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000
FXUS66 KPQR 160356
AFDPQR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
855 PM PDT WED MAY 15 2013

.SYNOPSIS...A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE THROUGH
THE PACIFIC NW DURING THE LATTER HALF OF THE WEEK...KEEPING A THREAT
OF SHOWERS IN THE FORECAST THROUGH SAT. THERE MAY BE A BREAK IN
SYSTEMS SUN OR MON...THEN A COOLER SYSTEM IS EXPECTED TO DROP DOWN
INTO THE REGION AROUND TUE.
&&

.UPDATE...FOR THE EVENING...THERE IS A BLOSSOMING AREA OF CLOUDS IN
WARM AIR ADVECTION JUST OFFSHORE AND ACTIVITY EVIDENT ON KRTX RADAR
AS WELL BOTH INLAND AND OFFSHORE. MODEL FORECASTS AND WV PICTURES
INDICATE THE DEEPER MOISTURE ASSOCIATED WITH THE NEXT SET OF
SHORTWAVES REMAINS ALONG THE SOUTHERN TIER OF COUNTIES AND INTO
SOUTHERN OREGON...BUT THE HRRR INDICATES ENOUGH ACTIVITY MAKING IT
INTO THE COAST AND COAST RANGE TO WARRANT THE LIKELY POPS FOR MOST
COAST RANGE WEST...LOOKS LIKE SOME RAIN WILL SPREAD INTO THE VALLEY
TONIGHT BUT WILL NOT EVERYWHERE AS THE ECHOES LOOK FRAGMENTED AND
NOT COMPLETELY FILLED IN. THEN IT LOOKS LIKE TOMORROW WE GET
SOME DEFORMATION PRECIPITATION AND A DIURNAL INCREASE RELATED TO THE
UPPER TROUGH BEING RIGHT ON TOP OF US AND THE SHORTWAVE PASSING BY
TO THE SOUTH. HAVE RAISED POPS ACCORDINGLY FOR TOMORROW AFTERNOON.
GENERAL THEME REMAINS THE SAME MENTIONED IN THE SHORT TERM
DISCUSSION BELOW. KMD

.SHORT TERM...SATELLITE DERIVED PRECIPITABLE WATER IMAGES SHOW A
LONG FETCH OF SUBTROPICAL MOISTURE STREAMING ACROSS THE PACIFIC
TOWARDS THE CA OREGON BORDER. IN THE WESTERLY FLOW ALOFT...SEEN IN
WATER VAPOR PICTURES...MODELS DEPICT A SERIES OF SHORTWAVES MOVING
THROUGH. THE FIRST TROUGH JUST OFFSHORE...IS SLOW TO MOVE THROUGH
WITH MULTIPLE EMBEDDED SHORTWAVES AFFECTING THE AREA TONIGHT THROUGH
THU NIGHT. ANOTHER TROUGH...ORIGINATING NEAR 160W...IS FORECAST BY
GFS AND ECMWF TO REACH THE AREA DURING THE DAY SAT. WITH MOIST
ONSHORE FLOW CONTINUING THROUGH THE NEXT SEVERAL DAYS...WILL NEED TO
LEAVE IN SOME POPS THROUGHOUT THE TIME PERIOD...BUT WILL TRY TO
REFLECT ENHANCED POPS TONIGHT THROUGH THU EVENING...AND AGAIN ON SAT.

LATEST LOOK AT BUFR SOUNDINGS SUGGEST AT BEST A MINIMAL THREAT FOR
THUNDERSTORMS WITH THE SHOWERS...MOST LIKELY THU...BUT STILL
PROBABLY NOT WORTH THE MENTION AT THIS POINT. TEMPS THROUGH SAT
LIKELY TO REMAIN NEAR OR SLIGHTLY BELOW NORMAL.

.LONG TERM...SATURDAY EVENING THROUGH WEDNESDAY...THE REMNANTS OF A
FRONTAL SYSTEM WILL MOVE THROUGH THE AREA LATE THIS WEEKEND...
KEEPING THE REGION COOL...CLOUDY AND DAMP. EXPECT BRIEF RIDGING TO
DEVELOP OVER THE PACIFIC NORTHWEST MONDAY...WITH DRY CONDITIONS AND
TEMPERATURES NEAR NORMAL. THE NEXT SIGNIFICANT SYSTEM ARRIVES LATE
MONDAY NIGHT/TUESDAY...WITH SNOW LEVELS DROPPING NEAR CASCADE
PASSES. COOLER AND UNSETTLED WEATHER WILL LINGER THROUGH THE
REMAINDER OF THE WEEK. /27
&&

.AVIATION...THERE WILL BE LITTLE CHANGE IN FLIGHT CONDITIONS
TONIGHT AND THURSDAY AS A SURFACE LOW OFFSHORE WILL CONTINUE
CLOUDY CONDITIONS WITH PERIODS OF LIGHT RAIN. MOSTLY MVFR CIGS
THIS EVENING WITH LOCAL VFR TO THE FAR SOUTH. WIDESPREAD MVFR
CONDITIONS WITH SPOTTY IFR ALONG THE COAST IS EXPECTED AFTER
08Z...AS WELL AS MORE STEADY RAIN. RAIN WITH VARIABLE CIGS AND
VISIBILITIES WILL PERSIST THROUGH MUCH OF THURSDAY. WINDS WILL
WEAKEN TONIGHT AND BE GENERALLY LIGHT AND VARIABLE THURSDAY.


KPDX AND APPROACHES...MOSTLY VFR CONDITIONS FOR THE REST OF THE
EVENING. CIGS WILL LOWER AROUND 10Z WITH MIX OF VFR AND MVFR FOR MOST
OF THURSDAY.

&&

.MARINE...GUSTY WINDS ARE EASING THIS EVENING AND AM GOING TO HAVE
THE SMALL CRAFT ADVISORY FOR THE INNER WATERS EXPIRE AT 9 PM
TONIGHT. THE WINDS WILL CONTINUE TO DECREASE TONIGHT AND THURSDAY
AS A WEAK SURFACE LOW MOVES OVER THE WATERS. WEAK SURFACE PRESSURE
WILL MAINTAIN LIGHT WINDS AND LOW SEAS THROUGH FRIDAY NIGHT. THE
NEXT FRONT THAT MAY CAUSE WINDS TO INCREASE ABOVE 20 KT IS
EXPECTED SATURDAY. SEAS WILL REMAIN BELOW 7 FT THROUGH THE
WEEKEND.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.

&&

$$

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

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.