000
FXUS66 KSEW 191542
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
845 AM PDT WED JUN 19 2013
.SYNOPSIS...AN UPPER LEVEL LOW IS OVER THE PACIFIC NORTHWEST.
SCATTERED SHOWERS WILL INCREASE THROUGH THURSDAY...ESPECIALLY NORTH
OF SEATTLE AND IN THE CASCADES. WEAK HIGH PRESSURE WILL BUILD INTO
THE AREA FRIDAY NIGHT AND SATURDAY. A SERIES OF FRONTS WILL BRING
WET WEATHER AGAIN EARLY NEXT WEEK.
&&
.SHORT TERM...THE FLOW ALOFT HAS BACKED TO MORE EASTERLY AS THE
UPPER LOW CENTER SHIFTS OVER OREGON TODAY. SOME SHOWERS HAVE PUSHED
WWD ACROSS THE CASCADES...MAINLY NORTH OF SEATTLE. AT 9AM THIS
MORNING SKIES ACROSS WESTERN WA RANGE FROM SUNNY ON THE COAST TO
CLOUDY INLAND...BUT SOME CU WILL LIKELY LIFT UP AND FILL IN THE
COASTAL AREAS WITH A CHANCE OF SHOWERS THIS AFTERNOON...AND THE
CLOUDY AREAS INLAND WILL PROBABLY SEE SOME SUNBREAKS THIS AFTERNOON.
THE BEST CHANCE OF SHOWERS WILL PROBABLY REMAIN NORTH AND EAST OF
SEATTLE IN THE MORE SOUTHEAST OR EASTERLY FLOW NORTH OF THE LOW
CENTER...AND THERE IS A GOOD CHANCE THAT THE SHOWERS WILL INCREASE
BY THURSDAY. THERE WILL PROBABLY BE A GOOD SOAKING RAIN IN THE NORTH
CASCADES. THE LOW WILL SHIFT INLAND FRIDAY AND WEAK HIGH PRESSURE
WILL BUILD IN TO THE AREA.
&&
.LONG TERM...SATURDAY LOOKS AND WILL LIKELY BE THE WARMEST DAY OF
THE WEEK WITH HIGHS IN THE 70S MANY AREAS AS A SHORT WAVE UPPER
RIDGE MOVES OVERHEAD. A FRONTAL SYSTEM WILL BE APPROACHING FROM THE
WEST SATURDAY NIGHT AND SUNDAY. MODELS ARE HAVING A HARD TIME
AGREEING ON WHEN THIS SYSTEM WILL MAKE LANDFALL AND THERE HAS BEEN A
FAIR AMOUNT OF RUN TO RUN WAFFLING AS WELL. IF THE GFS IS CORRECT...
MOST OF THE AREA WILL REMAIN DRY AND HIGHS WILL BE SIMILAR TO
SATURDAY. IF THE ECMWF IS CORRECT...IT WILL BE A RAINY AND COOLER
DAY WITH HIGHS IN THE 60S. ANOTHER RELATIVELY WET FRONT WILL MOVE
ONSHORE AROUND MONDAY NIGHT. CONFIDENCE IN THE TIMING AND OTHER
SPECIFICS WITH THIS FRONT IS LOW FOR NOW. SCHNEIDER
&&
.AVIATION...UPPER LEVEL LOW OFF THE SOUTH WASHINGTON COAST IS
FORECAST TO MOVE SE INTO NW OREGON BY THIS AFTERNOON AND ACROSS
NORTHERN OREGON TONIGHT INTO THURSDAY. FLOW ALOFT BECOMING MORE
EASTERLY ACROSS WASHINGTON AS THE LOW MOVES INLAND. AIR MASS
UNSTABLE AND BECOMING MORE MOIST INTO THURSDAY. LOW LEVEL ONSHORE
FLOW TO INCREASE THROUGH THURSDAY.
DOPPLER WEATHER RADAR SHOWS INCREASING SHOWERS MOVING WEST INTO THE
CENTRAL AND NORTHERN PUGET SOUND AREA THIS MORNING. CEILINGS IN THIS
REGION HAVE FALLEN INTO THE MVFR CATEGORY. CEILINGS ELSEWHERE REMAIN
VFR. THERE MAY BE SOME IMPROVEMENT IN CEILINGS IN THE MVFR AREAS AS
THE DAY WEARS ON...BUT LIKELY SEE CEILINGS LOWER ELSEWHERE AS MOVE
CLOUD COVER AND SHOWERS MOVE WEST AROUND THE UPPER LOW.
KSEA...MVFR CEILING LIKELY TO LIFT SOME - 2500-3500 FT - BY 19Z OR
SO BUT ALSO SOME SHOWERS TO MOVE IN FROM THE EAST BY 20Z. SOUTHERLY
WINDS 4 TO 8 KNOTS BECOMING SW 6 TO 10 KNOTS THIS AFTERNOON. BUEHNER
&&
.MARINE...A WEAK 1013 MB LOW JUST OFF WILLAPA BAY IS FORECAST TO
SHIFT INLAND TO EASTERN WASHINGTON BY TONIGHT. HIGHER PRES OVER THE
OFFSHORE WATERS WILL BUILD A BIT WITH INCREASING LOW LEVEL ONSHORE
FLOW INTO WESTERN WASHINGTON TONIGHT AND CONTINUING INTO THURSDAY.
A GALE WARNING IS IN PLACE FOR THE CENTRAL AND EASTERN STRAIT OF
JUAN DE FUCA FOR TONIGHT WITH A SMALL CRAFT ADVISORY IN EFFECT UNTIL
THEN. IN ADDITION A SMALL CRAFT ADVISORY REMAINS FOR THE NORTHERN
INLAND WATERS. WINDS EASING LATER THURSDAY AS SURFACE HIGH PRESSURE
BEGINS TO BUILD INTO THE AREA AND PRESSURES RISE OVER BRITISH
COLUMBIA. HIGH PRESSURE OVER THE WATERS ON FRIDAY. A FRONT WILL
APPROACH THE COASTAL WATERS ON SATURDAY AND MOVE INLAND ON SUNDAY.
BUEHNER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING CENTRAL AND EASTERN STRAIT.
SMALL CRAFT ADVISORY NORTHERN INLAND WATERS.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 191059 CCA
AFDSEW
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SEATTLE WA
400 AM PDT WED JUN 19 2013
.SYNOPSIS...AN UPPER LOW WILL PRODUCE SCATTERED SHOWERS. A TROUGH
ROTATING WESTWARD TO THE NORTH OF THE LOW WILL BRING A PERIOD OF
STEADIER AND HEAVIER RAIN TO MUCH OF THE AREA THURSDAY AND THURSDAY
NIGHT. WEAK HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY NIGHT AND
SATURDAY. A SERIES OF FRONTS WILL BRING WET WEATHER AGAIN EARLY NEXT
WEEK.
&&
.SHORT TERM...AN UPPER LOW JUST OFF THE COAST WILL SLOWLY SHIFT
INLAND OVER OREGON TODAY. MOIST AND UNSTABLE SOUTHERLY FLOW ALOFT
WILL WEAKEN AND BECOME MORE EASTERLY TODAY. THERE WILL BE ISOLATED
TO SCATTERED SHOWERS AGAIN TODAY...MOSTLY DIURNALLY DRIVEN IN THE
AFTERNOON OVER THE CASCADES AND SOUTH PART OF THE FORECAST AREA
CLOSEST TO THE UPPER LOW. THE THUNDERSTORM THREAT LOOKS MINIMAL AT
BEST TODAY WITH LIFTED INDICES THIS AFTERNOON ONLY DOWN TO AROUND
ZERO AND CAPE VALUES BARELY CRACKING 100 J/KG. THERE MIGHT BE AN
ISOLATED STORM OR TWO OVER THE SOUTH INTERIOR OR OVER THE CASCADES
LATER TODAY BUT THE CHANCES ARE NOT HIGH ENOUGH TO MENTION IN THE
FORECAST. HIGHS WILL COOL A FEW DEGREES TODAY AS THE UPPER LOW MOVES
CLOSER. HOWEVER...GUIDANCE HAS HAD A NOTICEABLE COOL BIAS THE LAST
FEW DAYS. THE FORECAST HIGHS FOR TODAY HAVE BEEN BUMPED UP TO
ACCOUNT FOR THIS.
THE UPPER LOW WILL SHIFT OVER EASTERN WASHINGTON ON THURSDAY. A
RATHER WELL DEFINED SHORT WAVE ROTATING AROUND THE TOP OF THE UPPER
LOW WILL SPREAD STEADIER RAIN INTO WESTERN WASHINGTON EARLY
THURSDAY. THE NORTHERN HALF OF THE FORECAST AREA WILL SEE THE BRUNT
OF THE RAIN WITH AMOUNTS RAPIDLY DROPPING OFF TO THE SOUTH. THE
HEAVIEST RAINS ARE EXPECTED TO BE OVER THE NORTHERN CASCADES WHERE
1-2 INCHES ARE A GOOD BET BY LATE THURSDAY WITH LOCALLY HIGHER
AMOUNTS POSSIBLE. WITH ALL THE CLOUDS AND RAIN...HIGHS WILL STRUGGLE
TO CLIMB OUT OF THE LOWER 60S...ESPECIALLY FROM SEATTLE NORTH. ALSO
OF NOTE...ONSHORE GRADIENTS WILL TIGHTEN IN RESPONSE TO FALLING
PRESSURES OVER SOUTHERN BRITISH COLUMBIA AS THE SHORT WAVE ROTATES
THROUGH. THIS WILL GIVE BREEZY SOUTHERLY WINDS TO PARTS OF THE AREA
THURSDAY...SOMEWHAT UNUSUAL FOR LATE JUNE.
SCATTERED SHOWERS WILL BE TAPERING ON FRIDAY AS THE UPPER LOW
WEAKENS AND PULLS AWAY FROM THE AREA. EVEN THOUGH SHOWERS WILL BE
DECREASING...THERE WILL BE A LOT OF RESIDUAL MOISTURE ON FRIDAY
WHICH MEANS THERE PROBABLY WILL NOT BE MUCH SUNSHINE. AS A RESULT...
HIGHS WILL ONLY WARM A FEW DEGREES AND BE SLIGHTLY BELOW NORMAL.
SCHNEIDER
&&
.LONG TERM...SATURDAY LOOKS AND WILL LIKELY BE THE WARMEST DAY OF
THE WEEK WITH HIGHS IN THE 70S MANY AREAS AS A SHORT WAVE UPPER
RIDGE MOVES OVERHEAD. A FRONTAL SYSTEM WILL BE APPROACHING FROM THE
WEST SATURDAY NIGHT AND SUNDAY. MODELS ARE HAVING A HARD TIME
AGREEING ON WHEN THIS SYSTEM WILL MAKE LANDFALL AND THERE HAS BEEN A
FAIR AMOUNT OF RUN TO RUN WAFFLING AS WELL. IF THE GFS IS CORRECT...
