FXUS66 KPQR 261017
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
218 AM PST TUE FEB 26 2013
.SYNOPSIS...HIGH PRES WILL MOVE ACROSS THE REGION TODAY. A WEAK 
FRONT WILL MOVE ACROSS THE AREA TUESDAY NIGHT AND WEDNESDAY MORNING. 
A WARM FRONT WILL APPROACH WED NIGHT AND THU...BRINGING WITH IT AN 
INFLUX OF SUB TROPICAL MOISTURE. THE WARM FRONT WILL EVENTUALLY PUSH 
THROUGH THU NIGHT OR EARLY FRIDAY.
 
&&
.SHORT TERM...STILL A FEW SHOWERS SHOWING UP ON RADAR EARLY TUE 
MORNING...MAINLY OVER THE S WA AND N OREGON CASCADES. EXPECT THESE 
TO COME TO AN END IN THE NEXT FEW HOURS AS THE UPPER RIDGE 
AXIS...SEEN JUST OFF THE COAST IN WATER VAPOR PICTURES...MOVES 
INLAND THIS MORNING. THE NEXT SHORTWAVE IN A CONTINUING PROGRESSIVE 
PATTERN WAS OUT NEAR 140 W THIS MORNING. MODELS CONTINUE TO INDICATE 
THIS WAVE TO MOVE E ACROSS WA TONIGHT. MODEL CROSS SECTIONS INDICATE 
POOR MOISTURE CONTENT WITH THE SYSTEM...BEST ACROSS THE N PART OF 
THE FORECAST AREA. AS SUCH...WILL FOCUS THE BEST POPS ACROSS THE FAR 
N TONIGHT...AND EXCLUDE POPS FROM THE S INTERIOR DUE TO LACK OF 
SUFFICIENT MOISTURE. 
A MORE WESTERLY FLOW ALOFT DEVELOPS WED...AND CONTINUES THROUGH THU. 
SATELLITE DERIVED PRECIPITABLE WATER IMAGES SHOW A PLUME OF 
PRECIPITABLE WATER VALUES IN EXCESS OF ONE INCH EXTENDING UP TO NEAR 
40 N NEAR THE DATELINE. MODELS GENERALLY AGREE ON THIS MOISTURE 
ADVECTING ENE...REACHING THE COAST WED NIGHT AND THU OVERRUNNING A 
WARM FRONT. MODEL FORECAST ISENTROPIC LIFT IS HOWEVER RATHER MODEST. 
STILL...WILL NEED TO BOOST POPS UP WED NIGHT AND THU...BUT FOR NOW 
GIVEN THE WEAK LIFT WILL LIMIT POPS TO LIKELY CATEGORY MOST AREAS... 
EXCEPT FAR N WHERE WILL ALLOW POPS INTO CATEGORICAL CATEGORY BASED 
ON BETTER EXPECTED ISENTROPIC LIFT.
.LONG TERM...MADE NO CHANGES...PREVIOUS DISCUSSION FOLLOWS...THURSDAY
NIGHT THROUGH MONDAY...AS A WEAK RIDGE BEGINS TO BUILD OVER 
CALIFORNIA AND SRN OREGON...A FRONTAL SYSTEM WILL BRING PRECIP TO 
THE FORECAST AREA LATE THURSDAY INTO FRIDAY. DRIZZLE OR LIGHT RAIN 
CAN BE EXPECTED THURSDAY NIGHT AND FRIDAY WITH THE WARM FRONT...WITH 
HEAVIER RAIN EXPECTED AS THE TRAILING COLD FRONT AND TROF AXIS MOVE 
THROUGH OVER THE WEEKEND. MODELS STILL DIFFER ON THE TIMING OF THIS 
FRONTAL PASSAGE SO HAVE KEPT A RATHER BROADBRUSHED APPROACH TO THE 
FORECAST FOR THIS TIME PERIOD. BEYOND THE WEEKEND...MODELS HAVE 
BEGUN TO ADVERTISE A SHARP RIDGE BUILDING OFFSHORE...WHICH MAY BRING 
DRYING CONDITIONS TO THE FORECAST AREA FOR THE FIRST FEW DAYS OF 
NEXT WEEK.  WILL NEED TO KEEP AN EYE ON THIS NEW DEVELOPMENT. BROWN
&&
.AVIATION...VFR CONDITIONS ACROSS NEARLY ALL THE FORECAST AREA AS OF 
10Z. INLAND VALLEYS HAVE AREAS OF CIGS 035-045...BUT EXPECT THESE 
CIGS TO BE FOCUSED ALONG THE CASCADE SLOPES AFTER 12Z. STILL A 
THREAT OF IFR VIS DUE TO FOG THROUGH 17Z AT COASTAL TAF SITES AND 
INLAND VALLEYS THAT HAVE CLEARED. EXPECT ALL AREAS TO BE VFR BY 18Z 
AND REMAIN VFR THROUGH AT LEAST 06Z WED. NEXT WEAK FRONT WILL BRING 
MVFR CONDITIONS TO THE COAST BETWEEN 06Z AND 09Z WED. 
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED AT 12Z. COULD SEE
LOCALIZED MVFR CIGS 12Z-18Z. VFR CONDITIONS RETURN BY 18Z AND
CONTINUE THROUGH THE 12Z WED. WEISHAAR
&&
.MARINE...MAIN MARINE ISSUE CONTINUES TO BE THE SMALL CRAFT
ADVISORY FOR HAZARDOUS SEAS. SEAS RUNNING A FOOT OR TWO HIGHER
THAN THE ENP GUIDANCE...AND CLOSER TO THE LOCAL SWAN OUTPUT.
LONGER-PERIOD SWELL HAS REACHED THE WATERS WITH WAVE HEIGHTS
AROUND 13 TO 15 FEET. SEAS COME DOWN TODAY...BUT WILL REMAIN JUST
ABOVE 10 FEET THROUGH AT LEAST 12Z WED. STRONGER FRONT LATE WED
AND WED NIGHT WILL CAUSE SEAS TO RISE AROUND 15 FT. SEAS EXPECTED
TO EASE BELOW 10 FT LATE IN THE WEEK. 
NEXT THREAT OF SMALL CRAFT ADVISORY WIND SPEEDS WILL BE LATE THIS
MORNING ASSOCIATED WITH THE NEXT FRONTAL SYSTEM. MODELS SUGGEST 20
KT WIND WITH GUSTS TO 25 KT DEVELOP IN PZZ270 LATE THIS MORNING
AND THEN SPREAD TO PZZ250 AROUND MIDDAY. WIND IN PZZ270 WILL EASE
AT OR SHORTLY BEFORE MIDNIGHT. NAM AND GFS HOLD ON TO SMALL CRAFT
ADVISORY WIND SPEEDS IN PZZ250 UNTIL 09Z OR SO. NEXT THREAT OF 20+
KT WIND WILL BE LATE WED NIGHT AND THU. WEISHAAR
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 10 AM THIS MORNING TO 
     MIDNIGHT PST TONIGHT FOR WATERS FROM CAPE SHOALWATER WA TO 
     CASCADE HEAD OR FROM 10 TO 60 NM.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST 
     WEDNESDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
     FLORENCE OR OUT 60 NM.
     SMALL CRAFT ADVISORY FOR WINDS FROM 1 PM THIS AFTERNOON TO 1 AM 
     PST WEDNESDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO 
     CASCADE HEAD OR OUT 10 NM.
     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST
     WEDNESDAY. 
&&
$$
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.