629
FXUS66 KPQR 052103 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
202 PM PDT FRI JUN 5 2026
SYNOPSIS
A FAIRLY PROGRESSIVE UPPER-LEVEL WEATHER PATTERN AND A
SERIES OF FRONTAL SYSTEMS WITH BRING COOLER THAN AVERAGE TEMPERATURES
AND PERIODIC ROUNDS OF SHOWERS TO THE AREA THROUGH WEDNESDAY, JUNE
10. THERE IS ALSO A 15-30% CHANCE OF SHORT-LIVED THUNDERSTORMS
SATURDAY AFTERNOON AND A 10-20% CHANCE TUESDAY AFTERNOON. UPPER LEVEL
RIDGING WILL BRING A WARMING AND DRYING TREND JUNE 11-15, WITH
POTENTIAL HEAT CONCERNS JUNE 12-15.
SHORT TERM...NOW THROUGH MONDAY NIGHT
SATELLITE, RADAR, AND
SURFACE WEATHER OBSERVATIONS FROM EARLY FRIDAY AFTERNOON DEPICTED
SCATTERED LIGHT RAIN SHOWERS OCCURRING OVER SOUTHWEST WA, THE NORTH
OREGON COAST/COAST RANGE, AND THE NORTHERN WILLAMETTE VALLEY/PORTLAND
METRO. THESE SHOWERS HAVE BEEN TOO SHALLOW THUS FAR FOR MIXED-PHASED
CLOUDS TO DEVELOP (ECHO TOPS ARE GENERALLY BELOW 10 KFT), WHICH HELPS
EXPLAIN WHY LIGHTNING HAS NOT BEEN OBSERVED WITH THIS CONVECTION.
WHILE A "ONE-HIT-WONDER" LIGHTNING STRIKE CANNOT BE COMPLETELY RULED
OUT IF A CELL OVERPERFORMS LATER THIS AFTERNOON, CURRENT TRENDS
SUGGEST SHOWERS WILL STRUGGLE TO GROW DEEP ENOUGH TO SUPPORT CHARGE
SEPARATION/LIGHTNING. AS SUCH, THERE ARE NO NOTEWORTHY IMPACTS
OCCURRING WITH THESE SHOWERS.
SIMULATED REFLECTIVITY GUIDANCE FROM THE LATEST SUITE OF CAMS
SUGGESTS THESE SHOWERS WILL BECOME MORE ISOLATED THIS EVENING INTO
TONIGHT WITH THE LOSS OF DAYTIME HEATING. HOWEVER, SHOWERS WILL
BECOME MORE WIDESPREAD AND RELATIVELY HEAVIER SATURDAY MORNING AND
AFTERNOON AS DAYTIME HEATING RESUMES AND SYNOPTIC SCALE LIFT RAMPS UP
AHEAD OF AN INCOMING UPPER LEVEL TROUGH. THIS TROUGH WILL ALSO BRING
COOLER AIR ALOFT AND STEEPENING MID-LEVEL LAPSE RATES, SUPPORTING A
15-30% CHANCE OF THUNDERSTORMS OVER NORTHWEST OR AND SOUTHWEST WA
DURING THE AFTERNOON AND EARLY EVENING HOURS (MAINLY NORTH OF A LINE
EXTENDING FROM FLORENCE TO EUGENE TO OAKRIDGE). UNLIKE TODAY,
EQUILIBRIUM LEVELS WITH THE CONVECTION ON SATURDAY SHOULD BE HIGH
ENOUGH TO SUPPORT MIXED-PHASED CLOUDS CAPABLE OF CHARGE SEPARATION
WITH THE STRONGEST CELLS. AS SUCH, THE STRONGEST CELLS ON SATURDAY
WILL HAVE THE POTENTIAL TO PRODUCE BRIEF HEAVY RAIN, SMALL HAIL,
GUSTY OUTFLOW WINDS, AND A FEW FLASHES OF LIGHTNING. IT IS WORTH
NOTING THAT ANY GIVEN SHOWER OR STORM WILL BE SHORT-LIVED AND
SUB-SEVERE AS WIND SHEAR IS LIMITED AND ORGANIZED CONVECTION IS NOT
EXPECTED. THERE WILL ALSO BE BREAKS IN PRECIPITATION IN BETWEEN
SHOWERS, SO THOSE WITH OUTDOOR ACTIVITIES SHOULD NOT EXPECT AN
ALL-DAY WASHOUT. NEVERTHELESS, HAVE YOUR RAIN JACKETS HANDY AS IT IS
UNLIKELY ANY GIVEN LOCATION WILL STAY DRY THE ENTIRE DAY. AS ALWAYS,
BE SURE TO HEAD INDOORS IF YOU HEAR THUNDER AND/OR SEE A LIGHTNING
FLASH IF POSSIBLE.
