078
FXUS66 KPQR 201057
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
255 AM PST FRI DEC 20 2024
SYNOPSIS
RATHER BENIGN WEATHER TODAY, UNDER MOSTLY CLOUDY AND MILD
CONDITIONS. THEN, BACK TO RAIN, AS THE FIRST IN A SERIES OF FRONTS
WILL PUSH ACROSS THE REGION ON SATURDAY. SNOW WILL CONTINUE ACROSS
THE HIGH CASCADES. NEXT FRONT ARRIVES ON SUNDAY. THEN, A BREAK
ARRIVES ON MONDAY, BUT MORE RAIN AND MOUNTAIN SNOW EXPECTED THROUGH
BULK OF NEXT WEEK.
SHORT TERM...(TODAY THROUGH SUNDAY)
MILD TEMPERATURES THIS MORNING ACROSS REGION, WITH TEMPERATURES IN
THE MID TO UPPER 40S, THOUGH A FEW SPOTS HOLDING CLOSE TO 50. DO HAVE
AREAS OF FOG AND LOW CLOUDS IN THE SOUTH WILLAMETTE VALLEY, WHERE
VISIBILITY HAS BEEN UNDER A MILE AT TIMES IN/AROUND EUGENE. THAT FOG
WILL GRADUALLY THIN AND LIFT TO STRATUS LATER THIS AM.
MAIN STORY IS THE THE CONTINUED MOIST AND MILD SOUTHWEST FLOW ALOFT.
GENERALLY, WILL REMAIN DRY ACROSS THE REGION TODAY, THOUGH MAY SEE A
FEW PASSING SPRINKLES AT TIMES. OTHERWISE, VARIABLE CLOUDS AND
TEMPERATURES IN THE 50S, WITH BREEZY EAST WINDS IN/NEAR WESTERN
COLUMBIA GORGE INTO THE EAST PORTLAND/VANCOUVER METRO AREA. THERE IS
A CHANCE, ALBEIT SMALL, THAT A FEW SPOTS ALONG THE COAST COULD REACH
60 TO 62 FOR HIGHS TODAY. THE RECORD WARMEST EVER TEMPERATURE IN
DECEMBER FOR ASTORIA IS 64 DEG (BACK ON 26 DEC 1980).
DRY TONIGHT AS THE REGION AWAITS THE NEXT FRONT. WILL BE DRY, WITH
VARIABLE CLOUDS. AGAIN, COULD SEE SOME SPOTTY FOG ACROSS THE INLAND
VALLEYS. WILL SEE AN UPTICK OF THE OFFSHORE FLOW, WITH EASTERLY WINDS
5 TO 15 MPH ALONG THE COAST AND ACROSS CLARK COUNTY AND NORTH
WILLAMETTE VALLEY. BUT, BIT STRONG IN THE WESTERN COLUMBIA GORGE OUT
ACROSS THE EAST PORTLAND/VANCOUVER METRO, WHERE WILL GENERALLY HAVE
EAST WINDS GUSTING 30 TO 40 MPH. MORE EXPOSED SPOTS IN THE GORGE
LIKELY TO HAVE GUSTS 40 TO 50 MPH.
NEXT ROUND OF RAIN ARRIVE LATE TONIGHT INTO SATURDAY, WITH RAIN TO
THE COAST BY 6 AM, AND SPREADING INLAND THROUGH EARLY TO MID SATURDAY
MORNING. MAIN SURFACE SLOW WITH THIS FRONT WILL REMAIN WELL OFFSHORE
AS IT MOVES TOWARDS VANCOUVER ISLAND. AS IT DOES, WILL PUSH A FRONT
TO THE COAST BY LATE MORNING, WITH THAT FRONT MOVING INLAND QUICKLY
IN THE AFTERNOON. SO, RAIN WILL TRANSITION TO SHOWERS BEHIND THE
FRONT. RAINFALL NOT ALL THAT IMPRESSIVE WITH THIS SYSTEM, WITH MOST
AREAS GETTING 0.25 TO 0.50 INCH, AND 0.50 TO 1.00 ACROSS THE COAST
RANGE/WILLAPA HILLS. NOT ALL THAT CONCERNED ABOUT SNOW, AS SNOW
LEVELS REMAIN AT OR ABOVE 6500 FT, WITH 4 TO 8 INCHES IN THE HIGHER
ELEVATIONS. AS SUCH, PASSES WILL REMAIN WET, WITH JUST RAIN.