MOST OF THE AREA WILL REMAIN DRY AND HIGHS WILL BE SIMILAR TO
SATURDAY. IF THE ECMWF IS CORRECT...IT WILL BE A RAINY AND COOLER
DAY WITH HIGHS IN THE 60S. ANOTHER RELATIVELY WET FRONT WILL MOVE
ONSHORE AROUND MONDAY NIGHT. CONFIDENCE IN THE TIMING AND OTHER
SPECIFICS WITH THIS FRONT IS LOW FOR NOW. SCHNEIDER
&&
.AVIATION...UPPER LEVEL LOW OFF THE SOUTH WASHINGTON COAST MOVING
INTO NORTHWESTERN OREGON AND SOUTHWESTERN WASHINGTON TODAY. SOUTH
SOUTHEASTERLY FLOW ALOFT BECOMING MORE SOUTHEASTERLY LATE MORNING.
AIR MASS BECOMING MORE UNSTABLE AFTER 18Z WITH MOSTLY MID LEVEL
MOISTURE.
DOPPLER RADAR SHOWS JUST A FEW SHOWERS AROUND STEVENS PASS AT 10Z.
MOSTLY MID LEVEL MOISTURE OVER THE AREA WITH A SCATTERED TO BROKEN
DECK AROUND 6000 FEET AND ANOTHER SCATTERED TO BROKEN LAYER 8000 TO
12000 FEET. LITTLE CHANGE IN THE CLOUD COVER THROUGHOUT THE DAY WITH
THE SHOWER ACTIVITY INCREASING AFTER 21Z THEN DECREASING AFTER
SUNSET.
KSEA...MID LEVEL CLOUDS THROUGHOUT THE DAY WITH THE LOWER LAYER NEAR
6000 FEET GOING BROKEN AT TIMES. SOUTHERLY WINDS 4 TO 8 KNOTS. FELTON
&&
.MARINE...HIGH PRES OVER THE OFFSHORE WATERS AND LOW PRES OVER
INTERIOR B.C. WILL MAINTAIN ONSHORE FLOW ACROSS WESTERN WASHINGTON
THROUGH FRIDAY. THE ONSHORE GRADIENTS WILL STRENGTHEN TONIGHT AS
PRESSURES FALL OVER THE INTERIOR OF BRITISH COLUMBIA THIS AFTERNOON.
A GALE WARNING HAS BEEN ISSUED FOR THE CENTRAL AND EASTERN STRAIT OF
JUAN DE FUCA FOR TONIGHT. IN ADDITION A SMALL CRAFT ADVISORY HAS
BEEN ISSUED FOR THE NORTHERN INLAND WATERS. WINDS EASING LATER
THURSDAY AS SURFACE HIGH PRESSURE BEGINS TO BUILD INTO THE AREA AND
PRESSURES RISE OVER BRITISH COLUMBIA. HIGH PRESSURE OVER THE WATERS
ON FRIDAY. A FRONT WILL APPROACH THE COASTAL WATERS ON SATURDAY AND
MOVE INLAND ON SUNDAY. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING CENTRAL AND EASTERN STRAIT.
SMALL CRAFT ADVISORY NORTHERN INLAND WATERS.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 191026
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
325 AM PDT WED JUN 19 2013
.SYNOPSIS...AN UPPER LOW WILL PRODUCE SCATTERED SHOWERS AND A FEW
THUNDERSTORMS TODAY. A TROUGH ROTATING WESTWARD TO THE NORTH OF THE
LOW WILL BRING A PERIOD OF STEADIER AND HEAVIER RAIN TO MUCH OF THE
AREA THURSDAY AND THURSDAY NIGHT. WEAK HIGH PRESSURE WILL BUILD
INTO THE AREA FRIDAY NIGHT AND SATURDAY. A SERIES OF FRONTS WILL
BRING WET WEATHER AGAIN EARLY NEXT WEEK.
&&
.SHORT TERM...AN UPPER LOW JUST OFF THE COAST WILL SLOWLY SHIFT
INLAND OVER OREGON TODAY. MOIST AND UNSTABLE SOUTHERLY FLOW ALOFT
WILL WEAKEN AND BECOME MORE EASTERLY TODAY. THERE WILL BE ISOLATED
TO SCATTERED SHOWERS AGAIN TODAY...MOSTLY DIURNALLY DRIVEN IN THE
AFTERNOON OVER THE CASCADES AND SOUTH PART OF THE FORECAST AREA
CLOSEST TO THE UPPER LOW. THE THUNDERSTORM THREAT LOOKS MINIMAL AT
BEST TODAY WITH LIFTED INDICES THIS AFTERNOON ONLY DOWN TO AROUND
ZERO AND CAPE VALUES BARELY CRACKING 100 J/KG. THERE MIGHT BE AN
ISOLATED STORM OR TWO OVER THE SOUTH INTERIOR OR OVER THE CASCADES
LATER TODAY BUT THE CHANCES ARE NOT HIGH ENOUGH TO MENTION IN THE
FORECAST. HIGHS WILL COOL A FEW DEGREES TODAY AS THE UPPER LOW MOVES
CLOSER. HOWEVER...GUIDANCE HAS HAD A NOTICEABLE COOL BIAS THE LAST
FEW DAYS. THE FORECAST HIGHS FOR TODAY HAVE BEEN BUMPED UP TO
ACCOUNT FOR THIS.
THE UPPER LOW WILL SHIFT OVER EASTERN WASHINGTON ON THURSDAY. A
RATHER WELL DEFINED SHORT WAVE ROTATING AROUND THE TOP OF THE UPPER
LOW WILL SPREAD STEADIER RAIN INTO WESTERN WASHINGTON EARLY
THURSDAY. THE NORTHERN HALF OF THE FORECAST AREA WILL SEE THE BRUNT
OF THE RAIN WITH AMOUNTS RAPIDLY DROPPING OFF TO THE SOUTH. THE
HEAVIEST RAINS ARE EXPECTED TO BE OVER THE NORTHERN CASCADES WHERE
1-2 INCHES ARE A GOOD BET BY LATE THURSDAY WITH LOCALLY HIGHER
AMOUNTS POSSIBLE. WITH ALL THE CLOUDS AND RAIN...HIGHS WILL STRUGGLE
TO CLIMB OUT OF THE LOWER 60S...ESPECIALLY FROM SEATTLE NORTH. ALSO
OF NOTE...ONSHORE GRADIENTS WILL TIGHTEN IN RESPONSE TO FALLING
PRESSURES OVER SOUTHERN BRITISH COLUMBIA AS THE SHORT WAVE ROTATES
THROUGH. THIS WILL GIVE BREEZY SOUTHERLY WINDS TO PARTS OF THE AREA
THURSDAY...SOMEWHAT UNUSUAL FOR LATE JUNE.
SCATTERED SHOWERS WILL BE TAPERING ON FRIDAY AS THE UPPER LOW
WEAKENS AND PULLS AWAY FROM THE AREA. EVEN THOUGH SHOWERS WILL BE
DECREASING...THERE WILL BE A LOT OF RESIDUAL MOISTURE ON FRIDAY
WHICH MEANS THERE PROBABLY WILL NOT BE MUCH SUNSHINE. AS A RESULT...
HIGHS WILL ONLY WARM A FEW DEGREES AND BE SLIGHTLY BELOW NORMAL.
SCHNEIDER
&&
.LONG TERM...SATURDAY LOOKS AND WILL LIKELY BE THE WARMEST DAY OF
THE WEEK WITH HIGHS IN THE 70S MANY AREAS AS A SHORT WAVE UPPER
RIDGE MOVES OVERHEAD. A FRONTAL SYSTEM WILL BE APPROACHING FROM THE
WEST SATURDAY NIGHT AND SUNDAY. MODELS ARE HAVING A HARD TIME
AGREEING ON WHEN THIS SYSTEM WILL MAKE LANDFALL AND THERE HAS BEEN A
FAIR AMOUNT OF RUN TO RUN WAFFLING AS WELL. IF THE GFS IS CORRECT...
MOST OF THE AREA WILL REMAIN DRY AND HIGHS WILL BE SIMILAR TO
SATURDAY. IF THE ECMWF IS CORRECT...IT WILL BE A RAINY AND COOLER
DAY WITH HIGHS IN THE 60S. ANOTHER RELATIVELY WET FRONT WILL MOVE
ONSHORE AROUND MONDAY NIGHT. CONFIDENCE IN THE TIMING AND OTHER
SPECIFICS WITH THIS FRONT IS LOW FOR NOW. SCHNEIDER
&&
.AVIATION...UPPER LEVEL LOW OFF THE SOUTH WASHINGTON COAST MOVING
INTO NORTHWESTERN OREGON AND SOUTHWESTERN WASHINGTON TODAY. SOUTH
SOUTHEASTERLY FLOW ALOFT BECOMING MORE SOUTHEASTERLY LATE MORNING.
AIR MASS BECOMING MORE UNSTABLE AFTER 18Z WITH MOSTLY MID LEVEL
MOISTURE.
DOPPLER RADAR SHOWS JUST A FEW SHOWERS AROUND STEVENS PASS AT 10Z.
MOSTLY MID LEVEL MOISTURE OVER THE AREA WITH A SCATTERED TO BROKEN
DECK AROUND 6000 FEET AND ANOTHER SCATTERED TO BROKEN LAYER 8000 TO
12000 FEET. LITTLE CHANGE IN THE CLOUD COVER THROUGHOUT THE DAY WITH
THE SHOWER ACTIVITY INCREASING AFTER 21Z THEN DECREASING AFTER
SUNSET.
KSEA...MID LEVEL CLOUDS THROUGHOUT THE DAY WITH THE LOWER LAYER NEAR
6000 FEET GOING BROKEN AT TIMES. SOUTHERLY WINDS 4 TO 8 KNOTS. FELTON
&&
.MARINE...HIGH PRES OVER THE OFFSHORE WATERS AND LOW PRES OVER
INTERIOR B.C. WILL MAINTAIN ONSHORE FLOW ACROSS WESTERN WASHINGTON
THROUGH FRIDAY. THE ONSHORE GRADIENTS WILL STRENGTHEN TONIGHT AS
PRESSURES FALL OVER THE INTERIOR OF BRITISH COLUMBIA THIS AFTERNOON.
