Friday, September 26, 2014

Does A Mild End Of September Correlate To "Warmer" Winter?

...The short answer seems to be ...YES!

Ah. But wait. Before you start to jump for joy think that this delightful weather with cloudless days, temperatures in the 70s and cool nights means an easier winter ahead like we had in 2010-11,  2011-12 and 2012-13, let me explain what I mean when I say yes.

The operative word here is "correlation". Its like saying that when I cut my finger nails, the weather is cold. These two events might correlate very well but they are far from causal.

Our 8 day forecast calls for a streak of 70+ degree days through at least the 3rd and possibly the 4th of October. If this forecast verifies, the average temperature (day and night) from the start of the 70 degree streak (September 24th) to the projected end would be 65.6 degrees or 19th all-time.

So I checked the years that ranked higher than this projection. Here is the list. It's interesting to note that the end of September last year was a mirror image of this year!  Also notice that 2007, 2005 and 2002 were warmer than this year during the same period.

By blending the years after from 1900 through last year, we get a near normal to slightly above normal temperature pattern Ohio south.

If we remove the years before 1950, we get an even milder result.

However, when we examine the physical drivers of the overall pattern and plug in the years that match up, we get this analog:  (WINTER OUTLOOK SPOILER).  WHOA....HUGE DIFFERENCE!

While this beautiful weather is something to behold, be careful in tying this late September, early October warm period to future trends. More often than not, it doesn't work.

Thursday, September 18, 2014

Why Are We Skeptical About Weather Forecasts?

(2nd Edition)

Weather is just as much psychology as it is science. Call it "Behavioral Meteorology".

Most people find it very difficult to grasp the fact that the weather is one big approximation. Not surprisingly, we humans hate approximations and probability. Why? For our minds to grasp probabilities and randomness, we need to be able to handle multiple possible outcomes at once.  The problem is that we are all wired to simplify uncertainty. We want life to be basic and easy to understand. Weather is no different. We all want a forecast that fits a nice and neat one-size-fits-all package.  Unfortunately, weather has many, many outcomes over a large area over a significant period of time. Change the initial weather conditions (humidity, wind flow, frontal position, upper level energy, etc.) and you create more uncertainty. Factor in length of time and the probability becomes significantly higher. We envision an area of rain approaching as a uniform “blob” which moves over our house at say 5:20pm and leaves at 7:15pm. Unfortunately, the actual rain area (or lake effect snow stream) rarely evolves into a tidy, uniform entity.  Instead, it has jagged edges, dry pockets and other random protrusions that impact local forecasts in a few minutes time.  See the problem?

I'd like to say that I make a forecast, short or long term, with a cold, rational, scientific eye but I don't.  I take into account how the general public will react to EVERY word knowing that most people selectively perceive the weather to fit their "sphere of reality". It’s in our DNA.   I learned that real quick after my first major lake effect snow event.

For all of the complex simulations, super-computers and highly detailed satellite data, it doesn't matter how exact your forecast is or what scientific reasoning you use in creating your forecast.  People will ignore the facts and the data that disagree with their perceptions and will "rationalize" what they want and react accordingly. More often than not, the reactions are very critical. Worse still, it’s accumulative. The more we selectively perceive the weather to fit our negative connotation, the more hyper critical our reaction and the more rigid our bias becomes. It’s a vicious circle that feeds on itself. This is called the Disconfirmation Bias. It’s the tendency to accept supportive evidence of a belief uncritically, but to discount evidence that challenges that belief.

Recently, many have already postulated that this "cooler" summer and this cool mid-September is proof that this upcoming winter will be cold and snowy. It’s a classic example of the RECENCY EFFECT: This is the tendency to think that more recent trends and patterns we observe (which are more recent in our minds like our recent mild winters) are a very good representation of the entire period in question. We believe our memories and observations--recent warmth and humidity--are excellent predictors of what the near future will bring. Throw in the thousands of weather apps out there that claim to provide the forecast for YOUR location along with the Old Farmers' Almanac and the laundry list of cognitive biases (some mentioned above) and you have the confluence of many psychological elements that are difficult to overcome with rational discussion.

It all goes back to basic human nature: We simplify complex, probabilistic themes. We all love a good story. It’s hardwired in our DNA. A boring data driven paragraph by itself only activates Broca’s area and Wernicke’s area of the brain. Brain scans show that if you incorporate emotional stories with descriptive metaphors, it will active multiple sensory parts of the brain like the Motor Cortex (body movements) and the Insular Cortex (emotional region) at once. We instinctively turn the story into our own personal experience! Given that personal stories make up more than 65% of our conversations, this makes perfect sense.

A weather forecast is no different. A narrative or story is desired versus something data/science driven. Nebulous weather data, probabilistic outcomes and other hard to grasp weather ideas makes most of us feel uncomfortable even if the on-air meteorologist has the best of intentions. Sophisticated computer models have come a long way in recent years in deriving more detailed outcomes for weather events and situations. Models are getting better as more data becomes available to be assimilated into these computer models. Yet a level of uncertainty still remains and we humans don’t like it! We try to rationalize the irrational yet our brains fight us tooth and nail. It wants a good story not boring data. Our biases quickly dismiss the probabilistic science as irrelevant or at the very worst, an excuse.  We then settle on a good story instead.

