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000
FXUS66 KSEW 250331
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
830 PM PDT THU APR 24 2014

.SYNOPSIS...ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TONIGHT AND
FRIDAY WITH AN UPPER TROUGH OVER THE AREA. A FRONTAL SYSTEM WILL
BRING ANOTHER ROUND OF RAINY WEATHER SATURDAY NIGHT INTO SUNDAY. AN
UPPER RIDGE WILL BRING WARMER AND DRIER WEATHER TUESDAY ONWARDS.

&&

.SHORT TERM...SHOWERS HAVE BEGUN TO TAPER THIS EVENING WITH THE LOSS
OF DAYTIME HEATING. ISOLATED SHOWERS WILL CONTINUE TONIGHT AND
FRIDAY MORNING...THEN THERE SHOULD BE ENOUGH INSTABILITY TO CAUSE AN
UPTICK IN SHOWER ACTIVITY AGAIN FRIDAY AFTERNOON WITH AN UPPER
TROUGH OVERHEAD. ONCE AGAIN...SHOWERS SHOULD DECREASE DIURNALLY
FRIDAY EVENING...AND PRETTY MUCH COME TO AN END AFTER MIDNIGHT AS
VERY WEAK HIGH PRESSURE ALOFT BUILDS OVER THE AREA AND THE AIR MASS
BECOMES MORE STABLE. MODELS REMAIN CONSISTENT SHOWING THE NEXT
FRONTAL SYSTEM SPREADING RAIN TO THE COAST SATURDAY AFTERNOON AND
INTO THE INTERIOR SATURDAY EVENING. RAIN WILL CHANGE TO SHOWERS
SUNDAY MORNING AS THE FRONT MOVES INLAND. SUNDAY WILL BE ANOTHER
COOL AND SHOWERY DAY WITH MOIST ONSHORE FLOW BEHIND THE FRONT.
SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...A WEAK WARM FRONT MAY CLIP
WESTERN WASHINGTON ON MONDAY FOR A CHANCE OF RAIN. CONFIDENCE IS LOW
AND ANY PRECIP LOOKS LIGHT AT THIS POINT. MODELS THEN BUILD A RIDGE
OVER THE PAC NW TUE AND WED FOR A DRY AND WARM PERIOD OF WEATHER.
THE LOW LEVEL FLOW WILL FLIP OFFSHORE WITH HIGHS IN THE 60S TO
70S...ALONG WITH MOSTLY SUNNY SKIES. THE CURRENT FORECAST IS NUDGED
TOWARD THE ECMWF AND CANADIAN MODELS WHICH BOTH KEEP HIGH PRES OVER
THE REGION THROUGH NEXT WEEKEND. THE GFS BREAKS DOWN THE RIDGE ON
THURSDAY BUT THIS SOLUTION LOOKS LIKE AN OUTLIER FOR NOW. 33

&&

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

THE EXCEPTION REMAINS 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 8 PM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS AT
5.7 FT...OR 4560 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER NEAR
OSO WAS AT 217.5 FT AT 2880 CFS. THE POOL EAST OF THE SLIDE WAS
283.1 FT THIS EVENING. THE RIVER HAS CRESTED FROM HEAVY RAINS LAST
NIGHT AND WILL CONTINUE TO RECEDE.

EXPECT ISOLATED TO SCATTERED SHOWERS IN THE REGION TONIGHT AND
FRIDAY WITH RAINFALL AMOUNTS UP TO 0.25 INCHES THROUGH FRIDAY
EVENING. A COLD FRONT SATURDAY NIGHT MAY PRODUCE ANOTHER 0.50
INCHES. OTHERWISE DRY WEATHER IS FORECAST THROUGHOUT MUCH OF NEXT
WEEK.

&&

.AVIATION...MODERATE SOUTHERLY FLOW ALOFT TONIGHT WILL BECOME LIGHT
FRIDAY AS AN UPPER LEVEL TROUGH MOVES OVER THE AREA. THE AIR MASS IS
MOIST AND UNSTABLE WITH SCATTERED SHOWERS. THE AIR MASS WILL
STABILIZE OVERNIGHT AND THERE WILL BE SOME AREAS OF CLEARING. GUSTY
SOUTHWEST WINDS WILL EASE THIS EVENING. THE PRESENCE OF THE UPPER
LEVEL TROUGH WILL LEAD TO SOME INSTABILITY AND SHOWER ACTIVITY AGAIN
ON FRIDAY AFTERNOON. CEILINGS WILL BE MOSTLY VFR BUT MVFR 2-3K FT
CEILINGS ARE POSSIBLE IN SHOWERS.

KSEA...MOSTLY VFR CEILINGS OVERNIGHT EXCEPT BRIEF MVFR AROUND
SHOWERS. GUSTY SOUTHWEST WIND 10G20KT EASING TONIGHT BY 06Z. SOUTH
TO SOUTHWEST WIND 10 KNOTS OR LESS LATE TONIGHT THROUGH FRIDAY
AFTERNOON.

&&

.MARINE...SMALL CRAFT ADVISORIES REMAIN IN EFFECT OVER ALL WATERS AS
GUSTY SOUTHWEST WINDS 15-30 KT CONTINUE. WINDS WILL EASE THIS EVENING
AND MOST AREAS SHOULD BE BELOW 20 KT BY 06Z TONIGHT.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. 27

&&

.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.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
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000
FXUS66 KSEW 242205
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
305 PM PDT THU APR 24 2014

.SYNOPSIS...SHOWERS WILL CONTINUE ACROSS WESTERN WASHINGTON THIS
EVENING. AN UPPER LEVEL LOW WILL MOVE INLAND ON FRIDAY FOR ISOLATED
TO SCATTERED SHOWERS. A FRONTAL SYSTEM WILL BRING ANOTHER ROUND OF
RAINY WEATHER SATURDAY NIGHT INTO SUNDAY. AN UPPER LEVEL RIDGE WILL
BRING WARMER AND DRIER WEATHER TUESDAY ONWARDS.

&&

.SHORT TERM...EXPECT SCATTERED SHOWERS ACROSS WESTERN WASHINGTON
THIS EVENING AS AN UPPER LEVEL TROUGH AXIS SWINGS THROUGH THE AREA.
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS BETWEEN SEATTLE AND
BELLINGHAM...THERE WERE A FEW STRIKES NEAR GRANITE FALLS EARLIER.
SHOWERS WILL TAPER OFF AFTER MIDNIGHT TONIGHT.

AN UPPER LEVEL LOW WILL MOVE OVERHEAD ON FRIDAY KEEPING THE AIR MASS
COOL AND UNSTABLE. EXPECT SCATTERED SHOWERS ONCE AGAIN...MAINLY
DURING THE AFTERNOON. THIS LOW WILL WEAKEN FRIDAY NIGHT WITH SHOWERS
ENDING.

SATURDAY WILL BE MAINLY DRY...THEN WET WEATHER WILL RETURN SATURDAY
NIGHT AS THE NEXT COLD FRONT ARRIVES. THE GFS SHOWS THE FRONT ALONG
THE COAST BY 06Z...WITH PRECIP SPREADING INLAND OVERNIGHT. SHOWERS
ARE LIKELY ON SUNDAY WITH ONSHORE FLOW AND ZONAL FLOW ALOFT. TEMPS
WILL BE A FEW DEGREES COOLER WITH HIGHS IN THE LOWER 50S.

.LONG TERM...A WEAK WARM FRONT MAY CLIP WESTERN WASHINGTON ON MONDAY
FOR A CHANCE OF RAIN. CONFIDENCE IS LOW AND ANY PRECIP LOOKS LIGHT
AT THIS POINT. MODELS THEN BUILD A RIDGE OVER THE PAC NW TUE AND
WED FOR A DRY AND WARM PERIOD OF WEATHER. THE LOW LEVEL FLOW WILL
FLIP OFFSHORE WITH HIGHS IN THE 60S TO 70S...ALONG WITH MOSTLY SUNNY
SKIES. THE CURRENT FORECAST IS NUDGED TOWARD THE ECMWF AND CANADIAN
MODELS WHICH BOTH KEEP HIGH PRES OVER THE REGION THROUGH NEXT
WEEKEND. THE GFS BREAKS DOWN THE RIDGE ON THURSDAY BUT THIS SOLUTION
LOOKS LIKE AN OUTLIER FOR NOW. 33

&&

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

THE EXCEPTION REMAINS 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 WAS AT
6.1 FT...OR 5330 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER NEAR
OSO WAS AT 217.93 FT AT 3250 CFS. THE POOL EAST OF THE SLIDE WAS
283.36 FT THIS MORNING. THE RIVER HAS CRESTED FROM HEAVY RAINS LAST
NIGHT AND WILL CONTINUE TO RECEDE.

EXPECT SCATTERED SHOWERS IN THE REGION TONIGHT AND FRIDAY WITH
RAINFALL AMOUNTS UP TO 0.25 INCHES. A COLD FRONT SATURDAY NIGHT MAY
PRODUCE ANOTHER 0.50 INCHES. OTHERWISE DRY WEATHER IS FORECAST
THROUGHOUT MUCH OF NEXT WEEK.

&&

.AVIATION...MODERATE SOUTHERLY FLOW ALOFT TONIGHT WILL BECOME LIGHT
FRIDAY AS AN UPPER LEVEL TROUGH MOVES OVER THE AREA. THE AIR MASS IS
MOIST AND UNSTABLE WITH SCATTERED SHOWERS. SATELLITE IMAGERY SHOWS A
FEW BREAKS IN THE CLOUDS. THIS PATTERN WILL CONTINUE THIS EVENING
BUT THE AIR MASS WILL STABILIZE OVERNIGHT AND THERE WILL BE SOME
CLEARING. GUSTY SOUTHWEST WINDS WILL EASE THIS EVENING. FRIDAY WILL
BE SIMILAR BUT WITHOUT THE GUSTY WINDS OF TODAY.

CEILINGS ARE MOSTLY VFR BUT MVFR 2-3K FT CEILINGS ARE POSSIBLE IN
SHOWERS. THERE COULD BE AN ISOLATED THUNDERSTORM THIS AFTERNOON.

KSEA...MOSTLY VFR CEILINGS WITH A CHANCE OF A BRIEF FALL TO MVFR
THIS EVENING. SOME CLEARING LATER THIS EVENING. GUSTY SOUTHWEST
WIND 10G20KT EASING TONIGHT. CHB

&&

.MARINE...SMALL CRAFT ADVISORIES REMAIN IN EFFECT OVER ALL WATERS AS
GUSTY SOUTHWEST WINDS 15-30 KT CONTINUE. WINDS WILL EASE THIS EVENING
AND MOST AREAS SHOULD BE BELOW 20 KT BY 06Z TONIGHT.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. CHB

&&

.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.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)







000
FXUS66 KSEW 241617
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
918 AM PDT THU APR 24 2014

.SYNOPSIS...AN UPPER LEVEL TROUGH AND ONSHORE FLOW WILL BRING MORE
SHOWERS AND GUSTY WINDS TO WESTERN WASHINGTON TODAY. AN UPPER LEVEL
LOW WILL MOVE INLAND ON FRIDAY FOR ISOLATED TO SCATTERED SHOWERS.
A FRONTAL SYSTEM WILL BRING ANOTHER ROUND OF MORE ORGANIZED
RAINFALL TO THE AREA LATER SATURDAY INTO SUNDAY MORNING.

&&

.SHORT TERM...A COLD FRONT PASSED THROUGH WESTERN WASHINGTON EARLY
THIS MORNING WITH BREEZY TO WINDY CONDITIONS ACROSS THE REGION.
EXPECT MORE SHOWERS AS THE UPPER LEVEL TROUGH AXIS SWINGS INLAND
TODAY. ISOLATED THUNDERSTORMS ARE POSSIBLE FROM SEATTLE TO
BELLINGHAM THIS AFTERNOON ALTHOUGH CONFIDENCE IS LOW. TEMPS WILL BE
IN THE MID 50S TODAY WITH A FEW SUNBREAKS. SHOWERS WILL TAPER DOWN
TONIGHT.

AN UPPER LEVEL LOW WILL MOVE OVERHEAD ON FRIDAY KEEPING THE AIR MASS
COOL AND UNSTABLE. EXPECTED SCATTERED SHOWERS...MAINLY DURING THE
AFTERNOON. THIS LOW WILL WEAKEN FRIDAY NIGHT WITH SHOWERS ENDING.