A GALE WARNING HAS BEEN ISSUED FOR THE CENTRAL AND EASTERN STRAIT OF
JUAN DE FUCA FOR TONIGHT. IN ADDITION A SMALL CRAFT ADVISORY HAS
BEEN ISSUED FOR THE NORTHERN INLAND WATERS. WINDS EASING LATER
THURSDAY AS SURFACE HIGH PRESSURE BEGINS TO BUILD INTO THE AREA AND
PRESSURES RISE OVER BRITISH COLUMBIA. HIGH PRESSURE OVER THE WATERS
ON FRIDAY. A FRONT WILL APPROACH THE COASTAL WATERS ON SATURDAY AND
MOVE INLAND ON SUNDAY. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING CENTRAL AND EASTERN STRAIT.
SMALL CRAFT ADVISORY NORTHERN INLAND WATERS.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 190417
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 PM PDT TUE JUN 18 2013
.SYNOPSIS...AN UPPER LOW JUST OFF THE COAST WILL CONTINUE TO BRING
SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE REGION THROUGH
WEDNESDAY. AN ASSOCIATED TROUGH ROTATING WESTWARD TO THE NORTH OF
THE LOW WILL LIKELY BRING A PERIOD OF RAIN TO MUCH OF WESTERN
WASHINGTON WEDNESDAY NIGHT AND THURSDAY. THERE COULD BE LOCALLY
HEAVY RAIN ACROSS THE NORTH CASCADES FROM THIS SYSTEM. WEAK HIGH
PRESSURE WILL BUILD INTO THE AREA FRIDAY NIGHT AND SATURDAY. ANOTHER
WET WEATHER PATTERN IS LIKELY TO DEVELOP EARLY NEXT WEEK WITH
SEVERAL FRONTS MOVING ACROSS THE AREA.
&&
.SHORT TERM...THE UPPER LOW JUST OFF THE COAST IS GRADUALLY
WEAKENING AND EVER SO SLOWLY BEGINNING ITS DRIFT SOUTHEASTWARD. OVER
THE NEXT COUPLE OF DAYS THE LOW WILL TRACK EASTWARD ACROSS NORTHERN
OREGON AND THEN NORTHEAST TO NORTHERN IDAHO BY THU. SHOWERS AND
THUNDERSTORMS THIS EVENING WILL GRADUALLY DISSIPATE OVERNIGHT WITH
ANOTHER ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS TOMORROW WITH
DAYTIME HEATING.
THE MODELS... WHILE NOT AGREEING ON ALL OF THE DETAILS... CONTINUE
TO INDICATE A VORT MAX WILL ROTATE WESTWARD ACROSS THE NORTH
CASCADES AND POSSIBLY THE OLYMPICS BRINGING A PERIOD OF RAIN...
POTENTIALLY HEAVY... TO THE NORTH CASCADES AND NORTHERN LOWLANDS.
SOME MODELS ARE INDICATING OVER 4 INCHES OF RAIN IN THE VICINITY OF
MT BAKER AND NORTH CASCADES IN A 36 HOUR PERIOD ENDING THURSDAY
NIGHT.
FRIDAY INTO SATURDAY BRINGS A BIT OF A BREAK TO THE SHOWERY WEATHER
WITH WARMER AND DRIER CONDITIONS AS THE CLOSED LOW MOVES EASTWARD. A
NEW TROUGH EMBEDDED IN WESTERLY FLOW WILL BRING A CHANCE OF RAIN
BACK TO THE AREA BY SATURDAY NIGHT. COLMAN
&&
.LONG TERM...FROM PREVIOUS DISCUSSION...TEMPORARY HIGH PRESSURE WILL
BUILD INTO THE AREA FRIDAY NIGHT AND SATURDAY. A FRONT MAY REACH
WESTERN WA SAT NIGHT AND SUNDAY MORNING. THERE IS A DIFFERENCE
BETWEEN THE GFS AND THE ECMWF THIS WEEKEND...IF THE 12Z GFS IS
CORRECT IT WILL NOT RAIN MUCH...MAINLY JUST ON THE COAST AND IN THE
OLYMPICS AND THAT MODEL SHOWED NO RAIN AT ALL FOR A GOOD PORTION OF
THE SEATTLE EVERETT AREA. THE EURO ON THE OTHER HAND GIVES MUCH OF
WESTERN WA A GOOD SOAKING RAIN WITH MOST OF WESTERN WA GETTING AT
LEAST AN INCH OF RAIN. AFTER THAT...RAIN IS LIKELY AT TIMES SUN NITE
THRU NEXT TUE AS A NEW UPPER TROUGH MOVES INTO THE NE PACIFIC.
&&
.AVIATION...UPPER LEVEL LOW OFF THE COAST TUESDAY EVENING WILL MOVE
SOUTHEAST INTO NORTHWEST OREGON WEDNESDAY MORNING. SOUTH
SOUTHEASTERLY FLOW ALOFT BECOMING MORE SOUTHEASTERLY WEDNESDAY
MORNING. AIR MASS STABILIZING SOMEWHAT AFTER 06Z.
DOPPLER RADAR SHOWS SHOWER ACTIVITY PRETTY MUCH CONFINED TO THE
MOUNTAINS AT 04Z. SCATTERED TO BROKEN DECK AOA 10000 FEET OVER THE
AREA. THESE CONDITIONS WILL CONTINUE INTO WEDNESDAY AFTERNOON.
SURFACE GRADIENTS ONSHORE OVERNIGHT INTO WEDNESDAY MORNING WHICH
BRINGS UP THE POSSIBILITY OF A STRATUS DECK AROUND 2000 FEET FORMING
AFTER SUNRISE. WHAT STRATUS THAT DOES FORM WILL NOT BE WIDESPREAD
AND WILL ONLY LAST UNTIL LATE MORNING AT THE LATEST. AIR MASS
BECOMING MORE UNSTABLE WEDNESDAY AFTERNOON FOR ANOTHER ROUND OF
SCATTERED SHOWERS.
KSEA...MOSTLY MID LEVEL CLOUD COVER OVERNIGHT INTO WEDNESDAY.
SOME STRATUS FORMING OVER THE SOUND WEDNESDAY MORNING COULD FLOAT
OVER THE AIRPORT FOR A COUPLE OF HOURS IN THE MORNING. CONFIDENCE
NOT REAL HIGH IN THIS SCENARIO. WILL GO WITH A TEMPO GROUP WITH 2000
BROKEN FOR A FEW HOURS AFTER SUNRISE. FELTON
&&
.MARINE...A 1012 MB SURFACE LOW WILL SHIFT EAST AND DIMINISH OVER
THE COASTAL WATERS TONIGHT. HIGH PRES OVER THE OFFSHORE WATERS AND
LOW PRES OVER INTERIOR B.C. WILL MAINTAIN ONSHORE FLOW ACROSS
WESTERN WASHINGTON WEDNESDAY THROUGH FRIDAY. THE CENTRAL AND EAST
STRAIT OF JUAN DE FUCA MAY SEE GALE FORCE WESTERLY WINDS WEDNESDAY
EVENING. WINDS WILL GRADUALLY EASE THROUGH THE STRAIT THURSDAY
MORNING. A FRONT WILL APPROACH THE COASTAL WATERS ON
SATURDAY...MOVING INLAND SAT NIGHT. 33/FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 182142
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
240 PM PDT TUE JUN 18 2013
.SYNOPSIS...AN UPPER LOW WILL BRING SCATTERED SHOWERS AND A FEW
THUNDERSTORMS TO THE REGION THROUGH WEDNESDAY. SHOWERS OR RAIN WILL
LIKELY INCREASE WEDNESDAY NIGHT AND THURSDAY. WEAK HIGH PRESSURE
WILL BUILD INTO THE AREA FRIDAY NIGHT AND SATURDAY. A WET WEATHER
PATTERN IS LIKELY TO DEVELOP EARLY NEXT WEEK.
&&
.SHORT TERM...AN UPPER LOW JUST OFF THE COAST WILL SHIFT INLAND OVER
THE NEXT COUPLE OF DAYS. THERE WILL BE SCATTERED SHOWERS...MAINLY
AFTERNOON AND EVENING WITH A CHANCE OF TSTMS...MAINLY FOR THE
CASCADES IN THE AFTERNOON AND EVENING HOURS. AS THE LOW SHIFTS
INLAND THE FLOW ALOFT WILL BACK FROM SOUTH TODAY TO MORE EASTERLY
THURSDAY AND THERE IS A GOOD CHANCE THAT A SOAKING RAIN WILL DEVELOP
WEDNESDAY NIGHT OR THURSDAY AS WRAP AROUND MOISTURE SPREADS INTO
WESTERN WA. SHOWERS SHOULD DECREASE THU NIGHT AND THEN END FRIDAY
MORNING.
&&
.LONG TERM...TEMPORARY HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY
NIGHT AND SATURDAY. A FRONT MAY REACH WESTERN WA SAT NIGHT AND
SUNDAY MORNING. THERE IS A DIFFERENCE BETWEEN THE GFS AND THE ECMWF
THIS WEEKEND...IF THE 12Z GFS IS CORRECT IT WILL NOT RAIN
MUCH...MAINLY JUST ON THE COAST AND IN THE OLYMPICS AND THAT MODEL
SHOWED NO RAIN AT ALL FOR A GOOD PORTION OF THE SEATTLE EVERETT
AREA. THE EURO ON THE OTHER HAND GIVES MUCH OF WESTERN WA A GOOD
SOAKING RAIN WITH MOST OF WESTERN WA GETTING AT LEAST AN INCH OF
RAIN. AFTER THAT...RAIN IS LIKELY AT TIMES SUN NITE THRU NEXT TUE AS
A NEW UPPER TROUGH MOVES INTO THE NE PACIFIC.
