Wednesday, June 22, 2016

Severe Event Likely Tonight. How Do I Convey The Message?

A significant severe weather event is likely across the Ohio Valley tonight. The Storm Prediction Center has western Ohio under a moderate risk, a slight risk for the center of northern Ohio overnight. We are only under a moderate risk a few times a year.  So far, no tornado warnings have been issued for any county in northern Ohio, a rarity this late into June. This is a situation that we need to take seriously.

Radar shows the first of two storm clusters passing just south of northern Ohio. Notice the movement: Northwest to Southeast on the eastern edge of the central US ridge.

At a speaking engagement recently, I surveyed the group of around a hundred people what word they think of when I say the words severe when referring to the weather. The majority of them said tornado. Yet statistically, roughly 10% of severe storms produce a tornado. This is why you will rarely hear me use the word severe unless the situation absolutely warrants it. The word severe is very powerful and conjures up powerful imagery and perceptions. Weather situations like the one tonight (June 23, 2016) reminds me of the psychology behind our weather forecasts.

I'd like to say that I make a forecast with a cold, rational eye but I don't. I take into account how people with react to EACH WORD knowing that most people will react with their preconceived weather notions they've developed over time. Viewers hear the word severe and they think tornado. They panic and fear the worse even if the cold hard facts say otherwise. Its hard to reverse that mindset. I learned that real quick after my first major lake effect event twenty years ago.

If I could make a poster with bullet points for meteorologists, it would list these five at the top

*  Public perception is very powerful

*  We need to be better communicators of information. Quality of the information is better than clicks or social media engagement

*  Choice of words is of the utmost importance in conveying severity of any weather situation

*  For the public, risk is personal and evokes powerful imagery.  Mass media is for the masses.  Yet the masses in this era of smartphone weather apps want personal forecasts. Huge conundrum.

*  Too much emphasis on uncertainty breeds confusion and inaction. (I am hugely guilty of this as a technical weather geek) We need to find a delicate balance between voicing uncertainty and sticking to a forecast without blowing the event out of proportion.

Friday, June 10, 2016

Developing La Nina Is Old News!

Many meteorologists including myself have written about the state of the winter El Nino and the strong probability that ENSO would transition to an infant La Nina in spring/summer of 2017 for a while now.  Main news sources give the impression at this transition out of El Nino as something new.  I tweeted a preliminary La Nina outlook based on CPC analogs BACK IN NOVEMBER!

Recently, NOAA stated in their newest bulletin, very accurately, that El Nino was finished as of June 9th. These transitions don't occur instantly. The transition away from El Nino toward La Nina has been ongoing for months.

The region used in determining the state of the equatorial Pacific is the ENSO 3.4 region.

All Nino regions (especially the key Nino 3.4 region) temperatures have been falling since the start of the year.

This animation showing the ocean temperatures vs normal values show this perfectly. See the cooler water on the right side (east).

A larger spherical look at the ocean temperatures show the transition even better starting in January. The last image is what the mature La Nina looked like in January of 1999.

According Bob Hensen at Weather Underground, a recent study found that about a 1/3 of first year La Nina events returned of persisted for a second year. This behavior seems to be more frequent over the last 150 years.  It is possible that La Nina could linger into 2018.

It takes months for the effects of any ENSO state (El Nino, neutral or La Nina) to be reflected in the atmosphere. So its very difficult to predict at this time what the winter will be like for specific locations. But we can perform some basic albeit general statistical comparisons between snowfall and La Nina.

Using the ERSSTv4 ocean temperature dataset, a list of La Nina strengths can be determined. Hat tip to Eric Webb.

Based on these years and rankings, I matched up our Cleveland snowfall for these La Nina years. Here is what I found.  The majority of these years had ABOVE NORMAL SNOWFALL in Cleveland!

This is no guarantee of above normal snowfall during the winter of 2016-17 as there are other factors yet to be determined. 

Last year, I posted my thoughts on the upcoming winter (2015-16) around Labor Day. Expect some more detailed thoughts on the effects of La Nina on the upcoming winter of 2016-17 around the same time this year.  Until then, let's enjoy summer!

Thursday, June 02, 2016

Is It Accurate to Say "It's Cleveland" When Talking About Our Weather?

Good morning everyone. This is a pet peeve of mine so bare with me:  

It's highly inaccurate to say "It's Cleveland" when making a GENERIC reference to our overall NE Ohio weather. I know I've upset many by saying this. We've been indoctrinated with this for decades and generations myself included. This phrase really only applies to winter conditions such as lake effect snow events or a strong lake breeze (especially in spring) which don't happen often. Most times (see image below showing the 6 week changes since early May) the changes are felt over a multi-state area! These regional changes don't originate here in northern Ohio nor are they religated to just northern Ohio. Again, the only exceptions that are strictly local in nature are Lake Effect snow events and lake breezes.

Tuesday, May 24, 2016

Memorial Day Temperatures Doing A Complete 180!

Back on May 10th, I posted this long range outlook showing that our confidence of warm finish to the month of May was very high. This was my thinking at the time.

The first 23 days of May were cool not only in Cleveland and northern Ohio but across 85% of the US.

The final 8 days will feel summer like across a 15 to 20 state area.

Who says realistic long range outlooks aren't possible?

