659
FXUS66 KPQR 232054
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
154 PM PDT MON MAR 23 2026
SYNOPSIS
OUR LATEST DRY STREAK COMES TO AN END ON TUESDAY AS
A FRONTAL SYSTEMS USHERS IN THE RETURN OF WIDESPREAD RAIN AND
BREEZY TO LOCALLY GUSTY SOUTH/SOUTHWEST WINDS - PAR FOR THE
COURSE GIVEN IT'S LATE MARCH. AFTER THE COLD FRONT PASSES TO
OUR EAST BY TUESDAY NIGHT, LINGERING SHOWERS PERSIST THROUGH
WEDNESDAY WITH AT LEAST SOME (2-5IN) MOUNTAIN SNOWFALL BEFORE
TAPERING OFF BY THURSDAY. HIGH CONFIDENCE IN DRY WEATHER WITH A
WARMING TREND LATE WEEK INTO THE WEEKEND. CHANCES INCREASING
FOR ANOTHER WEATHER SYSTEM LATE WEEKEND INTO EARLY NEXT WEEK,
HOWEVER, THE EXACT TIMING OF THIS LATER SYSTEM REMAINS NEBULOUS.
DISCUSSION...NOW THROUGH MONDAY
DRY CONDITIONS COUPLED WITH
AMPLE HIGH-CLOUDS CONTINUE THIS AFTERNOON THANKS TO AN UPPER-
LEVEL RIDGE OF HIGH PRESSURE OVER WESTERN CONUS BEGINNING TO
DEPART FURTHER EAST, THE SAME FEATURE RESPONSIBLE FOR THE
RATHER PLEASANT CONDITIONS THIS PAST WEEKEND. OUR FOCUS SHIFTS
TO THE NORTHEASTERN PACIFIC TONIGHT WHERE AN UPPER LEVEL LOW
PRESSURE SYSTEM IS EXPECTED TO STRENGTHEN, EVENTUALLY
SLINGSHOTTING A CLOSED SURFACE LOW PRESSURE SYSTEM ON IT'S
SOUTHERN PERIPHERY INTO WESTERN CANADA ON TUESDAY. THE COLD
FRONT ASSOCIATED WITH THIS SURFACE LOW STRETCHED SOUTH FROM
WESTERN CANADA TO OFFSHORE OF NORTHERN CALIFORNIA SWINGS INLAND
AS TUESDAY PROGRESSES PRODUCING WIDESPREAD RAIN AND BREEZY WINDS
FOR NW OR AND SW WA. EXPECT PERIODS OF MODERATE TO LOCALLY
HEAVY RAIN AT TIMES, MAINLY IN MIDDAY AND AFTERNOON HOURS, BUT
OVERALL TOTAL RAINFALL AMOUNTS ARE NOT EXPECTED TO PRODUCE ANY
FLOODING IMPACTS. 24 HOUR RAIN AMOUNTS FROM 5 AM TUESDAY TO 5 AM
WEDNESDAY ARE AROUND 0.25-0.50 INCH FOR THE INTERIOR LOWLANDS,
0.5-1 INCH ALONG THE COAST, 0.75-1.5 INCH FOR THE COAST RANGE,
WILLAPA HILLS, SW WA CASCADES, AND 0.5-1.0 INCH FOR THE OREGON
CASCADES.
WHILE RAINFALL DOESN'T LOOK PARTICULARLY IMPACTFUL, WE'LL HAVE
TO KEEP A CLOSE EYE ON WINDS WHICH ARE EXPECTED TO PEAK ALONG
THE COAST BETWEEN 8 AM TO 5 PM, AND INLAND BETWEEN 11 AM TO 6
PM. THE STRONGEST WINDS WILL BE ALONG THE COAST, COAST RANGE,
AND WILLAPA HILLS WHERE THE LATEST NBM SUGGESTS A 65-90% CHANCE
FOR MAXIMUM WIND GUSTS TO EXCEED 40 MPH BUT ONLY A 5-20% TO
EXCEED 50 MPH. HOWEVER, THE LATEST HIGH RESOLUTION GUIDANCE LIKE
THE 12Z HREF/REFS PRODUCES MUCH HIGHER GUSTS COMPARATIVELY
(MOST MEMBERS IN THE 55-60 MPH RANGE) RIGHT ALONG THE COAST, AND
WHILE THE HREF/REFS DOES TEND TO RUN "HOT" WHEN IT COMES TO
WIND GUSTS IN GENERAL, WINDS NEAR THE TOP OF THE BOUNDARY LAYER
AT ~850MB PEAK AROUND 50-65 KNOTS TUESDAY MORNING BEFORE
RAPIDLY DECREASING BEHIND THE FRONT TUESDAY AFTERNOON.
