000
FXUS66 KPQR 120412
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
905 PM PDT TUE JUN 11 2013

.SYNOPSIS...AN UPPER LEVEL LOW SLOWLY PUSH ACROSS THE PAC NW THROUGH
THU...WITH COOL SHOWERY WEATHER. THEN WARMER SOMEWHAT DRIER FOR THIS
WEEKEND. HOWEVER...EXPECT INCREASING UNSETTLED WEATHER AGAIN BY LATE
SUN INTO EARLY NEXT WEEK.
&&

.SHORT TERM...UPPER LOW JUST OFF THE WASHINGTON COAST WILL DOMINATE
THE WEATHER FOR THE NEXT 2 DAYS...WITH OCCASIONAL SHOWERS AND COOLER
TEMPERATURES. SNOW LEVELS WILL HOVER BETWEEN 5500 AND 6500 FEET BUT
ANY ACCUMULATIONS LOOK TO BE MINOR...WITH TOTALS FROM NOW THROUGH THU
EVENING OF GENERALLY 1 TO 3 INCHES.

SHOWERS WILL INCREASE AGAIN BY LATE WED AM INTO WED AFTERNOON. THIS
DUE TO ANOTHER UPPER DISTURBANCE ROTATING AROUND THE UPPER LOW. AS
THIS DISTURBANCE ROTATES ACROSS THE REGION...INSTABILITY IS ENHANCED.
LOOKS GOOD FOR SHOWERS THAT WILL HAVE BRIEF DOWNPOURS AND POSSIBLY A
FEW WITH SMALL HAIL.  NOT SURE YET...BUT MODELS INDICATE SOME
POTENTIAL FOR A FEW ISOLATED TSTORMS IN THE AFTERNOON INTO THE EARLY
EVENING HOURS.

THE UPPER LOW IS PROGGED TO DROP SOUTH TOWARDS OUR CWA WED NIGHT INTO
THU...WHICH SHOULD ALLOW SHOWER ACTIVITY TO CONTINUE DURING THIS
TIME. THE LATEST MODEL RUNS HAVE THE LOW CENTER DIRECTLY OVERHEAD BY
THU MORNING...THEN PUSHING EAST DURING THE DAY. PRECIPITATION MAY BE
ENHANCED AT TIMES THU ON THE BACK SIDE OF THE LOW DUE TO A A WEAK
DEFORMATION AXIS AND/OR A SHORTWAVE ROTATING AROUND THE BACK SIDE OF
THE TROUGH. ALSO MAY NEED TO CONSIDER ADDING THUNDERSTORM POTENTIAL
FOR THU...AS THE COLDEST AIR ALOFT WILL BE OVER THE REGION DURING
THIS TIME.

SHOWERS SHOULD BEGIN TO TAPER OFF THU NIGHT INTO EARLY FRI AS THE
UPPER LOW PUSHES EAST OF THE CASCADES AND ALLOWS A BRIEF PERIOD OF
RIDGING TO PUSH IN LATER FRI. WE MAY KEEP SOME LIGHT ACTIVITY AROUND
INTO FRI MORNING DUE TO LIGHT OROGRAPHIC LIFT AND CYCLONIC FLOW
ALOFT. THEN EXPECT DRIER AND WARMER CONDITIONS TO DEVELOP FOR LATER
FRI. ROCKEYPYLE

.LONG TERM...FRIDAY EVENING THROUGH TUESDAY...WEAK RIDGING DEVELOPS
BRIEFLY OVER THE FORECAST AREA LATE FRIDAY THROUGH EARLY SATURDAY AS
AN UPPER TROUGH LOOMS NEAR THE PACIFIC NORTHWEST COAST. THIS TROUGH
WILL SWING SEVERAL DISTURBANCES ACROSS THE REGION THROUGH THE
WEEKEND...WITH THE MAIN THREAT FOR SHOWERS OVER THE MOUNTAINS.
CONVECTION OVER THE MOUNTAINS LOOKS MORE PROMISING SUNDAY AND MONDAY
AFTERNOON...AS SOUTHERLY FLOW ALOFT INCREASES. THE CENTER OF THE LOW
PUSHES INLAND EARLY NEXT WEEK...ALLOWING WIDESPREAD SHOWERS TO
INCREASE. MODELS ARE SHOWING THIS TROUGH WILL MAINTAIN UNSETTLED
WEATHER ACROSS THE REGION THROUGH LATE NEXT WEEK. /27
&&

.AVIATION...UPPER TROUGH OVER WESTERN OREGON AND WASHINGTON WILL
MOVE LITTLE THROUGH WED. THE MARINE LAYER WILL REMAIN DEEP ENOUGH TO
SUPPORT PREDOMINANTLY VFR CONDITIONS. HOWEVER...COASTAL AREAS MAY
HAVE LOCAL MVFR CIGS AFTER 10Z WED AS POTENTIAL FOR SHOWERS
INCREASE. LOCAL MVFR CIGS AROUND 2000-3000 FT MAY AFFECT INLAND
AREAS BETWEEN 12Z AND 17Z WED PROVIDED THERE IS ENOUGH CLOUD
BREAKS. SHOWERS INCREASE INLAND BY MIDDAY WED.

KPDX AND APPROACHES...MAINLY VFR CONDITIONS THROUGH WED. LOW
CHANCES FOR MVFR CIGS AROUND 2500 FT FROM ABOUT 13Z-17Z WED.
&&

.MARINE...WEAK LOW PRESSURE OFF VANCOUVER ISLAND WILL DRIFT SOUTH
INTO THE WATERS WEDNESDAY THEN MOVE ONSHORE LATER ON THURSDAY.
WINDS REMAIN GENERALLY LIGHT FOR THE WATERS THE NEXT FEW DAYS. NW
FLOW OVER THE OFFSHORE WATERS BEHIND THE LOW WILL GENERATE SOME
MODEST 5-6 FT SWELL WHICH WILL AFFECT MAINLY OUR SOUTHERN WATERS
THROUGH WED. OTHERWISE SEAS WILL GRADUALLY SUBSIDE LATER THIS
WEEK...POSSIBLY AS LOW AS 3 FT IN LIGHT WINDS BY FRIDAY. ANOTHER
UPPER LEVEL LOW WILL DEVELOP OFFSHORE THIS WEEKEND...BUT SO FAR
WINDS LOOK PRETTY LIGHT WITH THIS SYSTEM.  WEAGLE
&&

.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.