Friday, May 20, 2016

The Weather Cast

Some days weather casts flow with metronomic ease. Each segment evolves with seemless precision incorporating sprinkles of down-to-earth science, flawless grammar resulting into an easy to understand message. It permeates the air with the richness of a chocolate cake. Other days it's like driving a dump truck through a nitroglycerin factory with no chance of rescue.  I've blown up a bunch of factories.

Monday, May 16, 2016

How Rare is May Snow in Cleveland?

Sunday marked only the 12th time since the late 1800s we have had measurable snow in May.  The latest report of snow at a National Weather Service reporting station in Cleveland was May 27, 1907 when we had a trace. Keep in mind that weather reports were recorded at different location around downtown Cleveland from 1870 through the 1930s.  Readings started at Hopkins Airport southwest of the city in the mid 1920s.  

Snow cover in Middlefield, Ohio
It wasn't until the late 1930s when records became consistent and searchable. Officially, we only had a trace at Hopkins Sunday.  850 mB temps were between -5 and -7 early Sunday morning with surface tempertures in the mid to upper 30s.   The rare instances of May snowfall is list below. 

All May snowfall instances recorded at Hopkins Airport (post 1938) and downtown Cleveland 1870 to the late 1930s

Monday, May 09, 2016

Are These Big Spring Temperature Changes Something New?

Many times throughout this spring people have commented to me how they never remember wild swings in temperature in northern Ohio quite like what we've experienced this year.  Rather than assume a specific conclusion, I went back and found the high temperatures for every day since 1975 from March 1st through April 15th and again for April 16th through May 31st. I highlighted each instanced where the day-to-day high temperature change was greater than 20 degrees either. In other words, if the high temperature one day was say 38 and the high temperature the following day was 60, that counted. If the high temperature fell from 75 to 52, that would also count.  Here is what I found.

The number of occurrences haven't varied a lot over the last 40 years between March 1st and mid April. I thought the numbers would have been higher since the late 1990s.

Historically, large temperature fluctuations after April 15th don't occur as often due to the lack of residual cold air left over from winter. So far this year (2016) we haven't had an occurrence since April 15th.

What I found interesting is that the occurrences of day-to-day high temperature drops of 30 degrees is significantly higher than temperature jumps of 30 degrees especially before April 15th.

As much as perceive these fluctuations to be a new thing here in northern Ohio, it is quiet common in early spring and has been for at least 40 years. This is another classic example of the Recency Effect as work.  That is we overly weight in our minds more recent events with greater significance and quickly dismiss events further back in time. Note that these conclusions are derived ONLY from Cleveland temperature data.

Friday, May 06, 2016

How big is the largest Alberta Fire?

The Fort McMurray fire as of Thursday May 5th is around 85,000 hectares or 210,000 acres! These comparison to big cities around North America are staggering. Images courtesy Macleans.

The Omega Block in the middle of North America kept central Canada dry accelerating an already dry region from this past winter. Well above normal temperatures surged north.

Omega Block (looks like a double)

More heat this weekend. Some relief is on the way late this weekend as the temperatures will fall back into the 50s.

Saturday high temperatures

Rainfall Sunday into early Tuesday

Cooler air Sunday

Thursday, April 28, 2016

The BIG Winter Recap - Part II - Northern Ohio (Summer Thoughts)

The last "cold" morning in Ashtabula this winter
The strongest El Nino since 1997-98 and a stable arctic tempered the cold of the last two winters. Temperatures across northern Ohio were well above normal with below normal snowfall similar to the winters of 2011-12, 2001-02, 1997-98 and 1982-83. Two of those three were strong El Nino winters.  Our outlook last fall was for above normal temperatures and slightly below normal snowfall.

Above normal temperatures were more extensive across the US. According to the NCDC, global ocean temperatures were at record levels.  (See PART I of my winter recap for other drivers)

Given the panhandle storm track forecast back in September/October, we were very confident that we would get hit with at least ONE big general snowfall which would boost snow totals into the 50-55 inch range. Overall, the heavy snowfalls stayed south and east of northern Ohio which kept our totals even lower. Those big snows came VERY close to northern Ohio!


How does this winter compare to the last two cold winters? How does this compare to the similar winter of 2011-12?  Here are the final tallies.  The same metrics used in last winter's winter recap were used this year to keep everything consistent.

Everyone thought winter was over until our early April snowfall. The April snowfall was almost 24% of the entire winter total; second highest ever!

 Lake Erie Ice Cover reached a peak of 75% for a few days in mid February.

 That's a bit misleading as the peak ice cover went from 3% to 79% in 3 days! In 11 days, it dropped to ZERO in a week and a half.  GRAPH BELOW

Ice cover was thicker and more widespread for much longer last winter.  For comparison, last year it took 28 days to reach 94% and it stayed above 90% for 47 days. Whereas in the winter of 2011-12 (similar to this winter--see above), ice cover reached 13%, only 6 days above 10%.  

Ice cover during the last big El Nino back in 1997-98 was even LOWER than this year. A whopping 8.4% maximum!

Will the leftover winter El Nino play a role in our summer temperatures and precipitation?  Will El Nino continue to weaken?  If so, how will this effect the summer and upcoming autumn? Will severe weather occur more frequently?  Summer Outlook coming up in a few days!  Check out