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

Western Washington


540 
FXUS66 KSEW 310335 CCA
AFDSEW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT THU OCT 30 2014

CORRECTED REMARKS ABOUT SKOKOMISH RIVER IN HYDROLOGY SECTION

.SYNOPSIS...A PACIFIC FRONTAL SYSTEM WILL BRING RAINFALL TO WESTERN 
WASHINGTON TONIGHT. THE COLD FRONT WILL CROSS THE CASCADES EARLY 
FRIDAY MORNING...AND RAIN WILL TURN TO SHOWERS AND DECREASE. 
SATURDAY SHOULD BE PARTLY SUNNY WITH LIGHT SPOTTY SHOWERS. A WEAK 
FRONT WILL PROBABLY BRING SOME LIGHT RAIN ON SUNDAY. RAINY AND 
LOCALLY WINDY WEATHER IS LIKELY MOST OF NEXT WEEK.

&&

.SHORT TERM...A PACIFIC FRONTAL SYSTEM IS MOVING SLOWLY THROUGH THE 
PACIFIC NORTHWEST THIS EVENING...WITH AREAS OF RAIN CONTINUING 
ACROSS WESTERN WASHINGTON. PRECIPITATION AMOUNTS FOR THE STORM SO 
FAR HAVE BEEN ROUGHLY 0.50 TO 1.50 INCHES FOR THE COAST AND 
MOUNTAINS...WITH LOCALLY ALMOST 3 INCHES OVER THE OLYMPICS. UP TO 
0.75 INCH HAS FALLEN IN THE INTERIOR LOWLANDS. THE SNOW LEVEL IS 
STILL AROUND 7500 FT.

THE SYSTEM WILL PROGRESS SLOWLY EASTWARD WITH THE COLD FRONT 
CROSSING THE CASCADES LATE TONIGHT OR EARLY FRIDAY MORNING. STEADY 
RAIN WILL TURN TO SHOWERS...WHICH WILL PROBABLY TAPER OFF QUICKLY ON 
FRIDAY AFTERNOON. 

AN UPPER TROUGH WILL MOVE TO THE COAST LATE FRIDAY NIGHT AND INLAND 
SATURDAY. HOWEVER THE PORTION OF THE TROUGH THAT MOVES INTO WESTERN 
WASHINGTON WILL BE WEAK AND DISORGANIZED...WITH THE CORE OF THE 
UPPER TROUGH DIGGING SOUTHEAST ACROSS CALIFORNIA. A FORECAST OF 
PARTLY SUNNY SKIES AND A CHANCE OF SHOWERS LOOKS GOOD. FOR THE 
SHOWERS THAT DO OCCUR...PRECIPITATION AMOUNTS WILL BE LIGHT AND 
COVERAGE MIGHT JUST BE SCATTERED. THE SNOW LEVEL WILL BE AROUND 4500 
TO 5500 FT.

A SMALL FLAT UPPER RIDGE WILL MOVE INTO THE PACIFIC NORTHWEST 
SATURDAY NIGHT AND SUNDAY...WITH A WEAK WARM FRONT FOLLOWING CLOSELY 
BEHIND THE RIDGE AXIS. MODELS ARE HAVING DIFFICULTY WITH THE TIMING 
OF THIS SYSTEM. IT WILL BRING SOME RAIN TO WESTERN WASHINGTON ON 
SUNDAY...BUT SOME MODEL RUNS SHOW SLOWER TIMING WITH THE RAIN MOVING 
IN SUNDAY NIGHT.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON 
FORECAST DISCUSSION -- CONFIDENCE IN THIS PERIOD WAS NOT HIGH DUE TO 
CONTINUED DISAGREEMENT AND LACK CONTINUITY IN THE MEDIUM RANGE 
SOLUTIONS. IT DID APPEAR THAT WESTERN WA WILL PROBABLY RECEIVE 
SIGNIFICANT RAINFALL DURING THIS PERIOD. THE MEDIUM RANGE SOLUTIONS 
SEEMED TO BE CONVERGING ON THE IDEA OF A SIGNIFICANT RAINFALL 
PRODUCER IMPACTING THE CWA DURING THE MON/TUE TIME FRAME. HAVE KEPT 
POPS ABOVE CLIMO DURING THE EXTENDED PERIOD.

