752
FXUS66 KPQR 230457
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
857 PM PST TUE JAN 22 2019
SYNOPSIS
A SERIES OF FRONTS TRAVERSING THE REGION THROUGH THE
MIDDLE OF THE WEEK WILL BRING PERIODS OF VALLEY RAIN AND MOUNTAIN
SNOW BEFORE HIGH PRESSURE BRINGS DRIER WEATHER LATE IN THE WEEK AND
THIS WEEKEND.
SHORT TERM...TONIGHT THROUGH FRIDAY
WARM FRONT WAS PUSHING INLAND
ACROSS SW WA THIS EVENING, LIFTING MOST OF THE STRATIFORM RAIN AND
SNOW ASSOCIATED WITH THE ISENTROPIC LIFT NORTH OF THE FORECAST AREA.
THE WARM FRONT WAS ALSO BRINGING A MILDER AIR MASS, MOST NOTABLY IN
RISING SNOW LEVELS OVER THE CASCADES. A FINAL BAND OF RAIN WAS SEEN
IN RADAR ALREADY MOVING INLAND OVER SW WA COAST, AND EXTENDING
OFFSHORE TO THE SW. THIS WAS PRECEDING THE COLD FRONT WHICH IS
EXPECTED DROP SE AND INLAND LATE TONIGHT. WILL LET THE ADVISORY FOR
SNOW IN THE SOUTH WA CASCADES RUN ITS COURSE THIS EVENING AND EXPIRE
AT 10 PM, BY WHICH TIME SNOW LEVELS WILL BE QUICKLY RISING TO 6K FT.
A FAIRLY STRONG LOW LEVEL ONSHORE FLOW FOLLOWS THE COLD FRONT, WHICH
WILL KEEP GOOD CHANCES FOR SHOWERS GOING INTO WED, ESP OVER WEST
FACING SLOPES WHERE OROGRAPHIC LIFT WIL BE MOST PROMINENT.
REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...WEDNESDAY INTO
WEDNESDAY NIGHT, THE OVERALL TREND WILL BE TOWARDS THE AREA DRYING
OUT. IN LOCATIONS THAT CLEAR, AREAS OF LATE NIGHT AND MORNING FOG
WILL DEVELOP WEDNESDAY NIGHT AND EARLY THURSDAY. BOTH THE ECMWF AND
GFS SHOW A SHORTWAVE MOVING THROUGH BRIEFLY SOMETIME BETWEEN
THURSDAY AFTERNOON AND FRIDAY MORNING. FOR NOW, HAVE TRENDED TOWARDS
THE ECMWF WITH THE TIMING, PUTTING SOME LOW POPS IN THE FORECAST FOR
THE POSSIBILITY OF SOME LIGHT SHOWERS WITH THE SHORTWAVE THURSDAY
DURING THE DAY, MOSTLY LIMITED TO THE CASCADE FOOTHILLS.
UPPER HIGH PRESSURE CENTERED NEAR THE CALIFORNIA COAST SHIFTS
EASTWARD BEGINNING FRIDAY, BRINGING THE RIDGE AXIS CLOSER TO THE
OREGON/WASHINGTON COAST. THIS WILL BEGIN A PERIOD OF DRY WEATHER WITH
LOWLAND LATE NIGHT/MORNING FOG. BOWEN
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
OPERATIONAL MODELS AND
THEIR ENSEMBLES ARE IN GOOD AGREEMENT THE AREA WILL REMAIN UNDER A
LARGE RIDGE INTO EARLY NEXT WEEK. THIS WILL PRODUCE A MULTI-DAY
STRETCH OF DRY WEATHER, MILD TEMPERATURES, AND AREAS OF LATE NIGHT
AND MORNING VALLEY FOG. EAST WINDS BECOME INCREASINGLY LIKELY LATE IN
THE WEEKEND INTO EARLY NEXT WEEK. MODELS DIVERGE REGARDING THE
PATTERN BY TUESDAY WITH REGARDS TO THE LOCATION OF THE RIDGE AXIS.
THERE IS SOME POSSIBILITY THAT THE RIDGE AXIS WILL MOVE BACK WEST,
ALLOWING A SHORTWAVE TO MOVE THROUGH THE LOCAL AREA, SPARKING
SHOWERS. FOR NOW, HAVE INTRODUCED SOME LOW POPS FOR TUESDAY.
