359 
FXUS66 KPQR 011638
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 AM PST THU JAN 01 2004

.SYNOPSIS...COLD WINTER WEATHER EXPECTED IN THE FORECAST AREA INTO
NEXT WEEK. A PAC LOW IS MOVING THROUGH SOUTHWEST OREGON THIS MORNING
AND WILL MOVE INTO NORTHEAST OREGON THIS AFTERNOON...BRINGING MORE
RAIN AND SNOW ALONG WITH LOW SNOW LEVELS IN THE NORTH. ONSHORE FLOW
BEHIND THIS SYSTEM WILL KEEP SHOWERS WITH LOW SNOW LEVELS CONTINUING
THROUGH SAT. SOME MODIFIED ARCTIC AIR MAY MOVE INTO THE AREA SAT
NIGHT. MODELS CONTINUE TO SHOW A CHANCE OF LOW ELEVATION SNOW NEXT
WEEK AS SYSTEMS APPROACH FROM THE SOUTHWEST.
&&

.DISCUSSION...
.SHORT TERM...SATELLITE IR AND WATER VAPOR LOOPERS SHOW THE SURFACE
LOW MOVING ONSHORE ABOUT 12Z NEAR GOLD BEACH...TO SOUTH OF THE
WILLAMETTE VALLEY CURRENTLY. PRES FALLS SUPPORT GFS AND MESO ETA
MODEL TRACKS THROUGH REDMOND THIS MORNING INTO NORTHEAST OREGON THIS
AFTERNOON. NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWS INITIAL BAND
OF PRECIP FROM CORVALLIS THROUGH PORTLAND WITH A SECOND BAND FROM
EUGENE THROUGH MT HOOD. HAVE ISSUED A WINTER STORM WARNING FOR THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY WITH REPORTS OF 2 TO 3 INCHES
THERE ALREADY...A SNOW ADVISORY FOR THE CENTRAL COASTAL RANGE AND
HAVE CHANGED THE WINTER WEATHER ADVISORY FOR THE PORTLAND METRO AREA
TO A SNOW ADVISORY BECAUSE THE FREEZING RAIN HAS ENDED. WILL NEED TO
WATCH THE OREGON CASCADES AND THE COLUMBIA RIVER GORGE FOR POSSIBLE
HIGHER AMOUNTS THAN THE CURRENT ADVISORY LEVELS WE HAVE FOR THOSE
AREAS.

ONSHORE FLOW AROUND RESIDUAL LOW PRESSURE OFF THE WA COAST TONIGHT
AND FRI WILL KEEP SHOWERS GOING. WILL HAVE A SHOT AT ADVISORY AMOUNTS
IN THE MOUNTAINS...BUT IFFY IN THE VALLEYS. THICKNESS VALUES SUGGEST
THE SNOW LEVEL COULD BE CLOSE TO THE VALLEY FLOOR. A SHORT WAVE
DROPPING SOUTH THROUGH B.C. AND ACROSS THE PACIFIC NORTHWEST LATER
FRI NIGHT AND SAT INTENSIFIES THE LOW LEVEL ONSHORE FLOW FOR
POTENTIAL SNOW ADVISORY AMOUNTS EVEN AT LOWER ELEVATIONS. MODIFIED
ARCTIC AIR BEHIND THE SHORT WAVE SHOULD FILTER INTO THE AREA SAT
NIGHT. LIKENS

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...NO CHANGES.
PREVIOUS DISCUSSION FOLLOWS...00Z GFS RUN HAS BEEN CONSISTENT WITH
ITSELF AND THE ECMWF...AT LEAST WITHIN REASON...FOR THE PAST FEW
RUNS. MODIFIED ARCTIC AIR DROPS DOWN OVER WRN OREGON/WA ON SAT AND
REMAINS IN PLACE AS STRONG DEEP LOW PRESSURE SYSTEM MOVES TOWARD US
SUN NIGHT AND MON. TRACK OF THIS LOW IS UNCERTAIN BUT CURRENT MODELS
KEEP THE LOW JUST SOUTH OF OUR CWA. WILL BEGIN TO NUDGE FORECAST
TOWARD A SNOW AND CHANCE OF FREEZING RAIN FOR AT LEAST THE NORTHERN
ZONES OF OUR CWA. SCHNEIDER
&&

.PRELIMINARY POINT POPS
AST 76677  PDX 86677  SLE +6677  EUG +6677

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
.WA/OR...SNOW ADVISORY...NORTH AND CENTRAL OREGON CASCADES AND
          FOOTHILLS...WESTERN COLUMBIA GORGE...KPDX METRO AREA...
          CENTRAL COAST RANGE TODAY.
.WA/OR...WINTER STORM WARNING...CENTRAL AND SOUTHERN WILLAMETTE
          VALLEY THIS MORNING.
.WA/OR...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER TO
          FLORENCE.

$$