Area Forecast Discussion
Issued by NWS Portland, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPQR 080425
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
804 PM PST SUN FEB  7 2016

.SYNOPSIS...AN UPPER RIDGE WILL CONTINUE OVER THE PACIFIC NORTHWEST
THROUGH TUESDAY. RESULTANT OFFSHORE FLOW THROUGH THE GORGE WILL
INCREASE TONIGHT AND CONTINUE THROUGH AT LEAST TUESDAY. LOOK FOR MORE
VALLEY FOG AND LOW CLOUDS IN THE NIGHTS AND MORNINGS AWAY FROM THE
GORGE BUT WINDY CONDITIONS IN THE WESTERN GORGE AND IN PARTS OF THE
PORTLAND AND VANCOUVER AREAS. THE FIRST SYSTEM THAT WILL TRY TO BREAK
DOWN THE UPPER RIDGE WILL ARRIVE AT THE COAST WEDNESDAY...WITH
SUBSEQUENT SYSTEMS BRINGING SOME RAIN AT TIMES THE REMAINDER OF NEXT
WEEK AND NEXT WEEKEND.
&&

.SHORT TERM...TONIGHT THROUGH WEDNESDAY...HIGH AND DRY FOR THE NEXT
FEW DAYS. CURRENT SATELLITE LOOP SHOWS UPPER RIDGE AXIS OFFSHORE AT
ABOUT 126W. SURFACE PRESSURE ANALYSIS FROM 00Z HAS THE THERMAL TROUGH
JUST A FEW MILES OFFSHORE. THIS CERTAINLY HELPED TO BOOST MAX TEMPS
ON THE COAST INTO THE 60S. MOST AREAS INLAND ALSO WARMED INTO THE LOW
60S UNDER DRY OFFSHORE FLOW. THE EXCEPTION WAS THE SOUTH WILLAMETTE
VALLEY WHERE A STUBBORN TEMPERATURE INVERSION HELD FOG OR LOW STRATUS
THROUGH THE DAY.  THE HIGH TEMP AT EUGENE WAS 48 DEGREES. FOG AND
STRATUS WILL EXPAND NORTH THROUGH THE INTERIOR VALLEYS
TONIGHT...SKIPPING THE WINDY AREAS THROUGH AND NEAR THE GORGE. MODELS
SHOW STRONGER OFFSHORE FLOW AT THE COAST MONDAY SO SOME LOCATIONS MAY
NEAR OR EXCEED 70 DEGREES.

OFFSHORE SURFACE PRESSURE GRADIENT THROUGH THE GORGE FROM TROUTDALE
TO THE DALLES SURPASSED 4 MB THIS AFTERNOON AND IS NEAR 6 MB AT 8 PM.
THE GRADIENT WILL CONTINUE TO INCREASE TO 7 OR 8 MB
OVERNIGHT...THEN CONTINUE THROUGH TUESDAY. THIS WILL BRING WINDS
GUSTING TO AROUND 50 OR 55 MPH AT CORBETT AND ROOSTER ROCK...AND 65
TO 75 MPH OR SO AT CROWN POINT. THIS EAST WIND EVENT IS MOSTLY A GAP
FLOW EVENT...WITH AN INVERSION DEVELOPING NEAR THE CASCADE CREST.
THUS THE WINDS WILL AFFECT THE WESTERN COLUMBIA RIVER GORGE AND PARTS
OF THE PORTLAND AND VANCOUVER METRO AREAS THE MOST...AND RESTRICT FOG
IN THOSE AREAS. BUT AREAS AWAY FROM THE GORGE WILL LIKELY CONTINUE TO
SEE NIGHT AND MORNING FOG AND LOW CLOUDS THROUGH WEDNESDAY.

THE AIR MASS IS QUITE WARM ABOVE THE DEVELOPING INVERSION...AND WE
WILL LIKELY SEE TEMPS WELL UP INTO THE 60S IN PARTS OF THE COAST
RANGE AND CASCADE FOOTHILLS THE NEXT COUPLE OF DAYS...AND POSSIBLY
NEAR THE COAST. SOME AREAS IN THE VALLEYS THAT DO NOT HAVE MUCH FOG
COULD GET THERE AS WELL.

