Full Notification

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE PORTLAND OR
157 PM PDT SAT MAR 14 2015

...PERIODS OF HEAVY RAIN WILL CONTINUE AT TIMES IN SOUTHWEST WASHINGTON AND PORTIONS OF NORTHWEST OREGON THROUGH SUNDAY EVENING...

PERIODS OF HEAVY RAIN WILL CONTINUE AT TIMES ACROSS SOUTHWEST WASHINGTON AND PORTIONS OF NORTHWEST OREGON THROUGH SUNDAY EVENING DUE TO AN ATMOSPHERIC RIVER OF MOISTURE THAT IS STREAMING IN THE PACIFIC NORTHWEST. THE PORTION OF NORTHWEST OREGON MOST AFFECTED WILL BE THE NORTH AND CENTRAL OREGON COASTS AND COASTAL MOUNTAINS NORTHEASTWARD THROUGH THE NORTH HALF OF THE WILLAMETTE VALLEY TOWARD MOUNT HOOD AND MOUNT JEFFERSON.

THROUGH EARLY SATURDAY AFTERNOON...RAINFALL AMOUNTS HAVE ALREADY EXCEEDED 2 INCHES AT A COUPLE OF LOCATIONS IN THE NORTH OREGON COAST RANGE...THE WILLAPA HILLS...AND THE SOUTH WASHINGTON CASCADES.

RAINFALL AMOUNTS THROUGH SUNDAY EVENING COULD REACH BETWEEN 3 AND 5 INCHES IN THE COASTAL MOUNTAINS AND THE CASCADES FROM MOUNT JEFFERSON NORTH THROUGH THE SOUTH WASHINGTON CASCADES. AMOUNTS ALONG THE COASTAL STRIP COULD REACH 2.5 TO AROUND 4 INCHES. AMOUNTS IN THE VALLEYS COULD REACH FROM 1.5 TO 2.5 INCHES. RAINFALL IS EXPECTED TO TAPER OFF AFTER MIDNIGHT SUNDAY NIGHT.

GOING INTO THIS HEAVY RAIN EVENT...RIVERS WERE RUNNING QUITE LOW AND THERE WAS SUBSTANTIAL ROOM IN FLOOD CONTROL PROJECTS TO CAPTURE MUCH OF THE RUNOFF. THE RECORD LOW SNOW PACK INDICATES THAT SNOW MELT WILL NOT BE A SIGNIFICANT FACTOR THIS WEEKEND. AT THIS POINT...RIVER FORECAST MODELS INDICATE THAT THE RAINFALL LOOKS TO BE INSUFFICIENT TO CAUSE WIDESPREAD RIVER FLOODING. HOWEVER...SOME SIGNIFICANT RISES ARE EXPECTED ON THE COASTAL RIVERS...AND DEPENDING ON HOW ACCURATE THE CURRENT RAINFALL FORECASTS ARE...THERE IS ALWAYS THE POSSIBILITY THAT A RIVER SUCH AS THE GRAYS RIVER IN WAHKIAKUM COUNTY WASHINGTON COULD REACH FLOOD STAGE.

IN ADDITION...SIGNIFICANT RISES ON SMALLER CREEKS AND STREAMS COULD POSE A HAZARD TO PEOPLE WHO VENTURE NEAR THOSE STREAMS.

EXTREME CAUTION IS URGED AROUND AREA RIVERS AND STREAMS THIS WEEKEND. BE SURE TO MONITOR THE LATEST WEATHER AND RIVER FORECASTS FOR THE LATEST INFORMATION ON THIS EVOLVING HEAVY RAIN EVENT.