The only difference between adventure and disaster is preparedness.

Thursday, December 9, 2010

Wet Weekend Ahead

National Weather Service - Portland just had a briefing with Emergency Managers to advise about the tropical moisture headed our way.

This system is kind of a 1-2-3 punch so I will break it down that way.

Thursday night/Friday (Dec 9/10):
  • Warm, wet system creating rain heavy at times

Saturday/Sunday (Dec 11/12):
  • Strongest system of moisture
  • Freezing levels will rise from approximately 3,500' to 6,000', then to 9,000'
  • 1-3" of precipitation in Cowlitz County interior
  • Timing is fairly certain, exact location of heaviest rainfall is difficult to pinpoint
  • River levels will rise sharply on Saturday night/Sunday morning
  • Cowlitz River at Kelso is currently expected to stay about 1' below flood stage (this will be monitored closely as the location, intensity and duration of heavy rainfall can change things quickly)
  • Small stream and urban flooding is always a possibility in heavy rainfall events

Sunday evening, we can expect a break in the action as a cold front moves through. Rivers should have a small reprieve and recede slightly before Monday's system.

Monday/Tuesday (Dec 13/14):
  • Another wet/warm system bringing an additional 1-3" of rain, heavy at times.

Please remember that forecasted river levels take into account projected snowmelt associated with the rise of freezing levels. Gauged rivers in Cowlitz County can be monitored at the following links.

Weather advisories issued for Cowlitz County by NWS-Portland can be found at

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