&&

.HYDROLOGY...ABOUT 1 TO 2.75 INCHES OF RAIN HAS FALLEN OVER THE 
OLYMPIC MOUNTAINS...WITH THE HEAVIEST AMOUNTS ALONG THE SOUTHEAST 
SLOPES. RADAR AND SATELLITE IMAGERY SHOW THE BACK EDGE OF THE 
HEAVIEST RAINFALL MOVING EAST OF THE OLYMPICS THOUGH...AND MODELS 
SHOW ONLY ANOTHER 0.3 TO 0.6 INCH OF RAIN IN THE SKOKOMISH BASIN 
THROUGH FRIDAY. THE SKOKOMISH RIVER NEAR POTLATCH IS RISING...AND 
ACTUALLY TRACKING SLIGHTLY AHEAD OF THE FORECAST. AFTER MUCH 
DELIBERATION I WILL GO AHEAD AND ISSUE A FLOOD WARNING THIS 
EVENING...BUT CONFIDENCE IS NOT ESPECIALLY HIGH. IT COULD FALL JUST 
SHORT OF FLOOD STAGE.
  
THE OTHER RIVER WE HAVE BEEN CONCERNED ABOUT IS THE NOOKSACK 
RIVER...BECAUSE THE OTHER FOCUS OF HEAVY RAINFALL IS AROUND MOUNT 
BAKER. FLOODING ON THE NOOKSACK LOOKS UNLIKELY THOUGH. 

FLOODING IS NOT EXPECTED ON OTHER AREA RIVERS DURING THE NEXT 7 
DAYS.   MCDONNAL

&&

.AVIATION...SW FLOW ALOFT. THE AIR MASS IS STABLE AND MOIST... 
BECOMING MORE UNSTABLE FRIDAY AS COOLER AIR MOVES IN ALOFT. THE 
HEAVIEST RAIN WITH THIS FRONTAL SYSTEM AT 8PM WAS MAINLY EAST OF I-5 
AND MOVING INTO THE CASCADES. THE RADAR SHOWS PRECIP SHOULD BECOME 
MORE SHOWERY TONIGHT AND FRIDAY. 

KSEA...A BAND OF HEAVY RAIN MOVED THROUGH THE METRO AREA THIS 
EVENING AND NOW THE RADAR SUGGESTS THE PRECIP WILL BE MORE SHOWERY. 
THE INFRARED SATELLITE IMAGE STILL SHOWS A FRONTAL BAND DRAPED OVER 
THE AREA...SO SHOWERS COULD TURN BACK TO RAIN AGAIN BUT CERTAINLY ON 
FRIDAY THE COOLER MORE UNSTABLE AIR WILL WORK IN OVER THE AREA FOR 
JUST SCATTERED SHOWERS.

&&

.MARINE...LOOKS LIKE A FRONT WENT THROUGH THE AREA WITH WESTERLIES 
IN THE STRAIT THIS EVENING...RACE ROCKS HAS BEEN UP AROUND 30KTS FOR 
A FEW HOURS...THE BUOYS AND SMITH ISLAND IN THE STRAIT HAVE NOT 
SHOWN MUCH OF THE WESTERLY PUSH...BUT WITH RACE BLOWING PRETTY 
STRONG I HAVE A SMALL CRAFT ADVISORY UP FOR THE WHOLE STRAIT FOR 
THIS EVENING. ANOTHER BREEZY SPOT AT 8PM WAS THE AREA NORTH OF 
BELLINGHAM...AND SANDY POINT HAD GUSTS TO 28MPH...BUT THE WINDS OVER 
THE WATER AND THROUGHOUT THE SAN JUANS WERE NOT MORE THAN ABOUT 
10KTS SO I DON'T HAVE AN SCA FOR THE NRN WATERS. THE WINDS OVER THE 
COASTAL WATERS BEHIND THIS FRONT SHOULD TURN TO NW 15KT 
TONIGHT...BUT THEN BECOME MORE SW AGAIN FRIDAY AS A SURFACE LOW 
PRESSURE TROUGH MOVES THROUGH THE COASTAL WATERS. WEAK HIGH PRESSURE 
WILL BUILD ACROSS WESTERN WASHINGTON SATURDAY. MORE ACTIVE WEATHER 
IS ON THE WAY SUNDAY THROUGH EARLY NEXT WEEK...WITH MORE FRONTAL 
SYSTEMS EXPECTED TO MOVE ACROSS THE WATERS. 

