204
FXUS66 KPQR 241216
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
416 AM PST TUE FEB 24 2026
SYNOPSIS
AN ATMOSPHERIC RIVER EVENT KEEPS CONDITIONS RATHER
WET TO START THE DAY WITH WEATHER RELATED IMPACTS STAYING MINOR.
WEDNESDAY THROUGH THE END OF THE WORK WEEK THE WEATHER PATTERN
APPEARS FAIRLY BENIGN WHILE TRENDING DRIER, AT LEAST FOR THE
INLAND VALLEYS. WE'LL NEED TO WATCH A SYSTEM UNDERCUTTING THE
REGION TO THE SOUTH OVER THE WEEKEND BUT THE WEATHER TRENDS DRY
AGAIN EARLY NEXT WEEK. CONDITIONS LIKELY REMAIN WITHIN OUR
TYPICAL CLIMATOLOGICAL NORMS THROUGH THE FORECAST PERIOD WITH NO
SIGNIFICANT WEATHER IMPACTS ON THE HORIZON.
SHORT TERM...NOW THROUGH WEDNESDAY
THIS MORNING SATELLITE AND
RADAR OBSERVATIONS SHOW OUR ATMOSPHERIC RIVER CONTINUING TO
STREAM PRECIPITATION AND MOISTURE OVERHEAD THANKS TO AN EXTREMELY
ELONGATED UPPER-LEVEL TROUGH OVER THE EASTERN PACIFIC. A
SURFACE ANALYSIS CURRENTLY SHOWS A QUASI-STATIONARY FRONTAL
BOUNDARY DRAPED WSW TO ENE ACROSS WESTERN OREGON AS WELL,
GENERALLY HOLDING IN PLACE INTO THE MIDDAY HOURS BEFORE IT
FINALLY BEGINS TO SHIFT SOUTHEASTWARD. AS THIS PROGRESSION
BEGINS TO OCCUR THIS MORNING, STRATIFORM/STEADIER RAIN WILL
BECOME MORE INTERMITTENT AND SPORADIC ACROSS NW OREGON AND SW
WASHINGTON IN THE WAKE OF THE SHIFTING FRONT. WE'VE SEEN DECENT
24 HOUR RAINFALL TOTALS SO FAR WITH THIS EVENT: 1.00-1.30 INCHES
IN THE PORTLAND METRO THROUGH ALBANY, WITH 2.00-3.00 INCHES
NEAR EUGENE AND ACROSS PORTIONS OF THE OREGON CASCADE AND COAST
RANGE. PORTLAND, SALEM, AND EUGENE ALL HIT THEIR RECORD DAILY
MAXIMUM RAINFALL FOR FEB 23RD, SO RAINFALL AMOUNTS HAVE BEEN
NOTEWORTHY. FORTUNATELY, WHILE THERE HAVE BEEN RISES ON RIVERS
AND A FEW ISOLATED LANDSLIDES, WATER PONDING ON ROADWAYS, ETC.
IMPACTS HAVE BEEN AND WILL STAY FAIRLY LIMITED/MINOR BEFORE
CONDITIONS QUIET DOWN INTO THE MIDDLE OF THE WEEK.
IT'S WORTH POINTING OUT AN EASTERLY PRESSURE GRADIENT PULLING
SLIGHTLY COOLER AIR UP INTO THE LEE SIDE SIDE OF THE CASCADES
JUST NORTH OF THE PREVIOUSLY MENTIONED SURFACE FRONT IN
COMBINATION WITH NEARLY STEADY PRECIPITATION HAS LEAD TO A
LOCALIZED AREA OF DYNAMIC COOLING AND ISOTHERMAL SNOWFALL IN
THE UPPER HOOD RIVER VALLEY. TEMPERATURES IN THIS LOCALIZED
REGION ARE 32-34 DEGREES AS OF 0400 AND HAVE TICKED HIGHER SINCE
WET SNOW HAS LIGHTENED - THIS'LL FURTHER COME INTO PLAY IN A
SECOND. WHILE MANY HIGH RESOLUTION MODELS ARE STRUGGLING TO
RESOLVE THIS ONGOING WINTRY PRECIPITATION (AND WHIFFED LEADING
UP THE SNOWFALL), THE LATEST HRRR SUGGESTS WET SNOW OR A
RAIN/SNOW MIX CONTINUES UNTIL 9-10AM, AFTER WHICH POINT A
FURTHER LIGHTENING IN PRECIPITATION COUPLED WITH WEAK WARM
ADVECTION SHOULD BRING AN END TO ISOTHERMAL SNOWFALL. A WINTER
WEATHER ADVISORY REMAINS IN EFFECT FOR THE UPPER HOOD RIVER
VALLEY UNTIL 10AM - BE PREPARED TO WINTER DRIVING CONDITIONS IN
THIS AREA TO START THE DAY.
