Thursday 11 December 2014

Extreme weather update - 12/10/2014

California braces for fiercest storm in 5 years
A ferocious storm is forecast to batter California with drenching rain, heavy snow, pounding surf and howling winds through Friday.


10 December, 2014


The National Weather Service said the barrage is "expected to be one of the strongest storms in terms of wind and rain" since storms in October 2009 and January 2008.

In Northern California, where the rain was expected to hit first, officials in San Francisco, Oakland and Marin County said schools would be closed Thursday because of expected heavy rain and winds.

Southern California saw dark clouds move in Wednesday afternoon. Los Angeles County officials closed a pair of main roads around Castaic Lake, a state recreation area in mountains north of Santa Clarita, in anticipation of mud flow.

A system fueled by the "Pineapple Express" is delivering a steady stream of moisture directly from Hawaii to the West Coast starting Wednesday. Meteorologists describe the Pineapple Express as a long, narrow plume that pipes moisture from the tropics into the western United States.

About 3-6 inches of rain is possible in parts of Northern California, including much of the San Francisco Bay Area and Sacramento, AccuWeather said. Some spots could see as much as 9 inches of rain.

The rainfall could overwhelm waterways and road drainage systems, possibly leading to flash floods.

View image on Twitter
RT@amhq: is bookending the US! We're talking about all the snow & in the west & how it'll impact drought.

In the Sacramento area, strong winds expected with the storm — gusts as high as 60 mph — could take down outdoor holiday decorations.

"I'm not putting any of it up until after the storm because even though it's pretty durable, it will just blow over," Sacramento resident Tim Adams said.

People were advised to take down their holiday lights, especially inflatable decorations that are not properly anchored.

Mark Ghilarducci, director of the California Governor's Office of Emergency Services, issued a warning that the storm will present a risk of flash flooding and debris slides, particularly in the northern and southern areas of the state that had wildfires this year.

"Burned areas are especially at risk for debris slides. Even regions that don't experience regular seasonal flooding could see flash flooding during this intense storm system," he said in a statement.

Shannon Rae Green interview Weather reporter Doyle Rice on the storm headed for the West Coast, and about how the system got its funny name. (News, USA TODAY)

The intense rain from this storm still won't end the region's drought, although it will be a major step in the right direction, AccuWeather meteorologist Alex Sosnowski said.

Runoff from the storm could cause streams to surge with high water before eventually emptying into lakes and reservoirs.

As much as 4 feet of snow could fall in the Sierra Nevada. A blizzard warning was posted for portions of the northern Sierra, where winds could rage to 80 mph with heavy, swirling snow. A winter storm warning is also in effect for the southern Sierra.

View image on Twitter
Tons of rain and snow coming on Thursday!
The weather service warned that travel in the northern Sierra will be "extremely dangerous" because of blizzard conditions: "Do not travel. If you must travel, have a winter survival kit with you. If you get stranded ... stay with your vehicle."


The storm is expected to dump enough snow on California's mountains that the state's snowpack — currently only 35% of average for this time of year — could be at 75% or higher by this weekend.

Oregon and Washington were the first to see the storm's effects Wednesday. At least 24,000 customers had lost power by Wednesday afternoon because of the rain and wind in western Washington, with more outages and rough weather forecast through Thursday.

Oddly, along with the rain in Washington came warmth, as Sea-Tac Airport hit 66 degrees, the highest December temperature ever recorded there, according to the weather service.

View image on Twitter
MT @NWSBayArea: Cool wind map Thurs AM shows storm off of CA coast. Animation: http://bit.ly/1siToc3  Pic:

UK: Power restored as 'weather bomb' storm subsides
Power has been restored to the vast majority of the 31,000 homes that had their supply cut as Scotland was hit by a storm dubbed the "weather bomb".


BBC,
10 December, 2014

Energy firm SSE said its engineers had reconnected 28,000 homes by 16:30, with a further 2,800 still without power.

Much of western and northern Scotland has been battered by wind and rain.

A wind speed of 144mph was recorded on the remote St Kilda islands, with gusts in excess of 80mph elsewhere.

Met Office amber "be prepared" warnings for the west coast and the Highlands and Islands were downgraded to yellow at 18:00 on Wednesday.

