Mid-Winter 2019-20 Recap (A Little Late)

I am late in posting this as we are in the middle of the February rating period so on-air duties have come first.

So far the winter has been much warmer than we indicated in our winter outlook back in late October. What did we miss?  Why did the seasonal outlook end up being "milder"? To answer this we will look at the many drivers of the winters and compare what they were indicating in late fall versus what actually happened.

Most of the metrics describing the winter (temperatures, snowfall, etc) will come from the northern Ohio perspective. The other analyses will focus on other elements like continental and global drivers. My goal is to always give historical perspective. S

Let's start with Lake Erie ice cover:

Photo courtesy: Tom Horsman

Lake Erie ice coverage has been at historic lows (data since 1972). The ice coverage as of February 19 is now at 4.8% (daily data from GLSEA--Chart from Environment Canada) The only years close to 2019-20 on this date were 1998 (none), 2002 (7.1%), 2012 (1.7%), 2017 (2.2%)

What were the years with the lowest MAX ice levels? 1998 (8%), 2002 (10%), 2012 (14%) and this year (4.8%). Data from @NOAA_GLERL is daily data for 2020 and 2012. Other years' data is weekly ice data from Environment Canada.

How does this winter compare to last winter?

Rest of the Great Lakes are also showing little ice coverage vs last year

The winters with at least 10% or more with ice coverage over the last 10 years. We've had some lean years recently with some cold and icy Lake Erie periods like the winters of 2013-14 and 2014-15.

Here is are the seasonal snowfall maps starting with this winter 2019-20 all the way back  to the winter of 2013-14 for comparison

Another way of comparing winters is to use the AWSSI (Accumulated Winter Season Severity Index). It takes into account snowfall, extreme temperatures and other factors. Notice how low this winter has been even compared to last winter. Below is the winter 2019-20 vs recent winters, winter of 2004-05 (snowiest winter in northern Ohio), winter 2013-14 (one of the coldest recent winters) and the coldest winter (1977-78)

This winter started out very promising with early November snowfall:

November temperatures ended up below normal across the eastern US. Notice the ridge of high pressure over the Gulf of Alaska. We thought this would be the precursor to the overall winter pattern...

Ridge over GOA started to break down. Bermuda high retrograded west. Temperatures in early December started to trend up.

Low over Alaska/western Canada developed in mid-December. Temperatures continued above normal across much of the US.

Our overall winter outlook highlighted temperatures above normal for December.  The holiday season across Ohio was one of the warmest on record. Warm was similar to the same period in 1982

The northern Pacific pattern (EPO - East Pacific Oscillation) is highly connected to our temperatures in northern Ohio. Notice how it was below normal in November and early December.  Then the EPO started a sharp increase as the northern Pacific ridge started to shift.

We're we worried about the warm December temperatures/lack of snow pointing to a warmer winter overall?  Nope.  At this point, we anticipated the pattern to gradually shift to more sustained periods of cold.  We highlighted these locations where we analyzed ocean temperatures. This configuration would be more favorable (among other factors) for a weakened Polar Vortex and high pressure "Blocking" over Greenland.

This November/December temperature set-up happened during the winter of 2014-15 so it wasn't without precedent. Notice that we had a very mild winter then the bottom fell out that winter in January and February.

So what actually happened in January this year?

We had a weak, warm El Nino signature (still do as of late February). Notice the warmth below centered near the dateline with cooler water in the ENSO 1.2 region (closer to South America).












 The dateline warmth increased slightly over the last 2 months (see graph below)










BY ITSELF (key words here), the placement of ENSO warmth during El Nino winters can play a significant role on the type of winter (cold or not-so cold)






Based on the past warm/neutral ENSO years (AGAIN BY ITSELF), January and February looked colder than normal (top row). But that didn't happen.....

The ridge in the northern Pacific became MUCH stronger in the first half of the month. The effects downstream were pronounced: Above normal temperatures eastern 2/3 of US

Why did this happen? The MJO (Madden Julian Oscillation) played a big factor as the MJO was in favorable high amplitude phases for cold initially (November) then warmth in January and became a large driver of the warmth.



November: MJO was in a favorable COLD phase









 
The MJO went around the dial in January with high amplitude/phases 4-5-6 which favored warmth

Eventually, the high pressure settled over the central US. The result was continuous above normal temperatures. A bubble of "cooler" air in the central US started to pop up as a panhandle storm track started to develop by the end of the month

The pattern started to change in early February. The ridge in the northern Pacific was strong similar to early January as was the Bermuda high. However the placement of the ridge centers made all the difference in the storm track. The jet stream (center box below) steered storm systems out of the panhandle of Texas with actual storm origination in the central Pacific. A weak northwest track across the northern states shifted the track further east into the Ohio Valley.

