140
FXUS66 KPQR 190517
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1017 PM PDT SAT JUL 18 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
A STEADY WARMING TREND WILL CONTINUE THROUGH THE
WEEKEND AS HIGH PRESSURE STRENGTHENS ACROSS THE REGION. INLAND
TEMPERATURES WILL RISE INTO THE 80S THIS WEEKEND, THEN INTO THE
UPPER 80S TO MID 90S EARLY NEXT WEEK. HOT AND DRY WEATHER IS
EXPECTED TO PERSIST THROUGH AT LEAST MIDWEEK, WITH INCREASING
HEAT IMPACTS POSSIBLE ACROSS THE INTERIOR LOWLANDS.
DISCUSSION...TONIGHT THROUGH FRIDAY
A SYNOPTIC SCALE PATTERN
SHIFT CONTINUES THROUGH THE WEEKEND AND INTO NEXT WEEK. HIGH
PRESSURE OVER THE GREAT BASIN WILL CONTINUE TO STRENGTHEN
RESULTING IN A WARMING AND DRYING TREND ACROSS THE CWA THROUGH
AT LEAST THE MIDDLE OF NEXT WEEK. WHILE HIGH PRESSURE WILL BUILD
IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE, ONSHORE
(NORTH/NORTHWEST) FLOW WILL PERSIST NEAR THE SURFACE AND PROVIDE
SOME TEMPERATURE MITIGATION, OR IN SIMPLER TERMS: ONSHORE FLOW
WILL HELP TO KEEP THE REGION SLIGHTLY COOLER. EVEN WITH ONSHORE
FLOW, INLAND TEMPERATURES WILL WARM DAY BY DAY, WHILE COASTAL
AREAS REMAIN NOTICEABLY COOLER, BUT STILL EXPERIENCE A WARMING
TREND EVEN WITH THE PERSISTENT ONSHORE FLOW.
SUNDAY, MOST INLAND LOCATIONS ARE EXPECTED TO REACH THE MID 80S
TO LOW 90S. ALONG THE COAST, HIGHS WILL REMAIN RELATIVELY COOLER,
WITH DAYTIME HIGHS IN THE MID 60S TO MID 70S. HIGHER ELEVATIONS
WILL WILL SEE DAYTIME HIGHS IN THE UPPER 70S TO UPPER
MONDAY THROUGH WEDNESDAY, THE GREAT BASIN RIDGE IS EXPECTED TO
PEAK IN STRENGTH. THIS IS RESULTING IN HIGH CONFIDENCE IN
MONDAY'S FORECAST, WITH INTERIOR LOWLAND HIGHS IN THE UPPER 80S
TO LOW 90S. THE COAST WILL HAVE HIGHS IN THE MID 60S TO MID 70S,
WITH HIGHER ELEVATIONS HAVING HIGHS IN THE UPPER 70S TO UPPER
80S. TUESDAY AND WEDNESDAY, UNCERTAINTY GROWS SIGNIFICANTLY. THE
MAJORITY OF THE UNCERTAINTY CAN BE TIED TO TWO FEATURES WITHIN
THE EASTERN PACIFIC. THE FIRST ID A LOW OFF THE CALIFORNIA
COAST, WHICH COULD DRIVE SOME MONSOONAL MOISTURE INTO THE
REGION. THE SECOND FEATURE IS WHAT TROPICAL MOISTURE REMAINS
FROM TROPICAL STORM ELIDA, WHICH IS CURRENTLY CENTERED NEAR
19.45 N/-123.57 W, WHICH PLACES IT SOUTHWEST OF THE BAJA
PENINSULA. TS ELIDA, IS FORECASTED TO WEAKEN THROUGH THE EARLY
PART OF NEXT WEEK AS IT CONTINUES TO PUSH NORTHWARD INTO THE
CENTRAL AND NORTHEASTERN PACIFIC. SO, WITH ALL THAT IN MIND,
EVEN MODEST INCREASES IN CLOUD COVER OR MOISTURE COULD EASILY
INFLUENCE AFTERNOON TEMPERATURES AND IS REFLECTED IN ENSEMBLE
GUIDANCE AS WELL AS WPC 500 MB CLUSTERS, WHICH SHOW A FAIRLY
EVEN SPREAD BETWEEN THE FOUR DIFFERENT CLUSTERS THROUGH THE
MIDDLE OF NEXT WEEK.
DESPITE THAT UNCERTAINTY, THE OVERALL MESSAGE REMAINS THE SAME:
TUESDAY AND WEDNESDAY STILL APPEAR LIKELY TO BE THE HOTTEST DAYS
OF THE PERIOD FOR MANY INLAND LOCATIONS. PROBABILISTIC GUIDANCE
CONTINUES TO SUPPORT A MODERATE TO HIGH CHANCE OF 90-DEGREE
TEMPERATURES ACROSS MUCH OF THE INTERIOR LOWLANDS, WITH THE
HIGHER ODDS ON TUESDAY AND WEDNESDAY. THERE IS ALSO A MEANINGFUL
CHANCE (20-30% CHANCE ON MONDAY, 30-50% CHANCE ON TUESDAY AND
WEDNESDAY) THAT SOME OF THE TRADITIONALLY WARMER VALLEYS PUSH
INTO THE MID 90S. WITH SEVERAL CONSECUTIVE HOT AFTERNOONS AND
ONLY LIMITED OVERNIGHT COOLING, MODERATE HEATRISK APPEARS
INCREASINGLY LIKELY FOR PORTIONS OF THE INTERIOR LOWLANDS,
ESPECIALLY FOR THOSE WITHOUT EFFECTIVE COOLING OR FOR ANYONE
SPENDING EXTENDED TIME OUTDOORS. THERE IS ALSO A LOWER-END
CHANCE (15-35%) FOR POCKETS OF MAJOR HEATRISK IF TEMPERATURES
END UP ON THE WARMER SIDE OF THE FORECAST ENVELOPE.
