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000
FXUS66 KPQR 162116
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
216 PM PDT SUN JUN 16 2013

.SYNOPSIS...WITH AN UPPER LEVEL LOW OFFSHORE...SW FLOW INTO THE
REGION WILL BRING PROGRESSIVELY BETTER CHANCES FOR SHOWERS OVER THE
NEXT FEW DAYS. THE LOW WILL SLOWLY WORK ITS WAY CLOSER TO THE COAST
MON AND TUE...BEFORE MOVING INLAND WED. THE MAIN ENERGY WITH THE LOW
WILL MOVE EAST DURING THE LATTER PART OF THE WEEK...BUT WEAKER LOW
PRESSURE ALOFT WILL MAINTAIN ONSHORE FLOW TO KEEP NIGHT AND MORNING
CLOUDS AROUND...AND A DECREASING CHANCE OF SHOWERS.
&&

.SHORT TERM...SATELLITE SHOWS CUMULUS DEVELOPMENT EARLY THIS
AFTERNOON PRIMARILY OVER THE CASCADES AND FOOTHILLS. A SHORTWAVE
SEEN IN WATER VAPOR PICTURES ROTATING UP THROUGH SW OREGON AT MIDDAY
APPEARS POISED TO TRIGGER SOME CONVECTION LATER THIS AFTERNOON...
MAINLY OVER THE HIGH CASCADES. THE FLOW ALOFT AGAIN APPEARS TO BE
FROM THE SSW...WHICH SHOULD DRIVE ANY STORMS E OF THE CREST SIMILAR
TO YESTERDAY. MODEL ONSHORE GRADIENTS APPEAR TO BE A LITTLE WEAKER
MON MORNING COMPARED TO SUN...SO OVERALL EXPECT SOME MARINE CLOUDS
INLAND BY MORNING...BUT NOT LIKELY TO BE ANY MORE EXTENSIVE THAN
SUN.

MODEL CONSENSUS IS FOR THE UPPER LOW OFFSHORE TO DRIFT E...BUT A BIT
SLOWER THAN YESTERDAYS RUNS. THIS RESULTS IN INCREASING CHANCES FOR
SHOWERS THE NEXT FEW DAYS...PEAKING WED AS THE UPPER LOW MOVES
INLAND. MODELS ALSO TENDING TO AGREE ON A TROUGH ROTATING AROUND THE
BASE OF THE LOW TUE...RESULTING IN AS MORE SOUTHERLY FLOW OVER THE
REGION TUE WITH A BIT BETTER INSTABILITY AS SUGGESTEDIN GFS LI
FIELD. SO IN ADDITION TO INCREASING POPS NEXT FEW DAYS...WILL
MAINTAIN A SLIGHT CHANCE FOR THUNDER TUE. WITH THE INCREASED CHANCES
FOR SHOWERS...DAYTIME TEMPS WILL COOL BACK BELOW NORMALS TUE AND WED.

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...UPPER LOW CENTERED
OVER THE PAC NW WEDNESDAY NIGHT WILL SLOWLY DRIFT NORTHWARD ON
THURSDAY. BY FRIDAY THE LOW WILL BE NEAR THE CANADIAN BORDER...FOR
ONLY A SLIGHT CHANCE OF SHOWERS IN NORTHERN ZONES OF THE CWA AND
INTO WASHINGTON STATE. MUCH OF THE REGION LOOKS TO BE DRY SATURDAY
AS A WEAK RIDGE BUILDS IN. UNCERTAINTY INCREASES ON SUNDAY AS THE
MODELS ARE ADVERTISING A LARGE TROUGH SETTING UP OVER THE EASTERN
PACIFIC...LIKELY BRINGING ANOTHER ROUND OF WET WEATHER TO THE REGION
LATE SUNDAY. BURGESS
&&

.AVIATION...VARIABLE MID/HIGH CLOUDS ACROSS THE REGION THIS
AFTERNOON THROUGH TONIGHT. OVER THE CASCADES...CUMULUS BUILDUPS WILL
LEAD TO SOME SHOWERS AND ISOLATED THUNDERSTORMS THROUGH 05Z. AIR
MASS STABILIZING AFTERWARDS. MARINE STRATUS WILL REFORM ALONG THE
COAST AGAIN TONIGHT. SIMILAR TO THAT ON SUN AM...AREAS OF MVFR
CLOUDS RETURN LATE TONIGHT INTO MON AM...THOUGH NOT AS WIDESPREAD IN
COVERAGE TO DUE LIGHTER ONSHORE GRADIENT. CLOUD TOPS 2-3K FT.

KPDX AND APPROACHES...VFR CONDITIONS...WITH MOSTLY HIGH CLOUDS.
UNTIL 05Z...WATCH FOR CUMULUS BUILDUPS AND A FEW THUNDERSTORMS
OVER THE CASCADES IN THE E APPROACHES. LATER TONIGHT...SHOULD SEE
MVFR MARINE STRATUS PUSHING UP COLUMBIA RIVER...BUT SHOULD NOT BE
AS EXTENSIVE AS IT WAS SUN AM.                    ROCKEY.
&&

.MARINE...NOT MUCH CHANGE. LOW PRES PUSHING INTO THE REGION WILL
MAINTAIN RATHER LIGHT PRES GRADIENTS. WINDS REMAIN 15 KT OR LESS.
DO HAVE MIXED SWELL SET...WITH PRIMARY SWELL FROM W AT 2 TO 3
FT...BUT ALSO HAVE S SWELL ABOUT THE SAME. OVERALL SEAS RUNNING AT
3 TO 4 FT FOR NEXT SEVERAL DAYS.

HIGH PRES WILL BUILD AGAIN OVER THE NE PAC LATER THIS WEEK... WITH
A RETURN N TO NW WINDS...BUT STILL LOOKS TO BE 20 KT OR LESS.
&&

.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.