Thursday, February 22, 2018

Why Very Nice Weather Is Scary

My St. Albans,  Vermont yard Tuesday as the thaw
really took hold. 
If you're outdoors and it's partly sunny and 77 degrees, you should not be scared of the weather. After all, such weather sounds pretty pleasant.  

If you were in Bennington, Vermont yesterday, February 21, you experienced just that kind of weather. Note I said Vermont. In February. You can see why such weather in this case can be a little unnerving.

The weather extremes keep getting more extreme. A few years ago, I would have said it's pretty much impossible to get to 70 degrees in Vermont in February.

Then, yesterday, it was in the upper 70s. And we've now had two Februaries in a row in which it has been in the 70s in Vermont. The winter before that, it was 70 degrees in Vermont on Christmas Eve.

I keep telling you that a weather event on one dot on the map like Vermont does not tell you much about climate change. That is still true.

Yet, the entire East Coast was baking yesterday.

No fewer than 21 cities in the eastern United States from Florida to Maine broke records Wednesday for their hottest temperature on record for any February date.  Wells, Maine; Manchester, New Hampshire and Bennington, Vermont all hit 77 setting February statewide records across northern New England.

Tampa, Florida also hit an all time February record high of 89 degrees this week.

Same spot as above, 24 hours later. 
The weather extremes here in the Green Mountain State seem like they're getting more extreme and more frequent. That wouldn't be that big a deal except the extremes are getting more and more wild across many if not most parts of the world.

Of course, the trouble is, how do you measure the frequency of extremes. The overall temperature of the Earth is rising. That's relatively easy to measure. (NOAA just said that January for the Earth as a whole was the fifth warmest on record. And that means the Top 5 warmest Januaries have all occured since 2007.)  

Climate scientists tell us global warming will cause greater weather extremes. Anecdotally, that's easy to see. In addition to Vermont's February roast, a persistent stalled fetch of deep moisture is once again drowning parts of the Gulf states and South in flooding. The temperature is about to go above freezing at the North Pole like it's done a few times in the winter in recent years, which is very odd.

Arctic ice extent is at record lows for this time of year, and a bitter cold wave is heading toward western Europe from Siberia.

One way to look at the frequency of extreme weather is by examining warm spells, like the kind we just experienced yesterday.

Back in 2014, before many of the latest big, big heatwaves, Real Climate said record hot months at stations around the world were outpacing record cold months by a five-to-one margin. You can infer from this the world is warming as an unchanging climate would produce roughly equal numbers of hot and cold months.

An incredible  36-month streak of daily record maximum records exceeding daily record low minimums at weather stations throughout the United States ended in January, where record lows slightly outpaced record highs.

We're back to our old tricks, though. So far this month, U.S. weather stations have seen 1,707 daily record high temperatures versus just 174 record lows. Also so far this February, 37 weather stations have recorded their all time highest temperature for the month of February while just one recorded an all-time record low.

Another way to look at extreme weather events and trends in those events is the growing field of attribution science.

As Annie Sneed explained in Scientific American last year, computer programs are getting better at simulating the cause of extreme weather events, then estimating what would have happened without climate change. I'd better let her explain it:

"In our experimental set-up, we simulate the event in today's world, and then we remove anthropogenic emissions from the climate model's atmosphere, and do the same experiment again.  ...... Assuming everything else being equal, what is the influence of greenhouse gas emissions?"

This is all great, of course, but still, is there a way to measure the number of extreme events, say 100 years ago, compared to now?

I haven't come across such statistics, but I wish they existed.

Every time something extreme happens in the weather, climate change denialists and skeptics will point to a similar extreme in the past.

Yes, wild weather has always happened and always will, with or without climate change. Yes, it was in the 70s in New England yesterday, but it was 120 in the Great Plains in the summer of 1936.

However, are big hot spells more frequent than they were early in the 20th Century? The denialists and skeptics won't answer that question.

Muddying things further, some extremes that happen are just bad luck and have nothing to do with climate change. Or they would have happened anyway, but were possibly or probably made worse by climate change? How do you measure and prove that?

