Cold in Oregon, December 30, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
214 AM PST TUE DEC 30 2014

.SYNOPSIS...AN ARCTIC FRONT HAS USHERED IN CLEAR...WINDY...AND VERY
COLD WEATHER. THE DRY COLD WEATHER PATTERN WILL CONTINUE THROUGH
MOST OF THE WEEK. THE STRONGEST WINDS WILL BE LATE TONIGHT THROUGH
TUESDAY MORNING...BECOMING MORE AND MORE CONFINED TO NEAR THE
COLUMBIA RIVER GORGE STARTING WEDNESDAY AND CONTINUING THERE INTO
FRIDAY. THE MODELS HAVE BEEN VERY INCONSISTENT AND ERRATIC WITH THE
NEXT CHANCE OF PRECIPITATION...POSSIBLY AS  EARLY AS THE END OF THIS
WEEK OR ON THIS WEEKEND...OR POSSIBLY WAITING UNTIL NEXT WEEK.

&&

.SHORT TERM...TODAY THROUGH FRIDAY...PRESSURE IS RISING QUICKLY
TONIGHT AS VERY COLD HIGH PRESSURE TAKES HOLD OVER THE AREA. THE
PRESSURE AT PDX HAS BEEN AVERAGING CLOSE TO A 1 MB RISE PER HOUR FOR
THE PAST FEW HOURS AND CURRENTLY SITS AT 1040 MB. THE 06Z NAM SHOWS
PRESSURE CONTINUING TO RISE THOUGH THIS MORNING AND TOPPING OUT AT
PDX AT AROUND 1044 MB...WHICH IS QUITE IMPRESSIVE. WINDS WILL PEAK
THIS MORNING WITH THE PEAK IN PRESSURE. TEMPERATURES HAVE DROPPED
SIGNIFICANTLY ALREADY TONIGHT WITH ALMOST THE ENTIRE FORECAST AREA AT
OR BELOW FREEZING...INCLUDING A NUMBER OF COASTAL SITES. STILL EXPECT
TEMPERATURES TO DROP INTO THE 20S EVERYWHERE EXCEPT THE IMMEDIATE
COAST...WITH SOME UPPER TEENS POSSIBLE IN THE INTERIOR VALLEY. WIND
CHILLS WILL BE IN THE SINGLE DIGITS IN THE VALLEY AND TEENS AT THE
COAST AROUND SUNRISE THIS MORNING AND WIND CHILL WARNING STILL LOOKS
GOOD FOR THE CASCADES ABOVE 3000 FT.

WHILE TONIGHT WILL BE COLD...WINDS MAY KEEP TEMPS FROM REACHING
THEIR COLDEST POTENTIAL. MORE THAN LIKELY TUESDAY NIGHT WILL BE THE
COLDEST NIGHT OF THE WEEK...WITH TEENS AND LOWER 20S COMMON IN THE
INLAND VALLEYS AND 20S AT THE COAST. LOOK FOR SINGLE DIGITS IN THE
HIGHER CASCADES.

THE UPPER LEVEL FLOW WILL DECREASE LATER THIS AFTERNOON AND TONIGHT
AND THE EASTERLY WINDS IN MANY AREAS WILL DECREASE. HOWEVER...THE
COLD ARCTIC HIGH PRESSURE WILL CONTINUE IN THE COLUMBIA BASIN...AND
THUS THE EAST WIND EVENT WILL CONTINUE BUT BECOME MORE OF A GAP FLOW
EVENT THROUGH THE GORGE AFTER THAT. THE NAM12 MODEL KEEPS A 7 TO 8 MB
GRADIENT THROUGH THE GORGE MUCH OF THE REMAINDER OF THE WEEK...THUS
EXPECT BRISK EAST WINDS TO CONTINUE IN THE GORGE AND IN THE EAST
COUNTY AREAS OF PORTLAND AND VANCOUVER THROUGH AT LEAST WEDNESDAY AND
THURSDAY AND POSSIBLY INTO FRIDAY.

