We all knew this Summer was hot, but how about this.  2010 will go down as the Second hottest Summer of all time in Memphis since record keeping began.  The only Summer that was hotter was the brutal Summer of 1980.  Read the stats below.  They are incredible.

(Information is courtesy of the National Weather Service office here in Memphis)

It was a very warm summer across the MidSouth.  A ridge of high pressure remained nearly stationary over the lower Mississippi River Valley from late June through much of August.  There were several days above 100 degrees, 7 to be exact in Memphis and 16 nights at or above 80 degrees!  On August 3, Memphis tied the all-time warmest overnight low on record at 84 degrees.

The number of 90 degree days during the summer was 85, so only 7 days did not manage to reach 90.  Had the high temperature reach 90 degrees on July 17th (the official high was 89), the number of consecutive 90 degree days would have been 79, or 25 days past the old record set in 1980 of 54 days!

Even though this summer was not the hottest on record at any site, it certainly felt the hottest given the copious amounts of humidity in place.  Dew points frequently approached or exceeded 80 degrees which is just about the highest dew points can get.  These extreme humidity values often occurred during the hottest stretches, particularly in August, making the heat index values very deadly.  There were 34 days with heat index values at or above 105 degrees in Memphis, and 15 days with heat index values at or above 110 degrees.  The highest heat index values to occur did so on August 3, 14, 15 when it topped off at a blistering 118 degrees. 

It is pretty rare for the heat index to exceed 110 degrees because as the dew point rises, it takes more energy to increase the air temperature.  Thus, it likely would have been the hottest summer on record if the high humidity was not in place.  The NWS Memphis heat program issues Heat Advisories for heat index values between 105 to 109 and Excessive Heat Warnings when the heat index reaches 110 or better.  Needless to say, many advisories and warnings were issued this summer!

Meteorologically speaking, Summer is defined as the months of June, July, and August whereas astronomical Summer is defined as about June 21 through September 22. 

Below is a listing of the top ten warmest summers since records began.  All four official climate sites in the MidSouth were in the top three warmest. 

Memphis

Highest Average Temperature degrees F
Days: 6/1 - 8/31
Length of period: 92 days
Years: 1872-2010

Rank  Value   Year
  1    85.6   1980
  2    85.4   2010
  3    84.2   2007, 1954
  5    83.3   1952
  6    83.2   1934
  7    83.1   1993, 1977, 1943
 10    83.0   2005, 1998, 1953

You may or may not have heard us talk about displaying weather information on twitter.  If you are not familiar, twitter is media network where one can post thoughts and news headlines and have “friends” that follow the individual’s posts and vice versa.  Our Weather Team has a page and we post really interesting weather information and headlines.  It can be very helpful for you if a storm is headed your way and you need a quick update.  We are also now inserting direct images from our radar and its tools that you won’t find anywhere else.  Street level weather information, as well as advanced Hurricane technological tools.  If you haven’t checked it out please do so and feel free to give us your feedback.  First go to www.twitter.com  You can follow us under the name “Midsouthweather.”  Click on the image below for one of our examples of weather information we insert on twitter.com.

Hurricane Earl is churning in the open waters of the Atlantic.  It is currently a minimal hurricane but is forecast to become a major hurricane in the coming days.  The consensus seems to be a direct hit on the United States remains unlikely.  The storm is still developing and could change paths however as a large fan of uncertainty exists so it will be prudent for all parties involved along the East coast to take careful watch.  I have inserted an Infrared image of the storm taken a few moments ago.  Notice the deep red.  Those colors indicate intense activity near the center of Earl. We’ll track it carefully for you in the coming days.

What was Hurricane Danielle is now a Tropical storm but is forecast to become a hurricane once again.  Here’s the good news with this system.  Strong Surface High pressure off the Atlantic seaboard will curve Danielle away from land as it continues its forward March Westward.  I’m posting a link to the National Hurricane Center’s web site.  This will show you the expected track in the coming days.  Notice the disturbance on its heels.  That will be something to watch in the coming days.  Have a great evening.

http://www.nhc.noaa.gov/

Yesterday I posted rain estimates from Saturday night’s thunderstorms.  Click on the image below for Memphis Metro totals.  Speaking of rain, it appears the area will not see any for quite some time.

