Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 311658
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
958 AM PDT FRI OCT 31 2014

.SYNOPSIS..THE FRONT THAT WAS STALLED OVER THE REIGON OVERNIGHT WILL
MOVE E TODAY. AN UPPER LEVEL TROUGH OFF THE COAST THIS MORNING WILL
SLOWLY MOVE INLAND TONIGHT AND SAT BRINGING A COOL UNSTABLE AIR
MASS. SAT NIGHT AND SUN MORNING A WEAK AREA OF HIGH PRES WILL MOVE
ACROSS THE REGION...THEN A WARM FRONT COMING IN LATE SUN AND MON IS
EXPECTED TO BRING A RETURN TO WET WEATHER.
&&

.SHORT TERM...HEAVIEST RAINS ASSOCIATED WITH THE SLOW MOVING
BAROCLINIC ZONE APPEARED TO BE SHIFTING E INTO THE CASCADES THIS
MORNING...MORE IN LINE WITH THE SLOWER MOVING ECWMF AND NAM. A
SHORTWAVE SEEN IN WATER VAPOR PICTURES LIFTING N THROUGH SW OREGON
THIS MORNING WAS ENAHNCING THE RAINFALL IN THE BAROCLINIC ZONE THIS
MORNING...BUT AS IT LIFTS THROUGH TODAY IT WILL HELP PUSH THE
BAROCLINIC ZONE E. THE UPPER TROUGH WAS SEEN ALONG ABOUT 132W
LONGITUDE THIS MORNING...MAKING SLOW EASTWARD PROGRESS. WILL SEE A
TRANSITION OVER TO MORE SHOWERY PRECIPITATION TODAY...BUT WILL BACK
OFF ON THUNDER THREAT INLAND THIS AFTERNOON AS COOLEST AIR ALOFT AND
RESULTING INSTABILITY ONLY SLOWLY APPROACH THE COAST TODAY.

REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...SHOWERS OVER THE
INTERIOR SHOULD TAPER QUICKLY AS SUNSET APPROACHES THIS EVENING...
WHICH SHOULD RESULT IN MOST TRICK OR TREATERS STAYING DRY. COASTAL
LOCATIONS WILL STAND THE BEST CHANCE OF SEEING SHOWERS LINGER
THROUGH THE EVENING HOURS WHERE THE RELATIVELY WARM OCEAN SURFACE
TEMPERATURES NEARBY WILL ALLOW SHOWERS TO CONTINUE OVERNIGHT.
ADDITIONAL SHOWERS MAY BUBBLE UP SATURDAY AFTERNOON...ESPECIALLY
ACROSS THE INTERIOR...BUT IN GENERAL...THE DAY AS A WHOLE APPEARS
RELATIVELY DRY.

A WARM FRONT STILL LOOKS ON TRACK TO SPREAD LIGHT RAIN INTO OUR
NORTHERN ZONES LATE SATURDAY NIGHT...OR MORE LIKELY...SUNDAY. LIGHT
RAIN MAY LINGER WELL INTO MONDAY...ESPECIALLY ACROSS OUR NORTHERN
ZONES...BEFORE THE NEXT WET STORM SYSTEM APPROACHES THE REGION LATE
MONDAY. /NEUMAN

&&

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. MONDAY NIGHT
THROUGH THURSDAY...MODELS CONTINUE TO AGREE A STRONGER FRONTAL
SYSTEM WILL BRING A GOOD BOUT OF RAIN TO THE AREA LATE MONDAY NIGHT
INTO TUESDAY. MODELS SUGGEST SOUTHWEST WASHINGTON WILL RECEIVE THE
BRUNT OF THE HEAVIEST PRECIPITATION...WHILE QPF AMOUNTS WILL REMAIN
MUCH MORE MODEST TOWARDS LANE COUNTY. FLASHIER RIVER SYSTEMS LIKE
THE GRAYS RIVER MAY NEED TO BE MONITORED BASED ON THE LATEST MODEL
OUTPUT. POPS WERE PUSHED INTO THE LIKELY AND CATEGORICAL MENTIONS
DUE TO INCREASED CONFIDENCE IN RAIN CHANCES. WHILE THIS SYSTEM WILL
BRING WINDY CONDITIONS TO THE COAST...HIGH WINDS DO NOT APPEAR TO BE
A LARGE THREAT AT THIS POINT. BRIEF SHORTWAVE RIDGING MAY DEVELOP
FOR A DAY OR SO BEFORE THE NEXT STORM SYSTEM ARRIVES LATE IN THE
WEEK. NONETHELESS...HIGH END CHANCE TO LOW END LIKELY POPS WERE
MAINTAINED THE IN EXTENDED GIVEN UNCERTAINTY IN THE PATTERN AND
CLIMO. /NEUMAN