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WATCH IN EFFECT FROM 6 PM PDT THIS EVENING THROUGH 
      LATE FRIDAY NIGHT FOR MASON COUNTY.

PZ...SMALL CRAFT ADVISORY STRAIT OF JUAN DE FUCA TIL 11PM.

&&

$$

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


338 
FXUS66 KPQR 310415
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
915 PM PDT THU OCT 30 2014

.SYNOPSIS..STEADY RAIN ASSOCIATED WITH A MOIST FRONTAL BOUNDARY HAS
PUSHED INLAND THIS EVENING. THE STALLED FRONT WILL CONTINUE TO
PRODUCE RAIN OVERNIGHT INTO FRI MORNING...WITH THE HEAVIEST RAIN
BECOMING FOCUSED OVER THE CASCADES. THE DISSIPATING FRONT WILL PUSH
EAST OF THE CASCADES BY LATE MORNING...WITH SHOWERS REMAINING FRI
AFTERNOON BEHIND THE FRONT. EXPECT SHOWERS TO CONTAIN BRIEF HEAVY
RAIN...SMALL HAIL AND POSSIBLY SOME THUNDER. SHOWERS SHOULD BEGIN TO
TAPER OFF DURING THE EVENING HOURS FOR THOSE TRICK OR TREATING. SOME
SHOWERS MAY LINGER INTO SATURDAY...BEFORE LIGHT RAIN SPREADS BACK
ACROSS OUR NORTHERN ZONES SUNDAY AHEAD OF ANOTHER WET SYSTEM ON TAP
FOR LATE MONDAY AND TUESDAY OF NEXT WEEK. 
&&

.SHORT TERM...TONIGHT THROUGH MONDAY...WATER VAPOR SATELLITE IMAGERY
SHOWS A MOIST FRONTAL SYSTEM SPREADING ABUNDANT MOISTURE INTO THE PAC
NW. A SHORTWAVE ROTATING AROUND THE PARENT UPPER LEVEL TROUGH ON THE
SE SIDE OF THE LOW IS SLOWING THE BAROCLINIC ZONE AND PIVOTING IT
FROM A NE-SW ORIENTATION TO A N-S ORIENTATION. A BAND OF MODERATE TO
HEAVY PRECIPITATION AHEAD OF THE COLD FRONT SPREAD ONTO THE COAST
THIS AFTERNOON AND HAS PUSHED SLOWLY INLAND THIS EVENING. THERE IS 
STILL SUBTROPICAL MOISTURE FEEDING INTO THIS SYSTEM...WITH AMSU 
DERIVED SATELLITE SHOWING 1 TO 1.2 INCHES OF PRECIPITATION OVER 
WESTERN OREGON...WHICH IS SIGNIFICANTLY ABOVE NORMAL. THE SURFACE 
COLD FRONT MOVED ONSHORE OVER THE PAST SEVERAL HOURS...BUT APPEARS 
TO HAVE WEAKENED AND LOST SOME DEFINITION AS IT PASSED OVER THE 
COAST RANGE. THE STEADIER FRONTAL RAIN HAS SHIFTED EAST AND IS NOW 
FOCUSED OVER THE WILLAMETTE VALLEY AND CASCADES...WHILE THERE IS A 
BACK EDGE TO THE PRECIPITATION BAND SHOWING UP BEHIND THE FRONT 
ALONG THE COAST AND NORTHERN COAST RANGE. ANOTHER INTERESTING 
DEVELOPMENT THIS EVENING WAS A LINE OF THUNDERSTORMS THAT DEVELOPED 
OVER THE SOUTHERN AND CENTRAL OREGON CASCADES...EXTENDING INTO LANE 
COUNTY. THE LATEST RUNS OF THE SHORT TERM RAP MODEL SHOWED A STRONG 
BAND OF LOW LEVEL FRONTOGENESIS IN THIS REGION...WHICH WOULD SEEM TO 
EXPLAIN THE THUNDER. TRACKING THE RAP OVER THE NEXT FEW HOURS...IT 
APPEARS THAT THE FORCING WEAKENS AND MOVES EAST OF THE CASCADES 
AFTER MIDNIGHT. ADDED THUNDER TO THE FCST EARLIER THIS EVENING FOR 
THE CASCADES SOUTH OF MT HOOD...WITH THE THREAT ENDING AFTER 06Z.

