391
FXUS66 KPQR 011110
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
410 AM PDT TUE APR 1 2025
SYNOPSIS
SCATTERED SHOWERS TODAY BECOME MORE WIDESPREAD ON
WEDNESDAY AS UPPER LEVEL TROUGHING REMAINS OVER THE REGION, WITH
HIGH TEMPERATURES IN THE 50S. CHILLY OVERNIGHT LOWS BRING FROST
POTENTIAL THURSDAY AND FRIDAY MORNING. EXPECT WARMER AND DRIER
CONDITIONS WITH HIGHS NEAR OR ABOVE 70 DEGREES FRIDAY INTO THE
WEEKEND.
SHORT TERM...NOW THROUGH THURSDAY NIGHT
EARLY MORNING RADAR
IMAGERY SHOWS ISOLATED TO SCATTERED SHOWER ACTIVITY ONGOING
ACROSS THE AREA IN ASSOCIATION WITH AN AREA OF LOW PRESSURE
LOCATED JUST OFF THE CENTRAL OREGON COAST NEAR FLORENCE. SHOWERS
WILL INCREASINGLY BE CONCENTRATED SOUTH OF A NEWPORT-SALEM-MT
JEFFERSON LINE THIS MORNING AS THE LOW DROPS SOUTH TOWARDS THE
CALIFORNIA BORDER, RESULTING IN DRIER WEATHER WITH A FEW BREAKS
OF SUNSHINE ACROSS THE NORTHERN HALF OF THE AREA TO START THE
DAY. SHOWERS WILL FILL BACK IN ACROSS THE AREA LATER THIS
AFTERNOON AS DAYTIME HEATING HELPS TO GENERATE MODEST
INSTABILITY, BUT THUNDERSTORM POTENTIAL WILL BE MINIMAL (LESS
THAN 10%) AS MODEL SOUNDINGS CONTINUE TO INDICATE WEAK AND
SHALLOW CONVECTION WHICH WILL NOT BE CONDUCIVE TO CHARGE
SEPARATION. QPF AMOUNTS WILL BE MINIMAL, WITH SOME LOCATIONS
LIKELY TO REMAIN DRY THROUGH THE DAY GIVEN THE HIT OR MISS
NATURE OF THE SHOWER ACTIVITY. SHOWERS WILL BECOME MORE
PREVALENT AGAIN TONIGHT INTO WEDNESDAY AS ANOTHER SHORTWAVE
CROSSES THE REGION IN NORTHWEST FLOW. AGAIN DO NOT EXPECT
THUNDERSTORMS AS INSTABILITY REMAINS MEAGER, WITH PRECIPITATION
AMOUNTS LOOKING TO REMAIN BETWEEN A TENTH AND A QUARTER INCH
ALONG THE COAST AND AROUND A TENTH OR LESS INLAND. MINIMAL SNOW
ACCUMULATIONS WILL REMAIN POSSIBLE IN THE CASCADE PASSES AS SNOW
LEVELS CONTINUE TO RESIDE AROUND 2500-3000 FEET. THURSDAY STILL
LOOKS TO BE A DAY OF TRANSITION AS DRY NORTHERLY FLOW DEVELOPS
BEHIND THE DEPARTING UPPER LEVEL TROUGH. CLEARING SKIES
OVERNIGHT WILL ALLOW FOR A CHILLY START TO THE DAY WITH
TEMPERATURES DROPPING INTO THE MID OR EVEN LOW 30S ACROSS MUCH
OF THE INTERIOR LOWLANDS. AS SUCH, AND WITH THE START OF SPRING
GROWING SEASON, WILL HAVE TO CONTINUE TO MONITOR THE POTENTIAL
FOR FROST ADVISORIES WEDNESDAY NIGHT INTO THURSDAY MORNING.
