Heavy Snow in Oregon, December 30 to 31, 2002

NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 AM PST MON DEC 30 2002

.SYNOPSIS...A SERIES OF PAC STORMS WILL MOVE THROUGH THE FORECAST
AREA THROUGH THE WEEK. THE STRONGEST STORMS ARE EXPECTED WED INTO
THU.

.DISCUSSION...
.SHORT TERM...COLD FRONT MANAGED TO NUDGE INTO THE N PART OF THE
FORECAST AREA ALLOWING STEADING PRECIP TO TURN SHOWERY.  FRONT WILL
LIFT N OF THE AREA BY MIDDAY IN RESPONSE TO A DEVELOPING WAVE NOW
NEARING 140W.  PRECIP WILL BECOME STEADY ONCE AGAIN...POSSIBLY HEAVY
AT TIMES COAST AND S.  FLOOD POTENTIAL OUTLOOK CONTINUES FOR THE
RIVERS DRAINING THE CENTRAL COAST RANGE. AT THIS TIME...IT APPEARS
ONLY THE LUCKIEMUTE RIVER WILL APPROACH FLOOD STAGE.  THE LULL IN
PRECIP UP N THIS MORNING SHOULD HELP LIMIT FLOODING POTENTIAL.  WINDS
HAVE ALSO REMAINED QUIT STRONG THIS MORNING ALONG THE CENTRAL COAST
WITH SUSTAINED 35 KT WINDS AT FLORENCE AT 15Z.  HAVE EXTENDED THE
HIGH WIND WARNING CENTRAL COAST TO RUN THROUGH 18Z.

GRADIENTS SHOWN BY MODELS TO WEAKEN THIS AFTERNOON BUT INCREASE AGAIN
OVER THE S CWA AS A DEVELOPING LOW MOVES ONTO THE S OREGON COAST.
DARKENING IN WATER VAPOR SATELLITE 36N/150W SUPPORTS FURTHER
DEVELOPMENT OF SURFACE LOW AS IT MOVES NORTHEAST THROUGH DISTRICT.
IMPRESSIVE PRESSURE FALLS OF 6 MB OVER A 3 HOUR PERIOD THIS EVENING
PER MESO-ETA ALONG THE S OREGON COAST.  HOWEVER...RAPID PRESSURE
RISES NOT AS STRONG BEHIND THE LOW AS MODELS BEGIN TO WEAKEN THE LOW
AS IN MOVES ON SHORE. MODELS ALSO KEEP STRONGEST GRADIENTS S OF OUR
CWA WITH RELATIVELY WEAK LOW LEVEL FLOW.  TAKING ALL THIS INTO
ACCOUNT...WILL NOT ISSUE A WATCH FOR THE FAR S BUT WILL WATCH THE LOW
DEVELOPMENT CLOSELY TODAY.  IF LOW APPEARS TO BE TRACKING FURTHER N
OR DEEPER THAN WHAT MODELS SHOW...THEN A LAST MINUTE WARNING MAY BE
NEEDED.

ANOTHER BURST OF SNOW IN THE CASCADES TODAY AS THE WAVE MOVES UP THE
FRONTAL BOUNDARY LATE TODAY AND TONIGHT.  THIS WILL INCREASE
PRECIPITATION AGAIN...AND WILL KEEP THE WINTER STORM WARNING UP
THROUGH TONIGHT.

SNOW LEVELS WILL DROP TO NEAR 2500 FEET ON TUE AS THE UPPER LEVEL
TROUGH AXIS MOVES ACROSS THE AREA. VIGOROUS UPPER LEVEL ENERGY NOW
ALONG 150W SHOULD BE ENOUGH TO PRODUCE SNOW ADVISORY AMOUNTS TUE
BEFORE BECOMING SHOWERY.

ANOTHER STRONG SYSTEM RIDES NORTHEAST TOWARD B.C. ON NEW YEARS
DAY...WITH MORE RAIN AND COASTAL WIND.

.LONG TERM...NO CHANGES MADE.

MERCER

AST 98858  PDX +9858  SLE ++858  EUG ++958

.PQR...SMALL CRAFT ADVISORY TODAY FROM CAPE SHOALWATER WA S TO
       FLORENCE OREGON.
      .HIGH WIND WARNING CENTRAL OREGON COAST THROUGH 1000 AM TODAY.
      .WINTER STORM WARNING THROUGH TONIGHT FOR THE SOUTH WA AND
       NORTH AND CENTRAL OREGON CASCADES.
      .FLOOD POTENTIAL OUTLOOK FOR RIVERS DRAINING THE CENTRAL COAST
       RANGE TONIGHT AND TUE.

ORZ001>013-WAZ019>023-039-040-311430-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OREGON
630 AM PST MON DEC 30 2002

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

.DAY ONE...

A WINTER STORM WARNING IS IN EFFECT FOR THE SOUTH WASHINGTON AND
NORTH AND CENTRAL OREGON CASCADES FOR TODAY AND TONIGHT.

.DAYS TWO THROUGH SEVEN...

POSSIBLE HIGH WINDS AT THE COAST WEDNESDAY AND THURSDAY.
FLOOD POTENTIAL OUTLOOK FOR RIVERS AND STREAMS DRAINING THE CENTRAL
COAST RANGE OF WESTERN OREGON FOR SHARP RISES TONIGHT AND TUESDAY TO
BANK FULL AND POSSIBLE FLOOD LEVELS ON THE LUCKIAMUTE RIVER EARLY
TUESDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.