Persistent Alaska warmth this fall has brought back ‘the blob.’ If it lasts, it could mean a wild winter in the Lower 48. ~ The Washington Post


Sea surface temperature anomalies highlight the expansive blob of warm water around Alaska. (earth.nullschool.net)
October 18 at 2:07 PM

Throughout early fall, Alaska has been oddly warm and pleasant. The cause of the freakishly nice weather has been massive high pressure anchored over and around the state. One of the strongest on record for fall, this sprawling dome of warm air has helped keep the usual transition to cold stunted.

Since days are still long in early fall across Alaska, the sunny September (and into October) skies have also allowed ocean temperatures in the Northeast Pacific to rise significantly, as well. This has led to a return pool of abnormally warm ocean water in the Northeast Pacific known as “the blob,” and just in time for Halloween!

But scientists are unsure whether the blob will remain a fixture or fade away. If it manages to linger into the winter, the consequences for the Lower 48 could be profound.

[NOAA winter outlook: El Niño may mean stormy conditions in the South and Eastern U.S.]

Although the blob is focused over the Northeast Pacific and the Gulf of Alaska, it has played a substantial role in the development of extreme weather patterns over the Lower 48 when it has formed in the past. Generally, it has been linked to abnormally warm and dry conditions in the West, and cold and stormy conditions in the East.

When the blob is in place, the jet stream, which both divides warm and cold air and acts as super highway for storms, tends to veer north over the top of the blob. This results in a big ridge of high pressure forming over western North America, which brings mild weather and blocks storms.

The blob’s presence was linked to the persistence and intensity of the drought in California from 2013 to 2015. It also ″was blamed for contributing to 2015 being the hottest year on record in Seattle,” according to Scott Sistek, a meteorologist with KOMO in Seattle.

As the cold air displaced by the blob has to go somewhere, it then often crashes south in the East. Remember the polar vortex intrusions during the winters of 2013-2014 and 2014-2015? The blob played a role.

So what will happen to the current iteration of the blob?

After Alaska’s stunningly sunny September, warmer-than-normal conditions have persisted into October, despite some change in the pattern, which is now delivering more in the way of clouds and precipitation.

While the National Weather Service Climate Prediction Center is forecasting warmer-than-normal conditions for Alaska the rest of the month, the mega-high-pressure zone feeding the blob is expected to continue to shift and break down a bit. In its wake, a stormier pattern may take over, at least for a time. This would allow the waters where the blob currently resides to begin to mix better, perhaps ultimately diminishing or even destroying it.

“How long will BLOB Jr. last? At least as long as we have persistent high pressure over the north Pacific,” wrote Cliff Mass, a professor of atmospheric science at the University of Washington, in a blog post. At this point, “it looks like things are evolving to a pattern with less high pressure offshore, so the BLOB should weaken.”


Over the next week, weather modeling indicates high pressure will move east into Canada as low pressure moves into the region where the blob is hanging out. (Tropical Tidbits)

According to Brian Brettschneider, a climatologist in Alaska, even if high pressure persists, it may turn into a source of cold air rather than warmth given Alaska’s waning sunlight — which would weaken the blob.

Ultimately, it’s hard to say much conclusively about the blob’s fate.

The blob last showed up around this time in 2016. Back then, there was some thinking that it may lead to a new round of winter cold outbreaks in the East. That didn’t really happen, as the blob dissipated.

Blob or not, the damage has been done in Alaska, where drought persists in the coastal rain forest of the southeast, and it’s been an extraordinarily peculiar start to the cold season.

“The onset of autumn in Alaska — the wettest part of the year for south-central and southeast Alaska — has been slow to arrive by four weeks or so,” said Dave Snider of the National Weather Service forecast office in Anchorage.

Anchorage has yet to witness a freeze. Although the city could see its first freeze in about a week, that will be about 10 days to two weeks past the old record for latest, a substantial gap.