The yellow "be aware" alerts of wind, which cover the whole of Scotland, will remain in place until 10:00 on Thursday.

Ferry operator CalMac has said many of its services were likely to still be disrupted on Thursday.

An RNLI crew man who helped rescue a trawler off the coast of Orkney says the waves are "as bad as we've seen it"

The Western Isles, Shetland, Orkney and parts of Argyll and Lochaber were among the worst areas affected on Wednesday, as heavy rain, strong winds and lighting strikes left homes without power.

But disruption in much of the rest of the country was not as bad as had been feared.

SSE said about 900 customers were still without power in the Western Isles - which was left completely without electricity for a time - along with a further 270 in Shetland, 100 in Orkney, 500 in the Fort William area, 570 in Dunoon and 245 in the Oban area.

The weather was also affecting a number of other areas, causing minor damage to the electricity network.

SSE said its 500 engineers and support staff would continue working late into the night to ensure power was restored to all of the remaining households.

But it said repairs were taking longer due to the nature and complexity of the damage to the network in some places, with engineers having to contend with rain, snow, and strong winds as well as damage caused by lightning strikes.

barraBarra felt the brunt of the 'weather bomb' storm
ferry at ardrossanA Caledonian MacBrayne ferry braves the storm as it leaves Ardorssan harbour
yesnaby stormsStorms north of Yesnaby in Orkney

There were also early-morning blackouts in Renfrew, Penicuik and West Linton but power was restored by 11:30.

The rapid cyclogenesis - known colloquially as a "weather bomb" - is a deep, low-pressure system which was moving slowly eastwards between Scotland and Iceland.

Waves heights of up to 40ft (12m) battered the west coast for much of the day, with the Centre for Environment, Fisheries and Aquaculture Science saying that one of its monitoring buoys had recorded a wave of 52ft (16m) at 15:00 - the highest it had ever seen.
A series of flood warnings and alerts were also issued by the Scottish Environment Protection Agency (Sepa), but there have been no reports of major flooding.

weather graphicThis BBC graphic shows the wind strengths and wave heights from the "weather bomb"
    • The strongest wind gusts recorded so far have been 144mph on St Kilda, with South Uist at 82mph, Tiree 81mph and Islay 77mph.
    • Gusts of up to 80mph at the top station of the Cairngorm Funicular Railway.
    • The wind speed at Machrihanish on the Kintyre peninsula was recorded at 73mph, Stornoway on Lewis 69mph, and Oban 63mph.
    • The highest low-level gust so far was 79mph at Benbecula.
    • All schools, nurseries, libraries and council sports facilities in the Western Isles are closed
    • Almost 50 schools and nurseries in the Highlands are also closed, affecting 2,312 children.
    • The Skye Bridge was closed but is currently open to cars only.
    • The Forth Road Bridge, Tay Road Bridge, Erskine Bridge and Dornoch Bridge are closed to high-sided vehicles and there are warnings on the Kessock Bridge.
    • Traffic Scotland said all trunk roads were open but warned drivers to take care.
    • Many ferries have been cancelled including Cairnryan to Belfast.
    • Cairnryan to Larne sailings are operating but with delays of about two hours.
    • The Ardrossan to Brodick crossings have been cancelled, as have Kennacraig to Islay, Barra to Eriskay, Stornoway to Ullapool and Oban to Craignure.
    • All sailings on the Largs-Cumbrae service have also been cancelled due to high winds.
    • Orkney Ferries said all sailings to Westray and Sanday were cancelled for the day.
    • Mallaig to Armadale ferries cancelled today and Thursday.

    glasgow storm
Trees were brought down in Mount Florida, Glasgow, as the storm hit
The National Trust for Scotland (NTS) said the wind speed at the top of the hill on Hirta, the largest of St Kilda's islands, reached 144mph - one of the highest ever recorded there.

St Kilda, which is in the care of the NTS, experiences gales on 75 days of the year, but conditions were said to be even tougher than normal


applecrossThe shore at Applecross in Wester Ross took a battering
Earlier, the Stromness lifeboat was called out after a Spanish fishing boat radioed in a Mayday after being hit by a large wave off the west coast of Orkney.

It is understood the wheelhouse windows of the O Genita trawler were smashed in the incident, with waves bigger than the height of the boat.

