577
FXUS66 KPQR 050937
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
300 AM PDT FRI SEP 5 2008
SYNOPSIS
AN UPPER RIDGE WILL BE OVER THE EASTERN PACIFIC FOR THE
NEXT FEW DAYS...WITH A COUPLE OF WEAK DISTURBANCES RIDING OVER THE
RIDGE INTO THE ROCKY MOUNTAIN REGION. THE MAIN EFFECT OF THIS WILL BE
TO BRING DRY AND SLOWLY WARMING WEATHER TO THE FORECAST AREA WITH
SOME LIGHT ONSHORE FLOW TO THE NORTH COASTAL AREA. THE UPPER RIDGE
WILL INTENSIFY AND PUSH ONSHORE DURING THE WEEKEND PUSHING TEMPS
ABOVE NORMAL AS OFFSHORE FLOW DEVELOPS BY LATE IN THE WEEKEND AND
EARLY NEXT WEEK.
SHORT TERM
QUIET WEATHER ONCE AGAIN THIS MORNING WITH A FEW HIGH
CLOUDS DRIFTING OVERHEAD IN NORTHWEST FLOW. MARINE STRATUS IS FAIRLY
SPARSE ON THE COAST...WITH AREAS OF CLOUDS UP NORTH AND PATCHES DOWN
SOUTH. GIVEN THE WEAK ONSHORE FLOW LOW CLOUDS ARE NOT EXPECTED INLAND
THIS MORNING. THE MAIN PATTERN FOR THE NEXT COUPLE OF DAYS WILL BE A
STRONG BROAD UPPER RIDGE OVER THE NE PAC. A WEAK SHORT WAVE WILL MOVE
BY TO OUR N LATER TODAY WITH A FEW HIGH CLOUDS CONTINUING TO STREAM
BY OVERHEAD. MODELS ALSO SHOW SHALLOW MARINE CLOUDS INCREASING ALONG
THE N COAST LATER TODAY...AND POTENTIALLY PUSHING S ALONG THE COAST
AND ALSO UP THE COLUMBIA RIVER TONIGHT. LATEST NAM RATHER AGGRESSIVE
WITH THE INLAND VALLEY LOW CLOUDS SAT MORNING...IF THEY FORM BREAKOUT
WILL BE FAIRLY QUICK WITH NAM BUFR TOPS BELOW 1200 FT. INLAND VALLEY
TEMPS WILL BE IN THE LOWER TO MID 80S TODAY...THEN A FEW DEGREES
COOLER SAT WITH THE INCREASED ONSHORE FLOW AND POTENTIAL MORNING LOW
CLOUDS. SUN WILL WARM A FEW DEGREES WITH HIGHS IN THE MID 80S INLAND
AGAIN.
LONG TERM
DRY AND ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE
EXTENDED FORECAST. GUIDANCE CONTINUES TO INDICATE A STRONG RIDGE WILL
BE OVER THE PACIFIC INTO THE BEGINNING OF NEXT WEEK. A THERMAL TROUGH
WILL BE ALONG THE COASTLINE SUNDAY FOR OFFSHORE FLOW OVER MUCH OF THE
AREA. LONG TERM MODELS START TO FLATTEN THE RIDGE SOMEWHAT BY MIDWEEK
AS THE SURFACE THERMALLY INDUCED TROUGH MOVES INLAND WITH MAX TEMPS
COOLING TO THE LOWER 80S.
AVIATION
LOW IFR CLOUDS ALONG THE WA COAST SLOWLY SPREADING S
THIS MORNING...BUT WITH NORTHERLY LOW LEVEL WINDS CLOUDS NOT LIKELY
TO SPREAD FAR INLAND...WITH KAST MOST LIKELY SITE TO SEE THE LOW
CLOUDS. SOME LIGHT FOG ALREADY DEVELOPING ALONG THE CENTRAL COAST AT
KONP...BUT WITH LIGHT DRAINAGE OFFSHORE WINDS DEVELOPING...DO NOT
EXPECT DENSE FOG TO DEVELOP THERE THIS MORNING. NAM12 BOUNDARY LAYER
RH FIELDS SUGGEST A BETTER PUSH OF LOW CLOUDS BEGINNING LATE TODAY
PUSHING UP THE COLUMBIA RIVER TO KPDX BY LATE TONIGHT.
KPDX AND APPROACHES...VFR CONDITIONS WITH CLEAR SKIES EXPECTED
THROUGH THIS EVENING. A VERY SMALL POSSIBILITY FOR BRIEF MVFR LOW
CLOUDS EXISTS AFTER SUNRISE THIS MORNING.
MARINE
THERMAL INDUCED TROUGH REMAINS ALONG THE S OREGON COAST
EARLY THIS MORNING. EXPECT A DIURNAL STRENGTHENING OF WINDS LATE
TODAY AND CONTINUING INTO THE EVENING...SO WILL KEEP SMALL CRAFT FOR
WINDS UP THROUGH EVENING. SEAS TODAY TENDING TO BE LARGELY WIND
DRIVEN...WITH A SMALL UNDERLYING WESTERLY SWELL. SHORT PERIOD SEAS
IN THE SOUTHERN WATERS MAY APPROACH SMALL CRAFT FOR HAZARDOUS SEAS
CRITERIA BY EVENING...BUT NOT SURE YET THAT WINDS WILL BE STRONG
ENOUGH LONG ENOUGH...SO WILL HOLD OFF ON ISSUING ANY HAZARDOUS SEAS
HEADLINE. PERSISTENT PATTERN WILL YIELD NORTH WIND NEAR SMALL CRAFT
CRITERIA FOR THE NEXT SEVERAL DAYS.
PQR WATCHES/WARNINGS/ADVISORIES
OR/WA...SMALL CRAFT ADVISORY FOR WINDS CASCADE HEAD TO FLORENCE
THROUGH FRI EVENING.
SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO CASCADE
HEAD FRI AFTERNOON AND EVENING.
.PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION)
AST 0--00 PDX 00000 SLE 00000 EUG 00000
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.
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