000
FXUS66 KPQR 080331
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 PM PDT SUN SEP 07 2008

.SYNOPSIS...AN UPPER RIDGE OVER THE EASTERN PACIFIC WILL BE THE
PERSISTENT LARGE SCALE FEATURE THROUGH MUCH OF THE COMING WEEK. THERE
WILL BE SOME WEAK UPPER LEVEL DISTURBANCES RIDING OVER THE RIDGE AND
DOWN INTO THE ROCKY MOUNTAIN REGION THAT WILL AFFECT THE ONSHORE FLOW
AND MARINE LAYER AT TIMES. ONE DISTURBANCE TO OUR NORTH WILL TURN THE
FLOW ONSHORE MONDAY NIGHT AND TUESDAY AS AN UPPER TROUGH CARVES OUT
OVER THE ROCKY MOUNTAIN REGION AGAIN. THE UPPER RIDGE WILL THEN
REBUILD WEDNESDAY AND THURSDAY FOR ANOTHER WARMING PERIOD BEFORE THE
NEXT DISTURBANCE RETURNS ONSHORE FLOW TO THE AREA AT THE END OF THE
WEEK.
&&

.SHORT TERM...CLEAR SKIES WILL CONTINUE OVER THE REGION TONIGHT
INCLUDING THE COASTAL WATERS...BUT THERE COULD BE SOME MINOR FOG
PATCHES NEAR THE COASTLINE TOWARD DAYBREAK MON. THE SURFACE THERMAL
TROUGH WILL REMAIN CLOSE TO THE COAST TONIGHT AND EARLY MON...FOR
ANOTHER PLEASANT WARM LATE SUMMER DAY IN THE NW. INLAND TEMPS WILL BE
CLOSE TO THOSE TODAY.

THE THERMAL TROUGH SHIFTS EAST LATE MON AND REACHES E OF THE CASCADES
MON EVENING AS A WEAK UPPER DISTURBANCE MOVES IN FROM THE NW...
TURNING THE LOW LEVEL FLOW ONSHORE AND DEVELOPING A MARINE LAYER ON
THE COAST THAT WILL PUSH INTO THE COASTAL GAPS OVERNIGHT MON NIGHT.
THE MODELS ARE SHOWING A FAIR AMOUNT OF LOW CLOUDS INLAND TUE MORNING
FOR THE VALLEYS...LOWER COAST RANGE AND FOOTHILLS...THAT WILL TAKE
SOME TIME TO BREAK UP IN THE AFTERNOON. THE CASCADES AND HIGHER COAST
RANGE PEAKS APPEAR TO REMAIN ABOVE THE CLOUDS ALTHOUGH TEMPS WILL BE
LOWER IN A COOLER AIR MASS. CLOUDS MAY PERSIST ON THE COAST AND NEAR
THE MOUNTAINS THROUGH MUCH OF THE DAY AS THE WESTERLY ONSHORE FLOW
REMAINS STRONG ALL DAY. WILL NEED TO WATCH WHETHER WE CAN GET SOME
DRIZZLE ON THE COAST EARLY TUE.

CLOUDS WILL CONTINUE TUE NIGHT AND WED MORNING...THEN CLEAR WED
AFTERNOON AS HIGHER PRESSURE BEGINS TO BUILD BACK INTO THE PAC NW. RW

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
HIGH PRESSURE BUILDS OVER THE PACIFIC NORTHWEST
WEDNESDAY NIGHT INTO THURSDAY FOR CLEARING SKIES AND SOME WARMING ON
THURSDAY. THIS WILL BE SHORT-LIVED HOWEVER AS AN UPPER LEVEL TROUGH
MOVING INTO BRITISH COLUMBIA FLATTENS THE RIDGE THURSDAY NIGHT INTO
FRIDAY. ONSHORE FLOW SHOULD RETURN FRIDAY THROUGH THE WEEKEND...FOR
CLOUDY CONDITIONS AND A RETURN TO MORE NORMAL TEMPERATURES FRIDAY AND
SATURDAY. LATEST MODEL RUNS INDICATE A REBUILDING OF THE RIDGE TO
BEGIN NEXT WEEK...WILL HAVE TO WAIT FOR FURTHER RUNS TO SOLIDIFY THIS
SOLUTION. BROWN
&&

.AVIATION...HIGH OFFSHORE EXTENDING INTO NORTHERN ROCKIES TONIGHT.
THERMAL TROUGH ALONG COAST SHIFTS OFFSHORE OVERNIGHT. THERMAL TROUGH
SHIFTS TO CENTRAL OREGON MONDAY AFTERNOON. NORTHERLY FLOW THIS
EVENING BECOMES LIGHT OFFSHORE LATER TONIGHT AND MONDAY MORNING.
NORTHWEST FLOW INCREASES MONDAY AFTERNOON AS THERMAL TROUGH SHIFTS
EAST. VFR CONDITIONS OVER ALL THE AREA TONIGHT. A FEW FOG PATCHES
ARE POSSIBLE ALONG THE COAST LATE TONIGHT AND EARLY MONDAY WITH
LOCAL IFR CONDITIONS. CONDITIONS WILL REMAIN VFR ON MONDAY.

KPDX AND APPROACHES...VFR CONDITIONS IN THE KPDX AREA TONIGHT AND
MONDAY.
&&

.MARINE...STRONG HIGH PRESSURE OFFSHORE TONIGHT AND MONDAY. THERMAL
TROUGH ALONG COAST SHIFTS OFFSHORE LATER TONIGHT. THERMAL TROUGH
SHIFTS BACK ASHORE MONDAY MORNING THEN MOVES FURTHER INLAND MONDAY
AFTERNOON. SMALL CRAFT WINDS WILL RETREAT TO THE OUTER WATERS AFTER
MIDNIGHT. SMALL CRAFT WINDS WILL GRADUALLY PUSH TO BEACHES MONDAY AS
THE THERMAL TROUGH SHIFTS EASTWARD. SEAS WILL REMAIN BELOW 10 FEET
TONIGHT AND MONDAY. HAZARDOUS SEAS DUE TO CHOPPY SEAS FROM WIND
GENERATED WAVES WILL OCCUR OVER THE CENTRAL COAST TONIGHT AND MONDAY
MORNING AND OVER ALL THE WATERS MONDAY AFTERNOON.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR/WA...SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO FLORENCE
         THROUGH MON NIGHT.
        SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CASCADE HEAD TO
         FLORENCE TONIGHT THROUGH MON NIGHT.
        SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER
         TO CASCADE HEAD MONDAY AFTERNOON AND MONDAY NIGHT.
&&

.PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION)
AST 00111-   PDX 0001--   SLE 000---   EUG 000---

$$

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.

Weather information courtesy of NOAA and AviationWeather.gov

© Willamette Aviation Service, LLC