SATURDAY WILL BE MAINLY DRY...THEN WET WEATHER WILL RETURN SATURDAY
NIGHT AS THE NEXT COLD FRONT ARRIVES. THE GFS SHOWS THE FRONT ALONG
THE COAST BY 06Z...WITH PRECIP SPREADING INLAND OVERNIGHT. THE
CURRENT FORECAST IS ON TRACK. 33

.LONG TERM...PREVIOUS DISCUSSION...EXTENDED MODELS IN GOOD AGREEMENT
EARLY ON WITH THE FRONT MOVING THROUGH THE AREA SATURDAY NIGHT WITH
WEAK TROUGHINESS OVER THE AREA ON SUNDAY KEEPING SHOWERS IN THE
FORECAST. MODELS SOLUTIONS START TO DIVERGE ON MONDAY WITH THE GFS
BUILDING A WEAK RIDGE OVER THE AREA WITH A DRYING TREND. THE ECMWF
ALSO SHOWS SOME RIDGE BUT BRINGS A WARM FRONT INTO THE AREA LATER IN
THE DAY INTO MONDAY NIGHT. THE CANADIAN MODEL ALSO HAS A WARM FRONT
MOVING INTO THE AREA. WILL KEEP THE CHANCE OF RAIN FORECAST FOR
MONDAY AND MONDAY NIGHT. EXTENDED MODELS ARE IN GOOD AGREEMENT ON
TUESDAY WITH AN UPPER LEVEL RIDGE BUILDING OVER THE AREA AND LOW
LEVEL OFFSHORE FLOW DEVELOPING. THIS WILL RESULT IN HIGHS ON TUESDAY
IN THE 60S ACROSS THE ENTIRE AREA. THE MODELS DISAGREE ON WEDNESDAY
WITH THE ECMWF AND CANADIAN CONTINUING TO BUILD THE RIDGE OVER
WESTERN WASHINGTON WITH LOW LEVEL OFFSHORE FLOW WHILE THE GFS SHIFTS
THE RIDGE TO THE EAST WITH THE LOW LEVEL FLOW TURNING ONSHORE DURING
THE DAY. WITH THE LACK OF CONSISTENCY HAVE STAYED WITH THE MORE
CONSERVATIVE FORECAST OF ANOTHER DAY WITH HIGHS IN THE 60S. IF THE
ECMWF AND CANADIAN ARE RIGHT THERE IS THE POTENTIAL FOR LOWER TO MID
70S ON WEDNESDAY. FELTON

&&

.CLIMATE...AS OF 6 AM THE TOTAL PRECIPITATION SINCE FEBRUARY 1ST AT
SEATTLE-TACOMA AIRPORT IS 19.04 INCHES. THIS BREAKS THE RECORD FOR
THE WETTEST FEBRUARY...MARCH AND APRIL (FEBRUARY 1ST THROUGH APRIL
30TH) IN SEATTLE. THE OLD RECORD WAS 18.97 INCHES SET BACK IN 1972.
THIS RECORD INCLUDES THE FEDERAL BUILDING RECORDS WHICH GO BACK TO
1891. RECORDS STARTED AT SEA-TAC IN 1945. FELTON

&&

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

THE EXCEPTION REMAINS 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 9 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 5.6 FT...OR 4470 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 217.4 FT AT 2750 CFS. THE POOL EAST OF THE SLIDE WAS
281.9 FT EARLY THIS MORNING.

STEADY RAIN HAS ENDED BUT WILL CONTINUE TO SEE SHOWERS TODAY. THE
LATEST HYDROGRAPH SHOWS THE STILLAGUAMISH NEAR ARLINGTON CRESTING
CLOSE TO 6.5 FEET EARLY THIS AFTERNOON.

&&

.AVALANCHE...PREVIOUS DISCUSSION...FURTHER HEAVY SNOW AND THEN
POTENTIAL RAIN SHOULD BE SEEN IN THE MT RAINIER TO MT HOOD AREA THIS
MORNING. THIS IS VERY LIKELY TO CAUSE WET LOOSE...STORM SLAB AND
WIND SLAB AVALANCHE CONDITIONS IN THIS AREA. AN AVALANCHE WARNING
CONTINUES FOR THE MT RAINIER TO MT HOOD AREA THIS MORNING. BACK
COUNTRY TRAVEL IN AVALANCHE TERRAIN IS THIS AREA IS NOT RECOMMENDED
THIS MORNING.

SIGNIFICANT SNOW AND AVALANCHE CONDITIONS ARE ALSO EXPECTED IN OTHER
AREAS BUT THAT ARE SLIGHTLY LESS THAN WARNING CRITERIA. AVALANCHES
ARE ALSO LIKELY IN THESE OTHER AREAS AS WELL.

PLEASE VISIT NWAC.US FOR DETAILS. GKF

&&

.AVIATION...FLOW ALOFT IS SOUTHWESTERLY WITH A MOIST AND SLIGHTLY
UNSTABLE AIR MASS IN THE WAKE OF A FRONT. RADAR SHOWS SCATTERED
SHOWERS AND SATELLITE IMAGERY SHOWS BREAKS IN THE CLOUDS. THIS
PATTERN WILL CONTINUE TODAY WITH SOME FILLING IN OF OPEN AREAS BY
AFTERNOON THEN SOME CLEARING THIS EVENING. GUSTY SOUTHWEST WINDS
TODAY WILL EASE TONIGHT.

CEILINGS ARE MOSTLY VFR BUT MVFR 2-3K FT CEILINGS ARE POSSIBLE IN
SHOWERS. THERE COULD BE AN ISOLATED THUNDERSTORM THIS AFTERNOON.

KSEA...CURRENTLY IN AN OPEN AREA. MOSTLY VFR CEILINGS WITH A CHANCE
OF A DROP TO MVFR BRIEFLY. THE AFTERNOON IS LIKELY TO BE MOSTLY
CLOUDY AS A CUMULUS FIELD FORMS. GUSTY SOUTHWEST WIND 10G20KT EASING
TONIGHT. CHB

&&

.MARINE...WINDS HAVE EASED ON THE COAST AND GALE WARNINGS THERE HAVE
BEEN CHANGED TO SMALL CRAFT ADVISORIES FOR WIND 15-30 KT. ELSEWHERE
SMALL CRAFT ADVISORIES REMAIN IN EFFECT AS GUSTY SOUTHWEST WINDS
15-30 KT CONTINUE. WINDS WILL EASE THIS AFTERNOON AND MOST AREAS
SHOULD BE BELOW 20 KT TONIGHT.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. CHB

&&

.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.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)







000
FXUS66 KSEW 241316 AAA
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
615 AM PDT THU APR 24 2014...ADDED CLIMATE DATA

.SYNOPSIS...A COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS
MORNING. AN UPPER LEVEL TROUGH OFF THE COAST WILL KEEP SHOWERS IN
THE FORECAST LATER TODAY AND TONIGHT. THE TROUGH WILL MOVE INLAND
LATE FRIDAY INTO FRIDAY NIGHT. ANOTHER FRONTAL SYSTEM WILL BRING
ANOTHER ROUND OF MORE ORGANIZED RAINFALL TO THE AREA LATER SATURDAY
INTO SUNDAY MORNING.

&&

.SHORT TERM...SATELLITE IMAGERY SHOWS WARM FRONT EAST OF THE AREA
WITH THE TRAILING COLD FRONT MOVING INTO THE WESTERN WASHINGTON
INTERIOR AT 10Z. TEMPERATURES WITH THE RAIN AND CLOUD COVER ARE IN A
NARROW RANGE...MID 40S TO LOWER 50S AT 3 AM.

COLD FRONT WILL MOVE INTO THE CASCADES EARLY THIS MORNING. PLENTY OF
POST FRONTAL SHOWER ACTIVITY EVIDENT ON THE SATELLITE IMAGERY. AS
THE FRONT MOVES INTO THE CASCADES THE KOLM-KBLI GRADIENT WILL
INCREASE RAPIDLY. WITH A LACK OF WESTERLIES THROUGH THE STRAIT THIS
WILL RESULT IN BREEZY...15 TO 25 MPH...WINDS IN THE INTERIOR TODAY.
SHOWER ACTIVITY DECREASING SOMEWHAT THIS AFTERNOON. GFS MOS HAS 40
PERCENT CHANCE OF THUNDERSTORMS FOR SEATTLE. BUFR SOUNDING INDICATE
LIFTED INDEXES ABOVE ZERO...AROUND PLUS 2...THIS AFTERNOON WITH VERY
LITTLE CAPE OF SHEAR. THE CONVECTIVE TEMPERATURES ARE IN THE LOWER
50S SO A RUMBLE OF THUNDER CAN NOT BE RULED OUT BUT FOR NOW THE
CHANCES TO NOT LOOK HIGH ENOUGH TO MENTION IN THE FORECAST. AIR MASS
OVER THE AREA REMAINING COOL WITH 850 MB TEMPERATURES NEAR 0C
KEEPING DAYTIME HIGHS BELOW NORMAL TODAY...IN THE LOWER TO MID 50S.

NOT MUCH CHANGE IN THE PATTERN OVERNIGHT WITH THE UPPER LEVEL
TROUGH MOVING CLOSER TO THE COAST AND SOUTHWESTERLY FLOW ALOFT
CONTINUING. AIR MASS REMAINING SLIGHTLY UNSTABLE TO KEEP A CHANCE OF
SHOWERS IN THE FORECAST. WITH THE POSSIBILITY OF SOME BREAKS IN THE
CLOUD COVER TONIGHT AND THE COOL AIR MASS REMAINING OVERHEAD LOW
TEMPERATURES IN THE COLDER LOCATIONS WILL GET DOWN INTO THE MID 30S.
FOR THE REMAINDER OF THE AREA UPPER 30S AND LOWER 40S WILL BE
COMMON.

UPPER LEVEL TROUGH MOVING INLAND OVER WESTERN WASHINGTON FRIDAY. JET
WELL TO THE SOUTH OF WESTERN WASHINGTON SO IT WILL TAKE SOME DAY
TIME HEATING TO INCREASE THE SHOWER ACTIVITY ACROSS THE AREA.
TEMPERATURES ALOFT STILL COOL WITH THE 850 MB TEMPERATURES STILL
AROUND 0C MAKING FOR ANOTHER DAY OF BELOW NORMAL HIGH TEMPERATURES
...LOWER TO MID 50S.

TROUGH AXIS MOVING EAST OF THE AREA BY LATE FRIDAY NIGHT WITH THE
SHOWER ACTIVITY DRYING UP OVER THE AREA OVERNIGHT. JET WELL SOUTH OF
THE AREA WITH THE TROUGH BECOMING SLIGHTLY NEGATIVELY TILTED. THIS
WILL SLOW THE EASTWARD MOVEMENT OF THE TROUGH DOWN SO HAVE LEFT SOME
LOW CHANCE POPS IN THE FORECAST FOR THE POSSIBILITY OF THE TROUGH
AXIS HANGING UP OVER THE AREA FRIDAY NIGHT. ANOTHER COOL NIGHT IN
STORE...MID 30S TO LOWER 40S...WITH NO MODERATION OF THE
TEMPERATURES ALOFT.

SOME INCONSISTENCIES IN THE TIMING OF THE NEXT ORGANIZED FRONT TO
REACH THE AREA. THE GFS AND THE ECMWF ARE THE FASTER
SOLUTIONS...WITH RAIN FROM ABOUT PUGET SOUND WESTWARD SATURDAY
AFTERNOON. THE NAM IS SLOWER KEEPING THE PRECIPITATION OFFSHORE
UNTIL SATURDAY NIGHT. FLOW ALOFT ACROSS THE EASTERN PACIFIC IS ZONAL
ON SATURDAY WHICH FAVORS THE FASTER SOLUTIONS WHICH ARE CURRENTLY IN
THE FORECAST.

