Tornado Warnings - NWS Cleveland - Date of First Issuance

 

Northern Ohio Severe Weather Recap. ONE TORNADO CONFIRMED

A pretty big weather day yesterday across northern Ohio. Many severe storms with heavy rainfall (2-5"), 1" hail reported & tornado warnings. 

Many people have complained about our "wall-to-wall" coverage saying that nothing was happening and it wasn't worth it. "No tornadoes on the ground so what is the point of coverage like this?" a few said via Facebook and Twitter.  While its easy to lump this event in with all of the others, this round of severe storm was very different than other severe weather events we've had in the recent past in northern Ohio. Why? First, many of the severe cells had the classic hook echo characteristic indicating strong counter clockwise winds which often indicate a tornado. Thankfully, only ONE TORNADO was confirmed in Lorain County. I thought we'd end up with 4 or 5 easily.

Secondly, many cells also had strong changes in wind direction embedded within them. By using the "Velocity Scan", we can determine which cells have rotational signatures by recognizing those small scale wind direction changes. Green colors mean wind moving toward the radar. Red colors mean wind is moving away. Notice the abrupt change and the implied rotation.

For these reasons, the National Weather Service issued tornado warnings. As a public service, it is mandatory to inform the public of the tornado warnings. Given the numerous storms, we needed to break into programming to cover this event BIG TIME! 

For those of you who claim that more tornado warnings are being issued for northern Ohio, that's not the case. After doing some exhausting research compiling tornado warning history, I found that the issuance of tornado warnings at the National Weather Service office in Cleveland, Ohio (our home office) is trending lower since the early 1990s. Also, the percentage of tornado warnings that result in actual tornadoes here in northern Ohio during the same period is comparable to the national average.

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As we recap yesterday's severe weather, its a good idea to review what constitutes a severe thunderstorm as defined by the National Weather Service.

Most storms NEVER reach severe limits. A very small number of severe storms actually produce a tornado. That's comforting news for all of us. That said, the mere mention of the word "severe" has extreme connotations. Many people believe that the word "severe" means "tornado". Nothing could be further from the truth. Here are the tornado facts and figures that I hope set the record straight.

* 5% of storms are severe. Only 1% of storms produce tornadoes

* Tornado warnings are issued for about 75% of all tornadoes

* In 2007, the National Weather Service started to issue warnings on a more local level versus on a county basis. These "polygons" localize the threat inside a specific part of a county.

* Tornadoes occur over a wide spectrum of strengths, sizes, and lifetimes.  Of the 800–1400 tornadoes reported in the United States each year, about 86% can be characterized as weak, 13% as strong, and 1% as violent.  

* In general, weak tornadoes (86%) have lifetimes less than 10 min, widths around 100 m (yards) and paths less than 1.6 km (1 mile) in length.  National Weather Service radars can complete ONE SCAN every 4 to 6 minutes! 

* Typical tornadic wind speeds are on the order 110 mph.   

* The average “lead time” for tornado warnings was less than 5 min in the late 1980s. By the late 1990s, lead time was up to 10 minutes; 13 minutes today (2014)

* National Weather Service forecasters provided a 24-minute lead time for tornado warnings in Joplin, Missouri back in 2011, almost TWICE the national average. 

* According to one study in 1978, there was a 22% probability of tornado detection with a 3 minute warning lead time. By 1998, the probability had jumped to 65%! 

Crying Wolf? I Think Not: Severe Weather Definitions

It never fails.

During and after each and every severe weather event, there are a few people that selfishly say "Where are the storms? You all said we'd have severe weather. All we're getting is wind and some rain. You weather people never get it right!" Nothing gets me more fired up more than idiotic comments like this. Tell this to the families who lost loved ones in this house in Nashville, Illinois.

My blood pressure is climbing just writing this......errrrrr!

I have written many times about how our perceptions and preconceived notions tend to govern our thoughts especially when events occur that seem to support and reinforce our biased notions. I try to tell these individuals that severe weather forecasts are approximations. That's why tornado watches are as large as a state not a city. 

People will think the way they want to think regardless of how much data you present them to the contrary.  How often have our biases surfaced during election years (economic issues), in our day-to-day lives perhaps when we interact with others?  See my posts about cognitive biases and  cognitive dissonance relating it to weather HERE and HERE. Note the parts in red print if you want the Cliffs Notes version.

Anyway, maybe these basic severe weather definitions will clarify some of these misconceptions and perceptions about severe weather. Bottom line is this: When the Storm Prediction Center has a region in a MODERATE to HIGH RISK for severe weather, bad things will happen. This is not something to be taken lightly.

 

Hurricane Projections Getting Interesting

So far this year, hurricane season has been very quiet. A few storms developed in the central Atlantic. Those storms didn't last long.  But notice the storm track. The steering currents have curved each storm to the northeast.

The focus of attention in the weeks ahead will be over the Caribbean and Gulf of Mexico. While no storm (as of this writing--August 18th) has developed yet, all of the computer projections show rapid development of one area of storms into a formidable hurricane late next week

We look at 3 distinct projections.  The GFS model, the Canadian model and the European Model.