“Nome should have 20 freezes by now. This year just one,” Brettschneider said. “Anchorage should have 20 days with temperatures below 38 degrees. This year, zero. So it’s not just the lack of a freeze, it’s that everything about the air mass is exceptional and persistent.”

Another oddity? Fairbanks has yet to see any snow so far this season, the latest on record. But history shows that the lack of snow so far means little with respect to what winter will bring.

Screen Shot 2018-10-18 at 2.17.50 PM.png

Much like the future of the blob, the future of winter in Alaska is very much to be determined.

Brettschneider sees the potential for a perfect confluence of conditions to keep the warmth coming. Since September turned to October, a dominant feature has been a low pressure area in the Bering Sea. This is a conduit for driving relatively mild Pacific Ocean air into the state.

It’s still quite early in the cold season, even in the snowy north. For now, it’s a waiting game. Waiting for summer to finally end, and waiting to see what winter might bring. It won’t only have implications for Alaska, but for all of us.

snow likely this week and next above TL

OPENSNOW

We’ll see lots of rain showers this week, October 1-5, then the weather pattern will become colder and we will likely see a bit of snow on October 5-6 and a better chance for potentially significant snow between October 6-10.

Short Term Forecast

The perfectly sunny and dry days of September are now behind us and the weather pattern will become more active for at least the next two weeks.

On Monday, expect a cloudier day, though we’ll likely stay mostly dry.

Then on Tuesday and Wednesday, moisture from the remnants of Hurricane Rosa will bring showers. Not every mountain area will receive significant rain, though some spots will receive 1-2+ inches of rain, which is significant.

During the end of the week, on Thursday and Friday, the showers will continue.

Total precipitation for this week (Monday, October 1 through Friday, October 5) could be significant over the mountains.

While we could see a lot of precipitation this week (image above), we will NOT see a lot of snow.

The snow forecast for the week shows just light amounts over Colorado. This is because temperatures will be very warm until about Friday, so most of the week’s precipitation will fall as rain with only the highest peaks seeing snowflakes.

If you want to see snowflakes at ski-area elevations, keep your eye on the time between Friday and Saturday when cooler air will finally arrive.

Recap for this week – a good chance for significant rain Tuesday, Wednesday, and Thursday, then Friday and Saturday will bring cooler temperatures and perhaps a bit of snow.

Extended Forecast

Snow between October 6-10.

NOAA’s forecast (which is the average of many models) shows a good chance for above average precipitation.

And, the most important part, is that NOAA’s forecast also shows a good chance for colder-than-average temperatures.

The combination of above average precipitation and colder-than-average temperatures in October in Colorado is a recipe for snow, so my eye is on the time between October 6-10 as a likely period that our mountains could see the first significant snowfall of the season.

Let’s look in detail at Crested Butte, which I choose because it’s roughly in the middle of Colorado’s mountains. With the storm still 6+ days away and the forecast likely to change, we should look at generalities rather than focus on a particular corner of the state.

In the graphic below, each horizontal line shows the snow forecast from one of the 51 versions of the European model.

I highlighted in red the period from October 6-10. What’s awesome is that nearly every model version (each horizontal line) shows at least some snow, and about 50% of the model versions show significant snow.

This is plenty of evidence for me to say that either this weekend or next week will likely be the time when at least some of Colorado’s mountains get their first significant snowfall.

Of course, the details of this forecast will change daily between now and then, so let’s not get too excited for a specific amount of snow at a single location. Rather, the takeaway is that this week will be rainy, and then the upcoming weekend and next week will be much cooler with snow likely.

Farmer’s Almanac 2018-19 Winter Forecast from Open Snow

The Farmer’s Almanac publishes forecasts every August that look ahead to the upcoming winter season. These are widely circulated as a bonafide forecast for what to expect during the winter months across the United States.

But before taking these to heart, shouldn’t we first look back and see how they performed last year?

