Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 041006
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
205 AM PST WED MAR  4 2015

.SYNOPSIS...HIGH PRESSURE WILL DOMINATE THIS WEEK AND MAINTAIN A DRY
WEATHER PATTERN. DAYTIME TEMPERATURES WILL GRADUALLY WARM EACH DAY
THIS WEEK WITH VALLEY HIGH TEMPERATURES CLIMBING INTO THE 60S
THIS WEEKEND. THE UPPER RIDGE WILL WEAKEN EARLY NEXT WEEK AND A FRONT
MAY BRING RAIN TO THE REGION NEXT TUESDAY OR WEDNESDAY.
&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT...CLEAR SKIES AND RELATIVELY
CALM WINDS OVERNIGHT HAS RESULTED IN MOST INLAND TEMPERATURES TO DROP
BELOW FREEZING EARLY THIS MORNING. SOME COASTAL LOCATIONS HAVE ALSO
DROPPED TO NEAR OR AT FREEZING LIKE ASTORIA AND TILLAMOOK.

WATER VAPOR IMAGERY SHOWS AN UPPER RIDGE OF HIGH PRESSURE OVER THE
PACIFIC NW WITH THE RIDGE AXIS JUST OFFSHORE. THIS HAS RESULTED IN
DRY AIR ACROSS THE REGION WITH DEW POINT TEMPERATURES IN THE MID TO
UPPER 20S. SURFACE OBSERVATIONS AT SOME LOCATIONS ARE SHOWING THE
TEMPERATURE/DEWPOINT SPREAD BECOMING SMALLER AND THERE MAY BE LOCAL
SPOTS WITH SHALLOW FOG BY SUNRISE, BUT MOST LOCATIONS WILL REMAIN
CLEAR. TEMPERATURES THIS AFTERNOON WILL BE SLIGHTLY WARMER THAN THEY
WERE ON TUESDAY.

THERE WILL BE LITTLE CHANGE IN THE WEATHER TONIGHT AND THURSDAY AS
HIGH PRESSURE HOLDS OVER THE AREA. AN UPPER LEVEL TROUGH WILL MOVE
OVER WESTERN CANADA THURSDAY EVENING AND FLATTEN THE UPPER RIDGE.
THERE MAY BE AN INCREASE OF HIGH CLOUDS WITH THE TROUGH...BUT THESE
WILL HAVE LITTLE IMPACT TO THE WEATHER.

A WEAK SURFACE LOW OFFSHORE OF SOUTHERN OREGON WILL RESULT IN A WIND
REVERSAL FOR THE COAST FRIDAY. SOUTHERLY WINDS ARE EXPECTED NEAR
FLORENCE AND NEW PORT EARLY FRIDAY MORNING...REACHING TILLAMOOK
AROUND NOON. THE SOUTHERLY WINDS WILL INCREASE SURFACE MOISTURE AND
LIKELY BRING STRATUS/FOG TO THE IMMEDIATE COAST. THE TEMPERATURES FOR
THE COAST WILL NOT LIKELY BE WARMER FRIDAY...IN FACT THEY MAY BE A
FEW DEGREES COOLER.

WEAK ONSHORE WINDS FRIDAY NIGHT MAY BRING THE MOISTER AND COOLER
COASTAL AIR FURTHER INLAND. HOWEVER...A SUBSIDENCE INVERSION FROM THE
UPPER RIDGE SHOULD LIMIT HOW FAR INLAND THE STRATUS WILL GO, BUT
EXPECT THE INCREASE OF INLAND LOW LEVEL MOISTURE TO RESULT IN MORE
WIDESPREAD FOG INLAND. ANY FOG SHOULD BE SHALLOW AND BURN OFF QUICKLY
SATURDAY. TJ

.LONG TERM...SATURDAY THROUGH TUESDAY...THE UPPER RIDGE WILL
GRADUALLY SHIFT FROM BEING CENTERED NEAR 130W LATE THIS WEEK TO THEN
EXPAND EASTWARD ACROSS THE WESTERN CONUS THROUGH EARLY NEXT WEEK.
MAIN CHANGE WAS TO BUMP TEMPERATURES UP ANOTHER COUPLE DEGREES FOR
THE WEEKEND BRINGING MOST VALLEY LOCATIONS INTO THE MID 60S AND THE
COASTAL AREAS TO THE UPPER 50S TO LOWER 60S. NOT MUCH SURFACE
PRESSURE GRADIENT TO SPEAK OF OR ELSE WE COULD HAVE EASILY HIT THE
MAGICAL 70 DEGREE MARK IF WE HAD OFFSHORE FLOW. AS THE UPPER RIDGE
EXPANDS EASTWARD MONDAY...MODELS ARE SHOWING A SOMEWHAT AGGRESSIVE
TROUGH SWING SOUTH FROM ALASKA AND DRAG A CUTOFF LOW OUT TOWARD 150W
TOWARD THE PACNW COAST. HAVE DELAYED ANY MENTION OF RAIN UNTIL
TUESDAY AS MEDIUM RANGE MODELS ARE IN MODEST AGREEMENT IN BRINGING
THE FILLING UPPER LOW CLOSE ENOUGH TO THE COAST TO SPREAD RAIN WELL
INLAND TUESDAY NIGHT. AM SOMEWHAT SKEPTICAL THIS WILL FULLY COME TO
FRUITION AS THE MODELS INDICATE AS WE HAVE SEEN THIS TIME AND AGAIN
THIS WINTER AT THAT TIME RANGE. THIS ONE IS A LITTLE DIFFERENT,
HOWEVER, AS THE EASTERN HALF OF THE CONUS APPEARS TO BE LOSING ITS
SEMI-PERSISTENT TROUGH WHICH COULD OPEN THE DOOR AS ADVERTISED.
ANOTHER FACTOR IS THE TIMING OF THE ALASKA TROUGH. IF IT`S MUCH
FASTER OR SLOWER AT SWINGING ACROSS THE NORTH THEN THE TIMING WILL
BE OFF AND IT MAY NOT GATHER THE CUTOFF LOW AND LEAVE IT WELL
OFFSHORE. /JBONK
&&

.AVIATION...GREAT DAY FOR FLYING. DRY NORTHERLY STABLE FLOW
ALOFT WILL MAINTAIN MOSTLY CLEAR SKIES WITH LIGHT WINDS. SIMILAR
TO MONDAY AM...WILL AGAIN HAVE PATCHY FOG AGAIN THIS AM UNTIL 17Z
JUST ABOUT ANYWHERE.

KPDX AND APPROACHES...VFR CONTINUES UNDER DRY STABLE AIR MASS.
WILL HAVE PATCHY FOG TO W AND N OF THE FIELD...BUT NOT LIKELY TO
AFFECT OPS AREA.      ROCKEY.
&&

.MARINE...LITTLE CHANGE. HIGH PRESSURE FIRMLY IN CONTROL THIS WEEK.
SURFACE PRESSURE GRADIENT REMAINS FAIRLY WEAK WHICH WILL KEEP
LIGHT NORTHERLY WINDS AT OR BELOW 15 KT FOR THE NEXT SEVERAL DAYS.
MAY HAVE GUSTS NEAR 20 KT OVER THE CENTRAL OREGON WATERS AS A
WEAK THERMAL TROUGH BUILDS UP THE SOUTH OREGON COAST. SEAS REMAIN
3 TO 5 FT.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND


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.


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