Cold Wave to Hit the Pacific Northwest With Some Lowland Snow Possible

Some of us may have been feeling safe here in the Northwest, as extraordinary cold has hit the Midwest and the eastern U.S.. 

Soon we will  be feeling the sting of cold temperatures and even the potential for lowland snow.

The coldest air of the winter will reach our area on Sunday, and Monday's temperatures in western WA may not get above freezing.  Savage cold and wind will hit the Bellingham area.  Eastern WA will make an icebox seem warm.  The mountains will get plenty of snow and some of the lowlands we be whitened.

You might want to get prepared on Saturday--winterize your home (e.g., remove hoses from faucets),  gas up your car, make sure the antifreeze is up to snuff, and move your pets inside after Sunday AM.  Our region will have to pay extra attention to making sure our homeless folks are in warm places.

We are close enough in time that I have confidence that the upcoming cold wave will be a reality, so let me start by showing you the forecast of the UW WRF modeling system.    The following maps show sea-level pressure (solid lines) and temperature around 2500 ft (colors).   Yellow and orange are relative warm.  White and light blue indicate just cold enough to snow to sea level.  Dark blue and purple are much colder and "snow friendly."  You don't want to know about white.

Today at 4 PM, moderate temperatures are over most of the domain, with a low center and front offshore.  It will rain tonight and Friday.

Fast forwarding to Saturday at 4 PM, very cold air is moving southward into British Columbia.  Note the large pressure gradient at the leading edge of the cold air.  We often call that the "Arctic Front."

By 4 PM Sunday, the cold air has reached Washington State and there is a large pressure difference north of Bellingham, which will drive cold, gusty flow into NW Washington.  Yes...cold enough to snow.

By 4 PM Monday, the entire NW is in the freezer. But keep in mind, this is not the primo cold air.  The Cascades and Rockies will protect us from that.  (We get "modified" Arctic air).  The really cold stuff will move southward into eastern Montana  (see below).

How confident are we that the cold air will reach us?  

To evaluate that let's take a look at the National Weather Service ensemble output for Seattle's surface temperature (the temperatures of many model runs are shown, each slightly different in how they start).  They are all going for a major  cool-down, with most showing that Monday will barely get to freezing as the day-time high.    It will be cold bike-ride for me to work that day.

What about snow?   The pattern that is being forecast is not a huge snow producer over the lowlands, but the models are suggesting that certain lowland areas will get snow.  

I will talk about this more in a future blog, but here is the forecast 24-h snowfall ending at 4 PM Sunday.  You will notice a band of light snow extending across Everett and Snohomish county.   That is from the convergence of strong, cold flow coming out of the Fraser River Valley hitting southerly flow coming up Puget Sound.  

The next 24 hr snowfall is similar, with NW Washington getting snow, with higher amounts near Port Angeles and Sequim as the cold air is forced to rise over the Olympics.  Snow over eastern WA  and NW Oregon.

Folks...there is a lot of uncertainty in this snow pattern.  We need to wait a day, when the high-resolution forecasts will become available. And while we get hit by cold and snow, Chicago and East Coast will warm dramatically.

from Cliff Mass Weather and Climate Blog http://bit.ly/2Geotyc

Cold Wave to Hit the Pacific Northwest With Some Lowland Snow Possible

Some of us may have been feeling safe here in the Northwest, as extraordinary cold has hit the Midwest and the eastern U.S.. 

Soon we will  be feeling the sting of cold temperatures and even the potential for lowland snow.

The coldest air of the winter will reach our area on Sunday, and Monday's temperatures in western WA may not get above freezing.  Savage cold and wind will hit the Bellingham area.  Eastern WA will make an icebox seem warm.  The mountains will get plenty of snow and some of the lowlands we be whitened.

You might want to get prepared on Saturday--winterize your home (e.g., remove hoses from faucets),  gas up your car, make sure the antifreeze is up to snuff, and move your pets inside after Sunday AM.  Our region will have to pay extra attention to making sure our homeless folks are in warm places.

We are close enough in time that I have confidence that the upcoming cold wave will be a reality, so let me start by showing you the forecast of the UW WRF modeling system.    The following maps show sea-level pressure (solid lines) and temperature around 2500 ft (colors).   Yellow and orange are relative warm.  White and light blue indicate just cold enough to snow to sea level.  Dark blue and purple are much colder and "snow friendly."  You don't want to know about white.