As of this writing, we have had 6 panhandle storm systems cross the Ohio Valley

The storm track throughout the winter has been on target. (Image courtesy Larry Cosgrove)

In summary here's the globally ocean temperatures comparing October to late January:

The cooler water in the eastern Indian Ocean started to warm #1 below. The ENSO region near the dateline (#2 below) remained consistent along with cooler water near South America (#2 below).The Gulf of Alaska warm pool cooled slightly (#3 below). The Indian Oceanic Dipole (IOD) which was at record positive levels in late fall (this significantly influenced the Australian fires) started to fall which is common as the water in the eastern Indian Ocean started to warm.

This takes us to the arctic where the cold air has been locked up overt the North Pole. The Polar Vortex hasn't become dislodged for long periods. The polar jet has been strong.

The Stratospheric Vortex (upper atmosphere) has also been strong. It's been sitting and spinning in a uniform pattern.

In years when the Polar Vortex is weak, cold air outbreaks are more frequent and stronger.

We look for rapid warming in the upper atmosphere and sharp wind reversals. Last winter (2018-19) the temperatures rose at 50 hPa and the zonal winds dropped and shifted direction (see below). 

The jet stream was strong in spots in December 2018. The jet started to buckle in January which resulted in well below normal temperatures across the Great Lakes in January 2019

This winter (2019-20) the 50 hPa temperatures stayed at near record low levels with zonal winds at near record high levels.  

Notice the difference between last winter and this winter. The jet stream was strong in spots in December just like 2018. Unlike January 2019 when the jet started to buckle, the jet in this winter intensified shutting down the cold air across the US.

January 2020 temperatures

Look at the surface pressure over the arctic. Lows around the North Pole. Ridges below in the lower latitudes.

Also no Greenland Blocking (high pressure ridge). In fact the exact opposite. 

The teleconnections (AO/Arctic Oscillation and NAO/North Atlantic Oscillation) have been in a dominant positive phase. Notice the LOW over Greenland similar to this winter

POSITIVE Arctic Oscillation

Dr. Judah Cohen from AER has a great blog in which he describes the arctic behavior each winter and the variables that influence its changes week to week. Here are his thoughts on the feedback mechanism that has kept the Polar Vortex so strong from his February 10th entry:

"...But the incessant stretch of positive to strongly positive AO since late December, based on the polar cap geopotential height anomalies (PCHs) plot originated in the polar stratosphere with cold/negative PCHs/strong PV back in mid December that propagated to the surface over a course of two weeks (see Figure i). And ever since, the two (strong PV – positive AO) have been locked in an infinite loop. Cold/negative PCHs/strong PV favor a positive AO and a positive AO with the lack of high latitude blocking/zonal (straight west to east) jet stream favor a strong PV. And to be honest there is no built-in circuit breaker to stop this infinite loop other than internal/natural variability where wave breaking can help to disrupt the PV (for such an example see Leet et al. 2019)."

He continues (and echoes what I have surmised as a possible driver (IOD and MJO) of the strong PV):

"...Arctic sea ice extent is also not conducive to disrupting the Polar Vortex. For much of the winter the greatest negative extent anomalies have been on the North Pacific side of the Arctic and not the North Atlantic side. This asymmetry in sea ice anomalies favors a strengthened PV and not a weakened PV, at least based in some modeling experiments (e.g. McKenna et al. 2017). Please don’t interpret this last point as trying to attribute the strong PV/positive AO solely to Arctic forcing. It seems highly plausible to me that the positive Indian Ocean dipole and strange behavior of the Madden Julian Oscillation (stuck in an infinite loop of its own between phases 4-6) have played an important role in the positive AO winter, especially given that it was predicted by the models this past fall. I

The overall results for this winter in northern Ohio and a large portion of the US has been one of the warmest winters on record:

3rd warmest in northern Ohio since 1932

Snowfall across Ohio Valley and Great Lakes vs normal

Here are the metrics we use in comparing seasons. Data is for Hopkins Airport. All data found HERE

We forget the very mild winter of 2015-16 and some of the snowy winters between 2010 and 2015 along with the early 2000s winters which featured more snow than the winters of the late 1970s!

