464 
FXUS66 KPQR 272100
AFDPQR

NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
200 PM PDT SUN JUL 27 2003

.SYNOPSIS...AN UPPER LEVEL HIGH WILL BUILD OVER THE WESTERN U.S.
FOR THE EARLY PART OF THE WEEK...WEAKENING THE ONSHORE FLOW.  WEAK
IMPULSES ARE EXPECTED TO MOVE N INTO THE PAC NW DURING THE COURSE
OF THE WEEK.  LATE IN THE WEEK ONSHORE FLOW WILL INCREASE SOME AGAIN
AS THE UPPER LEVEL HIGH WEAKENS.

.DISCUSSION...
.SHORT TERM...ONSHORE FLOW TO WEAKEN AS UPPER HEIGHTS BUILD MON AND
TUE.  THIS SHOULD REDUCE MARINE LAYER TO JUST A SHALLOW ONE ALONG THE
IMMEDIATE COASTLINE...LIMITING MORNING CLOUDS AND FOG TO COASTAL
AREAS. ON WESTERN FRINGES OF UPPER RIDGE SOUTHERLY FLOW WILL TEND TO
SPREAD SOME MOISTURE UP FROM THE S AS SEEN IN WATER VAPOR LOOPS. 
WILL KEEP A MENTION OF THUNDERSTORMS OVER CASCADES NEXT FEW DAYS. 
AIR MASS WARMS CONSIDERABLY FOR THE SHORT TERM...AND WITH WEAKENED
ONSHORE FLOW WILL HAVE MINIMAL IMPACT FOR ANY MARINE AIR SNEAKING
INLAND.  MOS GUIDANCE HIGHS ALL RUNNING SEVERAL DEGREES TO COOL IN
THIS SITUATION AS LOWER LAYERS SHOULD MIX OUT TO NEAR DRY ADIABATIC
LAPSE RATES...MEANING 850 MB TEMPS SHOULD BE A PRETTY GOOD INDICATOR
FOR HIGHS.

.LONG TERM...12Z RUN OF GFS CONTINUES TO LIFT A SERIES OF VORTICES N
IN THE 500 MB FLOW THU AND FRI. WHILE THESE LOOK SUSPICIOUSLY LIKE
SOME SORT OF CONVECTIVE FEEDBACK...THE CONTINUED SOUTHERLY FLOW
PROBABLY WARRANTS A CONTINUED CHANCE OF THUNDERSTORMS ALONG THE
CASCADES.  UPPER HEIGHTS TEND TO BE SLOW TO FALL IN THE LATTER HALF
OF WEEK...SO WILL BUMP UP HIGH TEMPS A FEW DEGREES MOST DAYS THROUGH
THE EXTENDED.

AST 000000  PDX 000000  SLE 000001  EUG 000001

.PQR...SMALL CRAFT ADVISORY TODAY CAPE FALCON TO FLORENCE.

$$