912
FXUS66 KPQR 190345 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
845 PM PDT SAT OCT 18 2025
UPDATED AVIATION DISCUSSION
SYNOPSIS
A ROBUST FRONTAL SYSTEM IMPACTS THE AREA THIS
EVENING INTO SUNDAY, BRINGING WIDESPREAD SOAKING RAIN TO THE
AREA WITH GUSTY SOUTHERLY WINDS. TRENDING DRIER SUNDAY NIGHT
INTO EARLY NEXT WEEK, ASIDE FROM THE SOUTH WA/NORTH OR COAST
WHERE LIGHT RAIN APPEARS INCREASINGLY LIKELY MONDAY NIGHT INTO
TUESDAY MORNING. A STRONGER WEATHER SYSTEM IS POSSIBLE LATE NEXT
WEEK, BRINGING HEAVIER RAIN AND THE POTENTIAL FOR IMPACTFUL
WIND GUSTS. HOWEVER, UNCERTAINTY REMAINS HIGH FOR EXACT WIND
GUSTS AND RAIN AMOUNTS.
DISCUSSION...SATURDAY AFTERNOON THROUGH FRIDAY
HIGH PRESSURE
REMAINS OVER NW OREGON AND SW WASHINGTON EARLY SATURDAY
AFTERNOON, THOUGH VISIBLE SATELLITE IMAGERY SHOWS CLOUDS
STREAMING INTO SW WASHINGTON AND FAR NW OREGON AHEAD OF THE NEXT
WEATHER SYSTEM APPROACHING THE REGION. UNDER HIGH PRESSURE THIS
AFTERNOON, TEMPERATURES ACROSS THE MAJORITY OF THE INTERIOR
LOWLANDS WILL WARM INTO THE 60S, NEAR 70 IN LANE COUNTY, THOUGH
THE AREAS ALREADY SEEING CLOUD COVER MAY ONLY WARM INTO THE
UPPER 50S.
THE SURFACE FRONTAL SYSTEM IS LEADING AHEAD OF THE PARENT UPPER
LOW WITH THIS INCOMING WEATHER SYSTEM. OBSERVATIONS INDICATE THE
WARM FRONT IS APPROACHING THE COAST NOW, BRINGING A ROUND OF
SHOWERS TO THE NORTH OREGON/SOUTH WASHINGTON COAST THIS
AFTERNOON, POSSIBLY PUSHING FURTHER EAST INTO SW WASHINGTON
THROUGH THE AFTERNOON HOURS. THE TRAILING COLD FRONT IS STILL
SLATED TO BRING A WIDESPREAD BAND OF STRATIFORM RAIN TO THE
ENTIRE REGION, BEGINNING ALONG THE COAST LATE THIS EVENING THEN
MOVING INLAND FROM NW TO SE OVERNIGHT INTO EARLY SUNDAY MORNING.
BEHIND THIS STRATIFORM BAND, CONDITIONS TURN TO SHOWERS THROUGH
TOMORROW EVENING. THIS IS WHEN FORECAST SOUNDINGS SHOW 850 MB
TEMPERATURES COOLING TO +1 TO +2 DEGREES CELSIUS, WITH SBCAPE
VALUES INCREASING TO 100-200 J/KG AND EQUILIBRIUM LEVELS
GENERALLY BELOW - 10 DEGREES CELSIUS. HOWEVER, 0-3 KM AGL BULK
SHEAR VALUES ARE FAIRLY HIGH AT 30-35 KT (HAVE OPTED TO USE 0-3
KM AGL BULK SHEAR VALUES INSTEAD OF 0-6 KM AS CLOUD TOPS
GENERALLY LOOK TO STAY NEAR OR BELOW 3 KM). BOTH SPEED SHEAR AND
DIRECTIONAL SHEAR ARE IN PLACE, AS THE WIND DIRECTION WILL VEER
WITH HEIGHT FOR A FEW HOURS OR SO AS THE UPPER LEVEL TROUGH
AXIS MOVES OVERHEAD LATE SUNDAY MORNING/EARLY AFTERNOON. THE
LIMITED INSTABILITY AND SHALLOW NATURE OF SUNDAY'S CONVECTION
SUGGESTS OVERALL LIGHTNING ACTIVITY WILL MOST LIKELY BE LIMITED
(WHICH HELPS EXPLAIN WHY NBM THUNDER PROBABILITIES ONLY PEAK
AROUND 15-25%). HOWEVER, WHETHER LIGHTNING OCCURS OR NOT,
STRONGER SHOWERS WILL HAVE THE POTENTIAL TO PRODUCE FUNNEL
CLOUDS, LANDSPOUTS, OR GUSTY OUTFLOW WINDS UP TO 45 MPH GIVEN
THE ENVIRONMENTAL WIND PROFILE IN PLACE, MEANING HIGHLY
LOCALIZED WIND DAMAGE IS POSSIBLE.