THE FOCUS OF THE HEAVIEST PRECIPITATION WILL SHIFT MAINLY TO THE
CASCADES AND FOOTHILLS OVERNIGHT...WITH PLENTY OF SHOWERS CONTINUING
BEHIND THE FRONT. THE FRONT SHOULD DISSIPATE AND MOVE EAST OF THE
CASCADES BY MID TO LATE MORNING TOMORROW. BEHIND THE FRONT...A
SIGNIFICANTLY COLDER AND SOMEWHAT UNSTABLE AIR MASS WILL
SPREAD INTO THE AREA. EXPECT PLENTY OF SHOWERS TO DEVELOP IN THIS
POST FRONTAL AIR MASS WITH THE BRIEF HEAVY RAIN AND SMALL HAIL
POSSIBLE AS THE COLD UPPER TROUGH MOVES THROUGH THE AREA. BASED ON
THE INSTABILITY APPARENT ON SATELLITE UNDERNEATH THE UPPER
LOW...CANNOT RULE OUT A FEW RUMBLES OF THUNDER NEAR THE COAST...OR
OVER THE INTERIOR DURING THE LATE AFTERNOON. SHOWER ACTIVITY SHOULD
DECREASE SIGNIFICANTLY MOVING INTO FRIDAY EVENING.  AS THE COLDER AIR
MASS SETS IN BEHIND THE FRONT...SNOW LEVELS WILL DROP INTO THE 4500
TO 5000 FT RANGE LATE FRIDAY INTO SATURDAY. ACCUMULATIONS SHOULD
REMAIN FAIRLY LIGHT AND BELOW ADVISORY CRITERIA...THOUGH MOTORISTS
TRAVELING OVER THE HIGHER CASCADE PASSES INCLUDING SANTIAM AND
WILLAMETTE SHOULD BE AWARE OF THE POTENTIAL FOR AT LEAST ENOUGH SNOW
TO IMPACT TRAVEL LATE FRIDAY EVENING INTO EARLY SATURDAY.

THE UPPER TROUGH FINALLY SLIDES INTO THE GREAT BASIN ON SUNDAY AND
SHOWERS END AS SOME WEAK RIDGING DEVELOPS OVER THE PACIFIC NW AHEAD
OF THE NEXT SYSTEM. SOME LIGHT RAIN MAY DEVELOP OVER THE NORTHERN
ZONES AS A WEAK WARM FRONT MAY CLIP THE REGION. MORE STEADY RAIN
INCREASE LATE SUNDAY OR EARLY MONDAY AS THE NEXT FRONTAL SYSTEM
APPROACHES.  PYLE/CULLEN
&&


.LONG TERM...MONDAY THROUGH THURSDAY...A STRONGER FRONTAL SYSTEM
APPROACHES THE REGION BY MONDAY BRINGING MORE WIDESPREAD RAINFALL.
MODELS ARE IN REASONABLE AGREEMENT WITH A SYSTEM APPROACHING...BUT
SIGNIFICANT DIFFERENCES DO REMAIN IN TERMS OF THE LOCATION AND
AMOUNTS OF PRECIPITATION. SOME INDICATION THAT SOME SUBTROPICAL
MOISTURE BE ASSOCIATED WITH THIS SYSTEM...THOUGH THE PATTERN DOES
APPEAR TO STAY A BIT PROGRESSIVE IN NATURE. THEREFORE...INCREASED
POPS
THROUGH MIDWEEK AS ANOTHER WET WEEK APPEARS IN STORE. CULLEN
&&

