539
FXUS66 KPQR 250440
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
940 PM PDT THU APR 24 2025
UPDATED AVIATION DISCUSSION
SYNOPSIS
HIGH PRESSURE WILL MAINTAIN WARM TEMPERATURES AND
DRY WEATHER THROUGH THE REST OF THE DAY (THURSDAY). AN
APPROACHING SYSTEM WILL BRING A 15 TO 20 PERCENT CHANCE OF
THUNDERSTORMS THIS EVENING ACROSS LANE COUNTY. LINGERING SHOWERS
OVER THE CENTRAL OREGON CASCADES THROUGH SATURDAY, WITH WARM
AND DRY CONDITIONS PERSISTING ACROSS THE REST OF THE AREA. DRY,
COOLER WEATHER EXPECTED FOR SUNDAY AND MONDAY. PRECIPITATION
CHANCES RETURN TUESDAY.
SHORT TERM...NOW THROUGH SATURDAY NIGHT
THE UPPER LEVEL
RIDGE THAT BROUGHT US DRY WEATHER WITH CLEAR SKIES THE LAST
COUPLE DAYS IS NOW BEING PUSHED EASTWARD BY AN INCOMING UPPER
LEVEL TROUGH. THIS TROUGH HAS A SLIGHT NEGATIVE TILT TO IT,
TURNING FLOW ALOFT MORE SOUTHEASTERLY. ISOLATED THUNDERSTORMS
THAT MAY POP UP IN SOUTHWEST OREGON COULD BE PUSHED
NORTHWESTWARD DUE TO THE SOUTHEAST STEERING FLOW. THEREFORE, A
SLIGHT CHANCE (15-20%) FOR THUNDERSTORMS WAS INCLUDED IN THE
FORECAST ACROSS LANE COUNTY THIS EVENING FROM THE CASCADES TO
THE COAST. EXPECT ANY THUNDERSTORMS THAT DO DEVELOP TO REMAIN
WELL BELOW SEVERE THRESHOLDS GIVEN LACK OF VERTICAL WIND SHEAR.
MAIN IMPACTS FROM PASSING THUNDERSTORMS INCLUDE LIGHTNING, SMALL
HAIL, AND GUSTY AND ERRATIC WINDS.
WARM AND MOSTLY DRY CONDITIONS PERSIST ACROSS THE AREA FRIDAY
AND SATURDAY AS THE UPPER TROUGH EVOLVES INTO A CLOSED LOW AND
DROPS SOUTH TOWARD CENTRAL CALIFORNIA. WRAP AROUND MOISTURE ON
THE NORTHERN PERIPHERY OF THIS LOW WILL MAINTAIN A CHANCE OF
SHOWERS ACROSS THE SOUTHERN EXTENT OF THE AREA INTO THE WEEKEND,
WITH THE BEST PRECIPITATION CHANCES CONFINED TO THE LINN AND
LANE COUNTY CASCADES THROUGH SATURDAY. WILL NEED TO CONTINUE
TO MONITOR THUNDER POTENTIAL OVER THE NEXT FEW DAYS, BUT CHANCES
GENERALLY REMAIN BELOW 15% FOR FRIDAY AND SATURDAY AS INCREASING
CLOUD COVER HELPS TO LIMIT INSTABILITY. CAN'T RULE OUT SOME
CONVECTIVE DEBRIS (REMNANTS OF THUNDERSTORMS) MOVING INTO THE
AREA FROM NORTHERN CALIFORNIA AND SOUTHERN OREGON.
MEANWHILE, EXPECT AREAS WEST OF THE CASCADES TO GENERALLY
REMAIN DRY THROUGH THE WEEKEND AS THE LOW DROPS FARTHER SOUTH.
THE INCREASED CLOUD COVER AND SHOWER POTENTIAL OVER LANE COUNTY
WILL ALSO CONTRIBUTE TO A FAIRLY SIZABLE TEMPERATURE GRADIENT
FROM SOUTH TO NORTH, WITH THE EUGENE AREA LIKELY TO BE IN THE
LOW TO MID 60S FROM FRIDAY TO SATURDAY WHILE THE PORTLAND AREA
REMAINS IN THE MID TO UPPER 70S. -ALVIZ/CB
LONG TERM...SUNDAY THROUGH WEDNESDAY
TEMPERATURES WILL DROP
OFF MORE SUBSTANTIALLY SUNDAY AND MONDAY AS THE UPPER LOW MOVES
INTO THE GREAT BASIN AND USHERS IN BROAD ONSHORE FLOW ACROSS
THE PACIFIC NORTHWEST. THIS WILL BRING DAYTIME HIGHS CLOSER TO
SEASONAL NORMS IN THE LOW TO MID 60S THROUGH THE EARLY PART OF
NEXT WEEK. HIGH PRESSURE WILL RE-BUILD ACROSS THE AREA,
RETURNING PREDOMINATELY DRY CONDITIONS ON SUNDAY.