.LONG TERM...EXTENDED MODELS IN GOOD AGREEMENT EARLY ON WITH THE
FRONT MOVING THROUGH THE AREA SATURDAY NIGHT WITH WEAK TROUGHINESS
OVER THE AREA ON SUNDAY KEEPING SHOWERS IN THE FORECAST. MODELS
SOLUTIONS START TO DIVERGE ON MONDAY WITH THE GFS BUILDING A WEAK
RIDGE OVER THE AREA WITH A DRYING TREND. THE ECMWF ALSO SHOWS SOME
RIDGE BUT BRINGS A WARM FRONT INTO THE AREA LATER IN THE DAY INTO
MONDAY NIGHT. THE CANADIAN MODEL ALSO HAS A WARM FRONT MOVING INTO
THE AREA. WILL KEEP THE CHANCE OF RAIN FORECAST FOR MONDAY AND
MONDAY NIGHT. EXTENDED MODELS ARE IN GOOD AGREEMENT ON TUESDAY WITH
AN UPPER LEVEL RIDGE BUILDING OVER THE AREA AND LOW LEVEL OFFSHORE
FLOW DEVELOPING. THIS WILL RESULT IN HIGHS ON TUESDAY IN THE 60S
ACROSS THE ENTIRE AREA. THE MODELS DISAGREE ON WEDNESDAY WITH THE
ECMWF AND CANADIAN CONTINUING TO BUILD THE RIDGE OVER WESTERN
WASHINGTON WITH LOW LEVEL OFFSHORE FLOW WHILE THE GFS SHIFTS THE
RIDGE TO THE EAST WITH THE LOW LEVEL FLOW TURNING ONSHORE DURING THE
DAY. WITH THE LACK OF CONSISTENCY HAVE STAYED WITH THE MORE
CONSERVATIVE FORECAST OF ANOTHER DAY WITH HIGHS IN THE 60S. IF THE
ECMWF AND CANADIAN ARE RIGHT THERE IS THE POTENTIAL FOR LOWER TO MID
70S ON WEDNESDAY. FELTON

&&

.CLIMATE...AS OF 6 AM THE TOTAL PRECIPITATION SINCE FEBRUARY 1ST AT
SEATTLE-TACOMA AIRPORT IS 19.04 INCHES. THIS BREAKS THE RECORD FOR
THE WETTEST FEBRUARY...MARCH AND APRIL (FEBRUARY 1ST THROUGH APRIL
30TH) IN SEATTLE. THE OLD RECORD WAS 18.97 INCHES SET BACK IN 1972.
THIS RECORD INCLUDES THE FEDERAL BUILDING RECORDS WHICH GO BACK TO
1891. RECORDS STARTED AT SEA-TAC IN 1945. FELTON

&&

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

THE EXCEPTION REMAINS 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 315 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.6 FT...OR 2820 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.4 FT AT 1800 CFS. THE POOL EAST OF THE SLIDE WAS
282.0 FT.

WITH THE STEADY RAIN COMING TO AN END OVER THE SLIDE AREA JUST SOME
SLIGHT RISES ARE EXPECTED THIS MORNING WITH THE RIVER REMAINING
STEADY THIS AFTERNOON AND EVENING. THE LATEST HYDROGRAPH SHOWS THE
STILLAGUAMISH NEAR ARLINGTON CRESTING BELOW 5 FEET. FELTON

&&

.AVALANCHE...PREVIOUS DISCUSSION...FURTHER HEAVY SNOW AND THEN
POTENTIAL RAIN SHOULD BE SEEN IN THE MT RAINIER TO MT HOOD AREA THIS
MORNING. THIS IS VERY LIKELY TO CAUSE WET LOOSE...STORM SLAB AND
WIND SLAB AVALANCHE CONDITIONS IN THIS AREA. AN AVALANCHE WARNING
CONTINUES FOR THE MT RAINIER TO MT HOOD AREA THIS MORNING. BACK
COUNTRY TRAVEL IN AVALANCHE TERRAIN IS THIS AREA IS NOT RECOMMENDED
THIS MORNING.

SIGNIFICANT SNOW AND AVALANCHE CONDITIONS ARE ALSO EXPECTED IN OTHER
AREAS BUT THAT ARE SLIGHTLY LESS THAN WARNING CRITERIA. AVALANCHES
ARE ALSO LIKELY IN THESE OTHER AREAS AS WELL.

PLEASE VISIT NWAC.US FOR DETAILS. GKF

&&

.AVIATION...FLOW ALOFT IS SOUTHWESTERLY WITH A MOIST AND STABLE AIR
MASS BECOMING SOMEWHAT UNSTABLE LATER THIS MORNING. A WARM FRONT
LIFTING NORTHWARD THROUGH PUGET SOUND AT 09Z WILL BE FOLLOWED BY A
COLD FRONT AROUND 15Z. WIDESPREAD RAIN WITH MVFR CEILINGS WILL TURN
TO SHOWERS BEHIND THE COLD FRONT WITH A GRADUAL IMPROVEMENT IN
CEILINGS TOWARD AFTERNOON. SURFACE WINDS WILL BECOME GUSTY FROM THE
SOUTH AND SOUTHWEST THIS MORNING FOLLOWING THE PASSAGE OF THE COLD
FRONT.

KSEA...MVFR CEILINGS 2-3K FT AT TIMES IN RAIN THIS MORNING. RAIN
TURNING TO SHOWERS AFTER 15Z WITH CEILINGS MOSTLY VFR THIS
AFTERNOON...EXCEPT NEAR SHOWERS. SOUTHEAST WIND 7 TO 12
KNOTS...BECOMING S-SW 15 TO 25 KNOTS AFTER 15Z AND REMAINING GUSTY
THROUGH THIS AFTERNOON.

&&

.MARINE...A WARM FRONT IS LIFTING NORTHWARD THROUGH THE INLAND
WATERS AT 09Z WITH A COLD FRONT TO FOLLOW LATER THIS MORNING. GALE
WARNINGS REMAIN IN EFFECT FOR THE COASTAL WATERS TODAY...WITH
SMALL CRAFT ADVISORIES ALL OTHER WATERS. STRONG PRESSURE RISES WILL
FOLLOW A SURFACE LOW AS IT LIFTS INTO VANCOUVER ISLAND THIS MORNING.
THIS WILL LEAD TO SOME GUSTY SOUTH OR SOUTHWEST WINDS OVER THE
INLAND WATERS MUCH OF TODAY. WINDS COULD BRIEFLY APPROACH GALE FORCE
IN PARTS OF PUGET SOUND LATER THIS MORNING.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. 27

&&

.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...GALE WARNING COAST.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)














000
FXUS66 KSEW 241047
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
345 AM PDT THU APR 24 2014

.SYNOPSIS...A COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS
MORNING. AN UPPER LEVEL TROUGH OFF THE COAST WILL KEEP SHOWERS IN
THE FORECAST LATER TODAY AND TONIGHT. THE TROUGH WILL MOVE INLAND
LATE FRIDAY INTO FRIDAY NIGHT. ANOTHER FRONTAL SYSTEM WILL BRING
ANOTHER ROUND OF MORE ORGANIZED RAINFALL TO THE AREA LATER SATURDAY
INTO SUNDAY MORNING.

&&

.SHORT TERM...SATELLITE IMAGERY SHOWS WARM FRONT EAST OF THE AREA
WITH THE TRAILING COLD FRONT MOVING INTO THE WESTERN WASHINGTON
INTERIOR AT 10Z. TEMPERATURES WITH THE RAIN AND CLOUD COVER ARE IN A
NARROW RANGE...MID 40S TO LOWER 50S AT 3 AM.

COLD FRONT WILL MOVE INTO THE CASCADES EARLY THIS MORNING. PLENTY OF
POST FRONTAL SHOWER ACTIVITY EVIDENT ON THE SATELLITE IMAGERY. AS
THE FRONT MOVES INTO THE CASCADES THE KOLM-KBLI GRADIENT WILL
INCREASE RAPIDLY. WITH A LACK OF WESTERLIES THROUGH THE STRAIT THIS
WILL RESULT IN BREEZY...15 TO 25 MPH...WINDS IN THE INTERIOR TODAY.
SHOWER ACTIVITY DECREASING SOMEWHAT THIS AFTERNOON. GFS MOS HAS 40
PERCENT CHANCE OF THUNDERSTORMS FOR SEATTLE. BUFR SOUNDING INDICATE
LIFTED INDEXES ABOVE ZERO...AROUND PLUS 2...THIS AFTERNOON WITH VERY
LITTLE CAPE OF SHEAR. THE CONVECTIVE TEMPERATURES ARE IN THE LOWER
50S SO A RUMBLE OF THUNDER CAN NOT BE RULED OUT BUT FOR NOW THE
CHANCES TO NOT LOOK HIGH ENOUGH TO MENTION IN THE FORECAST. AIR MASS
OVER THE AREA REMAINING COOL WITH 850 MB TEMPERATURES NEAR 0C
KEEPING DAYTIME HIGHS BELOW NORMAL TODAY...IN THE LOWER TO MID 50S.

NOT MUCH CHANGE IN THE PATTERN OVERNIGHT WITH THE UPPER LEVEL
TROUGH MOVING CLOSER TO THE COAST AND SOUTHWESTERLY FLOW ALOFT
CONTINUING. AIR MASS REMAINING SLIGHTLY UNSTABLE TO KEEP A CHANCE OF
SHOWERS IN THE FORECAST. WITH THE POSSIBILITY OF SOME BREAKS IN THE
CLOUD COVER TONIGHT AND THE COOL AIR MASS REMAINING OVERHEAD LOW
TEMPERATURES IN THE COLDER LOCATIONS WILL GET DOWN INTO THE MID 30S.
FOR THE REMAINDER OF THE AREA UPPER 30S AND LOWER 40S WILL BE
COMMON.

UPPER LEVEL TROUGH MOVING INLAND OVER WESTERN WASHINGTON FRIDAY. JET
WELL TO THE SOUTH OF WESTERN WASHINGTON SO IT WILL TAKE SOME DAY
TIME HEATING TO INCREASE THE SHOWER ACTIVITY ACROSS THE AREA.
TEMPERATURES ALOFT STILL COOL WITH THE 850 MB TEMPERATURES STILL
AROUND 0C MAKING FOR ANOTHER DAY OF BELOW NORMAL HIGH TEMPERATURES
...LOWER TO MID 50S.

TROUGH AXIS MOVING EAST OF THE AREA BY LATE FRIDAY NIGHT WITH THE
SHOWER ACTIVITY DRYING UP OVER THE AREA OVERNIGHT. JET WELL SOUTH OF
THE AREA WITH THE TROUGH BECOMING SLIGHTLY NEGATIVELY TILTED. THIS
WILL SLOW THE EASTWARD MOVEMENT OF THE TROUGH DOWN SO HAVE LEFT SOME
LOW CHANCE POPS IN THE FORECAST FOR THE POSSIBILITY OF THE TROUGH
AXIS HANGING UP OVER THE AREA FRIDAY NIGHT. ANOTHER COOL NIGHT IN
STORE...MID 30S TO LOWER 40S...WITH NO MODERATION OF THE
TEMPERATURES ALOFT.

SOME INCONSISTENCIES IN THE TIMING OF THE NEXT ORGANIZED FRONT TO
REACH THE AREA. THE GFS AND THE ECMWF ARE THE FASTER
SOLUTIONS...WITH RAIN FROM ABOUT PUGET SOUND WESTWARD SATURDAY
AFTERNOON. THE NAM IS SLOWER KEEPING THE PRECIPITATION OFFSHORE
UNTIL SATURDAY NIGHT. FLOW ALOFT ACROSS THE EASTERN PACIFIC IS ZONAL
ON SATURDAY WHICH FAVORS THE FASTER SOLUTIONS WHICH ARE CURRENTLY IN
THE FORECAST.

.LONG TERM...EXTENDED MODELS IN GOOD AGREEMENT EARLY ON WITH THE
FRONT MOVING THROUGH THE AREA SATURDAY NIGHT WITH WEAK TROUGHINESS
OVER THE AREA ON SUNDAY KEEPING SHOWERS IN THE FORECAST. MODELS
SOLUTIONS START TO DIVERGE ON MONDAY WITH THE GFS BUILDING A WEAK
RIDGE OVER THE AREA WITH A DRYING TREND. THE ECMWF ALSO SHOWS SOME
RIDGE BUT BRINGS A WARM FRONT INTO THE AREA LATER IN THE DAY INTO
MONDAY NIGHT. THE CANADIAN MODEL ALSO HAS A WARM FRONT MOVING INTO
THE AREA. WILL KEEP THE CHANCE OF RAIN FORECAST FOR MONDAY AND
MONDAY NIGHT. EXTENDED MODELS ARE IN GOOD AGREEMENT ON TUESDAY WITH
AN UPPER LEVEL RIDGE BUILDING OVER THE AREA AND LOW LEVEL OFFSHORE
FLOW DEVELOPING. THIS WILL RESULT IN HIGHS ON TUESDAY IN THE 60S
ACROSS THE ENTIRE AREA. THE MODELS DISAGREE ON WEDNESDAY WITH THE
ECMWF AND CANADIAN CONTINUING TO BUILD THE RIDGE OVER WESTERN
WASHINGTON WITH LOW LEVEL OFFSHORE FLOW WHILE THE GFS SHIFTS THE
RIDGE TO THE EAST WITH THE LOW LEVEL FLOW TURNING ONSHORE DURING THE
DAY. WITH THE LACK OF CONSISTENCY HAVE STAYED WITH THE MORE
CONSERVATIVE FORECAST OF ANOTHER DAY WITH HIGHS IN THE 60S. IF THE
ECMWF AND CANADIAN ARE RIGHT THERE IS THE POTENTIAL FOR LOWER TO MID
70S ON WEDNESDAY. FELTON

&&

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

THE EXCEPTION REMAINS 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 315 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.6 FT...OR 2820 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.4 FT AT 1800 CFS. THE POOL EAST OF THE SLIDE WAS
282.0 FT.