Today at 4 PM, moderate temperatures are over most of the domain, with a low center and front offshore.  It will rain tonight and Friday.

Fast forwarding to Saturday at 4 PM, very cold air is moving southward into British Columbia.  Note the large pressure gradient at the leading edge of the cold air.  We often call that the "Arctic Front."

By 4 PM Sunday, the cold air has reached Washington State and there is a large pressure difference north of Bellingham, which will drive cold, gusty flow into NW Washington.  Yes...cold enough to snow.

By 4 PM Monday, the entire NW is in the freezer. But keep in mind, this is not the primo cold air.  The Cascades and Rockies will protect us from that.  (We get "modified" Arctic air).  The really cold stuff will move southward into eastern Montana  (see below).

How confident are we that the cold air will reach us?  

To evaluate that let's take a look at the National Weather Service ensemble output for Seattle's surface temperature (the temperatures of many model runs are shown, each slightly different in how they start).  They are all going for a major  cool-down, with most showing that Monday will barely get to freezing as the day-time high.    It will be cold bike-ride for me to work that day.

What about snow?   The pattern that is being forecast is not a huge snow producer over the lowlands, but the models are suggesting that certain lowland areas will get snow.  

I will talk about this more in a future blog, but here is the forecast 24-h snowfall ending at 4 PM Sunday.  You will notice a band of light snow extending across Everett and Snohomish county.   That is from the convergence of strong, cold flow coming out of the Fraser River Valley hitting southerly flow coming up Puget Sound.  

The next 24 hr snowfall is similar, with NW Washington getting snow, with higher amounts near Port Angeles and Sequim as the cold air is forced to rise over the Olympics.  Snow over eastern WA  and NW Oregon.

Folks...there is a lot of uncertainty in this snow pattern.  We need to wait a day, when the high-resolution forecasts will become available. And while we get hit by cold and snow, Chicago and East Coast will warm dramatically.

from Cliff Mass Weather and Climate Blog http://bit.ly/2Geotyc

Are Cold Waves Increasing Under Global Warming? The Answer is Clearly No.

The coldest temperatures of the winter have hit the central and eastern U.S. and misinformation about its origin is now spreading around social and traditional media.

President Trump, of course, tweets about the cold wave, suggesting that global warming has left us, and hopes for its return.  Absolutely untrue.  A cold wave, such as the one hitting the U.S. says nothing about the existence of global warming caused by increasing greenhouse gases.

And then a number of supposedly reputable media outlets, such as the NY Times and the WA Post, that are giving play to the hypothesis that global warming is causing more cold waves, through the "lazy jet stream" mechanism pushed by Dr. Jennifer Francis of Woods Hole and Dr. Judah Cohen. of a private sector firm, AER.

These claims are clearly false:  the observational evidence is very clear:  there are LESS cold waves today than in the past.   Which is exactly what we would expect in a warming world.

Global warming is NOT causing more cold extremes, it is doing the OPPOSITE.

Let me show you analyses produced by U.S. government experts.

The U.S.  Environmental Protection Agency did a study of the trend of cold wave days from 1948 to 2015.   The found very few locations where cold waves were becoming more frequent, but lots of locations in the western U.S. and the East Coast where cold waves were become less frequent, with the West Coast showing a huge decline of cold waves (see below).

A plot of the area in the U.S. covered by extreme cold over the past century (again by EPA) shows a decided decline in cold daily lows.

What about statistics from NOAA?   Here is a plot for the National Climate Data Center on the changes in winter cold extremes over the U.S.  The minimum temperature extremes are warming, not getting colder.  Extreme cold waves are weakening.

And a global view of the trend in daily temperature extremes around the world compared to the global warming signal shows that extreme lows are warming FASTER than the overall global warming signal.  So extreme cold waves are weakening quickly

Trend in the temperature of the coldest day of the year as a multiple of the global mean temperature rise. Source: NOAA/NCEI/GHCN-D stations with at least 50 years of data via the KNMI Climate Explorer.

I could show you much more, but the facts are clear.  There is no increasing trend in cold waves as claimed in the NY Times and other media.  Observations demonstrate that cold waves are declining in magnitude as the Earth warms. 