BY THURSDAY AND FRIDAY, GUIDANCE STILL FAVORS A SLIGHT EASING
OF THE HEAT AS THE TWO, AFOREMENTIONED SYSTEMS, COMBINED
BROADER UPPER-LEVEL LOW COMING FROM THE GULF OF ALASKA, WILL
HELP TO PUSH THE GREAT BASIN HIGH EASTWARD. EVEN WITH A PATTERN
CHANGE FOR THE LATTER PART OF NEXT WEEK, DAYTIME HIGHS LOOK TO
REMAIN A FEW DEGREES ABOVE NORMAL FOR LATE JULY. /42
AVIATION
CURRENT VFR FLYING CONDITIONS LARGELY FAVORED TO
CONTINUE THROUGHOUT THE PERIOD, ESPECIALLY AT INLAND TERMINALS.
ALONG THE COAST, RESURGENT MARINE STRATUS WILL YIELD HIGH
CHANCES OF MVFR/IFR CIGS (60-80% CHANCE) FROM 9-10Z SUN
THROUGH BY 17-21Z SUN, BEFORE LOW CLOUDS TEND TO MIX OUT AND
CONDITIONS RETURN TO VFR. NORTH TO NORTHWEST WINDS CONTINUE,
EASING TO 5 KT OR LESS TONIGHT BEFORE BUILDING TO 10-15 KT BY
MIDDAY SUNDAY, WITH GUSTS OF 20-25 KT MOST LIKELY ALONG THE
CENTRAL OR COAST. INLAND, LOW CLOUDS ARE EXPECTED TO DEVELOP
ALONG THE CASCADE FOOTHILLS, WHICH WILL SUPPORT 30-60% CHANCES
OF MVFR CIGS AT WILLAMETTE VALLEY AND PORTLAND-AREA TERMINALS,
HIGHEST TO THE EAST (KTTD), AND LOWER CLOSER TO THE I-5
CORRIDOR. ANY LOW CLOUDS WILL TEND TO MIX OUT BY 17-19Z SUN,
WITH OTHERWISE VFR CONDITIONS EXPECTED. NORTH TO NORTHWEST WINDS
WILL EASE BELOW 3-5 KT TONIGHT, THEN BUILD OT 7-12 KT BY MIDDAY
SUNDAY. GUSTS TO 20 KT ARE MOST LIKELY IN THE SOUTHERN
WILLAMETTE VALLEY (KCVO, KEUG).
KPDX AND APPROACHES...VFR CONDITIONS FAVORED THROUGHOUT THE
PERIOD, HOWEVER THERE CONTINUE TO BE 30-40% CHANCES OF MVFR CIGS
BENEATH MARINE STRATUS NEAR 2 KFT FROM 13-17Z SUN. NORTHWEST
WINDS EASE TO AROUND 3 KT TONIGHT, THEN BUILD TO 5-10 KT BY
MIDDAY SUNDAY. -36
MARINE
A TYPICAL SUMMERTIME PATTERN WILL CONTINUE THROUGH
EARLY NEXT WEEK WITH PERSISTENT NORTH TO NORTHWEST WINDS OVER
THE COASTAL WATERS. WINDS WILL BE STRONGEST DURING THE AFTERNOON
AND EVENING HOURS EACH DAY, ESPECIALLY THROUGH WEEKEND FOR THE
WATERS SOUTH OF CAPE FALCON. EXPECT WIND GUSTS UP TO 25 KT OVER
THE CENTRAL AND SOUTHERN WATERS THIS WEEKEND, WITH SEAS BECOMING
STEEP ON SUNDAY DUE TO A FRESH NORTHWEST SWELL AROUND 6-7 FT AT
7-8 SECONDS. BY SUNDAY AFTERNOON, THESE GUSTY WINDS AND STEEP
SEAS WILL EXPAND INTO THE WATERS NORTH OF CAPE FALCON. BETWEEN
THE INCREASING WINDS AND STEEPENING SEAS, CONDITIONS WILL BECOME
HAZARDOUS TO SMALL CRAFT. AS SUCH, SMALL CRAFT ADVISORIES ARE
IN EFFECT FROM SATURDAY AFTERNOON THROUGH LATE SUNDAY.
WINDS DECREASE BELOW 20 KTS EARLY MONDAY MORNING, WITH SEAS
BECOMING LESS STEEP THROUGH THE DAY MONDAY AS THE SWELL DECREASES.
BENIGN CONDITIONS EXPECTED TUESDAY INTO LATE NEXT WEEK.
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 2 PM SUNDAY TO 2 AM PDT MONDAY FOR
PZZ251-271.
SMALL CRAFT ADVISORY UNTIL 2 AM PDT MONDAY FOR PZZ252-253-272-
273.
WWW.WEATHER.GOV/PORTLAND
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