WITH THE STEADY RAIN COMING TO AN END OVER THE SLIDE AREA JUST SOME
SLIGHT RISES ARE EXPECTED THIS MORNING WITH THE RIVER REMAINING
STEADY THIS AFTERNOON AND EVENING. THE LATEST HYDROGRAPH SHOWS THE
STILLAGUAMISH NEAR ARLINGTON CRESTING BELOW 5 FEET. FELTON

&&

.AVALANCHE...PREVIOUS DISCUSSION...FURTHER HEAVY SNOW AND THEN
POTENTIAL RAIN SHOULD BE SEEN IN THE MT RAINIER TO MT HOOD AREA THIS
MORNING. THIS IS VERY LIKELY TO CAUSE WET LOOSE...STORM SLAB AND
WIND SLAB AVALANCHE CONDITIONS IN THIS AREA. AN AVALANCHE WARNING
CONTINUES FOR THE MT RAINIER TO MT HOOD AREA THIS MORNING. BACK
COUNTRY TRAVEL IN AVALANCHE TERRAIN IS THIS AREA IS NOT RECOMMENDED
THIS MORNING.

SIGNIFICANT SNOW AND AVALANCHE CONDITIONS ARE ALSO EXPECTED IN OTHER
AREAS BUT THAT ARE SLIGHTLY LESS THAN WARNING CRITERIA. AVALANCHES
ARE ALSO LIKELY IN THESE OTHER AREAS AS WELL.

PLEASE VISIT NWAC.US FOR DETAILS. GKF

&&

.AVIATION...FLOW ALOFT IS SOUTHWESTERLY WITH A MOIST AND STABLE AIR
MASS BECOMING SOMEWHAT UNSTABLE LATER THIS MORNING. A WARM FRONT
LIFTING NORTHWARD THROUGH PUGET SOUND AT 09Z WILL BE FOLLOWED BY A
COLD FRONT AROUND 15Z. WIDESPREAD RAIN WITH MVFR CEILINGS WILL TURN
TO SHOWERS BEHIND THE COLD FRONT WITH A GRADUAL IMPROVEMENT IN
CEILINGS TOWARD AFTERNOON. SURFACE WINDS WILL BECOME GUSTY FROM THE
SOUTH AND SOUTHWEST THIS MORNING FOLLOWING THE PASSAGE OF THE COLD
FRONT.

KSEA...MVFR CEILINGS 2-3K FT AT TIMES IN RAIN THIS MORNING. RAIN
TURNING TO SHOWERS AFTER 15Z WITH CEILINGS MOSTLY VFR THIS
AFTERNOON...EXCEPT NEAR SHOWERS. SOUTHEAST WIND 7 TO 12
KNOTS...BECOMING S-SW 15 TO 25 KNOTS AFTER 15Z AND REMAINING GUSTY
THROUGH THIS AFTERNOON.

&&

.MARINE...A WARM FRONT IS LIFTING NORTHWARD THROUGH THE INLAND
WATERS AT 09Z WITH A COLD FRONT TO FOLLOW LATER THIS MORNING. GALE
WARNINGS REMAIN IN EFFECT FOR THE COASTAL WATERS TODAY...WITH
SMALL CRAFT ADVISORIES ALL OTHER WATERS. STRONG PRESSURE RISES WILL
FOLLOW A SURFACE LOW AS IT LIFTS INTO VANCOUVER ISLAND THIS MORNING.
THIS WILL LEAD TO SOME GUSTY SOUTH OR SOUTHWEST WINDS OVER THE
INLAND WATERS MUCH OF TODAY. WINDS COULD BRIEFLY APPROACH GALE FORCE
IN PARTS OF PUGET SOUND LATER THIS MORNING.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. 27

&&

.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...GALE WARNING COAST.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)











000
FXUS66 KSEW 240336
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
830 PM PDT WED APR 23 2014

.SYNOPSIS...A WARM FRONT WILL BRING RAIN TONIGHT. A COLD FRONT WILL
MOVE INLAND THURSDAY MORNING. AN UPPER LEVEL TROUGH DIGGING INTO THE
PACIFIC NORTHWEST ON FRIDAY WILL KEEP SCATTERED SHOWERS IN THE
FORECAST. A THIRD FRONTAL SYSTEM WILL BRING ANOTHER ROUND OF MORE
ORGANIZED RAINFALL TO THE AREA SATURDAY NIGHT INTO SUNDAY MORNING.

&&

.SHORT TERM...RAIN HAS SPREAD ACROSS THE AREA FROM THE SOUTHWEST
THIS EVENING AS A WARM FRONT MOVES THROUGH. A TRAILING COLD FRONT
WILL MOVE INLAND THURSDAY MORNING WITH RAIN CHANGING TO SHOWERS. AN
UPPER TROUGH WILL SETTLE OVER THE REGION FRIDAY. THIS WILL KEEP A
CHANCE OF SHOWERS IN THE FORECAST BUT THERE SHOULD ALSO BE SUNSHINE
AT TIMES. ANOTHER FRONTAL SYSTEM WILL APPROACH FROM THE WEST ON
SATURDAY...WITH RAIN REACHING THE COAST IN THE AFTERNOON AND
SPREADING INTO THE INTERIOR BY EVENING. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...MOIST WESTERLY FLOW WILL KEEP A
CHANCE OF SHOWERS IN THE FORECAST ON SUNDAY. MODELS SHOW A WEAK
UPPER LEVEL DISTURBANCE TRACKING THROUGH WESTERN WA FOR SCATTERED
ACTIVITY. SHOWERS WILL DECREASE SUN NIGHT AS A RIDGE START TO BUILD
OVER THE PAC NW.

A WEAK WARM FRONT MAY CLIP WESTERN WASHINGTON ON MONDAY FOR A CHANCE
OF RAIN. THE MODELS THEN STRENGTHEN THE RIDGE OVER THE PAC NW TUE
AND WED FOR WARMER AND DRIER WEATHER. THE FORECAST LEANS TOWARD THE
ECMWF SOLUTION WHICH SHOWS AN H5 580 RIDGE OVER WA. THE LOW LEVEL
FLOW IS ALSO TURNING OFFSHORE AND WE SHOULD SEE HIGHS IN THE UPPER
60S TO 70S IF THIS PANS OUT. 33

&&

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

THE EXCEPTION REMAINS 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 8 PM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.6 FT...OR 2810 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.4 FT AT 1800 CFS. THE POOL EAST OF THE SLIDE WAS
282.2 FT THIS EVENING.

A WARM FRONT WILL BRING RAIN TONIGHT...FOLLOWED BY A COLD FRONT
THURSDAY MORNING. THIS SYSTEM WILL BRING AROUND 1.00 INCH OF
RAINFALL TO THE AREA THROUGH THURSDAY AFTERNOON. THIS IS EXPECTED TO
PRODUCE RISES ON THE STILLAGUAMISH RIVER BEGINNING THIS EVENING
THROUGH THURSDAY. THE LATEST HYDROGRAPH SHOWS THE STILLAGUAMISH NEAR
ARLINGTON CRESTING LATE THURSDAY MORNING AROUND 5 FEET.

&&

.AVALANCHE...PREVIOUS DISCUSSION...FURTHER HEAVY SNOW AND THEN
POTENTIAL RAIN SHOULD BE SEEN IN THE MT RAINIER TO MT HOOD AREA
WEDNESDAY NIGHT AND THURSDAY MORNING. THIS IS VERY LIKELY TO CAUSE
WET LOOSE...STORM SLAB AND WIND SLAB AVALANCHE CONDITIONS IN THIS
AREA. AN AVALANCHE WARNING WILL BE ISSUED FOR THE MT RAINIER TO MT
HOOD AREA FOR WEDNESDAY NIGHT AND THURSDAY MORNING. BACK COUNTRY
TRAVEL IN AVALANCHE TERRAIN IS THIS AREA IS NOT RECOMMENDED
WEDNESDAY NIGHT AND THURSDAY MORNING.

SIGNIFICANT SNOW AND AVALANCHE CONDITIONS ARE ALSO EXPECTED IN OTHER
AREAS BUT THAT ARE SLIGHTLY LESS THAN WARNING CRITERIA. AVALANCHES
ARE ALSO LIKELY IN THESE OTHER AREAS AS WELL.

PLEASE VISIT NWAC.US FOR DETAILS. GKF

&&

.AVIATION...A WARM FRONT WILL LIFT NORTHWARD THROUGH WESTERN
WASHINGTON LATE TONIGHT FOLLOWED BY A COLD FRONT LATE MORNING
THURSDAY. UPPER FLOW WILL TURN SOUTHWESTERLY. WIDESPREAD RAIN WITH
LOW MVFR AND AREAS OF IFR CAN BE EXPECTED WITH THE WARM FRONT. THE
RAIN WILL TURN TO SHOWERS MIDDAY THURSDAY WITH CEILINGS LIFTING TO
MOSTLY VFR. SURFACE WINDS WILL BECOME GUSTY FROM THE SOUTH AND
SOUTHWEST THURSDAY MORNING AS AN ASSOCIATED SURFACE LOW MOVES INTO
VANCOUVER ISLAND.


KSEA...MVFR CEILINGS 2-3K FT OVERNIGHT. RAIN WILL REDUCE VISIBILITY
TO 3SM AT TIMES TONIGHT. SOUTHEAST WIND 7 TO 12 KNOTS...SHIFTING TO
SOUTHERLY AFTER 09Z. WINDS WILL RISE FROM THE S-SW AFTER
12Z...GUSTING TO 20-25 KTS AT TIMES INTO THURSDAY AFTERNOON.

&&

.MARINE...WINDS OVER THE COASTAL WATERS ARE STARTING TO RISE OVER
THE PAST HOUR AS A WARM FRONT EDGES CLOSER. GALE WARNINGS REMAIN IN
EFFECT FOR THE COASTAL WATERS OVERNIGHT AND THURSDAY...WITH SMALL
CRAFT ADVISORIES ALL OTHER WATERS. STRONG PRESSURE RISES WILL FOLLOW
A SURFACE LOW AS IT LIFTS INTO VANCOUVER ISLAND EARLY THURSDAY. THIS
WILL LEAD TO SOME GUSTY SOUTH OR SOUTHWEST WINDS OVER THE INLAND
WATERS MUCH OF THURSDAY. WINDS COULD BRIEFLY APPROACH GALE FORCE IN
PARTS OF PUGET SOUND THURSDAY MORNING.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. 27

&&

.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...GALE WARNING COASTAL WATERS.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)








000
FXUS66 KSEW 232231 AAA
AFDSEW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SEATTLE WA
331 PM PDT WED APR 23 2014

UPDATED HYDROLOGY SECTION AND ADDED AVALANCHE SECTION.

.SYNOPSIS...A WARM FRONT WILL SPREAD RAIN INTO WESTERN WASHINGTON
FROM THE SOUTH TONIGHT. A COLD FRONT WILL MOVE INLAND THURSDAY
MORNING. AN UPPER LEVEL TROUGH DIGGING INTO THE PACIFIC NORTHWEST ON
FRIDAY WILL KEEP SCATTERED SHOWERS IN THE FORECAST. A THIRD FRONTAL
SYSTEM WILL BRING ANOTHER ROUND OF MORE ORGANIZED RAINFALL TO THE
AREA SATURDAY NIGHT INTO SUNDAY MORNING.

&&

.SHORT TERM...RAIN WILL INCREASE ACROSS WESTERN WASHINGTON THIS
EVENING AS A WARM FRONT LIFTS NORTH THROUGH THE REGION. THE LEADING
EDGE OF THE PRECIP SHIELD IS NOW UP TO KING COUNTY...RAIN SHOULD
REACH THE NW INTERIOR BY MIDNIGHT TONIGHT. THE COLD FRONT WILL PUSH
INLAND THURSDAY MORNING FOR MORE SHOWERS AND BREEZY TO WINDY
CONDITIONS. SNOW LEVELS WILL RISE TO AROUND 5000 FT WITH THE WARM
FRONT...THEN DROP BACK DOWN TO AROUND 4000 FT BEHIND THE COLD FRONT
ON THURSDAY.