One quick note to start. There is not one but two Farmer’s Almanacs. The “Old Farmer’s Almanac” was started in 1792 while the “Farmer’s Almanac” began publishing in 1818. To be fair, we’ll analyze both against what happened during the 2017-2018 winter.

Let’s begin by looking at both Almanacs for the 2017-2018 winter compared to the actual temperatures recorded between November 2017 and March 2018.

The Old Farmer’s Almanac (top image) is harder to verify since it doesn’t break apart the country very well. They were incorrect across much of the West where they predicted cool temperatures, while most locations were warmer than average.

The Farmer’s Almanac (bottom image) is easier to verify since it breaks apart the US into simple regions. They hit the temperatures correctly in spots across the middle of the country but missed the warmer than average temperatures in the Pacific Northwest and Southeast.

Up next are the forecasts from both Almanacs for precipitation (snow) between November 2017 and March 2018.

Both Almanacs were wrong about California, Utah, and Colorado as it was dry compared to forecasts of “snowy” and “moderate snowfall”. Both Almanacs did a pretty good job of predicting a “snowy” winter in the Northern Rockies and parts of the Northeast but overall, the forecasts do not inspire confidence.

What does all of this mean?

Since there’s no track record of accuracy from the forecasts produced by the Farmer’s Almanac and the Old Farmer’s Almanac, we continue to have zero confidence in their forecasts for the upcoming winter season.

As we’ll continue to mention here on OpenSnow, long-range forecasts are rarely accurate. These forecasts cover multiple months but we know that skiing quality improves and degrades with storm cycles that last a few days to a week. Paying attention to a 1-10 day forecast will give you the best information.

Watch wildfire smoke blanket most of the country in this time lapse of satellite data ~ The Washington Post

Reporter

It has been an exceptionally smoky summer in the United States, as wildfires burning in the western United States and Canada have sent plumes of smoke over much of the continent.

For a sense of just how smoky it is, consider these two satellite-derived images of smoke cover, produced by the National Oceanic and Atmospheric Administration (NOAA). First, here’s the fire and smoke situation across North America as of March 21 this year. The red dots are the locations of wildfires, while the grayish splotches show the smoke they produce.


NOAA Hazard Mapping System Fire and Smoke, March 21. (National Oceanic and Atmospheric Administration)

There was fire activity in the Plains around this time but nothing too serious. The smoke from these fires was primarily a local issue, with little drift across large distances.

Compare the image above with the one below, which shows the fire and smoke situation this past Saturday.


NOAA Hazard Mapping System Fire and Smoke, Aug. 18. (National Oceanic and Atmospheric Administratio)

In this image, much of the continent is blanketed in a thick layer of smoke from massive fires in British Columbia, California and Ontario. The plume triggered air quality warnings from western Canada to the American Midwest, and created hazy skies as far east as Maine.

NOAA generates new images daily, so I’ve compiled the past 100 or so into a GIF going back to the beginning of May. It shows the ebb and flow of atmosphere smoke as North American wildfires ignite and die out. You can see the amount of smoke increase dramatically in the past few weeks.


Atmospheric smoke from May through August, via NOAA’s Hazard Mapping System. (NOAA/Washington Post)

The agency cautions that there’s room for error in its measurements. Its analysts’ “ability to detect fires and smoke can be compromised by many factors, including cloud cover, tree canopy, terrain, the size of the fire or smoke plume, the time of the day, etc.”

Public health experts treat wildfire smoke as a pollutant, similar in many ways to ozone or automobile emissions. Breathing it can be hazardous to your health, particularly for sensitive groups like children, the elderly and those with lung or heart disease.

Research has shown that even low levels of outdoor air pollution can cause notable deficits in cognitive performance and worker productivity. A 2014 study found that small particle pollution concentrations of just 20 micrograms per cubic meter — well below Environmental Protection Agency guidelines for 24-hour exposure — caused significant drops in the productivity of indoor agricultural workers, resulting in reduced pay for the workers affected.

