720
FXUS66 KPQR 191825 AAB
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1025 AM PST WED FEB 19 2025
UPDATED SHORT TERM, LONG TERM, AVIATION, HAZARDS.
SYNOPSIS
RAIN CONTINUES THROUGH TODAY AS A FRONTAL SYSTEM
PUSHES ACROSS THE REGION. WINDS ALONG THE COAST WILL CONTINUE TO
DECREASE THIS MORNING/AFTERNOON WITH PEAK WINDS ALONG THE
BEACHES AND HEADLANDS. INLAND WIND GUSTS WILL REMAIN BELOW 30
MPH. SNOW WILL RETURN TO THE CASCADES THROUGH EARLY THURSDAY
MORNING WITH AROUND 4 TO 8 INCHES OF SNOW EXPECTED AT PASS
LEVEL. TRENDING DRIER AND SLIGHTLY WARMER THURSDAY INTO FRIDAY.
HIGH CONFIDENCE IN STRONG FRONTAL SYSTEM THIS WEEKEND WITH THE
POTENTIAL FOR ATMOSPHERIC RIVER CONDITIONS.
SHORT TERM...NOW THROUGH THURSDAY
A FRONTAL SYSTEM CONTINUES
TO MOVE EAST THROUGH THE AREA, BRINGING WIDESPREAD RAIN THROUGH
THE REGION UNTIL EARLY THURSDAY MORNING. EXPECT TOTAL RAINFALL
ACCUMULATIONS AROUND 0.25 TO 0.50 INCH IN THE VALLEY LOWLANDS,
0.50 TO 0.75 INCH ALONG THE COAST, AND 1.00 TO 1.25 INCH IN THE
COAST RANGE AND CASCADE FOOTHILLS. LATEST PROBABILISTIC GUIDANCE
SUGGESTS A 40-50% CHANCE TO EXCEED 0.50 INCH FOR THE VALLEY
LOWLANDS, A 40-50% CHANCE TO EXCEED 0.75 INCH ALONG THE COAST,
AND 30-50% CHANCE TO EXCEED 1.25 INCH IN THE COAST RANGE AND
CASCADE FOOTHILLS.
SNOW RETURNS TO THE CASCADES, WITH 4 TO 8 INCHES MORE SNOW
ACCUMULATION EXPECTED THROUGH EARLY THURSDAY MORNING (HEAVIEST
DURING LATE WEDNESDAY WITH THE BULK OF THE FRONT). GUIDANCE HAS
TRENDED LOWER IN PROBABILITIES, WITH NBM SUGGESTING A 20-40%
CHANCE TO EXCEED 4 INCHES OF SNOWFALL, AND HREF SUGGESTING A
40-60% CHANCE TO EXCEED 6 INCHES BY EARLY THURSDAY MORNING.
WHILE GUIDANCE PROBABILITIES HAVE LOWERED, THE EXPECTED RANGE OF
SNOWFALL ACCUMULATIONS WILL STILL LIKELY BE IMPACTFUL TO
CASCADE PASSES. AS A RESULT, WILL MAINTAIN THE CURRENT WINTER
WEATHER ADVISORY FOR THE CASCADES, WHICH IS CURRENTLY SET TO END
ON 4 AM THURSDAY.
WINDS ALONG THE COAST BEGIN TO INCREASE THIS MORNING BUT HAVE
NOT NECESSARILY MATCHED THE WINDS OVER THE WATERS. AROUND
CLATSOP SPIT WINDS ARE GUSTING TO NEAR 40 MPH, BUT ELSEWHERE,
GUSTS UP TO 25 MPH ARE MORE COMMON. INLAND LOCATIONS (GENERALLY
IN THE WILLAMETTE VALLEY) WILL ALSO SEE ELEVATED SOUTHERLY
WINDS BUT WILL BEGIN TO EASE IN THE AFTERNOON. THE COLUMBIA
RIVER GORGE WILL EXPERIENCE WESTERLY WINDS UP TO 25 MPH ASSIDE
FROM MORE ELEVATED LOCATIONS THAT WOULD BE CLOSER TO 40 MPH. TO
GIVE SOME CONTEXT, THESE INCREASED EASTERLY WINDS IN THE GORGE
ARE SUPPORTED BY PRESSURE GRADIENT FROM TROUTDALE TO THE DALLES
OF AROUND -5 TO -6 MB WHICH FAVORS WINDS AROUND 35 MPH.
