FXUS66 KPQR 261035
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
235 AM PST THU NOV 26 2009
.SYNOPSIS...A MOIST FRONTAL SYSTEM IS APPROACHING THE NORTH OREGON
COAST THIS MORNING...AND WILL MOVE TO THE CASCADES BY EVENING. THE
HEAVIEST RAIN WILL BE ALONG THE NORTHERN OREGON AND SOUTH WASHINGTON
COAST RANGE. THE UPPER TROUGH SLIDES ACROSS THE FORECAST AREA LATE
THURSDAY NIGHT AND FRIDAY MORNING. A STALLED FRONT MAY BRING MORE
PRECIPITATION MAINLY TO NORTHERN AREAS FOR THE WEEKEND...THEN A
DRIER WEATHER PATTERN LOOKS POSSIBLE FOR MUCH OF NEXT WEEK.
&&
.SHORT TERM...A FRONTAL SYSTEM IS APPROACHING THE NORTH OREGON COAST
THIS MORNING AND WILL MOVE THROUGH THE FORECAST AREA TODAY...MOVING
TO THE CASCADES BY EVENING. SATELLITE IMAGERY SHOWS TOW LOWS
DEVELOPING ALONG THE FRONT...ONE OVER THE SOUTHERN END OF VANCOUVER
ISLAND AND THE OTHER NEAR 41N 133W. THIS LOW CENTER WILL MOVE
NORTHEAST ALONG THE FRONT. THERE IS STILL SOME QUESTION AS TO THE
EXACT LOCATION AND STRENGTH OF THIS LOW. 06Z MODELS ARE A LITTLE
SLOWER THAN PREVIOUS MODELS RUNS...BRINGING THE LOW ONSHORE AROUND
00Z FRIDAY. GFS BRINGS THE LOW ONSHORE NEAR NEWPORT...WHILE THE NAM
BRINGSTHE LOW ONSHORE NEAR ASTORIA. THIS SEEMS TO BE A FAIRLY WET
SYSTEM WITH PRECIPITABLE WATER AMOUNTS UP TO 1.30 INCHES. THE LOW
WILL ALSO SERVE AS A FOCUSING MECHANISM FOR RAINFALL. EXPECT SOME
PRETTY DECENT RAIN RATES OVER SOUTHWEST WASHINGTON AND THE NORTH
OREGON COAST AND COAST RANGE THANKSGIVING. THE LOW DOES NOT LOOK LIKE
A STRONG WIND PRODUCER. CURRENT FORECAST OF 35-45 MPH GUSTS ALONG THE
COASTAL HEADLANDS LOOKS SUFFICIENT.
POST-FRONTAL AIR MASS MOVES IN THURSDAY NIGHT. 850 MB OROGRAPHIC
COMPONENT NOT VERY IMPRESSIVE...ESPECIALLY ON THE NEW GFS. SNOW
LEVELS DROP WELL BELOW THE PASSES BY FRIDAY MORNING...BUT QPF AMOUNTS
DO NOT LOOK LIKE ENOUGH TO GIVE SNOW ADVISORY AMOUNTS TO THE
CASCADES. LIKENS
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...MODELS IN
FAIRLY GOOD AGREEMENT THROUGH THE EXTENDED PERIOD. A BRIEF POST
FRONTAL RIDGE WILL BRING GENERALLY MOSTLY CLOUDY WEATHER TO THE
FORECAST AREA SUNDAY AND MOST OF MONDAY. A SHORTWAVE WILL PASS BY TO
THE NORTH LATE MONDAY BRINGING RAIN TO THE AREA...MAINLY TO THE NORTH
PART. THE RIDGE APPEARS TO REBOUND AGAIN FOR THE MIDDLE OF NEXT
WEEK...WITH ALL MODELS COMING INTO AGREEMENT FOR THIS SOLUTION
THROUGH THE END OF THE WEEK. BROWN
&&
.AVIATION...PATCHY FOG IN THE VALLEY SHOULD DISSIPATE SLOWLY AS
HIGHER CLOUDS PUSH INTO THE AREA TODAY. RAIN AND MVFR CONDITIONS
ARE EXPECTED ALONG THE NORTH COAST THIS MORNING. THE FRONT MOVES
ONSHORE IN THE AFTERNOON WITH RAIN DECREASING BUT MVFR LIKELY TO
CONTINUE. INLAND AREAS...MAINLY VFR EARLY TODAY...UNTIL LOWER
CLOUDS IMPACT THE AREA LATER THIS AFTERNOON AS THE FRONT MOVES
THROUGH.
KPDX AND APPROACHES...MAINLY VFR CONDITIONS EARLY...THOUGH LOCALIZED
FOG ON WESTERN APPROACHES THROUGH 10Z OR SO. LIGHT EAST WIND SHOULD
KEEP KPDX OUT OF FOG THREAT.
&&
.MARINE...SMALL CRAFT FOR WINDS BEGIN 18Z TODAY AND CONTINUE THROUGH
EVENING...WITH THE SOUTHERN WATERS IMPACTED BY THE NEXT FRONTAL
SYSTEM FIRST. SEAS PEAKING AROUND 16 FT TODAY AND FRIDAY WITH A
BRIEF LULL IN BETWEEN. SEAS ARE NOT LIKELY TO DROP BELOW 10 FT UNTIL
LATE WEEKEND OR EARLY NEXT WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WIND CAPE SHOALWATER TO
CASCADE HEAD THROUGH THIS EVENING.
SMALL CRAFT ADVISORY FOR WIND CASCADE HEAD TO FLORENCE
EARLY THIS MORNING THROUGH THIS EVENING.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE
SHOALWATER TO FLORENCE THROUGH FRI AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER
BAR CONDITIONS THROUGH FRI 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.