The GFS (American) Model by next Saturday the 28th show a hurricane near Florida

The Canadian Model shows the same hurricane near the Carolina coast

The European Model shows it near Florida

Whether or not this actual verifies remains to be seen. The bottom line is that the computer are seeing the tropics becoming very active very soon and very fast. Based on a multitude of factors, I believe that the US will be hit with a hurricane at some point this season. Stay tuned!

Local Flooding in Ohio...Technical Issues This Morning

Today was a very busy day on multiple fronts.  First shortly after the start of the 4:30AM show, the news server went down and went down hard.  Without going into too many technical details, you only need to know that we had no video, no audio, no stories, no flashy animations.  Basically, the anchors had to read the news on camera for several hours. In between stories, they dutifully filled the space with clever banter sometimes hinting at the difficulties of the morning.  Needless to say, it was an exercise in mental toughness not only for the anchors but for the producers and countless other behind-the-scenes people who painstakingly found ways to get the long show on the air.  Of course, inclement weather such as flooding and storms make the show a bit easier to produce.  When all else fails or you run out of options, toss it to the weatherguy, right?  Today though, it was out of necessity and it was actually necessary.  Bottom line, all worked out fine.  The shows went off surprisingly smooth.  As of this writing, the server is almost at 100%...maybe not.

Back to the flooding and storms.  A cluster of storms/heavy rain began to develop over the lake around 11PM.  By 2PM, it had dropped an inch of rain in Cleveland.  By 9AM, more than 6 inches of rain fell in some areas in southern Summit county, northern Stark county. A few reports near Strongsville also reported around 6 inches.

The lightning around 4:30AM was equally as impressive

Temps are climbing with another 90 possible.....

Why the increase in SEVERE WEATHER this spring?

UPDATE 4/28/2011:

Yesterday will go down as the worst tornado outbreak since the Super Outbreak in 1974 which included the Xenia tornado in Southwest Ohio.  Here is roofcam video of a mile-wide tornado that went through Tuscaloosa, Albama.



The final tornado and fatality numbers will be adjusted as the official survey the damage. Here is a look at the storm reports. The tornado reports are highlighted in red.  More than 160 IN JUST ONE DAY.

Great video of a storm chase/tornado in North Carolina from earlier in the month

Why the sudden increase in severe weather? Is it Global Climate Change?  Is it natural climate shifts?  Probably a mixture of both...The driver we will focus on is the role the Pacific Ocean plays inour weather patterns here in Northern Ohio.

The ocean temperatures go through cycles warm and cold, wet to east. This year, the ocean water temperatures are warm west and cold east near South America. This is called LA NINA. Here is an animation of the current ocean temperatures compared to normal. Notice the blue shades east.

This cooling east and warming west causes storms to develop west near Australia.

The ups and downs in the atmosphere causes the jet stream to change causing it to dive into the Great Lakes and into Ohio. Notice the "wet" green area in the Ohio Valley and the shades of red in the deep south.

Our rainfall in Northeastern Ohio has been well above normal this month.

Last year (2010), La Nina hadn't kicked in.  While we did have tornadoes in Ohio (the first graphic below showing locations and intensities last year), the country had far less tornadoes overall compared to 2008; another LA NINA YEAR!

"LA NINA" springs tend to feature greater than normal numbers of tornadoes.  The graph below shows the frequency of F4 and F5 tornadoes compared to LA NINA and EL NINO years. The LA NINA numbers are shown in the red.

Can we expect tornadic weather here in Cleveland and Northeastern Ohio this spring and summer?  Eventually yes.

Here is a loop of the storm reports for the first two weeks of June 2008, a year similar to 2011 when comparing severe weather. Notice the severe storms are further north than the recent outbreaks.

So as the temperatures rise, expect our severe weather chances to increase across Ohio into June and July

Stay Tuned!!!

Strongest Great Lakes Storm in Years!

Late October and Early November are considered a second severe weather period after April, May and June.  This is due to the leftover warmth of the summer still lingering across the south clashing with the first real pushes of winter air across the upper midwest.  What lies in between both air masses is usually a strong cold front and a deepening low which produces bursts of high wind and often times, a line of severe storms.

Tuesday, October 26th, a deepening low over the western Great Lakes was evolving into a severe weather producing machine.  Note the "L" at the top of the map taking up 50% of the country.  But this storm is different.  The pressure is lower than ANY great lakes storm since 1978 acording to the National Weather Service office in Chicago

Moisture (warmer colors) feeding into the storm aided in the development of severe storms.

HIGH WIND WATCHES and WARNINGS shown with tan watch boxes stretched from Montana to eastern Tennessee.

Early morning tornado watch boxes were issued from Chicago, south to St. Louis and east to Cleveland. 

Northern Ohio was under a "high risk" for severe weather for the first time in years.  This designation is typically reserved for tornadic weather in tornado alley, not Ohio.

Expect power outages through early Wednesday across northeastern Ohio through early Wednesday. 