&&
.AVIATION...AN UPPER LEVEL LOW WILL SPIN OFFSHORE TONIGHT WITH
SOUTHERLY FLOW ALOFT OVER WESTERN WA. EXPECT ISOLATED TO SCATTERED
SHOWERS ACROSS THE REGION. INSTABILITY WILL PEAK LATE THIS AFTERNOON
AND EVENING WITH ISOLATED THUNDERSTORMS POSSIBLE...MAINLY COAST AND
MOUNTAINS. VFR CONDITIONS WILL PREVAIL...HOWEVER MAY SEE PATCHY LOW
CLOUDS AND MVFR CIGS EARLY WED MORNING. THE UPPER LOW WILL SHIFT
INLAND ON WED WITH SHOWERS MAINLY OVER THE CASCADES. 33
KSEA...VFR CONDITIONS WILL PREVAIL TONIGHT WITH SOUTHERLY FLOW AT
THE SURFACE. EXPECT ISOLATED SHOWERS IN THE VICINITY LATE THIS
AFTERNOON AND EVENING. MAY SEE PATCHY LOW CLOUDS EARLY WED MORNING
FOR BRIEF MVFR CONDITIONS. 33
&&
.MARINE...A 1011 MB SURFACE LOW WILL SHIFT EAST AND DIMINISH OVER
THE COASTAL WATERS TONIGHT. HIGH PRES OVER THE OFFSHORE WATERS AND
LOW PRES OVER INTERIOR B.C. WILL MAINTAIN S/SW FLOW ACROSS WESTERN
WA WED THROUGH FRIDAY. THE CENTRAL AND EAST STRAIT OF JUAN DE FUCA
MAY SEE GALE FORCE WESTERLY WINDS WED EVENING. WINDS WILL GRADUALLY
EASE THROUGH THE STRAIT THU MORNING. A FRONT WILL APPROACH THE
COASTAL WATERS ON SATURDAY...MOVING INLAND SAT NIGHT. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS TODAY UNTIL 5 PM
TONIGHT.
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 181624
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
925 AM PDT TUE JUN 18 2013
.SYNOPSIS...AN UPPER LOW WILL BRING SCATTERED SHOWERS AND A FEW
THUNDERSTORMS TO THE REGION THROUGH WEDNESDAY. A PERIOD OF RAIN IS
POSSIBLE WEDNESDAY NIGHT AND THURSDAY. WEAK HIGH PRESSURE WILL BUILD
INTO THE AREA FRIDAY NIGHT AND SATURDAY. WEAK FRONTS MAY AFFECT
WESTERN WASHINGTON OVER THE WEEKEND...WITH A CHANCE OF RAIN MAINLY
ON THE COAST. STRONGER WETTER FRONTS ARE LIKELY EARLY NEXT WEEK.
&&
.SHORT TERM...AN UPPER LOW JUST OFF THE COAST TODAY WILL SHIFT
INLAND OVER THE NEXT COUPLE OF DAYS. THERE WILL BE SCATTERED
SHOWERS...MAINLY AFTERNOON AND EVENING WITH A CHANCE OF TSTMS. THE
BEST CHANCE FOR A FEW TSTMS IS OVER THE MOUNTAINS AND SOUTH OF
SEATTLE AND NOT AT ALL LIKELY NEAR THE SAN JUANS. AS THE LOW SHIFTS
INLAND THE FLOW ALOFT WILL BACK FROM SOUTH TODAY TO MORE THURSDAY.
THE 12Z GFS HAS A GOOD SOAKING RAIN FOR WRN WA THU...WHILE THE NAM
KEEPS MOST OF THE PRECIP OVER THE CASCADES AND NORTH OF SEATTLE.
&&
.LONG TERM...A 1020MB SURFACE HIGH AND WEAK UPPER RIDGE WILL BUILD
INTO THE AREA FRIDAY AND SATURDAY. A WEAK FRONT REACHES THE COAST
LATE SATURDAY AND DRIES UP BY DAYBREAK SUNDAY...THE 12Z GFS IS DRIER
THAN THE PREVIOUS RUN AND HAS ONLY A LITTLE LIGHT RAIN FOR THE NORTH
COAST. BUT ANOTHER FRONT IS SHOWN IN THE GFS SPREADING RAIN TO THE
COAST SUNDAY AFTERNOON SO WILL PROBABLY HAVE TO CHANGE THE FORECAST
SUNDAY AND GET AT LEAST A CHANCE OF RAIN IN THERE UNLESS THE 12Z
EURO IS DRY. PERIODS OF WET WEATHER ARE LIKELY MONDAY AND TUESDAY AS
A BIG UPPER TROUGH DEVELOPS IN THE NE PAC.
&&
.AVIATION...AN UPPER LEVEL LOW WILL SPIN OFFSHORE TODAY WITH
SOUTHERLY FLOW ALOFT OVER WESTERN WA. EXPECT ISOLATED TO SCATTERED
SHOWERS ACROSS THE REGION. INSTABILITY WILL INCREASE THIS AFTERNOON
WITH ISOLATED THUNDERSTORMS POSSIBLE...MAINLY COAST AND MOUNTAINS.
VFR CONDITIONS WILL PREVAIL. THE UPPER LOW WILL SHIFT INTO OREGON
TONIGHT WITH SHOWERS MAINLY OVER THE CASCADES. 33
KSEA...VFR CONDITIONS WILL PREVAIL TODAY WITH SOUTHERLY FLOW AT THE
SURFACE. EXPECT ISOLATED SHOWERS IN THE VICINITY THIS AFTERNOON AND
EVENING. 33
&&
.MARINE...A 1011 MB SURFACE LOW WILL SHIFT EAST AND DIMINISH OVER
THE COASTAL WATERS TODAY. MODELS SHOW SOUTH WINDS OF 15 TO 25 KT
OVER THE OUTER COASTAL WATER ZONES - A SMALL CRAFT ADVISORY REMAINS
IN EFFECT. ELSEWHERE...WINDS ARE GENERALLY LIGHT. HIGH PRES OVER THE
OFFSHORE WATERS AND LOW PRES OVER INTERIOR B.C. WILL MAINTAIN S/SW
FLOW ACROSS WESTERN WA WED THROUGH FRIDAY. SMALL CRAFT ADVISORY
WESTERLIES ARE POSSIBLE AT THE CENTRAL AND EASTERN STRAIT OF JUAN DE
FUCA IN THE EVENING HOURS. A FRONT WILL APPROACH THE COASTAL WATERS
ON SATURDAY. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS TODAY.
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 181021
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
320 AM PDT TUE JUN 18 2013
.SYNOPSIS...AN UPPER LOW JUST OFF THE COAST WILL GRADUALLY MOVE
INLAND THIS WEEK. THE LOW WILL BRING A CHANCE OF SHOWERS TO THE
REGION...AND ISOLATED THUNDERSTORMS AT TIMES AS WELL. AN UPPER RIDGE
WILL MOVE OVER THE REGION NEXT WEEKEND FOR WARMER AND DRIER WEATHER.
&&
.SHORT TERM...AN UPPER LOW OFF THE COAST WILL SHIFT INLAND OVER
OREGON TONIGHT...MOVE NORTHEAST TO NORTHERN IDAHO WEDNESDAY AND
REMAIN QUASI-STATIONARY ON THURSDAY. THIS LOW WILL BRING SHOWERS TO
THE AREA AT TIMES...FIRST IN SOUTHERLY FLOW ALOFT...THEN IN EASTERLY
WRAP-AROUND FLOW. THERE WILL BE A BIT OF LULL IN THE SHOWER ACTIVITY
THIS MORNING AS THE ORGANIZED BAND OF SHOWERS THAT MOVED THROUGH THE
AREA YESTERDAY EVENING HAS PUSHED NORTH INTO CANADA. SCATTERED
SHOWERS WILL REDEVELOP BY THIS AFTERNOON WITH DAYTIME HEATING...
MOSTLY OVER THE SOUTHERN HALF OF THE FORECAST AREA CLOSEST TO THE
UPPER LOW WHERE THE AIR WILL BE MOST UNSTABLE. AN ISOLATED
THUNDERSTORM CANNOT BE RULED OUT OVER THE SOUTH PART OF THE AREA AND
OVER THE CASCADES THIS AFTERNOON AND EVENING BUT IT DOES NOT LOOK
LIKE A BIG OUTBREAK. HIGHS WILL BE NEAR NORMAL TODAY...THEN A FEW
DEGREES BELOW NORMAL WEDNESDAY AND THURSDAY WITH THE UPPER LOW
NEARBY. SCHNEIDER
&&
.LONG TERM...AN UPPER LOW WILL REMAIN OVER EASTERN WASHINGTON OR
NORTHERN IDAHO FRIDAY...KEEPING A THREAT OF SHOWERS FOR WESTERN
WASHINGTON. THERE ARE SOME HINTS THAT THE LOW WILL BE WEAKENING AND
SHIFTING SLIGHTLY EAST BY THIS TIME BUT THE MODELS ARE HAVING A HARD
TIME PINNING DOWN THE DETAILS. A SHORT WAVE UPPER RIDGE WILL MOVE
OVER THE AREA FRIDAY NIGHT AND SATURDAY FOR DRIER AND WARMER
WEATHER. HOWEVER...THE MOST RECENT MODELS NOW SHOW A SHORT WAVE
UPPER TROUGH REACHING THE COAST BY SATURDAY AFTERNOON WITH SOME RAIN
SPREADING ONSHORE. IF SUBSEQUENT MODEL RUNS CONTINUE TO SHOW THIS
NEW WRINKLE...RAIN WILL NEED TO BE INTRODUCED INTO THE CURRENT DRY
SATURDAY AFTERNOON THROUGH SUNDAY MORNING FORECAST. ALL MODELS SHOW
A WET AND FAIRLY ROBUST...FOR LATE JUNE...FRONT REACHING THE AREA
MONDAY. SCHNEIDER
&&
.AVIATION...AN UPPER LEVEL LOW OFFSHORE WILL MOVE SOUTHEAST INTO
WESTERN OREGON WEDNESDAY MORNING. SOUTHERLY FLOW ALOFT BECOMING
SOUTHEASTERLY LATE IN THE DAY. THE AIR MASS WILL REMAIN SOMEWHAT
UNSTABLE TODAY WITH MAINLY MID LEVEL MOISTURE.
A FEW SHOWERS NEAR THE CASCADES EARLY THIS MORNING OTHERWISE JUST
SOME MID LEVEL CLOUDS OVER THE AREA. UPPER LEVEL LOW SLOWLY MOVING
SOUTHEAST WITH MORE SHOWERS DEVELOPING IN THE SOMEWHAT UNSTABLE AIR
MASS THIS AFTERNOON. WIDE VARIETY OF CLOUD COVER OVER THE AREA THIS
MORNING WITH SOME CLEAR AREAS...SOME AREAS OF 6000 TO 8000
BROKEN...AND AN AREA OF LOWER CEILINGS...AROUND 2000 FEET...NEAR THE
OLYMPICS. EXPECT THE CEILINGS TO REMAIN AOA 5000 FEET EXCEPT NEAR
THE OLYMPICS EARLY THIS MORNING. EVEN WITH THE SHOWERS THIS
AFTERNOON INTO THE EVENING HOURS CEILINGS WILL REMAIN VFR BUT THERE
IS THE POTENTIAL FOR BRIEF VISIBILITY RESTRICTIONS...3-5SM WITH THE
SHOWERS INTO THE EARLY EVENING HOURS. FELTON
KSEA...MID LEVEL DECK AOA 5000 FEET OFF AN ON INTO THIS EVENING.
