Tuesday, April 20, 2021

Late April Snowfall: How Rare is this?

Yes, it's April 20 and we are talking about accumulating snow!

Sure we've seen late season snow before. It snowed in mid-April in 2019.

...and it snowed in May 2016 (under an inch).

In fact 16 of the last 20 years has featured measurable snowfall after the first day of spring. Over the last 30 years April has featured snowfall almost half of the time. But snow that need shoveled after April 20 is something else entirely.

Below is a calendar of each day starting on March 20 showing the snowfalls for each day. Notice how the frequency of snow drops significantly once we make it through the first 10 days of April. Interestingly we've only had 3 snow events greater than 2" after April 20th. Two of those occurred in 2005. (I remember driving home from work during that big snow on the 24th).  The other one was on May 6, 1974.  We've had snow in May but never more than 2 inches.

The late April snow in 2005 was historic for northern Ohio.  Look at the similarities between this year's pattern and 2005. Position of storm center is close.  2005 was much deeper.

Bigtime cold across the Great Lakes and New England (April 2005)

Much of northern Ohio saw more than a foot of snow that year in late April

This time the overall pattern was showing signs of stronger weather systems by the 3rd week of April (shades of blue).   My tweet from April 5th below.

The cold was building a week ago in central Canada as this temperature animation below shows. This loop is from April 15 to April 29.  Not much warmth here.

Snowfall accumulation is much different this time of year due to warmer ground and road surface temperatures.  These numbers are mainly for grassy surfaces.  Snowfall on roads and sidewalks will end up being under these levels. Sun angle is much higher so any sunshine will accelerate snow melt Wednesday and Thursday. 

Snowfall forecast could mark only the 4th time we've had more than 2" of snow this late in the season.

By the way, this snow doesn't give us any indication of what the rest of spring and summer will be like. More on the summer outlook in the weeks ahead. 

Thursday, March 18, 2021

Who Really Supplies The Power: The Pitcher or The Hitter?

 I always grew up hearing this from coaches when a power pitcher was on the mound:

"He'll supply the power. Just make contact."

It seemed to make sense. The faster the ball hits the bat the further it will travel after impact.  Except the science says otherwise.

The formula to determine the speed at which the ball rebounds off the bat is:

                                                           vexit = q vpitch + (1 + q) vbat


(1 + ea) * SWING SPEED

Where vexit  is the ball exit velocity, vpitch is the velocity of the pitched ball and is the vbat  speed of the bat.  "q" is COLLISION EFFICIENCY

Collision efficiencyvalue is between 1.0 and 2.0 depending on the squareness  of the hit. A well hit ball with a wood bat on the sweetspot gives a value of 2.0.   A detailed explanation of COLLISION EFFICIENCY is in this paper.  I used a value of 1.5 for q with graphs below.

So what does this formula tell us?  It shows mathematically that the batter's swing speed is 6 times more important than the pitch speed in creating higher exit velocity!

Graphs below show the exit velocities for 5 several bat speeds (60, 65,70,75,80 mph) as pitch speed increases from 65 to 100 mph. 

Notice how flat the exit velocity increases are for each bat speed. While there is an increase as the pitch speeds increase (pitch speed does have an influence) it's not a large one.

When we increase both the pitch speed AND the bat speed, the exit velocity increases more sharply.

So for a pitch speed of 65 mph and a relatively show bat speed of 60 mph, the exit velocity after a decently hit ball would be around 79 mph. An increase the pitch speed to 85-90 mph with a commensurate increase in bat speed to 70-75 mph would yield an exit velocity above 95 mph. Similarly a bat swung at 80 mph making contact with a 95 mph pitch would cause the ball to leave the bat at 105+ mph.  

Bat speed not pitch speed supplies most of the power!

Thursday, March 04, 2021

What Locations See The Greatest Day-to-Day High Temperature Changes?

We often think that our location has the greatest weather changes. Often times that's true. I can count the numbers of times when people say "That's Ohio weather. Wait 5 minutes and it'll change." The perceptions are powerful. I wrote about this a few years back which you can read HERE. But when we look at the entire middle of the country, the locations that see the greatest frequency of day-to-day temperature change might surprise you.