IN ADDITION TO SHOWERS AND POTENTIAL THUNDERSTORMS, INCREASING
ONSHORE FLOW WILL KEEP WESTERLY WINDS BREEZY THROUGH THE CENTRAL
COLUMBIA GORGE AND UPPER HOOD RIVER VALLEY THROUGH SATURDAY WITH
GUSTS GENERALLY BETWEEN 25-35 MPH. THAT SAID, THERE IS ALSO A 5-15%
CHANCE FOR ISOLATED WIND GUSTS OF 40-45 MPH ANY GIVEN HOUR THROUGH
SATURDAY AFTERNOON FOR WEST-FACING EXPOSED RIDGETOPS IN THESE AREAS.
IF THE LOW SHIFTS ANY FURTHER NORTH, THESE WINDS WOULD END UP
RELATIVELY WEAKER.
COME SATURDAY EVENING INTO EARLY SUNDAY MORNING, DETERMINISTIC
AND ENSEMBLE MODELS REMAIN IN GOOD AGREEMENT AND SHOW THE UPPER LEVEL
TROUGH AXIS SHIFTING EASTWARD, ALLOWING FOR A WEAK TRANSITORY RIDGE
OF HIGH PRESSURE TO PASS OVERHEAD. THIS WILL BRING A BRIEF PERIOD OF
DRY WEATHER ON SUNDAY DURING AT LEAST THE MORNING AND AFTERNOON
HOURS. HOWEVER, CHANCES FOR STEADY LIGHT STRATIFORM RAIN INCREASE
LATE SUNDAY EVENING INTO MONDAY AS THE NEXT PACIFIC FRONTAL SYSTEM
APPROACHES. THERE IS STILL CONSIDERABLE MODEL DISAGREEMENT REGARDING
THE EXACT TIMING THIS SYSTEM WILL MOVE INLAND, WITH SOME GUIDANCE
SHOWING RAIN BEGINNING AS EARLY AS 5-11 PM SUNDAY AND OTHER GUIDANCE
SHOWING RAIN BEGINNING AS LATE AS 5-11 PM MONDAY. ALL MEMBERS FROM
THE ENS/GEFS/GEPS EVENTUALLY SHOW RAIN ARRIVING WITH THIS SYSTEM,
DESPITE THE TIMING DIFFERENCES. -23
LONG TERM...TUESDAY THROUGH THURSDAY NIGHT
THE LONG TERM FORECAST
STARTS OUT WITH COOLER THAN AVERAGE TEMPERATURES AND OCCASIONAL
SHOWERS, AND ENDS WITH A WARMING AND DRYING TREND. DESPITE THE MODEL
TIMING DIFFERENCES DISCUSSED ABOVE WITH THE ARRIVAL OF A FRONTAL
SYSTEM LATE SUNDAY INTO MONDAY, ENSEMBLE GUIDANCE IS IN GOOD
AGREEMENT THE AREA WILL BE SOLIDLY WITHIN A POST-FRONTAL SHOWERY
ENVIRONMENT TUESDAY THROUGH WEDNESDAY UNDER A BROAD UPPER LEVEL
TROUGH. THIS WILL MAINTAIN COOLER THAN AVERAGE TEMPERATURES AND
OCCASIONAL RAIN, WITH HIGH TEMPERATURES MOST LIKELY IN THE 60S. IT
APPEARS SHOWERS WILL BE MOST FREQUENT ON TUESDAY, WHICH IS ALSO WHEN
THE NBM SUGGESTS THERE IS A 10-20% CHANCE OF THUNDERSTORMS DURING THE
AFTERNOON. NBM 48-HR PROBABILITIES FOR RAIN AMOUNTS OVER 0.25" PEAKS
BETWEEN 5 AM MONDAY AND 5 AM WEDNESDAY, SHOWING ANYWHERE FROM A
45-75% CHANCE FOR MOST LOCATIONS IN SOUTHWEST WA AND NORTHWEST OR,
EXCEPT AN 80-90% CHANCE IN THE CASCADES.
CONDITIONS BEGIN TRENDING WARMER AND DRIER FROM THURSDAY ONWARD.
CLUSTER ANALYSIS FOR JUNE 11-15 FOR 500 MB HEIGHTS GENERALLY SUGGEST
UPPER LEVEL RIDGING WILL GRADUALLY DEVELOP OVER THE REGION. THIS WILL
BRING A PROLONGED STRETCH OF DRY WEATHER, WITH TEMPERATURES LIKELY
WARMING EACH DAY. WHILE CONFIDENCE IS HIGH TEMPERATURES WILL WARM
SIGNIFICANTLY COMPARED TO EARLY IN THE WEEK, CONFIDENCE IS LOW
REGARDING EXACTLY HOW WARM TEMPERATURES WILL GET. THE NBM 1D VIEWER
FOR HIGH/LOW TEMPERATURES REFLECTS THIS UNCERTAINTY WELL, SHOWING
LARGE MODEL SPREAD JUNE 11-15. FOR EXAMPLE, THE NBM 10TH-90TH
PERCENTILE FOR HIGH TEMPERATURES JUNE 13-15, WHICH WILL LIKELY BE THE
WARMEST DAYS, RANGES FROM THE UPPER 70S TO NEAR 100 DEGREES FOR
INLAND VALLEY AND UPPER 60S TO UPPER 80S FOR COASTAL LOCATIONS.
