US Temperatures: April 2012 vs April 2013

What a difference a year makes! WELL BELOW NORMAL APRIL ACROSS THE US!

   

What I find interesting is that the center of the "colder than average" area has stayed virtually the same since the beginning of the year.

Here are the April temperatures compared to the average across North America

 

 Once we include MARCH AND APRIL, the map looks virtually identical

 

How about FEBRUARY, MARCH and APRIL? Little change in the map

The entire year from JANUARY through APRIL shows how the center of the cold evolved over the last 4  months

 

The BIG QUESTION will be whether or not the CORE OF THE COLDER THAN NORMAL AIR breaks down, drifts west or east or expands?  More on this later.....

Temperature Ranks this Spring

Just ran the temperature numbers since March 15th. Where does this year's spring temperatures rank so far? Not very warm as you probably thought...79th out of the 143 years of record keeping in Cleveland.

I also circled the warmest and coldest 3/1 to 4/28 periods on the handy little chart below.

Comparing Spring 2013 to Spring 2012

Last spring's weather was an aberration.

...sure it could happen again but the chances seemed small. I explained the 2012 spring conditions and the drought that followed at The Ohio State Weather Symposium in March. (Power Point is here) A year later, the conditions are very different in many ways across the U.S.  Above normal rainfall, temperatures running well below normal and late season snowfall for starters.

Since the growing season is around the corner, lets compare the temperatures, rainfall and drought indices to this time last year. First the temperatures. After the warmest March on record and a very warm April of 2012, this spring since March first has been anything but warm. Late season snow on the 20th of April with flurries on the 24th have solidified this early spring as a bust for Ohio.

Temps vs Normal for March thru April 22nd

Rainfall last year was becoming scarce. Moist condition in winter were disappearing as evaporation from the early spring warmth was taking its tool on the soil. So far this spring, rain has been plentiful across Ohio while major flooding was a big concern for the upper Mississippi River.

Mississippi River flooding from Iowa to almost St. Louis

The Mississippi River was well above flood stage in St. Louis but no where near the record highs set during the Flood of 1993

The Long Term Palmer Drought Index for the week of April 20th shows three distinct difference compared to 2012 at this time. The first is the southeast where conditions are much improved this year. Second is the drought conditions in the western Plains and out west which are only getting worse. Third is the heavy rain and saturated soil across the corn belt.

Whether or not we see any reprieve from the rain will greatly determine how quickly corn can be planted. Corn is only 2% in the ground while last year, the top corn producing states were already 16% planted. Something to watch!

The thousands of record cold and snowfall records across the U.S. from late March through late April hasn't helped.

Spring tornadoes are way down compared to the seasonal average of 492. In 2012, 588 tornadoes were confirmed. So far this spring, the number is more than half of last year's with 226 as of April 25th. 

So what does early May look like? Will we see any warmth? Will we see bouts of cooler periods? While "cooler" for late May means something different than early April, the overall outlook for the next two weeks isn't great. Both long term projections shows the temperatures averaging below average (average high is lower 60s for earl May) which would translate to 40s and 50s.

Map on left is thru May 12th--Map on right is for May 4th--COOL!

What a difference a year makes!

What is Your Definition of a HOT SUMMER?

One of the many things I have learned over the years presenting the weather on television is the strength of the public's perception on how the weather works. The weather data may say one thing about a specific weather trend or event but the power of our senses creates and amplifies inherent biases hardwired in our brains and overwhelms any objective analysis.

How many times have we described some piece of weather history with numbers and they just didn't sit well with you because you perceived weather to be wildly different? We all have some degree of what is called cognitive dissonance--that is the feeling of discomfort (frustration, anger, embarrassment) when simultaneously holding two or more conflicting ideas or beliefs.

Rather than make you feel uneasy about listing scary numbers of summer's by (believe me, I'll have plenty of time for this in later posts) , my QUESTION OF THE DAY is to survey your PERCEPTIONS of the weather.

The question is WHAT IS YOUR DEFINITION OF A HOT SUMMER? WHAT IS YOUR DEFINITION OF A COOL SUMMER?

Snow in April? Has this Happened Before?

Its April 20th and we had snow showers earlier in the morning. I could hear the collective "Where is spring? Its not supposed to snow this late into April!" In most years, you and the rest of northern Ohio would be correct. 

Cleveland Heights

Chesterland

South Euclid

How many times have we seen only a tenth (0.1") of snow AFTER APRIL 20TH? Believe it or not, its happened 24 TIMES SINCE 1895 here in Cleveland.

Here are the years and the days this has occurred. The first numbers are the temps leading up to the day of snow. Notice that this year is the first time we've had an 80+ day followed by measurable snow  36 hours AFTER the 80+ degree high.

2013 - 84, 71, 44 (0.1" - 20th)
2005 - 12.4" over 3 days (23-25th)  
2004 - 70, 62, 49 (0.1" snow late on 27th)
1996 - 60, 73, 58 (0.1" overnight)1993 - 73, 40 (0.1" on 21st)
1978 - 50, 42 (0.2" on 21st)
1971 - 60, 52 (0.1" overnight on 21st)
1968 - 51, 29 (0.2" on 25th)
1967 - 49, 39 (0.1" on 24th)
1963 - 65, 59 (0.3" overnight on 30th)
1953 - 34, 57 over 2 days (1.6" & 0.1" on 20-21st)
1934 - 42 (0.7" on 21st)
1922 - 39 (0.2" on 21st)1920 - 59, 48 (0.1" on 28th)
1908 - 41 (1.4" on 30th)
1907 - 59, 42 (0.2" on 26th)
1906 - 41 (0.2" on 23rd)
1904 - 31 (0.3" on 20th)
1903 - 41 (0.1" on 22nd)
1901 - 35, 40 (2.8" & 1.8" on 20-21st)




Incidentally, how often have we seen measurable snowfall in May? 11 TIMES



1902 - 0.6" on 10th
1906 - 0.1" on 9th
1907 - 0.5" & 0.2" on 4th & 10th
1908 - 0.1" on 2nd
1909 - 0.1" & 0.3" on 1st & 2nd
1963 - 0.1" on 1st
1973 - 0.6" on 4th
1974 - 2.0" & 0.1" on 6th & 7th

Friday's HUGE changes...

