324
FXUS66 KPQR 101759 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1059 AM PDT FRI APR 10 2026
UPDATE
THE SPC CONVECTIVE OUTLOOK HAS BEEN UPDATED, WITH NOW A MARGINAL
RISK FOR SEVERE WEATHER FROM EUGENE TO MOLALLA. MOST AREAS
OUTSIDE OF THIS CORRIDOR REMAINS UNDER A GENERAL THUNDERSTORM
RISK. STORMS ARE MOST LIKELY BETWEEN 1 PM AND 11PM TODAY.
SYNOPSIS
WARM AND UNSETTLED WEATHER IS EXPECTED TODAY AS
BROAD SOUTHERLY FLOW KEEPS SHOWER AND THUNDERSTORM CHANCES
OVERHEAD INTO THE FIRST HALF OF THE WEEKEND, ESPECIALLY ACROSS
THE CASCADES AND ADJACENT FOOTHILLS. AT THIS POINT CHANCES FOR
SEVERE THUNDERSTORMS APPEAR LOW (5-10%) BUT ACTIVITY MAY BE
IMPACTFUL NONETHELESS. NEXT WEEK WE'LL EVENTUALLY TRANSITION
INTO MORE OF A WESTERLY TO NORTHWESTERLY FLOW PATTERN LEADING TO
THE RETURN OF COOLER TEMPERATURES, CASCADE SNOWFALL, AND
INCREASING PRECIPITATION CHANCES FOR LATE TUESDAY INTO
WEDNESDAY.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
IT TAKES A FAIRLY
SPECIFIC SET-UP FOR WESTERN OREGON AND SOUTHWESTERN WASHINGTON
TO SEE WIDESPREAD THUNDERSTORM ACTIVITY, AND FOR THOSE ACHING TO
SEE A LITTLE LIGHTNING (MUCH LIKE THIS METEOROLOGIST), TODAY
AND SATURDAY ARE SHAPING UP TO BE BEST CHANCES WE'VE SEEN SO FAR
THIS YEAR. ALTHOUGH, AS WITH MOST OF OUR THUNDERSTORM POTENTIAL
HERE IN THE PACIFIC NORTHWEST, IT'S NOT WITHOUT A POTENTIAL
PITFALL OR TWO - NUANCES IN VARIABLES LIKE SKY-COVER CAN MAKE OR
BREAK STORM DEVELOPMENT.
AS FAR THE OVERALL SET-UP IS CONCERNED, ONE OF THE MOST
IMPORTANT PIECES IS ALREADY IN PLACE EARLY THIS MORNING IN THE
FORM OF AN UPPER-LEVEL CLOSED LOW OFF THE FAR NORTHERN
CALIFORNIA COASTLINE CURRENTLY CIRCULATING MID TO HIGH CLOUDS
OVERHEAD AND INDICATIVE OF INCREASING MOISTURE ALOFT WHILE VOID
OF ANY PACIFIC MARINE INFLUENCE. AS THE DAYS GOES ON, THIS LOW
PRESSURE IS EXPECTED TO EVER SO SLOWLY DRIFT NORTHWARD AND
TRANSITION TO MORE OF AN OPEN WAVE FEATURE WHILE PLACING THE
REGION BENEATH FURTHER STRENGTHENING SOUTHERLY TO SOUTHEASTERLY
FLOW ACCOMPANIED BY BROAD UPPER-LEVEL DIVERGENCE. THESE OVER-
ARCHING SYNOPTICS COMBINED WITH INCREASING MOISTURE VALUES
(PWATS NEAR THE 90-95% PERCENTILE FOR THIS TIME OF YEAR), AND
DAYTIME HEATING SHOULD PROVIDE THE INGREDIENTS TO FACILITATE
DEEPER CONVECTION. MOST CAMS AND DETERMINISTIC MODELS DEPICT
AROUND 400-800 J/KG OF MUCAPE BY THE MID TO LATE AFTERNOON
HOURS. ASSUMING THIS AMOUNT OF CAPE IS TRULY AVAILABLE AND
ACTIVITY IS ABLE TO INITIATE (MAINLY ALONG TERRAIN FEATURES LIKE
THE CASCADES AT FIRST), EFFECTIVE SHEAR VALUES OF ~25 KNOTS
COULD ALLOW A STORM OR TWO TO ORGANIZE BEYOND YOUR BASIC POP-UP
THUNDERSTORM - AN ISOLATED AND LONGER LIVED MULTICELLULAR STORM
OR TWO ARE POSSIBLE MAINLY SOUTH OF THE PORTLAND METRO WHERE
CAPE IS MAXIMIZED. LIGHTNING, SMALL HAIL, LOCALLY GUSTY WINDS,
AND HEAVY RAIN WOULD BE THE PRIMARY IMPACTS FROM ANY
THUNDERSTORM ACTIVITY. WHILE THE OVERALL SET-UP IS DECENT FOR
WEST OF THE CASCADES CRESTS, WOULD PLACE THE CHANCE OF A SEVERE
T-STORM AT AROUND ~5% - FOR ADDITIONAL CONTEXT THE
AFOREMENTIONED CONVECTIVE PARAMETERS DON'T HOLD A CANDLE TO
COMMON SET-UPS EAST OF THE ROCKIES. WOULD BE A BIT MORE
EXCITED IF MUCAPE VALUES WERE 1000-1500+ J/KG AND EFFECTIVE
SHEAR WAS 35+ KNOTS BUT I DIGRESS.