.AVIATION...A COLD FRONT APPEARS TO HAVE SOMEWHAT STALLED AND IS
PETERING OUT OVER THE WILLAMETTE VALLEY THIS EVENING. RAIN IS
BEGINNING TO TRANSITION TO A MORE SHOWERY NATURE WITH MVFR TO VFR
CIGS. WITH NEAR CALM WINDS AT THE COAST...COULD SEE SOME MVFR VIS
DEVELOP THROUGH AT LEAST FRIDAY MORNING. MORE UNCERTAINTY INLAND
DUE TO SEEMINGLY FIZZLING FRONT. AT THIS POINT IT DOESN'T LOOK
LIKE A SIGNIFICANT WIND SHIFT WILL PROBABLY OCCUR AND IF MOISTURE
LINGERS...COULD SEE ANOTHER MORNING WITH IFR OR EVEN LIFR CIGS
AROUND SLE AND EUG. SHOWERS WILL CONTINUE THROUGH FRIDAY WITH A
SMALL CHANCE OF THUNDER MAINLY DURING THE AFTERNOON HOURS BUT
CONFIDENCE IS TOO LOW TO MENTION AT THIS POINT.


KPDX AND APPROACHES...WITH FRONT NOT MAKING A CLEAN SWEEP THROUGH
THE AREA...MVFR CIGS MAY LINGER THROUGH THE OVERNIGHT HOURS.
SLIGHT CHANCE OF THUNDER FRIDAY AFTERNOON. VFR CONDITIONS DOMINANT
BY ABOUT 18Z FRIDAY OUTSIDE OF ANY STORMS. BOWEN

&&

.MARINE...WINDS HAVE DROPPED TO 10 KT OR LESS BEHIND THE FRONT
THIS EVENING. WITH SWELL CONTINUING TO DECREASE...CONDITIONS WILL
REMAIN BENIGN OUTSIDE OF THE COLUMBIA BAR TONIGHT AND FRIDAY
MORNING BEFORE WNW SWELL INCREASES SEAS TO AT LEAST NEAR SCA
CRITERIA FRIDAY EVENING AND OVERNIGHT. RAISED SEAS TO AROUND 10 FT
BASED ON LATEST MODEL GUIDANCE...BUT SEAS FORECAST IS SOMEWHAT
UNCERTAIN AND BORDERLINE FOR SCA SO WILL LET MIDNIGHT SHIFT
REASSESS AND ISSUE IF NECESSARY. COULD SEE A COUPLE OF STORMS
FRIDAY AFTERNOON WITH ASSOCIATED LOCALIZED GUSTY WINDS. WINDS
OVERALL WILL SHIFT SOUTHERLY ON FRIDAY AND INCREASE A BIT WITH
GUSTS LESS THAN 20 KT. BOWEN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 1 AM    
    PDT FRIDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 10 AM TO 
    2 PM PDT FRIDAY.

&&


$$

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


263 
FXUS66 KPDT 310538
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1030 PM PDT THU OCT 30 2014

.SHORT TERM...LARGE UPPER LEVEL LOW APPROACHING THE PACIFIC 
NORTHWEST. COLD FRONTAL BOUNDARY LOCATED ALONG THE COAST THIS 
EVENING. AHEAD OF THIS SYSTEM SATELLITE SHOWS SKIES ARE CLOUDY 
ACROSS WASHINGTON AND OREGON. RAIN HAS BEEN FOCUSED MOSTLY ALONG THE 
CASCADES AND EAST SLOPES THIS EVENING AND WILL CONTINUE OVERNIGHT. 
SOME OF THIS MAY BE HEAVY AT TIMES ESPECIALLY OVER THE WASHINGTON 
CASCADES. THE UPPER LOW WILL SLOWLY PUSH THE COLD FRONT THROUGH THE 
REGION ON FRIDAY. RAIN WILL SPREAD EAST WITH THE FRONT. A SURFACE 
LOW WILL DEVELOP ON THE BOUNDARY FRIDAY NIGHT AND MOVE ACROSS IDAHO 
INTO MONTANA ON SATURDAY. A LARGE PRECIP SHIELD WILL DEVELOP AND 
KEEP RAIN FALLING OVER NORTHEAST OREGON AND SOUTHEAST WASHINGTON 
INTO SATURDAY. COLDER AIR MOVING IN BEHIND THE FRONT WILL MEAN SNOW 
FOR THE HIGHER MOUNTAINS ESPECIALLY THE WALLOWA AND BLUES. CLOUD 
COVER AND A COLDER AIRMASS WILL KEEP TEMPERATURES CLOSER TO NORMAL 
THE NEXT FEW DAYS WITH HIGHS MOSTLY IN THE 40S AND 50S. HAVE ADDED 
PATCHY FOG TO THE FORECAST FOR TONIGHT AND FRIDAY MORNING FOR THE 
COLUMBIA BASIN AND ADJACENT VALLEYS. LOW LEVEL INVERSION AND HIGH 
DEW POINTS INDICATE FOG COVERAGE WILL INCREASE. 94

