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

Western Washington


620 
FXUS66 KSEW 031222
GPHAFD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
252 AM PDT TUE MAY 3 2016

.SYNOPSIS...STRONG ONSHORE FLOW WILL DEVELOP TODAY FOR MUCH COOLER
WEATHER COMPARED TO YESTERDAY. MEANWHILE...A LOW PRESSURE SYSTEM
ALONG OR OFF THE COAST WILL BRING SOMEWHAT UNSETTLED CONDITIONS TO
THE AREA THROUGH THURSDAY. MAX TEMPERATURES WILL BE NEAR NORMAL
WEDNESDAY AND THURSDAY. HIGH PRESSURE ALOFT WILL RETURN ON FRIDAY.

&&

.SHORT TERM...
THERE WERE SCATTERED SHOWERS OVER THE WESTERN HALF OF THE
FORECAST AREA EARLY THIS MORNING. MEANWHILE...TEMPS WILL BE MUCH
COOLER TODAY...BY ABOUT 15 TO 20 DEGREES AT MOST PLACES...AFTER
THE RECORD WARMTH EXPERIENCED ON MONDAY.

IN THE VERY NEAR TERM...EXPECT THE ONSHORE PRESSURE GRADIENT TO
STRENGTHEN DURING THE DAY TODAY FOR WELCOME RELIEF FROM THE VERY
RECENT HOT SPELL. A DEEPENING MARINE LAYER COMBINED WITH
STRENGTHENING ONSHORE FLOW WILL LIKELY KILL THE THREAT OF TSTMS
OVER MUCH OF THE AREA TODAY. THE EXCEPTION WILL BE THE CASCADES
WHERE THERE WILL BE A SLIGHT RISK OF TSTMS THIS AFTERNOON AND
EARLY EVENING.

THE PACIFIC NORTHWEST WILL BE UNDER THE INFLUENCE OF AN UPPER
LEVEL TROF CENTERED OFFSHORE THROUGH WEDNESDAY. THE UPPER TROF
AXIS WILL SHIFT OVER THE WEST COAST ON THURSDAY...HOWEVER THIS
SYSTEM WILL HAVE BECOME SPLIT BY THEN. EXPECT MUCH OF THE ENERGY TO
DIVE SOUTH...CARVING A CLOSED UPPER LEVEL LOW OFF THE CA COAST
(PIC1). THE MAIN IMPACT THIS SYSTEM WILL HAVE ON OUR WEATHER WILL BE
COOLER TEMPS AND SOMEWHAT UNSETTLED CONDITIONS. MAX TEMPS ACROSS THE
CWA WILL BE NEAR NORMAL ON WEDNESDAY AND THURSDAY.

.LONG TERM...
AN UPPER LEVEL RIDGE WILL BUILD OVER THE AREA ON FRIDAY FOR
SUNNIER AND WARMER CONDITIONS. BEYOND FRIDAY...THE LATEST GFS
SOLUTION WAS COMING MORE IN LINE WITH THE ECMWF SOLUTION OF
DIGGING AN UPPER TROF OVER WESTERN CANADA LATE THIS WEEKEND.
CONSEQUENTLY...THE GFS WAS FLATTER WITH THE RIDGE ON SATURDAY.
THE DEEPENING TROF WILL SERVE TO INITIATE AN ONSHORE PUSH ON
SATURDAY. 

TEMPS ARE ANTICIPATED TO START OFF ABOVE NORMAL AT THE BEGINNING
OF THIS PERIOD BUT LOWER TO CLOSER TO NORMAL THE END OF THE
PERIOD. THE FORECAST TEMPS REFLECTED A COMPROMISE BETWEEN THE
WARMER GFS AND THE COOLER ECMWF SOLUTIONS. IN OTHER WORDS...THERE
IS A CHANCE THAT THE FORECAST TEMPS ARE TOO WARM FOR SUNDAY AND
MONDAY.

