Damaging Wind in Oregon, January 16, 2016

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1044 AM PST SAT JAN 16 2016

.SYNOPSIS...AN UPPER LEVEL TROUGH WILL CONTINUE SHOWERS ACROSS THE
REGION TODAY. A BAND OF THUNDERSTORMS WILL LIKELY REACH THE CENTRAL
OREGON COAST LATER THIS MORNING. THERE WILL BE A BRIEF BREAK IN RAIN
TONIGHT....BUT ANOTHER ROUND OF RAIN IS ON TAP FOR SUNDAY. HERE WILL
BE ANOTHER BREAK IN RAIN SUNDAY NIGHT THROUGH MONDAY MORNING FOLLOWED
BY MORE RAIN MONDAY EVENING THROUGH TUESDAY. GENERALLY DRY ON
WED...THEN MORE RAIN THU. AHHH...JANUARY WEATHER.
&&

.UPDATE...THE BAND OF THUNDERSTORMS APPROACHING FROM THE SOUTHWEST
HAS SPLIT INTO TWO FACTIONS AS IT NEARS THE PORTLAND FORECAST AREA.
ONE OF THESE AREAS HAS REACHED THE CENTRAL OREGON COAST WHERE THERE
HAS BEEN REPORTS OF GUSTY WINDS UP TO 45
MPH...LIGHTNING...THUNDER...AND HEAVY RAIN. THE OTHER PIECE IS MORE
INLAND AND HEADING TOWARDS THE CENTRAL OREGON COAST RANGE AND SOUTH
WILLAMETTE VALLEY. HAVE UPDATED TODAY'S FORECAST TO INCLUDE A
CHANCE OF THUNDERSTORMS FOR AREAS SOUTH OF EUGENE AND A SLIGHT
CHANCE OF THUNDERSTORMS FOR THE COAST RANGE...SOUTH WILLAMETTE
VALLEY...AND LANE CASCADE FOOTHILLS THROUGH THIS AFTERNOON.

PREVIOUS UPDATE...A FRONT HAS MOVED QUICKLY ACROSS THE REGION EARLY
THIS MORNING. AS OF 830 AM THE FRONT IS OVER THE SOUTH WASHINGTON
CASCADES...BUT WELL EAST OF THE OREGON CASCADES. SHOWERS HAVE FILLED
IN BEHIND THE FRONT. THE TROUTDALE ESRL PROFILING RADAR SHOWS THE
SNOW LEVEL IS LOWERING FROM THE 7000 FEET EARLY THIS MORNING AND IS
CURRENTLY AROUND 6000 FEET. THE SNOW LEVEL WILL CONTINUE TO LOWER
TODAY AS AN UPPER LEVEL TROUGH MOVES OVER THE AREA...AND BE AROUND
4500 FEET THIS AFTERNOON

A NEGATIVELY TILTED UPPER LEVEL TROUGH IS JUST OFFSHORE THE CENTRAL
OREGON COAST THIS MORNING. A BAND OF CONVECTION WITH ABUNDANT
LIGHTNING HAS DEVELOPED NEAR THE BASE OF THE TROUGH AND IS CURRENTLY
AROUND 50 MILES SOUTHWEST OF FLORENCE OREGON. THIS BAND IS MOVING
TOWARDS FLORENCE AND WILL LIKELY REACH THE CENTRAL OREGON COAST
AROUND 10AM THIS MORNING...NEAR FLORENCE AND NEW PORT...WITH
LIGHTNING...THUNDER...ERRATIC GUSTY WINDS...AND BRIEF HEAVY RAIN
POSSIBLE.

SHOWERS WILL DECREASE THIS EVENING AND THERE WILL BE A QUICK BREAK IN
RAIN BEFORE PRECIPITATION WITH THE NEXT FRONT ARRIVES SUNDAY MORNING.
SNOW LEVELS WILL RAPIDLY RISE TO 6500 FEET SUNDAY MORNING AHEAD OF
AND DURING THE RAIN...THEN LOWER DOWN TO 4000 FEET SUNDAY NIGHT. TJ

PREVIOUS SHORT TERM...(TODAY THROUGH TUESDAY)
ANOTHER FRONT SITS OFFSHORE EARLY THIS AM...AND WILL PUSH ONSHORE
BETWEEN 6 AND 8 AM...THEN PUSHES TO CASCADES BY NOON. STEADY RAIN
WILL CONTINUE THIS AM...THEN TRANSITION TO SHOWERS LATER THIS AM.
WHILE RAINFALL HAS NOT BEEN ALL THAT HEAVY SO FAR...WITH GENERALLY
0.10 TO 0.25 INCH. BUT RAIN WILL THIS AM...WITH LOCALLY HEAVY RAIN
AT TIMES OVER THE COAST RANGE. STILL LOOK REASONABLE TO GET 1 TO 1.5
INCHES OF RAINFALL TOTALS THROUGH THIS AFTERNOON OVER THE MTNS WITH
THE HEAVIEST OVER THE COAST RANGES...AND 0.50 TO 1.00 ELSEWHERE.

