Friday, June 15, 2012

History of 90 Degrees Days In Cleveland

How many 90 degree days have we had in Cleveland since 1980?

What is the 90 degree temperature trend per decade over the last century in Cleveland?

What month are we more likely to see the most 90 degree days?

Wednesday, June 13, 2012

A Look at June...The Outlook for July

Will July be cooler or warmer than average?  That's the $64,000 question.

Summer or winter outlooks are the most sought after of forecasts--the 8day forecast is a close second.  Face it.  People love to look into the future.  What is the first think we think of when planning an outdoor wedding reception or graduation party? The weather.  We search and search for that elusive piece of weather information that might tip the scale in favor of ordering a tent.

In the weeks and months leading up to the party, we become manic.  The seeking of that long range outlook  is tantamount to investigating what's in Area 51. We are attracted to it because we see it as a diamond in the rough.  Yet in reality, any long range outlook, much like Area 51 on a map is a gray area filled with fuzziness. 

When people call or email questions about the weather for specific days 3 or 4 weeks out, they don't care that its beyond our ability to give them specifics.  They just want weather information to hold onto even if it might be that "gray area filled with fuzziness". 

One thing to always keep in mind about "Long Range Outlooks" is that they are TOTALLY different than daily forecasts both in how they are created and the parameters used in their creation.  We can't look at the weather in Chicago yesterday and develop a long range outlook for the month ahead.  But we can study an evolving La Nina or El Nino, for example, to find linkages to overall shifts in our weather pattern that ultimately affect our weather in Northern Ohio.  For example:  Does a developing La Nina in the Pacific lead to a pattern conducive to cooler temperatures? Or does an El Nino lead to more rainfall in Ohio? We are not after specific weather conditions for specific days but a general outlook for weeks and months in the future based upon generalized patterns.  If you are looking for the high temperature 24 days from now, the Long Range Outlook isn't designed for that.

June is half over.  Conditions have rapidly dried out; temperatures through June 15th have been near normal.  Based on what we see now, what general pattern might we see in July?

Look at the disjointed nature of the upper level winds. Each one of these "buckles" in the flow allow a trough or front to move through bringing small chances of rain followed by a temporary cool down. Notice no ridge of heat...yet. 

The HEAT RIDGE across the eastern US from last year and 2010 hasn't developed.   The Sonoran ridge (SW ridge) has been weak. The Bermuda High is still out in the Atlantic.  What lies in the middle are temporary shots of cooler air. 

This dry and warm stretch through Fathers' Day weekend has been the exception.  Here, the ridge out west shifts east boosting temperatures. The red dot is OHIO.

Beyond 7 days, we need a different set of tools to determine the pattern.  Normally, computer projections lose their skill further out in time. In an effort to diminish this effect, we can run the computer projection multiple times with different initial conditions. After, say 20 runs, an ensemble forecast is created by taking the average of all 20 runs.  This ensemble smooths out the chaotic atmospheric elements making a long range projections more accurate.  Its not perfect but its a Godsend when making long range outlooks.

I've hinted at a "cool down" the last 7+ days of June.  Why?  Look at the ensemble for June 28th.  Heat shifts back west. The Bermuda high stays out at sea.  In between lies cooler and hopefully unsettled weather (we need rain!)

La Nina is gone. El Nino is showing signs of returning in the fall.  Since no large scale drivers are in place like last summer or 2010, we utilize other smaller scale, faster moving signals that originate in the Indian Ocean and move into the central Pacific Ocean.  These faster moving disturbances can create a short-lived La Nina or El Nino signal which can dramatically alter the pattern across the US.  Many long range forecasters linked these disturbances  to the heat we had in late May.  It seems that this "Indian Ocean disturbance" MJO will once again be the driver of our pattern into early July.

Based on the July years that best match the conditions this year, we came up with this:

So expect another long stretch or two with 5-7 days of heat in July with another "cooler" reprieve.  Heat will come and go.  Overall, July seems to average near normal over the 30 day period.

Let's see if this outlook hold true...

Monday, June 11, 2012

The Basics of the Early Universe

I have been working on a study of some Cleveland climate data recently. Compiling the data was very time consuming.  Patience...patience.  The results will come later on this week.

In the meantime, take a listen to this presentation about the universe from Sean Carroll, theoretical physicist at Caltech. He describes the early universe in very easy-to-understand terms. The study of the early universe and the reason why EVERYTHING around us behaves the way it does has always captured my attention. It makes me think in many dimensions outside the box.

Fortunately, youtube offers a ton of information tightly compacted in video form that only takes 10 or 15 minutes to watch.