Monday, May 28, 2012

May 24, 2012 Platte County, Nebraska Tornado.

May 24, 2012 Platte County, Nebraska Tornado.

746 PM CDT THU MAY 24 2012

0536 PM TORNADO 2 WNW CORNLEA 41.69N 97.60W


Home that was hit by the tornado

 Aerial view with the tornado track indicated in green.
Map analysis produced by NWS Omaha/Valley, NE

Another view of the tornado damaged home

Another view of the tornado

Thursday, May 24, 2012

May 23, 2012 Record Heat in Lincoln, NE

May 23, 2012: Record High of 94 F in Lincoln, NE

A record high of 94 F was observed yesterday in Lincoln, NE.  This was the 9th day this year with highs 90 F or higher in Lincoln, NE.  This ties 1934 for the most number of 90 degree days by May 23 (with 126 years of data).

A significant cool-down is expected today (Thursday May 24) and tomorrow (Friday, May 25), then two more hot days on Saturday (mid 90's) and Sunday (near 90F) then cooler again to end the month of May 2012.  Lincoln residents were not so lucky in May 1934.  High temperaturess for the last days of the month exceeded 90 F and 100 F

Lincoln, NE, High Temperatures, May 1934
May 28, 1934:    93 F
May 29, 1934:  102 F
May 30, 1934:  104 F
May 31, 1934:  103 F

Mid summer heat wave temperatures spread across the Great Plains yesterday, May 23, 2012.  The state-wide high temperatures for May 23, 2012 were: 107 F, Dryden, TX; 103 F, Guymon, OK; 102 F, Roswell, NM; 100 F, Dodge City, KS; 96 F, Hebron, NE; and, 94 F, Cherokee, IA. 

The attached map shows yesterday's (May 23, 2012) high temperatures. Note the 111 F south of the TX/Mexico border.

Wednesday, May 16, 2012

January 1-May 15, 2012 Lincoln Temperature Departures from Normal

Daily Temperature Departures from Normal,
Lincoln, NE, January 1 - May 15, 2012
The attached graph shows the daily temperature departures from the normal for each day.  The length of the column indicates the magnitude of the departure.  If the column is red it is above normal and if the column is blue it is below normal.

For example on January 19, 2012 the high temperature was 16 F and the low temperature was 5 F for a daily average of 11 F which was 13 degrees BELOW the normal for that day of 24 F.  The column on the graph for that day is blue and extends down to a -13 degrees departure from normal.

For example on January 30, 2012 the high temperature was 70 F and the low temperature was 34 F for a daily average of 52 F which was 27 degrees ABOVE the normal for that day of 25 F. The column on the graph for that day is red and extends upward to a +27 degrees departure from normal.

Here is a listing of the total number of days between January 1 and May 15 that had above, below and exactly normal temperatures:

Above: 96 days (71% of the days)
Below:  33 days (24% of the days)
Exactly Normal: 7 days (5% of the days)
Total = 136 days

And, as of May 15, 2012, this is the warmest year on record for that time period with data extending back 126 years to 1887.

Tuesday, May 15, 2012

Lincoln Year to date - May 14, 2012 - Warmest on record

Year To Date (May 4, 2012) Warmest on Record for Lincoln, NE.

The average temperature for Lincoln for the time period January 1-May 14, 2012 is the warmest on record for Lincoln, NE. 

Here is a listing of the top ten warmest January 1 through May 14 time periods. 
There are 126 years of data extending from 1887 to the current (2012).

