685
FXUS66 KSEW 090305
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
805 PM PDT SAT AUG 8 2026
UPDATE
A RATHER BENIGN EVENING IS IN STORE FOR WESTERN WASHINGTON AS
NO CHANGES HAVE BEEN MADE IN THIS FORECAST UPDATE. CONTINUED
ONSHORE FLOW WILL USHER IN AN ADDITIONAL ROUND OF MARINE STRATUS
OVERNIGHT INTO SUNDAY MORNING AS TRIES TO MAKE A RUN TOWARDS
PUGET SOUND. MIN TEMPS TONIGHT WILL RANGE BETWEEN THE MID 40S TO
UPPER 50S. THE PREVIOUS DISCUSSION REMAINS BELOW:
SYNOPSIS
A WEAKENING UPPER RIDGE AND INCREASING ONSHORE FLOW WILL LEAD TO
GRADUAL COOLING OVER THE WEEKEND TO NEAR NORMAL TEMPERATURES.
THIS PATTERN WILL PERSIST THROUGH THE EARLY PORTION OF THE
COMING WEEK. UNCERTAINTY IN THE FORECAST INCREASES TOWARD THE
SECOND PART OF NEXT WEEK.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/
A LITTLE MORE MARINE INFLUENCE AND MORNING HIGH CLOUD COVER HAS
RESULTED IN COOLER TEMPERATURES AROUND THE REGION AS OF EARLY
THIS AFTERNOON. ONSHORE FLOW WILL INCREASE FURTHER TODAY AND
THIS WILL RESULT IN A FEW MORE DEGREES OF COOLING FOR SUNDAY
WITH TEMPERATURES RIGHT AROUND AVERAGE FOR THE TIME OF YEAR. THE
SYNOPTIC PATTERN REMAINS FAIRLY STATIC THROUGH THE EARLY
PORTION OF THE COMING WEEK WITH ZONAL FLOW ALOFT AND LIGHT TO
MODERATE ONSHORE FLOW. THIS WILL KEEP TEMPERATURES CLOSE TO
SEASONAL NORMS WITH VARYING AMOUNTS OF STRATUS SPREADING INLAND
FROM THE COAST EACH NIGHT AND MORNING.
LONG TERM /TUESDAY THROUGH SATURDAY/
THE PATTERN TURNS A LITTLE MORE UNCERTAIN TOWARD MIDWEEK. A
NUMBER OF THE ENSEMBLES ATTEMPT TO AMPLIFY UPPER RIDGING OVER
THE EASTERN GULF OF ALASKA WITH A DOWNSTREAM TROUGH MOVING
THROUGH BRITISH COLUMBIA AROUND MIDWEEK. MORE THAN HALF OF THE
SOLUTIONS GENERATE SOME SHOWER AND/OR THUNDERSTORM ACTIVITY
OVER THE NORTH CASCADES WEDNESDAY OR THURSDAY WITH NON-WETTING
RAIN AMOUNTS. THE POTENTIAL FOR LIGHTNING IS OBVIOUSLY NOT AN
OPTIMUM FORECAST FROM A FIRE WEATHER FORECAST PERSPECTIVE, BUT
IT WILL HOLD TEMPERATURES DOWN A BIT. THEREAFTER, THERE'S BETTER
AGREEMENT AMONGST THE ENSEMBLES THAT UPPER RIDGING WILL REBUILD
OVER THE REGION. PROBABILISTIC HEATRISK PAINTS MUCH OF THE
INTERIOR LOWLANDS WITH A 40-60% CHANCE OF MODERATE HEATRISK BY
FRIDAY AND SATURDAY WITH WIDESPREAD HIGH TEMPERATURES WELL INTO
THE 80S.
27
AVIATION
WESTERLY FLOW ALOFT PREVAILS INTO SUNDAY AS AN UPPER RIDGE OVER
THE INTERIOR WEST WEAKENS SOMEWHAT. THE LOW LEVEL FLOW IS
ONSHORE. THIS WILL PULL SOME IFR STRATUS PARTWAY INLAND FROM
THE COAST LATE NIGHT INTO SUNDAY MORNING, BUT REMAIN MAINLY WEST
OF PUGET SOUND TERMINALS. THE MARINE IS EXPECTED TO BURN BACK
TO NEAR THE COAST SUNDAY MIDDAY WITH VFR CONTINUING FOR THE
REMAINDER OF THE REGION.