A PASSING SHORTWAVE TROUGH MAY BRING A FEW SHOWERS TO TO THE
AREA ON TUESDAY, BUT DO NOT SEE ANY INDICATIONS OF MEANINGFUL
PRECIPITATION AT THIS TIME. BEYOND TUESDAY, THE MAJORITY OF WPC
ENSEMBLE CLUSTERS FAVOR A RETURN OF UPPER LEVEL RIDGING OVER
THE REGION MID TO LATE NEXT WEEK, RESULTING IN ANOTHER WARMING
TREND AS DAYTIME HIGHS POTENTIALLY CLIMB BACK UP INTO THE 70S
FOR THE LATTER HALF OF NEXT WEEK. -ALVIZ/CB
AVIATION
PREVAILING VFR FLYING CONDITIONS CONTINUE INLAND
WHILE MVFR CONDITIONS ALONG THE COAST WILL TREND TO IFR
OVERNIGHT. SCT-BKN MID TO HIGH CLOUDS INLAND WITH UNRESTRICTED
VIS WILL SEE CONTINUED VFR CIG/VIS THROUGHOUT THE PERIOD ALONG
THE WILLAMETTE VALLEY. AS A COASTAL LOW TRACKS INLAND OVER
NORTHERN CA, ISOLATED TO SCATTERED LIGHT RAIN SHOWERS WILL TRACK
TO THE WEST-NORTHWEST ACROSS SOUTHERN AREAS, INCLUDING NEAR
EUG/ONP, WITH LOW LIKELIHOOD OF BRIEF IMPACTS. ELSEWHERE, DRY
CONDITIONS ARE EXPECTED. WINDS OF LESS THAN 10 KT OUT OF THE
NORTHWEST TO SOUTHWEST WILL CONTINUE ACROSS THE REGION, ASIDE
FROM LIGHT EASTERLY FLOW AT TTD THROUGH FRIDAY MORNING.
PERSISTENT MARINE STRATUS WILL SEE MVFR CIGS LOWER TO IFR AT
ONP/AST, WITH PERIODS OF LIFR CIGS AND RESTRICTED VIS MOST
LIKELY FROM 06-09Z FRI AND 12-15Z FRI AT ONP, AND 10-14Z FRI AT
AST. CONDITIONS WILL IMPROVE TO VFR/MVFR AFTER 16-18Z FRI,
ALTHOUGH SCT-BKN LOW STRATUS WILL LINGER AT 1-3 KFT. WINDS WILL
PERSISTE AT 5-10 KT OUT OF THE WEST TO NORTHWEST.
PDX AND APPROACHES...VFR CONDITIONS WILL PREVAIL THROUGHOUT THE
PERIOD. COVERAGE OF MID TO HIGH CLOUDS AT 15-25 KFT WILL INCREASE
THROUGH 09Z FRI AS A SURFACE LOW MOVES INLAND WELL TO THE SOUTH,
BEFORE SKIES TREND CLEARER AFTER 18-21Z FRI. LIGHT AND VARIABLE
WINDS THROUGH MUCH OF TONIGHT WILL TURN OUT OF THE NORTHWEST AT
AROUND 5 KT BY 18-21Z FRI. -PICARD
MARINE
STRONG HIGH PRESSURE OFFSHORE WILL MAINTAIN NORTHERLY
TO NORTHWESTERLY WINDS ACROSS THE COASTAL WATERS THROUGH THE
UPCOMING WEEKEND. NORTH TO NORTHWESTERLY WINDS WILL BEGIN TO
INCREASE FRIDAY NIGHT, WITH GUSTS UP TO 25 KT AND THESE WINDS
WILL SLOWLY SPREAD SOUTHWARD ACROSS ALL WATERS THROUGH FRIDAY
NIGHT. AT THE SAME TIME, A BUILDING WESTERLY SWELL WILL RESULT
IN SEAS BUILDING TOWARDS 7 TO 11 FT. AS A RESULT HAVE ADJUSTED
AND ADDED SMALL CRAFT ADVISORIES FOR ALL WATERS AND THESE
CONDITIONS ARE EXPECTED TO PERSIST THROUGH AT LEAST SATURDAY
EVENING. AFTERWARDS, WINDS AND SEA WILL SLOWLY SUBSIDE TO BELOW
SMALL CRAFT CONDITIONS BY THE START OF NEXT WEEK. /42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 2 AM TO 5 PM PDT SATURDAY FOR
PZZ251>253.
SMALL CRAFT ADVISORY FROM 5 PM FRIDAY TO 5 PM PDT SATURDAY FOR
PZZ271>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