FXUS66 KPQR 130939
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
238 AM PDT TUE MAY 13 2008

.SYNOPSIS...A WARM FRONT OFF THE WA AND OREGON COAST EARLY TODAY WILL
SLOWLY LIFT NE THROUGH NW OREGON AND WA THROUGH WED. LOW LEVEL FLOW
WILL TURN OFFSHORE BY THU AS A TROUGH OF LOW PRES BUILDS UP THE
OREGON COAST UNDER A STRONG UPPER LEVEL RIDGE. THE TROUGH WILL
EVENTUALLY MOVE INLAND THIS WEEKEND TURNING THE FLOW BACK ONSHORE.
&&

.SHORT TERM...RADAR SHOWS SOME LIGHT SHOWERS SPREADING SE ACROSS THE
COAST RANGE EARLY THIS MORNING. WARM FRONT IS OFFSHORE...WITH
SATELLITE SHOWING PRECIPITABLE WATER VALUES IN EXCESS OF 1.35 INCHES
OVERRUNNING THE FRONT. MODELS CONSISTENTLY SHOWING THE E PAC RIDGE
SUPPRESSED TO THE S TODAY...OPENING UP A WESTERLY FLOW OFF THE PAC
INTO NW OREGON AND WESTERN WA. WILL STICK WITH THE TREND OF KEEPING
POPS EXTENDED S TO THE CENTRAL COAST AND CENTRAL WILLAMETTE VALLEY
TODAY...WITH CATEGORICAL POPS IN THE FAR N PART OF THE FORECAST AREA.
AFTER A WAVE CROSSES OVER THE REGION LATER TODAY AND THIS EVENING...
MODELS SHOW UPPER RIDGE BUILDING N...AS WELL AS A SURFACE HIGH UP THE
OREGON AND WA COAST LATE TONIGHT AND EARLY WED. WITH THE LOSS OF
ONSHORE FLOW EARLY WED IN ADDITION TO STRONG SUBSIDENCE...EXPECT TO
SEE POPS DROP OFF QUICKLY.

WED NIGHT AND THU THE LONG EXPECTED UPPER RIDGE MOVES OVER AS LOW
LEVEL OFFSHORE FLOW DEVELOPS IN RESPONSE TO A THERMAL INDUCED TROUGH
DEVELOPING OFF THE COAST. AIR MASS WARMS QUICKLY THU...AND WITH THE
SURFACE TROUGH ALONG THE COAST WITH STRONG OFFSHORE FLOW AT 850 MB
...THE WARM TEMPERATURES SHOULD INCLUDE THE COASTAL STRIP.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
NO SIGNIFICANT CHANGES SEEN IN THE EXTENDED FORECAST. THE FORECAST
AREA WILL EXPERIENCE QUITE WARM AND POSSIBLY NEAR RECORD TEMPERATURES
TO END THE WEEK. A STRONG UPPER LEVEL RIDGE ALONG WITH A STRONG
THERMAL TROUGH ALONG THE COASTLINE WILL PERSIST INTO SAT. MODEL RUNS
VARY IN THE TIMING OF THE BREAKDOWN OF THE RIDGE...WITH CURRENT RUNS
NOW SHOWING THE RIDGE MOVING EAST OF THE CASCADES LATE SAT INTO SUN.
THIS WEATHER PATTERN WILL PRODUCE A MARINE PUSH IN ONSHORE FLOW SAT
NIGHT AND INTO SUNDAY...AND WILL BRING CLOUDY CONDITIONS AND NEAR
NORMAL TEMPERATURES TO BEGIN NEXT WEEK. BROWN
&&

.AVIATION...VFR CONDITIONS COVER THE AREA EARLY THIS MORNING. AN
APPROACHING WARM FRONT WILL SPREAD RAIN TO THE NORTHERN COAST WITH
MVFR CONDITIONS DEVELOPING LATER THIS MORNING AND CONTINUING
THROUGH THE AFTERNOON. AREAS OF MVFR WILL SPREAD INTO THE FAR NORTH
INTERIOR NEAR THE CASCADES THIS AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS IN THE KPDX AREA TODAY AND
TONIGHT.
&&

.MARINE...AN APPROACHING WARM FRONT WILL DEVELOP SMALL CRAFT WINDS
OVER THE NORTHERN WATERS THIS MORNING WHICH WILL CONTINUE THROUGH
THE AFTERNOON. THE MAIN PORTION OF THE WARM FRONT WILL MOVE ASHORE
BY LATE TODAY DECREASING THE SMALL CRAFT WINDS BY EARLY EVENING.
SEAS WILL REMAIN BELOW 10 FEET.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO
         CASCADE HEAD TODAY.
&&

.PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION)
AST +8400  PDX 77400  SLE 34100  EUG 11100
$$

MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.