076
FXUS66 KPQR 241009
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
309 AM PDT THU JUL 24 2008
SYNOPSIS...AFTER NEAR RECORD COOL TEMPERATURES THIS MORNING
TODAY
WILL WARM UP FAST UNDER MAINLY SUNNY SKIES INLAND. PATCHY LOW CLOUDS
WILL DEVELOP EARLY THIS MORNING...MAINLY NEAR THE NORTH COAST AND
POSSIBLY EXTEND UP THE COLUMBIA TO NEAR KELSO AND POSSIBLY BRIEFLY
THE PORTLAND METRO AREA. ANOTHER WARM AND MOSTLY SUNNY DAY IS
EXPECTED FRIDAY...BEFORE A PACIFIC FRONTAL SYSTEM STRENGTHENS ONSHORE
FLOW FOR THE DISTRICT. THIS WILL LEAD TO A COOLDOWN FOR THE
WEEKEND...ALONG WITH MORE CLOUDS AND THE POSSIBILITY OF COASTAL
DRIZZLE OR LIGHT RAIN FROM TIME TO TIME.
SHORT TERM
UPPER RIDGE BUILDING FAST OVER OREGON AND WASHINGTON
THIS MORNING AS UPPER LOW OVER SE BRITISH COLUMBIA EXITS EAST INTO
THE ROCKIES. THIS WILL RESULT IN A SIGNIFICANT WARMUP TODAY...ALONG
WITH A MUCH SHALLOWER MARINE LAYER.
BUT FIRST...TEMPERATURES ARE STARTING OFF QUITE COOL ACROSS THE
DISTRICT THIS MORNING. AS OF 2 AM TEMPS WERE ALREADY IN THE LOWER TO
MID 40S UP AND DOWN THE OREGON AND SW WASHINGTON COAST. SUSPECT 40S
WILL BE WIDESPREAD FOR MORNING LOWS INLAND AS WELL AS WINDS DIE DOWN.
CASCADES ARE COOL AS WELL...WITH BOULDER CREEK RAWS REPORTING TEMPS
IN THE UPPER 30S. WOULD NOT BE SURPRISED IF A FEW LOW TEMPERATURE
RECORDS FELL THIS MORNING...THE CURRENT RECORD LOW FOR DOWNTOWN
PORTLAND FOR JULY 24 IS 53 DEGREES...AND TEMPS WERE ALREADY INTO THE
MID 50S AS OF 2 AM THIS MORNING.
THE COOL MORNING TEMPS AND THE WARMER AIR MASS DEVELOPING ALOFT WILL
LIKELY LEAD TO A LARGE DIURNAL TEMPERATURE RANGE TODAY...WITH 30 TO
40 DEGREE SWINGS FROM MORNING LOW TO AFTERNOON HIGH COMMON ACROSS THE
DISTRICT. WITH A WARM AFTERNOON...AND A WARMER AIR MASS ALOFT...LOWS
FRI MORNING SHOULD BE A FEW DEGREES WARMER THAN THIS MORNING. UPPER
TROUGH APPROACHES THE COAST FRIDAY...BUT WILL PROBABLY BE TOO LATE TO
RESULT IN MUCH IN THE WAY OF CLOUD COVER OR SIGNIFICANT COOLING
FRIDAY. GFS/NAM SEEM TO BE DELAYING THIS UNTIL FRI NIGHT/SATURDAY...
AS SERIES OF UPPER VORT MAXES SWING THROUGH THE DISTRICT AND GENERAL
UPPER TROUGH AXIS MOVES ONSHORE. SATURDAY STILL LOOKS TO HAVE PLENTY
OF SUNSHINE INLAND...BUT THEN NAM BOUNDARY LAYER SATURATES OVERNIGHT
WITH DEEP MARINE LAYER AND PLENTY OF LOW CLOUDS SPREADING INLAND SAT
NIGHT/SUN. COASTAL DRIZZLE OR LIGHT RAIN MAY DEVELOP AS EARLY AS FRI
NIGHT AS MARINE LAYER DEEPENS...WITH ANOTHER ROUND POSSIBLE SAT
NIGHT/SUN MORNING. EXPECT MEASURABLE PRECIPITATION WILL HAVE A HARD
TIME MAKING IT EAST OF THE COAST RANGE...ESPECIALLY CONSIDERING THE
WEAK NATURE OF THE UPPER TROUGH AND CLIMATOLOGY FOR THIS TIME OF
YEAR...SO WILL LEAVE MENTION OF PRECIPITATION OUT OF FORECAST FOR THE
WILLAMETTE VALLEY AND CLARK COUNTY LOWLANDS. WEAGLE
LONG TERM
MODEL CONSENSUS SHOWS GENERAL WEST TO SOUTHWEST FLOW
ALOFT ACROSS DISTRICT THROUGH NEXT WEEK. 00Z GFS SHOWS SOME HINT OF
UPPER RIDGING BUILDING NORTH FROM THE GREAT BASIN AROUND
MIDWEEK...WITH UPPER TROUGH DEVELOPING OVER GULF OF ALASKA. EVEN WITH
AN INCREASINGLY AMPLIFIED JET PATTERN...IT STILL APPEARS GENERAL
PATTERN REMAINS ONSHORE AT THE SURFACE...PREVENTING ANY MAJOR WARMUP
NEXT WEEK. MODELS HAVE HINTED AT A FRONTAL SYSTEM APPROACHING COAST
WED/THU...BUT HAVE BEEN INCONSISTENT ON STRENGTH/TIMING UP TO THIS
POINT. WEAGLE
AVIATION
MOSTLY CLEAR OVER THE CWA THIS MORNING. LOCAL MVFR CIGS
DEVELOPING JUST NORTH OF KAST. EXPECT MVFR CIGS TO FORM ALONG THE
COAST AFTER 10Z AND MOVE UP THE COLUMBIA RIVER TO NEAR KKLS BY 12Z
AND POSSIBLY TOUCH THE KPDX AREA A FEW HOURS LATER. CIGS SHOULD
DISSIPATE INLAND BY LATE MORNING... AND LIFT ON THE COAST BY
AFTERNOON AND MOVE JUST OFFSHORE LATER THIS AFTERNOON.
KPDX AND APPROACHES...CLEAR SKIES PREVAIL THIS MORNING. AFTER
14Z...LOCAL AREAS OF MVFR CIGS MAY DEVELOP DUE TO MARINE STRATUS
ESPECIALLY WESTERN APPROACHES...BUT THEY WILL BURN OFF BY 17Z.
MARINE
HIGH PRESSURE OVER THE COASTAL WATERS WEAKENS SLIGHTLY
TODAY AS A WEAK FRONT APPROACHES FROM THE W. THE HIGH WEAKENS
SIGNIFICANTLY FRI AND SHIFTS EAST AS THE VERY WEAK FRONT MOVES OVER
THE COASTAL WATERS. HIGH PRES REBUILDS SAT AND ANOTHER FRONT
APPROACHES THE COASTAL WATERS LATE SUN. SEAS REMAIN BELOW 10 FT FOR
THE FORESEEABLE FUTURE.
PQR WATCHES/WARNINGS/ADVISORIES
OR/WA...SMALL CRAFT ADVISORY FOR WINDS FROM CASCADE HEAD TO FLORENCE
THIS AFTERNOON AND EVENING.
.PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION)
AST 0--34 PDX 000-1 SLE 000-1 EUG 000-1
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
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