DETERMINISTIC MODEL SOUNDINGS FROM THE NAM/GFS/ECMWF REVEAL A
FAIRLY STABLE TEMPERATURE PROFILE ABOVE THE SURFACE WHICH WOULD
WORK AGAINST BROADER VERTICAL MIXING OF THESE WINDS ALOFT TO THE
SURFACE. THAT SAID, MORE CONVECTIVE ELEMENTS RIGHT ALONG THE
COLD FRONT MAY PROVIDE ENOUGH FORCING TO PUNCH THESE STRONGER
WINDS TO THE SURFACE, ALBEIT BRIEFLY/NON-UNIFORMLY. WOULD NOT
BE SURPRISED TO SEE A OBSERVATION OR TWO GUST AROUND 50-55MPH+
TUESDAY, PARTICULARLY CLATSOP COUNTY NORTHWARD ALONG THE SOUTH
WA COAST WHERE THIS FRONTAL FORCING IS MAXIMIZED, BUT THE LACK
OF CONFIDENCE AMONG GUIDANCE (ECMWF/EPS NOT BITING ON WINDS TO
THIS MAGNITUDE AND LOW (0-15%) NBM PROBS), LIMITED DURATION,
AND ONLY A MARGINAL/CONDITIONAL SET-UP LEAVE MUCH TO BE DESIRED
WHEN LOOKING TO POTENTIALLY ISSUE ANY WIND RELATED HIGHLIGHTS.
SHIFTING INLAND, PROBABILITIES FOR MAXIMUM GUSTS TO EXCEED 40MPH
ARE ONLY AROUND A 5-20% CHANCE, HIGHEST IN THE CENTRAL
WILLAMETTE VALLEY SOUTH OF THE PORTLAND METRO AREA TO THE SALEM
AREA. SO MOST LIKELY SCENARIO IS PEAK WIND GUSTS OF 25-35 MPH
FOR INLAND LOCATIONS WITH AN ISOLATED GUST OR TWO CLOSER TO 40
MPH. HIGH CONFIDENCE WINDS DROP OFF AT THE COAST AND INLAND COME
TUESDAY EVENING BRINGING AN END TO THIS CONCERN.
A SECONDARY UPPER-LEVEL SHORTWAVE AXIS MOVES EASTWARD BEHIND
THE FRONT WEDNESDAY INTO EARLY THURSDAY WHILE WE SIT IN A
CONVECTIVE POST-FRONTAL AIRMASS. THUS SHOWERS WILL CONTINUE ON
WEDNESDAY, MOST FREQUENT OVER THE CASCADES AND COAST/COAST
RANGE, BEFORE SLOWLY TAPERING OFF WEDNESDAY NIGHT INTO EARLY
THURSDAY. WHILE ELEVATED INITIALLY, SNOW LEVELS FINALLY DROP
BELOW THE PASSES EARLY WEDNESDAY MORNING WHEN THE HEAVIEST OF
STRATIFORM PRECIPITATION HAS ENDED, SO THE SNOW FORECAST
CONTINUES TO DIMINISH OVER THE CASCADES. THE NBM PROBABILITY OF
AT LEAST 6 INCHES OF SNOW OVER THE OREGON CASCADES IS LESS THAN
5-15%, EVEN FOR THE HIGHEST ELEVATIONS. THIS INCREASES SLIGHTLY
TO 15-45% FOR THE HIGHER REACHES OF THE SW WA CASCADES. SNOW
LEVELS LOWER TO 1500-2000 FT WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING, WITH A 10% CHANCE OF SNOW LEVELS FALLING NEAR VALLEY
FLOOR - WOULD NEED TRAINING SHOWERS WITH CLEARING BEFOREHAND.
