093
FXUS66 KSEW 171627
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
927 AM PDT FRI JUL 17 2026
SYNOPSIS
CONDITIONS ARE FAVORED TO TREND DRIER OVER THE
WEEKEND WITH NEAR-SEASONAL TEMPERATURES. HIGH PRESSURE THEN
BUILDS OVER THE AREA NEXT WEEK, BRINGING CONTINUED DRY WEATHER
AND WELL-ABOVE AVERAGE TEMPERATURES ALONG WITH MODERATE
HEATRISK.
SHORT TERM /TODAY THROUGH SUNDAY/
WIDESPREAD STRATUS
CONTINUES THIS MORNING WITH AN UPPER LOW POSITIONED OFFSHORE OF
CAPE FLATTERY. LOW CHANCES FOR LINGERING SHOWERS REMAIN
POSSIBLE THIS MORNING AND AFTERNOON OVER THE NORTHERNMOST
PORTIONS OF THE OLYMPIC PENINSULA, OTHERWISE, DRY CONDITIONS
EXPECTED TO RESUME TODAY. FOLLOWING THE TREND ESTABLISHED 24
HOURS AGO, MODELS SEEM TO BE SLOWING DOWN THE RAMPING UP OF
TEMPERATURES IN FAVOR OF A SLOWER WARMING TREND...WHICH MAKES
SENSE GIVEN THAT THE UPPER LEVEL TROUGH ASSOCIATED WITH THE
AFOREMENTIONED LOW WILL LINGER FOR AT LEAST THE FIRST HALF OF
THE WEEKEND. AS SUCH, HIGHS TODAY WILL ONLY SEE A FEW DEGREES OF
WARMING...INTO THE LOWER TO MID 70S FOR THE INTERIOR AND MID
60S ALONG THE COAST. SATURDAY CONTINUES THIS INCREMENTAL
INCREASE WITH HIGHS GENERALLY IN THE MID 70S /STILL MID 60S FOR
THE COAST/ AND SUNDAY WARMS UP TO THE MID 70S TO NEAR 80 AS THE
COAST FINALLY STARTS TO SEE SOME MOVEMENT UPWARD, GENERALLY IN
THE MID TO UPPER 60S. AS SUCH, THIS WILL KEEP HEATRISK DOWN IN
MINOR/YELLOW THROUGHOUT THE SHORT TERM PERIOD.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
UPPER LEVEL
RIDGING OVER THE EASTERN PACIFIC STARTS TO MOVE INTO W WA SUNDAY
EVENING, AND BY THE TIME THIS FEATURE GETS ITS AXIS ALONG THE
COAST MONDAY, IT WILL FUEL A STEEP WARM-UP TO TEMPERATURES AS
MUCH AS 10 DEGREES ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.
HIGHS MONDAY RANGING GENERALLY IN THE MID 80S TO NEAR 90 WHILE
THE COAST SEES TEMPS IN THE LOWER TO MID 70S. RIDGING OVER THE
FOUR CORNERS REGION ENDS UP GETTING DRAWN NORTHWARD FOR THE
FIRST HALF OF NEXT WEEK, KEEPING CONDITIONS HOT AND DRY. HIGHS
TUESDAY LOOK TO BE THE WARMEST OF THE PERIOD WITH INLAND
TEMPERATURES IN THE UPPER 80S TO LOWER 90S. TEMPS COOL VERY
SLIGHTLY, A DEGREE OR TWO AT BEST, WITH DAYTIME HIGHS BOTH
WEDNESDAY AND THURSDAY RANGING IN THE MID TO UPPER 80S. ALL THAT
SAID, IT SHOULD NOT COME AS ANY SURPRISE THAT THIS WILL ALSO
PUSH HEATRISK HIGHER WITH WIDESPREAD MODERATE/ORANGE CONDITIONS
FOR THE INTERIOR LOWLANDS EACH DAY OF THE LONG TERM PERIOD.
TUESDAY AND WEDNESDAY ARE ALSO SHOWING ISOLATED PATCHES OF
HIGH/RED...WHICH WILL NEED TO BE MONITORED SHOULD TEMPS TREND
ANY HIGHER FOR POSSIBLE HEAT RELATED HEADLINES.
18
AVIATION
AN UPPER LEVEL LOW CENTERED JUST WEST OF CAPE
FLATTERY EARLY THIS MORNING WILL GRADUALLY LIFT NORTHWARD INTO
BRITISH COLUMBIA TODAY WITH SOUTHERLY FLOW ALOFT BECOMING
SOUTHWESTERLY TONIGHT. THE LOW LEVEL FLOW IS LIGHT ONSHORE.
WIDESPREAD LOW LEVEL MOISTURE WEST OF THE CASCADE CREST WILL
PRODUCE MOSTLY MVFR CEILINGS THROUGH AROUND 18Z BEFORE GRADUALLY
LIFTING AND SCATTERING FOR MOST AREAS THIS AFTERNOON (EXCEPT
FOR THE COAST WHERE IT MAY PROLONG INTO THE AFTERNOON). LOW MVFR
OR IFR CEILINGS ARE EXPECTED TO REDEVELOP ALONG THE COAST
TONIGHT. CONFIDENCE IN AREAL COVERAGE OF LOW CEILINGS FOR
INTERIOR AREAS SATURDAY MORNING, ESPECIALLY EAST OF PUGET SOUND,
IS LOW AT THIS TIME, BUT MVFR CHANCES AS OF THIS MORNING ARE
20-40%.
KSEA...MVFR CEILINGS ARE EXPECTED TO PERSIST THROUGH AROUND 18Z
BEFORE LIFTING AND SCATTERING OUT THIS AFTERNOON. THERE'S AROUND A
30-40% CHANCE OR SO OF MVFR CEILINGS FOR A PERIOD BETWEEN 11Z AND
17Z ON SATURDAY. SURFACE WINDS SOUTHERLY 6 KNOTS OR LESS WILL VEER
TO THE WEST/NORTHWEST BY AROUND 00Z THEN LIGHT NORTH/NORTHWESTERLY
LATE THIS EVENING.
27/HPR
MARINE
WEAK SURFACE LOW PRESSURE OVER THE COASTAL WATERS
TODAY WILL DISSIPATE ON SATURDAY AS A BROAD SURFACE RIDGE
CENTERED WELL OFFSHORE EXPANDS EASTWARD. THIS WILL LEAD TO
VARYING DEGREES OF ONSHORE FLOW INTO THE MIDDLE PORTION OF THE
COMING WEEK. THERMALLY INDUCED SURFACE LOW PRESSURE IS EXPECTED
TO EXPAND ACROSS THE INTERIOR OF WESTERN WASHINGTON MONDAY
THROUGH WEDNESDAY. AS A RESULT, DIURNALLY DRIVEN WESTERLY PUSHES
IN THE STRAIT CAN BE EXPECTED AS WELL AS OCCASIONALLY GUSTY
NORTHWESTERLIES OVER THE OUTER COASTAL WATERS WITH BOTH AREAS
REACHING SMALL CRAFT ADVISORY STRENGTH AT TIMES.
27
FIRE WEATHER
FIRE WEATHER CONCERNS WILL LINGER THROUGHOUT
THE FORECAST PERIOD AS A HOTTER AND DRIER PATTERN RETURNS
QUICKLY OVER WESTERN WASHINGTON, ESPECIALLY INTO EARLY NEXT
WEEK. THIS HAS THE POTENTIAL FOR INCREASING FIRE ACTIVITY FROM
ANY NEW LIGHTNING STARTS FROM THURSDAY'S CONVECTION.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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