AS FAR AS TIMING IS CONCERNED, BASED ON THE LATEST 00Z HREF AND
UW-WRF, SHOWERS AND THUNDERSTORMS WOULD MOST LIKELY BEGIN
AROUND LANE COUNTY IN THE EARLY TO MID AFTERNOON HOURS (1-3PM)
BEFORE WORKING NORTHWARD ALONG THE CASCADES AND I-5 CORRIDOR
TOWARDS THE PORTLAND METRO BY THE LATE AFTERNOON/EARLY EVENING
(5-8PM). AFTER THIS POINT DUE TO THE LOSS OF DAYTIME HEATING
WE'D LIKELY TRANSITION BACK TO JUST LINGERING SHOWERS FOR FRIDAY
NIGHT. NOW THERE IS ONE VARIABLE ALLUDED TO EARLIER WHICH WILL
PLAY A PIVOTAL ROLE AS TO WHETHER THUNDERSTORMS REMAIN MORE
ISOLATED AND PINNED TO THE CASCADES, OR IF MODEST CONVECTION IS
WIDESPREAD AND INFILTRATES WESTWARD INTO THE I-5 CORRIDOR:
CLOUD COVER. ALMOST ALL OF THE HIGH RESOLUTION GUIDANCE WHICH IS
MORE BULLISH ON THUNDERSTORM ACTIVITY (HRRR, UW-WRF, ETC.) HAS
MID TO HIGH LEVEL CLOUD COVER CLEARING BY THE LATE MORNING AND
MIDDAY HOURS ALLOWING US TO ENHANCE OUR DAYTIME HEATING, WHILE
THE 00Z NAMNEST (BEARISH REGARDING STORMS) KEEPS ADDED CLOUDS
OVERHEAD EFFECTIVELY CAPPING OUR INSTABILITY AND LIMITING
ACTIVITY. THIS'LL BE A KEY FACET OF THE FORECAST TO WATCH BOTH
TODAY AND THIS WEEKEND.
BY SATURDAY, ENSEMBLE GUIDANCE INDICATES CONTINUED BROAD
CYCLONIC FLOW OVER THE PACIFIC NORTHWEST AS THE PREVIOUS CLOSED
LOW TURNED OPEN WAVE EJECTS NORTHWARD WHILE WEAKENING AND A
SECONDARY UPPER-LEVEL LOW SWINGS JUST OFF THE COAST OF
CALIFORNIA EFFECTIVELY STALLING THE PATTERN. SHOWER CHANCES
PEAK AREA-WIDE IN THE AFTERNOON WITH THUNDERSTORM PROBABILITIES
RANGING FROM 15-35%, HIGHEST OVER THE OREGON CASCADES AND
FOOTHILLS. WHILE OVERALL INSTABILITY ON SATURDAY AFTERNOON
APPEARS A TOUCH LESS THAN THE DAY PRIOR, ONLY 300-600 J/KG OF
MUCAPE, THE STRONGEST CELLS MAY ONCE AGAIN PRODUCE LIGHTNING,
SMALL HAIL, GUSTY WINDS, AND MODERATE TO HEAVY RAIN.
