Extreme Weather Weekend: Cat 5 Lorenzo, Huge Western Snows, Storms, California Twister?

Giant Hurricane Lorenzo in the central Atlantic
Ocean this morning. 

Time to update one of those weekend when the weather across the nation and parts of the world have once again kind of gone off the rails.

There's a couple videos at the bottom of this post.

So let's get going:

WILD HURRICANE LORENZO

Yesterday, I joked a little about Hurricane Lorenzo, in relation to ex-tropical storm Karen. But Hurricane Lorenzo really wowed the weather world last night.

Lorenzo is way out over the central Atlantic, and is no threat to land with the very notable exception of the Azores, which are really under the gun from this storm.

At the end of the week, Lorenzo was a high-end category 4 hurricane, and it was arguably the furthest east in the Atlantic Ocean for such a strong storm. Water temperatures are usually cooler in the eastern half of the Atlantic Ocean than in the western  half, at least in the northern hemisphere.

That means those eastern hurricanes tend not to get as strong as those more to the west, since hurricanes crave the warmest water possible to thrive.

Last night, Lorenzo pulled a fast one on everybody. It was expected to slowly weaken as it moved northward over the open water. And it was weakening Friday night and the first half of Saturday.

Lare Saturday night, though, Lorenzo blew up into a category 5 monster with 160 mph sustained winds. Luckily it wasn't near land. This is easily the strongest hurricane on record in the eastern half of the Atlantic. Also the furthest north we've seen a category 5 hurricane.

Meteorologist Phil Klotzbach (@philklotzbach) posted this map. The dot in blue
is where Category 5 Hurricane Lorenzo was. The red dots
are where all other Category 5 hurricanes developed. You
can see ho far east Lorenzo is

As Dennis Mersereau notes in Forbes, and citing meteorologist Eric Blake, the previous record for the furthest east Category 5 was Hurricane Hugo in 1989, which was a good 600 miles west of Lorenzo's position. (Mersereau is @wxdam on Twitter.)

A number of weather experts I've seen on line say this could easily be another sign of climate change. The water in the eastern Atlantic is now warmer than it used to be decades ago, so this region can support more intense storms.

There certainly has been an uptick in unusually strong Atlantic hurricanes in recent years. As Mersereau writes:

"Lorenzo is the second category five hurricane we've seen in the Atlantic Ocean so far this year, and the sixth such storm to form in the Atlantic in the last four years."

As Lorenzo moves north into cooler waters, it will finally weaken and transform into a regular mid-latitude storm. It could bring strong winds and heavy rain to the British Isles toward the end of the week, we'll have to wait and see.

ROCKIES SNOW

A lovely September day in Choteau, Montana Saturday

It usually snows in the northern Rocky Mountains in September, but not like this!

Some areas, especially in the mountains, can expect a good three feet of snow by the time things taper off Monday night or Tuesday.

Since leaves are still on the trees in many areas, the heavy wet snow is causing a lot of damage to forests, street trees and powerlines. Livestock is suffering and crops are being ruined.

According to meteorologist Jonathan Erdman (@wxjerdman on Twitter), Great Falls, Montana has 9.7 inches of snow Saturday. That's the snowiest September day on record there. It also would have been the snowiest October day in Great Falls. Erman said you'd have to go to November 8, 2012 to find a snowier day in Great Falls.

Over in Spokane, Washington, they had their first September snowfall since 1926. And it was quite a bit considering the season - 1.9 inches.

Cut Bank, Montana has been snowy, with temperatures in the upper 20s and wind chills in the lower teens since Saturday morning.  That would be rather unpleasant by January standards here in Vermont.

CALIFORNIA SUPERCELL

A relatively rare supercell thunderstorm developed about midway between San Francisco and Sacramento, California Saturday evening. It produced a possible tornado near Davis, and dumped several inches of hail on one area, including a stretch of major highway.

There was also a smattering of severe storms in the mid-Atlantic states, and in and around Missouri yesterday. One especially strong storm hit a Christian music festival in Pennsylvania Saturday, blowing tents around and injuring six people.

