Wicked Fast Jet Stream Over Pacific Contributing To Our Changeable Weather

Jet stream forecaast for the Pacific Ocean between Asia and
North America for this coming Saturday The fast flow (in pink and orange)
denotes a fast west to east flow that is influencing the weather
across the United States, pushing repeated storms
into the West Coast, which turn into fast moving
disturbances racing generally west to east across the
United States. 

Lately, there's been a hugely fast west-to-east jet stream over the Pacific Ocean from Asia all the way to the North American west coast, and that's been influencing our weather here in Vermont.

This state of affairs began before Christmas and will continue at least into the middle of this month, if not beyond.

I'll get into how this affects Vermont in a bit. -

This jet stream has been sending a series of fast-moving storms into the West Coast from central California north into British Columbia, Canada.

These storms have been, and will continue to dump bursts of heavy rain and blinding mountain snow in these region

These have also brought damaging winds to California, Oregon, Washington and especially British Columbia over the past couple of weeks. Just over the weekend, Seattle had a gust to 60 mph, it's highest gust in 12 years. About 300,000 people were without power because of the storm.

The good news with this pattern is rain has been falling off and on through most of California, and a decent snowpack is building up in the Sierra Nevada Mountains.  That's great for the parched state's water supply.

Of course, a lot of those occasionally heavy rains are falling on massive areas scarred by last year's wildfires. Mudslides in one of these burn areas over the weekend closed the Pacific Coast Highway near Malibu. This is an area that was hit by a large wildfire late last year.

Several motorists, including rapper Soulja Boy, were trapped in the mud and debris on that highway. Everyone was rescued, nobody was hurt, but many of the cars were badly damaged or destroyed.

A couple video clips of the rough West Coast weather are at the bottom of this post.

THE OVERALL PATTERN

These storms have been zipping eastward across the United States, seemingly just on momentum alone. Most of the moisture from these storms get stripped off by the mountains in the West, so they become somewhat moisture-starved.

Some, but not all of the storms manage to pick up replacement moisture from the Gulf of Mexico, which helps explain why the Southeast has been so wet lately.

All this energy from had been those strong storms on the West Coast is still mixed up with all this. Pressure gradients between the storms and brief high pressure systems have caused frequent bouts of windy weather coast to coast, including here in New England and Vermont.

I noticed winds gusted to 40 mph in Burlington Sunday. The next system Tuesday morning will bring gusts of 45 mph to the Champlain Valley. More gusty winds are in the forecast for Thursday.

This seemingly endless parade of storms running east to west across the nation have been blocking any long-lasting cold waves from invading the country. Behind each storm, a bit of Arctic air does get stripped off and sucked southward from Canada, giving brief cold snaps to the northern tier of states, especially here in New England.

Notice that temperatures were in the single digits either side of zero here in Vermont this morning with subzero wind chills.

Then the next storm comes along, scooping a bit of mild air up from the south to give us a quick warm spell. Then the cycle repeats, over and over again. This is why the weather has been so changeable here in Vermont since Christmas: Warm to cold back to warm again.

The relatively flat east to west jet stream means most of the storms don't get a chance to become super strong. The last really substantial storm we had was on December 21 and 22, which caused flooding across Vermont. We've had six quickie storms since then, all of them pretty minor.

It's January, so it's not too hard for some pretty cold air to briefly bleed in between storms.

BOTTOM LINE FORECAST IN VERMONT

The first round of snow this week, late tonight and Tuesday
morning, will only amount to an inch or two for most
of us, with possibly even less than that in the Champlain Valley.

Here's how the next few days look The next one coming along tonight and Tuesday morning will bring some more relatively light snow, with patchy valley rain.

The strong winds, those 45 mph gusts in the Champlain Valley and 35 mph gusts elsewhere in Vermont, will peak late tonight and during the early and mid-morning hours on Tuesday.

Total snow accumulations with this initial burst will be one to three inches, with locally less than that in parts of the Champlain Valley.