Highest Average  Temperature degrees F
Days: 1/1 - 5/14

Rank  Value  Ending Date
  1    45.4    5/14/2012  2    44.1    5/14/1992
  3    43.7    5/14/1946
  4    43.6    5/14/1987,  5/14/1921
  6    42.4    5/14/2000
  7    42.3    5/14/2006
  8    42.2    5/14/1986
  9    42.1    5/14/1934
10    41.9    5/14/1981

Lincoln is not alone in experiencing an extremely unusually warm year.  The attached map shows the temperature departures for the lower 48 states and much of the Great Plains, Midwest and Great Lakes regions have temperature departures from normal in excess of 6 degrees F.  Some areas have a temperature departure in excess of 10 degrees F.  As of today, May 15 there is no sign of a break in this trend with high temperatures in the mid to upper 80's across eastern Nebraska through the weekend.  The temperatures this week are more characteristic or normal for the time period of late June.

Friday, May 11, 2012

A Ten Year U.S. Tornado Climatology

A Ten-Year Tornado Climatology for the U.S.

Because the states vary so much in size, it is better to examine tornado density (number of tornadoes per 10,000 sq. miles).Unless this is done, looking at the tornado total for Kansas and then Texas wold give misleading results since Texas is much larger than Kansas.

This map, produced by the Storm Prediction Center of NOAA highlights the ten year period 2001-2010 and measures the frequency of tornadoes per unit size or area of 10,000 square miles.

The highest density is in Kansas followed by Florida.  Illinois and Iowa have a higher density than Nebraska.

Nebraska has had a total of 524 tornadoes for this time period (see:
or an average of 52 tornadoes per year during that time period and it's size is 77,358 sq. miles giving it an average of  7 (actual number 6.77) tornadoes per 10,000 sq miles.

Tuesday, May 8, 2012

April 2012 Statewide Temperature Rankings

April 2012 Climate Summary.  From NOAA/NCDC.
According to NOAA scientists, several warm periods across the nation during April brought the average temperature of the contiguous U.S. to 55°F, 3.6°F above average, marking the third warmest April on record. These temperatures, when added with the first quarter and previous 11 months, calculate to the warmest year-to-date and 12-month periods since record keeping began in 1895. 
The 12-month period of May 2011-April 2012 has a nationally-averaged temperature 2.8°F above the 1901-2000 long-term average, while the January-April 2012 months were 45.4°F, 5.4°F above the long-term average.
U.S. Climate highlights - April 2012
  • Warmer than average temperatures were present for a large portion of the nation during April with nine states in the Central and Northeast regions having April temperatures ranking among their ten warmest. Above average temperatures were also present for the Southeast, Upper Midwest and much of the West.
  • Eight states - Illinois, Indiana, Kentucky, Michigan, Wisconsin, Ohio, Pennsylvania, and West Virginia - had average April temperatures cooler than their March temperatures. However, these temperatures were still above the long-term average for the month.
  • According to the Rutgers Global Snow Lab, the April snow cover extent across the contiguous United States was the third smallest on record, despite the late season Nor'easter which impacted the Northeast with snow near the end of April.

Jan. 1-May 7, 2012 Warmest on Record for Lincoln, NE

January 1 - May 7, 2012 Temperature Departures from Normal in Lincoln, NE
The above graph shows the daily temperature departures from normal for Lincoln, NE, from January 1 through May 7.  Blue columns show the magnitude of below normal temperatures and red columns the magnitude of above normal temperatures for each day.  The actual daily normals vary during the year. 

For example, the observed temperatures for January for January 19, 2012 were a high of 16F, a low of 5F and an average for that day of 11F.  The normal daily average for January 19 is 24F, which means this day had a departure of 13 degrees below normal (BLUE column). 

For example, the observed temperatures for March 26, 2012 were a high of 84F, a low of 58F and an average for that day of 71F. The normal daily average for March 26 is 45 F which means this day had a departure of 26 degrees above normal (RED column).

As of May 7, 2012, the year to date average temperature is the warmest on record.  Here is a listing of the top ten warmest January 1-May 7 time periods, with 126 years of data, 1887-2012.