RECORD HEAT

Intense heat continued in the Southeast Saturday, with many more records being set.  This state of affairs will continue into the middle of the week.  I expect several cities in the East and Ohio and Tennessee Valleys to set all-time records for the month of October.

Several cities in the Southeast and Deep South are having their hottest September on record.

VERMONT IMPACTS

The Green Mountain State will mostly miss the wild weather over the next couple of days. But things will still be interesting. And very changeable.

Yesterday actually felt humid in Vermont ahead of a cold front. Now that front has gone by, and it's cool and sunny. It's going to be a gorgous Sunday for leaf peepers (though most places aren't at peak yet.)  Look out tonight, as there will be scattered frost around, especially away from Lake Champlain.

After another nice day Monday, a warm front will come in with some rains for Tuesday. If skies clear enough briefly before a cold front approaches, highs in some parts of Vermont could top 80 degrees

It appears this cold front will give us a good slug of rain especially Wednesday.

Then it will cool down dramatically. It won't be anything too out of the ordinary for October, but it will come as a shock because it's been rather mild lately. By the end of the week and next weekend, highs will only be in the upper 40s to mid 50s.  A hard freeze is beginning to look like a fairly good bet next weekend. It could even snow on the mountain peaks.

Yeah, I just said the "s" word.

Some videos:

Possible tornado in Davis, California Saturday:



Incredible amounts of hail on a highway near Davis, California Saturday after a tornado-warned
supercell thunderstorm went by:



And a bit of time spent outdoors in Montana Saturday:

Worst Nightmare Comes True: Dorian Razes N. Bahamas; Florida Fears Continue

Your daily dose of Hurricane Dorian. Here it is this morning, slamming
the northern Bahamas. Outer rain bands are beginning to affect Florida
with gusty showers and beach erosion.

An EF-4 tornado, which has winds of between 166 and 200 mph, would severely damage or destroy your house, even though a tornado only lasts at most a few minutes in any one location.

Now imagine such a tornado sitting over your house for most of the day.

That's basically what the northern Bahamas have been experiencing yesterday and today as incredible Category 5 Dorian basically sits and churns in place.  

Images coming out of the Bahamas, most of them taken while the relatively calm eye of Dorian was over the Abaco Islands, are heartbreaking.

very structure was badly damaged by then, and the people in the wreckage faced many more hours of extreme winds after the eye passed.

Cars were thrown around like leaves on a breezy autumn afternoon.  The formerly lush landscape, now stripped of leaves, looked more bleak than a dark, foggy, cold Vermont November day. Dorian's storm surge looked more like a tsunami.

In the eye of the storm, terrified residents somehow found their way to Twitter, begging people to pray for them. It's all too much.

Videos are at the bottom of this post, in case you need proof.

Dorian was, and is, incredible.  With sustained winds of 185 mph Sunday, it was the furthest north an Atlantic Category 5 has gotten east of the Gulf of Mexico. That's what you get when the ocean water is so warm. Warmer than normal, possibly in part due to climate change.

Dorian's winds had fallen to "only" 165 mph as the storm sat and spun over Grand Bahama Island overnight and this morning, with pretty much no forward movement. Freeport in the Bahamas expected sustained winds of 100 mph for 12 to 18 straight hours.

The National Hurricane Center pleaded with Bahama residents not to venture outside in the calm eye of the storm. When the hurricane moves just a little, the extreme winds would suddenly be back, killing anyone who was outdoors.

Now there's Florida. The National Hurricane Center and most forecasters are still confident that after its long stall over the Bahamas, Dorian will turn north, taking advantage of a weak spot in a high pressure system that had steered the storm into the Bahamas.

But Dorian's turn north will come perilously close to the Florida east coast. Actually closer to the coast than some of the more optimistic forecasts earlier this weekend. Some computer models are insisting on bringing Dorian ashore somewhere in eastern Florida.

It's a nail biter, for sure.

Even if Dorian doesn't make it ashore, its dangerous eyewall, where the strongest winds are located, could brush along parts of the Florida east coast. Hurricane and storm surge warnings are in effect for most of the central east coast of Florida.

