312
FXUS66 KSEW 122156
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
256 PM PDT SUN JUL 12 2026
SYNOPSIS
AN UPPER LEVEL TROUGH WILL WEAKEN TODAY WITH HIGH PRESSURE
ALOFT WILL REBUILDING ACROSS THE REGION MONDAY INTO TUESDAY FOR
WARM AND DRIER CONDITIONS. ANOTHER WEAK TROUGH OFFSHORE WILL
TEMPORARILY COOL TEMPERATURES MIDWEEK BEFORE A LONGER TERM
WARMING TREND BEGINS TOWARD NEXT WEEKEND WITH A STRONG RIDGE OF
HIGH PRESSURE.
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/
SATELLITE IMAGERY
SHOWS PARTLY CLOUDY SKIES TO MOSTLY SUNNY SKIES ACROSS WESTERN
WASHINGTON THIS AFTERNOON. HIGH TEMPERATURES WILL WARM IN THE
LOW TO MID 70S THROUGHOUT THE AFTERNOON. AN UPPER LEVEL RIDGE
WILL NUDGE SLIGHTLY INTO THE AREA MONDAY INTO TUESDAY, PROMOTING
WARMER TEMPERATURES BACK INTO THE UPPER 70S AND LOW 80S FOR MOST
OF THE AREA MONDAY AND TUESDAY, WITH TUESDAY LIKELY BEING THE
WARMER DAY OF THE TWO. AREAS OF SEATTLE METRO AND SOUTHWARD WILL
LIKELY SEE MODERATE (ORANGE) HEATRISK ON TUESDAY - WITH ALL
OTHER PLACES ACROSS WESTERN WASHINGTON SEEING MINOR (YELLOW)
HEATRISK.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
UPPER LEVEL HEIGHTS WILL STAY RELATIVELY HIGH ON WEDNESDAY, WITH
LATEST ENSEMBLES KEYING INTO A UPPER LEVEL LOW OFFSHORE.
GUIDANCE IS STRUGGLING ON THE EXACT PATH AND STRENGTH OF THIS
CUT OFF UPPER LEVEL LOW AS OF NOW. WE WILL CONTINUE TO MONITOR
ON HOW THIS CUT OFF LOW DEVELOPS BECAUSE IT MAY INTRODUCE SOME
CONVECTION IN OUR AREA, ESPECIALLY IN THE CASCADES. FOR THE
REMAINDER OF THE WEEK, IT LOOKS LIKE STRONG UPPER LEVEL RIDGING
WILL DEVELOP WHICH WILL WARM TEMPERATURES UP ABOVE NORMAL -
HEADING INTO THE WEEKEND.
MAZURKIEWICZ
AVIATION
MORNING STRATUS HAS SCATTERED LEAVING WIDESPREAD VFR CONDITIONS
ACROSS AREA TERMINALS. THE TREND IS SLATED TO REMAIN THIS EVENING
AND INTO MONDAY MORNING AS WELL. HOWEVER, MARINE STRATUS IS SLATED
TO DEVELOP ALONG THE COAST (KHQM) AROUND 10-12Z MONDAY ALONG WITH
ISOLATED COVERAGE OVER THE INTERIOR. STRATUS IS FAVORED TO BURN OFF
BY 16-18Z ALLOWING THE RETURN OF VFR. LIGHT TO MODERATE LOW-LEVEL
ONSHORE FLOW DEVELOPING THIS EVENING WITH NORTH-NORTHWEST SURFACE
WINDS BETWEEN 5-10 KT WITH GUSTS AROUND 20 KT FOR PUGET SOUND
TERMINALS. WINDS FORECAST TO BECOME LIGHTER INTO MONDAY MORNING.
KSEA...VFR THROUGHOUT THE PERIOD. WEST-SOUTHWESTERLY SURFACE WINDS 5-
10 KT TURNING MORE FROM THE NORTHWEST BY 21-23Z WITH GUSTS UP TO 20
KT. WINDS SLATED TO BECOME MORE OUT OF THE NE AFTER 03Z BLOWING
5 KT OR LESS INTO MONDAY MORNING.
41
MARINE
SURFACE HIGH PRESSURE OVER AREA WATERS THROUGHOUT THE NEXT FEW DAYS.
DIURNAL WESTERLY WINDS THROUGH THE STRAIT OF JUAN DE FUCA WILL BE
THE MAIN THEME WITH THE NEXT BEST CHANCE OF HEADLINES ON TUESDAY
EVENING. WINDS DURING THIS TIME APPEAR TO BE SCA-LEVEL BUT GUSTS
COULD GET TO NEAR GALE STRENGTH. COASTAL WATERS MAY ALSO SEE WIND
GUSTS APPROACH 20 KT TOWARDS THE END OF THE WEEK ON THURSDAY AND
FRIDAY WITH ANOTHER LOW SYSTEM TRACKING THROUGH THE WATERS.
SEAS FOR THE MAJORITY OF THE FORECAST WILL REMAIN AT 4-6 FT, WITH
THE SYSTEM THURSDAY/FRIDAY INCREASING SEAS TO 7-8 FT WITH PERIODS
AROUND 6-8 SECONDS.
41
FIRE WEATHER
THE LACK OF OFFSHORE FLOW THROUGH THE MIDDLE OF THE WEEK WILL
KEEP FIRE WEATHER CONCERNS AT A MINIMUM. WARMING TEMPERATURES
LATER IN THE WEEK WILL BEGIN TO INCREASE THE FIRE WEATHER RISKS
GOING INTO THE WEEKEND. AN UPPER TROUGH ARRIVING AROUND MIDWEEK
WILL NEED TO BE MONITORED IN THE DAYS AHEAD FOR POTENTIAL
CONVECTION AND ASSOCIATED RISKS OF LIGHTNING STRIKES WITH FUELS
NOW RUNNING QUITE DRY.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page