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2 products issued by NWS for: Mount St Helens WA
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Hydrologic Outlook

HYDROLOGIC OUTLOOK
ORZ001>008-010>016-WAZ019>022-039-040-045-046-192315-

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
340 PM PST THU DEC 18 2014

...FLOODING THREAT INCREASING SATURDAY NIGHT THROUGH MONDAY FOR
NORTHWEST OREGON AND SOUTHWEST WASHINGTON RIVERS...

STRONG AND DEEP MOIST WESTERLY FLOW WILL BEGIN CROSSING THE PACNW
COAST SATURDAY MORNING. A VERY LONG FETCH OF MOISTURE IS STRETCHING
ACROSS THE PACIFIC WITH ORIGINS WEST TO THE SOUTH CHINA SEA AND HAS
ABOVE AVERAGE POTENTIAL TO BRING HEAVY RAINS TO THE AREA. AS
SUCH...THIS CONTINUES TO GIVE THE APPEARANCE OF A CLASSIC HIGH
PRECIPITATION ATMOSPHERIC RIVER EVENT WHERE THE DEEP MOIST FLOW WILL
SPEND A SIGNIFICANT AMOUNT OF TIME ON A NEARLY PERPENDICULAR COURSE
AGAINST THE COAST RANGE WITH THE CASCADES TAKING A BIT HIGHER OF THE
IMPACT. LATEST FORECASTS FOR FRIDAY NIGHT THROUGH MONDAY AFTERNOON
BRING  8 TO 12 INCHES OF RAIN TO THE CASCADES AND FOOTHILLS...7 TO
11 INCHES FOR THE COAST RANGE...5 TO 7 INCHES ALONG THE IMMEDIATE
COAST...AND 3 TO 4 INCHES ALONG THE I-5 CORRIDOR.

GIVEN LATEST DATA...IT APPEARS MULTIPLE COAST RANGE RIVERS HAVE A
MODERATE POTENTIAL OF EXCEEDING FLOOD STAGE. ADDITIONALLY...THIS
EVENT HAS SUFFICIENT DEPTH TO BRING SIGNIFICANT RAINS TO THE NORTH
OREGON AND SOUTH WASHINGTON CASCADES WHERE RIVERS WILL ALSO SEE
POTENTIAL FOR NOTABLE FLOODING.

KEEP IN MIND THAT DETAILS WILL ALWAYS BE IN FLUX UNDER THESE
SCENARIOS AS SUBTLE NORTH OR SOUTH SHIFTS COLD MAKE DRAMATIC
DIFFERENCES IN WHICH BASINS RECEIVE EXTENDED PERIODS OF MODERATE TO
HEAVY RAIN. PLEASE CONTINUE TO FOLLOW THE LATEST FORECASTS AND
IMPACTS AS CONDITIONS WARRANT.

STAY UP TO DATE WITH THE LATEST NWS FORECASTS AT
WEATHER.GOV/PORTLAND OR MOBILE.WEATHER.GOV

RIVER FORECASTS ARE AVAILABLE ON OUR WEB PAGE AT
HTTP://WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=PQR (ALL LOWER CASE)

$$



Special Weather Statement

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PORTLAND OR
337 PM PST THU DEC 18 2014