The consensus among scientists is that weird weather, like yesterday's summery February East Coast heat wave, is becoming more frequent with climate change.

The February heat wave wasn't as harmful as some big extremes, though budding flowers and crops up and down the East Coast will probably fall victim to normal spring freezes. In the past, if it got cold in March, who cares because plants hadn't started blooming yet.

Now we're getting these weird hot spells. California had a record warm winter, forcing crops and trees to start blooming too early. Then the inevitable winter frost and freeze hit last week.  The states $5 billion almond industry was almost certainly damaged by this.

Last year also had record February heat along the East Coast. Cherry blossoms in Washington DC bloomed too early, then many of the blooms were zapped and killed by a March freeze. Those blossoms are starting to bloom again this year, way too early. Will the same thing happen again.

As nice as this week's incredible February warmth felt to many of us, any weather extreme is bad, as I've just outlined.  And if extremes are getting wilder and more frequent, there's lots of trouble ahead.

Which is why I was scared yesterday when it was a very pleasant 77 degrees in Bennington, Vermont yesterday. In February.  Even as, exactly 24 hours later, Bennington was right back to normal February conditions: 30 degrees with fairly heavy snow falling.




Wednesday, February 21, 2018

Incredible February Heat Records In Vermont, Northeast And Arctic Beyond Unprecedented

This was a snow covered scene in my St Albans Vermont
yard two days ago. Today, amid record heat, I felt like I
should have been planting flowers. 
This is just a quick Wednesday evening update, as I will have more to say about this tomorrow, but some temperatures were recorded today in Vermont and elsewhere are just beyond belief.

A bit of history: Last February, Burlington and Bennington, Vermont reached 72 degrees, breaking by a large margin the record for the hottest temperature ever recorded in the Green Mountain State during the second month of the year.

At the time this happened, I remember saying that even in the worst case scenario for global warming or whatever is going on, chances are we wouldn't see something like that in our lifetimes.

Boy was I wrong!!! Bennington, Vermont reached an amazing 77 degrees today, five degrees above last year's record and so warm it's scary.  I mean, really scary. That's a typical summertime high temperature. In February!

A cold front arrived in Burlington today before maximum temperatures could reach their highest potential. Still, it got up to 69 degrees in Burlington. Had last year not set the February record, Burlington would have exceeded the previous record high for February, which until 2017 had been 62 degrees.

Also today, Montpelier reached 70 degrees, by far their hottest February reading on record. Elsewhere, New York City's Central Park got up to 78 degrees, its hottest February temperature on record.

While all this was going on, extreme weather was causing all kinds of issues elsewhere in the nation. Record lows are being reported in the northwestern third of the United States, but those lows, while very unusual, can't compete with the bizarre warmth it the Northeast.

An airmass with a record high amount of moisture for this time of year today unleashed flooding downpours in Louisiana and Arkansas. These are states that have had an increasing frequency of flooding in recent years and decades.

Also today, freezing rain was falling from Minnesota to Texas.

And up in the Arctic, temperatures are expected to rise above freezing around the North Pole by Sunday. That's something that used to never happen this time of year.

Arctic sea ice is actually decreasing in extent this week. The Arctic ice is already at a record low extent for this time of year. The ice should still be expanding this time of year. It's only February.

According to the Washington Post, temperatures in the Arctic are now as much as 45 degrees above normal. The northernmost weather station in Greenland was above freezing this week for a full 24 hours. This in a place where the sun set in October and won't rise above the horizon again until March. Yet, they've had a thaw.

I'm not a scientist, but these developments are all very unnerving.

I  MUST give you the caveat that an individual weather event isn't proof of global warming. But the extremes today are consistent with global warming. Also, in terms of extremes, today's weather is also beyond the worst fear of many climate scientists.

I'm sure things will settle down once the current wild weather pattern settles down, but today's weather news frightened me more than almost anything I've seen in my more than five decades on this Earth.