&&

.AVIATION...SLOW MOVING FRONT NOW GENERALLY EAST OF INTERSTATE 5
WITH ASSOCIATED PRIMARY RAIN WEAKENING AND PUSHING NORTHEAST AWAY
FROM THE TAF TERMINALS. WILL SEE WEAK TO MODERATE LOW LEVEL
INSTABILITY BUT FEEL MAIN THREAT WILL BE REDUCED VSBY UNDER THE
OCCASIONAL MODERATE SHOWER. DON`T SEE A SIGNIFICANT THREAT FOR
THUNDERSTORMS BUT DO SEE ENOUGH DEPTH TO THE LIFT FOR HAIL
POTENTIAL. WILL WAIT A FEW HOURS HOPING TO GET A BETTER IDEA FOR
LOCATION SPECIFICS BEFORE SPECIFIC TAF INCLUSION. SHOWERS SHOULD
DECREASE WITH TIME AND ESPECIALLY AFTER SUNSET TONIGHT. AS
CONVECTIVE CLOUDS CLEAR...EXPECT THERE WILL BE AREAS OF IFR VSBYS
AND CIGS DEVELOPING PROBABLY AFFECTING THE INLAND TERMINALS. EARLY
GUIDANCE...AND EXPERIENCE...SHOWS LIFR CIGS PROBABLE FOR KEUG AND
KHIO LATER OVERNIGHT.

KPDX AND APPROACHES...EXPECT VFR CIGS UNDER SHOWERS FOR THE REST
OF DAYLIGHT HOURS AND CLEARING SKIES THROUGH THE BETTER PART OF
THE NIGHT. SOME SHOWERS COULD SEE 1/4 INCH OR LESS HAIL EMBEDDED.
FEEL GUIDANCE WILL BE ON THE RIGHT TRACK SHOWING MVFR DROPPING
TO IFR CIGS DEVELOPING AOA 11Z TONIGHT. /JBONK

&&

.MARINE...WEAK SURFACE GRADIENTS AND RELATIVELY LIGHT WINDS OVER
THE WATERS FOR THE NEXT 24 HOURS WILL RESULT IN MAINLY SWELL
DRIVEN SEAS. SWELL IS ON THE INCREASE AT BUOY 89 WITH WW3 GUIDANCE
PACKAGE CONTINUING TO BRING SEAS UP ABOVE 10 FT FOR THE OUTER
WATERS AROUND NOON TODAY. THESE SEAS WILL PROPAGATE TOWARD SHORE
WITH 89 AND 050 GUIDANCE ALSO BRINGING SEAS ABOVE 10 FT. AS
SUCH...HAVE EXPANDED THE SMALL CRAFT ADVISORY FOR SEAS TO COVER
THE INNER WATERS AS WELL. LOOKS LIKE MAINLY A 12 HOUR OR LESS
EVENT WITH SWELL DROPPING BACK DOWN OVERNIGHT. NEXT IMPACT LOOKS
TO BE SUNDAY NIGHT THROUGH TUESDAY MORNING WITH A COMBINATION OF
WESTERLY SWELL AND POTENTIAL GALE WINDS PUSHING SEAS INTO THE
TEENS TO START THE WEEK. /JBONK

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PDT SAT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
     OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
     2 PM PDT THIS AFTERNOON.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 10 PM
     THIS EVENING TO 3 AM PDT SATURDAY.

&&

$$

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. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



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