Winter Storm in Oregon, November 27 to 28, 2001

NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
230 AM PST TUE NOV 27 2001

.SYNOPSIS...WEAK HIGH PRESSURE TODAY WILL KEEP MOST OF SOUTHWEST
WASHINGTON AND NORTHWEST OREGON DRY...BUT WITH PERSISTENT AREAS OF
FOG AND LOW CLOUDS ESPECIALLY INLAND VALLEYS. STRONG PACIFIC STORM
WILL SPREAD STRONG WINDS TO THE COAST BY WEDNESDAY WITH RAIN LOCALLY
HEAVY OVER THE AREA LATER TONIGHT CONTINUING THROUGH WEDNESDAY. THE
FRONT WILL MOVE ONSHORE WEDNESDAY EVENING...WITH LOWERING SNOW LEVELS
AND NUMEROUS SHOWERS AND BREEZY CONDITIONS FOLLOWING THE FRONT
THROUGH THURSDAY. THE NEXT SYSTEM FRIDAY AND SATURDAY WILL HAVE MORE
RAIN...COASTAL WIND...AND MOUNTAIN SNOW. IT WILL REMAIN WET AND
RELATIVELY COOL THROUGH THE WEEKEND.

.DISCUSSION...
.SHORT TERM...LOW CLOUDS AND LOCAL FOG OVER THE INLAND AREAS THIS
MORNING AS HIGH PRESSURE BUILDS. LIGHT GRADIENTS TODAY SUGGEST CLOUDS
WILL BE SLOW TO CLEAR. A FEW LIGHT SHOWERS NORTH COASTAL ZONES IN
LIGHT ONSHORE FLOW WILL END TODAY.

ATTENTION THEN TURNS TO STRONG SYSTEM FOR LATE TUESDAY NIGHT AND
WEDNESDAY. MODELS ARE IN VERY GOOD AGREEMENT...THOUGH 06Z PACIFIC
ANALYSIS WAS HARD TO FIND OBSERVATIONS IN THE AREA OF DEVELOPMENT.
MODELS ALL SPREAD WARM FRONT ACROSS OUR FORECAST AREA LATER TONIGHT
AND NORTH INTO WASHINGTON WEDNESDAY MORNING...FOLLOWED BY THE STRONG
COLD FRONT LATER WEDNESDAY. RAIN AND WIND ARE THE MAIN MESSAGE. MESO
ETA HAS A VERY STRONG LOW LEVEL JET DEVELOP ON THE SOUTHERN AND
CENTRAL OREGON COAST LATE TONIGHT AND WEDNESDAY...WITH OVER 80 KNOTS
AT 950 AND 925 MB. TRIPLE POINT WITH SYSTEM MOVES ONSHORE CLOSE TO
ASTORIA...SO WILL RESTRICT WIND TO THE SOUTH OF ASTORIA. WILL ISSUE A
HIGH WIND WATCH SOUTH OF ASTORIA TO FLORENCE. GALE WARNING LOOKS
GOOD...WILL HAVE TO WATCH FOR STORM FORCE WINDS ON THE CENTRAL COAST.

WITH THE WARM FRONT SLOW TO MOVE NORTH...MAY NEED A SNOW ADVISORY IN
THE SOUTH WASHINGTON CASCADES FOR THE INITIAL PRECIPITATION LATE
TONIGHT AND WEDNESDAY MORNING BEFORE THE SNOW LEVEL WARMS ENOUGH.
WILL INCLUDE IN SPECIAL STATEMENT ON SNOW OUTLOOK FOR THE WEEK.

BENT BACK OCCLUSION COMES THROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS
WILL GIVE ANOTHER BURST OF RAIN AND WIND. SNOW LEVELS COME DOWN...AND
SHOULD NEED AT LEAST A SNOW ADVISORY FOR THE CASCADES. ONSHORE
OROGRAPHIC FLOW EASES LATE THURSDAY.

.LONG TERM...NEW EXTENDED MODELS STILL IN AGREEMENT OF KEEPING A LONG
WAVE TROUGH ALONG THE WEST COAST FRIDAY THROUGH MONDAY. MRF SAYS NEXT
SYSTEM LATE FRIDAY AND SATURDAY...WITH MORE COASTAL WIND...RAIN AND
MOUNTAIN SNOW. SYSTEMS STAY COOL WITH VALLEY RAIN AND MOUNTAIN SNOW.
BROAD BRUSH WILL CONTINUE. TOLLESON

AST 28+98 PDX 17+98 SLE 17+98 EUG 17+98

.PQR...GALE WARNING CAPE SHOALWATER TO FLORENCE.
       HIGH WIND WATCH NORTH OREGON COAST WEDNESDAY.
       HIGH WIND WATCH CENTRAL OREGON COAST LATE TUESDAY NIGHT AND
         WEDNESDAY.