THE AIR MASS WILL REMAIN COOL AND UNSTABLE ON FRIDAY AS AN UPPER
LEVEL LOW OVER THE NE PAC MOVES INLAND. EXPECT ISOLATED TO SCATTERED
SHOWERS WITH TEMPS IN THE 50S. ISOLATED T-STORMS ARE POSSIBLE FRI
AFTERNOON BUT CONFIDENCE IS LOW. THE UPPER LOW WILL WEAKEN AND EXIT
EAST FRI NIGHT WITH SHOWERS DECREASING ACROSS THE AREA.

LOOK FOR A BREAK IN THE WEATHER ON SATURDAY WITH WEAK RIDGING OVER
WESTERN WASHINGTON. THE TIMING OF THE NEXT FRONT IS A LITTLE SLOWER
IN THE MODELS...WHICH IS NOW SLATED TO MOVE INLAND SATURDAY NIGHT
FOR ANOTHER WET PERIOD OF WEATHER. 33

.LONG TERM...MOIST WESTERLY FLOW WILL KEEP A CHANCE OF SHOWERS IN
THE FORECAST ON SUNDAY. MODELS SHOW A WEAK UPPER LEVEL DISTURBANCE
TRACKING THROUGH WESTERN WA FOR SCATTERED ACTIVITY. SHOWERS WILL
DECREASE SUN NIGHT AS A RIDGE START TO BUILD OVER THE PAC NW.

A WEAK WARM FRONT MAY CLIP WESTERN WASHINGTON ON MONDAY FOR A CHANCE
OF RAIN. THE MODELS THEN STRENGTHEN THE RIDGE OVER THE PAC NW TUE
AND WED FOR WARMER AND DRIER WEATHER. THE FORECAST LEANS TOWARD THE
ECMWF SOLUTION WHICH SHOWS AN H5 580 RIDGE OVER WA. THE LOW LEVEL
FLOW IS ALSO TURNING OFFSHORE AND WE SHOULD SEE HIGHS IN THE UPPER
60S TO 70S IF THIS PANS OUT. 33

&&

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

THE EXCEPTION REMAINS 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 WAS
AT 4.6 FT...OR 2840 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.4 FT AT 1850 CFS. THE POOL EAST OF THE SLIDE WAS
282.3 FT THIS AFTERNOON.

A WARM FRONT WILL SPREAD RAIN INTO THE AREA TONIGHT...FOLLOWED BY A
COLD FRONT THURSDAY MORNING. THIS SYSTEM WILL BRING AROUND 1.00 INCH
OF RAINFALL TO THE AREA THROUGH THURSDAY AFTERNOON. THIS IS EXPECTED
TO PRODUCE RISES ON THE STILLAGUAMISH RIVER BEGINNING THIS EVENING
THROUGH THURSDAY. THE LATEST HYDROGRAPH SHOWS THE STILLAGUAMISH NEAR
ARLINGTON CRESTING LATE THURSDAY MORNING AROUND 5 FEET.

&&

.AVALANCHE...FURTHER HEAVY SNOW AND THEN POTENTIAL RAIN SHOULD BE
SEEN IN THE MT RAINIER TO MT HOOD AREA WEDNESDAY NIGHT AND THURSDAY
MORNING. THIS IS VERY LIKELY TO CAUSE WET LOOSE...STORM SLAB AND
WIND SLAB AVALANCHE CONDITIONS IN THIS AREA. AN AVALANCHE WARNING
WILL BE ISSUED FOR THE MT RAINIER TO MT HOOD AREA FOR WEDNESDAY
NIGHT AND THURSDAY MORNING. BACK COUNTRY TRAVEL IN AVALANCHE TERRAIN
IS THIS AREA IS NOT RECOMMENDED WEDNESDAY NIGHT AND THURSDAY
MORNING.

SIGNIFICANT SNOW AND AVALANCHE CONDITIONS ARE ALSO EXPECTED IN OTHER
AREAS BUT THAT ARE SLIGHTLY LESS THAN WARNING CRITERIA. AVALANCHES
ARE ALSO LIKELY IN THESE OTHER AREAS AS WELL.

PLEASE VISIT NWAC.US FOR DETAILS. GKF

&&

.AVIATION...A WARM FRONT WILL MOVE SOUTH TO NORTH THROUGH WASHINGTON
TONIGHT. UPPER FLOW WILL TURN SOUTHWESTERLY. WIDESPREAD RAIN WILL
SPREAD NORTH THIS AFTERNOON AND TONIGHT AS THE WARM FRONT MOVES IN.
AT THE SURFACE A LOW PRES CENTER WILL APPROACH THE COAST TONIGHT
THEN MOVE NORTHEAST INTO VANCOUVER ISLAND TONIGHT...GIVING MODERATE
TO STRONG SOUTHEAST WINDS.

CLOUDS WILL CONTINUE TO INCREASE AND SPREAD NORTH. CEILINGS WILL
LOWER THIS AFTERNOON TO MVFR AS RAIN MOVES IN FROM THE SOUTH. MVFR
CEILINGS ARE LIKELY ALL NIGHT INTO THURSDAY MORNING.

KSEA...MVFR CEILINGS 2-3K FT. RAIN WILL REDUCE VISIBILITY TO 3SM AT
TIMES TONIGHT. SOUTHERLY WIND 10-15 KT. CHB

&&

.MARINE...WARM FRONTAL RAIN BAND IS MOVING SLOWLY NORTH. WINDS HAVE
BEEN 15-20 KT OVER INLAND AREAS...MORE IN A FEW SPOTS...SO HAVE
ISSUED SMALL CRAFT ADVISORIES FOR ALL INLAND WATERS TONIGHT THROUGH
THURSDAY. MODELS HAD SOME LOW END GALE WINDS ON THE COAST SO HAVE
ISSUED A GALE WARNING THERE. GENERALLY IT WILL BE A GUSTY PERIOD
TONIGHT AND THURSDAY.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. YET
ANOTHER SYSTEM ARRIVES AROUND TUESDAY. CHB

&&

.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...GALE WARNING COAST.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)










000
FXUS66 KSEW 232207
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
307 PM PDT WED APR 23 2014

.SYNOPSIS...A WARM FRONT WILL SPREAD RAIN INTO WESTERN WASHINGTON
FROM THE SOUTH TONIGHT. A COLD FRONT WILL MOVE INLAND THURSDAY
MORNING. AN UPPER LEVEL TROUGH DIGGING INTO THE PACIFIC NORTHWEST ON
FRIDAY WILL KEEP SCATTERED SHOWERS IN THE FORECAST. A THIRD FRONTAL
SYSTEM WILL BRING ANOTHER ROUND OF MORE ORGANIZED RAINFALL TO THE
AREA SATURDAY AFTERNOON INTO SUNDAY MORNING.

&&

.SHORT TERM...RAIN WILL INCREASE ACROSS WESTERN WASHINGTON THIS
EVENING AS A WARM FRONT LIFTS NORTH THROUGH THE REGION. THE LEADING
EDGE OF THE PRECIP SHIELD IS NOW UP TO KING COUNTY...RAIN SHOULD
REACH THE NW INTERIOR BY MIDNIGHT TONIGHT. THE COLD FRONT WILL PUSH
INLAND THURSDAY MORNING FOR MORE SHOWERS AND BREEZY TO WINDY
CONDITIONS. SNOW LEVELS WILL RISE TO AROUND 5000 FT WITH THE WARM
FRONT...THEN DROP BACK DOWN TO AROUND 4000 FT BEHIND THE COLD FRONT
ON THURSDAY.

THE AIR MASS WILL REMAIN COOL AND UNSTABLE ON FRIDAY AS AN UPPER
LEVEL LOW OVER THE NE PAC MOVES INLAND. EXPECT ISOLATED TO SCATTERED
SHOWERS WITH TEMPS IN THE 50S. ISOLATED T-STORMS ARE POSSIBLE FRI
AFTERNOON BUT CONFIDENCE IS LOW. THE UPPER LOW WILL WEAKEN AND EXIT
EAST FRI NIGHT WITH SHOWERS DECREASING ACROSS THE AREA.

LOOK FOR A BREAK IN THE WEATHER ON SATURDAY WITH WEAK RIDGING OVER
WESTERN WASHINGTON. THE TIMING OF THE NEXT FRONT IS A LITTLE SLOWER
IN THE MODELS...WHICH IS NOW SLATED TO MOVE INLAND SATURDAY NIGHT
FOR ANOTHER WET PERIOD OF WEATHER. 33

.LONG TERM...MOIST WESTERLY FLOW WILL KEEP A CHANCE OF SHOWERS IN
THE FORECAST ON SUNDAY. MODELS SHOW A WEAK UPPER LEVEL DISTURBANCE
TRACKING THROUGH WESTERN WA FOR SCATTERED ACTIVITY. SHOWERS WILL
DECREASE SUN NIGHT AS A RIDGE START TO BUILD OVER THE PAC NW.

A WEAK WARM FRONT MAY CLIP WESTERN WASHINGTON ON MONDAY FOR A CHANCE
OF RAIN. THE MODELS THEN STRENGTHEN THE RIDGE OVER THE PAC NW TUE
AND WED FOR WARMER AND DRIER WEATHER. THE FORECAST LEANS TOWARD THE
ECMWF SOLUTION WHICH SHOWS AN H5 580 RIDGE OVER WA. THE LOW LEVEL
FLOW IS ALSO TURNING OFFSHORE AND WE SHOULD SEE HIGHS IN THE UPPER
60S TO 70S IF THIS PANS OUT. 33

&&

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

THE EXCEPTION REMAINS 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 9 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.7 FT...OR 2980 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.2 FT AT 1684 CFS. THE POOL EAST OF THE SLIDE WAS
282.5 FT THIS MORNING.

A WARM FRONT WILL SPREAD RAIN INTO THE AREA TONIGHT...FOLLOWED BY A
COLD FRONT THURSDAY MORNING. THIS SYSTEM WILL BRING AROUND 1.00 INCH
OF RAINFALL TO THE AREA THROUGH THURSDAY AFTERNOON. THIS IS EXPECTED
TO PRODUCE RISES ON THE STILLAGUAMISH RIVER BEGINNING THIS EVENING
THROUGH THURSDAY. THE LATEST HYDROGRAPH SHOWS THE STILLAGUAMISH NEAR
ARLINGTON CRESTING THURSDAY MORNING OR AFTERNOON AROUND 5 FEET.

&&

.AVIATION...A WARM FRONT WILL MOVE SOUTH TO NORTH THROUGH WASHINGTON
TONIGHT. UPPER FLOW WILL TURN SOUTHWESTERLY. WIDESPREAD RAIN WILL
SPREAD NORTH THIS AFTERNOON AND TONIGHT AS THE WARM FRONT MOVES IN.
AT THE SURFACE A LOW PRES CENTER WILL APPROACH THE COAST TONIGHT
THEN MOVE NORTHEAST INTO VANCOUVER ISLAND TONIGHT...GIVING MODERATE
TO STRONG SOUTHEAST WINDS.

CLOUDS WILL CONTINUE TO INCREASE AND SPREAD NORTH. CEILINGS WILL
LOWER THIS AFTERNOON TO MVFR AS RAIN MOVES IN FROM THE SOUTH. MVFR
CEILINGS ARE LIKELY ALL NIGHT INTO THURSDAY MORNING.

KSEA...MVFR CEILINGS 2-3K FT. RAIN WILL REDUCE VISIBILITY TO 3SM AT
TIMES TONIGHT. SOUTHERLY WIND 10-15 KT. CHB

&&

.MARINE...WARM FRONTAL RAIN BAND IS MOVING SLOWLY NORTH. WINDS HAVE
BEEN 15-20 KT OVER INLAND AREAS...MORE IN A FEW SPOTS...SO HAVE
ISSUED SMALL CRAFT ADVISORIES FOR ALL INLAND WATERS TONIGHT THROUGH
THURSDAY. MODELS HAD SOME LOW END GALE WINDS ON THE COAST SO HAVE
ISSUED A GALE WARNING THERE. GENERALLY IT WILL BE A GUSTY PERIOD
TONIGHT AND THURSDAY.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA SATURDAY NIGHT. YET
ANOTHER SYSTEM ARRIVES AROUND TUESDAY. CHB

&&

.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...GALE WARNING COAST.
     SMALL CRAFT ADVISORY ALL OTHER WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

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000
FXUS66 KSEW 231628
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
930 AM PDT WED APR 23 2014

.SYNOPSIS...A WARM FRONT WILL SPREAD RAIN INTO WESTERN WASHINGTON
FROM THE SOUTH THIS AFTERNOON AND TONIGHT. A COLD FRONT WILL MOVE
INLAND THURSDAY MORNING. AN UPPER LEVEL TROUGH DIGGING INTO THE
PACIFIC NORTHWEST ON FRIDAY WILL KEEP SCATTERED SHOWERS IN THE
FORECAST. A THIRD FRONTAL SYSTEM WILL BRING ANOTHER ROUND OF MORE
ORGANIZED RAINFALL TO THE AREA SATURDAY AFTERNOON INTO SUNDAY
MORNING.

