Monday, April 28, 2014

Severe Weather Update; Frequent Rains for Ohio Valley

James Bryant, Associated Press
The fatality free start to the tornado season ended yesterday (Sunday, April 27th) when an 11 month old baby was killed following a roof collapse. This was the longest stretch without a tornado fatality since 1915!  We can thank a colder than normal winter with a jet stream that kept unstable air away from the US. Add to that the high resolution radar grid across the country which gives us much better lead time when tornadic weather strikes.

Here in northern Ohio, severe weather threat will be small but the rainfall totals will be significant through late Wednesday.

Severe weather will develop today across northern Mississippi, Alabama and central Tennessee. Moderate risk across the deep south.

Current radar images for Central Tennessee and northern Mississippi and Alabama.

Friday, April 25, 2014

Summer Outlooks Are Different Than Day-to-Day Forecasts

Our WJW FOX8 Summer Outlook first aired on Thursday, April 24th. Not long after, comments and criticism started pouring in stating in part that we should concentrate on getting the daily forecast right rather than trying to forecast the weather months out. This isn't new. It happens after each seasonal outlook.

Actual day to day weather forecasts are developed with analyzing current conditions, radar, satellite and other parameters to make a forecast for a short period of time in the future. 12 Hours, 24 hours, 36 hours, 48 hours. We utilize computer model projections as guidance. Yes, these projections are getting better as more data is utilized and plugged into faster and faster computers with more sophisticated equations.

Seasonal long range outlooks (winter weather forecast, etc) are created by looking at the ocean sea surface temperature patterns (El Nino, etc), pressure patterns over the Arctic and North Atlantic among some other long term atmospheric trends. Some scientists use solar output and other variables. The elements just mentioned are matched up with other years of occurrence.  A best possible fit is created. Sometimes this works out well.  Sometimes it doesn’t.  Again, this is a trend outlook not a specific forecast for a specific day. Individual storms cannot be seen this far out. Forecasts for specific days? Forget it. Too much randomness in the atmosphere that is way beyond our abilities. But by looking at parameters that existed in the past during other storm events, we can say that the chance of say a hurricane making landfall is greater this year than in years past. 

For most, all of these forecasts and trend outlooks are lumped into one group even though each are derived using entirely different information. I get it. Its human nature to generalize and simplify complicated subjects like the science of weather prediction. So as a result, we formulate a concrete, black and white, overly scaled down version of the weather.  Whether its a long range winter outlook, a climate average for a wedding day, the thunderstorm chances for later this afternoon, lake effect snowfall amounts or a hurricane forecast track. Its all the same animal to most. We subconsciously eliminate the nebulous science, weird looking equations and fancy internet computer animations in favor of a narrative that tells a better story.  In short, The Old Farmers’ Almanac fits with how our brains are wired.  Its simple. Its folksy with just enough science to make it credible.  Why do we continue believing the Old Farmers’ Almanac?  The simple answer is it makes us feel good!  While I love the Old Farmers Almanac for its articles, I'd trust an actual Meteorologist's forecast first.  I wouldn't preemptively dismiss the scientific explanation, ignore the random changes and replace them with the Old Farmers Almanac figuring that its more accurate.  Just saying...

So remember that Seasonal Outlooks are by their very nature formulated differently than day-to-day forecasts.  Let's sit back and see if this summer will behave like we think it will.

Thursday, April 24, 2014

Is Spring Disappearing?

"It seems like we go straight from winter into summer nowadays."

Its by far one of the most frequent comments I get this time of year. But is it true? Are those traditional spring days from yesteryear being replaced by quicker transitions from winter to warmer days?

A tall order for sure. So rather than relying on our perceptions (I've written extensively how our senses and selective memory fools us by placing more weight on more recent events that match up with our inherent biases) in determining whether or not this "winter-to-summer" trend actually exists, I looked up the average temperatures each day during the meteorological spring months (March through May) over the last 50 years. I plotted the average daily temperature and ran a linear regression of all 92 days (March through May) for each year since 1964 (last 50 years) to determine the rate of warming for each spring.

For example, 2013 looks something like this: 

The "slope" if you remember from grade school math represents the trend. So in last year's case, the slope or trend was a 0.46 degree INCREASE per day from March 1st through May 31st.

That's great but that's only one year. How about the other 49 years?  I won't bore you with each temperature scatterplot but some interesting years stand out. The largest increase per day occurred in 1975. The smallest increase per day occurred in 1973.

Here are the TOP 10 and BOTTOM 10 with the year of occurrence:  Only 2 of the TOP TEN occurred in the last 20 years.
I plotted each year's trend with the trend line. The long term trend over the last 50 years is negligible.

