619
FXUS66 KPQR 070539
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1039 PM PDT SAT JUN 6 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS
SATURDAY AFTERNOON WILL QUICKLY DISSIPATE FROM WEST TO EAST
SATURDAY EVENING. WEAK HIGH PRESSURE WILL BRING MAINLY DRY
CONDITIONS SATURDAY NIGHT THROUGH AT LEAST SUNDAY AFTERNOON.
SCATTERED LIGHT SHOWERS RETURN LATE SUNDAY EVENING/NIGHT BEFORE
WIDESPREAD STEADY RAIN ARRIVES ON MONDAY (85-95% CHANCE). STEADY
RAIN WILL THEN TRANSITION TO OFF-AND-ON SHOWERS MONDAY EVENING
AND CONTINUE THROUGH WEDNESDAY, MAINTAINING COOLER THAN AVERAGE
TEMPERATURES. TRENDING MUCH WARMER AND DRIER JUNE 11-15 WITH
INCREASING HEAT CONCERNS NEXT WEEKEND, ESPECIALLY FOR INLAND
VALLEYS.
DISCUSSION...SATURDAY AFTERNOON THROUGH FRIDAY NIGHT
RADAR,
SATELLITE, AND SURFACE WEATHER OBSERVATIONS FROM SATURDAY AFTERNOON
SHOWED NUMEROUS HEAVY SHOWERS AND ISOLATED THUNDERSTORMS OVER
SOUTHWEST WA AND NORTHWEST OR. THE STRONGEST SHOWERS AND STORMS ARE
PRODUCING BRIEF HEAVY DOWNPOURS, SMALL HAIL UP TO THE SIZE OF PEAS,
AND GUSTY OUTFLOW WINDS UP TO AROUND 30-35 MPH. CLOUD TO GROUND
LIGHTNING WILL ALSO POSE A SAFETY HAZARD FOR ANY THUNDERSTORM THAT
DEVELOPS. AREAS THAT HAVE OBSERVED REPEATED HEAVIER SHOWERS OR STORMS
HAVE PICKED UP ANOTHER FROM 0.2-0.9 INCHES OF RAIN OVER THE PAST 6-12
HOURS. DESPITE THE HEAVY RAIN RATES WITH THE STRONGEST CELLS, THESE
SHOWERS AND STORMS ARE MOVING TOO FAST TO WARRANT A THREAT OF
FLOODING AS HEAVIER BURSTS OF RAIN ARE TYPICALLY ONLY LASTING
ANYWHERE FROM 5-15 MINUTES. HOWEVER, PONDING OF WATER ON ROADS AND
REDUCED VISIBILITIES DURING HEAVIER SHOWERS WILL BE HAZARDOUS TO
MOTORISTS. THE LATEST SUITE OF CAM GUIDANCE REMAINS IN AGREEMENT FOR
AN ABRUPT END TO THE ONGOING CONVECTION AFTER 6 PM WEST OF THE
CASCADE FOOTHILLS AND AFTER 10 PM FOR THE CASCADES AND CASCADE
FOOTHILLS. THIS TIMING SEEMS REASONABLE GIVEN HIGH PRESSURE WILL BE
BUILDING INTO THE AREA THIS EVENING WHILE PEAK DAYTIME HEATING WANES.
WEAK HIGH PRESSURE WILL THEN REMAIN IN PLACE TONIGHT THROUGH AT LEAST
SUNDAY AFTERNOON, BRINGING A BRIEF BREAK FROM PRECIPITATION. HOWEVER,
CLOUD COVER WILL BE ON THE INCREASE AHEAD OF THE NEXT WEATHER SYSTEM,
RESULTING IN THE CONTINUATION OF BELOW AVERAGE HIGH TEMPERATURES IN
THE 60S. MODEL ENSEMBLE GUIDANCE HAS COME INTO BETTER AGREEMENT ON
THE ARRIVAL TIME OF RAIN WITH THE AFOREMENTIONED WEATHER SYSTEM. IT
NOW APPEARS A STEADY STRATIFORM RAIN WILL ARRIVE MONDAY MORNING INTO
THE EARLY AFTERNOON (85-95% CHANCE) BEFORE TRANSITIONING TO
OFF-AND-ON POST-FRONTAL SHOWERS MONDAY EVENING. WE WILL THEN REMAIN
IN A COOL AND SHOWERY ONSHORE FLOW REGIME THROUGH WEDNESDAY. THERE IS
ALSO A 10-20% CHANCE OF SHORT-LIVED THUNDERSTORMS TUESDAY AFTERNOON,
HOWEVER THESE WOULD BE SUB-SEVERE AND ISOLATED DUE TO LIMITED
INSTABILITY. THE LATEST NBM 48-HR PROBABILITIES FOR RAIN AMOUNTS OVER
0.50" NOW PEAKS BETWEEN 5 AM PDT MONDAY AND 5 AM PDT WEDNESDAY,
SHOWING ANYWHERE FROM A 60-80% CHANCE FOR MOST LOCATIONS IN SOUTHWEST
WA AND NORTHWEST OR, EXCEPT AN 80-95% CHANCE IN THE CASCADES, CASCADE
FOOTHILLS, AND COAST RANGE.