&&

.SHORT TERM...A WEAK UPPER LEVEL DISTURBANCE IS PRODUCING ISOLATED
TO SCATTERED SHOWERS ACROSS WESTERN WA THIS MORNING. RAIN WILL THEN
INCREASE THIS AFTERNOON AND EVENING AS A WARM FRONT LIFTS NORTH
INTO THE REGION. MODELS SHOW RAIN SPREADING FROM SOUTH TO NORTH
THROUGH THIS EVENING. THE COLD FRONT WILL THEN PUSH INLAND THURSDAY
MORNING FOR MORE SHOWERS AND BREEZY TO WINDY CONDITIONS. SNOW LEVELS
WILL RAISE TO AROUND 5000 FT WITH THE WARM FRONT TODAY...THEN DROP
BACK DOWN TO AROUND 4000 FT BEHIND THE COLD FRONT ON THURSDAY.

THE AIR MASS WILL REMAIN COOL AND UNSTABLE ON FRIDAY AS AN UPPER
LEVEL LOW OVER THE NE PAC MOVES INLAND. EXPECT ISOLATED TO SCATTERED
SHOWERS AGAIN WITH TEMPS IN THE 50S. 33

.LONG TERM...PREVIOUS DISCUSSION...THE ACTIVE WEATHER PATTERN WILL
CONTINUE INTO EARLY NEXT WEEK. THE DIGGING UPPER LEVEL OVER THE WEST
COAST WILL KEEP SHOWERS ACROSS WESTERN WASHINGTON ON SATURDAY. A
FRONTAL SYSTEM WILL MOVE INLAND SATURDAY EVENING BRINGING ANOTHER
ROUND OF ORGANIZED RAINFALL. ONSHORE FLOW AND ZONAL FLOW ALOFT ON
SUNDAY WILL KEEP SHOWERS MAINLY OVER THE COAST AND THE MOUNTAINS.
ANOTHER FRONTAL SYSTEM WILL AFFECT THE REGION MON OR MON NIGHT WITH
MEDIUM RANGE MODELS HINTING AT AN UPPER LEVEL RIDGE BUILDING OVER
THE REGION ON TUE FOR DRIER AND WARMER WEATHER.

&&

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

THE EXCEPTION REMAINS 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 9 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.7 FT...OR 2980 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.2 FT AT 1684 CFS. THE POOL EAST OF THE SLIDE WAS
282.5 FT THIS MORNING.

A WARM FRONT WILL SPREAD RAIN INTO THE AREA TONIGHT...FOLLOWED BY A
COLD FRONT THURSDAY MORNING. THIS SYSTEM WILL BRING AROUND 1.00 INCH
OF RAINFALL TO THE AREA THROUGH THURSDAY AFTERNOON. THIS IS EXPECTED
TO PRODUCE RISES ON THE STILLAGUAMISH RIVER BEGINNING THIS EVENING
THROUGH THURSDAY. THE LATEST HYDROGRAPH SHOWS THE STILLAGUAMISH NEAR
ARLINGTON CRESTING THURSDAY MORNING OR AFTERNOON AROUND 5 FEET.

&&

.AVIATION...A WEAK UPPER RIDGE WILL GIVE MODERATE WESTERLY FLOW
ALOFT OVER WESTERN WASHINGTON TODAY. UPPER FLOW WILL TURN MORE
SOUTHWESTERLY TONIGHT AS A WEATHER SYSTEM MOVES THROUGH THE AREA.
SCATTERED SHOWERS TODAY WILL GIVE WAY TO MORE WIDESPREAD RAIN THIS
AFTERNOON AND TONIGHT AS A WARM FRONT MOVES SOUTH TO NORTH. AT THE
SURFACE A LOW PRES CENTER WILL APPROACH THE COAST TODAY THEN MOVE
NORTHEAST INTO VANCOUVER ISLAND TONIGHT...GIVING MODERATE TO STRONG
SOUTHEAST WINDS.

GENERALLY VFR CEILINGS OR NO CEILINGS...EXCEPT OCCASIONAL MVFR IN
SHOWERS. CLOUDS WILL INCREASE AND CEILINGS WILL LOWER THIS AFTERNOON
AS RAIN MOVES IN FROM THE SOUTH. MVFR CEILINGS ARE LIKELY ALL NIGHT
INTO THURSDAY MORNING.

KSEA...VFR TODAY WITH A CHANCE OF TRANSIENT MVFR IN SHOWERS. MVFR
CEILINGS 2-3K FT AFTER 02Z OR SO. RAIN WILL REDUCE VISIBILITY TO 3SM
AT TIMES TONIGHT. SOUTHERLY WIND 10-15 KT. CHB

&&

.MARINE...AN APPROACHING FRONT AND MODERATELY UNSTABLE CONDITIONS
ARE KEEPING SMALL CRAFT ADVISORY STRENGTH WINDS GOING ON THE COAST
AND IN PUGET SOUND. ADVISORIES ARE IN EFFECT FOR THESE AREAS TODAY.

GRADIENTS INCREASE THIS AFTERNOON AND TONIGHT AS A WARM FRONT MOVES
OVER THE AREA FROM THE SOUTH. THIS WILL BRING MORE WIDESPREAD SMALL
CRAFT ADVISORY WINDS. WINDS COULD TOUCH GALE ON THE COAST. A GALE
WATCH IS IN EFFECT FOR THE COAST AND WEST ENTRANCE TONIGHT. WILL
DECIDE ABOUT THE WATCH AND OTHER ADVISORIES WITH THE AFTERNOON
FORECAST.

AFTER A LULL IN THE ACTION FRIDAY...ANOTHER FRONT WILL SPREAD SMALL
CRAFT ADVISORY STRENGTH WINDS OVER THE AREA ON SATURDAY. CHB

&&

.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 COAST...WEST ENTRANCE...AND PUGET SOUND.
     GALE WATCH COAST AND WEST ENTRANCE TONIGHT.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

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000
FXUS66 KSEW 231100
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
400 AM PDT WED APR 23 2014

.SYNOPSIS...SHOWERS WILL PERSIST THIS MORNING BEFORE A WARM FRONT
BEGINS TO SPREAD RAIN INTO WESTERN WASHINGTON FROM THE SOUTH THIS
AFTERNOON AND TONIGHT. A COLD FRONT WILL MOVE INLAND THURSDAY
MORNING. AN UPPER LEVEL TROUGH DIGGING INTO THE PACIFIC NORTHWEST ON
FRIDAY WILL KEEP SCATTERED SHOWERS IN THE FORECAST. A THIRD FRONTAL
SYSTEM WILL BRING ANOTHER ROUND OF MORE ORGANIZED RAINFALL TO THE
AREA SATURDAY AFTERNOON INTO SUNDAY MORNING.

&&

.SHORT TERM...SHOWERS ASSOCIATED WITH THE UPPER LEVEL SHORT WAVE
TROUGH THAT HAS BEEN WORKING THROUGH THE PACIFIC NORTHWEST OVERNIGHT
HAVE TAPERED OFF SOMEWHAT OVER THE LAST FEW HOURS. EXPECT THE
SHOWERS TO CONTINUE TO DECREASE AS THE UPPER LEVEL TROUGH LIFTS INTO
BRITISH COLUMBIA THIS MORNING. THE BREAK WILL BE SHORTLIVED AS RAIN
WILL INCREASE FROM THE SOUTHWEST DURING THE AFTERNOON AS A WARM
FRONT MOVES INTO THE AREA. THE WARM FRONT WILL BRING MORE ORGANIZED
RAINFALL TO THE AREA...FOLLOWED BY THE COLD FRONT THURSDAY MORNING.
RAIN WILL TRANSITION TO SHOWERS THURSDAY AFTERNOON WITH MOIST AND
SOMEWHAT UNSTABLE SOUTHWEST FLOW ALOFT BEHIND THE FRONT. EXPECT 1 TO
2 INCHES OF RAINFALL WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
OVER THE OLYMPICS AND THE CENTRAL WASHINGTON CASCADES NEAR MOUNT
RAINIER. THE COAST WILL SEE 0.5 TO 0.75 INCHES AND THE INTERIOR UP
TO 0.5 INCHES OVER THE SAME PERIOD. DECENT SOUTHERLY SURFACE
GRADIENTS BEHIND THE FRONT WILL PRODUCE BREEZY WINDS.

AN UPPER TROUGH WILL DIG INTO THE PACIFIC NORTHWEST ON FRIDAY
KEEPING A CHANCE OF SHOWERS OVER THE REGION. THE GOOD NEWS IS
SHOWERS WILL BE SPOTTY AND NOT ORGANIZED WITH A DECENT AMOUNT OF
SUNSHINE IN BETWEEN SHOWERS.

.LONG TERM...THE ACTIVE WEATHER PATTERN WILL CONTINUE INTO EARLY
NEXT WEEK. THE DIGGING UPPER LEVEL OVER THE WEST COAST WILL KEEP
SHOWERS ACROSS WESTERN WASHINGTON ON SATURDAY. A FRONTAL SYSTEM WILL
MOVE INLAND SATURDAY EVENING BRINGING ANOTHER ROUND OF ORGANIZED
RAINFALL. ONSHORE FLOW AND ZONAL FLOW ALOFT ON SUNDAY WILL KEEP
SHOWERS MAINLY OVER THE COAST AND THE MOUNTAINS. ANOTHER FRONTAL
SYSTEM WILL AFFECT THE REGION MON OR MON NIGHT WITH MEDIUM RANGE
MODELS HINTING AT AN UPPER LEVEL RIDGE BUILDING OVER THE REGION ON
TUE FOR DRIER AND WARMER WEATHER.

&&

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

THE EXCEPTION REMAINS 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 315 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.65 FT...OR 2889 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.4 FT AT 1841 CFS. THE POOL EAST OF THE SLIDE WAS
282.5 FT AT 315 AM THIS MORNING.

A WARM FRONT WILL SPREAD RAIN INTO THE AREA TONIGHT...FOLLOWED BY A
COLD FRONT THURSDAY MORNING. THIS SYSTEM WILL BRING AROUND 1.00 INCH
OF RAINFALL TO THE AREA THROUGH THURSDAY AFTERNOON. THIS IS EXPECTED
TO PRODUCE RISES ON THE STILLAGUAMISH RIVER BEGINNING WEDNESDAY
EVENING THROUGH THURSDAY...CRESTING THURSDAY EVENING AROUND 10 PM AT
JUST OVER 5 FEET.

&&

.AVIATION...A TROUGH WILL MOVE E OF WRN WA TODAY WITH A BREAK
BETWEEN WEATHER SYSTEMS. ANOTHER STRONGER LOW PRESSURE SYSTEM WILL
AFFECT THE REGION TONIGHT INTO THURSDAY. MODERATE SW FLOW
ALOFT...BECOMING STRONG TONIGHT. MOIST AND SOMEWHAT UNSTABLE
BECOMING STABLE TONIGHT. DECREASING SHOWERS THIS MORNING...THEN
INCREASING RAIN LATE THIS AFTERNOON AND EVENING. A MIX OF VFR AND
2-3K FT MVFR CEILINGS THIS MORNING...THEN VFR ABOVE 4K FT. WARM
FRONTAL RAIN TONIGHT SHOULD PRODUCE WIDESPREAD MVFR CIGS.

KSEA...VARIABLE CIGS BETWEEN MVFR AND VFR DUE TO SHOWERS THROUGH
16Z...THEN MOSTLY VFR. MVFR CIGS AND VIS SHOULD DOMINATE TONIGHT
WITH STEADY RAIN. S WIND 4-8 KT...BECOMING SW 10-15 W/ GUSTS TO 25
KT LATER TONIGHT.

