A Beautiful Day on Friday After One of the Worst Winters in Years

The complaints have been non-stop, with even Northwest natives mumbling about one of the most persistently wet, cool, cloudy winters they can remember.

But tomorrow (Friday) will be better, with a transient ridge of high pressure over us, bringing dry conditions and temperatures rising in the upper 50s F.

Here is the surface air temperature forecast for 5 PM Friday from the high-resolution UW WRF model. The dark orange (over Seattle) indicates 56-60F, with 60s in eastern WA and parts of southwest Washington.    I am looking for my sunglasses tonight.

But a single beautiful day does not make up for a challenging winter.  Before I describe it, did you you know that SmartAsset real estate site has ranked Seattle as having the most depressing winters of any major city in the lower-48 states?  This is based on the percentage of a sunshine rate and average solar radiation (see below).  Only far north Anchorage is worse for the U.S. as a whole.

So I guess we start with low expectations.  But this winter takes it one step further.  Here is the number of days during the past six months with at least a trace of rain.  115-145 out of 180 in western Washington/Oregon were wet.

But the real depressing aspect of this winter is the continuation of the clouds and rain into late February and March, when major improvement is normally observed.   Here are the number of days during the past 60 days with some rain.  OMG... large swaths have had 50-55 days of rain out of 60 days (83-92%).   This is way more than normal (typically in March in Seattle 55% days have some rain).  MUCH worse than typical.

One of the faculty in my department, Dale Durran, has a solar array on his house. This March had far less power output than any of the five years the system was in place.

All the moisture and clouds has resulted in very wet soils, something shown by the NASA GRACE instrument that can measure soil moisture from space (below).  Blue is highly saturated.  My backyard is a mud pit now.

Our future?  Some showers on Saturday, mostly dry on Sunday, warming into Tuesday.  But the moisture returns, with the Climate Prediction Center's 6-10 day precipitation forecast covering our areas with the wet green colors.  Sorry.

__________________________

Help Support Regional Climate Research at the UW

Society needs to know the regional impacts of climate change and the UW is building a regional climate modeling effort.  With Federal funding collapsing, we are trying a community funding approach.  If you want more information or are interested in helping, please go here.  The full link is: http://ift.tt/2nltDeR

from Cliff Mass Weather Blog http://ift.tt/2nluIn7

A Beautiful Day on Friday After One of the Worst Winters in Years

The complaints have been non-stop, with even Northwest natives mumbling about one of the most persistently wet, cool, cloudy winters they can remember.

But tomorrow (Friday) will be better, with a transient ridge of high pressure over us, bringing dry conditions and temperatures rising in the upper 50s F.

Here is the surface air temperature forecast for 5 PM Friday from the high-resolution UW WRF model. The dark orange (over Seattle) indicates 56-60F, with 60s in eastern WA and parts of southwest Washington.    I am looking for my sunglasses tonight.

But a single beautiful day does not make up for a challenging winter.  Before I describe it, did you you know that SmartAsset real estate site has ranked Seattle as having the most depressing winters of any major city in the lower-48 states?  This is based on the percentage of a sunshine rate and average solar radiation (see below).  Only far north Anchorage is worse for the U.S. as a whole.

So I guess we start with low expectations.  But this winter takes it one step further.  Here is the number of days during the past six months with at least a trace of rain.  115-145 out of 180 in western Washington/Oregon were wet.

But the real depressing aspect of this winter is the continuation of the clouds and rain into late February and March, when major improvement is normally observed.   Here are the number of days during the past 60 days with some rain.  OMG... large swaths have had 50-55 days of rain out of 60 days (83-92%).   This is way more than normal (typically in March in Seattle 55% days have some rain).  MUCH worse than typical.

One of the faculty in my department, Dale Durran, has a solar array on his house. This March had far less power output than any of the five years the system was in place.

All the moisture and clouds has resulted in very wet soils, something shown by the NASA GRACE instrument that can measure soil moisture from space (below).  Blue is highly saturated.  My backyard is a mud pit now.

Our future?  Some showers on Saturday, mostly dry on Sunday, warming into Tuesday.  But the moisture returns, with the Climate Prediction Center's 6-10 day precipitation forecast covering our areas with the wet green colors.  Sorry.