AT THIS TIME...KEPT THE FORECAST DRY DURING THIS PERIOD BUT
CANNOT RULE OUT THE POSSIBILITY OF A FEW SHOWERS OVER THE NORTH
CASCADES EARLY NEXT WEEK.

&&

.AVIATION...SOUTHERLY FLOW ALOFT OVER WESTERN WASHINGTON EARLY
THIS MORNING...BETWEEN THE UPPER HIGH OVER THE NORTHERN ROCKY
MOUNTAINS AND OFFSHORE UPPER TROUGH ALONG 135W (PIC10). THE AIR MASS
IS SOMEWHAT MOIST ABOVE 10000 FT WITH WEAK INSTABILITY...PRODUCING
ISOLATED SHOWERS. SOUTHERLY FLOW ALOFT WITH WEAK INSTABILITY AND
INCREASING MOISTURE WILL CONTINUE THROUGH TONIGHT (PIC11). IN
ADDITION LOW LEVEL ONSHORE FLOW WILL INCREASE.

SCATTERED TO BROKEN ALTOCUMULUS ACROSS THE FORECAST AREA EARLY THIS
MORNING WITH CEILINGS MOSTLY AT OR ABOVE 10000 FT. THERE ARE
ISOLATED SHOWERS AND SCATTERED VIRGA FALLING FROM THESE CLOUDS.
MARINE STRATUS HAS MOVED NORTH UP THE COAST AND INTO THE LOWER
CHEHALIS VALLEY WITH WITH LOW-END MVFR AND LOCAL IFR CONDITIONS.
CONDITIONS SHOULD LOWER ACROSS THE FORECAST AREA TONIGHT AS MOISTURE
INCREASES ALL LEVEL.

KSEA...SOUTH WIND 3-8 KT...BECOMING SOUTHWEST 6-12 KT THIS
AFTERNOON...THEN NORTHWEST AND NORTH TONIGHT. CEILING SHOULD MOSTLY
REMAIN AT OR ABOVE 10000 FT TODAY...THEN GRADUALLY FALL TONIGHT.
MCDONNAL

&&

.MARINE...ONSHORE FLOW WILL INCREASE TODAY AND THIS EVENING
AS THE THERMAL TROUGH MOVES EAST OF THE CASCADES AND HIGH PRESSURE
BUILDS OVER THE OFFSHORE WATERS (PIC12). THERE IS A GOOD CHANCE OF
GALE WESTERLIES IN THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA
THIS AFTERNOON AND TONIGHT...WITH SMALL CRAFT ADVISORY WINDS LIKELY
OVER ALL OTHER MARINE ZONES EXCEPT PUGET SOUND AND HOOD CANAL. THE
GALE WATCH IS BEING UPGRADED TO A GALE WARNING.
ONSHORE FLOW WILL CONTINUE WEDNESDAY THROUGH FRIDAY. MCDONNAL

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING IN EFFECT FROM NOON TODAY TIL 3 AM WEDNESDAY
	 FOR THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.

 	 SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE REMAINING
	 WATERS...EXCEPT THE PUGET SOUND/HOOD CANAL...BEGINNING
	 THIS AFTERNOON.

&&

$$

WWW.WEATHER.GOV

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

Southwestern Washington and Western Oregon


868 
FXUS66 KPQR 030943
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR 
243 AM PDT TUE MAY  3 2016

.SYNOPSIS...SLOW MOVING COLD FRONT INCHING TOWARD THE COAST WILL
CONTINUE TO BRING THE THREAT OF SHOWERS TO THE REGION THROUGH
WEDNESDAY...WITH A STRAY THUNDERSTORM POSSIBLE EACH DAY IN THE
CASCADES. AS LOW-LEVEL FLOW TURNS INCREASINGLY ONSHORE...EXPECT
COOLER TEMPERATURES TO SPREAD INLAND TODAY AND WEDNESDAY. DRYING
TREND IS EXPECTED LATER IN THE WEEK AS THE REMNANTS OF THE FRONT
REORGANIZE INTO A CUTOFF LOW OVER CALIFORNIA. THIS WILL BRING A
RETURN TO OFFSHORE FLOW...WITH WARM AND DRY WEATHER THIS WEEKEND AS
HIGH PRESSURE BUILDS INTO THE PACIFIC NORTHWEST.