ADDITIONALLY, SOUTHERLY WINDS WILL BE BREEZY IN GENERAL
SATURDAY NIGHT AND SUNDAY AHEAD OF AND BEHIND THE COLD FRONT,
EVEN AWAY FROM SHOWERS AND THUNDERSTORMS. CURRENTLY EXPECTING
SOUTHERLY WIND GUSTS UP TO 25-30 MPH FOR INLAND AREAS, 30-40
MPH FOR THE SOUTH WA/NORTH OR COAST, AND UP TO 35-50 MPH IN THE
HIGH CASCADES. NOW WOULD BE A GOOD TIME TO SECURE ANY LOOSE
OUTDOOR OBJECTS YOU MAY HAVE. WINDS WILL WEAKEN SUNDAY NIGHT
WHILE ANY LINGERING SHOWERS BEGIN TO DISSIPATE.
ENSEMBLE GUIDANCE INDICATES MOSTLY ZONAL FLOW OVER THE AREA
MONDAY INTO TUESDAY, BRINGING MOSTLY DRY CONDITIONS AND SEASONAL
TEMPERATURES IN THE LOW 60S. THE ONLY EXCEPTION IS A 20-40%
CHANCE OF SHOWERS CONTINUING ALONG THE FAR N OREGON/S WASHINGTON
COAST. PRECIPITATION CHANCES INCREASE ON WEDNESDAY AS ENSEMBLES
INDICATE A SHORTWAVE WILL BRING A WEAKER FRONTAL SYSTEM THROUGH
THE AREA ON WEDNESDAY, BRINGING ANOTHER QUICK SHOT OF RAIN,
MAINLY TO THE COAST AND TERRAIN WITH LIMITED ACCUMULATION FOR
INLAND VALLEYS.
THE NEXT TIME PERIOD TO REALLY FOCUS ON IS THURSDAY INTO
FRIDAY AS ENSEMBLES INDICATE A MUCH MORE ROBUST WEATHER SYSTEM
COULD IMPACT THE PACNW. THERE IS HIGH CONFIDENCE AMONGST THE
ENSEMBLES IN A DEEP TROUGH PUSHING EAST FROM THE EASTERN PACIFIC
THURSDAY INTO THE WEEKEND, BRINGING ADDITIONAL RAIN AND
INCREASED WINDS TO THE AREA. HOWEVER, CONFIDENCE STILL REMAINS
LOW IN FORECAST SPECIFICS AND THEREFORE IMPACTS DUE TO A NUMBER
OF DIFFERENCES IN DEPTH, STRENGTH, AND TIMING OF THE TROUGH AND
ASSOCIATED SURFACE LOW. ULTIMATELY, THERE'S STILL THE POTENTIAL
FOR A DECENT AMOUNT OF RAIN BETWEEN 5 AM THURSDAY AND 5 AM
SATURDAY. NBM PROBABILITIES FOR 1+ INCH OF RAIN ARE 60-80%
FOR INLAND VALLEYS, 60-85% FOR THE CASCADES, AND 80-95% FOR THE
COAST. FOR 2 INCHES OF RAIN, PROBABILITIES ARE 20-45% FOR
INLAND VALLEYS, 30-60% FOR THE CASCADES, AND 50-85% FOR THE
COAST, WITH PROBABILITIES INCREASING FROM SOUTH TO NORTH. FOR 3
INCHES OF RAIN, PROBABILITIES ARE 5-15% FOR INLAND VALLEYS,
15-50% FOR THE CASCADES, AND 30-65% FOR THE COAST, WITH
PROBABILITIES AGAIN INCREASING FROM SOUTH TO NORTH. IF THE
HIGHER-END FORECAST VERIFIES, RIVER FLOODING IS NOT EXPECTED
AS RIVER LEVELS ARE CURRENTLY VERY LOW AND CAN HANDLE THE
RAINFALL. URBAN AREAS AND SMALL CREEK AND STREAMS COULD SEE
IMPACTS, THOUGH.