Tropical Vermont In February Continues For (Part Of) Today

Here's something I thought I'd never see. A forecast
map issued by the National Weather Service office in
South Burlington, Vermont forecasting high
temperatures today - in mid- February - in the
low 70s across western Vermont. 
Just a quick update this morning as I've got an early meeting.  

That strange February heat wave has arrived and records are already falling. It was more than a little bizarre this morning to take the dogs outside this morning in far northern Vermont comfortably wearing shorts and a t-shirt. In Vermont! In February!

Before midnight, Burlington, Vermont had a record high for the date of 59 degrees.

Before dawn this morning, it was already 61 degrees in Burlington, a record high for today, and the temperature will keep rising before a cold front comes in this afternoon.

It's actually too bad the front is coming when it is. Had it held off until evening, the temperatures would really climb. Still, this heat wave is unprecedented, in an era when we're having unprecedented heat waves now once every few months or more. (Examples: Remember the four days of 90 degree heat in late September, during the autumn? and the 70 degree heat at the end of February last year?)

By the way 61 degrees at 5 a.m. in Burlington is exactly normal for that time of day in mid-July, the peak of summer. Today's forecast highs, in the 60s, with a few low 70s possible in southwestern Vermont, are normal for late May.

If it reaches 70 degrees in Vermont today, this will be the third winter in a row that the Green Mountain State has seen 70 degree readings during both the winter.  That's never happened before.

The flood watch is still in effect for today for most of Vermont and northern New York as the snow is rapidly melting, rivers are rising and ice jams are holding in place. As of dawn, I haven't seen many flood warnings in the region yet, but I have a feeling that will change soon. There was an ice jam on the Ausable River in New York that prompted flood warnings for awhile overnight.

The only good news regarding the flood watch is that although there will be showers around with the cold front this afternoon, those rains won't be particularly heavy and they won't last all that long in any particular spot.

After today, it's back to winter reality in Vermont with temperatures tonight bottoming out near 20 degrees by dawn and rising to only the low 30s Thursday afternoon. Which is normal for this time of year.

Beyond that, we're still in a weather pattern in which there's a strong ridge of warm high pressure to out southeast and cold air over the continent. That will drive a few  modest storm systems by us through the weekend.

It'll be warm enough so that most of the precipitation will be rain, but snow will mix in at times. There will be some light accumulations in the mountains, but not remotely enough to replace what was lost in this heat wave.

While we Vermonters are basking in summer warmth for at least part of today, freezing rain in the middle of the country extends as far south as central Texas.  

A conveyor belt of deep moisture and heavy rain that started a couple days ago continues to run from northeast Texas to the Great Lakes.

Flood warnings and watches continue to extend from Texas to Michigan. Some areas have had up to five inches of rain already. Another six or seven inches of rain or locally more is forecast over the next several days in and near Arkansas, so flooding will continue to spread and get worse.


Tuesday, February 20, 2018

This Vermont February Hot Spell Will Be Really Weird. Strange Weather Everywhere

Snow was rapidly melting in my St Albans, Vermont
yard this morning. I expect pretty much all of this snow
to be gone by tomorrow with record heat moving in
As of this Tuesday morning, a warm front was slowly working its way north into and through Vermont and the rest of New England, setting the stage for that long awaited record heat.

This is just part of the extreme weather pattern I referred to yesterday that will keep forecasters veyr busy, and likely guessing at what's next for days, if not weeks

As the warm air comes in, signs of the strangeness are there already. Typically, warm air will come in at higher elevations first as a winter warm front arrives. That's true this time, but up above us, it's really warm. Atop Mount Mansfield at 8 a.m., it was already 46 degrees.

Even loftier Mount Washington was 40 degrees as of 10 a.m. Their all time February record high up there is 43 degrees, so they have a good shot.

The warm air will continue to creep in, southwest to northeast all day. High temperatures for the day will probably occur toward evening.  It'l be warmest to the southwest, where parts of New York and low elevations in southwestern Vermont will get close to 60 degrees.