How did I figure this out? I downloaded the high temperatures for each day for 20 cities over the last 50 years. (I would have downloaded further back in time and more cities but I ran out of time and computer speed). I found the day-to-day temperature differences and counted up the instances when it was more than 20 degrees. Finally I tabulated the totals for each month and graphed them below.

The central of the US features the largest day-to-day temperature swings especially in March and April. Eastern Nebraska, northeastern Kansas, northwestern Missouri and portions of Iowa and southern South Dakota.

Also notice the pockets of higher frequency across Ohio and western Pennsylvania in March. Another localized pocket is located over northern Illinois and portions of Wisconsin in May and June. 

When you look at the biggest changes between daily high temperature and low temperatures, the high frequency area shifts to the panhandle of Texas and Oklahoma.

Image Courtesy: NWS Amarillo (Chris Kimble)

What is the largest temperature difference between high temperatures and low temperatures between days in Cleveland?  Lows were close to ZERO the morning of March 8, 1986. By the afternoon of March 9th, the temperature was in the lower 60s...almost 70 degrees by the 10th!

Wednesday, February 24, 2021

Unbelievable Great Lakes Ice Time lapse

One of the most impressive time lapses I've seen in a long time. This is from WGN-TV Hancock camera earlier this week (February 21). Look how quickly the ice opens up over Lake Michigan as the winds shift and the temperatures rise. If this doesn't cause you to rethink walking on the ice I don't know what will.

Cracks in the ice are VERY common especially this time of year. Fluctuations in air temperature, wind direction and intensity drive the shifting ice making it more unstable.

Ice coverage across the Great Lakes have reached their peak and are now falling.

LAKE SUPERIOR:   51% on Feb 19th

LAKE MICHIGAN:  335 on Feb 18th

LAKE HURON:     48%  on Feb 20th
LAKE ERIE:           86% on Feb 20th
LAKE ONTARIO:  21% on Feb 18th 

Lake Erie, the shallowest of the lakes is showing significant ice breakup.






The ice movement forecast through early next week.

Compare this year to the last 2 years:

I checked the years since 2000 that had at least 50% ice coverage on March 1st. The average date where we drop to under 25% ice cover is during the last week of March. This is directly connected to the air temperatures. Based on the long range outlook through the first 7-10 days of March, the ice loss should be gradual.

Tuesday, February 16, 2021

Why Didn't Monday's Snowfall Pan Out?

My cardinal rule is NEVER post snowfall numbers further out than 48 hours. Way too much uncertainty especially with panhandle systems. Nothing exemplifies this prime directive more than what happened over the last 24 hours.  Let's set the stage.

Willard, Ohio - Tuesday Morning 2-16-2021

Winter storm watches then warnings were issued Sunday across more than 600,000 square miles of the US.  The largest single winter warning map since 2011.

The future radar track (HRRR) took the bulk of the snow through Ohio over a 10-12 hour period. Now watch the mixed precipitation area (orange/purple/pink) try to inch into east central Ohio.  A common occurrence with panhandle storm systems. 

This is what I mentioned during the Monday morning 40+ weather segments as a REAL possibility given the conditions. At the time did I think it would reduce the snowfall forecast in half? Nope.  So what happened? 

I captured the Monday model projections from 1am,7am, 1pm and 7pm time periods for comparison on how the event evolved over time.

Model output

Notice how the LOW made some subtle shifts. Originally it was east of Columbus with the early Monday morning projection. It started to shift more north the south again with the 3rd and 4th projection (see below).

These small scale shifts gave us some indication that the warmer air was influencing the movement. The temperatures at 5000 feet was WARMER than the air closer to the surface in eastern/SE Ohio.

The total liquid precipitation projected earlier in the day was substantial and widespread.

It wasn't until early Monday evening where the precipitation projection went down. (See below and right)

The precipitation type was always in question across extreme southern counties. Bottom graphic below shows a last-minute shift with sleet/freezing rain north and a westward shift in the heavier snow.

The future radar also depicted the same late afternoon/early evening changes to the position of the wintery mix & heavy snow.

Snowfall projections were consistent through noon/early afternoon...

As the warm air became more influential, the snowfall output shifted into NW Ohio and was greatly reduced south of Akron.

Our initial snowfall forecast issued Monday morning based on little warm air influence

The snowfall totals as of 10am Tuesday morning from the NWS in Cleveland. 7-12" totals from western Huron/Erie counties into NW Ohio.

Sandusky, Ohio