CONDITIONS SHOULD DRY OUT WITH TEMPERATURES TRENDING TOWARDS SEASONAL
NORMALS ON THURSDAY AS HIGH PRESSURE BUILDS INTO THE AREA. OUR FOCUS
THEN SHIFTS TO A SIGNIFICANT WARMING AND DRYING TREND LATE NEXT WEEK
THROUGH NEXT WEEKEND. 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. HOWEVER, THERE IS STILL
CONSIDERABLE UNCERTAINTY IN REGARDS TO EXACTLY HOW WARM TEMPERATURES
WILL GET, WHICH COULD WIND UP ANYWHERE IN THE 80S, 90S, OR EVEN LOWER
100S FOR INLAND VALLEYS. THAT SAID, CONFIDENCE HAS INCREASED FOR HIGH
TEMPERATURES OF AT LEAST 90 DEGREES OR WARMER BY JUNE 13-15. BY JUNE
15, PROBABILITIES FOR HIGHS ABOVE 90 DEGREES PEAK NEAR 55-75% FOR
INLAND VALLEYS PER THE LATEST NBM GUIDANCE, AND LESS THAN 10% AT THE
COAST. WITH THE INCREASE IN TEMPERATURES, THERE IS A 25-45% CHANCE
FOR A MODERATE HEATRISK OR HIGHER OVER INLAND VALLEYS ON JUNE 12, A
50-75% CHANCE ON JUNE 13, A 65-85% CHANCE ON JUNE 14, AND A 70-90%
CHANCE ON JUNE 15. THERE IS A 5-20% CHANCE FOR A MAJOR HEATRISK OR
HIGHER ON JUNE 13, A 15-35% CHANCE ON JUNE 14, AND A 20-40% CHANCE ON
JUNE 15. THOSE WHO PLAN ON SWIMMING IN LAKES OR RIVERS TO COOL DOWN
SHOULD BE MINDFUL OF THE DANGERS THAT COME WITH COLD WATER
TEMPERATURES AND/OR SWIFT CURRENTS. ANYONE WHO IS SENSITIVE TO HEAT
AND/OR HAS OUTDOOR PLANS JUNE 12-15 SHOULD PAY ATTENTION TO THE
FORECAST OVER THE COMING DAYS. -23
AVIATION
PREDOMINATELY VFR CONDITIONS THROUGH SUNDAY EVENING,
ALTHOUGH A WET GROUND SURFACE ALONG WITH CLEARING SKIES AND LIGHT
WINDS WILL RESULT IN A 25-45% CHANCE OF MVFR CLOUDS ACROSS THE
INTERIOR LOWLANDS OR FOG DEVELOPMENT IN SHELTERED LOCALES AT SOME
POINT BETWEEN 10-16Z SUN. ANY LOWERED FLIGHT CONDITIONS SHOULD
IMPROVE TO VFR BY 18-21Z SUN. WEST WINDS DECREASING LESS THAN 6
KTS WITH MOST LOCATIONS BECOMING SOUTHERLY OR VARIABLE OVERNIGHT
AS HIGH PRESSURE BUILDS OVER THE REGION, REMAINING SO THROUGH
SUNDAY.
KPDX AND APPROACHES...VFR CONDITIONS MOST LIKELY TO PREVAIL
THROUGH THE PERIOD, THOUGH THERE'S A 25-35% CHANCE OF MVFR
CEILINGS DEVELOPING SOMETIME BETWEEN 10-18Z SUN DUE TO THE WET
GROUND, CLEARING SKIES, AND LIGHT WINDS. ANY LOWERED FLIGHT
CONDITIONS SHOULD IMPROVE TO VFR BY 18-21Z SUN. WESTERLY WINDS
LESS THAN 5 KTS BECOMING VARIABLE OVERNIGHT. -03
MARINE
AN ACTIVE WEATHER PATTERN CONTINUES THROUGH MIDWEEK
WITH REPEATED FRONTAL SYSTEMS BRINGING PERIODS OF RAIN AND
INCREASED WINDS. ISOLATED RAIN SHOWERS THIS AFTERNOON WILL
RAPIDLY DECREASE IN COVERAGE IN THE HOURS BEFORE SUNSET WHILE
WEST-NORTHWEST WINDS OF 10-15 KT EASE TO AROUND 5 KT AND TURN
OUT OF THE SOUTH TONIGHT. A BRIEF DRY BREAK FROM SUNDAY INTO
MONDAY AS A SHORTWAVE RIDGE PASSES OVERHEAD WILL SEE SOUTHERLY
WINDS BUILD TO 15-20 KT WITH GUSTS UP TO 25 KT, PEAKING EARLY
MONDAY MORNING. SMALL CRAFT ADVISORIES MAY BE NEEDED IF
CONFIDENCE INCREASES IN THE DURATION OF WIND GUSTS GREATER THAN
21 KT. SEAS OF 4-8 FT AT 8-9 SECONDS CONTINUES WITH A DOMINANT
WESTERLY SWELL. THIS NEXT, MORE ROBUST FRONTAL SYSTEM WILL
ARRIVE MONDAY NIGHT INTO TUESDAY WITH ADDITIONAL RAIN AND WINDS
AGAIN TURNING WEST-NORTHWESTERLY BEHIND THE BOUNDARY.
BEYOND MIDWEEK, THERE IS HIGH CONFIDENCE THAT HIGH PRESSURE WILL
BUILD OFFSHORE, TURNING WINDS NORTHERLY OVER THE COASTAL WATERS.
DIURNAL WINDS WILL PEAK IN THE AFTERNOON AND EVENING, REACHING
15-25 KT WITH WIND GUSTS NEAR 30 KT. SEAS OF 6-8 FT AT 10 SECONDS
WITH A DOMINANT WESTERLY SWELL LOOK TO CONTINUE. -36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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