&&

.SHORT TERM...TODAY THROUGH THURSDAY...AFTER YET ANOTHER DAY OF
RECORD BREAKING WARMTH FOR SOME...TODAY SHOULD BE A BIT COOLER ACROSS
SW WA/NW OR AS LOW-LEVEL FLOW TURNS INCREASINGLY ONSHORE. PRESSURE
GRADIENTS HAVE FLIPPED AROUND TO ONSHORE OVER THE PAST FEW HOURS...
BOTH ON THE SYNOPTIC AND MESO SCALES. KTTD-KDLS WAS AT ABOUT +3 MB AS
OF 2 AM...WITH KOTH-KGEG GRADIENTS TURNING ONSHORE AS WELL. THIS
WILL USHER IN A COOLER AIR MASS FROM THE PACIFIC AND HIGHS TODAY
SHOULD BE A GOOD 10-20 DEGREES COOLER THAN MONDAY FOR INLAND
AREAS...AROUND 70 IN THE VALLEYS. STRENGTHENING HIGH PRESSURE OVER
THE NE PACIFIC WILL KEEP ONSHORE FLOW GOING THROUGH AT LEAST
THURSDAY...BRINGING TEMPERATURES DOWN CLOSER TO NORMAL WED/THU.

SHOWERS CONTINUE TO DEVELOP IN THE SHALLOW/WEAK INSTABILITY BETWEEN
700-500 MB THIS MORNING...BUT DESPITE BEING ELEVATED CONVECTION THE
TOPS ARE STILL GENERALLY NOT HIGH/COLD ENOUGH TO CAUSE THE REQUISITE
CHARGE SEPARATION FOR LIGHTNING. DECIDED TO LEAVE THUNDER OUT OF THE
FORECAST THIS MORNING...THOUGH A STRAY STRIKE OR TWO LIKE THE ONES
RECENTLY OBSERVED OVER THE STRAIT OF JUAN DE FUCA ARE NOT OUT OF THE
QUESTION ANYWHERE. MODEL SOUNDINGS GENERALLY SHOW LITTLE CHANGE OVER
THE NEXT 48 HOURS...WITH LIMITED INSTABILITY AT BEST ABOVE 500 MB.
SURFACE-BASED CONVECTION WILL BRING MAINLY AFTERNOON/EVENING SHOWERS
THROUGH WEDNESDAY...BUT ALSO APPEARS TOO SHALLOW FOR LIGHTNING WEST
OF THE CASCADES EITHER DAY. 

THE REMNANTS OF OUR DYING COLD FRONT/UPPER TROUGH ARE PROGGED TO
REORGANIZE INTO A CUTOFF UPPER LOW OVER CALIFORNIA BY THE END OF THE
WEEK...WHILE MOST MODELS BUILD AN UPPER RIDGE ACROSS SOUTHERN BC AND
WASHINGTON. THIS WILL GRADUALLY BRING A RETURN TO DRIER OFFSHORE FLOW
ALOFT BY THE WEEKEND...WITH THURSDAY APPEARING TO BE THE BEGINNING OF
THAT TRANSITION. SHOULD SEE SHOWERS DIMINISH AND BECOME INCREASINGLY
CONFINED TO THE CASCADES THU/FRI AS A RESULT.  WEAGLE

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY.  MODELS REMAIN IN FAIR
AGREEMENT THROUGH THE EXTENDED PERIOD AS THE UPPER LEVEL LOW
CONTINUES TO ADVANCE INTO THE GREAT BASIN WHILE AN UPPER RIDGE
BEGINS TO NOSE INTO THE PACIFIC NORTHWEST FROM THE NORTHEAST
PACIFIC. THIS WILL BRING AN END TO THE SHOWER CHANCES FOR MUCH OF
THE AREA ON FRIDAY...THOUGH WILL MAINTAIN A SLIGHT CHANCE FOR
SHOWERS OVER THE SOUTHERN PORTIONS OF THE CASCADE ZONES.
TEMPERATURES WILL WARM INTO THE WEEKEND BACK ABOVE SEASONAL NORMS
AS HEIGHTS RISE AND THE AIR MASS WARMS.   CULLEN