There will be a lull in the action Tuesday afternoon and evening. No cold air will be able to sneak in during this time, so it will remain mild, with highs in the 30s to near 40 Tuesday and temperatures staying in the low 30s for most of us Tuesday night.

Another disturbance in this quick jet stream flow will come in late Tuesday and Wednesday. This one looks like it might be good enough to dump several inches of snow, perhaps two to six inches of powder, by Wednesday afternoon in much of Vermont.

The Champlain Valley might miss out again: It will be mild, so there, some of the precipitation, especially earlier on Wednesday might come down as a cold rain, which would minimize accumulations.

Overall, these frequent snows are great for winter sports prospects this month in the Green and White Mountains, and the Adirondacks.

After this relatively snowy period, the door will open for a piece of an Arctic high pressure system will break off and head south into New England, giving us the strongest, or nearly the strongest cold snap we've had all winter. This will hit next weekend, but don't worry too much about it.

Snow showers, mostly in the mountains, will continue amid the strong northwest wind gusts and falling temperatures Thursday, introducing a good three-day long cold snap.

It will be a run of the mill January cold snap, nothing we haven't seen before. We'll gethighs in the single numbers to near 10 and lows mostly in the 5 to 15 below range over the upcoming weekend. However, the west-to east race of storms will continue, though, so the cold snap won't last long.

It's possible, but not definite, that the next weather disturbance that originated in the Pacific Ocean could create a coastal storm that could dump some snow on us toward next Monday. That is highly uncertain but something to watch. One computer model gives us a substantial snowstorm, most of the others forecast not much of a storm and little or no snow for the region. We'll see.

Beyond that, the fast air flow across the nation will probably continue and our changeable, back and forth Vermont January weather will continue as it has since the start of the month.

Here are some of those weather video clips from the stormy West Coast.

First, a news clip about the mud slide along the Pacific Coast Highway:



Here's some footage of wind storm damage in Washington State from Saturday night and early Sunday morning:

West Coast Is Where Weather Action Is At, But Things Will Get Active Here, Eventually

Northern California fires are now largely contained, but
weather conditions could prompt new wildfires over the
next few days, especially in southern California.

Most of the weather action over the next couple of days will take place out west, especially along the West Coast, as we Vermonters bask in the very warm, sprawling high pressure system that's stuck over us and much of the rest of the East.

Here, temperatures will be way, way above normal all weekend with wall to wall sunshine, so perfect if you want to get outside to check out the lingering foliage, or just get yard work done.

But expect bad weather for that kind of thing on parts of the West Coast.

In Washington State, a very strong, wet storm is moving in this weekend. Enough rain could come with it to touch off some flash flooding. That's especially true in areas that had forest fires this summer. The trees and plants and such that held soil in place burned away, so the heavy rain get wash away dirt and fire debris and anything else. This could be dangerous.

It had been hoped that some of this rain would sneak down into the San Francisco Bay area and the Napa and Sonoma areas of California, since this is where those big, deadly wild fires were earlier this month. Some of those fires are still burning, and it would have been nice if a little of the rain from the Washington storm would move south.

Unfortunately, it's not to be. All the rain looks like it's going to stay north of this burn area. On the bright side, it did rain a little in this region Thursday, with Napa, California picking up 0.19 inches of rain. Not much, but a help. On the dark side, it looks like it's going to turn hotter and windier and drier in northern California next week.

Meanwhile, there's a strong risk of new wildfires erupting in southern California today through Tuesday. A Santa Ana event is taking shape, which would bring strong winds from the deserts, high, near record heat and very low humidity to much of southern California.

Fire warnings and excessive heat watches are in effect for much of southern California, as you's expect.

The other hotspot in the weather today is the southern and central Plains, especially around Oklahoma, where tornadoes and severe thunderstorms could erupt today.

Eventually, some of this activity out west will consolidate and set up some storminess in the eastern United States by midweek. The rain will affect Vermont, which is great since it's been so dry. We're not yet sure how much rain will come down, but we'll take anything we can get.

I had originally thought we'd get a winter preview by the end of the upcoming week. It will cool down by then, but only down to slightly warmer than normal conditions, compared to the much  warmer than average weather we're having this weekend.