KSEA...MOSTLY CLEAR SKIES WILL CONTINUE INTO TONIGHT.
PROBABILITIES FOR STRATUS REACHING THE TERMINAL REMAIN FAIRLY
LOW ON SUNDAY MORNING, BUT IT'S GOTTEN CLOSE THE PREVIOUS TWO
MORNINGS. WILL LIKELY INCLUDE AT LEAST A SCATTERED LOW LAYER FOR
A FEW HOURS AFTER 12Z SUNDAY. SURFACE WINDS W/NW 7 KNOTS OR
LESS THIS AFTERNOON AND EVENING WILL BACK TO LIGHT S/SW AGAIN
OVERNIGHT.
27
MARINE
BROAD SURFACE HIGH PRESSURE WILL REMAIN CENTERED OVER THE OFFSHORE
WATERS WITH LOWER PRESSURE EAST OF THE CASCADES INTO NEXT WEEK. THIS
WILL MAINTAIN ONSHORE FLOW OVER THE NEXT SEVERAL DAYS AND BRING
DIURNALLY DRIVEN SMALL CRAFT ADVISORY STRENGTH WESTERLIES TO THE
CENTRAL AND EAST STRAIT OF JUAN DE FUCA DAILY. THE PUSH TONIGHT WILL
BE A BIT STRONGER WITH GUSTS REACHING GALES AT TIMES THIS
EVENING INTO TONIGHT.
A SERIES OF WEAK SYSTEMS PASSING TO THE NORTH OF THE AREA NEXT WEEK
WILL STRENGTHEN ONSHORE FLOW AT TIMES FOR ADDITIONAL RISKS OF GALES
ALONG THE CENTRAL AND EASTERN STRAIT.
SEAS ACROSS THE COASTAL WATERS WILL PRIMARILY PERSIST AT 4-6 FT INTO
EARLY NEXT WEEK AND MAY BECOME STEEP AT TIMES THIS WEEKEND UNDER
LOCALLY DRIVEN WINDS. SEAS WILL THEN SUBSIDE TO 2-4 FT BY TUESDAY,
BEFORE INCREASING BACK TO 4-6 FT BY MIDWEEK.
27/14
FIRE WEATHER
ONSHORE FLOW HAS KICKED INTO FULL GEAR AS MARINE AIR FUNNELS IN
ACROSS WESTERN WASHINGTON. VERY ISOLATED AREAS OF CRITICAL MIN RHS
ARE POSSIBLE IN THE CASCADE ZONES THIS AFTERNOON BUT WIDESPREAD
CONCERNS ARE NOT EXPECTED - ALLEVIATING THE THREAT FOR ELEVATED FIRE
WEATHER CONCERNS. MORE BENIGN FIRE WEATHER CONDITIONS WILL EMERGE ON
SUNDAY AND LEAD INTO THE MIDDLE NEXT WEEK. COOLER TEMPERATURES AND
INCREASED MOISTURE WITH MUCH BETTER HUMIDITY RECOVERIES ARE EXPECTED
ACROSS THE REGION. WE'RE KEEPING AN EYE ON AN UPPER-TROUGH ENTERING
THE REGION AROUND WEDNESDAY-THURSDAY. GUIDANCE HAS IT POSITIONED
MAINLY TOWARDS OUR NORTH AND EAST BUT SLIGHT (15-20%) POPS ARE
EMERGING ACROSS THE NORTH CASCADES AND CAN'T RULE OUT THE
PROBABILITY FOR A FEW STRIKES OF LIGHTNING.
41
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...GALE WARNING UNTIL 3 AM PDT SUNDAY FOR CENTRAL U.S. WATERS
STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S. WATERS STRAIT
OF JUAN DE FUCA.
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