Already, there is some beach erosion and gusty winds in eastern Florida. Stuart, Florida reported a gust to 54 mph from an outer Dorian rain band this morning.

There are signs that Dorian might be going through something called an eyewall replacement cycle this morning. This is common in strong hurricanes and I'm surprised it didn't happen with Dorian sooner. Eyewall replacement cycles tend to decrease the top wind speeds in a hurricane, which is good. But it also expands the area experiencing strong winds. Which of course is bad, especially for Florida in this case.

Then Dorian will brush past Georgia and the Carolinas, risking more trouble and damage. They're already evacuating people from coastal locations in those states.

True, in a couple, few days, Dorian will not be as strong as it was and is over the Bahamas, it will still be a powerful, dangerous hurricane. We're only halfway through this drama.

Videos:

One of the Abaco Islands in the Bahamas during the eye of the storm Sunday. Notice how the cars had been tossed around as if a toddler had a tantrum with his Matchbox cars




Another video, probably taken during the eye of the storm. It's an apartment building or motel, with its roof gone, debris inside with people inside, too. Then a walk down the hallway to see the extreme storm surge outdoors:



Dorian's storm surge looked more like a tsunami:

https://www.nhc.noaa.gov/text/refresh/MIATCPAT5+shtml/021224.shtml

Social Media Notwithstanding, Things Are NOT Chill With Hurricane Dorian

Category 5 Hurricane Dorian in an incredibly awesome
satellite shot this morning

Hurricane Dorian continued to be an extremely dangerous storm. As of this morning, it has been upgraded as a worst case Category 5 storm, with sustained winds of 160 mph, says the National Hurricane Center. Yes, it managed to strengthen even more overnight. It's slowly churning its way into the northern Bahamas.

By the way, Dorian makes this the first known time there have been Category 5 storms in the eastern Atlantic on four consecutive years.

The tone on some of social media yesterday was, "Oh, this is great. Dorian is going to miss Florida, and might miss the Carolinas. All is good."

Not so fast.

First of all, we need to deal with the Bahamas. We'll get into Florida a bit further down in this post, and things aren't all that rosy in the Sunshine State.

A hurricane this strong is bad enough. When it stalls and sits over pretty much one spot, like Dorian is likely to, it's exponentially worse. You saw the destruction Hurricane Michael caused in the Florida Panhandle last year.

Michael was moving right along, and unleashed the bulk of its destruction in just a few hours.

Imagine having to deal with 100 mph sustained winds for 30 straight hours, like Freeport in the Bahamas could experience. The longer the winds blow, the more opportunity for things to blow away and people to get hurt or killed.

Granted, buildings in the Bahamas are often basically concrete fortresses to ward off hurricanes, but they can only take so much. Plus the couple feet of rain or more they are going to have to deal with isn't easy, either.

Now, let's get into Florida. As I've kept saying all week with Dorian, forecasting the track of a hurricane isn't easy. It's especially difficult when steering currents collapse, as is happening with Dorian. That's why it's stalling out in the Bahamas.

Dorian was moving steadily westward, propelled by a high pressure system north of it. So at least the storm had some sort of meteorological "guidance" that made it comparatively easy to predict where it was going.

Now, Dorian is entering an area with no strong steering currents. Subtle little features in the atmosphere can play a big role in where Dorian goes. And since Dorian is going to get so close to the Florida coast, there's no room for error. But there will surely be errors in forecasting, because this is such a difficult situation to predict. Every mile counts as to how badly this will affect Florida.

The forecast still has Dorian making a hard right turn Tuesday and Wednesday, moving northward offshore, parallel to the Florida coast.

But what if that right turn happens just a little later than currently forecast? In that case, Dorian could still come ashore in eastern Florida as a major hurricane. That's not the official forecast, but the National Hurricane Center still has eastern Florida in the so-called "cone of uncertainty."

That means the NHC is acknowledging that Florida could still be in play here.

Even if Hurricane Dorian somehow behaves exactly as forecasters think it will (Ha!) the central east coast of Florida is in for a nasty few days.

