341
FXUS66 KPQR 150457 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
958 PM PDT TUE JUL 14 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
A BIT MORE OF A DYNAMIC WEATHER PATTERN OVER THE
NEXT SEVERAL DAYS AS HIGH PRESSURE GIVES WAY TO A LONGWAVE
TROUGH OVER THE AREA. RAIN CHANCES INCREASE FOR WEDNESDAY NIGHT
INTO THURSDAY WITH A SLIGHT CHANCE (10-20%) FOR THUNDERSTORMS
INTO THURSDAY MORNING. RAIN ACCUMULATION WILL GENERALLY BE
OROGRAPHICALLY DRIVEN. DRYING OCCURS STARTING FRIDAY THROUGH THE
WEEKEND AS TEMPERATURES HEAT UP ONCE AGAIN. MODERATE HEATRISK
FORECAST FOR URBAN AREAS ON SUNDAY AND MONDAY.
SHORT TERM...NOW THROUGH THURSDAY NIGHT
HIGH PRESSURE REMAINS
OVER THE AREA THROUGH WEDNESDAY MORNING WHICH IS KEEPING
CONDITIONS GENERALLY CLEAR, DRY AND WARM. SOME BLEED OVER
MONSOONAL MOISTURE LINGERS TO THE EAST OF THE CASCADES WHICH MAY
SPILL OVER THE CASCADE CREST THIS AFTERNOON IF THERE IS ENOUGH
LIFT AND WIND SHEAR ALOFT. HOWEVER, BASED ON THE CURRENT SET UP,
CHANCES FOR THUNDER TODAY IS LESS THAN 5%. THAT TREND WILL NOT
HOLD THOUGH AS WE MOVE INTO WEDNESDAY AS A BROAD CLOSED LOW
ALOFT DROPS DOWN FROM THE GULF OF ALASKA. THIS LOW IS WRAPPED IN
RELATIVELY COOLER AIR (THOUGH NOT COLD BY ANY MEANS), AND WILL
BEGIN TO INITIATE INSTABILITY. THIS LOW IS FAIRLY WELL REALIZED
IN ENSEMBLE MODELS BUT AT THE SURFACE THERE IS LESS SUPPORT.
HOWEVER, THAT DOES NOT TOTALLY ELIMINATE THE INSTABILITY IN THE
REGION.
ON WEDNESDAY NIGHT INTO THURSDAY, WE WILL SEE AN ADDITION OF
MOISTURE TO THE REGION WITH A WEAK FRONTAL BAND MOVING OVER THE
PACIFIC NORTHWEST. THE UPPER LEVEL LOW WILL SIT RIGHT OVER THE
OREGON COAST WHICH WILL BRING IN WRAP AROUND MOISTURE FROM EAST
OF THE CASCADES. WE ARE LOOKING FOR WIDESPREAD RAIN WITH WITH
AROUND A 40-50% CHANCE OF MEASURABLE RAIN WEST OF THE CASCADE
FOOTHILLS, AND A 75% CHANCE OVER THE CASCADES. THESE CHANCES
INCREASE INTO THURSDAY AFTERNOON WHERE THEY RISE TO AROUND
75-80% CHANCE OF 0.01 INCH FROM SALEM NORTHWARD. IN ADDITION TO
THE SHOWERS, CAPE WILL BE HEAVILY INCREASED OVER THE CASCADES,
AND WITH SLIGHTLY COOLER AIR ALOFT AND THE ADDED MOISTURE, WE
CANNOT RULE OUT THUNDERSTORMS OVER THE CASCADES. THESE STORMS
ARE LOOKING TO BE ON THE WETTER SIDE WITH PRECIPITABLE WATER
AROUND 90% OF NORMAL.
THERE CONTINUES TO BE A LARGE MODEL SPREAD FOR PRECIPITATION
AMOUNTS OVERALL THOUGH WITH A DIFFERENCE IN THE 25TH-75TH
PERCENTILE (MOST LIKELY RANGE) HAVING A SPREAD OF 0.3-0.5 INCH
ALONG THE COAST AND 0.25-0.40 INCH INLAND FOR 24-HR QPF ENDING
THURSDAY AFTERNOON AND EVENING. -27
LONG TERM...FRIDAY THROUGH TUESDAY
CONDITIONS WILL BEGIN TO
SETTLE ON FRIDAY, THOUGH EXPECT TEMPERATURES TO REMAIN
SEASONABLE OR JUST SLIGHTLY ABOVE NORMAL. ONCE CHALLENGE ON
FRIDAY IS WHAT ENDS UP HAPPENING WITH THE LOW ALOFT. SOME
MODELS SUGGEST THAT THE LOW WILL STAY MORE NORTHERLY, WHILE
OTHERS WANT TO KEEP IT FURTHER SOUTH. THE OVERALL GRAND ENSEMBLE
SHOWS THE LOW CENTER TRACKING P AND OVER VANCOUVER ISLAND ON
FRIDAY WHICH WILL ALLOW FOR DRIER AND WARMER AIR TO MOVE IN.