BY THURSDAY, THE PATTERN ALOFT BECOMES MORE MESSY WITH WEAK
RIDGING WHICH WILL KEEP CONDITIONS FAIRLY DRY WITH MAYBE A FEW
SPITS OF SHOWERS HERE OR THERE.-MUESSLE/HALL
LONG TERM...FRIDAY THROUGH TUESDAY
MOST CLUSTERS KEEP THE
AREA DRY ON FRIDAY, ALTHOUGH THERE IS AROUND A 40% CHANCE THAT A
FRONT IS ABLE TO PUSH RAIN BACK INTO SOUTHWEST WASHINGTON AND
FAR NW OREGON BY FRIDAY AFTERNOON. TEMPERATURES ARE LIKELY TO
CONTINUE THE GRADUAL WARMING TREND INTO THE MID TO UPPER 50S
INTO THE WEEKEND AND EARLY NEXT WEEK.
RAIN SHOWERS LATE FRIDAY INTO SATURDAY TURNS TO HEAVIER RAIN
SUNDAY AS THE NEXT WEATHER SYSTEM WILL MOVE IN. THIS SYSTEM IS
ASSOCIATED WITH AN ATMOSPHERIC RIVER THAT IS MOVING THROUGH THE
REGION, THOUGH THE LOCATION OF IT'S SETUP LACKS CERTAINTY. IT
HAS SHIFTED OVER THE LAST FEW DAYS WITH IT TRENDING FURTHER
SOUTH. THIS MEANS THAT RAIN AND WIND WOULD BE LESS, BUT OVERALL
IT IS TRENDING TOWARDS A MODERATE TO STRONG ATMOSPHERIC RIVER
OVERALL. WILL CONTINUE TO MONITOR, BUT RAINFALL TOTALS WILL BE
HIGH IN ALL LOCATIONS, BUT ESPECIALLY THROUGH THE COAST AND
COAST RANGE. BOTH THE GEFS AND THE EUROPEAN ENSEMBLE SUGGESTS
MEAN PWAT AMOUNTS OF AROUND 1.1-1.2 INCH NOW. EVEN WITH THE RAIN
AND THE SNOW FROM LAST WEEK, LATEST HEFS FORECASTS SHOW A 5-15%
CHANCE OF LOCAL TRIBUTARY RIVERS REACHING MINOR FLOOD STAGE,
WILL NEED TO MONITOR THE FLASHIER RIVERS AS WE GET CLOSER TO
SUNDAY.
