Area Forecast Discussion
Issued by NWS Portland, OR

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 302222
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
221 PM PST FRI JAN 30 2015

.SYNOPSIS...AN UPPER RIDGE AND OFFSHORE FLOW WILL PRODUCE RELATIVELY
MILD TEMPERATURES FOR JANUARY...WITH AREAS OF VALLEY FOG AND EAST
WINDS NEAR THE MOUTH OF THE COLUMBIA RIVER GORGE THROUGH SATURDAY
NIGHT. EXPECT A DECENT SHOT OF RAIN IN SOUTHWEST WASHINGTON AND
NORTHWEST OREGON SUNDAY INTO SUNDAY EVENING AS A PACIFIC FRONT MOVES
THROUGH. ANOTHER GOOD SHOT OF RAIN APPEARS LIKELY ON MONDAY AS
ANOTHER PACIFIC LOW AND FRONT MOVES BY. SOME MORE RAIN IS POSSIBLE
MID WEEK FROM A WARM FRONT THOUGH CONFIDENCE IN THE DETAILS AND
TIMING IS LOW. A SERIES OF WETTER COLD FRONTS IS LIKELY LATE NEXT
WEEK INTO NEXT WEEKEND. SIGNIFICANT SNOWS AT CASCADE PASS LEVEL
APPEAR UNLIKELY DURING THE NEXT WEEK.
&&

.SHORT TERM...TONIGHT THROUGH MONDAY...THE PATTERN OF FOG AND LOW
CLOUDS THIS AFTERNOON IS PRETTY MUCH WHAT WE SAW THURSDAY AFTERNOON
JUST BEFORE IT ALL CLEARED...AND EXPECT IT TO MOSTLY CLEAR AGAIN THIS
AFTERNOON AND EARLY EVENING. THERE WAS A BIT OF A LULL IN THE
GRADIENT THROUGH THE GORGE THIS MORNING BUT THE GRADIENT IS BACK UP
TO 6.3 MB EARLY THIS AFTERNOON. THE NAM12 MODEL SAYS THE GRADIENT IS
GOING TO WEAKEN A BIT AGAIN TONIGHT AND EARLY SATURDAY...AND IF IT
DOES...THE FOG COVERAGE TONIGHT AND SATURDAY MORNING WOULD BE A BIT
MORE EXTENSIVE THAN THIS MORNING...AND HAVE TRENDED THE GRIDS THAT
WAY. WOULD ALSO EXPECT A BIT SLOWER CLEARING SATURDAY AFTERNOON. BUT
CONFIDENCE IN THAT IS ONLY MODERATE AT BEST AS THE LOW CLOUDS IN THE
COLUMBIA BASIN REMAIN SOLID AND THIS WOULD SUGGEST THE WINDS MIGHT
NOT CHANGE TOO MUCH.

THE GRADIENT THROUGH THE GORGE INCREASES LATE SATURDAY AND SATURDAY
NIGHT AS THE HIGH PRESSURE EAST OF THE CASCADES STRENGTHENS SOME DUE
TO THE PASSAGE OF A WEAK SYSTEM WELL TO OUR NORTH AND EAST. THIS MAY
AFFECT THE FOG FORMATION SOME NEAR PORTLAND AND VANCOUVER...BUT THE
REST OF THE VALLEY AREAS SHOULD SEE MORE FOG AGAIN OVERNIGHT SATURDAY
NIGHT.

THE MODELS ARE SHOWING THE NEXT FRONTAL SYSTEM APPROACHING THE NORTH
COASTAL AREAS LATE SATURDAY NIGHT AND MOVING THROUGH SOUTHWEST
WASHINGTON AND NORTHWEST OREGON DURING THE DAY SUNDAY AND EARLY
SUNDAY EVENING. SPED UP THE ARRIVAL OF THE PRECIPITATION UP A TOUCH
AND RAISED POPS PREVIOUSLY IN THE MORNING UPDATE. WE SHOULD SEE A
DECENT SHOT OF QPF FROM THIS SYSTEM...WITH THE HIGHER TERRAIN SEEING
A HALF INCH OR MORE AND THE VALLEYS MAYBE A QUARTER OF AN INCH. A BIT
WETTER SYSTEM IS EXPECTED MONDAY...WITH AMOUNTS A BIT HIGHER THAN ON
SUNDAY...MAYBE ONE AND A HALF TO TWO TIMES HIGHER. MAY SEE SOME
BREEZES ON THE COAST MONDAY AS A 1005 MB SURFACE LOW HEADS TOWARD
VANCOUVER ISLAND. UNFORTUNATELY...SNOW LEVELS REMAIN RATHER HIGH WITH
THESE SYSTEMS...WITH ANY SNOW IN THE HIGHER CASCADES IN THE NORTH
PART OF OUR FORECAST AREA. TOLLESON

