Mendocino County Sheriff's Office
(Title of Crime/Incident) Message from Office of Emergency Services - Weather Shift
|Message from Office of Emergency Services - Weather Shift|
|When:||Date:||November 27, 2012||Time:|
|Victim Info :|
|Written by:||Executive Coordinator Liz Evangelatos|
|Synopsis:||A major shift in the weather pattern will bring wet and windy weather to all of Northern and Central California beginning midweek and lasting through the weekend and into the beginning of next week. Heavy precipitation is expected across northern portions of the state with high rainfall rates first on Wednesday then again on Friday into Saturday. Urban and small stream flooding will be common, even extending into central California. Regarding main stem rivers, this event will be the largest of the season to date, and rapid rises on some rivers can be expected, but for the most part remain below levels of serious concern. Meanwhile mud and debris flows are possible especially near areas burned during recent wildfires.
Flood control reservoirs are all in excellent shape with storage's well below the "top of conservation" managed by the USACE. See http://cdec.water.ca.gov/cdecapp/resapp/GetDailyFCgraphs.action for a nice graphic on reservoir flood control space. Bottom line: "There is plenty of room in the flood control reservoirs."
Rain and gusty winds are expected in southern California but to a lesser degree.
One of the biggest concerns revolves around what comes next. This storm sequence should wet basins down pretty well, making subsequent events much more effective, and the long-range guidance suggests that the storm door is remaining open.
· Beginning Wednesday
· Most intense Thursday through Friday night
· Ending late Sunday/Monday.
· Pattern remains unsettled through next week
HEAVY RAIN STORM TOTAL AMOUNTS
· Northwest Coast 5 to 10" rain with 12 to 16" rain upslope prone areas
· Mountains 4 to 14" rain heaviest Lassen Park and Shasta County (snow above 7,000 feet)
· Foothills 6 to 12" rain heaviest Feather River Basin and Shasta County Foothills
· Valley Floor 4 to 7" rain northern half Sacramento Valley and 1 to 4" elsewhere extending south into Central California
· Southern Mountains 1 to 2" rain with lesser amounts at lower elevations
· Strongest winds Thursday Through Saturday
· Mountains Southerly 25 to 50 gusting to 60 MPH
· Foothills Southerly 25 to 35 gusting to 50 MPH
· Valley Floor Southerly 25 to 35 gusting to 45 MPH (including those east of the Sierra such as the Owens Valley)
· Ocean Southerly 25 to 35 gusting to over 50KTS
· Mud and debris flows likely around burn scarred areas (Shasta, Butte, and Plumas Co's)
· Local power outages due to downed limbs and trees
· Flooding of poorly drained areas...including streets and highways during intense rainfall
· Smaller, unregulated streams will see rapid rises and local flooding is expected
· Main stem river rises beginning Thursday
· Wind generated ocean swells 5 to 8 feet and surf 6 to 10 feet on west facing south coastal areas
Confidence is high in both the timing and magnitude of the event.
|Approved By:||Executive Coordinator Liz Evangelatos|