This makes complete physical sense.   Global warming is preferentially warming the Arctic and northern latitudes, the source region of the cold air that moves southward in cold waves.  And there is little evidence for the "lazy jet stream" theory in observations.

I for one find it really disturbing the such obviously false information is being communicated by major media outlets.  

from Cliff Mass Weather and Climate Blog http://bit.ly/2HCfbi1

Are Cold Waves Increasing Under Global Warming? The Answer is Clearly No.

The coldest temperatures of the winter have hit the central and eastern U.S. and misinformation about its origin is now spreading around social and traditional media.

President Trump, of course, tweets about the cold wave, suggesting that global warming has left us, and hopes for its return.  Absolutely untrue.  A cold wave, such as the one hitting the U.S. says nothing about the existence of global warming caused by increasing greenhouse gases.

And then a number of supposedly reputable media outlets, such as the NY Times and the WA Post, that are giving play to the hypothesis that global warming is causing more cold waves, through the "lazy jet stream" mechanism pushed by Dr. Jennifer Francis of Woods Hole and Dr. Judah Cohen. of a private sector firm, AER.

These claims are clearly false:  the observational evidence is very clear:  there are LESS cold waves today than in the past.   Which is exactly what we would expect in a warming world.

Global warming is NOT causing more cold extremes, it is doing the OPPOSITE.

Let me show you analyses produced by U.S. government experts.

The U.S.  Environmental Protection Agency did a study of the trend of cold wave days from 1948 to 2015.   The found very few locations where cold waves were becoming more frequent, but lots of locations in the western U.S. and the East Coast where cold waves were become less frequent, with the West Coast showing a huge decline of cold waves (see below).

A plot of the area in the U.S. covered by extreme cold over the past century (again by EPA) shows a decided decline in cold daily lows.

What about statistics from NOAA?   Here is a plot for the National Climate Data Center on the changes in winter cold extremes over the U.S.  The minimum temperature extremes are warming, not getting colder.  Extreme cold waves are weakening.

And a global view of the trend in daily temperature extremes around the world compared to the global warming signal shows that extreme lows are warming FASTER than the overall global warming signal.  So extreme cold waves are weakening quickly

Trend in the temperature of the coldest day of the year as a multiple of the global mean temperature rise. Source: NOAA/NCEI/GHCN-D stations with at least 50 years of data via the KNMI Climate Explorer.

I could show you much more, but the facts are clear.  There is no increasing trend in cold waves as claimed in the NY Times and other media.  Observations demonstrate that cold waves are declining in magnitude as the Earth warms. 

This makes complete physical sense.   Global warming is preferentially warming the Arctic and northern latitudes, the source region of the cold air that moves southward in cold waves.  And there is little evidence for the "lazy jet stream" theory in observations.

I for one find it really disturbing the such obviously false information is being communicated by major media outlets.  

from Cliff Mass Weather and Climate Blog http://bit.ly/2HCfbi1

Are Cold Waves Increasing Under Global Warming

The coldest temperatures of the winter have hit the eastern U.S. and misinformation is now spreading around social and traditional media.

President Trump, of course, tweets about the cold wave, suggesting that global warming has left us, and hopes for its return:

And then a number of supposedly reputable media outlets, like the NY Times and the WA Post, are giving play to the hypothesis that global warming is causing more cold waves, through the "lazy jet stream" mechanism pushed by Dr. Jennifer Francis of Woods Hole and Dr. Jacob. of a private sector firm, ERT.   


Let's clarify this once and for all:  the observational evidence is very clear:  there are LESS cold waves today than in the past, which is exactly what we would expect in a warming world.

The U.S.  Environmental Protection Agency did a study of the trend of cold wave days over the past 50 years.   The found very few locations where cold waves were becoming more frequent, but lots of locations in the western U.S. and the East Coast where cold waves were become less frequent, with the West Coast have a huge decline of cold waves (see below).

A plot of the area in the U.S. covered by cold periods (again by EPA) shows a decided decline in cold daily lows.

And a plot of the percent of daily record highs are increasing, but daily lows are decreasing since the 1970s (again from EPA).

from Cliff Mass Weather and Climate Blog http://bit.ly/2WtoBjh

Are Cold Waves Increasing Under Global Warming

The coldest temperatures of the winter have hit the eastern U.S. and misinformation is now spreading around social and traditional media.