Atmospheric smoke can cause air pollutant levels to surge well beyond those numbers. In parts of Idaho, for instance, current small particle pollutant concentrations are coming in at more than 100 micrograms per cubic meter.

So far 2018′s wildfire season has been a busy one, with a total year-to-date acreage burned well above the 10-year average. If that trend continues, expect more smoky skies heading into fall.

Shortages Loom For Lake Mead ~ CPR

Low level: Water intake pipes that were once underwater sit above the water line along Lake Mead near Boulder City, Nev., May 15, 2015.

John Locher/AP

A vital reservoir on the Colorado River will be able to meet the demands of Mexico and the U.S. Southwest for the next 13 months, but a looming shortage could trigger cutbacks as soon as the end of 2019, officials said Wednesday.A forecast from the U.S. Bureau of Reclamation echoes previous warnings that a nearly 20-year trend toward a drier regional climate coupled with rising demand could drain so much water from the Lake Mead reservoir that cutbacks would be mandatory.

The report increases the pressure on seven U.S. states that rely on the river to finish a long-delayed contingency plan for a shortage.

“If these projections materialize, we’re very quickly going to lose control of how to manage the deteriorating conditions on the Colorado River,” said John Entsminger, general manager of the Southern Nevada Water Authority, which serves 2.1 million people, including the city of Las Vegas.

The Colorado River system — including the giant Lake Mead and Lake Powell reservoirs — serves about 40 million people and 6,300 square miles of farmland. Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming rely on the river, along with native American reservations and northwestern Mexico.

The water is divided under international treaties, court rulings and interstate agreements. If there’s not enough water to go around, Mexico, Arizona and Nevada would be the first to see their shares reduced.

The Bureau of Reclamation forecast says all the users will get their usual share through September 2019. But the report projects that by October 2019, the surface of Lake Mead could fall below 1,075 feet above sea level, the agreed-upon point that would trigger an announcement of cutbacks that would occur sometime in the following 12 months.

The bureau operates on a water year that runs from October through September, tied to the cycle of winter snow and spring runoff.

“If everything holds true and the hydrology matches the models, then that’s probably where we’re going to be,” agency spokesman Marlon Duke said.

The chances of a shortage in late 2019 remain at 52 percent, the same odds the bureau announced in May, he said. Lake Mead has never had a shortage and if next winter provides enough snow in the mountains that feed the river, it could be averted, Duke said.

“It really depends on what kind of snowpack and precipitation we get across the basin throughout the coming winter,” he said.

The Colorado River states agreed to come up with contingency plans to conserve water and avoid mandatory cutbacks in the event of a shortage. But negotiations have been slow and difficult, in part because Arizona’s largest river users are still trying to agree on a unified state position, water experts said.

“Right now the thing that’s holding it up is Arizona and the inability to come together,” said John Fleck, director of the University of New Mexico’s Water Resources Program. “The whole system is at risk.”

A spokeswoman for the Central Arizona Project, the state’s largest water supplier, declined to comment. Officials of the Arizona Department of Water Resources did not immediately respond to an email seeking comment.

The Bureau of Reclamation dates the Colorado River region’s drought to 2000, but a small group of academics called the Colorado River Research Group said the river might be experiencing a longer-term shift to a more arid climate.

“Perhaps the best available term is aridification, which describes a period of transition to an increasingly water scarce environment,” the group said in a March paper.

The bureau report underscores the underlying problem that Southwestern states face, said Jennifer Pitt, director of the Audubon Society’s Colorado River Program.

The demand exceeds the supply, she said. “Anyone who has managed a bank account for families knows that over time, that spells disaster.”

El Nino – what it means for snow during winter 2018-2019 ~ Open Snow

 

The hype surrounding an El Niño winter continues to grow.