IT SHOULD BE NOTED THAT MODELS SUGGEST THE FLOW WILL TURN WEAKLY
OFFSHORE SATURDAY, PARTICULARLY ALONG THE CENTRAL OREGON COAST. WITH
850MB TEMPERATURES CLIMBING INTO THE 11-13C RANGE, MANY LOCATIONS
ALONG THE COAST, IN THE COAST RANGE, AND EVEN IN THE CASCADE
FOOTHILLS WILL CLIMB INTO THE UPPER 50S TO LOW 60S. EVEN MID TO
UPPER 60S DO NOT APPEAR OUT OF THE QUESTION. WILLAMETTE VALLEY
TEMPERATURES WILL BE A LITTLE MORE TRICKY GIVEN AREAS OF MORNING FOG
COULD HAMPER TEMPERATURES. HELD TEMPERATURES ON THE WARM SIDE TO EVEN
SLIGHTLY ABOVE MODEL GUIDANCE FOR MOST AREAS, BUT STILL KEPT
TEMPERATURES WELL SHY OF RECORDS FOR NOW. RECORDS ARE POSSIBLE FOR
AREAS OF THE COAST PRONE TO DOWNSLOPE WINDS, THOUGH. BOWEN/NEUMAN
AVIATION
A WARM FRONT MOVED EAST OF THE AREA THIS EVENING.
RADAR AND SATELLITE SHOWS A WELL DEFINED COLD FRONT APPROACHING
THE NORTH OREGON AND SOUTH WASHINGTON COAST AS OF 04Z. CURRENT
TIMING HAS THE FRONT MOVING TO KPDX AND VICINITY AROUND 06Z AND
SOUTH AND EAST OF KEUG BY 09Z. AS THE FRONT MOVES THROUGH,
WIDESPREAD MVFR AND POSSIBLE IFR CONDITIONS WILL RETURN INLAND.
COASTAL AREAS ARE EXPECTED TO REMAIN IN MVFR AND IFR CATEGORY
INTO WED MORNING.
KPDX AND APPROACHES...AS OF 04Z VFR IN THE AREAS, BUT WILL LIKELY
RETURN TO MVFR WITH CIGS AROUND 2500 FEET AND REDUCED VISIBILITY
AS WELL AS THE COLD FRONT MOVES THROUGH. THERE MAY BE A SHORT
PERIODS OF IFR WITH AND AFTER THE FRONT. GENERALLY EXPECT MVFR
CIGS 1500-2500 FEET THROUGH MUCH OF WED, THROUGH MAY TREND TO LOW
VFR LATE IN THE DAY. /MH
MARINE
A GALE WARNING CONTINUES FOR THE NORTHERN MARINE ZONES
TONIGHT AS A COLD FRONT MOVES THROUGH THE WATERS. WINDS HAVE
BEEN GUSTING IN THE 30 TO 40 KT RANGE THIS EVENING AND SHOULD
EASE SOME BY MIDNIGHT. GUSTS TO 35 KT WILL LIKELY CONTINUE
THROUGH AT LEAST 2 AM WED. A FOLLOWING TROUGH REACHES THE WATERS
BY 5 AM WED WILL KEEP WINDS GUSTY BUT BELOW GALE FORCE. /MH
SEAS AROUND 8 TO 11 FT AND WILL BUILD INTO THE LOW TEENS THROUGH
THE EVENING IN RESPONSE TO THE WARM FRONTAL PASSAGE TONIGHT. A
SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR SEAS FROM THIS AFTERNOON
THROUGH WED AFTERNOON. SEAS EXPECTED TO BE NEAR OR ABOVE 10 FT
INTO EARLY THU.
AFTER THE FRONTAL PASSAGE, A BENIGN PATTERN DEVELOPS UNTIL THIS
WEEKEND. THIS WEEKEND, CURRENT OPERATIONAL MODELS SHOW A THERMAL
TROUGH DEVELOPING ALONG THE COAST IN A VERY SIMILAR MANNER TO
OUR TYPICAL SUMMER SYSTEMS. WINDS AND SEAS ARE EXPECTED TO REMAIN
BELOW ADVISORY LEVELS DURING THIS TIME, BUT SMALL CRAFT ADVISORY
WINDS COULD DEVELOP UNDER THE NORTHERLY FLOW BY THE START OF
NEXT WEEK. /42
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR SOUTH
WASHINGTON CASCADES.
PZ...GALE WARNING UNTIL 4 AM PST WEDNESDAY FOR COASTAL WATERS FROM
CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PST WEDNESDAY FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60
NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST
WEDNESDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO
FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM
PST WEDNESDAY.
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THIS AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
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