Flood watches continue across the region, for good reason. Part of the problem, of course, is the rain that's falling across our area with this warm front. The air is humid, and will get more humid. Dewpoints will rise into the 50s, which is typical for summer.  When it's this warm, especially when the air is humid, melts snow really, really fast.

Rivers will rise quickly by later tonight through Wednesday. The biggest problem areas, of course, are where there's existing ice jams, but I imagine rivers will go over their banks to cause at least minor flooding across some river valleys in Vermont.

At mid elevations, there was two to four inches of "rainfall" locked in the snowpack. That snowpack will have completely disappeared by Wednesday. So that's two to four inches of "rain" on top of the actual rain coming out of the sky during this hot spell.

Actual temperatures overnight will also be in the 50s, possibly near 60 in some of the warmer areas as we get close to dawn. Again, that's something that we often seen in the summer, but not February!

The February heat here in Vermont will be brief, but intense. It's usually very hard for computer models, and human weather forecasters to get a handle on exactly what will happen, since this kind of thing is so unprecedented.

At the moment, the National Weather Service in South Burlington, Vermont is going for a high temperature of 69 degrees in Burlington on Wednesday. If not for last year, that temperature would have broken the record for the hottest February day by seven degrees.

That is, except for last year, when the February temperature in the Queen City reached an incredible 72 degrees. So we'll probably end up with the second hottest February temperature on record.

But the top two hottest February days coming in consecutive years?!?!? Wild.

The NWS in South Burlington looked at the trajectory of the air that is supposed to be over us tomorrow. That is, where it's coming from. Their answer: Grand Bahama Island.

Also, if it hits 70 degrees anywhere in Vermont on Wednesday, it will be the third winter in a row where it was 70 degrees somewhere in the Green Mountain State.

Depending on the timing of an afternoon cold front on Wednesday, we definitely have a good shot of seeing a spot 70 degree reading in the southern Champlain Valley, the lowlands of southwestern Vermont, or in the Connecticut River valley down by Brattleboro.

As noted, a cold front will come in during Wednesday afternoon. There will probably be a very abrupt drop in temperature into the low 50s during that time - still awfully hot for February.

OFF THE RAILS ELSEWHERE

This weather pattern, as noted, is causing all sorts of issues across the nation - and elsewhere, really.

Repeated thunderstorms and downpours have much of Michigan awash in floodwaters. Other downpours - amounting to more than half a foot of rain in many areas, will stretch from northeast Texas to the Tennessee and Ohio river valleys over the next few days, so major flooding will be in the news from there.

On the cold side of this weather system, an ice storm is unfolding in parts of Kansas and Missouri. As of this morning, those areas were getting freezing rain, punctuated by claps of thunder at times.

In Minnesota, freezing rain was also coming down. And, as expected, a hard freeze was killing crops this morning in California's Central Valley.

LOOKING AHEAD

The weather pattern across the Northern Hemisphere is turning "blocky." That means that big gyrations in the jet stream are slowing down storms and weather systems and making them move in odd and unpredictable ways at times.

For us here in Vermont, that means a gradual cooldown over the next several days, with several chances of rain and snow. Readings will still be warmer than normal heading into this weekend, just not extreme like we're expecting tomorrow.

With this blocky pattern, we could have some interesting weather much of next week, but nobody really knows yet what we mean by "interesting." Storms? cold? warm? Stay tuned.

This impending pattern is flooding the Arctic with what for them is unseasonably hot air near the freezing point. And very cold, possibly near record cold will spread across Europe and into Great Britain.

Never a dull moment, huh?




Monday, February 19, 2018

This Could Be Vermont's Four Really Off The Rails Weather February In A Row

Day lillies bizarrely begin to sprout during all time
record February warmth last year. 
Forecasts for midweek in Vermont tell us  we'll be seeing temperatures in the 60s to around 70 by Wednesday in most of the state, which is really incredible for February. In fact, it would be unprecedented if not for last year.