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We are left with several questions. Why did the winter end up much warmer than our October winter outlook indicated?

1) How much did the Indian Ocean (IOD) shift influence the MJO during the winter influence the strength of the northern hemispheric (polar) jet and the stability of the arctic?

2) How much--if any--did the central weak, neutral "El Nino" play a role?

3) How much did Climate Change influence this winter?

4) How much did the Arctic sea ice play a role?

5) Any other variables?

If you have any research on these ideas and would love to shed light on these question, contact me on Twitter (scottsabolfox8).  Thank you in advance!

Common Weather Misconceptions, Myths and Analogies

Many wonder why I write so much about the psychology of weather. If you read the comments on most of my posts over the years you'll see why. Many will believe what they want to believe. They use social media as a conduit to say whatever impulsive thoughts they want without recourse science be damned. Bias and perception become the ultimate reality.

I use social media and my blog--since 2005--to show why weather events occur the way they do. I post statistics, records and graphical charts about past weather to show some perspective. I think I'm successful most times. Unfortunately a significantly large percentage of the social media audience are not receptive much to my dismay.

So rather than use technical, long winded science to explain the why we do what we do, I'm taking a straight forward approach (with some dry humor and sarcasm) to drive home some points:

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1) It WILL snow at some point between February and early April. It always does.

2) The warm weather in winter plays with our minds.  Our weather perceptions (cognitive biases) are very strong.  We are not immune.  We are all human.  Recognition of these preconceived notions is the first step in an objective understanding the weather and the science that governs it. Public perception is very powerful.

3)  We humans hate forecast uncertainty. Heck, we all hate uncertainty of any kind really. Here's why LINK

4) Contrary to what you might believe, weather forecasts are more accurate than they were 15 years ago.  According to this study, "the accuracy of the 8-10 day forecast today are similar to a 5-7 day forecast 15 years ago. Hurricane accuracy is greatly improved since Hurricane Katrina LINK.

4a) Many people say that TV weather forecasts were better/more local/more accurate in the 1970s or 1980s. Totally disagree. Look one up on Youtube. Those forecasts look pretty antiquated.

4) Our morning show here at FOX 8 in Cleveland is 6 hours (4am to 10am). I have 41 weather segments, headlines and teases. I will repeat myself. The weather forecast between 4 and 10am can change as the conditions change. Forecasts are not frozen in time during each weather segment.  The weather doesn't stop for television.

5) The decision to break into a popular TV show or sporting event with a weather update is NOT an impulsive one. Stations have different philosophies on when to break into programming. I can't speak for the others. However, my station WJW-FOX 8 only breaks during a tornado warning or a significant winter weather event (widespread, blizzard-like snow which doesn't happen every year). We treat those weather events very seriously especially when people's lives are threatened.

6) Most television weather maps typically show the weather in two dimensions which by their nature don't paint a complete picture. Imagine the atmosphere (especially during sleet, freezing rain events) like layers of a wedding cake.  Each layer of icing represents the different layers of air at different temperatures with different types of precipitation.

Note: The wedding cake analogy is mine and mine alone. I invented it :)

8)  In reality, the atmosphere is a three dimensional, ever changing fluid. Complex equations are used in describing its behavior. Many television meteorologists took classes in thermodynamics, cloud physics, years of calculus and differential equations. Its not as easy as looking out the window https://journals.ametsoc.org/doi/10.1175/MWR-D-17-0257.1

7) Moon or sun halos are not uncommon. They are beautiful sights caused by the bending, splitting and reflecting of sunlight through ice crystal clouds.  Double rainbows are super common. We have hundreds of photos from viewers. Call me when you see a tertiary rainbow!

8) I grade my long range outlooks. (I've added the extreme temperatures category) Here is an example from the winter  of 2018-19.

8) I'm not a fan of phone weather apps that promise super-local weather forecasts for your backyard every 15 minutes. They are like unicorns.  They truly don't exist as promised.  Most phone app forecasts are created from computer generated model data that's approximated based on your location via your phone's GPS.  I will always trust a human generated forecast app (via NWS or your local tv station like FOX 8) every day of the week. Also, a radar app is a must for everyone.

9) Jet contrails are not chem-trails.  They, like unicorns, don't exist.  I don't like conspiracy theories.

10) I have no control of weather, news or school closing promos that run many times per hour. The promotions department is on the first floor.

11) Yes, pre-Christmas warmth is unusual but its happened before. Remember 1982?  Remember 2019?