TONIGHT INTO WEDNESDAY, THE LONGWAVE TROUGH PRODUCING THE
CURRENT AR ACTUALLY CUTS OFF INTO A CLOSED LOW AND RETROGRADES
WESTWARD INTO THE PACIFIC WHILE FLOW OVER THE PACNW BECOMES
MORE ZONAL. SCATTERED SHOWERS WILL CONTINUE THROUGH WEDNESDAY AS
A WEAK SHORTWAVE MOVES SOUTHEAST THROUGH WA AND OR. MOST AREAS
ARE EXPECTED TO DRY OUT BY LATE WEDNESDAY WITH PRECIPITATION
CHANCES MAINLY LIMITED TO THE FAR NORTH OREGON COAST, COAST
RANGE, AND CASCADES AND SW WASHINGTON. A RATHER HO-HUM END TO
OUR SOGGY SAGA. -99/03
LONG TERM...THURSDAY THROUGH MONDAY
COLDER AIR IS EXPECTED
TO BE FUNNELED INTO THE PACNW BEHIND WEDNESDAY'S SHORTWAVE. THIS
ALONG WITH CLEARING SKIES WILL LEAD TO COLDER OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT WITH A 60-90% CHANCE OF LOW
TEMPERATURES THURSDAY MORNING FALLING BELOW FREEZING IN THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY AND A 40-60% CHANCE FOR
THE SW WASHINGTON LOWLANDS. THESE TEMPERATURES ARE LARGELY
CLEARING DEPENDED AND ADDED CLOUD COVER WOULD KEEP LOWS HIGHER
THAN FORECAST. THERE'S AN OFF CHANCE (~5-10%) AN ISOLATED SHOWER
WANDERS OFF THE COAST RANGE OR WILLAPA HILLS INTO THE SOUTHWEST
WASHINGTON LOWLANDS DURING THIS PERIOD WHICH WOULD HAVE THE
POTENTIAL TO BE A RAIN/SNOW MIX ASSUMING PRECEDING CLEARING
HEADED INTO THE SUNRISE HOURS THURSDAY. HOWEVER, A LOT OF
VARIABLES WOULD HAVE TO PERFECTLY ALIGN FOR THIS TO OCCUR. SO
WHILE THE FORECAST MAY INTRODUCE A MENTION OF A SLIGHT CHANCE
(15%) FOR RAIN/SNOW LATE WEDNESDAY NIGHT INTO THURSDAY MORNING,
IT IS EXTREMELY UNLIKELY YOU'LL SEE ANY IMPACTS BELOW
1500-2000FT - IN FACT YOU'LL BE LUCKY TO SEE ANYTHING AT ALL.
ENSEMBLE GUIDANCE INDICATES ZONAL FLOW PERSISTS THURSDAY
THROUGH THE WEEKEND. LOW PRECIPITATION CHANCES CONTINUE ACROSS
THE AREA EACH DAY, MAINLY OVER THE TERRAIN, WITH LIMITED
ACCUMULATION EXPECTED. THE CLOSED LOW REMNANT FROM THE CURRENT
LONGWAVE TROUGH IS SLATED TO MOVE BACK EAST TOWARDS THE WEST
COAST LATE WEEKEND TO EARLY NEXT WEEK. MOST ENSEMBLE MEMBERS
SUGGEST IT WILL MOVE INLAND ALONG THE CA COAST, BUT EXACTLY HOW
FAR NORTH OR SOUTH IS UNCERTAIN. THIS UNCERTAINTY IS PART OF THE
REASON FOR THE LOW PRECIPITATION CHANCES AS A TRACK FURTHER
NORTH WOULD YIELD BETTER CHANCES FOR PRECIPITATIION.
