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Forecast Discussion:NW Oregon - SW Washington
217 PM PDT FRI JUL 3 2009SYNOPSIS
A STRONG UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE PACIFIC NORTHWEST INTO THE HOLIDAY WEEKEND. THIS PATTERN IS BRINGING THE WARMEST WEATHER OF THE YEAR. AN UPPER TROUGH WILL APPROACH THE AREA LATE IN THE WEEKEND FOR A SLOW COOL DOWN AS WE GO INTO NEXT WEEK. &&
SHORT TERM
VISIBLE SATELLITE IMAGERY SHOWS LOW CLOUDS AND FOG HAVE BURNED BACK TO THE BEACHES THIS AFTERNOON IN A WEAK ONSHORE FLOW. WEATHER WILL CONTINUE HOT AND DRY INLAND THROUGH THE 4TH. THE THERMAL TROUGH SHIFTED INLAND SOMEWHAT TODAY...HOWEVER THE TEMPERATURE STARTED OUT WARMER THIS MORNING GIVING US TEMPERATURESSIMILAR TO YESTERDAY. MODELS ARE ACTUALLY SHOWING A SLIGHT OFFSHORE FLOW FOR SATURDAY MORNING...SO EXPECT THE LOW CLOUDS/FOG TO BE LESS TONIGHT/SATURDAY MORNING. HEAT ADVISORY WILL REMAIN IN EFFECT. LOOKING FOR AN ONSHORE PUSH REACHING INLAND SUNDAY AFTERNOON TO BEGIN THE COOLING OVER THE AREA. MODELS CONTINUE WITH SOME INSTABILITY BY SUNDAY IN THE CASCADES. AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE THROUGH THE FORECAST AREA MONDAY GIVING AN INCREASED CHANCE OF PRECIPITATION ...MAINLY ALONG THE COAST AND TO THE CASCADES/COASTAL RANGE.
LONG TERM
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL ESTABLISH ITSELF OVER THE FORECAST AREA THE FIRST PART OF NEXT WEEK AND WILL PERSIST THROUGH THE WEEK. THIS WILL BRING COOLER TEMPERATURES AND A CHANCE OF SHOWERS. &&
AVIATION
IFR STRATUS AND FOG CONTINUES TO HUG THE COAST LINE THIS AFTERNOON. SATELLITE IMAGERY SHOWS THE STRATUS THINNING AND IT SHOULD CLEAR BACK FROM THE COAST LATER THIS AFTERNOON. CLEAR SKIES ARE EXPECTED ELSEWHERE FOR THE NEXT 24 HOURS. STRATUS AND FOG SHOULD NOT BE AS WIDESPREAD ALONG THE COAST SATURDAY MORNING WITH WEAKER ONSHORE FLOW. KPDX AND APPROACHES...NO SIGNIFICANT WEATHER IMPACTS EXPECTED. &&
MARINE
SEAS ARE NOT TOO HIGH BUT WITH SHORT PERIOD WIND WAVES SEAS CONDITIONS WILL REMAIN A LITTLE CHOPPY. LESS WIND AND CHOPPY SEAS THROUGH THE WEEKEND AS THE THERMAL TROUGH SHIFTS INLAND AND HIGH PRES OVER THE NE PACIFIC WEAKENS. &&
PQR WATCHES/WARNINGS/ADVISORIES
OR/WA...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.