President Trump, of course, tweets about the cold wave, suggesting that global warming has left us, and hopes for its return:

And then a number of supposedly reputable media outlets, like the NY Times and the WA Post, are giving play to the hypothesis that global warming is causing more cold waves, through the "lazy jet stream" mechanism pushed by Dr. Jennifer Francis of Woods Hole and Dr. Jacob. of a private sector firm, ERT.   


Let's clarify this once and for all:  the observational evidence is very clear:  there are LESS cold waves today than in the past, which is exactly what we would expect in a warming world.

The U.S.  Environmental Protection Agency did a study of the trend of cold wave days over the past 50 years.   The found very few locations where cold waves were becoming more frequent, but lots of locations in the western U.S. and the East Coast where cold waves were become less frequent, with the West Coast have a huge decline of cold waves (see below).

A plot of the area in the U.S. covered by cold periods (again by EPA) shows a decided decline in cold daily lows.

And a plot of the percent of daily record highs are increasing, but daily lows are decreasing since the 1970s (again from EPA).

from Cliff Mass Weather and Climate Blog http://bit.ly/2WtoBjh

Dramatic Display in the Northwest Skies Today: Super Contrails and Hole-Punch Clouds

I got nearly a dozen emails this afternoon with pictures, mainly from folks around Anacortes and north Whidbey Island to Bellingham, of some very strange cloud formations--namely weird holes in a large deck of clouds.   Here are some examples:

 Courtesy of Tony Bigge

 Courtesy of the Stringmans of North Whidbey Is.

Courtesy of Jason Reid of Bellingham

No...these were not alien incursions into WA air space, but the impact of aircraft passing through a cloud deck of supercooled water (liquid water at 32F or below).   The planes climbing or descending through the clouds caused the supercooled water to turn to ice crystals and fall out, living a circular hole.  These features are also known as "punch hole" clouds and often form in mid-level altocumulus cloud decks.

Now what really got me excited is that the new high-resolution GOES-17 weather satellite actually viewed these from space!  Don's believe me?  Then take a look below!  Absolutely amazing. 

But the fun today didn't end there.  We had one of the most amazing contrail days, with huge numbers of them filling the skies..... check out these NASA MODIS images from around 1 PM.  See all the little lines?  Those are contrails in a high deck of cirrus clouds.

 The air was at or close to saturation and the addition of moisture and particles from jet engines produced the multitude of cloud lines.

A picture from the Seattle PanoCam at 8:10 AM this morning said it all:  contrails, low clouds, and a wonderful sunset--with Mt. Rainier in the distance.  What could be better?

from Cliff Mass Weather and Climate Blog http://bit.ly/2FU46XR

Dramatic Display in the Northwest Skies Today: Super Contrails and Hole-Punch Clouds

I got nearly a dozen emails this afternoon with pictures, mainly from folks around Anacortes and north Whidbey Island to Bellingham, of some very strange cloud formations--namely weird holes in a large deck of clouds.   Here are some examples:

 Courtesy of Tony Bigge

 Courtesy of the Stringmans of North Whidbey Is.

Courtesy of Jason Reid of Bellingham

No...these were not alien incursions into WA air space, but the impact of aircraft passing through a cloud deck of supercooled water (liquid water at 32F or below).   The planes climbing or descending through the clouds caused the supercooled water to turn to ice crystals and fall out, living a circular hole.  These features are also known as "punch hole" clouds and often form in mid-level altocumulus cloud decks.

Now what really got me excited is that the new high-resolution GOES-17 weather satellite actually viewed these from space!  Don's believe me?  Then take a look below!  Absolutely amazing. 

But the fun today didn't end there.  We had one of the most amazing contrail days, with huge numbers of them filling the skies..... check out these NASA MODIS images from around 1 PM.  See all the little lines?  Those are contrails in a high deck of cirrus clouds.

 The air was at or close to saturation and the addition of moisture and particles from jet engines produced the multitude of cloud lines.

A picture from the Seattle PanoCam at 8:10 AM this morning said it all:  contrails, low clouds, and a wonderful sunset--with Mt. Rainier in the distance.  What could be better?

from Cliff Mass Weather and Climate Blog http://bit.ly/2FU46XR