HOWEVER, PRECIPITATION PROBABILITIES ALONG WITH AMOUNTS ARE SO
LOW BY THIS POINT THAT EVEN IF SOME WET SNOW DOES MIX IN, IT
WOULD NOT ACCUMULATE OR LEAD TO ANY IMPACTS, ESPECIALLY AS ROAD
SURFACES WOULD BE TOO WARM.
BY THURSDAY AFTERNOON, THE SHORTWAVE MOVES EAST OF THE AREA
WITH UPPER LEVEL FLOW BECOMING MORE ZONAL BEHIND IT. GENERALLY
ZONAL FLOW WITH SLIGHT RIDGING CONTINUES FRIDAY INTO SATURDAY,
BRINGING DRY CONDITIONS WITH CLEARING SKIES. EXPECT A WARMING
TREND WITH DAYTIME TEMPERATURES IN THE MID TO UPPER 50S ON
THURSDAY, THE LOW TO MID 60S FOR FRIDAY, AND UPPER 60S/NEAR 70
ON SATURDAY/SUNDAY FOR THE INTERIOR LOWLANDS. DURING THE PEAK OF
THE WARMING TREND (LATTER TWO DAYS) THE NBM INDICATES A 30-50%
CHANCE FOR HIGH TEMPERATURES TO MEET OR EXCEED 70 DEGREES
ACROSS THE PORTLAND METRO AREA AND WILLAMETTE VALLEY WITH
SLIGHTLY HIGHER PROBABILITIES (50-65%) SOUTH OF SALEM NEAR
EUGENE.
BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE INDICATE A DEEP
PACIFIC TROUGH MOVING EAST THROUGH THE PACIFIC AND APPROACHING
THE WEST COAST LATER ON SUNDAY INTO MONDAY, BRINGING INCREASING
CHANCES OF PRECIPITATION. HOWEVER, THIS FAR OUT, THERE IS QUITE
A BIT OF UNCERTAINTY IN REGARDS THE SPEED/AMPLITUDE OF THE
INCOMING FEATURE WITH THE LATEST MEAN ENSEMBLE GUIDANCE DELAYING
THE ARRIVAL OF THE TROUGH ANOTHER ~6HRS COMPARED TO PRIOR RUNS.
STILL, THIS UNCERTAINTY HAS LEAD TO A LARGE NBM 25TH-75TH
PERCENTILE TEMPERATURE SPREAD, SHOWING HIGHS FROM THE LOW 60S
TO THE MID 70S ARE ALL IN PLAY FOR THE WILLAMETTE
VALLEY/PORTLAND METRO SUNDAY AFTERNOON. SHOULD ENSEMBLE
GUIDANCE TREND EVEN SLOWER WITH THE AFOREMENTIONED TROUGH,
SUNDAY MAY END UP BEING THE WARMEST DAY OF THE UPCOMING LATE
WEEK/WEEKEND TIME PERIOD. WEE'LL HAVE TO SEE HOW FORECAST
SOLUTIONS CONVERGE IN THE COMING DAYS. -99/03
AVIATION
WEST TO SOUTHWEST FLOW ALOFT WITH INCREASING MOISTURE
WILL BRING MID TO HIGH LEVEL CLOUDS STREAMING ACROSS THE AREA
TODAY THROUGH TONIGHT. VFR CONDITIONS EXPECTED THROUGH AT LEAST
15Z TUESDAY, WITH CONDITIONS LIKELY REMAINING VFR INLAND THROUGH
TUESDAY MORNING. DRY CONDITIONS PREVAIL THROUGH TONIGHT WITH
GENERALLY LIGHT AND VARIABLE WINDS. A FRONTAL SYSTEM WILL APPROACH
THE COAST EARLY TUESDAY MORNING BRINGING LIGHT RAIN AND INCREASING
SOUTHERLY WINDS BY 12Z TUE. CHANCES FOR MVFR DEVELOPING AT THE
COAST INCREASES TO AROUND 30-50% AFTER 15Z TUE. WIDESPREAD RAIN
LIKELY PUSHES INLAND BY 14-16Z, BUT CHANCES FOR CONDITIONS FALLING
TO MVFR IS LESS THAN 10% ACROSS INLAND TERMINALS, UNTIL AFTER 21Z
TUE. SOUTHERLY WINDS ARE EXPECTED TO GUST UP TO 35 KT ALONG THE
COAST, PEAKING LATE TUE MORNING INTO TUE AFTERNOON. THERE IS ALSO
POTENTIAL FOR LLWS TO OCCUR INLAND WITH SSW WINDS OF AROUND 40 KT
AT 2000 FT AROUND THE SAME TIME THE RAIN BEGINS.