12) Simply because the weather has been warm or cold in your area, wet or dry doesn't confirm or deny climate change. It's more complicated than that. It never fails. People on social media will invariably post evidence--usually what they observe in their backyard over time--confirming their preconceived notions.  See number 2 above for the reasons why.  There are many reputable sites and sources on Climate Change.

14) I consider myself an operational meteorologist who happens to be on television. I constantly read research papers, articles on new forecasting techniques and other weather posts from other meteorologists so that I can incorporate these new developments/forecasting techniques into my on-air segments. The science has come a long way.

13) We forget that the 2000s was the snowiest decade in northern Ohio NOT the 1970s

14) The term Polar Vortex is not new. Yes, it's real (LINK)

15) "Panhandle Hooks" in winter typically feature wetter snows from the southwest. Please don't call it a "Panhandle Hooker".

16) Contrary to what we believe, you cannot use one or two days or even a weeks worth of weather as a predictor of the season ahead. For example, a warm or cold December is not an indicator of the spring or summer ahead. A super wet spring/early summer (2019 for example) doesn't mean the rest of the summer will be wet/little heat. Basically the drivers of winter or any season aren't necessarily the drivers of next season. It's not an apples to apples comparison. I wish it was. (Remember December 2014 was warmer than normal.  Then the bottom fell out: January through February in Cleveland was the 6th coldest on record, coldest since 1978)

17) Seasonal forecasts are like grandma's casserole. There are many ingredients. You change one ingredient and, just like the taste of grandma's casserole, the outlook will be totally different.

18) The Lake Erie water temperature is taken at a depth of 30 feet near the water intake a few miles offshore. There are also satellite measurements taken each day which are available FREE online.

19) There is a TON of science behind seasonal outlooks. The Farmers' Almanac is not science (although I enjoy reading it).  Weather consulting companies issue seasonal outlooks tailored for their clients. This is a multi-million dollar enterprise and it continues to grow significantly.

20) Many readers will ignore everything I typed here and replace it with their own conclusions regardless of their validity.

I reserve the right to add to this list.

I hope this helps :)

COMPLETE Lake Erie Ice Cover History Since 1972

Here is the Lake Erie ice coverage percentage for EACH DAY since the start of the winter of 1972-73 color coded.

0% to 0.09% Grey
0.1% to 0.99% Light Blue
1% to 10% Darker Blue
10.1% to 25% Brighter Blue
25.1% to 50% Light Purple
50.1% o 75% Bright Purple
75.1% to 99% White

I posted each month separately because the original image was too big...too long.

Top row is 1972-73. Bottom row is 2018-19

Per Great Lakes Environmental Research Laboratory (GLERL) "From 1973 through 1988, the source was the Canadian Ice Service. Beginning with 1989, the source was the U.S. National Ice Center, (NIC). Data from both Canadian and U.S. sources is combined in NIC's daily products."

NOVEMBER

DECEMBER

JANUARY

FEBRUARY

MARCH

APRIL

MAY

What Caused the Lake Erie Water Temperature Changes Recently?

A huge upwelling event occurred along the eastern shoreline of Lake Michigan earlier this week. Water temperatures dropped from the lower 70s to the upper 40s in under 24 hours! Why did this happen? The Grand Rapids, Michigan National Weather Service office has a great graphic that describes what upwelling is.

Can this occur along the Lake Erie shoreline here in Ohio? Absolutely. In fact, some significant temperature changes occurred about 24 hours after the Lake Michigan event just offshore near Cleveland.

I created a basic animation showing how the water temperatures fluctuated earlier this week especially as depths between 20 and 40 feet. One short-lived drop of around 10 degrees at 23 feet, steadier drops at 30 feet with a spike of more than 20 degrees at 30 feet. At 40 feet, water temps rose from 52 to 75 degrees in under 24 hours. Below that depth, water temperatures have been consistently near 50-55 degrees.

Lake Erie water temperature colorized depth map shows the variation under the surface

A sustained north wind developed Tuesday and Wednesday...

Wave heights had a big spike as the north wind took over.

North wind and higher wave heights match up with the drop in temperature.

Thankfully the bulk of the colder water didn't make it all the way to the surface. Temperatures went from 79 to 73 degrees at this buoy. Temperatures stabilized over the next 24 hours

Bottom line is never under estimate the influence the north wind has on Lake Erie conditions. The higher waves are the changes we see on the surface. The rough conditions under the surface either through strong rip currents or temperatures drops to levels that can cause hypothermia are not as obvious and lesser known.