EAST WINDS RELAX TUESDAY NIGHT AND WEDNESDAY AS THE UPPER RIDGE MOVES
EAST AND THE FIRST SYSTEM TRYING TO KNOCK DOWN THE UPPER RIDGE
REACHES OR APPROACHES THE COAST. WE SHOULD STILL SEE QUITE A BIT OF
MORNING FOG INLAND WEDNESDAY MORNING...AND PERHAPS SOME SMALL CHANCES
OF RAIN ALONG THE COAST AS THIS FIRST SYSTEM WEAKENS DRAMATICALLY.
TOLLESON /MH

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...ACTIVE AND
MORE SEASONABLE WEATHER PATTERN SETS UP FOR LATE THIS WEEK. COAST
MAY SEE SOME SPRINKLES OR LIGHT RAIN WEDNESDAY NIGHT INTO THURSDAY
AS A FRONTAL BOUNDARY STALLS OFFSHORE. THE FRONT IS FINALLY PUSHED
EASTWARD ON FRIDAY...BRINGING A DECENT CHANCE FOR RAIN ACROSS
WESTERN OREGON AND SOUTHWEST WASHINGTON. RAIN TURNS TO SHOWERS
BEHIND THE FRONT AND STARTS TO TAPER OFF LATE FRIDAY INTO SATURDAY.
SATURDAY COULD BE MOSTLY DRY BEFORE ANOTHER SYSTEM BRINGS MORE RAIN
ON SUNDAY. -MCCOY
&&

.AVIATION...OFFSHORE SURFACE GRADIENT CONTINUES TO INCREASE THIS
EVENING. AS OF 04Z THE KTTD-KDLS GRADIENT WAS CLOSE TO -6 MB. VFR
ACROSS THE AREA...EXCEPT FOR LIFR BETWEEN KCVO AND NRN DOUGLAS
COUNTY. DO NOT EXPECT THIS AREA TO IMPROVE AT ALL UNTIL 18Z MON
OR A LITTLE LATER. THE REMAINDER OF THE AREA WILL REMAIN VFR
THROUGH MON EVENING. HOWEVER...THERE IS A CHANCE OF PATCHY IFR IN
THE INTERIOR VALLEYS NORTH OF KCVO 10Z-18Z.

KPDX AND APPROACHES...VFR EXPECTED TO PREVAIL THROUGH MON EVENING.
EAST WIND GUSTING TO 35 KT AT THE WEST END OF THE COLUMBIA GORGE
WILL INCREASE MON...WITH GUSTS UP TO 50 KT POSSIBLE BY 00Z TUE.
THERE IS THE CHANCE A LIGHT WEST DRIFT DEVELOPS AT THE TERMINAL
LATE TONIGHT...WHICH WOULD INCREASE THE THREAT OF LOCAL IFR/LIFR.
HOWEVER...AS THE OFFSHORE GRADIENT STRENGTHENS IT WILL ALSO HELP
DRY THE NEAR-SURFACE LAYER. WILL LEAN TOWARD NO VISIBILITY
RESTRICTIONS AT THE TERMINAL LATE TONIGHT AND MON MORNING.
WEISHAAR

&&

.MARINE...NO SIGNIFICANT WIND ISSUES THROUGH AT LEAST MID-WEEK.
OFFSHORE WIND WILL CONTINUE THROUGH TUE...WITH GUSTS UP TO 20 KT
LIKELY NEAR COASTAL TERRAIN GAPS. NEXT THREAT OF SMALL CRAFT
ADVISORY LEVEL WIND SPEEDS LOOKS TO OCCUR WED NIGHT.

SEAS RUNNING 5-6 FT THIS EVENING...BUT WILL GRADUALLY BUILD
OVERNIGHT THROUGH MON MORNING...PEAKING IN THE 10 TO 12 FT RANGE.
MODELS SHOW A MORE ACTIVE WEATHER PATTERN THE LATTER HALF OF THE
WEEK AND NEXT WEEKEND...WITH POSSIBLE GALE FORCE WIND CONDITIONS
AT TIMES FRI THROUGH SUN.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM TO 9 PM PST
     MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
     OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 10 AM TO
     9 PM PST MONDAY.

&&

$$

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.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.