PROBABILITIES FOR A MODERATE HEATRISK OR HIGHER REACH 25-45% FOR
INLAND VALLEYS ON JUNE 12, 50-75% ON JUNE 13, AND 65-85% ON JUNE 14.
THERE IS A 5-20% CHANCE FOR A MAJOR HEATRISK OR HIGHER ON JUNE 13 AND
A 10-30% CHANCE ON JUNE 14. REGARDLESS OF WHAT MATERIALIZES, THOSE
PLANNING ON SWIMMING IN RIVERS OR LAKES SHOULD EXERCISE COLD WATER
SAFETY AND BE MINDFUL OF THE DANGERS THAT COME WITH COLD WATER. THOSE
WHO ARE SENSITIVE TO HEAT AND/OR HAVE OUTDOOR PLANS SHOULD KEEP AN
EYE ON THE FORECAST OVER THE NEXT WEEK. -23
AVIATION
EXPECT GENERALLY VFR CONDITIONS ACROSS THE AIRSPACE AS
A TROUGH, CURRENTLY OVER THE GULF OF ALASKA SLOWLY DRIFTS
SOUTHEASTWARD TOWARDS. CURRENT SURFACE OBSERVATIONS SHOW CLOUD
DECKS ACROSS THE AIRSPACE AROUND FL040-FL060. A SERIES OF WEAK
FRONTS, ASSOCIATED WITH THE ALASKAN LOW, WILL SLOWLY PUSH INLAND
THROUGH THE DAY. THIS WILL RESULT IN BRIEF SHOWERS IMPACTING
LOCATIONS NORTH OF KONP ALONG THE COAST AND KSLE FOR INLAND
LOCATIONS. THESE SHOWERS LOOK TO BE LIGHT WITH MINIMAL IMPACTS,
BUT CANNOT RULE OUT BRIEF PERIODS OF MVFR CONDITIONS WHICH WILL BE
ASSOCIATED WITH SAID SHOWERS THROUGH AT LEAST THE END OF THE TAF
PERIOD. SOUTHWEST TO WEST WINDS BETWEEN 5-10 KT AT MOST SITES.
THERE IS A 5-15% CHANCE FOR THUNDERSTORMS THROUGH 12Z SATURDAY
MAINLY FOR KAST AND THE PORTLAND METRO TERMINALS WITH LIMITED, IF
ANY IMPACTS.
KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS BETWEEN
FL035-FL060. LIGHT SHOWERS POSSIBLE THROUGH THE TAF PERIOD WHICH
COULD RESULT IN BRIEF PERIODS OF MVFR CONDITIONS. /42
MARINE
OVERALL FAIRLY BENIGN CONDITIONS EXPECTED THROUGH THE
WEEKEND AND INTO NEXT WEEK. EXPECT A SERIES OF WEAK FRONTAL
SYSTEMS WHICH WILL BRING INCREASING WINDS AND BUILDING SEAS.
THE FIRST OF THESE FRONTAL SYSTEMS ARRIVING TODAY ALLOW SEAS TO
BUILD INTO THE 5-8 FT RANGE AT 10-12 SECONDS WITH WESTERLY WINDS
GUSTING UP TO 20 KT. THEN A MORE ROBUST FRONT ARRIVES SATURDAY,
BRINGING MORE NORTHWESTERLY WINDS BY THE AFTERNOON. WINDS ONLY
INCREASE MARGINALLY WITH ONLY A 10-25% CHANCE FOR SMALL CRAFT
ADVISORY WIND GUSTS - HIGHEST PROBABILITIES ACROSS THE OUTER
WATERS. GIVEN THE MINIMAL CONFIDENCE IN SMALL CRAFT CONDITIONS,
HAVE DECIDED TO NOT ISSUE ANY HEADLINES AT THIS TIME. AFTER A
LULL DURING THE DAY ON SUNDAY AS HIGH PRESSURE BRIEFLY RETURNS,
WINDS INCREASE YET AGAIN ON MONDAY AS A COMPARATIVELY STRONGER
SYSTEM MOVES OVER THE WATERS, BRINGING SOUTH WIND GUSTS UP TO 25
KT AND SEAS APPROACHING 5-8 FT. CONDITIONS THEN GRADUALLY CALM
INTO THE MIDDLE THE OF THE WEEK AS A RIDGE OF HIGH PRESSURE
ATTEMPTS TO REBUILD OVERHEAD AND NORTHWESTERLY WINDS RETURN WHILE
SEAS HOLD AROUND 5-7FT AROUND 9-11 SECONDS. /42-99
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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