Friday, February 6, 2015

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.







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