WHAT IS MORE OF A CONCERN IS THE POTENTIAL FOR HIGH WINDS WITH
THIS EVENT, ESPECIALLY ALONG THE COAST. ALONG THE COAST, NBM
INDICATES A 50-70% CHANCE OF WIND GUSTS 40+ MPH, A 35-50% CHANCE
OF WIND GUSTS 45+ MPH, A 20-40% CHANCE OF WIND GUSTS 50+ MPH,
AND A 10-20% CHANCE OF WIND GUSTS 55+ MPH. THE INTERIOR
LOWLANDS HAVE A 30-50% CHANCE OF WIND GUSTS 30+ MPH AND 5-20%
CHANCE OF WIND GUSTS 40+ MPH, HIGHEST IN THE CENTRAL WILLAMETTE
VALLEY. IF THE HIGHER WINDS MATERIALIZE ALONG THE COAST, EXTENSIVE
TREE DAMAGE AND POWER OUTAGES WOULD BE EXPECTED, ESPECIALLY
GIVEN HOW MANY TREES STILL HAVE FOLIAGE ON THEM.
LOOKING INTO THE WEEKEND, ANOTHER FRONTAL SYSTEM COULD CONTINUE
RAIN CHANCES WITH ANOTHER ROUND OF BREEZY WINDS POSSIBLE BOTH OF
WHICH COULD PRODUCE ACCUMULATING IMPACTS. KEEP AN EYE OUT ON
THE FORECAST OVER THE NEXT WEEK! -23/03
AVIATION
INCREASING WEST TO SOUTHWEST FLOW ALOFT TONIGHT AS AN
UPPER LEVEL TROUGH APPROACHES THE REGION. AS OF 03Z SUNDAY, A
SURFACE COLD FRONT IS PRODUCING MODERATE TO HEAVY RAIN ACROSS
NORTHERN PORTIONS OF THE AREA, WITH VISIBILITY REDUCTIONS TO
AROUND 2-3SM. CIGS AROUND FL050 WILL CONTINUE TO LOWER AS THE
FRONT PUSHES INLAND, WITH WIDESPREAD MVFR EXPECTED BY 08Z SUNDAY.
CONDITIONS AT THE COAST VERY LIKELY (80-90% CHANCE) TO DETERIORATE
TO AT LEAST MVFR BY 04-06Z SUNDAY. GUSTY SOUTH TO SOUTHWEST WINDS
WILL ALSO ACCOMPANY THE FRONTAL PASSAGE, WITH GUSTS UP 30 KT
EXPECTED AT THE COAST. WINDS WILL INCREASE INLAND AS WELL, WITH
GUSTS UP TO 20-25 KT LIKELY FOR ALL INLAND TAF SITES BETWEEN
06-12Z SUNDAY. THE FRONT IS EXPECTED TO PUSH THROUGH THE AREA BY
12Z SUNDAY, WITH SHOWERS DEVELOPING IN THE POST FRONTAL AIR MASS.
EXPECT PREDOMINATELY VFR CONDITIONS MIXED WITH OCCASIONAL MVFR.
THERE ALSO WILL BE A 15-20% CHANCE OF THUNDERSTORMS THROUGH SUNDAY
AFTERNOON.