If the forecast comes true, it'll make if the fourth February in a row that has rewritten, or at least altered, record books. One of those Februarys, 2015, was very cold. The other three are seeing record heat.

Let's get 2015 out of the way. It was a brutal February, the third coldest on record with a mean temperature of 7.6 degrees. That's nearly 14 degrees below normal. There were no extremely cold nights that month, nothing in the 20s to near 30 below zero.

But the cold was grindingly consistent. In Burlington, 17 of the 28 days that month had temperatures below zero.

Subsequent Februarys turn hot. The first week of February, 2016 saw record highs in the 50s. That week is normally the depth of winter, but I recall working in my garden, digging completely unfrozen ground as I prepared new perennial beds.  I'm so far north that I can literally see Canada from my house.  So that was a new experience.

February, 2016 ended up being the 9th warmest on record. It would have averaged even higher if not for a brief Valentine's weekend cold snap that brought temperatures into the teens below zero before readings quickly recovered.

February, 2016 brought heavy rains, too. Places like Hardwick and Springfield Vermont saw several buildings and businesses damaged by flooding. Rainfall in one storm that month amounted to as much as 2.8 inches in just over 24 hours. That's nearly double the amount of precipitation that usually falls in an entire February.

Garden work in far northern Vermont in umfrozen ground
early February 2016. At that time of year, the earth should
have been frozen rock hard with snow covering it, but
record heat changed that scenario. 
Then there was the piece de resistance, February, 2017, which really, really went off the rails. By the 23rd of the month, Burlington reached 63 degrees, breaking the old all-time record high for February of 62.

But we were just warming up. Literally. On the 25th, Burlington reached 72 degrees, shattering the monthly record. It was also 72 in Bennington during that hot spell, so both figures now stand as the warmest readings on record for anywhere in Vermont.

The warmth was so extreme that severe weather came all the way north into New England. It was so weird the first February tornado on record in Massachusetts damaged homes in the western part of the state.

Now we're waiting to see how weird this week gets. We'll keep an eye on it for sure!

Sunday, February 18, 2018

Extreme Weather Pattern Is About To Create Lots Of Extreme Weather

As of Sunday afternoon, the map on the home
page of the National Weather Service was lit up
with lots of colors. That signifies lots of weather
watches, warnings and alerts, meaning there will
be a lot to talk about in the weather over the coming days.
The dark green you see in Vermont is a flood watch.
The jet stream and the weather is going haywire again, which means we here in Vermont, and a lot of people throughout Earth's Northern Hemisphere are going to have plenty of extreme and bizarre weather over the next week or so.

THE PATTERN:

The polar vortex, that whirlpool of very cold air that pretty much always wanders around the Arctic, or at least near it, all the time has split into two pieces. That's rare, but it does happen occasionally.

One piece is ending up roughly over central and northwestern Canada, while the other piece is somewhere around Siberia. That means western North America and parts of Europe and interior Asia are turning quite cold.

The split in the polar vortex means another big squirt of warm air will enter the far northern Arctic, including around the North Pole. (This has been going on a lot lately.)

That's bad, because it's been very warm (for them) across much of the Arctic most of this winter. Sea ice extent is running at record lows.

That burst of above freezing air coming in for the high Arctic will just make things worse.

UNITED STATES SCREWED, TOO

Meanwhile, down here in the United States, a big, strong ridge of high pressure - basically an out of season Bermuda High, is about to pump record warm temperatures into the eastern third of the nation.

Out west, the position of one piece of the polar vortex means it's going to be quite cold over the next several days in the western third of the United States. Again, that's bad. It's been incredibly warm in California all winter. Plants and crops are blooming much earlier than normal as a result.

This cold air is going to nip lots of agricultural crops, especially in California's Central Valley. Hard freeze warnings are up, and it looks like the too-early blooming plants are going to get nailed. I expect millions of dollars in agricultural losses because of this. There also might be some shortages of produce in your supermarket.

More inland, winter storm warnings, watches and advisories are up for wide areas of the Rockies and northwestern Plains state.

