTS 
ARE LOW. MOST LOCATIONS WILL BE IN THE 30S. AN UPPER LEVEL TROUGH 
WILL PUSH A COLD FRONT THROUGH THE AREA SATURDAY. MAIN IMPACT WILL 
BE INCREASED WINDS IN THE AFTERNOON AND EVENING. THE COLUMBIA BASIN 
INTO CENTRAL OREGON WILL HAVE BREEZY WEST WINDS. PRECIPITATION 
SHOULD BE MOSTLY OVER THE CASCADES AND A LITTLE OVER THE BLUES. 
OTHERWISE PARTLY TO MOSTLY CLOUDY SKIES EXPECTED.  94

&&

.PREV DISC... /ISSUED 230 PM PDT FRI APR 18 2014/ 

SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...WEAK RIDGE OF HIGH 
PRESSURE WILL BUILD OVER THE AREA TODAY AND TONIGHT.  TEMPERATURES 
WILL BE IN THE LOWER TO MID 60S TODAY AND UPPER 60S 
TOMORROW...BEFORE ANOTHER COLD FRONT PUSHES THROUGH TOMORROW 
AFTERNOON.  BREEZY WINDS AND A CHANCE OF SHOWERS...MAINLY OVER THE 
MOUNTAINS WILL ACCOMPANY THIS FRONTAL SYSTEM.  AS THIS SYSTEM EXITS 
THE AREA...BRIEF HIGH PRESSURE WILL ONCE AGAIN RETURN SUNDAY 
MORNING.  TEMPERATURES WILL BE A BIT COOLER SUNDAY...BUT SHOULD 
STILL BE A NICE DAY...WITH HIGHS IN THE LOWER TO MID 60S.  BY MONDAY 
SOUTHWEST FLOW WILL HAVE SET IN AND TEMPERATURES ARE EXPECTED TO BE 
IN THE 70S ACROSS THE LOWER ELEVATIONS.  MOISTURE WILL BEGIN TO 
SPREAD ACROSS THE CASCADES MONDAY AFTERNOON AHEAD OF THE NEXT COLD 
FRONT.  BY MONDAY AFTERNOON AND EVENING PRECIPITATION CHANCES WILL 
INCREASE ACROSS ALL AREAS.  FOR NOW HAVE NOT ADDED THUNDER TO THE 
FORECAST...BUT WILL NOT RULE IT OUT AS A POSSIBILITY.  EXPECT THE 
COLD FRONT TO PUSH THROUGH LATE MONDAY...EARLY TUESDAY.   WEBER

LONG TERM...TUESDAY THROUGH FRIDAY NIGHT...A NEGATIVELY TILTED 
TROUGH WILL BE OVER FORECAST AREA ON TUESDAY WITH RAIN SHOWERS 
LIKELY OVER MOUNTAINS AND A GOOD CHANCE OF SHOWERS AT LOWER 
ELEVATIONS. TUESDAY NIGHT THE TROUGH MOVES INTO IDAHO/MONTANA FOR 
DECREASING POPS OVERNIGHT. WEDNESDAY HIGH PRESSURE BEGINS BUILDING 
INTO THE REGION FROM THE WEST FOR DECREASING POPS AT LOWER 
ELEVATIONS WITH A CHANCE OF SHOWERS IN MOUNTAINS THROUGH WEDNESDAY 
AFTERNOON. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT MAINLY DRY 
CONDITIONS DUE TO THE RIDGE. FRIDAY/FRIDAY NIGHT MOISTURE BEGINS 
INCREASING IN HIGHER TERRAIN FOR A CHANCE OF SHOWERS OVER MOUNTAINS. 
POLAN