SNOW LEVELS HAVE BEEN RISING THIS AM. ACCORDING TO NOAA PROFILER OVER
TROUTDALE...SNOW LEVELS WENT FROM 4000 FEET AT MIDNIGHT TO NEAR 7000
FEET AT 2 AM. THIS VERIFIED BY WATCHING THE ODOT CAMERAS FROM THE
PASSES IN THE CASCADES. SANTIAM PASS SHOWED MODERATE SNOW AT
MIDNIGHT...BUT JUST RAIN BY 2 AM. WILL SEE SNOW LEVELS REMAIN WELL
ABOVE THE PASSES THIS AM...BUT WILL SLOWLY DROP BACK DOWN TO 4500 TO
5000 FEET BY THIS EVENING.

STILL LOOKS LIKE THIS FRONT WILL PUNCH SOME GUSTY SOUTHERLY WINDS TO
THE COASTAL AREAS THIS AM INTO THIS AFTERNOON...WITH GUSTS 35 TO 45
MPH ON THE EXPOSED HEADLANDS AND OPEN BEACHES.

AS THE UPPER LOW...CURRENTLY AT 42N/132W...WILL PUSH INTO THE PAC NW
EARLY THIS AFTERNOON.  THIS WILL INCREASE SHOWERS...WITH SHOWERS
POSSIBLY CONGEALING INTO A SOLID BAND...OR EVEN FORM A PERIOD OF
STEADY RAIN. MAY HAVE TO WATCH THIS FEATURE CLOSELY TODAY. NOAA
SATELLITE IMAGERY SHOWING POTENTIAL THUNDERSTORMS FORMING TO S OF
THE FEATURE. WILL INCLUDE A SLIGHT CHANCE OF THUNDERSTORMS ON THE
COAST AND COAST WATERS FOR LATE THIS AM THROUGH THIS AFTERNOON.

SHOWERS WILL RAPIDLY DECREASE LATER THIS EVENING...WITH EVEN A DRY
PERIOD FROM LATE THIS EVENING INTO THE OVERNIGHT HOURS. BUT THAT
WILL CHANGE LATER TONIGHT AS CLOUDS INCREASE AGAIN AS ANOTHER WARM
FRONT APPROACHES. THIS WARM FRONT PUSHES INTO THE FORECAST AREA
TONIGHT AND EARLY SUN...WITH COLD FRONT PUSHING ACROSS REGION SUN
AFTERNOON. THIS SYSTEM HAS TAPPED INTO SUBTROPICAL MOISTURE. GFS AND
NAM MODELS SHOW PRECIPITABLE WATER VALUES OF 1.0 PUSHING OVER THE
REGION EARLY SUN MORNING. AS A RESULT...RAINFALL TOTALS OF 1 TO 2
INCHES OVER THE MTNS...WITH HEAVIEST OVER THE COAST MTNS...AND
GENERALLY 0.50 TO 1.00 INCH ELSEWHERE. BUT THIS SYSTEM DOE NOT LOOK
AS WINDY AS TODAYS FRONT...BUT WILL STILL BE QUITE BREEZY FOR THE
COAST WITH GUSTS 40 TO 50 MPH. WILL GET SOME SNOW IN THE
CASCADES...BUT SNOW LEVELS STILL BOUNCING AROUND PASS LEVELS...WITH
NEAR 6000 FT SUN AM AND BACK DOWN TO 4500 FT SUN NIGHT. BIT MORE IN
WAY OF INSTABILITY IN THE AFTERNOON...SO WILL KEEP SLIGHT CHANCE OF
THUNDERSTORMS OVER THE COASTAL WATERS AND COASTAL AREAS SUN
AFTERNOON AND EVENING.