.AVIATION...06Z TAFS. FRONTAL BOUNDARY WITH STEADY RAIN OVER CENTRAL 
OREGON/WASHINGTON WILL MOVE SLOWLY EAST TONIGHT INTO FRIDAY. LOW 
CEILINGS AND FOG WILL CREATE MVFR/IFR CONDITIONS AT MOST TAF SITES 
OVERNIGHT INTO FRIDAY. WINDS MAINLY 5-15KT.

&&

.PREV DISC... /ISSUED 225 PM PDT THU OCT 30 2014/ 

SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT. A WARM FRONT MOVED 
ACROSS AND NORTH OF THE AREA THIS MORNING TAKING MUCH OF THE RAIN 
WITH IT EXCEPT ALONG THE WA CASCADES. THE SHOWERS WILL PERSIST 
ACROSS THIS REGION UNTIL A COLD FRONT APPROACHES THE TWO STATE AREA 
TOMORROW. THE FRONT IS FORECAST TO MOVE FROM WEST TO EAST ACROSS THE 
AREA FRIDAY. SHOWERS WILL ACCOMPANY THE FRONT AS IT TRACKS ACROSS 
OUR WESTERN ZONES FRIDAY MORNING BEFORE ARRIVING ALONG THE FOOTHILLS 
OF THE BLUE MOUNTAINS FRIDAY AFTERNOON. SHOWERS ARE FORECAST TO 
SPREAD INTO THE BLUE/WALLOWAS FRIDAY NIGHT AND REMAIN ACROSS THIS 
AREA INTO SATURDAY. AS THE SHOWERS DRIFT AWAY FROM THE REGION SOME 
DRIER AIR WILL MOVE INTO OUR ENTIRE AREA SATURDAY NIGHT. 

BREEZY WEST WINDS ARE POSSIBLE FRIDAY WITH THE PASSAGE OF THE FRONT. 
MEANWHILE AFTERNOON TEMPERATURES WILL RETURN TO NEAR NORMAL THIS 
WEEKEND. 

LONG TERM...SUNDAY THROUGH THURSDAY NIGHT...DRY CONDITIONS KICK IN 
DURING THE DAYLIGHT HOURS ON SUNDAY AS HIGH PRESSURE BUILDS OVER 
REGION IN THE WAKE OF A MID/UPPER LEVEL TROUGH WHICH WILL HAVE MOVED 
INTO IDAHO/MONTANA BY DAYBREAK ON SUNDAY. DRY CONDITIONS REMAIN OVER 
REGION SUNDAY NIGHT WHILE A WARM FRONT APPROACHES THE COAST MAKING 
LANDFALL OVERNIGHT MONDAY. THE WARM FRONT BEGINS SPREADING RAIN EAST 
OF THE CASCADES MONDAY MORNING WITH RAIN MAKING AN ENTRANCE IN 
CENTRAL OREGON AND SOUTH CENTRAL WASHINGTON BY LATE AFTERNOON. 
MONDAY NIGHT THE WARM FRONT SWEEPS ACROSS FORECAST AREA BRINGING 
RAIN LIKELY AREAWIDE. THE WARM FRONT PERSISTS OVER REGION DURING 
DAYLIGHT HOURS ON MONDAY, WHICH KEEPS HIGH POPS OVER MOUNTAINS AND 
FOOTHILLS OF THE BLUE MOUNTAINS THROUGH MONDAY AFTERNOON. THE WARM 
AIR BRINGS ADDITIONAL RAIN TO MOUNTAINS MONDAY NIGHT WITH A COLD 
FRONT SWEEPING ACROSS FORECAST ON TUESDAY FOR MORE RAIN. WEDNESDAY 
AND THURSDAY HIGH PRESSURE BUILDS OVER CWA FOR MAINLY DRY 
CONDITIONS. POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  48  58  40  51 /  10  70  70  20 
ALW  50  60  44  53 /  10  70  70  30 
PSC  48  60  42  56 /  10  60  60  10 
YKM  46  57  36  55 /  70  70  20  10 
HRI  46  59  40  56 /  10  60  60  10 
ELN  45  54  36  51 /  80  70  20  10 
RDM  43  53  31  48 /  40  80  50  10 
LGD  46  60  41  46 /  10  50  70  70 
GCD  44  58  38  47 /  10  60  70  60 
DLS  50  58  42  55 /  80  80  20  10 