The forecast released in early August 2018 from the United States’ Climate Prediction Center’s (CPC) shows a 70% chance of El Niño conditions during the 2018-2019 winter season.

Why do we care about El Nino?

Ocean water temperatures across the world influence the tracks of winter storms.

One area of ocean water temperature that has the biggest impact on winter storms in North America is the central Pacific Ocean. This is the location of El Nino and La Nina.

Thanks to decades of research, scientists now have a decent ability to predict the strength El Nino and La Nina months in advance.

This means that even now in late summer, we are looking ahead to the temperature of the ocean during the upcoming winter, and it’s these water temperatures that can influence the tracks of our winter storms.

What and where is El Nino?

The water temperature in the central Pacific Ocean flips back and forth between warmer than average and cooler than average.

La Nina means that water temperatures are cooler than average.

El Niño means that water temperatures are warmer than average.

El Niño was originally recognized by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean.

The name El Niño, or ‘Christ child’, was chosen because these warm-water events happened to around the Christmas holiday.

The images below (courtesy of NOAA) show ocean water temperature compared to average in the Pacific Ocean. The top image is La Niña, showing cooler than average water temperature. The bottom image is El Niño, showing warmer than average water temperature.

What does all of this mean for snow during 2018-2019?

The water temperature forecast is for a 70% chance of a weak or moderate El Nino.

To forecast snow for the upcoming winter, we can look back on previous winter seasons with weak or moderate El Ninos to see snowfall patterns. The past can be a useful guide to the future, but it is NOT a perfect predictor of where the snow will fall.

Precipitation during a WEAK El Nino

The map below shows the precipitation during the winter (October – April) during 10 previous weak El Nino seasons. Green is above average, white is near average, and orange is below average.

Verdict: A weak El Nino often brings below average precipitation for most of the western United States. More favorable conditions (average precipitation and cooler temperatures) could come to the eastern mountains of Montana and Colorado, the southwest, and the northeast.

Precipitation during a MODERATE El Nino

The map below shows the precipitation during the winter (October – April) during 7 previous moderate El Nino seasons. Green is above average, white is near average, and orange is below average.

Verdict: A moderate El Nino is better (more snow) than a weak El Nino for most of the United States. Many areas of the west have seen average to above average precipitation during moderate El Ninos while the Northeast is mixed with more precipitation closer to the coast.

This winter’s forecast – weak to moderate El Nino

The zero line in the graphic below indicates average water temperatures. Above that line would be warmer than average water temperatures.

The squiggly lines on the right side of the graph all show a forecast for above-average water temperatures heading into this winter.

If we can get to 0.5 degrees C above average, that would be a weak El Nino.

If we can get to 1.0 degrees C above average, that would be a moderate El Nino.

The average of all the squiggly lines is about 1.0 degree C above average water temperatures, so right on the border between a weak and moderate El Nino.

You saw above that a moderate El Nino has (historically) delivered more snow than a weak El Nino, so let’s hope for those water temperatures to be on the high side of the forecast.

Final thoughts

There is a lot of hype about El Nino.

Odds of an El Nino for this winter are high (70%), but that’s not a guarantee.

If we do get a weak to moderate El Nino, remember that this can actually mean below average or average snow conditions for many areas of the United States.

In the next few months, you’ll come across numerous winter forecasts. These 1-6 month forecasts are rarely accurate.

If you need to plan your ski trip months in advance, feel free to look at long-range forecasts for snowfall, but focus on factors that you can control, like exploring new terrain and activities, ease of travel, and being with friends and family.

If your main goal is to enjoy deep, fresh powder, you’ll need to watch the forecast closely through the season. Forecasts out to 7-14 days can guide you to areas where the weather is trending cold and snowy, and then you can nail down the exact day and location of the best snow about 1-3 days in advance.

To see all the data you need to enjoy deep powder days, including detailed 1-10 day forecasts, consider upgrading to OpenSnow All-Access.

read BA’s analysis.