AVIATION...00Z TAFS...VFR WILL OCCUR OVER THE NEXT 24 HOURS. THE 
RIDGE AXIS OF AN UPPER LEVEL RIDGE OF HIGH PRESSURE OFFSHORE MOVES 
EAST TO THE COAST BY EARLY THIS EVENING. SINKING AIR ASSOCIATED WITH 
THE RIDGE WILL KEEP DRY CONDITIONS IN PLACE EAST OF THE CASCADES 
THROUGHOUT THE FORECAST PERIOD. THE RIDGE AXIS WILL MOVE INTO 
IDAHO/MONTANA BY DAYBREAK SATURDAY, THUS ALLOWING WINDS ALOFT TO 
BACK FROM WEST TO SOUTHWEST BY DAYBREAK ON SATURDAY MORNING. 
SCATTERED HIGH CLOUDS WILL STREAM THROUGH THE RIDGE TODAY WITH CLOUD 
BASES AROUND 20000-25000 FT AGL AND THEN LOWERING TO MID LEVELS THIS 
EVENING WITH BASES BEGINNING AROUND 15000-20000 FT THIS EVENING AND 
THEN LOWERING TO 10000-15000 FT OVERNIGHT INTO SATURDAY MORNING. 
SATURDAY AFTERNOON CLOUD BASES WILL LOWER AND THICKEN TO BKN 
7000-11000 FT AGL. PRESSURE GRADIENTS HAVE WEAKENED THIS AFTERNOON. 
AS A RESULT SUSTAINED WINDS WILL BE 8-17 KTS THROUGH SUNSET AND THEN 
EARLY THIS EVENING BECOME 6-12 KTS FOR A FEW HOURS AFTER SUNSET, 
THEN BECOME DRAINAGE WINDS OF 4-8 KTS BY 05Z/19TH AND PERSIST 
THROUGH OVERNIGHT. WIND WILL INCREASE LATE SATURDAY MORNING THROUGH 
SATURDAY AFTERNOON, BECOMING 14-20 KTS BY 20Z/19TH.  POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  35  66  38  62 /   0  10  10   0 
ALW  39  67  43  62 /   0  10  10   0 
PSC  33  68  41  65 /   0  10  10   0 
YKM  33  62  36  63 /   0  10  20   0 
HRI  32  67  39  65 /   0  10  10   0 
ELN  33  61  37  61 /   0  10  20   0 
RDM  29  63  26  68 /   0  10  10   0 
LGD  32  66  35  61 /   0  20  20   0 
GCD  30  64  30  61 /   0  10  10   0 
DLS  36  65  41  65 /   0  20  20   0 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&

THREAT INDEX
SATURDAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN

GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.

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


593 
FXUS66 KOTX 182344
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
444 PM PDT FRI APR 18 2014

.SYNOPSIS... 
Clearing skies, lighter winds, and cool temperatures will be the
trend tonight. Another storm system will bring windy conditions
Saturday afternoon and night with some showers across the north.
Easter Sunday should be mild and mainly dry. After a warm and dry
Monday, a cool and unsettled weather pattern will return Tuesday 
and linger through much of the week.

&&

.DISCUSSION...
Tonight into Saturday morning: A pool of instability remains
across far northeastern WA and the northern ID Panhandle this
afternoon. Radar and satellite trends indicate at least one last
cluster of showers crossing through Boundary and Bonner Counties
then most shower activity will wane. This will lead to clearing
skies through much of the night. As for winds, pressure gradients
peaked around 12z and are slowly coming down. Afternoon mixing and
cold air advection has led to breezy to gusty winds through much
of the day but all trends will support the idea of decreasing
winds through the evening hours...becoming around 10 mph or less
overnight. Meanwhile, much drier air has settled into the region
behind this morning's cold front. The combination of these
ingredients will lead to another chilly night across the region
with most sheltered northern valleys experiences well below freezing
temperatures. 

The potential for near freezing temperatures will likely extend
into the Basin and toward the Moses Lake Area. There is not
enough confidence nor model support to issue freeze warnings based
on the coverage being more localized and a deep freeze just
experienced on the 14th. We also looked back into that event from
the 14th and dewpoints were significantly drier than today.
Nonetheless, we do anticipate temperatures to dip between 34 and
31F within the Moses Lake, Royal City, George, Ephrata, and
Beverly areas and those with sensitive plants within these
locations should prepare for near freezing temperatures but
not panic of a hard freeze. 

A few clouds will begin crossing the Cascades before 
sunrise...associated with the next frontal system but overall, 
dry conditions will prevail through Saturday morning. Any fog that
develops in the northern valleys will burn off my late morning.
/sb

Saturday afternoon through Monday...A cold front will move
through the region Saturday, bringing scattered showers to the
Inland Northwest. There is decent upper level forcing but moisture
will be the limiting factor. Showers will mainly affect the higher
elevations as there will be some dry air in the lower levels.
There may be some occasional sprinkles for the basin into the
Spokane area but the more favored areas will be the rising terrain
north and east of the basin. Strong southwest flow aloft will add
orographic ascent to the mix. Southerly flow will also bring
warmer air into the forecast area. Daytime temperatures will warm
into the 60s with low 70s for the warmer valleys. Gusty winds will
accompany the front, increasing the mixing potential for the late
afternoon/early evening period. Wind gusts of 25 to 35 mph will be
common across the basin and Waterville Plateau, spreading into the
Palouse and Spokane area. Considering the timing of the front
during the most unstable time of day, there is the possibility of
even higher wind gusts. For now, it looks like winds will remain
below advisory criteria but it will be watched closely for the
next forecast package. Diminishing winds overnight along with
clearing skies will allow for good radiational cooling. The more
sheltered northern valleys will likely dip below freezing but
areas south of I-90 will probably stay above freezing as winds
will remain elevated for much of the overnight period.