By 11:40, the trawler was escorted into Pierowall Bay on Westray, by the lifeboat.
orkney
Towering waves crashed onto the cliffs in Orkney
o genitaThe O Genita trawler safely reaches Pierowall Bay after sending out a Mayday call
isle of lewis weatherA boat battles through the waves off the Isle of Lewis
The Shetland coastguard helicopter, which had been at the scene of the Mayday call, was forced to land on Westray because of lightning in the area.

Network Rail said the vast majority of the train network was running but they had withdrawn services in the more exposed areas such as coastal routes and the far north line up towards Wick and Thurso.

A number of rail services were also withdrawn, with no trains running on the following lines:

  • Inverness-Kyle/Thurso/Wick
  • Ayr-Stranraer
  • Kilwinning-Ardrossan/Largs
  • Dumbarton Central-Helensburgh Central
  • Glasgow Queen St-Oban/Fort William/Mallaig (including the Caledonian Sleeper)

saltcoats weatherCrashing waves at Saltcoats
stronsay lightningLooking west from Stronsay High School in Orkney as lightning strikes
About 20 vehicles were stuck in icy conditions at Cairn O' Mount on the B974 Banchory to Fettercairn road in Aberdeenshire for 90 minutes before being moved on at 09:30.
The Vatersay and Eriskay causeways on the Western Isles were closed after being overtopped by waves.
For the latest on the roads visit the BBC's travel news page and keep up to date with incidents and roadworks on the motorways here.
Deputy First Minister John Swinney told BBC Radio Scotland early on Thursday morning: "It is important to keep this in context. It's not a surprise that Scotland faces severe winter weather, we face it to a greater or lesser extent every year. This morning we're wrestling with a number of different issues.

"We're wrestling with very high wind speeds, which are not that uncommon in the Western Isles for example, but they are still severe and need to be prepared for.

"We're wrestling with the possibility of coastal flooding because of the sea surges and strength of waves that are likely to come, and in other parts of the country we're wrestling with the issues of snow on the A9 and M74 and we also will, I suspect, be dealing with a bit of flooding on some of the river systems in Scotland but mainly on agricultural land.

Mr Swinney added: "I think it's important to remember that this is weather which is characteristic of winter weather in Scotland and what's important is that we take the necessary steps to prepare for it."

lightning strikesThe location of lightning strikes over Scotland since midnight with thousands of homes affected by power cuts
Magicseaweed.com swell chartsA chart showing the movement of swells of up to 40ft from 06:00 to 15:00 on Wednesday


US: Winter Storm Damon: Nor'easter Brings Snow, Heavy Rain, High Winds, Coastal Flooding (FORECAST)



10 December, 2014

Winter Storm Damon continues to churn over the Northeast, and a second pulse of atmospheric energy arriving from the west is breathing new life into this extremely slow-moving nor'easter.
Areas hard-hit by Superstorm Sandy two years ago were among the first to face Damon's fury, as Tuesday morning's high tide brought minor to moderate coastal flooding to the Jersey Shore and parts of Long Island. In some areas, tides reached their highest levels since Sandy, but impacts were far less damaging this time around.
Rainfall added to the flood woes near the coast Tuesday, while ice slickened roads farther inland. Going forward, however, the biggest impact from Damon will be snow.
Setup: East Coast Storm
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Setup: East Coast Storm