There's a tropical storm warning for that region, and meteorologists have upgraded the wind forecast for populated areas like West Palm Beach, Melbourne, Port St. Lucie and Palm Bay. Winds there could go to 74 to 110 mph, especially if Dorian nudges just a few miles closer to the coast than currently expected.

As Dorian is a slow mover, this part of Florida might endure at least tropical storm conditions from late tonight into Wednesday. That's a long time to have to deal with this.

We won't even get into the threat in the Carolinas later in the week. That's still definitely in play.

Dorian has probably reached peak intensity this morning. You'll probably hear starting today and going into Monday, Tuesday and Wednesday that Dorian is "weakening" so everything's OK, right.

Or not. True, it will probably weaken. Winds with Dorian three days from now might "only" be, say, 120 mph. That's still a problem, isn't it?

I don't mean to be Mr. Gloom and Doom, because there's still a great chance this won't be a worst case scenario for anywhere in the United States. But people in the areas to be affected by the storm should not let their guard down. It could still be a helluva ride.

Hurricane Michael Upgraded To Rare Category 5 Storm At Landfall

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It turns out Hurricane Michael, which devastated parts of the Florida Panhandle and surrounding areas last October 10, was even stronger than first thought.

It was a rare landfalling Category 5 hurricane, the strongest you can get. It had previously been regarded as a higher end Category 4, but a re-analysis has determined the extremely powerful hurricane was even a little worse than everybody assumed.

According to a statement Friday from NOAA's National Hurricane Center:

"Michael is the first hurricane to make landfall in the United States as a Category 5 since Hurricane Andrew in 1992, and only the fourth on record. The others are the Labor Day Hurricane in 1935 and Hurricane Camille in 1969. Michael is also the strongest hurricane landfall on record in the Florida Panhandle and only the second known Category 5 landfall on the northern Gulf Coast."

Hurricane Michael was originally thought to have made landfall with top sustained winds of 155 mph, which is a high end Category 4. But it probably had sustained winds 5 mph higher, at 160 mph.

As a practical matter, the 5 mph difference has little real-life effect. The storm would have been pretty much as destructive if winds were "only" 155 mph instead of 160 mph. The top sustained winds of 160 mph probably occurred in a very small area around Mexico Beach, and Tyndall Air Force Base, Florida.

But the new designation helps demonstrate how extreme Michael was. The upgrade in the storm's intensity came after the National Hurricane Center reviewed wind measurements from aircraft, reports of surface wind measurements air presure, satellite intensity estimates and Doppler radar data. This includs a lot of data and analysis that was not immediately available at the moment Michael roared ashore, says NOAA.

Most hurricanes weaken as they approach a coastline, because friction with land usually interferes with the storm's air flow. Hurricane Michael kept strengthening right up to the moment of landfall. There's no telling how strong it would have gotten had it gone through more warm ocean water before reaching shore.

Only a few recorded hurricanes, like Hurricane Charley in southwestern Florida in 2004, strenghten rapidly until landfall. This type of hurricane is obviously extremely dangerous. People in the hurricane zone might have been expecting a weaker hurricane, only to confront a monster like Michael.

With this in mind, Hurricane Michael is sure to be studied extenstively going forward. Meteorologists will want to understand why some hurricanes strengthen dramatically as they approach the coast, like Michael did. Better forecasting in such situations will surely save lives.

I also think scientists will want to better understand whether climate change makes it more likely that hurricanes could pull a Michael and get much more dangerous as they come ashore.

Meanwhile, the people who suffered the effects of Hurricane Michael are probably not caring whether the storm had 155 or 160 mph winds. It'll take years to clean up the mess. CBS News said some people were still living in tents six months after the storm.

Hurricane Michael will also present dangers for years. About 350,000 acres of northwest Florida pine forests were completely destroyed by the hurricane. Another 4.6 million acres are damaged.  All that fallen timber presents a big wildfire danger, reports Scientific American.

Already, there has been on pretty good sized fire near Panama City, and there will probably be more.
All this is more proof that hurricanes don't really end when the winds die down. In some ways, they continue on for years.