&&

.AVIATION...MVFR ALONG THE COAST AT 10Z AS A SOUTH WIND REVERSAL
CONTINUES. LIKELY SEEING SOME OF THE MVFR CIGS PUSHING UP THE
MAJOR COASTAL RIVER DRAINAGES. VFR ELSEWHERE. COASTAL AREAS
EXPECTED TO REMAIN MVFR THROUGH AT LEAST EARLY AFTERNOON...THEN GO
TO A MIX OF MVFR TO LOW-END VFR. INLAND AREAS WILL CONTINUE WITH
VFR BUT WITH PLENTY OF MID-LEVEL CLOUDS IN SOUTH FLOW ALOFT.
AFTERNOON HEATING TUE WILL LEAD TO A THREAT OF SHOWERS...PRIMARILY
ALONG THE CASCADES. MODELS SUGGEST MUCH DEEPER MARINE CLOUD
PENETRATION INLAND AFTER 06Z WED. 

KPDX AND APPROACHES...VFR CONDITIONS THROUGH AT LEAST 07Z WED.
PLENTY OF MID AND HIGH LEVEL CLOUDS THROUGH TUE EVENING WITH A
SLIM THREAT OF SHOWERS TUE AFTERNOON AND EVENING IN THE VICINITY.
MVFR CIGS COULD UP THE COLUMBIA RIVER TO NEAR KPDX 07Z TO 12Z WED.
WEISHAAR

&&

.MARINE...SOUTH WIND REVERSAL ALONG THE COAST EARLY THIS
MORNING...BUT MAX GUSTS HAVE BEEN UNDER 20 KT. NW TO N WIND
PATTERN RETURNS THIS AFTERNOON AND WILL BE THE DOMINANT FEATURE
OVER THE NEXT SEVERAL DAYS. LATEST MODELS IN GOOD AGREEMENT
SHOWING 20 TO 25 KT SUSTAINED SPEEDS DEVELOPING OVER THE OUTER
WATERS BY LATE THIS AFTERNOON AND CONTINUING THROUGH AT LEAST THU.
WILL GO WITH A SMALL CRAFT ADVISORY FOR WIND IN THE OUTER WATERS
BEGINNING 00Z WED. INNER WATERS WILL SEE 25 KT WIND GUSTS BEGIN A
LITTLE LATER. THUS...STARTED THE SMALL CRAFT ADVISORY THERE AT 06Z
WED. OUTER WATERS COULD SEE SMALL CRAFT ADVISORY WIND GUSTS
THROUGH THE WEEKEND. 

SEAS HAVE NUDGED DOWN A BIT SINCE EARLIER THIS EVENING...GENERALLY
6 TO 7 FT. LATEST SPECTRAL GUIDANCE SUGGEST SEAS TO BECOME WIND-
WAVE DOMINATED EARLY TUE EVENING AND CONTINUE FOR THE NEXT FEW
DAYS. OUTER WATERS LIKELY TO SEE WIND WAVES UP TO 6 FT...WITH A
LONGER-PERIOD SWELL COMPONENT OF 2-4 FT. SEAS WILL BECOME QUITE
CHOPPY AND THERE IS THE POTENTIAL FOR SQUARE SEAS LATE THIS WEEK.
WEISHAAR

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM THIS AFTERNOON TO 7 PM 
     PDT WEDNESDAY FOR WATERS FROM CAPE SHOALWATER WA TO 
     FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 11 PM THIS EVENING TO 7 PM 
     PDT WEDNESDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA 
     TO FLORENCE OR OUT 10 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM 
     PDT EARLY THIS MORNING.

