692
FXUS66 KPQR 181819 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1019 AM PST SAT JAN 18 2025
UPDATED AVIATION...
SYNOPSIS
HIGH PRESSURE IS EXPECTED TO REMAIN IN PLACE INTO
NEXT WEEK, MAINTAINING COOL TEMPS AND DRY CONDITIONS. EXPECT
HIGHS IN THE UPPER 30S TO LOW 40S AND LOW IN THE UPPER 20S TO
LOW 30S FOR INLAND VALLEY LOCATIONS INTO EARLY NEXT WEEK.
DISCUSSION...TONIGHT THROUGH FRIDAY
CONDITIONS LARGELY REMAIN
SIMILAR TO 24 HOURS AGO WITH RIDGING OFFSHORE AND TROUGHING
ACROSS MUCH OF THE CONTINENTAL US. NORTH WINDS AT THE SURFACE
HAVE BROUGHT IN COOLER, DRIER AIR INTO THE AREA, WHICH HASN'T
COMPLETELY ERODED STRATUS BUT HAS IMPROVED CEILINGS TO MVFR
ACROSS MUCH OF THE WILLAMETTE VALLEY. SHORT WAVE ENERGY DROPPING
SOUTHWARD OVER EASTERN OR/WA AND IDAHO IS HELPING LOWER THE
PRESSURE ON THE EAST SIDE OF THE CASCADES, SUPPORTING AN
INCREASING PRESSURE GRADIENT BETWEEN TROUTDALE AND THE DALLES.
TROUTDALE BRIEFLY REPORTED WEAK EASTERLY WINDS WHICH HAS
PARTIALLY BROKEN UP THE STRATUS AROUND MUCH OF THE METRO AREA.
MODELS SUPPORT THE INCREASING PRESSURE GRADIENT TODAY AND INTO
SUNDAY WITH A PEAK OF -3-5 MB EXPECTED LATE TONIGHT INTO SUNDAY
MORNING. THESE EASTERLY WINDS ARE EXPECTED TO HELP SCOUR OUR
THE STRATUS AROUND THE METRO THROUGH THE DAY, LEADING TO
SLIGHTLY HIGHER HIGHS THIS AFTERNOON IN THE NORTH VALLEY.
COLD OVERNIGHT LOWS ARE EXPECTED FROM SATURDAY NIGHT THROUGH MONDAY
NIGHT. LOWS BELOW FREEZING ARE EXPECTED WITH POSSIBLE MID 20S TO
VARYING PROBABILITIES EACH NIGHT. PROBABILITIES FOR 25 OR LOWER
TONIGHT ARE ON THE LOW SIDE AT 10-50% FOR THE WILLAMETTE VALLEY AND
LESS THAN 10% FOR THE PORTLAND/VANCOUVER METRO AS EASTERLY WINDS KEEP
THE AREA FROM DECOUPLING. SUNDAY NIGHT ODDS ARE A BIT HIGHER AT 20-
70% THOUGH THE METRO IS STILL NOT SHOWING A GOOD SIGNAL FOR TEMPS
REACHING 25 OR LOWER. PROBS AROUND THE HILLSBORO AREA ARE 30-40% BUT
NOTHING FARTHER EAST TOWARD DOWNTOWN. MONDAY NIGHT COULD BE THE MOST
WIDESPREAD FOR THE WILLAMETTE VALLEY WITH PROBS OF 30-70% AND 30% AS
FAR EAST AS BEAVERTON AND 20-30% IN VANCOUVER. COLD WEATHER
ADVISORIES ARE POSSIBLE BUT THE CONFIDENCE IS NOT QUITE THERE,
ESPECIALLY FOR TONIGHT. WOULD EXPECT HIGHER PROBS FOR SUNDAY AND
MONDAY NIGHTS WHICH ARE EXPECTED TO BE THE COLDEST.
LATER NEXT WEEK, THERE IS A 10-15% CHANCE THAT THE RIDGE WILL WEAKEN
AND INCREASING ZONAL FLOW WILL LEAD TO A SLIGHT CHANCE FOR LIGHT
PRECIPITATION WEDNESDAY FOR PRIMARILY SOUTHWEST WASHINGTON. WHILE
SNOW LEVELS APPEAR MOST LIKELY TO BE WELL ABOVE THE VALLEY FLOOR
THERE IS A 10% CHANCE THAT SNOW LEVELS START OFF INITIALLY NEAR SEA
LEVEL BEFORE QUICKLY RISING SO EVEN THE WORST CASE SCENARIO PRODUCES
FEW IMPACTS.
ENSEMBLE GUIDANCE CONTINUES TO REVEAL QUITE A BIT OF UNCERTAINTY
REGARDING THE LARGE SCALE WEATHER PATTERN AT THE END OF THE WEEK.
NONETHELESS, CONFIDENCE IS INCREASING THAT AT LEAST SOME LIGHT
PRECIPITATION WILL SPREAD INTO THE REGION NEXT FRIDAY. THE
PROBABILITY OF IT COMING IN AS VALLEY SNOW APPEARS TO BE LESS THAN
5% AT THIS POINT. -BATZ/CN
AVIATION
VISIBLE SATELLITE AS OF 18Z SAT SHOWS REMAINING
STRATUS MOSTLY CONFINED TO THE CENTRAL AND SOUTH WILLAMETTE VALLEY
FROM KSLE TO KEUG. A SMALL PATCH OF STRATUS AND FOG CENTERED OVER
KPDX IS QUICKLY ERODING, YIELDING VFR FOR TERMINALS NORTH OF
KSLE. EXPECT STRATUS DECK TO CONTINUE TO GRADUALLY ERODE FROM
NORTH TO SOUTH TODAY, WITH GUIDANCE CLEARING OUT KSLE 20-22Z AND
KEUG 22-00Z THIS AFTERNOON. DRIER NORTHERLY FLOW MAINTAINS VFR
ACROSS MOST OF THE AREA FOR THE REMAINDER OF THE TAF PERIOD. CLEAR
SKIES COULD YIELD PATCHY FOG DEVELOPMENT AFTER 12Z SUN IN MORE
SHELTERED SPOTS LIKE KHIO AND KEUG. OTHERWISE, PROBABILITY OF
IFR/LIFR CONDITIONS IS 10 PERCENT OR LESS AT ALL OTHER TERMINALS.
PDX AND APPROACHES...VFR EXPECTED THROUGH THE PERIOD AS LAST
REMAINING PATCH OF STRATUS AND FOG QUICKLY DISSIPATE AS OF 18Z
SAT. COULD SEE SOME PATCHY GROUND FOG TONIGHT INTO SUN MORNING,
BUT MODEL PROBABILITY FOR IFR/LIFR CONDITIONS IS BELOW 5 PERCENT.
/CB
MARINE
OFFSHORE WINDS GENERALLY BELOW 15-20 KT SATURDAY. WINDS
WILL BECOME MORE NORTHEASTERLY AS A THERMAL TROUGH RETURNS TO THE
OREGON COAST AND PERSISTS THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK. SEAS LIKELY HOVER AROUND 6 TO 9 FT THROUGH THE WEEKEND. A
LONG PERIOD SWELL IS EXPECTED TO PUSH INTO THE COASTAL WATERS ON
SATURDAY WITH A PERIOD OF AROUND 20 SECONDS, WITH SEAS LIKELY
REMAINING AROUND 7 TO 8 FT THROUGH SUNDAY. RELATIVELY QUIET
WEATHER CONTINUES INTO EARLY NEXT WEEK. ~HALL
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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