ORZ001>008-010>016-WAZ019>022-039-040-045-046-192300-
NORTH OREGON COAST-CENTRAL OREGON COAST-
COAST RANGE OF NORTHWEST OREGON-
CENTRAL COAST RANGE OF WESTERN OREGON-LOWER COLUMBIA-
GREATER PORTLAND METRO AREA-CENTRAL WILLAMETTE VALLEY-
SOUTH WILLAMETTE VALLEY-NORTHERN OREGON CASCADE FOOTHILLS-
NORTHERN OREGON CASCADES-CASCADE FOOTHILLS IN LANE COUNTY-
CASCADES IN LANE COUNTY-UPPER HOOD RIVER VALLEY-
WESTERN COLUMBIA RIVER GORGE-CENTRAL COLUMBIA RIVER GORGE-
SOUTH WASHINGTON CASCADES-WILLAPA HILLS-SOUTH WASHINGTON COAST-I-
5 CORRIDOR IN COWLITZ COUNTY-GREATER VANCOUVER AREA-
SOUTH WASHINGTON CASCADE FOOTHILLS-
INCLUDING THE CITIES OF...ASTORIA...CANNON BEACH...TILLAMOOK...
LINCOLN CITY...NEWPORT...YACHATS...FLORENCE...VERNONIA...JEWELL...
SUNSET SUMMIT...LEES CAMP...TRASK...GRANDE RONDE...BURNT WOODS...
TIDEWATER...SWISSHOME...VENETA...ST. HELENS...CLATSKANIE...
HILLSBORO...PORTLAND...WILSONVILLE...OREGON CITY...GRESHAM...
SALEM...MCMINNVILLE...WOODBURN...STAYTON...DALLAS...EUGENE...
SPRINGFIELD...CORVALLIS...ALBANY...SANDY...ESTACADA...
SILVER FALLS STATE PARK...SWEET HOME...GOVERNMENT CAMP...
DETROIT...SANTIAM PASS...VIDA...JASPER...LOWELL...COTTAGE GROVE...
MCKENZIE PASS...MCKENZIE BRIDGE...OAKRIDGE...WILLAMETTE PASS...
PARKDALE...ODELL...CORBETT...ROOSTER ROCK...MULTNOMAH FALLS...
CASCADE LOCKS...HOOD RIVER...COLDWATER RIDGE VISITORS CENTER...
MOUNT ST. HELENS...WIND RIVER VALLEY...WILLAPA...FRANCES...
ELK MOUNTAIN...RYDERWOOD...RAYMOND...LONG BEACH...OCEAN PARK...
NASELLE...CATHLAMET...LONGVIEW...KELSO...CASTLE ROCK...
VANCOUVER...BATTLE GROUND...RIDGEFIELD...WASHOUGAL...YACOLT...
AMBOY...TOUTLE...ARIEL...LAKE MERWIN...YALE LAKE...COUGAR...
CARSON...STEVENSON...UNDERWOOD
337 PM PST THU DEC 18 2014

...FLOODING THREAT INCREASING SATURDAY NIGHT THROUGH MONDAY FOR
NORTHWEST OREGON AND SOUTHWEST WASHINGTON RIVERS...

STRONG AND DEEP MOIST WESTERLY FLOW WILL BEGIN CROSSING THE PACNW
COAST SATURDAY MORNING. A VERY LONG FETCH OF MOISTURE IS STRETCHING
ACROSS THE PACIFIC WITH ORIGINS WEST TO THE SOUTH CHINA SEA AND HAS
ABOVE AVERAGE POTENTIAL TO BRING HEAVY RAINS TO THE AREA. AS
SUCH...THIS CONTINUES TO GIVE THE APPEARANCE OF A CLASSIC HIGH
PRECIPITATION ATMOSPHERIC RIVER EVENT WHERE THE DEEP MOIST FLOW WILL
SPEND A SIGNIFICANT AMOUNT OF TIME ON A NEARLY PERPENDICULAR COURSE
AGAINST THE COAST RANGE WITH THE CASCADES TAKING A BIT HIGHER OF THE
IMPACT. LATEST FORECASTS FOR FRIDAY NIGHT THROUGH MONDAY AFTERNOON
BRING  8 TO 12 INCHES OF RAIN TO THE CASCADES AND FOOTHILLS...7 TO
11 INCHES FOR THE COAST RANGE...5 TO 7 INCHES ALONG THE IMMEDIATE
COAST...AND 3 TO 4 INCHES ALONG THE I-5 CORRIDOR.

GIVEN LATEST DATA...IT APPEARS MULTIPLE COAST RANGE RIVERS HAVE A
MODERATE POTENTIAL OF EXCEEDING FLOOD STAGE. ADDITIONALLY...THIS
EVENT HAS SUFFICIENT DEPTH TO BRING SIGNIFICANT RAINS TO THE NORTH
OREGON AND SOUTH WASHINGTON CASCADES WHERE RIVERS WILL ALSO SEE
POTENTIAL FOR NOTABLE FLOODING.

KEEP IN MIND THAT DETAILS WILL ALWAYS BE IN FLUX UNDER THESE
SCENARIOS AS SUBTLE NORTH OR SOUTH SHIFTS COLD MAKE DRAMATIC
DIFFERENCES IN WHICH BASINS RECEIVE EXTENDED PERIODS OF MODERATE TO
HEAVY RAIN. PLEASE CONTINUE TO FOLLOW THE LATEST FORECASTS AND
IMPACTS AS CONDITIONS WARRANT.

STAY UP TO DATE WITH THE LATEST NWS FORECASTS AT
WEATHER.GOV/PORTLAND OR MOBILE.WEATHER.GOV

RIVER FORECASTS ARE AVAILABLE ON OUR WEB PAGE AT
HTTP://WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=PQR (ALL LOWER CASE)

$$




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