THIS WILL SET THE STAGE FOR THE WEEKEND AS CONDITIONS BECOME
INCREASINGLY HOTTER AND DRIER. IN THIS PATTERN, MARINE STRATUS
IS LIKELY, ESPECIALLY ALONG THE COAST THOUGH IT COULD TRANSITION
DOWN THE COLUMBIA RIVER INTO THE INTERIOR LOWLANDS. IF CLOUD
COVER BECOMES PERVASIVE, IT WILL HAVE AN IMPACT ON HIGH
TEMPERATURES AND MINIMUM HUMIDITY.
AS WE MOVE INTO THE WEEKEND, HIGH PRESSURE BUILDS ONCE AGAIN
WHICH WILL CAUSE TEMPERATURES TO RISE. THIS RIDGE AMPLIFIES
THROUGH MONDAY WHICH WILL BRING EVEN WARMER TEMPERATURES.
LOOKING AT MODERATE HEATRISK FOR URBAN AREAS AROUND THE GREATER
PORTLAND-VANCOUVER METRO AREA, THE COLUMBIA RIVER GORGE, AND THE
UPPER HOOD RIVER VALLEY ON BOTH SUNDAY AND MONDAY. THERE IS
AROUND A 10% CHANCE OF HIGHS HITTING 100 DEGREES OR MORE ON BOTH
MONDAY AND TUESDAY AND THAT IS MAINLY WITHIN THE INLAND VALLEYS. NOTE
THAT ONE TREND THAT HAS BEEN OBSERVED IS THAT THE HIGHEST
TEMPERATURE FORECASTS HAVE BEEN PUSHED OFF ONE DAY AT A TIME AS
MODELS COME IN. THEREFORE, THE EXACT DATES MAY BE A BIT MORE UP
IN THE AIR AS WE NEAR - ESPECIALLY AS THE RIDGE REMAINS ANCHORED
IN PLACE.-27
AVIATION
SOUTHERLY FLOW ALOFT WILL CONTINUE AS AN UPPER LEVEL
LOW SPINS OFFSHORE. MID-TO HIGH LEVEL CLOUDS WILL STREAM OVER THE
FORECAST AREA TONIGHT BUT SKIES ARE EXPECTED TO BECOME MOSTLY
CLEAR AGAIN BY WEDNESDAY MORNING AS VFR CONDITIONS ARE EXPECTED
TO CONTINUE FOR ALL INLAND LOCATIONS THROUGH AT LEAST 06Z THU.
CONDITIONS ALONG THE COAST ARE EXPECTED TO DETERIORATE AS MARINE
STRATUS MOVES ONSHORE WITH AT LEAST A 60% CHANCE OF MVFR CIGS
AFTER 06Z WED. THERE IS AROUND A 50% CHANCE FOR IFR CONDITIONS TO
DEVELOP OVERNIGHT INTO WED MORNING AT BOTH KAST AND KONP THROUGH
16-18Z WED. CONDITIONS ARE LIKELY TO IMPROVE TOWARD VFR AFTER
18-19Z WED, ESPECIALLY NEAR KAST, WHILE MVFR PROBS NEAR KONP
PERSIST AT AROUND 40-50% THROUGH WED AFTERNOON.
KPDX AND APPROACHES...VFR EXPECTED TO CONTINUE THROUGH THE PERIOD
WITH VARIABLE MID TO HIGH LEVEL CLOUDS TONIGHT BECOMING MOSTLY
CLEAR BY WED MORNING. NORTHWEST WINDS BECOME LIGHT OVERNIGHT. /DH
MARINE
BENIGN CONDITIONS WITH A TYPICAL SUMMERTIME PATTERN
EXPECTED TO PERSIST THROUGH THE WEEK. NORTHERLY WINDS 10-15 KT
EXPECTED WITH INTERMITTENT AFTERNOON GUSTS UP TO 20 KT EACH DAY.
SEAS 4-6 FEET AT 8-10 SECONDS.
A SMALL CRAFT ADVISORY IS IN EFFECT FROM 3AM TO 9AM WEDNESDAY
MORNING FOR THE COLUMBIA RIVER BAR FOR ROUGH SEAS DUE TO A VERY
STRONG EBB CURRENT LEADING TO SEAS OF 6 TO 7 FT. /42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 AM TO 9 AM PDT WEDNESDAY FOR PZZ210.
WWW.WEATHER.GOV/PORTLAND
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