SHOWERS REMAINING WEST OF THE TERMINAL THIS AFTERNOON. SOUTHERLY
WINDS 4 TO 8 KNOTS BECOMING TRYING TO BECOMING NORTHWESTERLY THIS
AFTERNOON BUT ONLY GETTING TO 230-250 DEGREES. FELTON
&&
.MARINE...A 1010 MB LOW OVER THE OFFSHORE WATERS WILL MOVE EAST
SLIGHTLY AND DISSIPATE TODAY. LOW GETTING CLOSE ENOUGH TO THE OUTER
COASTAL WATERS FOR SMALL CRAFT ADVISORY SOUTHERLY THERE TODAY.
SURFACE HIGH PRESSURE REMAINING OFFSHORE WITH LOWER PRESSURE INLAND
RESULTING IN ONSHORE FLOW TONIGHT THROUGH FRIDAY. SMALL CRAFT
ADVISORY WESTERLIES ARE POSSIBLE AT THE CENTRAL AND EASTERN STRAIT
OF JUAN DE FUCA IN THE EVENING HOURS WEDNESDAY THROUGH FRIDAY. AN
ORGANIZED FRONT WILL APPROACH THE COASTAL WATERS ON SATURDAY. FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS TODAY.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 180402
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT MON JUN 17 2013
.SYNOPSIS...AN UPPER LEVEL LOW SPINNING JUST OFF THE COAST WILL
GRADUALLY MOVE INLAND OVER THE PACIFIC NORTHWEST THIS WEEK. THE LOW
WILL BRING AN INCREASING CHANCE OF SHOWERS TO THE REGION...AND A
CHANCE OF A FEW THUNDERSTORMS AT TIMES AS WELL. AN UPPER LEVEL RIDGE
WILL MOVE OVER THE REGION NEXT WEEKEND FOR A RETURN TO WARMER AND
DRIER WEATHER.
&&
.SHORT TERM...THE IDEA OF KEEPING THE ISOLATED THUNDERSTORMS LIMITED
TO THE SOUTHWEST PART OF THE FORECAST AREA AND CASCADES HAS WORKED
OUT WELL FOR THE EARLY EVENING. SUPPRESSION OVER CENTRAL PUGET SOUND
WAS PRETTY EFFECTIVE AT KILLING CELLS AS THEY MOVED NORTH INTO THE
SOUTH SOUND. LIGHTNING WAS PRETTY MUCH LIMITED TO LEWIS COUNTY AND
THE CASCADES.
YET THINGS HAVE NOW CHANGED AS A WESTERLY SURGE IN THE LOW-LEVEL
WINDS PUSHED ONSHORE OVER THE LAST COUPLE OF HOURS. THIS WAS WELL
HANDLED IN THE UW 1 1/3KM WRF. THE SURGE SEEMS TO HAVE ELIMINATED
THE SUPPRESSION OVER PUGET SOUND AND SHOWERS ASSOCIATED WITH THE
AXIS OF A SPIRAL BAND FROM THE OFFSHORE LOW SEEM TO BE HOLDING
TOGETHER NOW AS THEY ROTATE NORTH. THERE WAS ONE LIGHTNING STRIKE
ABOUT 830 PM IN THE SOUTH SOUND. THE HIGHEST RESOLUTION MESOSCALE
MODELS (E.G.,THE LATEST 3-KM HRRR) SUPPORT AT LEAST SOME RISK OF AN
AREA OF MORE ORGANIZED SHOWERS WITH A FEW STRONGER CELLS WORKING
THEIR WAY ALL THE WAY UP THE SOUND THROUGH ABOUT MIDNIGHT OR SO.
THE SHOWERS HAVE ALSO BEEN PRETTY INTENSE ALBEIT BRIEF. RELUCTANT TO
CHANGE THE OVERALL FORECAST TO INCLUDE ISOLATED THUNDERSTORMS;
RATHER FEEL IT IS BETTER AT THIS POINT TO DEAL WITH THE ISOLATED
CELLS USING NOWCASTS. ISSUED ONE ABOUT AN HOUR AGO. ONCE THE SHOWERS
AND ISOLATED THUNDERSTORMS ROTATE NORTH LATER THIS EVENING THINGS
SHOULD QUIET DOWN RATHER QUICKLY.
THE NEW MODELS CONTINUE WITH THE IDEA OF THE UPPER LEVEL LOW JUST
OFFSHORE GRADUALLY DRIFTING ACROSS NORTHERN OREGON THROUGH ABOUT
WEDNESDAY AND THEN NORTHEAST INTO THE IDAHO PANHANDLE ON THURSDAY.
MODELS ALSO CONTINUE TO WRAP SIGNIFICANT MOISTURE WITH MODERATE
PRECIPITATION BACK ACROSS THE CASCADES AND WESTERN WASHINGTON WED
AND THU. THIS ALL HANDLED WELL IN THE CURRENT FORECAST. COLMAN
&&
.AVIATION...AN UPPER LEVEL LOW OFFSHORE WILL KEEP SOUTHERLY FLOW
ALOFT OVER WASHINGTON THROUGH TUESDAY. THE AIR MASS WILL REMAIN
MOIST AND SOMEWHAT UNSTABLE FOR ISOLATED TO SCATTERED SHOWERS ACROSS
THE CWA...WITH A CHANCE OF ISOLATED THUNDERSTORMS OVER THE PUGET
SOUND AREA AND THE CASCADES UNTIL 06Z.
BAND OF SHOWERS NEAR KOLM AT 0330Z MOVING NORTH TO NEAR KSEA BY 05Z
KPAE 06Z THEN WEAKENING AS IT MOVES FARTHER NORTH. VISIBILITIES
LOWERING DOWN TO AS LOW AS 1 SM WITH THESE SHOWERS. CEILINGS
LOWERING TO NEAR 4000 FEET. CEILINGS REBOUNDING TO AOA 5000 FEET
WITH UNRESTRICTED VISIBILITIES SHORTLY AFTER THE BAND PASSES THROUGH
THE AREA. CEILINGS REMAINING AOA 5000 FEET INTO TUESDAY MORNING
EXCEPT ALONG THE COAST WHERE CEILINGS WILL LOWER TO THE 1000 TO 2000
FEET RANGE AT TIMES THROUGH 18Z TUESDAY. FELTON
KSEA...BAND OF SHOWERS REACHING THE TERMINAL ABOUT 05Z WITH
VISIBILITY LOWERING DOWN TO 4 SM AND CEILINGS LOWERING TO NEAR 4000
FEET. BAND MOVING QUICKLY NORTH WITH CONDITIONS IMPROVING BY 07Z.
CEILINGS AOA 5000 FEET THE REMAINDER OF THE NIGHT INTO TUESDAY
MORNING. GUSTY SOUTHWEST WINDS 10-15 KNOTS WITH GUSTS TO 20 KNOTS
BECOMING SOUTHERLY 4 TO 8 KNOTS BY 06Z. FELTON
&&
.MARINE...BRIEF PUSH OF SOUTHERLY WINDS AHEAD OF THE BAND OF SHOWERS
MOVING NORTH THROUGH THE SOUND THIS EVENING BUT WINDS SHOULD STAY 20
KNOTS OR LESS. ONSHORE GRADIENTS WEAKENING OVERNIGHT INTO TUESDAY
MORNING KEEPING WINDS BELOW SCA IN THE CENTRAL AND EASTERN STRAIT
OVERNIGHT.
A BROAD LOW PRES CENTER /1012MB/ WILL SLOWLY MOVE E OVER THE
OFFSHORE WATERS THROUGH TUE...THEN WEAKEN AS IT SHIFTS INLAND TUE
NIGHT. HIGH PRES OFFSHORE AND LOW PRES OVER INTERIOR B.C. WILL
MAINTAIN ONSHORE FLOW OVER THE WATERS INTO THE END OF THE WEEK.
FELTON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 172142
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
242 PM PDT MON JUN 17 2013
.SYNOPSIS...AN UPPER LEVEL LOW WILL MOVE OVER THE PACIFIC NORTHWEST
THIS WEEK. THE WEATHER SYSTEM WILL BRING AN INCREASING CHANCE OF
SHOWERS TO THE REGION...AND THERE WILL BE A CHANCE OF A FEW
THUNDERSTORMS AT TIMES. AN UPPER RIDGE WILL MOVE OVER THE REGION
NEXT WEEKEND FOR WARMER DRIER WEATHER.
&&
.SHORT TERM...THERE IS A WEAK LOOKING DISORGANIZED FRONTAL BOUNDARY
OFF THE COAST CURLING INTO AN UPPER LEVEL LOW CENTER OFFSHORE...IT
WILL BRING AN INCREASING CHANCE OF SHOWERS TO WESTERN WA THIS
EVENING. THE UPPER LOW WILL SHIFT OVER THE REGION THROUGH MIDWEEK.
MOIST UNSTABLE SOUTHERLY FLOW ALOFT WILL BRING SCATTERED SHOWERS AND
A FEW THUNDERSTORMS AT TIMES TO WRN WA THROUGH MIDWEEK. THERE IS A
CHANCE THAT SOME HEAVIER SHOWERS OR AN AREA OF RAIN DEVELOPS IN THE
SOUTH PART OF B.C. ALONG THE ALBERTA BORDER WEDNESDAY NIGHT AND
WORKS WWD AND THEN SOUTH INTO THE NORTH PART OF WESTERN WA THROUGH
THU AND SEVERAL INCHES OF RAIN MAY FALL IN THE NORTH CASCADES.
.LONG TERM...SHOWERS MAY PERSIST THROUGH FRIDAY AS THE UPPER LOW
CENTER SLOWLY SHIFTS FROM OVER WA THU TO MONTANA SAT. A RIDGE MIGHT
BUILD OVER THE AREA FOR THE WEEKEND AND A COUPLE OF SUNNY DAYS ARE
LIKELY IF THE ECMWF IS RIGHT...AND THEN A COLD FRONT COULD REACH THE
AREA MONDAY OR MONDAY NIGHT. THE GFS DOES NOT LOOK AS PROMISING FOR
A DRY SUNNY WEEKEND.