OTHERWISE EXPECT A PLEASANT EARLY SPRING DAY WITH AFTERNOON
HIGHS IN THE UPPER 50S ON THURSDAY. /CB
LONG TERM...FRIDAY THROUGH MONDAY
AFTER ANOTHER CHILLY START
TO THE DAY ON FRIDAY, THE EXPECTED WARMING AND DRYING TREND
KICKS INTO HIGH GEAR AS ENSEMBLES REMAIN IN EXCELLENT AGREEMENT
ON A STOUT UPPER LEVEL RIDGE BUILDING OVER THE PACIFIC
NORTHWEST INTO THE WEEKEND. FOR THE MOST PART EXPECT INLAND HIGHS
WELL INTO THE 60S ON FRIDAY AFTERNOON, WITH THE NBM GIVING ABOUT
A 50/50 CHANCE TO REACH 70 DEGREES IN THE PORTLAND/VANCOUVER
METRO. NBM PROBS INCREASE TO 60-80 PERCENT THROUGHOUT THE
WILLAMETTE VALLEY ON SATURDAY. FORECAST CONFIDENCE HAS NOTABLY
DECREASED ON SUNDAY, DRIVEN MAINLY BY MODEL TIMING DIFFERENCES
IN THE BREAKDOWN OF THE RIDGE AND SUBSEQUENT ARRIVAL OF THE
NEXT UPPER LEVEL TROUGH. GEFS MEMBERS HAVE SHIFTED EARLIER WITH
THIS SCENARIO AND NOW INCREASE PRECIPITATION CHANCES DURING THE
DAY ON SUNDAY, WHEREAS ECENS GUIDANCE MOSTLY HOLDS OFF UNTIL
SUNDAY NIGHT OR MONDAY. AS A RESULT, NBM PROBS TO REACH 70
DEGREES HAVE FALLEN TO 50-70 PERCENT IN THE LOWLANDS ON SUNDAY,
WITH THE PROBABILITY TO REACH 80 NOW UNDER 10 PERCENT AREA
WIDE. REGARDLESS, STILL EXPECT TEMPERATURES TO REMAIN ABOVE
NORMAL THROUGH SUNDAY, WITH THE TIMING OF THE ARRIVAL OF THE
NEXT ROUND OF PRECIPITATION AS THE PRIMARY FORECAST QUESTION.
MODELS ARE IN GENERAL AGREEMENT THAT THIS WILL OCCUR BY NEXT
MONDAY AT THE LATEST AS THE RIDGE SHIFTS EAST OF THE AREA, WITH
TEMPS TRENDING BACK DOWN INTO THE LOWER 60S AS A RESULT. /CB
AVIATION
RADAR, SATELLITE, AND SURFACE OBSERVATIONS AS OF 10Z
TUESDAY SHOW A WEAK LOW PRESSURE SYSTEM MOVING INLAND INTO
SOUTHWEST OREGON. THIS LOW IS BRINGING LIGHT RAIN TO KONP/KEUG AS
WELL AS OVERCAST VFR CIGS ACROSS MOST OF NORTHWEST OREGON. DUE TO
THIS OVERCAST LAYER, IT WILL LIKELY BE DIFFICULT FOR FOG FORMATION
THIS MORNING ACROSS MOST TERMINALS. PORTLAND METRO TERMINALS
(HIO/PDX/TTD) STILL HAVE A 10-30% CHANCE FOR LIFR FOG BETWEEN
12-18Z TUE DUE TO THE MORE BROKEN NATURE OF THE CLOUD DECK IN THIS
AREA. GAPS IN CLOUD COVER MAY ALLOW FOR THE DEVELOPMENT OF
RADIATION FOG, MOST LIKELY NEAR BODIES OF WATER, INCLUDING ALONG
THE COLUMBIA RIVER ITSELF, AS WELL AS WITHIN SHELTERED VALLEYS.
OTHERWISE, WILLAMETTE VALLEY TERMINALS HAVE A 30-50% CHANCE FOR
IFR STRATUS BETWEEN 12-18Z TUE AS THE SURFACE MOISTENS THIS
MORNING. THE SOUTHERN VALLEY (KEUG) IS ALREADY EXPERIENCING MVFR
CIGS. AFTER 18-21Z TUE, EXPECT PREDOMINATELY VFR THRESHOLDS
ACROSS ALL TERMINALS AS DAYTIME HEATING PROGRESSES. NORTHERLY TO
NORTHWESTERLY WINDS REMAIN UNDER 10 KT ACROSS ALL TERMINALS TODAY.