CONFIDENCE IS MODERATE TO HIGH COME SUNDAY THE UPPER-LEVEL LOW
PRESSURE PREVIOUSLY OFF THE CALIFORNIA COAST MOVES INLAND
TURNING OUR FLOW MORE WESTERLY AND THUS EFFECTIVELY ENDING ANY
ADDITIONAL CHANCES FOR THUNDERSTORMS OUTSIDE OF THE LANE COUNTY
CASCADES (15% CHANCE HERE). STILL, WRAP-AROUND MOISTURE ON THE
NORTHERN PERIPHERY OF THE BROADER CIRCULATION WILL MAINTAIN
SHOWERS CHANCES, ESPECIALLY DURING THE AFTERNOON. PRECIPITATION
PROBABILITIES RANGE FROM 60-90% OVER THE OREGON CASCADES AND
FOOTHILLS TO 30-60% FOR THE REST OF THE REGION. HIGH
TEMPERATURES DEFLATE BACK INTO THE UPPER 50S TO LOW 60S ACROSS
THE INLAND VALLEYS SUNDAY AFTERNOON PLACING US CLOSE TO NORMAL
FOR THIS TIME OF YEAR. A HO-HUM END TO A RATHER INTERESTING
COUPLE OF DAYS. -SCHULDT
LONG TERM...MONDAY THROUGH THURSDAY
TO START THE WEEK
ENSEMBLE MODELS INDICATE THE RETURN TO BROAD WNW-NW FLOW ALOFT
WITH A WEAK EMBEDDED SHORTWAVE LIKELY MOVING OVERHEAD ON MONDAY
MAINTAINING SHOWER CHANCES (50-90%, HIGHEST CASCADES).
TEMPERATURES STAY NEAR TO SLIGHTLY BELOW SEASONAL NORMALS AS
WELL. SHOWER COVERAGE IS EXPECTED TO DECREASE MONDAY NIGHT INTO
TUESDAY MORNING THANKS TO A TRANSIENT RIDGE BRIEFLY BUILD
OVERHEAD. OUR ATTENTION THEN TURNS TO THE NEXT PACIFIC FRONTAL
SYSTEM EXPECTED TO ARRIVE SOMETIME BETWEEN LATE TUESDAY AND
WEDNESDAY WHILE DROPPING OUT OF THE GULF OF ALASKA. WHILE
TIMING DIFFERENCES PERSIST AMONG ENSEMBLE MEMBERS, CONFIDENCE
CONTINUE TO INCREASE IN THE RETURN OF WIDESPREAD PRECIPITATION
DURING THIS MID-WEEK TIMEFRAME. IT'S WORTH NOTING COOLING
TEMPERATURES ALONG AND BEHIND THE FRONTAL BOUNDARY WILL LIKELY
PUSH SNOW LEVELS TO OR JUST BELOW THE CASCADE PASSES SPARKING
RENEWED SNOWFALL CONCERNS FOR THESE AREAS, PRIMARILY DURING THE
OVERNIGHT HOURS. THE NBM SHOWS A 50-70% CHANCE FOR THE CASCADE
PASSES TO SEE 6+ INCHES OF SNOWFALL FROM 5PM TUESDAY TO 5PM
THURSDAY WITH A 10-30% FOR 12+ INCHES DURING THAT SAME PERIOD.
THIS'LL BE SOMETHING TO KEEP AN EYE ON AS WE GET INTO NEXT WEEK IN
ADDITION TO THE RETURN OF MARGINAL FROST CONCERNS MID TO LATE
WEEK AS WELL. -SCHULDT
AVIATION
GENERALLY VFR CONDITIONS ARE IN PLACE ACROSS THE
REGION WITH MID TO HIGH LEVEL CLOUDS SLOWLY MOVING FROM SOUTH TO
NORTH ACROSS THE AIRSPACE. CURRENTLY, THE LONE EXCEPTION IS KEUG
WHERE PATCHY FOG HAS DEVELOPED AND IS RESULTING IN INTERMITTENT
IFR/LIFR CONDITIONS WHICH IS EXPECTED TO LINGER THROUGH AROUND
18Z FRIDAY. EXPECT THE AIRSPACE TO REMAIN RELATIVELY DRY THROUGH
AROUND 18Z-20Z FRIDAY. AFTER THIS POINT SHOWERS AND THUNDERSTORMS
LIKELY DEVELOP AROUND LANE COUNTY BEFORE PUSHING NORTHWARD ALONG
AND EAST OF THE I-5 CORRIDOR THROUGH 03Z-06Z SATURDAY. GIVEN
DECENT MODEL CONSISTENCY, HAVE ADDED PROB30 GROUPS FOR THUNDERSTORMS
FOR KEUG, KSLE, KUAO AND KHIO AS THOSE SITES CURRENTLY HAVE THE
HIGHEST CHANCE TO SEE ACTIVITY.