SHOWERS CONTINUES SATURDAY NIGHT INTO EARLY SUNDAY, BUT, THE NEXT IN
THE SERIES OF FRONTS WILL ARRIVE ON SUNDAY. LOOKS TO BE VERY WET DAY,
WITH 0.25 TO 0.50 INCH FOR MOST INLAND AREAS, WITH A 0.50 TO 1.00
INCH FOR THE COAST, AND 0.75 TO 1.50 INCHES FOR THE COAST RANGE AND
WILLAPA HILLS. AT THIS TIME THIS WOULD NOT CAUSE ANY FLOODING, THOUGH
ENOUGH TO CAUSE SOME PONDING OF WATER IN AREA WITH POOR DRAINAGE,
LIKE LEAF-CLOGGED DRAINS AND LOW-LYING SPOTS. /ROCKEY
LONG TERM...(MONDAY THROUGH THURSDAY)
AFTER A TRANSIENT RIDGE ON
MONDAY ANOTHER SYSTEM LIKELY MOVES OVERHEAD COME TUESDAY. AFTERWARDS,
IT'S A RINSE AND REPEAT OF THIS PATTERN WITH A TROUGH FEATURE MOVING
WSW TO ENE INTO WESTERN CONUS EVERY 24-48 HOURS THROUGH THE END OF
THE WEEK. STILL, MODELS HAVE NOT SETTLED DOWN ENOUGH TO PIN POINT
DETAILS AT THIS TIME, WITH DIFFERENCES IN STRENGTH OF THE LOWS, AND
THE EVENTUAL STORMS TRACKS. IF THEY ARE FARTHER OFFSHORE, OR MOVE
MORE NORTHWARD, THEN COULD SEE LESS RAIN AND WIND. BUT, IF THEY MOVE
CLOSER TO THE PACIFIC NW, THEN MORE RAIN AND WINDS COULD BE LIKELY.
AS OF NOW, JUST HAVE TO GO WITH THE OVERALL TRENDS, WITH SOME
POTENTIAL OF HEAVY RAIN (AND HIGH ELEVATION SNOW) FOR MID TO LATE
NEXT WEEK.
FINER DETAILS LIKE THE SURFACE LOW PRESSURE PLACEMENT ASSOCIATED WITH
A STRONG SYSTEM SLATED FOR THE WED/THU TIME PERIOD WILL DETERMINE OUR
LOCAL IMPACTS. FOR EXAMPLE, RIVER FLOODING IS HIGHLY DEPENDENT ON OUR
RAINFALL FORECAST, AND THE QPF FORECAST IS DEPENDENT ON THE LOW
TRACK. SAME GOES WITH DETERMINING POTENTIAL FOR STRONG WINDS. AT THIS
TIME, CONFIDENCE STILL REMAINS LOW TO MODERATE FOR THESE IMPACTS. THE
LATEST HEFS GUIDANCE SUGGESTS A 15-35% CHANCE THAT RIVERS ALONG THE
COAST/COAST RANGE REACHING FLOOD STAGE LATER NEXT WEEK. SNOW LEVELS
WILL RAIN MAINLY NEAR OR ABOVE THE PASSES, RUNNING 4000 TO 7000 FEET,
THE HIGHEST SNOW LEVELS WILL OCCUR AHEAD OF FRONTAL PASSAGES.
/ROCKEY/ALVIZ
AVIATION
CONDITIONS ARE GENERALLY VFR ACROSS THE REGION EARLY
THIS MORNING ALTHOUGH THERE ARE SOME POCKETS OF PATCHY FOG
SLOSHING AROUND THE TUALATIN VALLEY AND PORTIONS OF THE WILLAMETTE
VALLEY (KEUG). ANY FOG LIKELY LIFTS AS THE MORNING GOES ON THANKS
TO INCREASING MID TO HIGH CLOUD COVER. LATER THIS MORNING INTO
MIDDAY HOURS A DECAYING FRONTAL BOUNDARY IS EXPECTED TO BRING A
LIGHT BAND OF MOISTURE TO REGION, MAINLY AT THE COAST AND BETWEEN
20-00Z. THERE'S A CHANCE LIGHT PRECIPITATION MAKES IT TO THE I-5
CORRIDOR BUT ALL TERMINALS SHOULD JUST REMAIN VFR. WINDS LIKELY
STAY BELOW 10-15 KNOTS AT ALL SITES EXCEPT FOR GUSTY EASTERLY
WINDS AT TTD AND SOUTHERLY WINDS ALONG THE COAST.