&&

.MARINE...THERE WILL BE A LULL IN WINDS TODAY AHEAD OF THE NEXT
STRONGER LOW PRESSURE SYSTEM. SLY WINDS OVER THE COASTAL WATERS WILL
VARY IN STRENGTH THROUGH THE DAY TOPPING 20 KT AT TIMES W/ SWELL
AROUND 10 FT. THEREFORE...A SMALL CRAFT ADVISORY REMAIN UP FOR THE
COAST. WINDS ELSEWHERE BELOW 20 KT TODAY. A 990 MB LOW WILL TRACK NE
OUTSIDE THE OUTER COASTAL WATERS INTO VANCOUVER ISLAND TONIGHT. THE
TRACK IS CLOSE ENOUGH SO THAT HIGH END SMALL CRAFT WINDS OVER THE
COAST AND W ENTRANCE ARE LIKELY...POSSIBLY REACHING GALE FORCE AT
TIMES FROM THIS EVENING THROUGH THURSDAY MORNING. A GALE WATCH
IS IN EFFECT TONIGHT AND THURSDAY MORNING FOR THE COAST/W ENTRANCE
BUT KEPT WINDS TO 30 KT IN THE FORECAST FOR NOW GIVEN THE
UNCERTAINTY. SMALL CRAFT WINDS SHOULD DEVELOP OVER THE REMAINING
WATERS TONIGHT INTO THURSDAY...THEN EASE.

A LULL IN WINDS EXPECTED FRIDAY...THEN MORE WIDESPREAD SMALL CRAFT
WINDS POSSIBLE WITH THE NEXT SYSTEM ON SATURDAY.

&&

.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 COAST THROUGH THIS AFTERNOON.
     GALE WATCH COAST AND WEST ENTRANCE TO THE STRAIT OF JUAN DE
     FUCA FROM 5 PM PDT THROUGH THURSDAY MORNING.

&&

$$

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000
FXUS66 KSEW 230401
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT TUE APR 22 2014

.SYNOPSIS...A COLD FRONT WILL BRING SHOWERS TONIGHT. A WARM FRONT
WILL SPREAD RAIN INTO WESTERN WASHINGTON WEDNESDAY AFTERNOON THROUGH
WEDNESDAY NIGHT. A SECOND COLD FRONT WILL THEN SHIFT INLAND THURSDAY
MORNING. AN UPPER LEVEL TROUGH WILL CROSS THE REGION ON FRIDAY FOR
SCATTERED SHOWERS. A THIRD FRONTAL SYSTEM WILL BRING RAIN TO THE
AREA THIS WEEKEND.

&&

.SHORT TERM...SHOWERS WILL BE NUMEROUS THIS EVENING AS AN UPPER
SHORT WAVE MOVES ONSHORE. THEY WILL PROBABLY TAPER A BIT AFTER
MIDNIGHT AS THE UPPER LEVEL DISTURBANCE MOVES EAST OF THE AREA.

AFTER A BIT OF A BREAK FOR THE FIRST PART OF WEDNESDAY...RAIN WILL
INCREASE FROM THE SOUTHWEST LATE IN THE DAY AS A WARM FRONT MOVES
INTO THE AREA. THE WARM FRONT/COLD FRONT COMBO WILL MOVE ONSHORE
WEDNESDAY NIGHT/THURSDAY MORNING FOR A PERIOD OF RAIN ALL AREAS.

THURSDAY WILL SEE SHOWERS BEHIND THE FRONT WITH MOIST AND SOMEWHAT
UNSTABLE SOUTHWEST FLOW ALOFT. SOUTHERLY SURFACE GRADIENTS WILL BE
PRETTY STRONG BEHIND THE FRONT FOR SOME BREEZY WINDS.

AN UPPER TROUGH WILL SETTLE OVER THE PACIFIC NORTHWEST ON FRIDAY FOR
A CONTINUED CHANCE OF SHOWERS. MOST OF THE FLOW ALOFT WILL BE FAR TO
THE SOUTH AND SHOWERS WILL BE SPOTTY AND NOT TOO ORGANIZED. THERE
SHOULD BE A DECENT AMOUNT OF SUNSHINE IN BETWEEN SHOWERS. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...AN UPPER LEVEL TROUGH OVER THE
PAC NW WILL LEAD TO A FEW MORE SHOWERS ACROSS WESTERN WA ON
SATURDAY. OUR NEXT FRONTAL SYSTEM WILL THEN MOVE INLAND SATURDAY
NIGHT FOR A WETTER PERIOD OF WEATHER. ONSHORE FLOW WILL CONTINUE ON
SUNDAY WITH ZONAL FLOW ALOFT - SHOWERS WILL MAINLY AFFECT THE COAST
AND IN THE MOUNTAINS.

ANOTHER PAC FRONTAL SYSTEM WILL CROSS THE REGION MON OR MON NIGHT.
AN UPPER LEVEL RIDGE WILL BUILD OVER THE PAC NW ON TUE FOR DRIER AND
WARMER WEATHER. 33

&&

.HYDROLOGY...RIVER FLOODING REMAINS 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.

A FRONT WEDNESDAY NIGHT THROUGH THURSDAY COULD GIVE 1.00 INCH OF
RAIN. IF THIS OCCURS...THE NORTH FORK OF THE STILLAGUAMISH RIVER IN
THE SLIDE AREA WILL SEE MORE SIGNIFICANT RISES THAN WHAT ARE
CURRENTLY INDICATED IN THE RIVER FORECASTS.

AT 8 PM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS AT
4.7 FT...OR 2880 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER NEAR
OSO WAS AT 216.7 FT AT 2050 CFS. THE POOL EAST OF THE SLIDE WAS
282.7 FT AT 6 PM THIS EVENING.

&&

.AVIATION...AN UPPER LEVEL AND SURFACE TROUGH WILL MOVE THROUGH WRN
WA TONIGHT. THERE WILL BE A BREAK BETWEEN SYSTEMS WEDNESDAY
MORNING...THEN ANOTHER TROUGH ARRIVES WEDNESDAY AFTERNOON AND
WEDNESDAY NIGHT. MODERATE SW FLOW ALOFT. MOIST AND SOMEWHAT UNSTABLE
THROUGH WEDNESDAY. SHOWERS...DECREASING LATE TONIGHT...INCREASING
WEDNESDAY AFTERNOON. A MIX OF VFR AND 2-4K FT MVFR CEILINGS.
WEDNESDAY SHOULD HAVE MOSTLY VFR CONDITIONS.

KSEA...CIGS VARIABLE BUT GENERALLY VFR...EXCEPT 2-3K FT CIGS WITH
SHOWERS THROUGH 12. GUSTY SOUTHWEST WINDS 8-12 KT...EASING TO 4-8 KT
AFTER MIDNIGHT.

&&

.MARINE...A SURFACE TROUGH WILL SLOWLY MOVE THROUGH THE WATERS
TONIGHT. HAVE EXTENDED THE SMALL CRAFT ADVISORY THROUGH 5 AM PDT AND
INCLUDES ALL WATERS EXCEPT THE CENTRAL STRAIT. WINDS SHOULD EASE
WEDNESDAY MORNING...THEN INCREASE LATE WEDNESDAY AFTERNOON EVENING
AHEAD OF THE NEXT SYSTEM ARRIVING THURSDAY. THIS ONE LOOKS STRONGER
SO SMALL CRAFT ADVISORY STRENGTH WINDS ARE LIKELY OVER MOST WATERS.
ANOTHER FRONT WILL ARRIVE ABOUT SATURDAY. 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 EXCEPT CENTRAL STRAIT.

&&

$$

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000
FXUS66 KSEW 222229
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 PM PDT TUE APR 22 2014

.SYNOPSIS...ANOTHER COLD FRONT AND UPPER LEVEL TROUGH WILL BRING
SHOWERS TO THE REGION TONIGHT. A WARM FRONT WILL SPREAD RAIN NORTH
INTO WESTERN WASHINGTON WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT.
THE COLD FRONT WILL THEN SHIFT INLAND THURSDAY MORNING. AN UPPER
LEVEL TROUGH WILL CROSS THE REGION ON FRIDAY FOR SCATTERED SHOWERS.
ANOTHER FRONTAL SYSTEM WILL BRING MORE RAIN TO THE AREA THIS
WEEKEND.

&&

.SHORT TERM...THE REGION CONTINUES TO SEE ISOLATED TO SCATTERED
SHOWERS THIS AFTERNOON...BUT SHOWERS WILL INCREASE IN COVERAGE
TONIGHT AS ANOTHER COLD FRONT AND UPPER LEVEL TROUGH MOVE INLAND.
THE FRONT IS OVER THE COASTAL WATERS RIGHT NOW WITH SHOWERS REACHING
THE COAST EARLY THIS EVENING...THEN SPREADING INTO THE INTERIOR BY
MIDNIGHT. WE MAY SEE A BRIEF BREAK IN THE WEATHER LATE WED MORNING
AND AFTERNOON...THEN MORE RAIN TOWARD THE EVENING AS A WARM FRONT
MOVES IN. MODELS SHOW RAIN SPREADING FROM SOUTH TO NORTH. THE COLD
FRONT WILL MOVE INLAND THURSDAY MORNING FOR BREEZY CONDITIONS AND
MORE SHOWERS. A PUGET SOUND CONVERGENCE ZONE WILL LIKELY FORM THU
AFTERNOON/EVENING AS LOW LEVEL ONSHORE FLOW INCREASES. EXPECT A FEW
MORE SHOWERS ON FRIDAY AS ANOTHER WEAK UPPER LEVEL TROUGH CROSSES
WESTERN WA. 33

.LONG TERM...AN UPPER LEVEL TROUGH OVER THE PAC NW WILL LEAD TO A
FEW MORE SHOWERS ACROSS WESTERN WA ON SATURDAY. OUR NEXT FRONTAL
SYSTEM WILL THEN MOVE INLAND SATURDAY NIGHT FOR A WETTER PERIOD OF
WEATHER. ONSHORE FLOW WILL CONTINUE ON SUNDAY WITH ZONAL FLOW ALOFT
- SHOWERS WILL MAINLY AFFECT THE COAST AND IN THE MOUNTAINS.

ANOTHER PAC FRONTAL SYSTEM WILL CROSS THE REGION MON OR MON NIGHT.
AN UPPER LEVEL RIDGE WILL BUILD OVER THE PAC NW ON TUE FOR DRIER AND
WARMER WEATHER. 33

&&

.HYDROLOGY...RIVER FLOODING REMAINS 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.

A FRONT WEDNESDAY NIGHT THROUGH THURSDAY COULD GIVE 1.00 INCH OF
RAIN. IF THIS OCCURS...THE NORTH FORK OF THE STILLAGUAMISH RIVER IN
THE SLIDE AREA WILL SEE MORE SIGNIFICANT RISES THAN WHAT ARE
CURRENTLY INDICATED IN THE RIVER FORECASTS.

AT 3 PM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS AT
4.8 FT...OR 3130 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER NEAR
OSO WAS AT 216.7 FT AT 2120 CFS. THE SLIDE POOL EAST OF THE SLIDE
WAS AT 282.9 FT 1130 AM THIS MORNING.

&&

.AVIATION...AN UPPER LEVEL TROUGH WILL MOVE SLOWLY THROUGH THE
PACIFIC NORTHWEST TONIGHT WITH LIGHT TO MODERATE WESTERLY FLOW
ALOFT. THE AIR MASS IS WEAKLY UNSTABLE AND MOIST WITH SCATTERED
SHOWERS. SATELLITE IMAGERY SHOWS A FRONT LIKE FEATURE JUST REACHING
THE COAST WITH WEAK CONVECTION CELLS OVER THE LAND.

THE FORECAST IS FOR SHOWERS TO CONTINUE INTO THE EVENING...THEN MORE
STEADY RAIN WILL OCCUR AS THE FRONT MOVES BY. RAIN WILL TAPER TO
SCATTERED SHOWERS LATE TONIGHT. GENERALLY VFR CEILINGS WILL BECOME A
MIX OF VFR AND 2-4K FT MVFR CEILINGS AS THE FRONT MOVES THROUGH
BEGINNING AROUND 03Z. WEDNESDAY SHOULD HAVE MOSTLY VFR CONDITIONS.

KSEA...VFR CONDITIONS WITH SOME HOURS OF 3-4K FT CEILINGS 03Z-09Z.
GUSTY SOUTHWEST WINDS 10-14G20 KT WILL TAPER AFTER 06Z. CHB

&&

.MARINE...SCATTERED CONVECTION COUPLED WITH AN APPROACHING FRONT
BROUGHT SMALL CRAFT ADVISORY SOUTHERLY WINDS TO MOST WATERS THIS
AFTERNOON. ADVISORIES ARE NOW IN EFFECT FOR ALL WATERS EXCEPT THE
CENTRAL STRAIT. IN GENERAL THESE WINDS WILL CONTINUE INTO THE
EVENING WITH THE ADVISORIES SET TO EXPIRE AT 11 PM.