Each day, I analyze the science and remember the psychology. I try to tell a compelling, relatable weather story with a dash of data, some description of probability and a bit of historical perspective. Human nature is a powerful beast. Each person is different. Sometimes it works for the viewer. Sometimes it doesn’t. 

How do you react when you hear a weather forecast? Do you dismiss the science? Do you like the story? How do you handle probability? Do you like hearing an explanation to why the weather does what it does? Do you overly simplify the weather?

Let me know what you think. 

Tuesday, September 16, 2014

Remnants of Hurricane Ike Revisited

I'm a few days late in publishing this but it's worth a look back anyway. On September 14, 2008, the remains of Hurricane Ike (then a tropical depression at best) moved through the mid west and the Great Lakes ultimately falling a part in southern Canada.

I remember distinctly having to cut up several trees that fell in my backyard only to find that they all had Poison Oak growing throughout. Needless to say, the next two weeks were very uncomfortable.

Two distinct elements were present that allowed Ike to not only hold together but move more than a thousand miles inland. A strong high pressure cell was parked off of the east coast. A strong mid-latitude cold front was sliding across the central of the US. Both acted as a funnel focusing the storm north and east. The upper level pattern was perfectly aligned to drive the surface pattern.
500 mB heights from September 8th to September 15th

Wind gusts across northern Ohio topped out at 71 mph in northern Lorain County.
Rainfall amounts across northern Ohio were very high.

Tropical storms have impacted Ohio before. Remember Hurricane Katrina in 2005? How about Hugo back in 1989?  Here are a few notable storms NOT including Hurricane Sandy as it deserves its own post which you can read HERE.

Wednesday, September 10, 2014

Wednesday 9/10 RADAR UPDATES


Current OHIO temperatures

Current Ohio Valley radar loop
Central Great Lakes sector loop

Tuesday, September 09, 2014

Huge Temperature Changes...Severe Weather Possible

It's not all that unusual to see large temperature changes driven by strong cold fronts this time of year. Even though it is technically still summer, the sun isn't as strong as it was in early August. The early pushes of cooler air are becoming stronger and larger in extent.  The polar jet stream is starting to become a more dominating force driving mid latitude systems the US and Canada much faster and with more punch. The front forecast to push through the Great Lakes late Wednesday/early Thursday is a prime example.

HUGE temperature contrast along the front.
Incidentally, last year almost to the day, we had a similar cold front and huge temperature contrast. We went from 96 and 95 to 62 in under 48 hours!

Atmosphere is very buoyant.
 Precipitable water values are well over 2 inches!
Jet stream winds are very strong. Right-rear quadrant of the jet streak (diverging air aloft) over the mid-west will enhance the severe storms as they pass over Indiana and western Ohio.
Storm Prediction Center continues to show a slight risk for severe storms into northwestern Ohio for late Wednesday and early Thursday.
At this writing, line of storms should pass through northern Ohio between midnight Thursday and Thursday at 6am.
Temperatures will fall into the upper 50s and lower 60s Saturday.

The cool push of air is very strong and will envelop the northern 2/3rds of the US.

Tuesday, September 02, 2014

How Did This Summer Compare To Similar "Cooler" Summers?

Good day everyone. Now that the meteorological summer period is behind us, let's recap the weather in Cleveland from June through August.  A twitter follower reminded me that you can make numbers say what you want them to say. I responded to him saying that I always aim to paint a broad statistical picture with any weather recap to eliminate any biases and preconceived notions. Prior to the end of August, most of us had already involuntarily created our own narrative about summer before it had ended! So I try to combat the psychology with objective analysis while being cognizant of how people will perceive the numbers I present.

Enough of that, here is what I found. Remember, the time period is from June 1st through August 31st. Here is a quick look at the temperatures versus average across the US and North America. Much of the US especially the interior had temperatures around 1 to 3 degrees below average.

For Cleveland, the average temperature over the 3 months was the coolest in 10 years!

We forget about the summers in the early 2000s and a few in the 1990s.  
2004 and 2000 were far cooler than 2014.

The real temperature story was the number of days below 80 degrees. This summer ranked 5th highest of any summer since 1935.

Summer rainfall was especially high as it was last summer and in 2011.

14.84" was 5th highest in the last 30 years.

The number of days with more than ONE INCH of rainfall was not impressive...

...yet the frequency of 1/4 inch rain events was the 2nd highest (one shy of the record--21--set in 1902) since record keeping began in Cleveland in 1871!

Prior to the late 1920s, the official measurements were taken in downtown Cleveland. Since then, Hopkins Airport is the official location.

* In summary, the summer was the COOLEST since 2004

* The number of days below 80 degrees was the highest since     

* Most don't remember that 2004, 2000 and 1992 had more

* Rainfall was almost 5 inches ABOVE AVERAGE, 5th  
   highest in 30 years

* The number of 1/4" rain events was 2nd all-time. Only 1975 
   and 1957 matched this summer