    The Setup

    Low pressure formed along the western end of an old stalled frontal boundary off the Mid-Atlantic coast. It is heading north toward New England, but it may take some time to get there as it stalls out near Long Island overnight into Wednesday.
    A second batch of upper-atmospheric energy will arrive from the west, injecting fresh energy into this storm and forcing the low to lift a bit farther north or even northwestward into New England.
    This second surge of energy will also reinvigorate the storm's precipitation shield, leading to an increase in snowfall by Wednesday night and Thursday in parts of the interior Northeast and southeast Canada.
    One challenge with this system, as with most Northeast coastal storms, has been the availability and location of cold air.
    Despite the passage of a cold front through the Northeast this past weekend, the path of this coastal low dislodged the cold air (translation: air below freezing near the surface) from a significant swath of the Northeast, especially New England, causing snow and ice to change over to rain in many areas Tuesday night.
    However, on Tuesday morning, before the cold air was dislodged, up to a quarter of an inch of freezing rain was reported in Milford, New Jersey and Allamuchy, New Jersey where power lines came down. Icy conditions were also found in parts of Massachusetts where numerous car accidents occurred.
    Current Radar and Lightning
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    Current Radar and Lightning
      Thursday's Forecast
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      Thursday's Forecast
        Rain and Snow Forecast
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        Rain and Snow Forecast
        Our latest forecast additional rain and snow totals through Thursday. Note that some in the accumulating rainfall area may also see non-accumulating snowfall.
          Heavy Rain Threat
          The heaviest rain has already ended across the region but showers will be found from Philadelphia northward to New York City and southern New England. Another round of steady rain is expected farther north in Maine and northern New Hampshire on Wednesday.
          Tuesday's rainfall set daily records in, among other places, New York City (2.54 inches at Central Park); Providence, Rhode Island (2.74 inches); and Boston (2.90 inches).
          How Much Snow?
          On the western flank of the storm, rain has changed over to snow, as cold air aloft chills the column of air north and west of the I-95 corridor. Lingering pockets of snow are possible into Thursday, especially southeast of Lake Erie and Lake Ontario with some lake enhancement to the snowfall.
          Snowfall totals from Boston to New York, Philly and Washington, D.C. are expected to be minimal, if they occur at all.
          The heaviest snowfall potential will line up over the interior Northeast from northern Pennsylvania into much of upstate New York, the Green and White Mountains of Vermont and New Hampshire, and into northern Maine. Some of the higher elevations mentioned above may tally up to 2 feet of total snow, including what's already fallen, through Thursday.
          Heavy snow will also continue to affect areas across the border in southeastern Canada.
          Much of this snow is of the heavy, wet variety, making it difficult to shovel, and more prone to break tree limbs and cause power outages.
          Some of the heavy snow that fell in northern Maine, however, is being melted by rainfall and above-freezing temperatures. Farther west, particularly in upstate New York, the heaviest snow will not be followed by rain or above-freezing temperatures, so it will stick around longer.
          (FORECAST: Albany | Burlington)
          Top reported snowfall totals as of 10 a.m. Wednesday include 20 inches in Jamesville, New York (near Syracuse); 18 inches near Carrabassett Valley, Maine; 17.5 inches on Mount Mansfield in Vermont; 14 inches in Killington, Vermont; 13 inches in Lake Placid, New York, and Pinkham Notch, New Hampshire; and 6 inches in Savoy, Massachusetts.
          High Winds
          In addition, a pulse of strong winds, with some gusts from 40 to 60 mph, surged northward ahead of the developing low pressure system. This zone of strong winds has lifted from New England into Canada. These winds produced scattered power outages and knocked down tree limbs and weaker trees.
          Top reported gusts Tuesday afternoon included 62 mph in Fairhaven, Massachusetts, and 61 mph in Scituate and Falmouth, Massachusetts.
          Also, blustery winds wrapping into the cold air from upstate and central New York into central and eastern Pennsylvania through Wednesday may combine with wet, accumulating snow to trigger downed trees, tree limbs and power outages.
          This does not appear to be a crippling Northeast snowstorm with feet of snow over a widespread area.
          However, snow-covered roads in the interior Northeast will make travel challenging, and hundreds of flight delays and cancellations have been reported across the Northeast.
          Coastal Flooding
          As low pressure strengthens offshore, it generated a solid fetch of easterly winds blowing onshore across the Mid-Atlantic region. This piled ocean water toward shore, resulting in water levels of 2 to 3 feet above normal astronomical tide.
          This resulted in some coastal flooding over the Outer Banks of North Carolina, where a stretch of Highway 12 was affected Monday.
          Little Egg Inlet, New Jersey, reached major flood stage at high tide Tuesday morning, reaching its second highest level on record behind only Sandy. The Tuesday morning high tide resulted in minor to moderate coastal flooding along much of the Jersey Shore as well as portions of southern Long Island.
          The threat of coastal flooding has lessened and only minor splashover and minor beach erosion was expected along the eastern coast of New England with the high tide cycle on Wednesday morning.
          For the remainder of the storm, the strongest winds from Damon (at least in the U.S.) will be blowing offshore, so coastal flooding is no longer a concern.
          Check back with us at weather.com and The Weather Channel as we track Winter Storm Damon.



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