MONDAY STILL LOOKS LIKE IT WILL HAVE A DRY PERIOD AS A SHORTWAVE
RIDGE TRANSITS ACROSS THE REGION. LATEST MODELS SHORTEN THE DRY
PERIOD FOR MON HOWEVER AS RAIN ENCROACHES THE COAST LATER IN THE
AFTERNOON. MODELS STILL AGREE WITH A RAIN MON NIGHT INTO EARLY TUE
AM...THEN TRANSITIONING TO SHOWERS ON TUE. SNOW LEVELS MOSTLY 4000 TO
5000 FT.					     /ROCKEY.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...THE
PROGRESSIVE PATTERN LOOKS TO CONTINUE THROUGH THE EXTENDED PERIOD.
THE MAIN DIFFERENCE WILL BE MORE MILD WEATHER SYSTEMS COMPARED TO
THOSE OF THE PAST WEEK OR SO. THE NEW ECMWF HAS COME MORE IN LINE
WITH THE GFS...ESPECIALLY REGARDING THE TUE NIGHT AND WED SYSTEM. THE
EXTENDED PERIOD STARTS WITH A DEPARTING UPPER TROUGH MON NIGHT AS
ANOTHER LOW DEEPENS NEAR 43N 135W. OFFSHORE LOW-LEVEL FLOW RETURNS
TUE. THE NEW ECMWF IS A LITTLE FASTER MOVING THE DEEPENING SURFACE
LOW TO THE COAST. BY 06Z WED THE ECMWF HAS IT NEAR BUOY 029 WHILE THE
GFS IS FURTHER WEST. THIS SYSTEM COULD BRING A SHOT OF WIND TO THE
COAST TUE NIGHT AS THE GFS SHOWS ABOUT 10 MB FROM KAST TO KOTH.
CATEGORICAL POPS TUE THROUGH TUE NIGHT WITH SNOW LEVELS NEAR THE
CASCADE PASSES. TRANSITORY UPPER RIDGE MOVES ACROSS WED AFTERNOON FOR
DECREASING POPS AND A WARMING AIR MASS. MODELS INDICATE 850 MB TEMPS
RISING TO AROUND 5C 12Z THU. BOOSTED SNOW LEVELS TO 5000 FT FAR N TO
6000 FT NEAR WILLAMETTE PASS. MODELS THEN HINT AT SOMETHING
RESEMBLING AN ATMOSPHERIC RIVER FOR THU AND FRI. ECMWF SLOWER
DRAGGING THE FRONTAL BOUNDARY THROUGH THE AREA COMPARED TO THE GFS.
IN ANY EVENT...MAX TEMPS THU SHOULD BE SEVERAL DEGREES ABOVE NORMAL.
WEISHAAR

&&

.AVIATION...PRIMARILY MIX OF VFR AND MVFR WITH MOUNTAIN
OBSCURATION ACROSS THE AREA IN POST FRONTAL SHOWERS. EXPECTING
LESS MVFR CONDITIONS AND SHOWERS THIS AFTERNOON AND EVENING AS
WEAK UPPER RIDGING AHEAD OF NEXT SYSTEM THAT ARRIVES LATER
TONIGHT. MORE WIDESPREAD MVFR TO IFR CONDITIONS POSSIBLE WITH THE
FRONTAL PASSAGE SUN MORNING.

KPDX AND APPROACHES...MVFR CIGS IN THE AREA IS EXPECTED TO IMPROVE
TO VFR AROUND 20Z WITH FEW MVFR CIGS LINGERING IN THE AREA. EAST
WINDS WILL EASE TODAY BUT RETURN LATER TONIGHT.

&&

.MARINE...TAIL END OF GALES OVER THE SOUTHERN INNER WATERS THIS
MORNING...BUT NEXT GALES ON TAP FOR TONIGHT INTO MID SUNDAY
MORNING. THERE IS A CLUSTER OF THUNDERSTORMS APPROACHING THE
SOUTHERN WATERS...ABOUT 30 TO 60 NM WEST-SOUTHEAST OF FLORENCE
THAT BEARS WATCHING.

SEAS CURRENTLY IN THE MID AND UPPER TEENS ACROSS ALL WATERS. SEAS
BRIEFLY SUBSIDE TONIGHT BUT REMAIN IN THE TEENS. ANOTHER ROUND OF
HIGH SEAS POSSIBLE LATE SUNDAY WITH SEAS LIKELY APPROACHING 20 FT.
SEAS REMAIN ELEVATED IN THE MID TEENS THROUGH THE FORECAST . /64

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH SURF ADVISORY UNTIL MIDNIGHT PST SUNDAY NIGHT
     FOR CENTRAL OREGON COAST-NORTH OREGON COAST.

WA...HIGH SURF ADVISORY UNTIL MIDNIGHT PST SUNDAY NIGHT
     FOR SOUTH WASHINGTON COAST.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
     FLORENCE OR OUT 60 NM.

     GALE WARNING FROM 10 PM THIS EVENING TO 9 AM PST
     SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
     FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST
     THIS EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA
     TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
     6 PM PST SUNDAY.
&&

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.