Setting Up for a Stormy Week - NBC Bay Area

Setting Up for a Stormy Week

Batten down the hatches, we are in for a rainy week



    Setting Up for a Stormy Week

    We are barely into the fall season, but the forecast calls for a very winter-like week ahead.

    The National Weather Service says what is headed our way is a "potent storm system."  The storm stems from typhoon Melor, which hit Japan a few days ago.

    NBC Bay Area meteorologist Rob Mayeda says the rain will start in the North Bay Monday afternoon and will spread south by Monday night. The entire Bay Area will be wet through Wednesday.  Some areas could get several inches of rain by the time it's all over.

    The storm will also pack a punch of heavy winds with gusts reaching 60 mph.

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    The rain is enough of a threat that sand bags are being made available for San Mateo County residents who live in flood-prone areas to pick up at numerous locations around the county.

    Potential effects of the storm include mud and debris flows, flooding, downed power lines and hazardous driving conditions.

    Counties affected by the storm include San Francisco, San Mateo,  Marin, Monterey, Contra Costa, Napa, Sonoma, Santa Clara and Alameda.

    The U.S. Coast Guard also has a warning for boaters:avoid taking to the water early in the week. They recommend boaters stay away until the winds and dangerous sea conditions subside.

    If people do go out on boats, there should be a personal flotation device for each person on board, and the Coast Guard is strongly recommending  that boaters going offshore bring immersion suits or other full-body  protection because of cold water temperatures.

    From the forecast desk of Rob Mayeda:

    After Monday things make a quick u-turn into some wild and wet weather coming into the Bay Area.

    Expect rain developing in the evening with Tuesday being the focus for some very soggy and windy conditions around the Bay Area.

    This incoming system will tap into remnant moisture from former Typhoon Melor, now a batch of moisture that caught a ride in the fast moving jet stream and will be sucked into a rapidly developing low pressure system on Monday.  This may have the effect of being like steroids for a storm system..adding some extra punch, loading up the lower atmosphere with some very juicy air that will be slamming into the SW/W-facing slopes of the coastal range. 

    In this scenario -- "orographic" lift or the perpendicular airflow over places like the Santa Cruz mountains will likely mean rainfall totals approaching 5"-6" if not more in some locations.

    For the Bay Area totals in the .75" to 2" range are likely based on current expectations.  Depending on how quickly that parent surface low develops with this system winds could turn very gusty.  Its looking like we'll at least see wind advisories up around the Bay Area beginning Monday and gale warnings for the coastal areas.  Wind speeds from 15-35 for most areas on Tuesday seems like a safe bet with wind gusts nearing 60 mph+ in the hills.  Southerly winds funneling through the Salinas and southern Santa Clara valleys that may be locally higher in spots, especially in the foothill locations where wind speeds will be higher.

    Due to the time of year, many trees are still carrying a load of leaves which could set the stage for power outages and unusually widespread wind damage.  Leaves can act like mini-parachutes, and snap off limbs and large branches in higher wind gusts.  Clearing weakened branches and storm drains would be an excellent idea Sunday and early Monday.

    By Tuesday night, the heavier, widespread rain should be pushing south of Monterey with scattered showers to follow into Wednesday.  Thursday and Friday look dry, though we'll probably see increasing clouds late Friday as another, much weaker system tosses a few showers into the North Bay early next weekend.