Hurricane Katrina - 5 Years Ago

Five years goes by very fast even when one of the most devastating natural disasters is concerned.  It was on that Sunday back in 2005 when Hurricane Katrina made landfall over New Orleans. It took a similar track to Hurricane Camille took back in 1969 over New Orleans.  This time, the damage was far more significant; the cleanup and rebuilding continues to this day.

Katrina made landfall over the Florida Keys days before as a tropical storm.

It weakened over Florida and quickly redeveloped into a major hurricane mainly due to the Loop Current, a current of warm water between the Yukatan Peninsula and Cuba.  The same current that was responsible for the steering of the 2010 Oil Spill.  The red color shows the Loop Current with Katrina's track over the top.

Katrina as a major hurricane shortly after intensifying in The Loop Current

Katrina's track from the Florida Keys to its New Orleans landfall is shown in this satellite photo blending several images with the track superimposed.

Katrina was a Category 5 shortly before landfall.  It weakened to a strong Category 3 as it made landfall with at least 80% of the city experiencing Category 1 or 2 level sustained winds. New Orleans was hit with winds of 125 miles per hour.  Below is a closeup high resolution satellite photo of the eye before landfall.

The eye over New Orleans

This graphic shows the level of the city compared to the level of the Gulf of Mexico.  You can understand  why 80% of the city was under water.

It proceeded inland with winds rapidly decreasing as shown below.

Hurricane Katrina's track headed north through Tennessee, Kentucky and Ohio as a depression with heavy rains.

The total rainfall from Katrina was incredible across the south. 8 to 10 inches of rain fell across the eastern half of the state with a local report of 15 inches near the Mississippi border.  Amounts of 1 to 2 inches for us in Cleveland were common several days later.

The rainfall swath was similar to the rainfall areas created by the track of Hurricane Camille in 1969.

High winds were reported as far north as Detroit and Cleveland  of over 50 miles per hour.

Its Official: New Hailstone Record

Imagine this mammoth hailstone falling in Cleveland?  Here is the official story.  Credit:  The Weather Channel and the Associated Press
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A hailstone found at Vivian, SD Friday night has now been determined to be the record largest U.S. hailstone by weight and diameter.  This 8-inch diameter stone, pictured above, weighed in at an incredible 1.9375 pounds.

The old record heaviest U.S. hailstone was a 1.67-pound monster in Coffeyville, KS on Sep. 3, 1970.  The old official largest diameter hailstone, measuring 7 inches in diameter, was recovered in Aurora, NE on June 22, 2003.

The Aurora, NE hailstone still holds the U.S. record for circumference, however, with a circumference of 18.75 inches.  The Vivian, SD hailstone fell a quarter-inch short (18.5") of that standard.

Leslie Scott, who found the record hailstone, said it lost about 3 inches because he was without electricity for several hours after the storm. NWS meteorologists told him to put it in a sealed plastic bag and stop opening the freezer door to show it to people.


"If I knew it might be a record, I would have looked for a bigger one, " he said. "There was lots of bigger ones than the one I got. My mother seen one as big as a football, she claims."

Hail from the storm led to at least five reports of injuries on Interstate 90, when hailstones crashed through vehicle windshields.  All 55 homes in the town of Vivian were damaged.  One mobile home's roof was punctured 25 times!

"I've got 19 holes in my roof.  Three of them go all the way through my ceiling," said Lisa Patrick, who lives in Vivian.

SOME HAIL FACTS

Large hail is a fact of life in America's heartland. Each spring and summer, we marvel at reports of hailstones the size of baseballs, softballs, or even grapefruit from intense supercell thunderstorms roaming the Plains. Some storm chasers wear helmets when documenting supercell thunderstorms.

TWC Severe Weather Expert, Dr. Greg Forbes (Find him on Facebook ), notes that there have been six other instances of 8-inch-diameter hail in the U.S. since 1950, including a stone shaped like a cigar-box in Izard County, AR on June 19, 1970.


Hailstones this large falling at speeds up to around 100 mph, surprisingly, don't often result in fatalities. This may be due to the relative infrequency of very large hailstones (say, baseball-size or larger) over densely-populated areas.

According to Dr. Forbes, there have been only six U.S. fatalities due to hail alone, dating back to the 1700s. The most recent death was a pizza deliveryman in Ft. Worth, TX on Mar. 28, 2000.

The world's hail capital may, in fact, be in northern India and Bangladesh. A single hailstorm killed 246 people in India on April 30, 1888. More recently, 92 were killed in Bangladesh by an April, 1986 hailstorm.  According to "Extreme Weather", by Christopher Burt, India and Bangladesh witness 10-15 days with hail each year, on average.

The world's heaviest authenticated hailstone, according to Burt, weighing in a 2.25 pounds, pelted Bangladesh in the aforementioned April, 1986 deadly hailstorm.  Its diameter was not recorded.

Unofficially, a hailstone weighing an incredible 4.18 pounds was said to have fallen in Kazakhstan in 1959.  In August, 1958, a 2.14 pound hailstone was documented in Strasbourg, France. 

Newspaper Scans After The Cleveland Tornado