__________________________

Help Support Regional Climate Research at the UW

Society needs to know the regional impacts of climate change and the UW is building a regional climate modeling effort.  With Federal funding collapsing, we are trying a community funding approach.  If you want more information or are interested in helping, please go here.  The full link is: http://ift.tt/2nltDeR

from Cliff Mass Weather Blog http://ift.tt/2nluIn7

The Yakima Warm Anomaly: A Local Weather Mystery

Since 2011, a number of folks have noted that the temperatures at Yakima Airport (YKM) seems too warm compared to surrounding locations.  A few years ago, Bud Graves, past head of the Yakima NWS office, noted that tree fruit growers found that Yakima temperatures had become less reflective of the vegetative development of the area, being too warm.  YKM has a long record and is considered the key weather observation in the Yakima Valley.

And when temperatures are plotted on maps, a warm bull's eye is often apparent around Yakima.

Let me show you.  Here is a plot of the number of days over the last two years that the temperature exceeded 90F.   There is a localized maximum (dark red) near Yakima (a map, with Yakima County indicated, is also shown for reference).

What about average minimum temperature?   Another localized warm maximum around Yakima.   In fact, Yakima has the warmest low temperatures in the state!

A plot of the high temperatures yesterday around the Yakima area, show the Yakima Airport (YKM) is warmer than any place else in the neighborhood (63).

So what is going on at the Yakima Airport?   It is something of a mystery.  The National Weather Service says they checked out the sensor and it seems to be calibrated ok.  The Yakima instrument suite is typical of U.S. airports: NWS/FAA ASOS (Automated Surface Observing System).

Using Google Maps, there is an image of the airport area, with downtown Yakima to the north and east.  The oval shows the location of the Yakima weather instruments.

And here is a blow up of the weather instruments area.  The instruments are in a vegetated area between two runways.

So what is going on?   The airport is relatively low, so that would contribute to daytime warmth, but not at night.  The vegetation is dry, so it would warm up more than irrigated fields, but that doesn't explain the nighttime warmth.  And besides, some of the cooler neighborhood weather instruments are on unirrigated land or in urban areas.  The neighboring runways could warm up during the day and perhaps release heat at night.

The high resolution UW WRF model forecast for 5 PM Monday (below) does not suggest a warm bullseye over the airport--so it does not indicate some strange (but real) local weather feature.

There have been a number of reports (and publications) bringing into question the sensor used in the NWS ASOS stations:  the H0-83 hydro-thermometer (see picture).   These papers (example here) suggest a number of possible problems, including insufficient ventilation of the enclosure (the white object below).

So the origin of the warmth at Yakima is still not clear, but the reported start in 2011 does suggest some instrumentation issue.

Finally, this example explains something many of you have asked in the comments...why are there isolated warm and cool areas on the climatological maps I show (like the average maximum temperature map over the past two years below).  The answer is probably bad sensors or unrepresentative locations (like a sensor near a building or over concrete).  My discipline needs to do better.

from Cliff Mass Weather Blog http://ift.tt/2offm59

The Yakima Warm Anomaly: A Local Weather Mystery

Since 2011, a number of folks have noted that the temperatures at Yakima Airport (YKM) seems too warm compared to surrounding locations.  A few years ago, Bud Graves, past head of the Yakima NWS office, noted that tree fruit growers found that Yakima temperatures had become less reflective of the vegetative development of the area, being too warm.  YKM has a long record and is considered the key weather observation in the Yakima Valley.

And when temperatures are plotted on maps, a warm bull's eye is often apparent around Yakima.

Let me show you.  Here is a plot of the number of days over the last two years that the temperature exceeded 90F.   There is a localized maximum (dark red) near Yakima (a map, with Yakima County indicated, is also shown for reference).

What about average minimum temperature?   Another localized warm maximum around Yakima.   In fact, Yakima has the warmest low temperatures in the state!

A plot of the high temperatures yesterday around the Yakima area, show the Yakima Airport (YKM) is warmer than any place else in the neighborhood (63).

So what is going on at the Yakima Airport?   It is something of a mystery.  The National Weather Service says they checked out the sensor and it seems to be calibrated ok.  The Yakima instrument suite is typical of U.S. airports: NWS/FAA ASOS (Automated Surface Observing System).