CONFIDENCE REMAINS RELATIVELY LOWER (15-25% CHANCE) FOR OTHER
INLAND TERMINALS, BUT THE HIGHEST CHANCE FOR THUNDERSTORMS AT
THESE LOCATIONS IS FROM AROUND 00Z SATURDAY THROUGH 04Z SATURDAY.
THUNDERSTORM CHANCES ACROSS THE AIRSPACE RAPIDLY DECREASE AFTER
06Z FRIDAY.
IT SHOULD BE NOTED LOCATIONS THAT DO SEE STRONGER SHOWERS OR
THUNDERSTORMS WILL HAVE THE POTENTIAL FOR LIGHTNING, SMALL HAIL,
MODERATE TO HEAVY RAIN, AND GUSTY/ERRATIC OUTFLOW WIND GUSTS UP TO
45 KNOTS. THIS ACTIVITY WOULD ALSO RESULT IN INTERMITTENT MVFR/IFR
CONDITIONS IF IT MOVES DIRECTLY OVERHEAD.
AFTER 03Z-06Z SATURDAY, CONDITIONS START TO SETTLE AND WILL
RESULT IN LOWERED FLIGHT CONDITIONS WITH LINGERING SHOWERS ACROSS
THE AIRSPACE. THIS WILL BRING IFR/LIFR CONDITIONS TO THE COAST
AND VFR/MVFR CONDITIONS FOR INLAND LOCATIONS. THESE CONDITIONS ARE
EXPECTED TO PERSIST THROUGH THE END OF THE TAF PERIOD.
KPDX AND APPROACHES...EXPECT PREDOMINATELY VFR FLIGHT CONDITIONS
THROUGH THE TAF PERIOD WITH MID TO HIGH CLOUD COVER AT TIMES.
LOCALLY, SHOWER (50-70%) AND THUNDERSTORM (15-25%) CHANCES RAMP
UP AROUND 00Z SATURDAY BEFORE DIMINISHING AROUND 06Z SATURDAY.
STRONGER SHOWERS OR THUNDERSTORMS WILL HAVE THE POTENTIAL FOR
LIGHTNING, SMALL HAIL, MODERATE TO HEAVY RAIN, AND GUSTY AND
ERRATIC OUTFLOW WIND PARTICULARLY AT THE ONSET OF ACTIVITY IN THE
LATE AFTERNOON HOURS IF IT OCCURS. AFTER 07Z SATURDAY, CONDITIONS
WILL START TO SETTLE WITH A MIXTURE OF VFR/MVFR CONDITIONS THAT
WILL PERSIST THROUGH THE END OF THE TAF PERIOD. /42-99
MARINE
OVERALL CONDITIONS REMAIN RATHER BENIGN THE NEXT
SEVERAL DAYS AS NORTH TO NORTHWEST WINDS SWITCH SOUTHERLY TODAY
INTO TONIGHT BEFORE SHIFTING MORE WESTERLY BY THE START OF NEXT
WEEK. CONFIDENCE IS HIGH WIND GUSTS HOLD BELOW 20 KT THROUGH THE
MONDAY INTO MONDAY NIGHT. SEAS AROUND 4 TO 7 FT PERSIST THROUGH
THE MIDDLE OF NEXT WEEK AS WELL. IT'S WORTH QUICKLY NOTING
THERE IS A ~10% CHANCE OF THUNDERSTORMS TODAY THROUGH SATURDAY
ACROSS ALL WATERS ROTATING IN FROM THE SOUTHEAST. ANY
THUNDERSTORMS THAT DO DEVELOP COULD PRODUCE LIGHTNING HAIL,
GUSTY AND ERRATIC WINDS AS WELL AS A LESS THAN 2% CHANCE FOR A
FUNNEL CLOUD OR WATERSPOUT. OUR ATTENTION TURNS TO THE ARRIVAL
OF A DECENTLY STRONG FRONTAL BOUNDARY THE SECOND HALF OF TUESDAY
INTO WEDNESDAY LIKELY BRINGING THE RETURN OF SMALL CRAFT
ADVISORY WIND GUSTS AND SEAS AROUND 7-10 FT. -99/42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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