Lincoln Highest Average Temperature degrees F
Days: January 1 through May 7; Years: 1887-2012

Rank  Value  Ending Date
  1    44.6    5/ 7/2012 
  2    43.2    5/ 7/1946
  3    42.9    5/ 7/1992
  4    42.8    5/ 7/1921
  5    42.2    5/ 7/1987
  6    41.3    5/ 7/2006,  5/ 7/2000,  5/ 7/1981
  9    41.1    5/ 7/1931
10    40.9    5/ 7/1986

Supermoon 2012

Supermoon 2012:  The Science Behind the Event

Illustration and information is from

A supermoon is a spectacular sight in which the full moon of a given month occurs at the same time the moon is at perigee – the point in its orbit that brings it closest to Earth. During these events, the moon can appear up to 30 percent brighter and 14 percent bigger to skywatchers on Earth. See how the supermoon, or "perigee moon," works in the infographic.

On Saturday (May 5, 2012) at 11:35 p.m. EDT, the moon will officially turn full. And only 25 minutes later the moon will also arrive at perigee, its closest approach to Earth — a distance of 221,802 miles (356,955 kilometers) away.

The effect of this coincidence is a stunning skywatching sight called the "supermoon."

In fact, this month's perigee is the closest of any perigee in 2012 (they vary by about 3 percent, because the moon's orbit is not perfectly circular). The result will be a 16 percent brighter-than-average full moon accompanied by unusually high and low tides this weekend and into the new week.

Supermoon 2012 Photos:

More photos of the Supermoon:


Supermoon:  the perigee moon of 2012:

The night sky on May 5 was animated by the once-a-year cosmic event of the perigee moon. Popularly known as the "Supermoon", the moon appears much larger above us when the elliptical orbit brings it within 221,802 miles to Earth, the closest point. The effect is magnified during a full moon, when we see our nearest celestial neighbor appear roughly 20 percent brighter and 15 percent larger. Collected here are images taken just before, during, and just after the perigee moon of 2012. -- Lane Turner (27 photos total)

Thursday, May 3, 2012

Jan. 1 -Apr. 30, 2012 Warmest on Record, Lincoln, NE

January 1 -  April 30, 2012 Warmest on Record for Lincoln, NE

The time period of January 1 through April 30, 2012 was the warmest on record for Lincoln Nebraska with data extending back 126 years to 1887.

The above graph shows the daily departures from normal for Lincoln's temperatures.  The magnitude of the departure is illustrated by the length of each vertical bar.  Blue indicates below normal and red above normal.

The daily normals change throughout the time period, so the graph shows the daily departures relative to what the normal is for that day of the year  For example, on January  30, 2012 the high was 70F, and the low was 34F for a daily average of 52F which was 27 degrees ABOVE the normal daily average of 25F for that day of the year.  On February 11, 2012 the high was 17F and the low was -3F for a daily average of only 7F, which was 21 degrees BELOW the daily normal for that date of 28F.  April 2, 2012 had a high of 90F and a low of 57F with a daily average of 74F which was 27 degrees ABOVE the normal of 47F for that day of the year.  And yes, some days were exactly normal. For example, the daily average temperature on April 14 was 51F with a departure of 0 degrees from the normal of 51 F for that date.  The average temperature on February 19 was 30F with a 0 degree departure from the normal of 30F for that date.

There were totals of  85 days with daily average temperatures ABOVE normal, 29 days with daily average temperatures BELOW normal and 7 days with daily average temperatures exactly normal during January 1 through April 30, 2012  The following table lists the monthly totals for this time period.

Total Number of Days
Month      Above      Below     Exactly Normal 
January       22         9            0
February      14        11            4
March         30         1            0
April         19         8            3
Totals        85        29            7 

Here is a listing of the top ten warmest January 1-April 30 time periods for 1887 through 2012.

