Heavy Snow in Washington, February 7 to 8, 2002

NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
230 AM PST THU FEB 7 2002

.SYNOPSIS...LOW PRES OFF N CALIFORNIA COAST MOVES INTO SW OREGON LATE
TODAY AND PUSHES WELL E TONIGHT.  WRAP AROUND MOISTURE AROUND LOW
SPREADS OVER MOST OF AREA EXCEPT FAR N AND DECREASES TONIGHT AS LOW
MOVES E.  LOW PRES W OF VANCOUVER ISLAND PUSHES ASHORE N OF VANCOUVER
ISLAND TONIGHT BRINGING C UNSTABLE AIR MASS TO AREA LATER TONIGHT
WHICH CONTINUES THROUGH FRI MORNING.  HIGH PRES BUILDS OVER SE OREGON
FRI NIGHT AND WARM FRONT BRUSHES NW CORNER OF AREA.  FRONTAL ZONE
REMAINS OVER WASHINGTON SATURDAY THOUGH BRUSHES NW CORNER OF OREGON.
THIS PATTERN CONTINUES THROUGH SUNDAY BEFORE FRONT EDGES S THROUGH
AREA SUN NIGHT.

.DISCUSSION...
.SHORT TERM...ETA WEAKER AND SLOWER WITH LOW PRES OFF N CA COAST
MOVING ACROSS CENTRAL ORE LATE TODAY AND TONIGHT.  06Z ETA COMING
AROUND TO AVN SOLUTION THOUGH STILL SLOWER BUT ONLY SLIGHTLY WEAKER.
VAPOR SATELLITE SHOWS SHARP TROUGH DEVELOPING W OF 140W WITH HIGH
LEVEL MOISTURE LIFTING NE.  THIS COMBINED WITH ALREADY LOWER PRES AT
06Z ANALYSIS FAVOR STRONGER AVN.  OCCASIONAL SHOWERS THIS MORNING
TURN TO RAIN MOST AREA AS LOW LEVEL FLOW TURNS OFFSHORE WITH
APPROACHING LOW.  AVN/06Z ETA CLOSE IN PUTTING N EDGE OF STEADY RAIN
TO KKLS-TILLAMOOK LINE THIS AFTERNOON WITH SPOTTY SHOWERS N.
HEAVIEST PRECIPITATION S PART OF CWA WITH AIR COLD ENOUGH TO SUPPORT
GOOD SNOWS S PART OF CASCADES AND WILL CONTINUE SNOW ADVY THERE
THOUGH COULD GET CLOSE TO WARNING AMOUNTS.  WILL LOWER ADVY N PART AS
SNOW AMOUNTS LIGHT THERE.  LOW MOVES E TONIGHT WITH STEADY SNOW
DIMINISHING FOR A WHILE.  THEN LOW FROM S GULF OF ALASKA SPREADS COLD
AIR MASS OVER AREA INCREASING SHOWERS WITH MORE SNOW ALL CASCADES
LATE TONIGHT INTO FRI MORNING.  WILL LIKELY NEED NEW ADVY ALL AREAS
FOR THIS.  WITH COLD AIR MASS SNOW LEVEL LOWER TO NEAR 1500 FEET WITH
SOME SNOW HIGHER COAST MOUNTAINS AND FOOTHILLS OF CASCADES. HIGH PRE
REBOUNDS FRI AFTERNOON WITH SHOWERS DECREASING OVER AREA.  RIDGE
STRONGER FORCES MOST OF NEXT WARM FRONT N OF AREA THOUGH CLOSE ENOUGH
FOR RAIN N COAST AND CHANCE OVER MOST OF REST OF AREA.  BARO ZONE
STAYS MAINLY OVER WA SAT THOUGH FAR NW CORNER LOOKS TO BE IN ZONE AT
LEAST SOME OF THE TIME.  WITH S FLOW AHEAD OF ZONE TEMPS FAIRLY WARM
SAT.

.LONG TERM...EXTENDED MODELS FAIRLY CLOSE HAVE TENDED TOWARDS EURO
SOLUTION.  EURO/CANADIAN EVEN STRONGER ON RIDGE WOULD GIVE EVEN DRIER
WEATHER FOR MOST OF CWA ON SAT INTO EARLY SUN.  BY LATE SUN GULF
TROUGH STARTS PUSHING FRONT SE WITH FRONT PUSHING THROUGH AREA SUN
NIGHT.  HIGH PRES BUILDS OVER AREA MON DRYING OUT AREA.  FLOW BECOMES
SPLIT WITH MRF STRONGEST FLOW THOUGH SPLIT WHICH WOULD STILL LEAVE
CHANCE OF RAIN TUE THROUGH THU.  KOSOVITZ

AST 89878 PDX 88655 SLE 98644 EUG 98631

.PQR...SMALL CRAFT ADVISORY COASTAL WATERS.
       HEAVY SURF ADVISORY TODAY.
       SNOW ADVISORY CASCADES MT JEFFERSON S.