&&

$$ 

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


963 
FXUS66 KPDT 031000
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
300 AM PDT TUE MAY 3 2016

.SHORT TERM...TODAY THROUGH THURSDAY...ANOTHER WARM DAY IN THE
FORECAST FOR ALL AREAS...WITH NEAR RECORD HIGH TEMPERATURES OVER THE
LOWER COLUMBIA BASIN AND THE YAKIMA VALLEY.  WARM SOUTHERLY FLOW
WILL CONTINUE TODAY AS A LOW PRESSURE SYSTEM CONTINUES TO DEEPEN OFF
THE NORTHERN CALIFORNIA COAST.  HAVE TRIMMED BACK POPS AND
THUNDERSTORM COVERAGE TO FOCUS THE CASCADE EAST SLOPES AND THE
ADJACENT VALLEYS...AS DRIER AIR LOOKS TO BE ON OUR EASTERN ZONES. 

AS THE LOW CONTINUES TO TRACK SOUTHEAST TOWARD SOUTHERN NEVADA ON
WEDNESDAY AND THURSDAY...COOLER AIR WILL INTRUDE. STILL...THERE WILL
BE MOISTURE AND INSTABILITY SPUN UP OVER THE AREA FOR ENHANCED
THUNDERSTORM COVERAGE AS WELL AS INCREASED CHANCES OF WETTING RAIN.
THUNDERSTORMS MAY EVEN CONTINUE OVERNIGHT AS THERE MAY BE SOME UPPER
LEVEL FORCING ALONG WITH MODERATE 500-300MB LAPSE RATES.  WILL KEEP
AN EYE ON THIS BUT FOR NOW JUST CONTINUING SHOWERS OVERNIGHT
WEDNESDAY NIGHT. 

BY THURSDAY THE NORTHEAST MOUNTAINS SHOULD HAVE ENOUGH RESIDUAL LOW
LEVEL MOISTURE AND FAVORABLE UPSLOPE FLOW FROM THE SOUTHEAST TO
CONTINUE THUNDERSTORMS. 500MB DIFFLUENT FLOW ALOFT COULD ALSO AID IN
AIR ACCELERATING UPWARD.  SO FOR THIS AREA...HAVE DECIDED TO GO WITH
CHANCE THUNDERSTORMS...AND A SLIGHT CHANCE WILL CONTINUE FOR THE
REST OF THE NORTHWESTERN CWA. ALTHOUGH TEMPERATURES WILL BE COOLER
BY A FEW DEGREES ON WEDNESDAY AND THURSDAY...THEY WILL STILL BE
NEAR TO SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR. WEBER 

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...A LARGE UPPER LEVEL
LOW WILL MOVE FROM CALIFORNIA ACROSS THE GREAT BASIN INTO THE
CENTRAL ROCKIES THROUGH THE FORECAST PERIOD. ON THURSDAY EVENING
THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS WITH ACTIVITY
DIMINISHING OVERNIGHT. ON FRIDAY WITH THE UPPER LOW OVER SRN
CALIFORNIA EXPECT THE THREAT FOR SHOWERS AND THUNDERSTORMS TO BE
CONFINED TO THE EASTERN THIRD OF THE FORECAST AREA. JUST THE
SOUTHERN FRINGES OF THE FORECAST AREA MAY SEE A SHOWER OR STORM ON
SATURDAY. SUNDAY THROUGH TUESDAY LOOK DRY AS NWLY FLOW DEVELOPS OVER
THE AREA. THERE WILL BE A COUPLE OF WINDY PERIODS. THE FIRST WILL BE
FRIDAY EVENING WITH GUSTY N-NELY WINDS AND THE SECOND SUNDAY EVENING
IN THE CASCADE GAPS WITH STRONG WESTERLY WINDS. TEMPERATURES WILL BE
WARMING PEAKING SUNDAY WITH HIGHS IN THE UPPER 80S COLUMBIA BASIN
THEN COOLING MONDAY AND TUESDAY TO MID 70S TO LOWER 80S LOWER
ELEVATIONS. 78

