000
FXUS66 KPQR 220351
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
850 PM PDT TUE MAY 21 2013

.SYNOPSIS...A COLD UPPER LOW WILL REMAIN ANCHORED OVER THE
PACIFIC NW FOR THE REMAINDER OF THE WEEK...KEEPING A COOL SHOWERY
WEATHER PATTERN IN PLACE FOR THE NEXT FEW DAYS. THE LOW WILL WEAKEN
OVER THE WEEKEND...REDUCING THE CHANCES FOR SHOWERS...AND ALLOWING
TEMPS TO WARM BACK CLOSER TO NORMAL.

&&

.SHORT TERM...SATELLITE IMAGERY SHOW UPPER LEVEL LOW ANCHORED OVER
THE PACNW WITH A COUPLE SHORTWAVES PIN-WHEELING AROUND THE LOW
CENTER. THIS PATTERN WILL CONTINUE TO FAVOR HIGH POPS AND SHOWERS
WITH PERIODIC SHORT BURSTS OF LOCALLY HEAVY RAIN. LOW FREEZING
LEVELS ALSO SUPPORT SMALL HAIL POTENTIAL WITH THE SHOWERS. SNOW
LEVELS WILL REMAIN AROUND 3KFT AGAIN TOMORROW..THEN BEGIN TO RISE A
TAD THU AND AGAIN FRI GETTING UP AROUND 5KFT BY THE START OF THE
HOLIDAY WEEKEND. WEBCAMS THIS EVENING SHOWED AN INCH OR TWO OF SNOW
IN THE PASSES ALONG THE SIDE OF THE ROAD. BUFR SOUNDINGS DO SHOW SOME
INSTABILITY WED AFTERNOON/EVE IN THE WILLAMETTE VALLEY...BUT NOT
ENOUGH CONFIDENCE TO ADD THUNDER TO FCST AT THIS TIME. WILL LET MID
SHIFT FURTHER EVALUATE.

POPS DECREASE LATE WED NIGHT AND THU AS MODELS SUGGEST THE
POSSIBILITY OF DRIER AIR WORKING IN UNDER THE LOW AS THE MAIN LOW
CENTER ROTATES UP THROUGH NORTHERN WA. WHILE THE DETAILS ARE
QUESTIONABLE AT THIS POINT...WILL SHOW A LITTLE BETTER CHANCE
FOR SHOWERS AGAIN FRI AS THE UPPER LOW SWINGS BACK AROUND THROUGH
OREGON. TEMPS ARE LIKELY TO BE AT THEIR COOLEST WED WITH A DEEP
CLOUD LAYER AND ONSHORE FLOW. TW

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY EVENING
THROUGH MONDAY...SEVERAL SHORTWAVE SYSTEMS ROTATE THROUGH A BROAD
UPPER LEVEL LOW OVER THE NORTHEAST PACIFIC AND WEST COAST. THE UPPER
LOW LINGERS ACROSS THE REGION THROUGH THIS WEEK AND INTO THE
WEEKEND...KEEPING PERIODS OF SHOWERS MIXED WITH SPORADIC SUN BREAKS
IN THE FORECAST. SNOW LEVELS RISE ABOVE CASCADE PASS LEVEL AND
TEMPERATURES WARM UP CLOSER TO NORMAL TOWARD THE BEGINNING OF NEXT
WEEK...THOUGH WET AND UNSETTLED WEATHER APPEARS TO CONTINUE THROUGH
EARLY NEXT WEEK.
KWELSON

&&

.AVIATION...SCATTERED SHOWERS CONTINUE TONIGHT WITH PRIMARILY VFR
CONDITIONS WITH ONLY AN OCCASIONAL BRIEF DIP INTO THE MVFR
CATEGORY. LIFT AHEAD OF THE NEXT LOW PRESSURE DROPPING DOWN THE
COAST SHOULD PRODUCE WIDESPREAD MVFR CIGS ACROSS THE REGION LATE
TONIGHT INTO WEDNESDAY MORNING...WITH TREND TO VFR WED AFTERNOON.

KPDX AND APPROACHES...PRIMARILY VFR TONIGHT IN SHOWERS...THOUGH
TEMPORARY MVFR CONDITIONS CAN BE EXPECTED. INCREASING CHANCES FOR
MVFR CIGS AROUND 2500 FT AFTER 10Z WED...THEN BECOMING MORE LIKELY
AFTER ABOUT 15Z AS AN AREA OF LIGHT RAIN SPREADS INTO THE REGION FROM
THE WEST. /NEUMAN

&&

.MARINE...EXPECT PERIODS OF 15 TO 20 KT WINDS WITH GUSTS UP TO 30
KT...MAINLY TIED TO SHOWERS THROUGH WEDNESDAY. THERE MAY SOME
DISTINCT LULLS IN THE WINDS...PARTICULARLY BETWEEN SHOWERS AND NORTH
OF THE COLUMBIA RIVER...BUT TIMING THESE DETAILS REMAINS UNCERTAIN
ENOUGH TO NOT INCLUDE A PARTICULAR AREA.  THE TREND WILL BE TOWARD
MORE BENIGN WEATHER LATE THIS WEEK INTO NEXT WEEKEND AS THE UPPER LOW
WEAKENS AND HIGHER SURFACE PRESSURE BUILDS INTO THE WATERS.

HIGHER CONFIDENCE THAT SEAS SHOULD GENERALLY HOVER IN THE 10 TO
12 FT RANGE FOR THE NEXT 24 HOURS BEFORE GRADUALLY SUBSIDING
THURSDAY THROUGH THE WEEKEND. /NEUMAN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT WEDNESDAY FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT WEDNESDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60
     NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
     5 PM PDT WEDNESDAY.

&&

$$

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.