HOWEVER, THE JET STREAM ALONG THE ZONAL FLOW IS EXPECTED TO DIP
SOUTH INTO CENTRAL OR, WHICH WOULD ALLOW FOR COLDER AIR TO
IMPACT THE AREA ONCE AGAIN SATURDAY NIGHT AND SUNDAY NIGHT INTO
EARLY NEXT WEEK. THERE'S A 30-60% CHANCE OVERNIGHT TEMPERATURES
FALL BELOW FREEZING AGAIN EACH NIGHT FOR THE LOWLANDS OUTSIDE
OF THE PORTLAND METRO AREA. SIMILAR TO THURSDAY MORNING, A
RAIN/SNOW MIX MAY SHOW UP IN THE FORECAST FOR LOWER ELEVATIONS
THAT HAVE A CHANCE OF PRECIPITATION, BUT THERE IS LESS THAN 5%
CHANCE OF ACCUMULATING SNOW. -99/03
AVIATION
EARLY THIS MORNING, OUTSIDE OF KAST (VFR), CONDITIONS
ARE A MIX OF MVFR TO LIFR AS A WEATHER SYSTEMS KEEPS RAIN
STREAMING OVERHEAD. HIGH CONFIDENCE (>90% CHANCE) FOR AT LEAST
MVFR CIGS TO STAY IN PLACE ACROSS THE MAJORITY OF TERMINALS TODAY
THROUGH THE REMAINDER OF THE TAF PERIOD. AGAIN KAST IS THE
EXCEPTION WHERE CIGS HOLD LARGELY VFR AS THE HEAVIEST RAIN IS
FURTHER SOUTH. THERE IS ALSO A 50-90% CHANCE FOR EVERYWHERE ELSE
TO SEE IFR CIGS THROUGH 17-20Z, AFTER WHICH POINT THESE
PROBABILITIES LOWER TO 20-50%. MODERATE RAIN THIS MORNING MAY
RESULT IN VIS REDUCTIONS TO 3-5 SM AT ANY GIVEN TERMINAL. AT LEAST
AFTER 14-18Z TODAY, RAIN WILL DECREASE AND TRANSITION TO SHOWERS.
DRIER CONDITIONS RETURN THIS EVENING AND OVERNIGHT. WINDS
GENERALLY STAY BELOW 10 KNOTS THROUGH THE TAF PERIOD AT ALL
TERMINALS.
KPDX AND APPROACHES...CURRENTLY SITTING AT IFR CIGS AND VIS EARLY
THIS MORNING WITH OUR FIRST CHANCE FOR APPLICABLE IMPROVEMENT
AROUND 16-17Z WHEN STEADIER RAIN BEGINS TO TRANSITION TO SHOWERS
LOCALLY - LOW TO MODERATE CONFIDENCE IN THIS TIMING FOR A
TRANSITION BACK TO MVFR. EVEN THROUGH THE AFTERNOON WE'LL HOLD
ONTO A 25-30% CHANCE FOR IFR CIGS TO PERSIST. -99
MARINE
SEAS AND WINDS CONTINUE TO TREND DOWN TODAY AND
THROUGH THE MIDDLE OF THE WEEK. SEAS REMAIN STEEP THROUGH
TONIGHT WITH A HAZARDOUS SEAS WARNING REMAINING IN EFFECT UNTIL
7 PM TODAY BEFORE TRANSITION TO A SMALL CRAFT ADVISORY WHICH IS
IN EFFECT UNTIL 10 AM TUESDAY. THE PATTERN IS EXPECTED TO REMAIN
BENIGN THROUGH THURSDAY BEFORE A WNW SWELL ENTERING THE WATERS
FRIDAY MORNING PUSHES SEAS TO AROUND 10 FEET WITH A PERIOD IN
THE MID TEENS. -19
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR
ORZ121.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 10 AM PST THIS MORNING FOR PZZ210-
251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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