"Fire Hose" Aimed At Northern California

A representative map of an atmospheric rier.
That orange band coming across the Pacific Ocean
to the West Coast is a narrow band of intense moisture
that would produce, in the example given here,
torrential rain and flooding to central California.

Get ready people in northern California and parts of coastal Oregon.

The Pacific Ocean fire hose is ready to soak you down but good.  Expect inches upon inches of rain over the next few days.

Sometimes in the winter, a fairly narrow zone of fast moving storms aims at the West Coast. It looks like northern California and Oregon are in for it over the next week.

Some of the computer models are forecasting over a foot of rain over the next seven days. Some areas are likely to get two to six inches of rain just on Sunday in northern California.

I'm calling it a fire hose, as the weather pattern is basically a narrow, intense stream of deep moisture hittng parts of the West Coast. Meteorologists, though, call this an "Atmospheric River."

And that's pretty much what it is, a river. Except it's a narrow band of deep moisture in the atmosphere, not a literal river. Still, the amount of moisture transported in an atmospheric river hitting the West Coast can be ten times the flow of liquid water in the Mississippi River as it it approaches the Gulf Coast.

These atmospheric rivers hit the West Coast most winters. They're more likely when there's an El Nino, and of course we've got a strong one under way now. Which means I'm totally not surprised there is one expected in the next few days.

Atmospheric Rivers can come in various intensities, of course. They are sometimes good, as they are on average respondible for a third to a half of the needed winter precipitation along the West Coast.

They are sometimes bad, as you can imagine, because they can easily bring flooding and mudslides to  the West Coast.

The atmospheric river about to hit northern California and Oregon seems to be moderately intense, and is both good and bad.

Good, because it's putting another substantial dent in the California drought, especially for the northern half of the state.

Bad, because this one will put some rivers above flood stage and swamp urban streets whose storm drains can't handle the downpours.

Most dangerously, it can cause sudden and life threatening mudslides and debris flows, espeically in areas that had wildfires last year that stripped vegetation from the landscape. Note there were a LOT of wild fires in the region being hit by this atmospheric river, so, Not Good.

Though it's not going to happen this time, there is fear that one day, there will be a Super Atmospheric River that would overwhelm the levees protecting very flood prone Sacramento and surrounding areas.  If that ever happened, it could be a catastrophe on the scale of Hurricane Katrina in New Orleans.

Again, we're not expecting anything nearly that bad this time.

But you will see news and images of flooding and mudslides in the northern half of California and in Oregon over the next week.

Atmospheric rivers don't continue on across the United States. The mountains in the West tend to break them up. But the remnants of these almost always stir up new storm systems that cross the country eventually.

One such atmospheric river-spawned storm is likely to cross the southern United States next week, but that particular storm at this point does not look like it will be particularly strong or dangerous.

Very Early Pacific Hurricanes Providiing Bit Of Southwest U.S. Drought Relief

Because of El Nino, the number of tropical storms and hurricanes along or off the United States East Coast is supposed to be lower than usual this year.

Hurricane Bianca off the west coast of
Mexico on Saturday.  

Not so in the eastern Pacific. Unusually warm El Nino waters have already produced two strong hurricanes out there, which is unprecedented for so early in the season.  

Andrew spun out to sea into cooler waters and died last week. Bianca reached Catagory 4 status this weekend, and is now getting weaker as it moves into cooler waters. 

It should still hit Mexico's Baja Penninsula as a tropical storm. (Hurricanes thrive in warm water, and fall apart in cooler water)

It Baja California does get a tropical storm, it will be the earliest in the season on record that the region has had such a storm, says Dr. Jeff Masters. 

Moisture from these hurricanes won't end the drought in southern California and parts of Arizona, but the storms are providing a bit of unseasonable moisture to the region.

For instance, Phoenix, Arizona recorded 0.16 inches of rain Friday. That's a drop in the bucket, but it's extremely unusual for rain to fall in Phoenix in June.