KPDX AND APPROACHES...STEADY RAIN BRINGING REDUCED VISIBILITY AND
LOWERING CIGS. EXPECTED PREDOMINATELY MFR CONDITIONS THROUGH
11-12Z SUNDAY. SHOWERS BEHIND THE FRONTAL PASSAGE BRING A MIX OF
VFR AND MVFR CONDITIONS THROUGH SUNDAY AFTERNOON. EXPECT SOUTHWEST
WINDS TO INCREASE AS THE FRONT PUSHES CLOSER WITH GUSTS UP TO 20
KT. /DH
MARINE
A NORTHWESTERLY SWELL MOVING INTO THE WATERS FROM A
DYING SYSTEM OVER THE GULF OF ALASKA WILL BUILD SEAS TO AROUND
11-13 FT AT 13-14 SECONDS TONIGHT. IN ADDITION, THE NEXT FRONTAL
SYSTEM WILL PUSH THROUGH, RETURNING BREEZY SOUTHERLY WINDS WITH
GUSTS TO 25-30 KT. OCCASIONAL GALE-FORCE WIND GUSTS UP TO 35 KT
ARE POSSIBLE ACROSS THE COLUMBIA RIVER BAR AND NORTHERN/CENTRAL
INNER WATER ZONES (CAPE SHOALWATER TO CAPE FOULWEATHER) FROM 2000
SAT TO 0200 SUN, DURING THE FRONTAL PASSAGE. SMALL CRAFT
ADVISORIES REMAIN IN EFFECT THROUGH 0800 SUNDAY. WINDS WILL
SHIFT MORE WESTERLY BEHIND THE FRONT SUNDAY MORNING AND REMAIN
BREEZY. HOWEVER, SEAS WILL CONTINUE TO BUILD FROM THIS CURRENT
SYSTEM, LIKELY RISING ABOVE 15 FT AFTER 1100 SUN. SEAS ARE
FORECAST TO PEAK BETWEEN 15 TO 20 FT SUNDAY AFTERNOON; THEREFORE,
A HAZARDOUS SEAS WARNING IS IN EFFECT FOR ALL WATERS INCLUDING THE
COLUMBIA RIVER BAR FROM 0800 SUNDAY TO 0500 MONDAY. CHANCES FOR
SEAS ABOVE 20 FT REMAIN LESS THAN 10%, EXCEPT OVER THE NORTHERN
OUTER WATERS FROM 40 TO 60 NM OFFSHORE WHERE THERE IS A 40-60%
CHANCE FOR SEAS OVER 20 FT.
SEAS WILL DECREASE LATER MONDAY INTO TUESDAY MORNING, BOTTOMING
OUT AROUND 7-9 FT AT 12-13 SECONDS BEFORE ANOTHER POTENT
NORTHWESTERLY SWELL ARRIVES TUESDAY AFTERNOON AND EVENING PUSHING
SEAS UP TO AROUND 15-16 FT RANGE AGAIN. AN ACTIVE WEATHER PATTERN
IS THEN EXPECTED TO CONTINUE LATE WEDNESDAY THROUGH FRIDAY NIGHT
WITH A PERIOD OF STORM FORCE WIND GUSTS OF 48 KT OR STRONGER
POSSIBLE (20-30% CHANCE ACROSS ALL WATERS INCLUDING THE COLUMBIA
RIVER BAR THURSDAY AND FRIDAY). -10/23
BEACH HAZARDS
A NORTHWESTERLY SWELL OF 15-18 FT AT 15-16
SECONDS IS FORECAST TO ENTER THE WATERS ON SUNDAY. THIS INCREASE
IN WAVE ENERGY WILL SUPPORT A HIGH THREAT FOR SNEAKER WAVES ON
SUNDAY. A BEACH HAZARDS STATEMENT REMAINS IN EFFECT ACROSS THE
CENTRAL AND NORTHERN OREGON COAST AND THE SOUTH WASHINGTON COAST
THROUGH SUNDAY EVENING. SNEAKER WAVES CAN RUN UP SIGNIFICANTLY
FARTHER ON A BEACH THAN NORMAL, INCLUDING OVER ROCKS, LOGS, AND
JETTIES. SNEAKER WAVES CAN SUDDENLY KNOCK PEOPLE OFF OF THEIR FEET
AND QUICKLY PULL THEM INTO THE OCEAN WHICH MAY LEAD TO SERIOUS
INJURY OR DROWNING. CAUTION SHOULD BE USED WHEN IN OR NEAR THE
WATER. ALWAYS KEEP AN EYE ON THE WAVES, AND BE ESPECIALLY WATCHFUL
OF CHILDREN AND PETS. REMEMBER, NEVER TURN YOUR BACK ON THE
OCEAN! -10/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 8 AM PDT SUNDAY FOR PZZ210-251>253-
271>273.
HAZARDOUS SEAS WARNING FROM 8 AM TO 11 PM PDT SUNDAY FOR PZZ210.
HAZARDOUS SEAS WARNING FROM 8 AM SUNDAY TO 5 AM PDT MONDAY FOR
PZZ251>253-271>273.
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