553
FXUS66 KPQR 080424
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST SAT NOV 7 2009
SYNOPSIS
A COOL SHOWERY AIR MASS WILL CONTINUE TO SPREAD INTO THE
PACIFIC NORTHWEST TONIGHT. THE SHOWERS ARE EXPECTED TO TAPER OFF
SOME ON SUNDAY IN THE SOUTH...WHILE A WARM FRONT SHOULD MOVE THROUGH
THE NORTHERN AREAS FOR ADDITIONAL RAIN. A RATHER STRONG COLD FRONT
WILL MOVE THROUGH MONDAY AFTERNOON AND EVENING WITH MORE
RAIN...MOUNTAIN SNOW AND BRISK WINDS.
SHORT TERM
THE WIDESPREAD HEAVIER PRECIPITATION HAS MOVED OFF
WITH THE OCCLUDED FRONT THIS EVENING. SATELLITE AND RADAR SHOW
SCATTERED SHOWERS CONTINUING BEHIND THE FRONT. SNOWFALL TOTALS AT
CASCADE SNOTEL SITES AND AVALANCHE CENTER SITES SUGGEST TOTALS
AROUND 6 INCHES THIS AFTERNOON AND EVENING. AS THE HEAVIER AMOUNTS
ARE LIKELY PAST WITH THE FRONT AND THE H8 FLOW WEAKENS SLIGHTLY AND
BACKS SOME...WILL LET THE ADVISORY FOR SNOW EXPIRE AT 10 PM.
REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...
THE UPPER FLOW BEGINS TO SLOWLY BUCKLE SUN AND MON AS THE NEXT
FRONTAL SYSTEM DEVELOPS OFF THE COAST. THE MODELS SAY SOME SORT OF
WARM ADVECTION PRECIP MAY WILL SPREAD ACROSS THE NW HALF OF OUR AREA
SUN...WITH LOCAL MODERATE RAINFALL AMOUNTS AROUND ONE HALF INCH
INDICATED IN THE GFS AND NAM. THIS COULD REQUIRE ANOTHER WINTER
WEATHER ADVISORY IN THE S WA CASCADES SUN. CONDITIONS APPEAR TO DRY
OUT SUN NIGHT INTO MON MORNING IN THE SLIGHTLY WARMER SECTOR...THEN
THE ASSOCIATED STRONG COLD FRONT WILL MOVE IN MON AFTERNOON AND MOVE
E MON NIGHT. THIS FRONT SHOULD PRODUCE GUSTY WINDS ALONG THE COASTAL
STRIP...AND BREEZY CONDITIONS INLAND. SNOW LEVELS LIFT SOME AHEAD OF
THIS FRONT...SO WE WILL HAVE TO SEE IF THEY LOWER SOON ENOUGH TO GET
ENOUGH SNOW FOR ANOTHER WINTER WEATHER ADVISORY IN THE CASCADES.
RIGHT NOW IT IS LOOKING RATHER IFFY.
GFS SHOWS DRYING AGAIN ON TUE AHEAD OF THE NEXT SYSTEM...ALTHOUGH THE
ECMWF HAS FASTER TIMING WITH A MINIMAL PERIOD OF DRY WEATHER.
RW
LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS
MODELS IN FAIRLY GOOD AGREEMENT SHOWING A COOL UPPER TROUGH DROPPING
SE THROUGH THE REGION WED AND THU. THIS SHOULD BRING SHOWERY WEATHER
WITH SNOW LEVELS BETWEEN 3000 AND 4000 FT. EXTENDED MODELS ARE STILL
SHOWING A POTENTIAL BREAK IN THE WEATHER FROM LATE THU INTO AT LEAST
FRI MORNING AS A WEAK UPPER RIDGE MOVES THROUGH. ANOTHER PAC SYSTEM
LOOKS LIKELY FRI NIGHT AND SAT. RW
AVIATION
VFR/ OCCASIONAL MVFR CONDITIONS IN SHOWERS AND ISOLATED
THUNDERSTORSMS OVER THE FORECAST AREA THIS EVENING. THUNDERSTORMA
ACTIVITY WILL DIMINISH OVER THE INTERIOR PORTIONS THIS EVENING...BUT
CONTINUE ALONG THE COAST THROUGH THE NIGHT. SHOWERS WILL GRADUALLY
DECREASE AS THE NIGHT GOES ON. YET ANOTHER AREA OF SHOWERS IS
EXPECTED TO MOVE ONSHORE EARLY SUNDAY MORNING. SMALL HAIL IS
POSSIBLE WITH ANY OF THE HEAVIER SHOWERS.
KPDX AND APPROACHES...VFR/ LOCAL MVFR CONDITIONS IN SHOWERS. BRIEF
SMALL HAIL IS POSSIBLE WITH THE HEAVIER SHOWERS. SHOWERS TAPER OFF
OVERNIGHT...BUT AREAS OF MVFR CIGS MAY LINGER THROUGH THE NIGHT.
MORE RAIN EXPECTED SUN MORNING...POSSIBLY BRINGING MORE WIDESPREAD
MVFR.
MARINE
COASTAL BUOYS CONTINUE TO REPORT 19-22 FT SEAS. A SLOW
DOWNWARD TREND IN SEAS WILL CONTINUE THROUGH SUNDAY...WILL CONTINUE
THE HIGH SURF ADVISORY. ANOTHER GOOD CHANCE FOR GALES ANTICIPATED
EARLY MONDAY AS ANOTHER STRONG FRONT MOVES ACROSS THE COASTAL
WATERS. LONG RANGE MODELS ARE SUGGESTING THIS UNSETTLED WEATHER
PATTERN WILL CONTINUE WELL INTO THE UPCOMING WEEK.
PQR WATCHES/WARNINGS/ADVISORIES
WA/OR...SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO FLORENCE
OUT 60 NM THROUGH SUNDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER TO
FLORENCE OUT 60 NM THROUGH MONDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
SUNDAY NIGHT.
HIGH SURF ADVISORY SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST THROUGH SUNDAY AFTERNOON.
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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