Temps continue to fall behind the front...rain moving out.

CURRENT RADAR LOOP CAN BE FOUND HERE

Today/Tonight's Severe Weather Threat

UPDATES ON FACEBOOK AND
TWITTER THROUGHOUT THE DAY

The radar looks fairly uniform this morning. Well defined line of rain and storms in the middle of the country. .
A WATCH might have to be issued for Indiana later this morning. No showers/storms on radar over northern Ohio as of 9AM.

For Ohio, we will see three elements evolve today before the storms arrive: First the strong winds. The pressure gradient is strong along the front as is the temperature gradient. Temps early this morning were in the upper 70s in St. Louis; 45 in Kansas City. The pressure gradient and the low level winds will translate down to the surface reaching 40-45 late today as we reach prime heating. Dew points are also climbing.

The second element is the temperatures. In April, we need a strong southerly wind to reach 80. That should not be a problem later. the only inhibiting factor will be some cloud cover. History tells us that the winds should mix out the cloud deck. Expect a fair amount of sunshine. Morning temperatures ahead of the front already in the 70s!

The third component (the toughest to nail down) is the energy ahead of the main front. Will this energy kick up some spotty storms later today/evening? Once again, history dictates that the chances are pretty good. The HRRR model shows the random, pre-frontal storms very well. The Storm Prediction Center has western Ohio in a slight risk later today for severe storms

Then we await the arrival of the winds ahead of the front. Storms will pass through the area at the right time of day (late evening/overnight) so as to diminish the severe weather threat. A few storms will reach severe limits tonight but it should not be widespread.

Expect rain early Friday, temps will remain in the 60s early. The models continue to push this front through FAST. So look for the rain to move into Pennsylvania by noon Friday. Temperatures will drop quickly into the lower 50s by afternoon. Some sunny breaks behind the front.

Just How BIG have this April's "Ups and Downs" been so far?...

Cleveland Skyline

The dramatic "ups and downs" in recent weeks have caused many to draw the conclusion that this pattern must be something very unique even for spring. Andre has a great blog on his website about how our memory is very selective. We tend to put more weight on recent events or events that are important to us without taking a look at the "big picture" and the data. I've also written extensively about our cognitive biases in how they shape how we perceive the weather (behavioral meteorology) HERE and the human condition pertaining to weather HERE. Our cognitive dissonance couldn't be more apparent in how we view this recent 14 days weather pattern, i.e. One day at 80 then 30s with drizzle and sleet, etc

So how does this April so far compare to the last few years comparing day-to-day HIGH temperatures drops and rises compared to the normal high of the day?  Here are the largest "drops and rises" compared to the daily normal over the 25 Aprils through the first two weeks. For example, if the high was 80 (normal for that date was 60 for a +20 degree difference) and the next day, the high was 45 (normal was 61 for a -16 degree difference), the final difference over the 24 hour period was -36 degrees! These are the numbers I used in the graph below.

Don't be intimidated by this chart. There a lot of numbers here. First, I BOLDFACED the instances of day-to-day positive change (WARMER) of more than 10 degrees. Second, I underlined instances where the temperature change was more than 10 degrees for back-to-back days.  Frankly, I couldn't figure out a good way of illustrating this so the raw data will have to do for now.

Here are some of my notable conclusions:


Recently, 2011 had some VERY big "ups and downs". During one stretch in 2011, temperatures dropped 31 degrees in 24 hours then rose 13 degrees the following day!

April 2010 had an instance where temperatures dropped 20 degrees and then rose 22 degrees the following day.

April 2007 had a 12 degree jump then a 17 degree drop followed by ANOTHER 35 degree drop.

April 1995 from a Sunday to Friday saw a 20 degree jump, a 17 degree drop, a 12 degree drop, 22 degree jump then finally a 19 degree drop!

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The bottom line is that historically, April is known for wild swings in temperature and weather. We just don't want to believe it because what's happening NOW is usually perceived as more significant than what happened in the past.

Trust Local Severe Weather Coverage

In weather situations like today, I would stick to local television stations for severe weather updates versus cable channels. National cable channels that air frequent severe weather updates often generalize their outlooks and coverage.  Most don't know about the specific mesoscale weather variations like the local meteorologists who work there.


During general updates for a multi-state area,  the words "tornado warning" might be said perhaps referring to another area. Yet local viewers often mistake these words to describe THEIR local weather!  Not saying they are wrong all of the time, they just have a tendency to "cry wolf" far too often with "wall-to-wall" when none is required.  Bottom line, watch your favorite local television station for hyper-local weather updates. I can guarantee that we at WJW FOX8 WILL NOT blow the weather out of proportion. We only break into programming during tornado warnings or if the weather becomes severe over a widespread area.

CURRENT WARNINGS CLICK HERE

 Its not the weather that scares people the most, its the words you use to describe it!

Cleveland Home Opener Weather

So far, the front has been relatively inactive. A few spotty showers are popping up but nothing heavy or widespread. CLICK HERE FOR CURRENT RADAR

Expect a few hit and miss showers during the game. I highly doubt we will have any delays.

I will leave you with the team photo of the 1869 Cleveland Forest Citys. Snappy unis!

1869 Cleveland Forest Citys - Courtesy: clevelandareahistory.com