&&

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

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


858 
FXUS66 KOTX 310123
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
623 PM PDT THU OCT 30 2014

.SYNOPSIS...
A slow moving frontal system will slowly move through the region
over the next 2 days. Rain will push up against the Cascades
tonight...before tracking across the region Friday and Friday
night. Rain in the Idaho Panhandle will likely linger into
Saturday. Cool and unsettled weather is expected to continue into
next week.


&&

.DISCUSSION...
Quick update this evening to modify chance of precipitation
through the evening and into tomorrow morning. Radar showing some
very light showers across northeast WA and north ID. These showers
should move out of the area in the next 2 hours or so, with this
area then remaining dry the rest of the night. Other change made
was to split the chance of precipitation tomorrow morning into an
early morning and mid morning period. Models seem to agree that
the Spokane area shouldn't see any rain through the morning
commute at least...and therefore decreased chance of precip
throughout Spokane county and areas to the east and north. /Nisbet


&&
.PREV DISCUSSION... 
Tonight through Friday night...Afternoon
satellite imagery shows a deep low pressure system in the eastern
Pacific out near 135W. Current model guidance is matching up
pretty well. The low is expected to split tonight as a a short
rounds the bottom of the trough courtesy of a 130+ kt jet. With
the jet parallel to the low forward movement has been slowed. The
accompanying cold front isn't expected to cross the Cascades until
Friday evening between 00z-03z. As the trough digs the steering
flow will become increasingly southerly. The warm front eased in
from the west- northwest overnight...but as the flow becomes
increasingly southerly the warm front will retrograde back to the
west and tuck up against the east slopes of the Cascades this
evening...before slowly pushing through the forecast area Friday
afternoon.

The cold front then tracks across the remainder of the forecast
area Friday night and stalls over the Idaho Panhandle. This puts
the focus for the best precipitation to the Idaho Panhandle. The
stratiform precipitation will change to showers with the
atmosphere drying from west to east.

Precipitation: I kept the chances for precipitation west of a
line from about Republic south to about Saddle mountain Wildlife
area for most of tonight and Friday. Aiding in the precipitation
production will be light east to southeast winds which will add an
orographic lift. Rain fall amounts will range from .10 to .15 for
the lower east slopes and the deep basin to around an inch near
the Cascade crest over the next 24 hours. Snow levels are pretty
high, around 6k feet and are not expected to drop below 5k feet
until after the frontal passage Friday night. By this time the
heaviest precipitation will be winding down. But the area near the
Cascade crest could certainly pick up several inches of fresh snow
in the showers following the cold front. Further to the east
precipitation will begin later but not be quite as wet. QPF from a
couple hundredths in the deep basin to around a third of an inch
in the Blue mountains and the central Panhandle mountains early
Saturday morning. Again snow levels will start out very high in
the warm sector precipitation and not drop below 5k feet until
later Saturday morning. So precipitation should be as mostly rain.