COASTAL TERMINALS MAY SEE GUSTS UP TO 20 KT AFTER 21Z TUE.
PDX AND APPROACHES...MOSTLY VFR THROUGH THE TAF PERIOD, WITH A
10-30% CHANCE FOR LIFR FOG AND A 30-50% CHANCE OF IFR STRATUS
BETWEEN 12-18Z TUE. LOW CONFIDENCE IN FOG DUE TO BROKEN-OVERCAST
CLOUD COVER. ANY FOG OR LOW STRATUS THAT DEVELOPS THIS MORNING
SHOULD LIFT AFTER 18Z TUE AND IMPROVE TO VFR. NORTHWEST WINDS
TODAY GENERALLY AROUND 5 KT OR LESS. -ALVIZ/PICARD
MARINE
A WEAK LOW PRESSURE SYSTEM MOVING INLAND WILL CONTINUE
BREEZY EASTERLY WINDS ACROSS THE WATERS THIS (TUESDAY) MORNING.
THE STRONGEST GUSTS (UP TO 20 KT) ARE EXPECTED SOUTH OF CAPE
FOULWEATHER DUE TO THE MORE SOUTHERN POSITION OF THE LOW, WHILE
WINDS EVERYWHERE ELSE REMAIN 5-15 KT. SEAS SHOULD PEAK THIS
MORNING AROUND 9-11 FT AT 11 SECONDS AS A SOUTHWESTERLY SWELLS
PUSHES THROUGH THE WATERS. LATER THIS AFTERNOON, WINDS ARE
FORECAST TO TURN NORTHWESTERLY 10-20 KT AS HIGH PRESSURE RE-
BUILDS. SLIGHT TIGHTENING OF PRESSURE GRADIENTS COULD LEAD TO
OCCASIONAL GUSTS UP TO 25 KT, HOWEVER, IT'S NOT WIDESPREAD ENOUGH
TO WARRANT AN ISSUANCE OF A SMALL CRAFT ADVISORY FOR THIS
AFTERNOON. WEDNESDAY THROUGH THE END OF THE WEEK, HIGH PRESSURE
WILL MAINTAIN BENIGN MARINE CONDITIONS WITH WEAKENING WINDS AND
SUBSIDING SEAS. -ALVIZ
BEACH HAZARDS
MINOR COASTAL FLOODING DUE TO TIDAL OVERFLOW
IS POSSIBLE ALONG THE NORTH OREGON COAST AND SOUTH WASHINGTON
COAST EARLY THIS MORNING DUE TO A FAIRLY ROBUST HIGH TIDE IN
COMBINATION WITH LINGERING SURGE FROM THIS PAST WEATHER
DISTURBANCE. WITH A TOTAL TIDE OF ~10.5-11.3 FEET IN THIS
REGION, FLOODING UP TO ONE FOOT ABOVE GROUND LEVEL WILL BE
POSSIBLE FOR THE LOWEST LYING COASTAL AREAS LIKE ALONG PORTIONS
OF HIGHWAY 101 NEAR RAYMOND. ANY THREAT FOR TIDAL OVERFLOW ENDS
BY 6-7 AM THIS MORNING. -ALVIZ/SCHULDT
PQR WATCHES/WARNINGS/ADVISORIES
OR...COASTAL FLOOD ADVISORY UNTIL 6 AM PDT EARLY THIS MORNING FOR
ORZ101.
WA...COASTAL FLOOD ADVISORY UNTIL 6 AM PDT EARLY THIS MORNING FOR
WAZ201.
PZ...SMALL CRAFT ADVISORY UNTIL 11 AM PDT THIS MORNING FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT EARLY THIS MORNING FOR
PZZ251>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