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000
FXUS66 KPQR 160034 AAA
AFDPQR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
534 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.
&&

UPDATED MARINE SECTION

.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...LIGHT RAIN SHOWERS PRODUCING TEMPORARY AND PATCHY MVFR
CIGS ACROSS THE REGION SHOULD BEGIN TO WANE LATE THIS AFTERNOON WITH
CONDITIONS BECOMING PREDOMINANTLY VFR. WE MAY SEE MVFR CIGS
REDEVELOP OVERNIGHT...PARTICULARLY AFTER 09Z THURSDAY...BUT
CONFIDENCE IS LOW.

KPDX AND APPROACHES...EXPECT PREDOMINANTLY VFR CONDITIONS OVER THE
NEXT 24 HOURS AS A BROAD TROUGH HANGS OVER THE REGION. A TEMPORARY
MVFR CIG WILL BE POSSIBLE AT ANY POINT WITH THE BEST CHANCE OF
THESE LOWER CIGS OCCURRING AROUND 12Z TO 15Z THURSDAY. /NEUMAN

&&

.MARINE UPDATE...WIND GUSTS NEAR SHORE...WITHIN 10 NM...HAVE BEEN
STRONGER LATE THIS AFTERNOON THAN EXPECTED AS A WEAK FRONT MOVED
ACROSS THE WATERS...AND HAVE ISSUED A SHORT DURATION SMALL CRAFT
ADVISORY FOR THIS EVENING. THE WINDS WILL DECREASE LATER THIS
EVENING.

FROM PREVIOUS DISCUSSION...A BROAD TROUGH OF LOW PRESSURE WILL HANG
OVER THE REGION KEEPING WINDS AND SEAS LOW THROUGH THE END OF THE
WORK WEEK. THE NEXT FRONT THAT MAY CAUSE WINDS TO JUMP ABOVE 20 KT
SHOULD ARRIVE SATURDAY. SEAS LOOK TO REMAIN BELOW 10 FT INTO EARLY
NEXT WEEK.
/NEUMAN

&&

.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.