Using Google Maps, there is an image of the airport area, with downtown Yakima to the north and east.  The oval shows the location of the Yakima weather instruments.

And here is a blow up of the weather instruments area.  The instruments are in a vegetated area between two runways.

So what is going on?   The airport is relatively low, so that would contribute to daytime warmth, but not at night.  The vegetation is dry, so it would warm up more than irrigated fields, but that doesn't explain the nighttime warmth.  And besides, some of the cooler neighborhood weather instruments are on unirrigated land or in urban areas.  The neighboring runways could warm up during the day and perhaps release heat at night.

The high resolution UW WRF model forecast for 5 PM Monday (below) does not suggest a warm bullseye over the airport--so it does not indicate some strange (but real) local weather feature.

There have been a number of reports (and publications) bringing into question the sensor used in the NWS ASOS stations:  the H0-83 hydro-thermometer (see picture).   These papers (example here) suggest a number of possible problems, including insufficient ventilation of the enclosure (the white object below).

So the origin of the warmth at Yakima is still not clear, but the reported start in 2011 does suggest some instrumentation issue.

Finally, this example explains something many of you have asked in the comments...why are there isolated warm and cool areas on the climatological maps I show (like the average maximum temperature map over the past two years below).  The answer is probably bad sensors or unrepresentative locations (like a sensor near a building or over concrete).  My discipline needs to do better.

from Cliff Mass Weather Blog http://ift.tt/2offm59

American Airlines to Remove TV Screens in Some Planes

Cats and Dogs May Have Similar Mental Ability, Study Finds

Japan Celebrates Native Sumo Grand Champion

Peak Snowpack Time

Historically, the snowpack over the Pacific Northwest mountains peaks right about now--the last days of March to first week in April--something that is illustrated by the figure below (a figure from Amar Andalkar's wonderful skiing the Cascade volcanoes site).

This year the regional mountain snowpack surged in early March, but has stagnated the last week or so because of warmer weather, something illustrated by the snowpack numbers at the Olallie Meadows SNOTEL site near Snoqualmie Pass (dark blue is this year's snow water equvalent, SW), light blue is normal.

Why does our snowpack hit its maximum around April 1, a time when the sun is getting quite strong (equivalent to mid-September)?

Before we talk about that, here are the latest snowpack numbers (percent of normal) around the West.  Virtually all the West is well above normal for SWE (total amount of water in the snowpack), with California's Sierra Nevada being crazy high.

As noted by Mark Albright, past state climatologist, with 720 inches of snowfall through 23 March, Mt Baker Ski Area has recorded its snowiest winter since the big snow years of 2011-12 with 808 inches and 2010-11 with 857 inches.  This is going to be a  long ski season for the Northwest.  Enough snow that Washington DOT is delaying its clearing of North Cascades Highway (SR20);   according to WA DOT it may be the latest opening since 1974.  This WSDOT photo of SR 20 near Liberty Bell mountain shows some of the challenges, including several avalanche shoots.

So why does Cascade snowpack peak around April 1?   It is all about temperature.  Since our weather systems come off the Pacific, it is good to look at the vertical sounding at Qullayute, on the NW WA coast.  Below are the climatologies of temperature there for three levels (925 hPa--around 2500 ft, 850 hPa--around 5000 ft, and 700 hPa--around 10,000 ft).  Those levels pretty much bracket the Northwest high terrain.  You will notice that they have a similar characteristic:   temperatures aloft don't start warming until mid-April.  I talked about that in a previous blog---the atmosphere has a lot of thermal inertia, which means it takes a while for the increasing warming at the surface to influence the deeper atmosphere. 

And there is another issue, snow is highly reflective, so a lot of the sun over the mountains is reflected to space rather warm the surface.    This is an issue regarding our regional impacts of global warming.  As the earth warms, our mountain snowpack will lessen, which will allow more solar radiation to be absorbed, which causes more warming and thus melted snow.   A positive feedback for destroying snow and warming our region.