&&
.AVIATION...AN UPPER LEVEL LOW OFFSHORE WILL KEEP SOUTHERLY FLOW
ALOFT OVER WASHINGTON THROUGH TUESDAY. THE AIR MASS WILL REMAIN
MOIST AND SOMEWHAT UNSTABLE FOR ISOLATED TO SCATTERED SHOWERS ACROSS
THE CWA...WITH A CHANCE OF THUNDERSTORMS OVER THE CASCADES THIS
EVENING. CEILINGS ARE MAINLY IN A 4000-5000 FT RANGE...BUT MAY SEE
MVFR CONDITIONS TONIGHT AS A WEAK FRONTAL BOUNDARY SHIFTS INLAND. 33
KSEA...SHOWERS WILL INCREASE THIS EVENING AS A WEAK FRONTAL BOUNDARY
SHIFTS INLAND. SURFACE WINDS WILL STAY SOUTHERLY 4-8KT. 33
&&
.MARINE...LIGHT ONSHORE FLOW WILL CONTINUE ACROSS WESTERN WA
TONIGHT. MODELS ARE BACKING OFF ON THE WINDS THROUGH THE STRAIT OF
JUAN DE FUCA. PRES GRADIENTS ARE NEARLY FLAT THROUGH THE STRAIT THIS
AFTERNOON. MAY SEE A WEAK WESTERLY PUSH BUT WILL KEEPS WINDS AT
10-15 KT FOR THE CENTRAL AND EAST STRAIT.
A BROAD LOW PRES CENTER /1012MB/ WILL SLOWLY MOVE E OVER THE
OFFSHORE WATERS THROUGH TUE...THEN WEAKEN AS IT SHIFTS INLAND TUE
NIGHT. HIGH PRES OFFSHORE AND LOW PRES OVER INTERIOR B.C. WILL
MAINTAIN S/SW FLOW ACROSS WESTERN WA THROUGH THE END OF THE WEEK. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 171552
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
852 AM PDT MON JUN 17 2013
.SYNOPSIS...AN UPPER LEVEL LOW WILL MOVE OVER THE PACIFIC NORTHWEST
THIS WEEK. THE WEATHER SYSTEM WILL BRING AN INCREASING CHANCE OF
SHOWERS TO THE REGION...AND THERE WILL BE A CHANCE OF A FEW
THUNDERSTORMS AT TIMES. AN UPPER RIDGE WILL MOVE OVER THE REGION
NEXT WEEKEND FOR WARMER DRIER WEATHER.
&&
.SHORT TERM...AN UPPER LOW WILL SHIFT OVER THE REGION THROUGH
MIDWEEK. MOIST UNSTABLE SOUTHERLY FLOW ALOFT WILL BRING SCATTERED
SHOWERS. IT SHOULD BECOME UNSTABLE ENOUGH FOR A FEW THUNDERSTORMS AT
TIMES. TEMPS WILL COOL THROUGH MIDWEEK AS THE LOW MOVES OVER THE
AREA. THERE IS A 100KT SW JET STREAM ROUNDING THE BASE OF THE TROUGH
THIS MORNING...THAT WILL WEAKEN A NOTCH AND ROTATE TO NORTH TO SOUTH
ORIENTED JET ALONG THE WEST SLOPES OF THE WA AND ORE CASCADES
TONIGHT. THERE IS A SOMEWHAT DISORGANIZED FRONTAL BOUNDARY OFF THE
COAST AND CURLING INTO THE UPPER LOW JUST OFFSHORE THAT WILL BRING
AN INCREASING CHANCE OF SHOWERS TO WESTERN WA THROUGH THIS EVENING.
AT FIRST GLANCE WILL PROBABLY SEND A FORECAST OF SHOWERS LIKELY
ISOLATED EVENING THUNDERSTORMS OUT WITH THE AFTERNOON FORECAST
PACKAGE.
&&
.LONG TERM...THURSDAY WILL BE ANOTHER COOL AND SHOWERY DAY FOR
WESTERN WASHINGTON AS AN UPPER LOW OVER OREGON SHIFTS NORTHEAST AND
WRAP-AROUND EAST TO NORTHEAST FLOW ALOFT CONTINUES TO SPREAD
MOISTURE INTO THE AREA. HIGHS WILL BE SEVERAL DEGREES BELOW NORMAL
WITH THE UPPER LOW IN THE VICINITY AND PLENTY OF CLOUDS AND SHOWERS.
THE LOW WILL BEGIN TO WEAKEN AND SHIFT EAST ON FRIDAY. SHOWERS WILL
BE DECREASING ACROSS THE AREA AS THIS HAPPENS AND HIGHS WILL WARM A
FEW DEGREES. A WEAK UPPER RIDGE WILL BE OVER THE AREA NEXT WEEKEND.
THIS WILL BRING DRY WEATHER WITH HIGHS WARMING TO NEAR OR SLIGHTLY
ABOVE NORMAL. SCHNEIDER
&&
.AVIATION...AN UPPER LEVEL LOW OFFSHORE WILL KEEP SOUTHERLY FLOW
ALOFT OVER WASHINGTON THROUGH TUESDAY. THE AIR MASS WILL REMAIN
MOIST AND SOMEWHAT UNSTABLE TODAY FOR ISOLATED TO SCATTERED SHOWERS
ACROSS THE CWA...WITH A CHANCE OF THUNDERSTORMS MAINLY OVER THE
CASCADES. ASIDE FROM PATCHY LOW CLOUDS THIS MORNING...VFR CONDITIONS
ARE EXPECTED. 33
KSEA...VFR CONDITIONS WILL PREVAIL TODAY. SURFACE WINDS WILL REMAIN
SOUTHERLY 4-8KT. 33
&&
.MARINE...ONSHORE FLOW WILL CONTINUE TODAY. WIND SPEEDS MAY
APPROACH SMALL CRAFT ADVISORY RANGE IN THE CENTRAL AND EASTERN
STRAIT OF JUAN DE FUCA LATE THIS AFTERNOON AND EARLY EVENING...BUT
FOR NOW WE ARE HOLDING THE FORECAST AT 10 TO 20 KNOTS.
A WEAK LOW PRES CENTER /1012MB/ WILL SLOWLY MOVE E OVER THE OFFSHORE
WATERS THROUGH TUE...THEN WEAKEN AS IT SHIFTS INLAND TUE NIGHT. HIGH
PRES OFFSHORE AND LOW PRES OVER INTERIOR B.C. WILL MAINTAIN S/SW
FLOW ACROSS WESTERN WA THROUGH THURSDAY. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 170956
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PDT MON JUN 17 2013
.SYNOPSIS...AN UPPER LOW OFFSHORE WILL GRADUALLY SHIFT EAST DURING
THE NEXT SEVERAL DAYS...MOVING INLAND ON WEDNESDAY. THE CHANCE FOR
SHOWERS WILL GRADUALLY INCREASE EACH DAY AS THE LOW APPROACHES.
WEDNESDAY AND THURSDAY WILL PROBABLY BE THE WETTEST DAYS AS THE LOW
MOVES OVERHEAD. THERE WILL ALSO BE A GRADUAL COOLING TREND OVER THE
NEXT SEVERAL DAYS AS THE LOW MOVES ONSHORE.
&&
.SHORT TERM...AN UPPER LOW CURRENTLY AROUND 135W WILL MOVE SLOWLY
EAST TODAY AND TUESDAY. MOIST AND UNSTABLE SOUTHERLY FLOW ALOFT
AHEAD OF THE LOW WILL BRING ISOLATED TO SCATTERED SHOWERS TO THE
AREA...MAINLY AFTERNOON AND EVENING HOURS EACH DAY. THERE WILL ALSO
BE A CHANCE THUNDERSTORMS EACH DAY...PRIMARILY OVER THE CASCADES IN
THE AFTERNOON AND EVENING WHERE THE AIR WILL BE MOST UNSTABLE. HIGH
TEMPERATURES WILL BE A COUPLE DEGREES COOLER TODAY...BUT STILL A FEW
DEGREES ABOVE NORMAL...THEN COOL TO NEAR NORMAL ON TUESDAY AS THE
LOW NEARS. THE UPPER LOW WILL PUSH ONSHORE OVER OREGON ON WEDNESDAY.
EAST OR SOUTHEAST WRAP-AROUND MOISTURE WILL CONTINUE TO BRING
SHOWERS TO THE AREA WITH THE HIGHEST CHANCES OVER THE EASTERN HALF
OF THE FORECAST AREA. HIGHS WILL COOL TO A FEW DEGREES BELOW NORMAL
ON WEDNESDAY WITH THE UPPER LOW ALMOST OVERHEAD. SCHNEIDER
&&
.LONG TERM...THURSDAY WILL BE ANOTHER COOL AND SHOWERY DAY FOR
WESTERN WASHINGTON AS AN UPPER LOW OVER OREGON SHIFTS NORTHEAST AND
WRAP-AROUND EAST TO NORTHEAST FLOW ALOFT CONTINUES TO SPREAD
MOISTURE INTO THE AREA. HIGHS WILL BE SEVERAL DEGREES BELOW NORMAL
WITH THE UPPER LOW IN THE VICINITY AND PLENTY OF CLOUDS AND SHOWERS.
THE LOW WILL BEGIN TO WEAKEN AND SHIFT EAST ON FRIDAY. SHOWERS WILL
BE DECREASING ACROSS THE AREA AS THIS HAPPENS AND HIGHS WILL WARM A
FEW DEGREES. A WEAK UPPER RIDGE WILL BE OVER THE AREA NEXT WEEKEND.
THIS WILL BRING DRY WEATHER WITH HIGHS WARMING TO NEAR OR SLIGHTLY
ABOVE NORMAL. SCHNEIDER
&&
.AVIATION...AN UPPER LEVEL LOW WELL OFFSHORE WILL KEEP SOUTHERLY
FLOW ALOFT OVER WASHINGTON THROUGH TUESDAY. VFR CONDITIONS WILL
PREVAIL THIS MORNING WITH THE BKN-OVC CLOUD DECK AROUND 4-5K FEET.
WEAK ONSHORE FLOW AT THE LOW LEVELS WILL KEEP A CHANCE FOR LOW LEVEL
STRATUS CLOUDS TO FORM THIS MORNING AND A FEW HOURS OF IFR TO MVFR
CONDITIONS ARE POSSIBLE. THE AIR MASS WILL REMAIN MOIST AND SOMEWHAT
UNSTABLE TODAY FOR ISOLATED TO SCATTERED SHOWERS ACROSS THE CWA. 13
KSEA...VFR CONDITIONS SHOULD PREVAIL THIS MORNING. LOW LEVEL CLOUDS
MAY STILL DEVELOP FOR A FEW HOURS THIS MORNING WITH POSSIBLE CIGS
AROUND 1K. ANY LOW LEVEL CIGS SHOULD DISSIPATE BY EARLY AFTERNOON. 13
&&
.MARINE...WEAK ONSHORE FLOW WILL CONTINUE TODAY. WIND SPEEDS MAY
APPROACH SMALL CRAFT ADVISORY RANGE IN THE CENTRAL AND EASTERN
STRAIT OF JUAN DE FUCA LATE THIS AFTERNOON AND EARLY EVENING...BUT
FOR NOW WE ARE HOLDING THE FORECAST AT 10 TO 20 KNOTS.