A building ridge of high pressure will keep Sunday dry except for
some lingering showers over the Idaho panhandle early in the day.
Temperatures will be near seasonal normals but not quite as warm
as Saturday's readings. Sunshine will be filtered by high clouds
moving in from the west ahead of the next Pacific system that will
start to affect the area Monday. Expect showers to spread to the
Cascade crest late Monday morning. Easterly upslope flow will
enhance lift into the east slopes for a greater chance of precip.
As winds shift to the south during the day, warm frontal precip
will spread across the western half of the forecast area Monday
afternoon and evening. Strong warm air advection will bring
temperatures above normal with most valley locations in the upper
60s to low 70s. The Lewis-Clark valley could see upper 70s and
even 80 degrees in some locations. /Kelch

Monday Night through Saturday: All eyes for the beginning of this
period will be on the system moving from west to east across the
region. The frontal system associated with the incoming trough
looks to be a rather slow mover leading to an increased time frame of
widespread precipitation. Throughout Monday night and into Tuesday
will be the best shot of precip with wetting rains expected for
most. As the trough continues to push inland on Tuesday, we expect
the associated precip to move east as well with much of the Basin
expected to dry out by late Tuesday. Rain is still expected for
far eastern WA and the Panhandle through Tuesday night as the
system slowly pushes into western Montana. The main question with
this system and also where models tend to disagree is the amount
of wrap around moisture. The GFS wraps moisture back into the
northern Panhandle and far NE WA whereas the Euro keeps it further
north late Tuesday and into Wednesday. Current trend is to follow
the GFS more as it has been more consistent over the past few runs
but this may have to be better refined as models come into better
agreement.

The next factor to monitor will be the snow levels. As the trough
center moves overhead, an abundance of associated cold air will
enter brining 850 temps down below zero for portions of our
forecast area Tuesday night into Wednesday morning. What this
means is a chance for both high and lower mountain snow with some
higher valleys even having a shot for some snowfall. Any valley
snow will likely be in the Cascades and northern WA. Impacts for
the lower areas will be minimal as none of the snow is anticipated
to stick. Higher areas will see a good shot of accumulating snow.
Snow levels rise back to more seasonal levels come daytime
Wednesday leading to valley rain and higher mountain snow.

Winds in the Tuesday and Wednesday time frame look to remain
breezy due to a tightened surface pressure gradient. Currently no
major impacts are expected, but with the cooler daytime temps, the
breeze will make it feel quite cool. Temperatures for the middle
part of the week will remain well below normal with daytime highs
staying in the 50s for most valley locations. Also the sun will
likely be hard to come by as clouds will be prominent with the
system.

Wednesday night and early Thursday looks to feature a brief break
period from the widespread rain as weak ridging builds between
the exiting and next incoming system. The mentioned next system
looks to reach the Cascades Thursday evening before spilling over
on Friday and into the weekend. Detail will have to wait for this
system as models need to come into better agreement. Overall the
period looks to be rather active with widespread rain expected.
/Fliehman

&&

.AVIATION... 
00Z TAFS: Winds will weaken this evening and the cloud cover 
will decrease as well over the aviation area. A second robust cold
front will move through the aviation area Saturday allowing
clouds to invade the sky from the south and west which will
thicken and lower with time along with some shower activity.
The most significant impact of this front passage will be another
windy interval, primarily Saturday afternoon and evening. /Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        33  63  35  59  40  67 /   0  10  10   0  10  10 
Coeur d'Alene  31  62  36  58  39  67 /  10  10  30  10  10  10 
Pullman        33  65  35  58  41  68 /   0  10  20   0   0  10 
Lewiston       36  71  41  65  45  74 /   0  10  10   0   0  10 
Colville       31  66  32  65  36  70 /  10  20  20  10  10  10 
Sandpoint      28  61  36  58  36  64 /  10  10  30  10  10  10 
Kellogg        31  62  35  57  37  66 /  10  10  30  10  10  10 
Moses Lake     32  68  38  66  43  72 /   0  10  10   0   0  10 
Wenatchee      37  64  42  66  47  68 /   0  20  10  10  10  10 
Omak           29  63  35  65  40  67 /   0  20  10  10  10  10 

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&

$$


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