&&

.AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24
HRS. MOSTLY HIGH CLOUDS ARE EXPECTED WITH SOME MID CLOUDS ESPECIALLY
WEST. THERE WILL BE SOME CUMULUS BUILDUPS NEAR KRDM...KBDN...
KDLS...AND KYKM AFTER 21Z WITH A FEW SHRA AND POSSIBLE TSRA. FOR
THIS SET OF TAFS DO NOT PLAN ON PUTTING IN TSRA. WILL LET THE
POTENTIAL BE FINE TUNED IN LATER FORECASTS. WINDS WILL BE 5-15KT AND
A LITTLE GUSTY AT KDLS THIS AFTERNOON AND EARLY EVENING. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  85  51  77  51 /   0  10  20  50 
ALW  86  54  80  53 /   0  10  20  50 
PSC  87  55  82  56 /   0  10  20  40 
YKM  84  54  81  51 /  10  20  30  30 
HRI  86  54  79  53 /   0  10  20  40 
ELN  82  52  78  49 /  10  20  30  40 
RDM  75  45  69  43 /  30  40  60  60 
LGD  81  47  79  48 /   0  10  30  40 
GCD  79  46  77  47 /  10  10  50  60 
DLS  80  55  76  52 /  20  30  30  40 

&&

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

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

$$

89/78/78

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

Northeastern Washington and Northern Idaho


804 
FXUS66 KOTX 031143
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
443 AM PDT TUE MAY 3 2016

.SYNOPSIS...
High pressure will begin to shift east today. Expect one more day
of warm and dry conditions today. By late today and lasting until
Friday a slow moving weather disturbance will move through the
region. This will result in a cooler, unsettled pattern with a
good chance for showers and thunderstorms with locally heavy rain
by Wednesday and Thursday. Improving conditions will begin again
late on Friday, lasting into the weekend.

&&

.DISCUSSION...
LOCALLY HEAVY RAIN OVER THE CASCADES AND WESTERN BASIN POSSIBLE
THIS WEEK...FLASH FLOODING ON RECENT BURN SCARS POSSIBLE

Today through Wednesday: The weather pattern over the Inland NW will
gradually become more active as the dome of high pressure
continues to slide into central MT and southerly flow draws a rich
moisture plume into the region. The moisture will arrive along the
Cascade Crest today then begin to spread into Ern WA and N ID on
Wednesday. Consequently, the threat for showers and thunderstorms
will follow suite. Temperatures will remain quite toasty for May
standards with afternoon highs 15-20 degrees above normal today
and only cooling a handful of degrees Wednesday. The threat of
thunderstorms and showers capable of moderate rainfall amounts
will be the main focus through this period with confidence levels
near to below average regarding the threat to burn scars.

* Thunderstorm Potential: The main focus for thunderstorms this
  afternoon and evening will be along the Cascade Crest and points
  just slightly east. The combination of afternoon CAPE on the
  order of 400-800 J/kg and PWATS climbing near 0.70" does raise
  concern for cells capable of heavy downpours. Any storms that
  develop will track south to north around 20-25 mph so one storm
  will not pose as much of a threat but if several cells were
  track over the same area...this training effect could lead to
  hefty rainfall amounts. Prior to 8PM...the main forcing will
  come from converging terrain driven winds and this generally
  carries lower confidence. The threat for showers and storms will
  increase further into the evening hours as a 850-700mb frontal
  boundary arrives. The burn scar that will be most susceptible to
  heavier showers late afternoon and evening will be the Wolverine
  Complex impacting locations between Holden Village and Lucerne.
  