Temps and Wind: Temperatures will bump up 3-5 degrees Friday with
southerly winds and warm air advection. Pre-frontal winds from the
east-southeast will come around to the south-southwest Friday
afternoon and increase slightly. Winds 5-10 mph with gusts to 15
mph will be common as this is not expected to be a big wind event.
/Tobin

Saturday and Sunday: A trough pattern will slowly traversing
through the region during this period. Models are in good
agreement of timing and moisture associated with this system. With
strong cyclonic flow around the apex of the trough in NW Nevada, a
strong moist flow will push into the Idaho Panhandle and western
Montana. This is expected to bring precip to the Idaho Panhandle
and extreme eastern Washington. The bulk of the precip is expected
to fall on Saturday with snow levels above 5000 feet. Areas could
receive rain totals of at least a quarter of an inch in the Cams
Prairie area and around one inch near Mullan Pass. Snow levels
drop to around 4000 feet late Saturday but the bulk of moisture
and the trough will shift further East. This will allow for light
snow accumulation in the higher elevations near Lookout Pass. The
Cascades during this period are expected to fairly dry. Spill over
from the western Washington along the Cascades will bring some
light showers to the eastern side of the Cascades but precip
amounts will fairly small. The Columbia Basin is expected to be
dry during this weekend. Temperatures for this will period will be
near the season normals. Highs will range in the upper 40s to low
50s. Lows are expected to around mid 30s with some locations
expected to cross into freezing temperatures. /JDC

Monday and Tuesday: Shortwave ridge of higher pressure breaks down
and allows another moist Pacific storm system to push across the
region. This storm system will ride a 150 +kt jet streak directed
toward Vancouver Island. Much of the upper level dynamics
associated with the jet and vorticity maximum will remain north
of the region. This will result in a surface low that tracks
across central and northern BC from Monday night into Tuesday.
Precip will develop during the day on Monday with some decent
isentropic ascent ahead of the cold front. The cold front will
then swing across the region Tuesday morning. This is will result
in approximately 12-18 hours of light to moderate precip from
Monday afternoon into Tuesday morning. All areas will see a good
chance for at least some light precip. Best accumulations are
expected across the Northeast Mtns over into the ID Panhandle with
storm totals of between 0.50 to 1.00 inches. Totals will be a bit
less out into the greater basin area with 0.25 to 0.50 inches
expected in the Spokane Area and on the Palouse; and up to a
quarter of an inch for most other locations around the region.
Snow levels will generally be up around 5,000 feet. They sill
start out a bit lower early Monday and then increase as the precip
moves in through Monday night.

Wednesday through Thursday: There will be another storm system
that moves through toward the end of the work week. A warm front
will push north across the region on Wednesday. This will result
in some light precip across the region. We may then see a little
bit of a break in the precip before the cold front pushes through
around Thursday. Models show a quick hitting cold front passage.
Strong upper level dynamics aloft looks to spin up a deepening
surface low pressure system from southern BC into southern
Alberta. This would create good packing of isobars across the
region for Thursday afternoon. Expect breezy to windy conditions
with this front. Wind highlights may be needed depending on how
strong this surface low gets. The 12Z model runs are the first to
show such strong cyclogenesis, so confidence at this point in
wind strength is low.

Expect fall like temperatures next week. Overnight low temperatures
will moderate out from the chilly temperatures expected this
weekend. /SVH

AVIATION...
00Z TAFS: The warm front has retro-graded back to the west and is
now snugged up against the Cascades...but the front is expected to
push very slowly back to the east again tomorrow. Light rain will
continue at times at KEAT through early this evening then become
more intense through the night. Conditions will very widely at
KEAT the next 24 hours from MVFR to LIFR and back. Precipitation
and a lower deck will make it to KMWH around 12z but conditions
are expected to remain VFR with a drop to MVFR at times. Further to
the east the remainder of the TAF sites will not see precipitation
begin until 18-20z Friday...again with lowering decks but
conditions mainly VFR.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        45  56  42  48  34  49 /  10  50  50  20  10  10 
Coeur d'Alene  43  58  43  46  34  48 /   0  40  50  70  40  10 
Pullman        46  59  42  46  35  48 /   0  30  60  70  40  10 
Lewiston       48  65  46  48  40  53 /   0  20  70  80  40  10 
Colville       42  55  41  50  33  50 /  40  80  50  10  10   0 
Sandpoint      39  57  41  47  35  47 /  10  40  60  70  40  20 
Kellogg        42  59  41  45  35  44 /   0  20  70 100  60  30 
Moses Lake     45  55  41  54  35  54 /  40  60  10  10  10   0 
Wenatchee      46  55  39  55  39  56 / 100  90  10  10   0  10 
Omak           43  52  37  51  34  52 /  90  90  20  10  10  10 

&&

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


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