It's too late in the year for cold fronts to press as far south as Phoenix, so no rain from those. Later in the summer, the desert heat lowers the air pressure in the Desert Southwest, bringing in moisture from the Gulf of Mexico and thunderstorms. But that never happens until July or August. June is usually dry, dry dry. 

Moisture from Bianca is going to draw even more unusual moisture into southern California and Arizona, so look for more welcome rain in that region. Just not enough to come close to easing teh drought.

And if there's lightning, that could set off forest fires, so as you see, this weird hurricane rich weather pattern out there isn't going to be all good.

Another problem: Some of this tropical moisture could find its way into parts of flood ravaged Oklahoma and Texas. They surely don't need any rain at the moment, so this could be troublesome.

Some of the moisture from the hurricanes could even interact with weather systems in the Midwest next week, making rain heavier and making local flash floods more likely. Though I'll emphasis most of the moisture for these storms will come from the Gulf of Mexico. 

A wide stripe of the nation from Oklahoma and South Dakota, across the Midwest to northern New England are expecting two or more inches of rain over the next week. 

Further north, from central California on up into Washington, near record heat is forecast for the next few days. (It had been blessedly cooler than normal in recent weeks in this region.) 

The dry heat this week will worsen the already terrible drought along the central and northern Pacific coasts of the United States. 

Odd U.S. Weather Weekend: NW Storms, Central Heat, New England Snow (AGAIN!)

Forecasted precipitation for the next seven days.
Click on the map to make it bigger and easier
to read. Up to 17 inches of rain is forecast
for parts of the West Coast. In New
England, the map shows anywhere from 0.75 to more than
two inches of melted precipitation. That translates
roughly to 6 to 18 inches of snow  

The next few days are going to be kinds of weird, kind of extreme in many parts of the United States this weekend as we continue to grip with a weather pattern that is bringing persistent, and unusual conditions to many areas.

Let's start with the West Coast, from central California north to Washington and on into British Columbia, Canada.

WEST COAST

California, in particular, needs rain after what was one of the driest Januaries on record, which worsened the ongoing drought.

The good news: Much of California is going to get a bunch of rain over the next few days. The bad news: It's coming too much, too fast.

Pretty big sections of northern California, Oregon and Washington are going to get more than six inches of rain. Some will get a foot of rain. A few pockets of California could close in on 18 inches of rain within the next week.

Now, 12 to 18 inches of rain in California would be a godsend if it were spread out over a month or two. Over the course of a week? Not so much.

This storminess is an example of what is known as the Pineapple Express. The jet stream organizes moisture from the areas around Hawaii, and directs it in a relatively narrow stream toward the West Coast. In this case, it's roughly between San Francisco and Seattle.

Picture a giant firehose aimed at this region and you get a good idea of what the Pineapple Express is.

Also, this is a warm storm pattern. You want snows to accumulate up in the Sierra Nevada Mountains so it would gradually melt and supply water in the spring and summer.

But snow levels with most of these storms is going to be at a high elevation, so there's not going to be as much new snow in the mountains as people would like.

Despite the drought, there's going to be some flooding out of this in California. Flood watches are up for much of northern California.

Up toward Oregon and especially Washington, it's been a little wetter this winter than points more to the south. Flood watches are of course in effect in that region, and some rivers are already above flood stage due to off and on heavy rain that started Wednesday.

There's also the risk of landslides, especially in Washington, with this heavy rain through the weekend. This is a very similar danger to the flood and landslide disaster in early January, when flooding damaged a lot of property and landslides knocked homes off their foundations, especially around Hoquiam, Washington. 

Wind is going to be a problem with this West Coast storminess, too. High wind warnings are up for big stretches of California on up north. Each of three strong storms flowing along the Pineapple Express will bring three separate bouts of strong winds today, Saturday and Sunday.

The biggest threat of the most damaging winds looks to be coming Sunday, when the strongest of the storms comes ashore.

"This is a classic pattern for a damaging wind storm at the coast," said the National Weather Service in Medford, Oregon, referring to Sunday's expected storm.

