581
FXUS66 KSEW 100936
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
236 AM PDT WED SEP 10 2025
SYNOPSIS
AN UPPER LOW SOUTH OF THE AREA WILL CONTINUE TO
WEAKEN AND SHIFT EASTWARD. THIS WILL SPREAD MOISTURE INTO THE
REGION, WITH SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPING NEAR
THE CASCADES AND MOVING INTO THE REGION. WEAK HIGH PRESSURE
THURSDAY AND FRIDAY WILL BRING SOME DRIER CONDITIONS, BUT
ANOTHER DISTURBANCE BRINGS A RETURN OF RAIN TO THE REGION LATE
IN THE WEEKEND.
SHORT TERM /TODAY THROUGH FRIDAY/
AN UPPER LEVEL LOW CONTINUES
TO SPIN OVER THE PAC NW TODAY. SHOWERS ARE MOSTLY FOCUSED OVER
OREGON BUT WE WILL SEE ISOLATED ACTIVITY AND A FEW POSSIBLE
THUNDERSTORMS OVER THE CASCADES, NEAR THE CREST. DOWN IN THE
LOWLANDS, STRATUS CLOUDS WILL INCREASE IN COVERAGE BUT WE SHOULD
SEE SUNBREAKS THIS AFTERNOON. EXPECT HIGHS IN THE 70S WITH 60S
ALONG THE COAST.
THE UPPER LOW SLOWLY SHIFTS EAST ON THURSDAY BUT STILL REMAINS
OVER THE REGION. SHOWER COVERAGE IS AGAIN LIMITED TO THE CASCADES
WITH THUNDERSTORM CHANCES HIGHER EAST OF THE CREST. SURFACE LOW
PRESSURE WILL SHIFT INLAND FOR A STRONGER ONSHORE PUSH THURSDAY
NIGHT.
FRIDAY IS LOOKING DRY WITH HIGH PRESSURE ON THE BACKSIDE OF THE
LOW. TEMPERATURES WILL BE A LITTLE COOLER, THOUGH, WITH THICKER
STRATUS - MID 60S TO AROUND 70. 33
LONG TERM /SATURDAY THROUGH TUESDAY/
THE NEXT INCOMING PACIFIC
FRONTAL SYSTEM WILL STALL OFFSHORE ON SATURDAY, LEADING TO ONE
MORE DRY DAY. SHOWERS WILL THEN INCREASE IN COVERAGE ON SUNDAY AS
AN UPPER LEVEL TROUGH CUTS THROUGH. SHOWERS WILL LINGER INTO
MONDAY AS THE LOW DEPARTS. HIGH PRESSURE BUILDS ON TUESDAY FOR A
SLIGHT UPTICK IN TEMPERATURES. 33
AVIATION
LIGHT NORTHEASTERLY FLOW ALOFT AS AN UPPER LEVEL LOW
MOVES ACROSS THE WESTERN U.S. IFR TO LIFR MARINE STRATUS WILL
CONTINUE TO ADVANCE WESTWARD THIS MORNING. A 4-5000 FT DECK HAS ALSO
DEVELOPED OVER THE CASCADES THIS MORNING. STRATUS IS ON TRACK TO
REACH OLM, PWT, AND NEAR BLI BY AROUND 12Z, WITH STRATUS FILLING IN
AROUND THE SEATTLE METRO SHORTLY THEREAFTER. PATCHY FOG IS BEING
REPORTED AT SOME TERMINALS. THE CLOUDS SHOULD REACH THEIR GREATEST
EXTENT BY AROUND 15Z, BEFORE BEGINNING TO LIFT AND SCATTER BETWEEN
17-19Z. THE EXCEPTION BEING THE COAST, WHERE STRATUS WILL HOVER
RIGHT NEAR THE SHORELINE FOR MOST OF THE DAY. VFR CONDITIONS WILL
PREVAIL THROUGH THE REST OF THE DAY TODAY. THE PATTERN LOOKS TO
REPEAT ITSELF FOR LOW STRATUS AGAIN WEDNESDAY NIGHT INTO THURSDAY
MORNING, BUT WITH MORE UNCERTAINTY TO THE EXTENT OF STRATUS ACROSS
THE SEATTLE METRO AND NORTHWARD. WINDS ARE MOSTLY CALM THIS MORNING,
BECOMING LIGHT NORTH/NORTHWESTERLY, 5 KT OR LESS FOR MOST DURING THE
DAY TODAY.
KSEA...VFR CONDITIONS EARLY THIS MORNING. MVFR TO IFR CONDITIONS
WILL LIKELY RETURN AROUND 12Z-14Z WEDNESDAY MORNING, SCATTERING OUT
AROUND 18Z-20Z FOR A RETURN TO VFR CONDITIONS WITH SCATTERED CLOUDS
WEDNESDAY AFTERNOON. LIFR PROBABILITIES FOR THIS MORNING HAVE
DROPPED SIGNIFICANTLY (DOWN TO 10-15% BETWEEN 14-16Z), SO WILL BE A
BIT MORE GENEROUS FOR THE CEILING HEIGHTS THIS MORNING. WINDS REMAIN
NORTH-NORTHEASTERLY 4 TO 8 KT THIS MORNING, BECOMING NORTHWESTERLY
AFTER AROUND 18Z THROUGH THE REST OF THE DAY.
62
MARINE
WEAK LOW PRESSURE OVER THE PACIFIC NORTHWEST WILL BEGIN TO
MOVE INLAND WEDNESDAY WITH STRONGER ONSHORE FLOW BEHIND THE SYSTEM
ON THURSDAY. THIS WILL ALLOW FOR A PUSH OF WESTERLIES DOWN THE
STRAIT OF JUAN DE FUCA THURSDAY AFTERNOON THAT MAY REACH SMALL CRAFT
ADVISORY STRENGTH, ESPECIALLY THROUGH THE CENTRAL STRAIT. HIGH
PRESSURE WILL TRY TO NOSE INTO THE AREA FRIDAY. A FRONT WILL BEGIN
TO APPROACH THE COASTAL WATERS SATURDAY NIGHT INTO SUNDAY, WITH
MODELS BEGINNING TO SUPPORT A LOW PRESSURE SYSTEM FORMING ALONG THE
FRONT AND MOVING INTO THE PACIFIC NORTHWEST ON SUNDAY. THERE'S STILL
CONSIDERABLE MODEL DISCREPANCIES ON WHERE EXACTLY THIS LOW WILL GO,
HOWEVER, EXPECT AN INCREASE IN WINDS AND WAVES THAT COULD REQUIRE
ADDITIONAL HEADLINES GOING INTO THE LATTER HALF OF THE WEEKEND. HIGH
PRESSURE LOOKS TO REDEVELOP FOR THE BEGINNING OF NEXT WEEK.
SEAS WILL GENERALLY REMAIN IN THE 4 TO 7 FT RANGE ACROSS THE AREA
THROUGH THE REST OF THE WEEK. SEAS WILL LIKELY RISE TO THE 6 TO 8 FT
RANGE GOING INTO THE WEEKEND, THOUGH COULD APPROACH 10 FT ON SUNDAY,
DEPENDING ON THE EVOLUTION OF THE PATTERN.
62
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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