However, the same temperature trend data in bar graph form shows HIGHER INCREASES in consecutive years since 2000 (except was 2012).  The increase over the last 15 years is steady around 0.35 degrees per day in spring. We also saw some long stretches in the 1980s equal to recent years.

The 1970s though saw WIDER VARIATION YEAR-TO-YEAR with SMALLER INCREASES compared to recent years of about a tenth a degree lower than the last 15 years. 

So when someone says "Its seems as if spring is shorter" or "We're jumping from winter into summer faster now than in past years", it seems they would be right...but for a different reason.  These changes of a few tenths of a degree over many years are imperceptible to us. My guess is that we take the short term weather changes (a sudden drop from 75 to 35 for example) and believe these changes reflect bigger changes over longer periods. Its a classic example of the RECENCY EFFECT.

Thursday, April 17, 2014

New To My Weather Blog?

Good day everyone…

While many visitors to my blog are returning customers, the site tracker shows that I get a fair amount of new readers especially during extreme weather events. If you're new here, this post will give you an idea of what to expect.

First and foremost, I’m a data guy. Show me the data that reinforces your point on a topic if applicable and I'll listen. If its in a peer reviewed paper or presentation, all the better.  No hearsay.  No opinions that poise as factual information.  No passive aggressive comment rants.  I like hardcore data. The problem is that science and data are scary topics for most people even the most science savvy individual.  The mere word “data” has cold, dark connotations. Data is antiseptic. That’s why people have a tough time relating to it. This is why politicians steer clear of spouting esoteric numbers.  So they attach an emotional component to it--a clever narrative--to attract voters. It works. Its basic human nature. But it can grossly diminish the baseline facts of any issue. Human nature allows us to forge relationships with other people. It’s the essence of the human experience. It defines who we are. Yet it can blur our vision when we perform data driven analysis of any kind. This is where Behavioral Meteorology comes into the picture.  

When I say "Behavioral Meteorology", people think that this only refers to how the changing weather conditions alter our moods and body.  While this undoubtedly occurs (ask my surgically repaired shoulder before a snow storm), my definition of Behavioral Meteorology is the study of how we perceive weather, weather forecasts and climate through our own cognitive biases and preconceived ideas. The aim of my blog is simple: Present the weather and the data in a local context with some historical perspective. When applicable, show how our preconceived notions of the weather affect our objectivity. I revisit these ideas either directly or indirectly in posts by answering some of these questions below using a myriad of charts, graphs and easy-to-understand images.

     1) How do we “perceive” the actual weather conditions, weather forecasts and past weather events?

        2) To what degree has the proliferation of weather information over the internet and most recently smart phones skewed our view on the accuracy of weather forecasts?

     3)    Has this flood of instantaneous weather information influenced the public’s view on current weather events and their place in weather history?

     4) Do people put more credence in weather folklore than in weather science?
     5)   What are the specific psychological drivers of our weather/science perceptions?  More generally--a topic for other more qualified people to answer--how do these "drivers" lead us astray on more pressing global and domestic issues outside science?

As a reader, I hope that you take a step back and do the same.

Tuesday, April 15, 2014

Tax Day Snowfall Photos

We always say that if you can make it to around Tax Day, we are pretty much in the clear from seeing snowfall. There are always today.  I distinctly remember the big snowfall (11") we had between the 23rd and 24th of April back in 2005.  It took me almost 3 hours to get home driving down I-71 that night. We've had 15 years with snowfall greater than ONE INCH on or after April 15th. Yet only 5 times over the last 40 years....before today. RADAR LOOP HERE

Here are some snow pictures from around northern Ohio. Not to worry, temperatures will hit 60 by Thursday. All of this snow will be history before you know it!

Snow on the daffodils in Medina, Ohio
Monroeville, Ohio

Norwalk, Ohio
Bellevue, Ohio

Canal Fulton, Ohio
Chesterland, Ohio

Lakewood, Ohio
Lorain, Ohio

Monday, April 14, 2014

UPDATE: Upper 70s to Snow in 2 Days!

Sadly, the headline is correct.  After this insanely long winter, should we be surprised? Probably not. CLICK ON IMAGE BELOW FOR CURRENT TEMPERATURES AND WIND. Notice the drop already occurring to the west...