Those effects will become profound later in the century, but so far there have been only minimal losses of Cascade snowpack.     Larry Schick of the US Army Corps of Engineers, also known as the Grand Poobah of NW Powder, sent me some snow statistics of major regional ski areas provided by Tony Crocker (his best snow web site has lots of good material).  Both the Pacific Northwest and California ski areas show little trend (black line) through 2013.

And an analysis of snow water equivalent (SWE) of over 200 SNOTEL sites around the NW through 2016 by Mark Albright suggests little trend over the past 30 years (see below)

Now before some folks get irritated with me, let me underline that this will all change by mid-century as greenhouse gases increases.   We have been "protected" by the slow to warm eastern Pacific. but eventually the radiative effects of increasing greenhouse gases will warm the lower atmosphere even here causing substantially reduce snowpack.

Finally, what about the next week?  The latest ECMWF snow forecast shows some additional snow at higher elevations across our region.  Enjoy.

from Cliff Mass Weather Blog http://ift.tt/2n74IfG

Peak Snowpack Time

Historically, the snowpack over the Pacific Northwest mountains peaks right about now--the last days of March to first week in April--something that is illustrated by the figure below (a figure from Amar Andalkar's wonderful skiing the Cascade volcanoes site).

This year the regional mountain snowpack surged in early March, but has stagnated the last week or so because of warmer weather, something illustrated by the snowpack numbers at the Olallie Meadows SNOTEL site near Snoqualmie Pass (dark blue is this year's snow water equvalent, SW), light blue is normal.

Why does our snowpack hit its maximum around April 1, a time when the sun is getting quite strong (equivalent to mid-September)?

Before we talk about that, here are the latest snowpack numbers (percent of normal) around the West.  Virtually all the West is well above normal for SWE (total amount of water in the snowpack), with California's Sierra Nevada being crazy high.

As noted by Mark Albright, past state climatologist, with 720 inches of snowfall through 23 March, Mt Baker Ski Area has recorded its snowiest winter since the big snow years of 2011-12 with 808 inches and 2010-11 with 857 inches.  This is going to be a  long ski season for the Northwest.  Enough snow that Washington DOT is delaying its clearing of North Cascades Highway (SR20);   according to WA DOT it may be the latest opening since 1974.  This WSDOT photo of SR 20 near Liberty Bell mountain shows some of the challenges, including several avalanche shoots.

So why does Cascade snowpack peak around April 1?   It is all about temperature.  Since our weather systems come off the Pacific, it is good to look at the vertical sounding at Qullayute, on the NW WA coast.  Below are the climatologies of temperature there for three levels (925 hPa--around 2500 ft, 850 hPa--around 5000 ft, and 700 hPa--around 10,000 ft).  Those levels pretty much bracket the Northwest high terrain.  You will notice that they have a similar characteristic:   temperatures aloft don't start warming until mid-April.  I talked about that in a previous blog---the atmosphere has a lot of thermal inertia, which means it takes a while for the increasing warming at the surface to influence the deeper atmosphere. 

And there is another issue, snow is highly reflective, so a lot of the sun over the mountains is reflected to space rather warm the surface.    This is an issue regarding our regional impacts of global warming.  As the earth warms, our mountain snowpack will lessen, which will allow more solar radiation to be absorbed, which causes more warming and thus melted snow.   A positive feedback for destroying snow and warming our region.

Those effects will become profound later in the century, but so far there have been only minimal losses of Cascade snowpack.     Larry Schick of the US Army Corps of Engineers, also known as the Grand Poobah of NW Powder, sent me some snow statistics of major regional ski areas provided by Tony Crocker (his best snow web site has lots of good material).  Both the Pacific Northwest and California ski areas show little trend (black line) through 2013.

And an analysis of snow water equivalent (SWE) of over 200 SNOTEL sites around the NW through 2016 by Mark Albright suggests little trend over the past 30 years (see below)

Now before some folks get irritated with me, let me underline that this will all change by mid-century as greenhouse gases increases.   We have been "protected" by the slow to warm eastern Pacific. but eventually the radiative effects of increasing greenhouse gases will warm the lower atmosphere even here causing substantially reduce snowpack.

Finally, what about the next week?  The latest ECMWF snow forecast shows some additional snow at higher elevations across our region.  Enjoy.

from Cliff Mass Weather Blog http://ift.tt/2n74IfG