Area Forecast Discussion
Issued by NWS Portland, OR

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FXUS66 KPQR 160352
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
848 PM PDT TUE APR 15 2014

.SYNOPSIS...A WARM FRONT WILL BRING RAIN TO SOUTHWEST WASHINGTON AND
MOST OF NORTHWEST OREGON TONIGHT AND WEDNESDAY MORNING THEN SLOWLY
LIFT NORTH WEDNESDAY AFTERNOON. THE ASSOCIATED COLD FRONT THEN MOVES
THROUGH THE AREA THURSDAY. A GRADUAL DRYING TREND OCCURS LATE IN THE
WEEK...FOLLOWED BY ANOTHER WEAK FRONTAL SYSTEM OVER THE WEEKEND.

&&

.SHORT TERM...INFRARED SATELLITE IMAGES SHOW THICKENING CLOUDS MASS
NEAR THE COAST. THE AREAS OF THE COLDEST CLOUD TOPS HAS DECREASED
SLIGHTLY OVER THE PAST FEW HOURS. THIS MAY BE AN INDICATION THE WARM
ADVECTION HAS ALREADY REACHED IT PEAK. AT LOWER LEVELS...NWS NETWORK
RADAR SHOWING RAIN JUST NORTH OF TILLAMOOK NORTH TO THE SOUTH
WASHINGTON COAST.  MODELS ARE IN GOOD AGREEMENT IN SPREADING RAIN
FROM THE NW TO THE SE OVERNIGHT AND THU MORNING.  THE OFFSHORE WARM
FRONT SHIFTS N WED AFTERNOON EASING RAIN ACROSS THE AREA...BUT NOT
QUITE ENDING ESPECIALLY FOR THE NORTHERN FORECAST ZONES.

THE FOLLOWING COLD FRONT WITH A VIGOROUS SHORT WAVE DRIVING IT AND
DEEP MOISTURE REMAINS ON TRACK FOR PASSING THROUGH NW OREGON THU.
CATEGORICAL POPS IN LINE FOR THE FRONTAL PASSAGE THU...WITH SHOWERS
FOLLOWING IMMEDIATELY BEHIND THE FRONT LATE THU AFTERNOON AS THE
SHORTWAVE CROSSES. THE POST FRONTAL SHOWERS HOWEVER LOOK SHORT LIVED
THU NIGHT AS THE DESTABILIZING COOL POOL ALOFT QUICKLY MOVES E AND
SFC HIGH PRES MOVES IN OVERNIGHT. THE HIGH PRES WITH A FLAT RIDGE
ALOFT SHOULD BRING A DRY DAY FRI.

.LONG TERM...GFS AND ECMWF COMING INTO BETTER AGREEMENT WITH
FEATURES THIS WEEKEND. SHORTWAVE AND A COLD FRONT IN WESTERLY FLOW
ALOFT IS AGREED UPON BY MODELS TO MOVE INLAND SAT. GIVEN THE GOOD
AGREEMENT IN MODELS HAVE A LITTLE MORE CONFIDENCE IN THIS
FEATURE...AND SO WILL BUMP UP POPS FOR SAT ESP ALONG THE COAST.
SIMILAR TO THE PREVIOUS SYSTEM THU AND THU NIGHT...THE COOL POOL
ALOFT IS DEPICTED TO MOVE PAST QUICKLY WITH HIGH PRES BUILDING BACK
IN. WILL DROP POPS OFF BEHIND THE FRONT FAIRLY QUICKLY SAT NIGHT....
AND SO SUN LOOKS LIKE IT IS LIKELY TO BE DRY.

AS HAS BEEN THE CASE RECENTLY...MODELS BEGIN TO DIVERGE AFTER DAY 5
LEADING TO A LACK OF CONFIDENCE IN THE MODELS FOR DAYS 6 AND 7. AS
THE FLOW APPEARS TO REMAIN PROGRESSIVE...FEEL LIKE FOLLOWING
SOMETHING CLOSE TO CLIMATOLOGY IS THE WAY TO GO FOR EARLY NEXT WEEK.
&&

.AVIATION...AN APPROACHING WARM FRONT WILL BRING GRADUALLY
LOWERING CLOUDS AND LIGHT RAIN TO THE COAST THIS EVENING...THEN
SPREAD INLAND OVERNIGHT. CIGS HAVE BEEN SLOWER TO COME DOWN THAN
EXPECTED...BUT THE LATEST FCST MODELS CONTINUE TO SHOW WIDESPREAD
MVFR WITH LOCALIZED IFR DEVELOPING AT THE COAST FROM FROM 03Z TO
06...THEN INLAND BETWEEN 06Z AND 12Z. WILL CONTINUE WITH THIS
GENERAL IDEA. LIGHT RAIN WILL LIKELY CONTINUE THROUGH
TOMORROW...WITH SOME MINIMAL LIFTING OF CIGS TOMORROW AFTERNOON.
THE BEST CHANCE FOR IMPROVEMENT TO VFR APPEARS TO BE INLAND FROM
ABOUT KSLE SOUTH. EXPECT FREQUENT MTNS OBSCURATIONS THROUGH
TOMORROW.

KPDX AND APPROACHES...EXPECT GRADUALLY LOWERING CIGS THROUGH THIS
EVENING AND OVERNIGHT AS A WARM FRONT APPROACHES. LIGHT RAIN
DEVELOPS AFTER 06Z...WITH CIGS FALLING TO MVFR SOMETIME BETWEEN
06Z AND 12Z. LIGHT RAIN WILL LIKELY CONTINUE THROUGH MOST OF
TOMORROW. THERE IS A CHANCE THAT CIGS WILL RAISE TO VFR TOMORROW
AFTERNOON. PYLE

&&

.MARINE...A WARM FRONT WILL PUSH ACROSS THE REGION LATER TONIGHT
INTO WED AM. PRES GRADIENT NOT VERY IMPRESSIVE...AND LATEST SHORT
TERM FCST MODELS INDICATE THAT BOUNDARY LAYER WINDS WILL NOT REACH
MUCH HIGHER THAN 20 KT. SO DECIDED TO CANCEL THE MARGINAL SMALL
CRAFT ADVISORY FOR WINDS THAT WAS OUT. THERE COULD BE SOME
LOCALIZED GUSTS OF 20 TO 25 KT THROUGH MIDDAY TOMORROW...BUT DO
NOT THINK THEY WILL BE WIDESPREAD ENOUGH TO JUSTIFY THE ADVISORY.
SEAS ARE EXPECTED TO RUN 7 TO 8 FT THROUGH TOMORROW.

AFTER A BIT OF A LULL TOMORROW...A STRONGER FRONT ARRIVES ON THU.
THIS FRONT APPEARS TO BRING BETTER POTENTIAL FOR WINDS GUSTING 25
KT...AND WILL LIKELY REQUIRE A SMALL CRAFT ADVISORY AS WE GET
CLOSER. SEAS SHOULD COME UP A BIT MORE WITH THIS SYSTEM...LIKELY
8 TO 10 FT THU THROUGH FRI. PYLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 AM TO
    9 AM PDT  WEDNESDAY.

&&

$$

MORE WEATHER INFORMATION ONLINE AT...
    HTTP://WEATHER.GOV/PORTLAND

INTERACT WITH US VIA SOCIAL MEDIA
    WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
    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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