PDX AND APPROACHES...VFR CIGS/VIS CONTINUES THROUGH THE TAF PERIOD
WITH PERSISTENT EASTERLY WINDS COMING FROM THE COLUMBIA RIVER
GORGE. OFF CHANCE(15-25%) FOR LIGHT RAIN AT TIMES AFTER 20-22Z AS
A WEAK FRONT PASSES THROUGH, THOUGH CIGS REMAIN VFR THROUGHOUT.
NOT EXPECTING RAIN TO BE A PREVAILING CONDITION SO IT WAS EXCLUDED
FROM THE 12Z TAF. -SCHULDT
MARINE
ACTIVE CONDITIONS CONTINUE THE NEXT WEEK AND BEYOND AS
A BROAD LOW PRESSURE REMAINS OVER THE NE PACIFIC STEERING A PARADE
OF FRONTAL BOUNDARIES INTO THE COAST WATERS EVERY 24-36HRS.
ONE OF THESE AFOREMENTIONED FRONTS IS SLATED TO ARRIVE THIS
MORNING LIKELY BRINGING GALES TO THE OUTER WATERS THROUGH THE
AFTERNOON HOURS. AFTER A BRIEF LULL, ALBEIT WITH LIKELY LINGERING
HAZARDOUS SEAS FOR AT LEAST THE OUTER WATERS, PERIODS OF GALES
ARE EXPECTED BOTH SATURDAY AND SUNDAY. MODELS HAVE BACKED OFF
SLIGHTLY FOR STORM FORCE GUSTS ON SUNDAY BUT THERE'S STILL AN
OUTSIDE CHANCE (20%) FOR WINDS TO REACH INTO THIS CATEGORY. AS
NUMEROUS FRONTAL SYSTEMS CONTINUE TO TRAVERSE THE WATERS EARLY
NEXT WEEK, A LARGE AND ENERGETIC WESTERLY SWELL WILL CONTRIBUTE TO
LARGE AND CHAOTIC SEAS GOING FORWARD. EXPECT SEAS TO REMAIN IN
THE MID TO UPPER TEENS FROM SATURDAY THROUGH MUCH OF THE NEXT
WEEK, WITH SEAS POTENTIALLY BUILDING INTO THE 20-25 FT RANGE BY
MONDAY. EXPECT THE ASSOCIATED WITH WAVE PERIODS IN THE UPPER
TEENS TO NEAR 20 SECONDS EARLY NEXT WEEK AS WELL. MARINERS SHOULD
BE PREPARED FOR CONTINUED HAZARDOUS CONDITIONS THROUGH THE MIDDLE
TO END END OF NEXT WEEK. -SCHULDT/CB
BEACH HAZARDS
A LARGE, ENERGETIC WESTERLY SWELL WILL BUILD
OVER THE COASTAL WATERS AND BEGIN IMPACTING THE COASTLINE THIS
WEEKEND INTO EARLY NEXT WEEK. SEAS IN EXCESS OF 15 TO 20 FEET WITH
A PERIOD OF AROUND 20 SECONDS COULD RESULT AS BREAKING WAVES
APPROACHING 25 TO 30 FEET IN THE SURF ZONE. THUS A HIGH SURF
ADVISORY HAS BEEN ISSUED FOR SATURDAY MORNING THROUGH MONDAY
EVENING - LARGEST BREAKERS ON THE LATTER DAY. BEACHGOERS SHOULD
BE PREPARED FOR DANGEROUS SURF CONDITIONS AND LARGE WAVES RUNNING
FAR UP ONTO THE BEACH BEGINNING LATE SUNDAY AND CONTINUING THROUGH
EARLY NEXT WEEK.
-SCHULDT/CB
PQR WATCHES/WARNINGS/ADVISORIES
OR...HIGH SURF ADVISORY FROM 7 AM SAT TO 10 PM MON FOR ORZ101>103.
WA...HIGH SURF ADVISORY FROM 7 AM SAT TO 10 PM MON FOR WAZ201.
PZ...SMALL CRAFT ADVISORY TODAY THRU TONIGHT FOR PZZ210.
SMALL CRAFT ADVISORY TODAY THRU 6 AM SAT PZZ251>253.
SMALL CRAFT ADVISORY UNTIL 6 AM TODAY FOR PZZ271>273.
GALE WARNING TODAY FROM 6 AM TO 3 PM FOR PZZ271>273.
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