A WEAK LOW PRES CENTER /1012MB/ WILL MOVE SLOWLY NE OVER THE
OFFSHORE WATERS THROUGH TUE...THEN WEAKEN AS IT SHIFTS INLAND TUE
NIGHT. HIGH PRES OFFSHORE AND LOW PRES OVER INTERIOR B.C. WILL
MAINTAIN S/SW FLOW ACROSS WESTERN WA THROUGH THURSDAY. 13
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 170353
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT SUN JUN 16 2013
.SYNOPSIS...AN UPPER LEVEL LOW OFFSHORE WILL GRADUALLY SHIFT EAST
DURING THE NEXT SEVERAL DAYS...MOVING INLAND ON WEDNESDAY. THE
CHANCE FOR SHOWERS WILL GRADUALLY INCREASE EACH DAY AS THE LOW
APPROACHES. WEDNESDAY AND THURSDAY WILL PROBABLY BE THE WETTEST DAYS
AS THE LOW MOVES OVERHEAD. THERE WILL ALSO BE A GRADUAL COOLING
TREND OVER THE NEXT SEVERAL DAYS AS THE LOW MOVES ONSHORE.
&&
.SHORT TERM...SOME PRETTY VIGOROUS THUNDERSTORMS DEVELOPED IN THE
CENTRAL CASCADES EARLIER THIS EVENING AND STAYED INTACT AS THEY
MOVED NORTH INTO CANADA. RADAR SHOWS THE LAST OF THEM EXITING THE
STATE AROUND 830 PM. A SPOTTER IN MARBLEMOUNT REPORTED 0.83 INCH OF
RAIN IN ONE HOUR. THERE WERE NUMEROUS LIGHTNING STRIKES AROUND THE
CASCADE CREST BUT ONLY ISOLATED STRIKES OVER THE EAST PUGET SOUND
LOWLANDS. IN GENERAL THERE WERE SCATTERED SHOWERS OVER MOST OF
WESTERN WASHINGTON BETWEEN 23Z AND 02Z BUT THESE ARE NOW TAPERING.
ALREADY UPDATED THE GRIDS AND ZONES.
FORECAST REMAINS ON TRACK WITH UPPER LEVEL LOW SLOWLY APPROACHING
THE COAST. THIS WILL BRING INCREASING CLOUDS AND SHOWERS WITH POPS
RANGING BETWEEN CHANCE AND LIKELY THROUGH THURSDAY. TEMPERATURES
WILL FALL INTO MAINLY THE 60S BY TUESDAY AS HEIGHTS FALL. BURKE
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
.LONG TERM...PREVIOUS DISCUSSION...THE UPPER LEVEL LOW CURVES NE TO
OVER E WA WEDNESDAY NIGHT AND THURSDAY. THIS WILL PUT W WA UNDER NE
RETURN FLOW AROUND THE LOW. BOTH THE GFS AND ECMWF SHOW A LOT MORE
QPF OVER THE AREA WITH THE HIGHEST AMOUNTS OVER THE N AND TAPERING
OFF TO THE S. THIS MAY END UP BEING THE WETTEST PERIOD THIS WEEK.
POPS WERE BOOSTED INTO THE LIKELY RANGE.
THE UPPER LEVEL LOW WANDERS UP OVER SE B.C. ON FRIDAY AND THEN
FINALLY HEADS FARTHER EAST ON SATURDAY. SHOULD SEE SHOWERS TAPERING
OFF...AND WITH A WEAK UPPER LEVEL RIDGE APPROACHING FROM THE W
SATURDAY AND SUNDAY MAY END UP BEING DRY. MAX TEMPS WILL REBOUND
BACK INTO THE 70S. KAM
&&
.AVIATION...AN UPPER LEVEL DISTURBANCE HAS TRIGGERED HIGH-BASED
SHOWERS AND THUNDERSTORMS THIS EVENING...MOST OF THE SHOWERS HAVE
MOVED NORTH INTO CANADA BY 03Z. THE FLOW ALOFT IS SOUTHERLY.
ISOLATED SHOWERS OVER THE LOWLANDS WILL DIMINISH AFTER SUNSET THIS
EVENING. VFR CONDITIONS WILL PREVAIL THIS EVENING. ONSHORE FLOW WILL
INCREASE OVERNIGHT WITH LOW LEVEL STRATUS CLOUDS PUSHING
INLAND...EXPECT A FEW HOURS OF IFR TO MVFR CONDITIONS MON MORNING.
THE AIR MASS WILL REMAIN MOIST AND SOMEWHAT UNSTABLE ON MON FOR
ISOLATED TO SCATTERED SHOWERS ACROSS THE CWA. 13/33
KSEA...VFR CONDITIONS WILL PREVAIL THIS EVENING. THE SURFACE FLOW
WILL REMAIN S/SW 5-10KT. LOW LEVEL CLOUDS WILL PROBABLY DEVELOP
OVERNIGHT FOR MVFR CEILINGS. 13/33
&&
.MARINE...ONSHORE FLOW WILL STRENGTHEN ACROSS WESTERN WA TONIGHT AS
HIGH PRES BUILDS OVER THE COASTAL WATERS. WIND SPEEDS ARE WITHIN
SMALL CRAFT ADVISORY RANGE IN THE CENTRAL AND EASTERN STRAIT OF JUAN
DE FUCA. THE CENTRAL/EAST STRAIT MAY STILL SEE A BRIEF GALE THIS
EVENING...BUT IT WON`T LAST LONG IF IT DOES. ELSEWHERE...WINDS ARE
GENERALLY S/SW IN THE 10-20 KT RANGE.
EXPECT LIGHT ONSHORE FLOW ON MONDAY. A WEAK LOW PRES CENTER /1012MB/
WILL SPIN OVER THE OFFSHORE WATERS MON NIGHT AND TUE...THEN WEAKEN
AS IT SHIFTS INLAND TUE NIGHT. HIGH PRES OFFSHORE AND LOW PRES OVER
INTERIOR B.C. WILL MAINTAIN S/SW FLOW ACROSS WESTERN WA WED THROUGH
THE END OF THE WEEK. 13/33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
&&
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 162146
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
246 PM PDT SUN JUN 16 2013
.SYNOPSIS...AN UPPER LEVEL LOW OFFSHORE WILL GRADUALLY SHIFT EAST
DURING THE NEXT SEVERAL DAYS...MOVING INLAND ON WEDNESDAY. THE
CHANCE FOR SHOWERS WILL GRADUALLY INCREASE EACH DAY AS THE LOW
APPROACHES WITH WEDNESDAY AND THURSDAY PROBABLY THE WETTEST DAYS AS
THE LOW MOVES OVERHEAD. THERE WILL ALSO BE A GRADUAL COOLING TREND
OVER THE NEXT SEVERAL DAYS AS THE LOW MOVES ONSHORE.
&&
.SHORT TERM...SOMEWHAT MOIST AND UNSTABLE S FLOW ALOFT CONTINUES
OVER W WA THIS AFTERNOON...CAUSED BY THE LARGE UPPER LEVEL LOW OUT
NEAR 45N/139W. SATELLITE IMAGERY SHOWS BUILD-UPS STARTING TO DEVELOP
OVER THE CENTRAL CASCADES AS OF 1 PM. CONVECTION WILL BE HIGH-BASED
THE REST OF THIS AFTERNOON AND EVENING AND MAINLY OVER THE CASCADES.
SOME SHOWERS COULD DRIFT OFF OF THE OLYMPICS BUT THE LOWER AIR MASS
REMAINS DRY SO ONLY SPRINKLES SHOULD RESULT.
ONSHORE PRESSURE GRADIENTS ARE INCREASING...AND A SW MARINE PUSH
WILL DEVELOP TONIGHT. PER THE NAM BOUNDARY LAYER RH THE RESULTING
STRATUS SHOULD COVER MOST OF THE W WA LOWLANDS MONDAY MORNING.
LATEST NAM BUFR SOUNDINGS SHOW A LITTLE HIGHER INVERSION MONDAY
MORNING SO THE STRATUS WILL PROBABLY END UP IN THE MVFR RANGE. THE
STRATUS WILL BREAK BY EARLY TO MID AFTERNOON...BUT THERE MAY STILL
BE ENOUGH CLOUD COVER AROUND TO ONLY MAKE IT PARTLY SUNNY. BOTH THE
GFS AND NAM NOW BRING ANOTHER SHORTWAVE TROUGH AROUND THE MAIN LOW
AND ACROSS SW WA MONDAY AFTERNOON. I WILL KEEP IT DRY MONDAY MORNING
BUT SHOW A CHANCE OF SHOWERS IN THE AFTERNOON.
THE UPPER LEVEL LOW WILL HAVE MOVED E TO AROUND 45N/130W TUESDAY
MORNING THEN MOVES SE OVER THE CENTRAL OREGON COAST WEDNESDAY
MORNING. I WILL KEEP THE BROADBRUSH CHANCE OF SHOWERS FOR BOTH DAYS
AND COOL MAX TEMPS A LITTLE MORE WITH THE LOW MOVING OVERHEAD. THE
AIR MASS MAY BE A LITTLE MORE UNSTABLE WITH THE LOW RIGHT OFFSHORE
TUESDAY AFTERNOON AND EVENING...SO THE CHANCE OF CASCADE
THUNDERSTORMS WAS RETAINED. KAM
.LONG TERM...THE UPPER LEVEL LOW CURVES NE TO OVER E WA WEDNESDAY
NIGHT AND THURSDAY. THIS WILL PUT W WA UNDER NE RETURN FLOW AROUND
THE LOW. BOTH THE GFS AND ECMWF SHOW A LOT MORE QPF OVER THE AREA
WITH THE HIGHEST AMOUNTS OVER THE N AND TAPERING OFF TO THE S. THIS
MAY END UP BEING THE WETTEST PERIOD THIS WEEK. POPS WERE BOOSTED
INTO THE LIKELY RANGE.