KPDX AND APPROACHES...VFR EXPECTED THROUGH AT LEAST 18Z TUESDAY
WITH MID TO HIGH LEVEL CLOUDS INCREASING THROUGH TONIGHT. LIGHT
WINDS BECOME SOUTHEASTERLY BY 06Z TUESDAY. LIGHT RAIN WILL BRING
LOWERING CIGS BY 15Z TUE, BUT CONDITIONS EXPECTED TO REMAIN VFR.
LLWS POSSIBLE AFTER 15Z TUE AS WELL AS SSW WINDS INCREASE AT
AROUND 2000 FT. /DH
MARINE
HIGH PRESSURE WEAKENS OVER THE COASTAL WATERS TODAY
ALLOWING NORTHERLY WINDS AROUND 10-15 KT TO FURTHER DECREASE
THROUGH THIS EVENING, WHILE SEAS GRADUALLY SUBSIDE TO AROUND 6 TO
7 FT TONIGHT. WINDS TURN SOUTHERLY OVERNIGHT AS A WARM FRONT
LIFTS NORTH ACROSS THE WATERS. THE STRENGTHENING SURFACE LOW WILL
REMAIN OFFSHORE AS IT QUICKLY MOVES NE TOWARD VANCOUVER ISLAND,
BUT SOUTHERLY WINDS ARE EXPECTED TO INCREASE ACROSS THE COASTAL
WATERS THROUGH TUESDAY MORNING AS THE ASSOCIATED GALE FORCE FRONT
APPROACHES. WIDESPREAD GUSTS OF 34 KT OR GREATER ARE EXPECTED
ACROSS ALL WATERS, WITH A 30-50% CHANCE OF PEAK GUSTS REACHING 45
KT. HAVE ISSUED A GALE WARNING FOR ALL COASTAL WATERS, INCLUDING
THE COLUMBIA RIVER BAR, FROM TUESDAY MORNING THROUGH TUESDAY
AFTERNOON.
SEAS ARE ALSO EXPECTED TO BUILD ON TUESDAY IN RESPONSE TO THE
INCREASING WIND WAVES FOLLOWED BY A WESTERLY SWELL BEHIND THE
FRONTAL PASSAGE. COMBINED SEAS WILL LIKELY BUILD TO AT LEAST 13
TO 15 FT, PEAKING BY LATE TUE AFTERNOON INTO TUE EVENING. CHANCES
FOR SEAS EXCEEDING 18 FT REMAIN LOW (5% OR LESS). BREEZY SOUTHWEST
TO WESTERLY ONSHORE WINDS WILL CONTINUE BEHIND THE FRONTAL PASSAGE
THROUGH WEDNESDAY, WHILE SEAS ARE EXPECTED TO GRADUALLY SUBSIDE TO
AROUND 9 TO 12 FT ON WEDNESDAY. HIGH PRESSURE THEN REBUILDS OVER
THE WATERS LATER THIS WEEK RETURNING NORTHERLY WINDS LATER
THURSDAY INTO FRIDAY. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...GALE WARNING FROM 6 AM TO 5 PM PDT TUESDAY FOR PZZ210-251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page