It looks like southern California is going to get little, if any rain out of this system, so the drought continues there. And for all of California, that persistent ridge that's been shunting most storms, until now anyway, away from the coast, will be back

CENTRAL U.S. HEAT

In parts of the Rocky Mountains and the Plains states, the story is springlike weather. What winter?

Salt Lake City Utah reached a record high for the date of 64 degrees Thursday, and could match its all time record high for February of 69 degrees, says the Weather Channel.

Denver is expected near record highs of around 70 degrees today, with similar readings on Saturday.

Amarillo, Texas, which suffered through a rare foot of snow back on January 21, is having a nice recovery. A record high of 80 degrees is expected Saturday.

After experiencing three days in a row with highs in the record territory of upper 70s in late January, Oklahoma City is expecting perhaps four days in a row with temperatures reaching or exceeding 70 degrees, starting tomorrow.

Of course, with all the sunshine and warmth and low humidity, fires are a concern in the southern Plains over the next few days. There were some nasty fires during the late January winter heat wave, so you know the danger is real.

A ridge in the upper levels of the atmosphere, propped up in part by that Pineapple Express out west, is contributing to the nice taste of spring out in the West.

NEW ENGLAND

It's not exactly springlike in New England, that's for sure. Oh, New England, what are we going to do with you?

After suffering repeated bouts of heavy snow and bitter cold the past two or three weeks, the region is in for - wait for it - repeated bouts of heavy snow and bitter cold.

Things got off to a rough start this morning, with temperatures as low as the 30s below zero in northern Maine, lots of teens and 20s below zero in the rest of northern New England, and some record lows in southern New England.

This unhappy camper in Massachusetts
is going to get even more unhappy, based
on forecasts for the next few days.  

Bradley Airport, near Hartford, Connecticut had a record low of minus 7 this morning, for instance.

More of the same is coming. I guess it will sort of warm up for awhile this weekend, but that's a relative term. High temperatures will be in the teens and 20s.

Even worse for snow-weary New England, it's going to snow again. In some places, a lot.

This is a weird weather set up. An arctic cold front is coming to a stall in the Mid-Atlantic states. To the north, it's bitter, to the south of the front, it's nice and warm. Warm air trying to work north will go up and over the cold air.

This rising air with that warm-ish air rising over the frigid air will touch off periods of light snow in New England, northern New York and parts of the upper Midwest.

Little storms will ripple roughly west to east along the front, helping with the snow. The strongest of these disturbances will come along late Sunday into Monday. That'll eventually spin up a storm along the coast, which will eventually go out to sea.

It probably won't snow super hard in New England during this snowy period. But it's going to last a long time. So snow will gradually keep piling up and piling up. Not needed in places that have had several feet of snow in recent weeks.

It's always hard to tell where the deepest accumulations will hit, especially with weird, complicated weather patterns like this.

Things could change, but overnight, the weather forecasting models shifted the deepest accumulations northward a bit. If that sounds familiar, it's because that's been the pattern with the forecasts. At first it seems like things will go off to the south, but then the stormy weather shifts northward.

Anyway, and I caution this is just a preliminary guess and everything could still change, it looks as if the deepest snow might accumulate across the New York Adirondacks, central and southern Vermont, the southern half of New Hampshire and the northern reaches of Massachusetts, north of the Mass Pike.

In these areas, up to 18 inches of new snow could pile up between Saturday and Tuesday. This is particularly bad news for the suburbs north and west of Boston, and southern New Hampshire, which have received the brunt of the heavy snow over the past three weeks.

Even in northern Vermont and northern New Hampshire, there is the chance of six to 12 inches of snow, maybe even a little more, with this long snowy spell.

After that, guess what? Another blast of frigid Arctic air. This one, especially as we get toward the end of next week, could be the coldest yet this winter.

This pattern shows no sign of breaking into early March. If that forecast holds expect more frigid weather and frequent bouts of snow through the month.

As it looks now, there's a very chance that cities throughout New England could end up with one of the Top 5 snowiest Februaries on record, or one of the Top 5 coldest Februaries on record, or BOTH.