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY...IN THE WAKE OF THE SYSTEM
THAT MOVES THROUGH MONDAY...THE MODELS DEVELOP A WARM FRONT AND
ATTEMPT TO EVENTUALLY LIFT IT NORTH THROUGH THE PACIFIC NORTHWEST IN
THE MID WEEK PERIOD. UNFORTUNATELY...THE MODELS ARE HAVING A TOUGH
TIME SETTLING ON WHEN AND WHERE IT WILL FORM AND HOW WET IT WILL BE.
IT WILL LIKELY FORM SOMEWHERE OVER SOUTHWEST OREGON OR EXTREME
NORTHERN CALIFORNIA...THEN LIFT NORTH AROUND WEDNESDAY. FOR NOW HAVE
BROAD BRUSHED THE POPS A BIT DUE TO THE TIMING AND INTENSITY
PROBLEMS. THE NEXT RATHER MATURE AND DECENTLY STRONG OCCLUDED FRONT
COMES IN AROUND THURSDAY...FOLLOWED BY A SERIES OF RATHER WET FRONTS
LATE NEXT WEEK INTO THE WEEKEND. THE GENERAL TREND NEXT WEEK IS
TOWARD A WETTER MORE ACTIVE PATTERN. AT THIS POINT...OTHER THAN A
COUPLE OF BRIEF DIPS...SNOW LEVELS REMAIN RATHER HIGH AND THESE
SYSTEMS WILL NOT LIKELY ADD MUCH IF ANYTHING TO THE DEFICIENT SNOW
PACK IN THE CASCADES. TOLLESON
&&

.AVIATION...LITTLE CHANGE IN OVERALL PATTERN FOR NEXT 24 HRS. LIGHT
OFFSHORE FLOW CONTINUES...WITH VFR CONDITIONS. STILL HAVE WIDESPREAD
MVFR CLOUDS IN COLUMBIA BASIN INTO THE MID GORGE. REMNANTS OF LOW
CLOUDS EAST OF I-5 FROM SALEM TO COTTAGE GROVE WILL GRADUALLY BREAK
UP THIS AFTERNOON. HOWEVER...WITH LIGHT WINDS AND COOL AIR
MASS...DOES APPEAR THAT WILL HAVE WIDESPREAD FOG AND LOW CLOUDS
REFORM LATER THIS EVENING...WITH AREAS WHERE VIS BELOW ONE HALF MILE
AT TIMES. SUCH CONDITIONS WILL PERSIST SAT AM.

KPDX AND APPROACHES...VFR THIS EVENING. AREAS OF IFR FOG/STRATUS
REFORM TO N AND NW OF OPS AREA 02Z TO 05Z...AND SPREAD BACK INTO
FIELD BETWEEN 06Z AND 09Z. VIS WILL BE 1/4 TO 1/2 MILE FROM 10Z
THROUGH AT LEAST 18Z SAT. LIKE TODAY...THE FOG AND LOW CLOUDS WILL
BREAK UP SAT AFTERNOON AS EAST WINDS PICK UP.     ROCKEY.
&&

.MARINE...LITTLE CHANGE. HIGH PRES REMAINS OVER THE REGION INTO
SAT...WITH WINDS 15 KT OR LESS AND SEAS RUNNING 5 TO 6 FT.

WILL SEE PATTERN CHANGE NEXT WEEK...AS A SERIES OF FRONTS PUSH INTO
THE REGION. EACH WILL BE PROGRESSIVELY STRONGER...WITH WINDS 20 TO 25
KT AT TIMES LATER SUN AND SUN NIGHT...WITH GUSTS 30 TO 35 KT LIKELY
ON MON AS NEXT FRONT PUSHES INTO THE REGION. IF PATTERN HOLDS...GOOD
CHANCE OF SOUTHERLY GALES NEXT THU AND FRI...WITH SEAS BUILDING INTO
THE MID AND UPPER TEENS.    ROCKEY.
&&

.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.



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