DO NOT SEE MUCH IF ANY FOG THE NEXT COUPLE OF NIGHTS. WE MAY START TO
SEE SOME LOCAL FREEZING FOG DEVELOP LATE IN THE WEEK AS THE WINDS AND
DRIER AIR MASS START TO WANE. BOWEN/TOLLESON

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...STRONG UPPER LEVEL
RIDGING WILL DEVELOP OVER THE EASTERN PACIFIC LATE THIS WEEK...
KEEPING THE STORM TRACK WELL NORTH OF THE FORECAST AREA THROUGH
FRIDAY. MODELS ARE ATTEMPTING TO FLATTEN THE UPPER LEVEL RIDGE BY
SATURDAY...WHICH WILL ALLOW ZONAL ONSHORE FLOW TO DEVELOP AND PERSIST
THROUGH THE WEEKEND. THIS SHOULD SIGNAL A RETURN TO MORE SEASONAL
TEMPERATURES AND BRING A THREAT FOR PRECIPITATION. SNOW LEVELS START
OFF NEAR PASS LEVEL...SO MOUNTAIN SNOW IS EXPECTED THROUGH AT LEAST
SUNDAY BEFORE SNOW LEVELS BEGIN TO RISE. RAIN LOOKS LIKELY FOR EARLY
NEXT WEEK. /27
&&

.AVIATION...DRY EAST TO NORTHEAST WINDS HAVE SPREAD ACROSS THE
REGION AND WILL RESULT IN PREDOMINANTLY VFR CONDITIONS AT ALL TAF
SITES THROUGH 12Z WEDNESDAY. EAST WINDS WILL BE STRONGEST AT KTTD AND
KPDX...GENERALLY PEAKING IN THE 30 TO 40 KT RANGE...ALTHOUGH A GUST
OR TWO COULD END UP HIGHER...PARTICULARLY AT KTTD.

KPDX AND APPROACHES...STRONG OFFSHORE FLOW WILL PRODUCE GUSTY EAST
WINDS...GENERALLY PEAKING IN THE 30 TO 40 KT RANGE...AND VFR
CONDITIONS THROUGH 12Z WEDNESDAY. BOWEN/NEUMAN

&&

.MARINE...WINDS ARE ON TRACK TONIGHT OUT OF THE EAST TO NORTHEAST AT
15 TO 25 KT WITH GUSTS NEAR 30 KT AND WILL REMAIN FAIRLY CONSISTENT
THROUGH THIS MORNING. GUSTS SHOULD DROP BELOW SMALL CRAFT CRITERIA OF
25 KT ACROSS THE NORTHERN WATERS THIS EVENING...AND LIKELY LATE
TUESDAY NIGHT ACROSS THE CENTRAL OREGON WATERS. MODELS ARE TRYING TO
KEEP SOME GUSTS AROUND FOR THE OFFSHORE WATERS WEDNESDAY BUT IT LOOKS
MARGINAL AT THE MOMENT. LIGHT WINDS AND BENIGN SEA CONDITIONS ARE
THEN EXPECTED DURING THE SECOND HALF OF THE WORK WEEK AND EXTENDING
THROUGH THE WEEKEND. BOWEN/NEUMAN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WIND CHILL WARNING UNTIL NOON PST TODAY FOR NORTHERN OREGON
     CASCADES.

     WIND ADVISORY UNTIL 6 PM PST THIS EVENING FOR GREATER PORTLAND
     METRO AREA.

WA...WIND CHILL WARNING UNTIL NOON PST TODAY FOR SOUTH WASHINGTON
     CASCADES.

     WIND ADVISORY UNTIL 6 PM PST THIS EVENING FOR GREATER VANCOUVER
     AREA.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 9 PM PST THIS EVENING FOR
    COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60
    NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 AM PST WEDNESDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

&&

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.