Big chunks of The eastern half of the country is in trouble with this weather pattern, too. The orientation of this Bermuda high will help draw massive amounts of moisture from the Gulf of Mexico, leading to repeated rounds of torrential rains in a broad band from Texas to Michigan.

Many - but not all -  of these areas have had quite a lot of rain this month already. Some areas from northeastern Texas through Arkansas and into southern Ilinois could get seven or more inches of rain over the next week. There is a high chance of flooding, as you'd imagine.

VERMONT EFFECTS:

We barely got clipped by that storm that zipped by to our south last night. Most of us got one to three inches of snow, with a little less around Burlington and up to six inches and southern and eastern parts of the state.

It's kind of mild today, and some of the snow is starting to melt. But you haven't seen anything yet!

After the 30s today, it'll get into the 40s Monday and 50s to low 60s Tuesday and Wednesday. That's definitely record territory.  This will be an unusually humid warm spell for this time of year. When the air is moist, snow tends to melt much faster than when the air is dry.
The start of a thaw. Snow sliding off my St. Albans, Vermont
roof today clings to the eaves in foot-long sheets. With
forecasts for highs near 60 by Tuesday and Wednesday,
this snow will be gone soon. 

Also, partly because of the humidity, temperatures will remain extremely warm Tuesday might.

Lows early Wednesday will probably stay above 50 degrees in the Champlain Valley. That's normal for late May, not February! That'll keep the snow melt going at a fast clip.

Also, there will be a fair bit of rain during this, especially over northern areas, which will be closer to a stalled front.

The combination of melting snow and the rain could lead to flooding. Most of Vermont and northern New York is now under a flood watch Monday through Wednesday.

The biggest problem here is the ice jams left behind from that other mega-thaw in January. They're still there, and this thaw and rain will either dam up water behind the ice jams, make the ice jams even bigger, or move them into more populated areas.

As we found out in towns like Swanton and Johnson back in January, this can quickly lead to destructive flooding.

So yeah, we'll probably have quite a bit to talk about in the weather department over the next several days.

Saturday, February 17, 2018

Saturday Update: Surprise Friday Snow, Temporary Spring Still Coming

After much of the snow in my St. Albans, Vermont yard
disappeared in 50 degree temperatures on Thursday,
 an unexpected 3.3 inches of new snow that fell Friday
returned my property to a wintery look Saturday morning.
I was frankly a bit dismayed Friday evening as I drove home from work in Burlington, Vermont, which barely got a dusting of snow during the day, to my house in St. Albans, Vermont, where I measured 3.3 inches of new powder that came down during the day. 
Some northern areas of Vermont, like St. Albans, got more snow than expected as a cold front came through during the day. There was enough moisture in the air to wring out when the cold front invaded.

When I said yesterday that, regarding this early preview of spring, results would vary. They did.

A more expected storm is still expected to hit southern New England tonight, with a quick burst of five to 8 inches of snow likely in most of Connecticut, Massachusetts and Rhode Island. Similar amounts are likely near or just north of New York City. 

But that will be it for winter for the next several days as the long awaited big thaw is still coming.  The new snow in southern New England will almost certainly be melting rapidly by Sunday afternoon.

It's already developing as warm air builds in the Southeast and off the Southeast coast. There were record highs in the low 80s Friday in North Carolina. While that warmth has temporarily subsided down there, it will resurge - all the way to New England next week.

All the picky details still need to be worked out. Nobody knows exactly where warm fronts and cold fronts will set up, and when they will go through our region.

If fronts stall close to Vermont Monday through Wednesday, the warmth will be tempered by clouds and rain, but it will still be warm -- with unseasonable readings in the 50s. If the sun breaks through, it could get ridiculous, with temperatures maybe topping 60 degrees.

Places as far north as southern New England could reach 70 degrees. Like I said, insane!

Also, like I noted yesterday, despite the oncoming warmth, winter is NOT over. I'm absolutely certain we'll have at least an occasional bout in March with mid-winter style cold and snowstorms.