Lincoln, NE, 1887-2012
Warmest Average Temperature degrees F

Rank  Value  Ending Date
  1    43.1    4/30/2012 
  2    42.6    4/30/1946
  3    42.2    4/30/1921
  4    41.9    4/30/1992
  5    40.9    4/30/1987
  6    40.5    4/30/2006
  7    40.4    4/30/1931
  8    40.3    4/30/1981
  9    40.0    4/30/1990
10    39.9    4/30/2000

January 1-April 30, 2012 Departure From Normal Temperatures

January 1-April 30, 2012 U.S. Temperature Departures From Normal

The attached map shows the observed temperature departures form normal for the lower 48 U.S. States.  For much of the Great Plains and Midwest this has been the warmest January 1-April 30 time period on record.  Many locations had temperatures departures exceeding +10 degrees F.  The only area averaging below normal was the Pacific Northwest.  The map below is a close up view of the High Plains region showing in more detail the magnitude of temperature departures for this January 1 through April 30, 2012 time period.  It has truely been an historic warm start to the year with temrpature records that extend well back into the 1800's.

Wednesday, May 2, 2012

April 2012 U.S. Temperature Departures

April 2012 U.S. Temperature Departures from Normal

The attached map produced by our High Plains Regional Climate Center shows the April 2012 temperatures compared to the 1981-2010 standard 30-year climate normals.  Areas in yellow, orange and red experienced above normal temperatures and areas in green experienced below normal temperatures. 

It was a warmer than normal month for much of the area on the map with the largest departures from normal stretching from western Texas up along the High Plains to the Canadian border.  This extreme warmth made the long term drought in the Texas Panhandle even worse.  Ironically, the cooler than normal conditions in parts of the eastern Great Lakes resulted in a first ever recorded occurrence of April averaging cooler than the previous month of March.

The following map is a closer view of the High Plains region showing the temperature departures from normal for April 2012.

Tuesday, May 1, 2012

May 2012 U.S. Temperature Outlook

Temperature Outlook (Forecast) for May 2012

The Climate Prediction center (CPC) has issued their temperature outlook (Forecast) for May 2012.
There are four categories, A (Above), B (Below), N (Near Normal) and EC (Equal Chances).  Historically, 33.3% of the time the temperatures will be A, B, or N.  Therefore, the numbers in the red area for example are all 33 or higher.  The darkest red area is enclosed by a 50 or higher line meaning the probability of it being warmer than normal is 50% or 17% higher than random chance (33%).   The area of EC means there is no current predictability and all three categories are equally likely (A, B, N).  Based upon this map, the outlook for Nebraska is a highest likelihood of continued warmer than normal conditions in May. 

Two important points, (1) this does not mean every day would be above normal, i.e. it is an outlook for the monthly average, and, (2) this is not a high probability forecast, i.e. the odds favor warmer than normal but only slightly meaning it could also be N (Near Normal) or B (Below Normal) for the month.

If May 2012 averages above normal in temperatures, it will be the 8th month in a row for average monthly temperatures to be above normal for eastern Nebraska.

April 2012 Lincoln, NE, Climate Summary

April 2012 Lincoln, NE, Climate Summary

The graph shows the observed April 2012 daily high/low temperatures (top/bottom of each vertical bar) and the normal highs/lows (red/blue lines) for Lincoln, NE

Average High Temperature = 69.7 F; 5.4 degrees ABOVE normal
Average Low Temperature = 42.3 F; 3.5 degrees ABOVE normal
Average temperature for the month = 56.0 F; 4.4 degrees ABOVE normal

19 days averaged Above Normal
8 days averaged Below Normal
3 days averaged exactly Normal

April 2012 was only 1.0 degrees warmer than March 2012

April 2012 was the 7th month in a row with average temperatures above normal for Lincoln, NE

Highest temperature = 92 F on April 25
Lowest temperature =26 F on April 11

Total precipitation = 3.49 inches, 0.78 inches ABOVE normal

Records Broken:
Record High temperature of 90 F on April 2, 2012. Old record was 88 F set in 1928
Record daily precipitation amount of 2.75 inches on April 14. Old record was 2.33 inches set in 1999
Record High temperature of 92 F on April 25, 2012. Old record was 90 F set in 1989