  The air mass will continue to slowly moisten
  across Ern WA and N ID on Wednesday but it looks like the region
  will lack a strong trigger to initiate afternoon convection.
  Just about every location across the CWA supports enough
  afternoon instability to support a thunderstorm but whether
  parcels can break through the CIN layer and develop into
  thunderstorms is highly uncertain. The main threat for any
  storms will come in the afternoon following spotty light showers
  in the morning and attm, there is loose agreement that the
  northern mountains and Cascade Crest will carry the highest
  chances. A much better opportunity arrives with a wave
  approaching from the south Wednesday night. /sb

Wednesday night through Monday...This period will consist of a wet 
showery period Wednesday night and Thursday followed by a drying
trend Friday through Sunday...with a possible breezy dry cold
front by next Monday.

The stormy period will be compliments of a moist southerly flow
visible on satellite as a deep fetch of Pacific moisture moving up
ahead of a highly meridional trough just off the coast this
morning. By Wednesday evening models are in good agreement in
depicting this deep moisture feed laying along the Cascades with
very slow movement eastward as the parent trough keeps
digging...eventually pinching off into a lazy and broad closed low
over California. A surface thermal trough will set up over the
Columbia Basin on Tuesday and Wednesday. This moisture and low
level heating will lead to an unstable air mass. Triggering
mechanisms besides orography will be provided by a weak wave
transiting up out of Oregon Wednesday night and pulling the
moisture axis eastward across the forecast area on Thursday...into
the surface thermal trough. All of this adds up to a very showery
and potentially thundery pattern Wednesday evening through Thursday
for just about the entire forecast area. The Major evolving
concern will be the potential for debris flows and flash floods on
recent burn scars in the Cascades and Okanogan area. This
potential will be closely monitored and further analyzed through
the next 24 to 36 hours for the possibility of issuing a Flash
Flood Watch for these areas.

A cooling trend will begin from west to east with the passage of
this system...with Wednesday and Thursday's high temperatures
probably still above normal but moderated off of the peak
temperatures of Tuesday.

After Thursday a drying trend will commence...still with some
lingering minor showers and perhaps a stray thunderstorm on Friday
concentrated over mountains and the southeastern zones...as a
flop-over upper ridge noses into the region over the low pressure
far to the south. This will keep the forecast area in a quiet
weather zone but with breezy north to northeast winds ushering in
some dry Canadian continental air through the Okanogan Valley and
Purcell Trench Friday and Saturday. Temperatures in this dry air
mass under clearing skies will begin to march upward again for the
weekend cresting once again around 10 degrees above normal.

Far in the extended forecast models are more ambiguous but seem to
be hinting at a dry cold front passage on or about Monday as the
polar storm track dips south and flattens the upper ridge. In
addition to breezy conditions...this time out of the
west/northwest...temperatures should moderate back toward normal
for the start of the new work week. /Fugazzi

&&

.AVIATION...
12Z TAFS: Southerly flow sandwiched between high pressure to the
east and an approaching trough will allow mid and high clouds to
stream into Central WA today then Ern WA and N ID Wed. Combined
with afternoon instability...there is a modest chance for showers
and thunderstorms 22-04Z along the Cascade Crest. Spotty light
elevated showers will expand toward KEAT/KOMK 04-12Z but given the
dry subcloud layer, main impacts through 12Z will be incr ceilings
8-10K ft AGL and spotty sprinkles. /sb


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        81  54  78  55  68  50 /   0   0  20  50  60  30 
Coeur d'Alene  82  49  78  52  69  49 /   0   0  20  50  60  30 
Pullman        79  49  76  51  67  47 /   0   0  20  50  50  40 
Lewiston       85  53  82  56  72  51 /   0  10  20  50  50  40 
Colville       87  45  79  49  70  45 /   0   0  30  50  70  30 
Sandpoint      79  44  77  48  70  44 /   0   0  20  40  60  30 
Kellogg        80  45  79  46  69  44 /   0   0  20  40  50  50 
Moses Lake     85  53  79  53  72  47 /   0  10  20  50  50  20 
Wenatchee      83  56  76  55  70  52 /  10  20  30  60  50  20 
Omak           84  53  77  54  69  48 /   0  20  40  60  60  20 

&&

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

$$

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

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