ANOTHER SYSTEM WILL ARRIVE THURSDAY. THIS ONE LOOKS STRONGER SO
SMALL CRAFT ADVISORY STRENGTH WINDS ARE LIKELY OVER MOST WATERS.
ANOTHER FRONT WILL ARRIVE ABOUT SATURDAY. CHB

&&

.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 EXCEPT CENTRAL STRAIT.

&&

$$

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WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)







000
FXUS66 KSEW 221613
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
912 AM PDT TUE APR 22 2014

.SYNOPSIS...AN UPPER TROUGH MOVING THROUGH THE REGION WILL KEEP COOL
AND SHOWERY CONDITIONS OVER WESTERN WASHINGTON TODAY. THIS PATTERN
WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AS A SERIES OF
WEATHER SYSTEMS ARE EXPECTED TO MOVE ACROSS THE AREA. THE STRONGEST
OF THESE SYSTEMS WILL BRING RAIN AND BREEZY CONDITIONS WEDNESDAY
NIGHT AND THURSDAY.

&&

.SHORT TERM...A COLD FRONT PASSED THROUGH WESTERN WA OVERNIGHT WITH
POST-FRONTAL ONSHORE FLOW ACROSS WESTERN WA. SHOWERS ARE MAINLY OVER
KING/SNOHOMISH COUNTIES FROM A PUGET SOUND CONVERGENCE ZONE THIS
MORNING. THE FLOW WILL REMAIN ONSHORE TODAY AND AN UPPER LEVEL
TROUGH WILL MAINTAIN ISOLATED TO SCATTERED SHOWERS ACROSS THE
REGION. TEMPS WILL REMAIN IN THE LOW TO MID 50S.

SHOWERS WILL INCREASE IS COVERAGE TONIGHT AS ANOTHER COLD FRONT
AND UPPER LEVEL TROUGH MOVE INLAND. WE MAY SEE A BRIEF BREAK IN THE
WEATHER LATE WED MORNING AND AFTERNOON...THEN MORE RAIN TOWARD THE
EVENING AS A WARM FRONT MOVES IN /RAIN WILL SPREAD SOUTH TO NORTH/.
WEDNESDAY NIGHT THROUGH THURSDAY MORNING WILL BE ANOTHER WET PERIOD
OF WEATHER AS THE WARM FRONT LIFTS NORTH THROUGH THE AREA...FOLLOWED
BY THE COLD FRONT. 33

.LONG TERM...PREVIOUS DISCUSSION...SHOWERS WILL LINGER THURSDAY
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH SLOWLY LIFTS TO THE
NORTHEAST OVER BRITISH COLUMBIA. A SECOND WELL DEFINED FRONTAL
SYSTEM WILL BEGIN TO AFFECT THE AREA SATURDAY NIGHT THROUGH SUNDAY.
MEDIUM RANGE MODELS DIFFER ON EARLY NEXT WEEK WITH THE ECMWF
CONTINUING TO HINT AT A DRYING TREND AND A CHANGE TO MORE
RIDGING...WHILE THE GFS40 KEEPS SHOWERS AND ZONAL FLOW OVER THE
PACIFIC NORTHWEST.
&&

.HYDROLOGY...RIVER FLOODING REMAINS 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.

RAINFALL FROM LAST NIGHTS FRONTAL SYSTEM AND UPPER LEVEL TROUGH IS
EXPECTED TO PRODUCE RISES OF 0.5 TO 1 FT ON THE NORTH FORK OF THE
STILLAGUAMISH RIVER TODAY BEFORE SLOWLY FALLING TONIGHT INTO
WEDNESDAY WITH LINGERING LIGHT SHOWERS OVER THE AREA. A MORE
SIGNIFICANT FRONT LATE WEDNESDAY NIGHT THROUGH THURSDAY COULD GIVE
1-2 INCHES OF RAIN. IF THIS OCCURS...THE NORTH FORK OF THE
STILLAGUAMISH RIVER IN THE SLIDE AREA WILL SEE MORE SIGNIFICANT
RISES THAN WHAT ARE CURRENTLY INDICATED IN THE RIVER FORECASTS.

AT 9 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.6 FT...OR 2900 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.7 FT AT 2100 CFS.

&&

.AVIATION...AN UPPER LEVEL TROUGH WILL MOVE SLOWLY THROUGH THE
PACIFIC NORTHWEST TODAY AND TONIGHT WITH LIGHT TO MODERATE WESTERLY
FLOW ALOFT. THE AIR MASS IS WEAKLY UNSTABLE AND MOIST WITH SCATTERED
SHOWERS. SATELLITE IMAGERY SHOWS THE REMNANTS OF A FRONT OVER THE
NORTHEAST PORTION OF THE AREA WITH CONSIDERABLE CLEARING ELSEWHERE.

THE FORECAST IS FOR SHOWERS DECREASING THIS MORNING THEN INCREASING
AGAIN LATE THIS AFTERNOON AS A CUMULUS FIELD DEVELOPS OVER CURRENTLY
CLEAR AREAS. CEILINGS ARE NONEXISTENT OR VFR OVER THE MAJORITY OF
THE AREA THIS MORNING EXCEPT FOR SOME 2.5-3.5K FT CEILINGS FROM
PIERCE COUNTY NORTH. MOST TERMINALS WILL BE VFR BY LATE MORNING.

KSEA...DISCUSSION ABOVE APPLIES. VFR CEILINGS AFTER 18Z. LIGHT WIND
BECOMING S 6-10 KT LATER THIS MORNING AND AFTERNOON. CHB

&&

.MARINE...SMALL CRAFT ADVISORY WESTERLY WINDS OF 15 TO 25 KT THROUGH
THE CENTRAL AND EAST STRAIT WILL CONTINUE A FEW MORE HOURS THIS
MORNING. AN APPROACHING FRONT WILL BRING SMALL CRAFT ADVISORY
SOUTHERLY WINDS TO THE COASTAL WATERS BY THIS AFTERNOON. THESE WILL
CONTINUE INTO THE EVENING.

ANOTHER SYSTEM WILL ARRIVE THURSDAY. THIS ONE LOOKS STRONGER WITH
SMALL CRAFT ADVISORY STRENGTH WINDS POSSIBLE OVER MOST WATERS. CHB

&&

.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 COAST AND CENTRAL AND EAST STRAIT.

&&

$$

WWW.WEATHER.GOV/SEATTLE

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000
FXUS66 KSEW 221053
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
350 AM PDT TUE APR 22 2014

.SYNOPSIS...AN UPPER TROUGH MOVING THROUGH THE REGION WILL KEEP COOL
AND SHOWERY CONDITIONS OVER WESTERN WASHINGTON TODAY. THIS PATTERN
WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AS A SERIES OF
WEATHER SYSTEMS ARE EXPECTED TO MOVE ACROSS THE AREA. THE STRONGEST
OF THESE SYSTEMS WILL BRING RAIN AND BREEZY CONDITIONS WEDNESDAY
NIGHT AND THURSDAY.

&&

.SHORT TERM...THE UPPER LEVEL TROUGH THAT HAS BEEN SHIFTING ONSHORE
OVER NIGHT WILL KEEP SHOWERS OVER THE AREA TODAY...WITH THE BEST BET
REMAINING THE CENTRAL SOUND INTO THE CASCADES THROUGH THE MORNING
HOURS WITH THE EXPECTED WEAK PUGET SOUND CONVERGENCE ZONE. SHOWERS
WILL TAPER OFF THROUGH THE AFTERNOON BEFORE THE NEXT UPPER TROUGH
BEGINS TO SPREAD MORE SHOWERS ONTO THE COAST LATE IN THE AFTERNOON
AND OVER THE INTERIOR DURING THE EVENING.

WEDNESDAY MORNING AND EARLY AFTERNOON WILL SEE A BRIEF BREAK IN THE
SHOWERS AS HIGH PRESSURE ALOFT BUILDS OVER THE AREA. WARM FRONTAL
PRECIPITATION WILL BEGIN TO SPREAD NORTH INTO THE SOUTHWESTERN
WASHINGTON LATE IN THE AFTERNOON AS A MORE ORGANIZED FRONTAL SYSTEM
BEGINS TO MOVE INTO THE REGION. THIS SYSTEM WILL BRING BREEZY
CONDITIONS AND POTENTIALLY HEAVY LOCAL RAIN AT TIMES ESPECIALLY OVER
THE COAST...OLYMPIC PENINSULA AND THE CASCADES THROUGH THURSDAY
MORNING.

.LONG TERM...SHOWERS WILL LINGER THURSDAY NIGHT AND FRIDAY AS THE
UPPER LEVEL TROUGH SLOWLY LIFTS TO THE NORTHEAST OVER BRITISH
COLUMBIA. A SECOND WELL DEFINED FRONTAL SYSTEM WILL BEGIN TO AFFECT
THE AREA SATURDAY NIGHT THROUGH SUNDAY. MEDIUM RANGE MODELS DIFFER
ON EARLY NEXT WEEK WITH THE ECMWF CONTINUING TO HINT AT A DRYING
TREND AND A CHANGE TO MORE RIDGING...WHILE THE GFS40 KEEPS SHOWERS
AND ZONAL FLOW OVER THE PACIFIC NORTHWEST.
&&

.HYDROLOGY...RIVER FLOODING REMAINS 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.

RAINFALL FROM LAST NIGHTS FRONTAL SYSTEM AND UPPER LEVEL TROUGH IS
EXPECTED TO PRODUCE RISES OF 0.5 TO 1 FT ON THE NORTH FORK OF THE
STILLAGUAMISH RIVER TODAY BEFORE SLOWLY FALLING TONIGHT INTO
WEDNESDAY WITH LINGERING LIGHT SHOWERS OVER THE AREA. A MORE
SIGNIFICANT FRONT LATE WEDNESDAY NIGHT THROUGH THURSDAY COULD GIVE
1-2 INCHES OF RAIN. IF THIS OCCURS...THE NORTH FORK OF THE
STILLAGUAMISH RIVER IN THE SLIDE AREA WILL SEE MORE SIGNIFICANT
RISES THAN WHAT ARE CURRENTLY INDICATED IN THE RIVER FORECASTS.

AT 330 AM...THE NORTH FORK OF THE STILLAGUAMISH NEAR ARLINGTON WAS
AT 4.4 FT...OR 2587 CFS. THE NORTH FORK OF THE STILLAGUAMISH RIVER
NEAR OSO WAS AT 216.4 FT AT 1803 CFS. THE SLIDE POOL EAST OF THE
SLIDE WAS AT 283 FT AT 630 PM MONDAY EVENING.

&&

.AVIATION...AN UPPER TROUGH OVER THE PAC NW WILL SLOWLY SHIFT EWD
TONIGHT. LIGHT TO MODERATE WLY FLOW ALOFT. WEAKLY UNSTABLE
ATMOSPHERE AND MOIST WITH SHOWERS...DECREASING THIS MORNING...AND
INCREASING AGAIN LATE THIS AFTERNOON. AREAS OF MVFR AND PATCHY IFR
CIGS EARLY THIS MORNING...THEN IMPROVING TO A VFR CEILING DECK BY
18Z.

KSEA...MVFR CIGS 1500-2500 FEET EARLY AND POSSIBLY IFR 500-900 FEET
AT TIMES THROUGH 15Z. VFR CEILINGS AFTER 18Z. LIGHT WIND BECOMING S
6-10 KT LATER THIS MORNING AND AFTERNOON. DTM

&&

.MARINE...SMALL CRAFT ADVISORY WESTERLY WINDS OF 15 TO 25 KT THROUGH
THE CENTRAL/E STRAIT REACHING PORTIONS OF THE SRN N INLAND WATERS
AND N PART OF ADMIRALTY INLET...EASING THIS MORNING. ANOTHER
APPROACHING FRONT WILL BRING RENEWED SMALL CRAFT WINDS TO THE
COASTAL WATERS BY THIS AFTERNOON.

ANOTHER SYSTEM WILL ARRIVE THURSDAY. THIS ONE LOOKS STRONGER WITH
SMALL CRAFT ADVISORY STRENGTH WINDS POSSIBLE OVER MOST WATERS. 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 FOR WIND CENTRAL AND EAST STRAIT...
     ADMIRALTY INLET...AND NORTHERN INLAND WATERS.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COAST.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

WWW.WEATHER.GOV/SEATTLE

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WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML   (ALL LOWERCASE)












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