Heavy Snow in Oregon, April 1 to 3, 2003

NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 AM PST TUE APR 1 2003

.SYNOPSIS...THE REMAINS OF A WEAK COLD FRONT WERE OVER THE CASCADES
THIS MORNING AND WILL CONTINUE TO WEAKEN TODAY. AN UNSEASONABLY COLD
UPPER LOW CENTERED WAS CENTERED OFF 300 MILES OFF THE WASHINGTON
COAST THIS MORNING AND WILL SPREAD INCREASING PRECIPITATION AND
LOWERING SNOW LEVELS OVER OUR FORECAST AREA THIS AFTERNOON. THE BRIEF
STEADIER PRECIPITATION WILL TURN SHOWERY LATER TONIGHT AND CONTINUE
THROUGH WEDNESDAY. SNOW LEVELS WILL PLUNGE TO 1000 TO 1500 FEET BY
WEDNESDAY...WITH SIGNIFICANT ACCUMULATIONS OF SNOW LIKELY IN THE
CASCADES AND FOOTHILLS AND IN THE COAST RANGE AND PASSES. THE AIR
MASS WILL BE RATHER UNSTABLE...WITH POSSIBLE THUNDERSTORMS TONIGHT
THROUGH FRIDAY. THE UPPER LOW WILL LOOSEN ITS GRIP ON OUR WEATHER
THIS WEEKEND. ANOTHER WEATHER SYSTEM APPEARS HEADED FOR AREA MONDAY
FOR A RENEWED CHANCE OF RAIN.

.DISCUSSION...THE WEAK COLD FRONT FROM OVERNIGHT BROUGHT 1 TO 4
INCHES OF NEW SNOW TO THE CASCADES. ECHOES ARE STARTING TO DECREASE
AND WILL MOVE OFF TO THE EAST THIS AFTERNOON AS THE NEXT ROUND MOVES
ONSHORE. THE LEADING EDGE OF THE NEXT COLD DEVELOPING UPPER LOW
OFFSHORE WILL MOVE INTO THE FORECAST AREA THIS AFTERNOON. PRETTY
SHOWERY LOOKING PATTERN...BUT WILL PROBABLY GET A PERIOD OF STEADIER
PRECIPITATION WITH THE COMMA SHAPED FRONTAL BOUNDARY. PRECIPITATION
WILL TURN SHOWERY OVERNIGHT TONIGHT AND CONTINUE WEDNESDAY...WITH
THUNDERSTORMS POSSIBLE IN THE COASTAL WATERS AND ALONG THE COAST
TONIGHT SPREADING ONSHORE WEDNESDAY.

MESO ETA 6 HOUR AND 24 HOUR PRECIPITATION AMOUNTS SUGGEST POSSIBLE
WINTER STORM AMOUNTS IN THE HIGHER ELEVATIONS OF THE COAST RANGE THIS
AFTERNOON AND TONIGHT...AND WILL ISSUE A WINTER STORM WATCH ABOVE
2000 FEET. ELSEWHERE EXPECT SNOW ADVISORY AMOUNTS IN THE
CASCADES...FOOTHILLS...COAST RANGE BETWEEN 1000 AND 2000 FEET. WILL
ISSUE THAT THIS AFTERNOON.

THE LOW REMAINS ALONG THE COAST WEDNESDAY...STARTING TO LIFT OUT TO
THE NORTHEAST LATER WEDNESDAY AND WEDNESDAY NIGHT. THIS MAINTAINS
THE ONSHORE FLOW AND OROGRAPHICS INTO THE COAST RANGE AND INCREASES
IT INTO THE CASCADES...AND EXPECTED CONTINUE SIGNIFICANT SNOW
ACCUMULATIONS THEN. ANOTHER LOW SETS UP OFF THE COAST LATE
THURSDAY...FOR CONTINUED SHOWERY AND UNSTABLE WEATHER INTO FRIDAY.

SMALL CRAFT ADVISORY WINDS AND SEAS ARE EXPECTED TODAY...AND
CONTINUING MOST OF THE REST OF THIS WEEK.