THE UPPER LEVEL LOW WANDERS UP OVER SE B.C. ON FRIDAY AND THEN
FINALLY HEADS FARTHER EAST ON SATURDAY. SHOULD SEE SHOWERS TAPERING
OFF...AND WITH A WEAK UPPER LEVEL RIDGE APPROACHING FROM THE W
SATURDAY AND SUNDAY MAY END UP BEING DRY. MAX TEMPS WILL REBOUND
BACK INTO THE 70S. KAM
&&
.AVIATION...AN UPPER LEVEL DISTURBANCE WILL TRIGGER HIGH-BASED
SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON AND EVENING...MAINLY
AFFECTING THE MOUNTAINS. THE FLOW ALOFT IS SOUTHERLY. SHOWERS WILL
WEAKEN/DIMINISH AFTER SUNSET THIS EVENING. VFR CONDITIONS WILL
PREVAIL THIS EVENING. ONSHORE FLOW WILL INCREASE OVERNIGHT WITH LOW
LEVEL STRATUS CLOUDS PUSHING INLAND...EXPECT A FEW HOURS OF IFR TO
MVFR CONDITIONS MON MORNING. THE AIR MASS WILL REMAIN MOIST AND
SOMEWHAT UNSTABLE ON MON FOR ISOLATED TO SCATTERED SHOWERS ACROSS
THE CWA. 33
KSEA...VFR CONDITIONS WILL PREVAIL THIS EVENING WITH
SHOWERS/CONVECTION MAINLY OVER THE MOUNTAINS. THE SURFACE FLOW WILL
REMAIN S/SW 5-10KT. LOW LEVEL CLOUDS MAY DEVELOP OVERNIGHT FOR MVFR
CEILINGS. 33
&&
.MARINE...ONSHORE FLOW WILL STRENGTHEN ACROSS WESTERN WA TONIGHT AS
HIGH PRES BUILDS OVER THE COASTAL WATERS. WIND SPEEDS ARE ALREADY
WITHIN SMALL CRAFT ADVISORY RANGE IN THE CENTRAL STRAIT OF JUAN DE
FUCA. THE CENTRAL/EAST STRAIT MAY SEE BRIEF GALES THIS EVENING AS
THE PRES GRADIENT TIGHTENS FURTHER /WHILE A SURFACE TROUGH MOVES
INLAND/. ADMIRALTY INLET WILL ALSO SEE INCREASING N/NW WINDS THIS
EVENING...A SMALL CRAFT ADVISORY REMAINS IN EFFECT.
ELSEWHERE...WINDS ARE GENERALLY S/SW IN THE 10-20 KT RANGE.
EXPECT LIGHT ONSHORE FLOW ON MONDAY. A WEAK LOW PRES CENTER /1012MB/
WILL SPIN OVER THE OFFSHORE WATERS MON NIGHT AND TUE...THEN WEAKEN
AS IT SHIFTS INLAND TUE NIGHT. HIGH PRES OFFSHORE AND LOW PRES OVER
INTERIOR B.C. WILL MAINTAIN S/SW FLOW ACROSS WESTERN WA WED THROUGH
THE END OF THE WEEK. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL STRAIT OF JUAN DE
FUCA...EASTERN STRAIT...ADMIRALTY INLET.
&&
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 161605
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
905 AM PDT SUN JUN 16 2013
.SYNOPSIS...AN UPPER LEVEL LOW OFFSHORE WILL GRADUALLY SHIFT EAST
DURING THE NEXT SEVERAL DAYS...MOVING INLAND ON WEDNESDAY. THE
CHANCE FOR SHOWERS WILL GRADUALLY INCREASE EACH DAY AS THE LOW
APPROACHES WITH WEDNESDAY AND THURSDAY PROBABLY THE WETTEST DAYS AS
THE LOW MOVES OVERHEAD. THERE WILL ALSO BE A GRADUAL COOLING TREND
OVER THE NEXT SEVERAL DAYS AS THE LOW MOVES ONSHORE.
&&
.SHORT TERM...SOMEWHAT MOIST AND UNSTABLE S FLOW ALOFT HAS BEEN
ESTABLISHED OVER W WA TODAY FROM THE LARGE UPPER LEVEL LOW NEAR
45N/139W THIS MORNING. SATELLITE IMAGERY AND OBS SHOW LOTS OF MID
AND HIGH LEVEL MOISTURE MOVING N ACROSS THE AREA...SOME OF IT LUMPY
LOOKING ACCAS. RADAR IS ALREADY PICKING UP VIRGA. THE FORECAST FOR
CONVECTION OVER THE MOUNTAINS TODAY LOOKS ON TRACK. THE NAM BUFR
SOUNDING FOR KSEA SHOWS A NICE LAYER OF INSTABILITY ALOFT ABOVE 700
MB OR 10000 FEET WHERE THE FORECAST SOUNDING LAPSE RATE IS ACTUALLY
STEEPER THAN THE MOIST ADIABATIC LAPSE RATE. LARGE SCALE FORCING IS
ALSO PRESENT IN THE FORM OF A WEAK SHORTWAVE TROUGH NEAR THE OREGON
COAST THIS MORNING THAT THE MODELS BRING UP OVER W WA THIS
AFTERNOON. A 90 KT JET STREAK WILL ALSO BE PUSHING NE ACROSS OREGON
LATE THIS AFTERNOON...PUTTING THE LEFT EXIT REGION OVER W WA. WEAK
DIFFLUENCE ALOFT IS ALSO PRESENT OVER THE CASCADES. NAM LIFTED
INDICES ARE IN THE -2 TO -4 RANGE OVER THE MOUNTAINS THIS AFTERNOON.
INSTABILITY ALOFT WILL BE PRESENT OVER ALL OF W WA THROUGH THIS
EVENING...BUT WITH ADDED SURFACE BASED INSTABILITY THE MOUNTAINS
HAVE THE GREATEST CHANCE OF SHOWERS AND PROBABLY THE ONLY CHANCE OF
THUNDERSTORMS. THAT DOES NOT PRECLUDE SOME LIGHT SPRINKLES REACHING
THE GROUND OVER THE LOWLANDS. A CHANCE OF SHOWERS AND THUNDERSTORMS
HAS BEEN ADDED TO THE OLYMPICS THIS AFTERNOON AND THIS EVENING.
SW ONSHORE FLOW LAST NIGHT BROUGHT STRATUS TO THE COAST WITH PATCHY
STRATUS OVER THE SW INTERIOR AND PARTS OF SOUTHERN PUGET SOUND.
MODELS STILL SHOW STRONGER SW ONSHORE FLOW DEVELOPING AGAIN TONIGHT
WHICH SHOULD MAKE STRATUS MORE EXTENSIVE OVER THE LOWLANDS MONDAY
MORNING. NAM BUFR SOUNDING SHOW A LOW LEVEL INVERSION DUE TO THE
WARM AIR ALOFT OVER THE AREA...SO THE STRATUS WILL BE SHALLOW.
BURN-OFF IS EXPECTED MONDAY AFTERNOON...BUT THE PRESENCE OF SOME
HIGHER CLOUD LAYERS MAY DELAY THE CLEARING SOME.
THE FORECAST IS ON TRACK FOR A CHANCE OF SHOWERS ON MONDAY AS
ANOTHER SHORTWAVE TROUGH ROTATING AROUND THE MAIN OFFSHORE LOW
APPROACHES THE AREA MONDAY AFTERNOON. THE CHANCE OF SHOWERS IN THE
FORECAST LOOKS ABOUT RIGHT FOR NOW. SHOWER ACTIVITY WILL INCREASE
AND MAX TEMPS WILL COOL AS THE LOW NEARS THE AREA ON TUESDAY. KAM
.LONG TERM...PREVIOUS DISCUSSION FROM THE 305 AM AFD...AN UPPER LOW
OVER WASHINGTON AND OREGON ON WEDNESDAY WILL PUSH SLOWLY INLAND
THURSDAY AND FRIDAY. THE WEATHER WILL BE SHOWERY AND COOL WEDNESDAY
AND THURSDAY WITH DRYING ON FRIDAY AS WEAK HIGH PRESSURE BUILDS OVER
THE AREA. A MODEST UPPER RIDGE WILL BE OVER WESTERN WASHINGTON ON
SATURDAY FOR A DRY DAY WITH HIGHS WARMING BACK TO NEAR NORMAL.
SCHNEIDER
&&
.AVIATION...AN UPPER LEVEL LOW WILL SPIN OFFSHORE TODAY WITH
SOUTHERLY FLOW ALOFT. WATER VAPOR IMAGERY SHOWS A VORTICITY MAX OFF
THE ORE COAST THAT WILL CLIP THROUGH WESTERN WA THIS AFTERNOON. THIS
DISTURBANCE WILL LIKELY TRIGGER SOME HIGH-BASED SHOWERS AND
THUNDERSTORMS...MAINLY OVER THE MOUNTAINS. SHOWERS WILL
WEAKEN/DIMINISH AFTER SUNSET THIS EVENING. VFR CONDITIONS ARE
EXPECTED ACROSS THE REGION TODAY...ASIDE FROM SOME PATCHY LOW CLOUDS
AROUND PUGET SOUND THIS MORNING. ONSHORE FLOW WILL INCREASE
OVERNIGHT WITH LOW LEVEL STRATUS CLOUDS PUSHING INLAND.
KSEA...VFR CONDITIONS WILL PREVAIL TODAY. SURFACE WINDS SW TO 10KT.
CONVECTION MAINLY OVER THE MOUNTAINS TODAY. 33
&&
.MARINE...ONSHORE FLOW WILL STRENGTHEN ACROSS WESTERN WA TODAY AS
HIGH PRES BUILDS OVER THE COASTAL WATERS. WIND SPEEDS ARE ALREADY
WITHIN SMALL CRAFT ADVISORY RANGE IN THE CENTRAL STRAIT OF JUAN DE
FUCA. THE CENTRAL/EAST STRAIT MAY SEE BRIEF GALES THIS EVENING AS
THE PRES GRADIENT TIGHTENS FURTHER /WHILE A SURFACE TROUGH MOVES
INLAND/. ADMIRALTY INLET WILL ALSO SEE INCREASING N/NW WINDS
TONIGHT...A SMALL CRAFT ADVISORY REMAINS IN EFFECT.
ELSEWHERE...WINDS ARE GENERALLY S/SW IN THE 5-15 KT RANGE.
ONSHORE FLOW WILL CONTINUE ON MON WITH HIGHEST WINDS THROUGH THE
STRAIT. A WEAK LOW PRES CENTER /1012MB/ WILL SPIN OVER THE OFFSHORE
WATERS MON NIGHT AND TUE...THEN WEAKEN AS IT SHIFTS INLAND TUE
NIGHT. HIGH PRES OFFSHORE AND LOW PRES OVER INTERIOR B.C. WILL
MAINTAIN S/SW FLOW ACROSS WESTERN WA WED THROUGH THE END OF THE
WEEK. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL STRAIT OF JUAN DE
FUCA...EASTERN STRAIT...ADMIRALTY INLET.
&&
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
| 