LOOKING INTO EARLY NEXT WEEK, RAIN WILL PERSIST OSCILATING
BETWEEN SHOWERY CONDITIONS BEHIND THE FRONT, AND A SECONDARY
FRONTAL SYSTEM LATE MONDAY INTO TUESDAY. THE FRONT IS ASSOCIATED
WITH A POTENTIAL LOW PRESSURE SYSTEM. HOWEVER, IT LACKS SUPPORT
ALOFT AS THE EC AND CANDIAN MODELS ARE NOT QUITE LATCHING ONTO
THE LOW FORMING. -MUESSLE/DH
AVIATION
MIXED MVFR CIGS AND MVFR/VFR VIS ONGOING AS COLD
FRONTAL RAIN SHOWERS TRACK EASTWARD ACROSS THE REGION. WINDS HAVE
LARGELY SHIFTED OUT OF THE SOUTH TO SOUTHWEST AT 10-15 KT GUSTING
UP TO 20 KT ACROSS THE REGION, ASIDE FROM PDX/TTD WHERE COLUMBIA
GORGE OUTFLOW HAS MAINTAINED EAST TO SOUTHEAST WINDS AT 10-15 KT
GUSTING 20-25 KT. GUSTY EAST FLOW WILL BENEATH SOUTHWESTERLY FLOW
AT 2 KFT IS YIELDING MARGINAL LOW-LEVEL WIND SHEAR AT TTD, HOWEVER
HAVE EXCLUDED MENTION AS SURFACE WINDS WEAKEN AND TURN IN THE
NEXT 1-3 HOURS. AS THE FRONTAL BOUNDARY PROGRESSES EASTWARD, WINDS
WILL ULTIMATELY TURN SOUTHWESTERLY TO WESTERLY AT ALL TERMINALS,
WITH SPEEDS DECREASING BELOW 5-10 KT AFTER 00-06Z THU. RAIN
SHOWERS WILL DIMINISH IN COVERAGE AFTER 21-24Z WED, RESULTING IN
ANY RESTRICTED VSBYS/CIGS TO TREND UPWARD TO VFR.
PDX AND APPROACHES...CONTINUED MVFR CIGS/VIS EXPECTED DURING
LIGHT RAIN SHOWERS THROUGH 21-24Z WED, BEFORE IMPROVING TO VFR
DURING DIMINISHED SHOWER COVERAGE AFTER 00Z THU. EAST TO SOUTHEAST
WINDS AT 10-15 KT WITH OCCASIONAL GUSTS NEAR 20 KT WILL TURN OUT
OF THE SOUTHWEST BEHIND THE COLD FRONTAL PASSAGE AFTER 21Z WED,
BEFORE SPEEDS DIMINISH TO 5 KT OR LESS AFTER 06Z WED. -PICARD
MARINE
A FRONTAL SYSTEM MOVING ONSHORE THROUGH THE AFTERNOON IS
RESULTING IN SOUTHERLY WIND GUSTS UP TO 45 KT ACROSS ALL WATERS.
THEREFORE, HAVE MAINTAINED THE CURRENT SUITE OF GALE WARNINGS
ACROSS ALL WATERS. HOWEVER, THE COLD FRONT LOOKS TO BE MOVING
SLIGHTLY FASTER THAN ORIGINALLY FORECASTED. SO, HAVE SHORTENED
THE GALE WARNING FOR THE INNER WATERS AND THEY ARE EXPECTED TO
SUBSIDE TOWARDS SMALL CRAFT CONDITIONS BY THIS AFTERNOON. SEAS 10
TO 14 FT THROUGH THE AFTERNOON AND WILL SLOWLY SUBSIDE TOWARDS 9
TO 11 FT BY TONIGHT AND REMAIN THERE THROUGH AT LEAST FRIDAY.
ANOTHER FRONTAL SYSTEM WILL ENTER THE WATERS LATE FRIDAY/SATURDAY
AND WILL LIKELY (45-60% PROBABILITY) OF SOUTHERLY GALE FORCE
GUSTS UP TO 45 KT. SEAS ARE ALSO EXPECTED TO BUILD TOWARDS 12 TO
14 FT. THERE IS STILL SOME UNCERTAINTY AS TO THE EXACT TIMING AND
STRENGTH, BUT MODELS ARE IN GOOD AGREEMENT WITH BOTH GALES AND SEA
HEIGHTS AT THIS TIME. -42
PQR WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 4 AM PST THURSDAY FOR ORZ126>128.
WA...WINTER WEATHER ADVISORY UNTIL 4 AM PST THURSDAY FOR WAZ211.
PZ...SMALL CRAFT ADVISORY UNTIL 1 AM PST THURSDAY FOR PZZ210-
251>253.
GALE WARNING UNTIL 4 PM PST THIS AFTERNOON FOR PZZ271>273.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 1 AM PST
THURSDAY FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
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