In anticipation of this huge swing last Friday, I dug up the occurrences of THIRTY DEGREE high temperature drops in TWO DAYS OR UNDER with at least one inch of snow in April. It was far from easy. After digging up the instances of snowfall, I had to cross reference the high temperature declines MANUALLY in each of those years. I say this not to complain--this kind of esoteric statistical research still needs to be done the old fashioned way--but to illustrate the work involved. So an hour of sifting through data results in only a few tidbits of blog trivia which fit nicely in two blocks below.  For me its worth it, as I hope it is for you.  Here are the results:

30 degree drop or more in 48 HOURS resulting in least 1" of snow5 TIMES

  • 51 DEGREE DROP:  2007: 80 TO 29, 3" snow
  • 38 DEGREE DROP:  1969: 82 TO 44, 1.5" snow
  • 38 DEGREE DROP:  1921: 71 TO 33, 1.5" snow
  • 32 DEGREE DROP:  1912: 64 to 32, 6.5" snow
  • 30 DEGREE DROP:  1893: 71 to 41, 3.5" snow
30 degree drop or more in 24 HOURS resulting in at least 1" of snow: 4 TIMES

  • 36 DEGREE DROP:  1972: 67 TO 31, 1.7" of snow
  • 33 DEGREE DROP:  1940: 60 TO 27, 3.2" of snow
  • 31 DEGREE DROP:  1982: 63 TO 43, 1.7" of snow
  • 30 DEGREE DROP:  1988: 63 TO 43, 2.3" of snow
This drop will go from 78 Sunday to upper 30s Tuesday (48 hours) just shy of the 51 degree drop listed above. The 24 hour drop starting this morning (73 degrees to upper 30s) will be close to the ALL-TIME record one day drop set back in 1972 listed above!
I posted this map showing this potential more than a week ago illustrating the comparison to the snow event back in 2005.

Lake Erie is wide open meaning that some lake enhancement will occur tomorrow as the cold air filters in from the northwest.

The ground is warmer than a few weeks ago so a lot of melting will occur as the rain changes over to wet snow. That said, slushy accumulations will occur:

Wednesday, April 09, 2014

More Evidence of Building El Nino--Summer Thoughts

A few weeks ago, I wrote about the MEI or Multivariate ENSO Index and how this was a better overall measure of ocean-atmosphere conditions. It takes into account not only sea surface temperatures but sea level pressure, surface temperature, wind and cloud cover.

The update shows a significant increase in El Nino conditions. Given the neutral conditions that existed over the last several months, the events that best fit so far are indicated below. We have a way to go before we reach the MODERATE EL NINO events of 1986 and 2002 in their early stages.

Sub surface warmth continues to move eastward and closer to the surface similar to the El Nino event of 1997-98.
Will the MEI reach 1997 or 1982 levels by the middle of the summer?

Klaus Wolter summarizes the conditions succinctly here:

"I looked at the nearest-ranked Feb-Mar MEI values, and required an increase in their rankings from both the previous month and from Nov-Dec. Of the 9 cases selected in this fashion, three remained either neutral (1960) or dropped back to La Niña status within a year (1961, 1984). The other SIX cases look like a roll-call of historic El Niño events since 1950: 1957-58,'65-66, '72-73, '82-83, '86-88, and '97-98."

He continues:  "Not only does this confirm the increased odds of an El Niño in 2014 (first pointed out four months ago on this wepage), it also translates into higher odds for a moderate-to-strong El Niño" 


Using 1963, 68, 86, 91, 94, 2002 and 2006 as the best fit years taking into account the MEI and early stages of a MODERATE EL NINO, the summer temperatures versus average look like this:

If we include the years during the early stages of the STRONG EL NINO events of 1982 and 1997 weighting them the same along with the other years above, we get this:

 If the STRONG EL NINO years are weighted DOUBLE, we get this:  COOLER SUMMER!

The bottom line is this summer's temperature outlook will be determined heavily on how strong this El Nino becomes. Final SUMMER OUTLOOK will be broadcast in early May on WJW FOX 8. 

Monday, April 07, 2014

Spring Rains, Wet Snow Next Week?

I'm back from a few days off last week bringing in more rain!  At least its not snow....not yet anyway. Here are the current radar images for northern Ohio and the Ohio Valley. CLICK HERE for the current RADAR LOOP.

Rainfall will be between 1/2 and 3/4" with locally heavier amounts by Tuesday mid morning.

It should come as no surprise that the long range outlook for next week is STILL showing temperatures cold enough for wet snow. Notice how next week's cold is very similar to the last time we had 2 or more inches of snow in mid April.

Thursday, April 03, 2014

Heavy Rain: Current Radar, Rainfall Estimates, NEXT WEEK'S COLD

The cold, steady rains continue. Current radar loops close up over northern Ohio and around the Great Lakes along with rainfall estimates tell the story. Remember that over a week ago, I hinted at a well below normal period during the second week of April. Since this is late in the season, colder periods don't typically last more than a few days. This one next should follow that rule of thumb pretty well. However, it might get cold enough for at the very least, melting snow!


Brief period of cold...wet snow late Tuesday into early Wednesday. Temperatures will rebound nicely by Thursday.

Graphic: Weatherbell