.LONG TERM...EXTENDED MODELS CONTINUE TO SHOW SOME VARIATION IN THE
BREAKDOWN OF THIS PATTERN. STILL LOOKS AS THOUGH SHOWERS SHOULD
DECREASE THIS WEEKEND...WITH SOME HOPE OF A DRY DAY SUNDAY. GFS
CONTINUES TO SHOW ANOTHER SYSTEM MONDAY. TOLLESON

AST 9+999  PDX 89888  SLE 89888  EUG 89888

.PQR...SMALL CRAFT ADVISORY CAPE SHOALWATER TO FLORENCE.
       WINTER STORM WATCH IN THE WILLAPA HILLS AND THE NORTH AND
         CENTRAL OREGON COAST RANGE ABOVE 2000 FEET LATE TODAY
         THROUGH WEDNESDAY.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OREGON
630 AM PST TUE APR 1 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST OREGON AND SOUTHWEST
WASHINGTON.

.DAY ONE... TODAY

A VERY COLD STORM WILL MOVE INTO THE AREA LATER TODAY...BRINGING
SIGNIFICANT PRECIPITATION WITH SNOW LEVELS BETWEEN 1000 AND 1500
FEET. THIS WILL BRING UP TO 6 INCHES OF NEW SNOW TO THE
CASCADES...AND UP TO ONE OR TWO INCHES OF SNOW TO THE CASCADE
FOOTHILLS AND COAST RANGE PASSES.

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

LOW SNOW LEVELS AND CONTINUED SHOWERY WEATHER WILL BRING MORE
ACCUMULATING SNOW TO THE CASCADES AND FOOTHILLS...AND COAST RANGE
PASSES. IN THE CASCADES 4 TO 8 INCHES OF NEW SNOW CAN BE EXPECTED
WEDNESDAY AND THURSDAY...WITH 2 TO 4 INCHES POSSIBLE EACH DAY IN THE
CASCADE FOOTHILLS...AND 2 TO 4 INCHES POSSIBLE IN COAST RANGE PASSES.
SNOW LEVELS WILL GRADUALLY RISE...AND PRECIPITATION SHOULD TAPER OFF
FRIDAY INTO THE WEEKEND.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO SKYWARN PROCEDURES

ORZ003-004-010>013-WAZ019-020-040-012300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PORTLAND OR
544 AM PST TUE APR 1 2003

...LOW SNOW LEVELS AND SIGNIFICANT SNOW ACCUMULATIONS ARE EXPECTED
IN THE CASCADES...THE CASCADE FOOTHILLS...AND THE COAST RANGE OF
SOUTHWEST WASHINGTON AND NORTHWEST OREGON THIS WEEK...

SOME OF THE LOWEST SNOW LEVELS OF THE WINTER SEASON ARE EXPECTED IN
THE MOUNTAINS OF SOUTHWEST WASHINGTON AND NORTHWEST OREGON THIS
WEEK...ACCOMPANIED BY RATHER SIGNIFICANT LATE SEASON SNOWFALL.

AFTER A RELATIVELY WEAK SYSTEM BRINGS A FEW INCHES OF SNOW TODAY
DOWN TO THE 2500 OR 3000 FOOT LEVEL IN THE
MOUNTAINS...AN UNSEASONABLY COLD STORM SYSTEM FROM THE GULF OF
ALASKA WILL ARRIVE THIS LATER THIS AFTERNOON AND EVENING. SNOW
LEVELS AROUND 2500 FEET THIS AFTERNOON WILL REALLY TUMBLE BY
WEDNESDAY MORNING...TO NEAR 1000 FEET IN THE NORTH AND 1500 TO 2000
FEET ELSEWHERE. SNOW LEVELS WILL REMAIN AROUND 1500 TO 2000 FEET
WEDNESDAY AFTERNOON AND THURSDAY.

SIGNIFICANT SNOW ACCUMULATIONS ARE LIKELY IN THE CASCADES...
ESPECIALLY WEDNESDAY THROUGH THURSDAY NIGHT. ACCUMULATIONS OF UP TO
6 INCHES OF NEW SNOW ARE POSSIBLE THIS AFTERNOON THROUGH WEDNESDAY
MORNING...AND AGAIN WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WITH
SNOW LEVELS THIS LOW...ACCUMULATING SNOW IS ALSO LIKELY IN THE COAST
RANGE AND CASCADE FOOTHILLS...WHERE 1 TO 2 INCHES ARE POSSIBLE
THROUGH TONIGHT...THEN 2 TO 4 INCHES ARE LIKELY WEDNESDAY AND AGAIN
THURSDAY. MOUNTAIN CLIMBERS AND MOTORISTS DRIVING OVER COAST RANGE
AND CASCADE PASSES SHOULD BE PREPARED FOR WINTER WEATHER CONDITIONS
AND EXERCISE CAUTION WHEN HEADING FOR THE MOUNTAINS.