Intense thunderstorms rolled through the Mid-South last night.  Some locations received really heavy rain and a few spots saw narry a drop.  One of the many tools we have for severe weather is a product called “Rainfall Estimates” and I have posted the image below.  Keep in mind often times they can be exaggerated but the technology has really improved in the last several years and the estimations are usually rather reasonable as I believe this picture is.  These amounts occured over the last 24 hours.  Notice that areas Northwest of Covington received over three inches.  The darker green illustrates the highest amounts and the light blue shade indicates the low end of amounts.  If your area on the map doesn’t have any color, other than the background green, showers likely missed you.  Click on the Image for more.

NOAA: July Hotter and Wetter than Normal in U.S. 

The July 2010 average temperature for the contiguous United States was 75.5 degrees F, or 1.3 degrees F, (17^th warmest) above the 1901-2000 long-term average, according to the latest NOAA State of the Climate report. Last month’s average precipitation was 3.24 inches, or 0.48 inch above the 1901-2000 average.

Based on records dating back to 1895, this monthly analysis, prepared by scientists at NOAA’s National Climatic Data Center in Asheville, N.C., is part of the suite of climate services NOAA provides.

U.S. Temperature Highlights: July 2010

• The intense heat either tied, or shattered, July monthly temperature records in several East Coast cities.  Washington D.C. recorded an average temperature of 83.1 degrees F, which tied with July 1993 as the warmest for any calendar month on record. Other July monthly temperature records were broken, or tied, in Atlantic City, N.J. and Hartford, Conn.
• It was the hottest July on record for Delaware and Rhode Island. Along the East Coast, each state from Maine to Florida ranked in their top 10 warmest. Only Montana, Idaho, and Texas had below-normal average temperatures for the month.
• The Southeast and Northeast climate regions experienced their third and fifth warmest July on record, respectively. Of the nine climate regions within the contiguous U.S., none experienced a below normal average temperature.

U.S. Temperature Highlights: May through July and Year-to-Date

• The May-July period was the warmest on record for the Northeast and Southeast climate regions and was the ninth warmest for the Central region. This period produced record warmth for: New Hampshire, Massachusetts, Rhode Island, New Jersey, Delaware, Maryland, Virginia, North Carolina, and South Carolina.
• The Northwest had its sixth coolest May-July period. Below-average temperatures were experienced in Oregon (fifth coolest), Idaho (seventh), and Montana (eighth) during the same period.
• In the Southeast, the below average temperatures from the winter were still evident in the year-to-date (January-July) period, as Texas, Louisiana, Mississippi, Alabama, Georgia, and Florida were below normal. Meanwhile, Maine, New Hampshire, Vermont, Rhode Island, and Connecticut have experienced a record warm start to the year, resulting in a record warm year-to-date for the Northeast climate region.

U.S. Precipitation Highlights: July

• Wisconsin had its second wettest July, while Texas had its fourth, Iowa its fifth, and Missouri its eighth. By contrast, it was the 10^th driest July for Georgia and Virginia.
• Much of the Plains and Upper Midwest experienced above normal precipitation, triggered by moist tropical air that fueled widespread thunderstorms. Several of these systems stalled out and caused major flooding in some areas.

U.S. Precipitation Highlights: May through July and Year-to-Date

• From May through July, persistent rainfall made this period the wettest for Wisconsin, the second wettest for Illinois and Iowa, the third wettest for Michigan and fifth wettest for Washington State. 
• Precipitation, when averaged across the nation, was much-above-normal, ranking as the 10th wettest May-July period. On the regional level, much of the northern tier United States was above normal. The East North Central had its second wettest May-July. Both the Central and West North Central region had their ninth wettest and the Northwest had its 10th.
• Precipitation was well below normal in Louisiana for the year-to-date period (January-July), as drought conditions continued to deteriorate. The state was more than 9.5 inches below the long-term average for the year, its seventh driest such period in 116 years. Conversely, Iowa was nearly 10 inches above average, its third wettest start to the year.

NCDC’s State of the Climate reports, which assess the current state of the climate, are released soon after the end of each month. These analyses are based on preliminary data, which are subject to revision. Additional quality control is applied to the data when late reports are received several weeks after the end of the month and as increased scientific methods improve NCDC’s processing algorithms.

Scientists, researchers and leaders in government and industry use NOAA’s monthly reports to help track trends and other changes in the world’s climate. This climate service has a wide range of practical uses, from helping farmers know what and when to plant, to guiding resource managers with critical decisions about water, energy and other vital assets.

NOAA’s mission is to understand and predict changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Visit us at http://www.noaa.gov or on Facebook at http://www.facebook.com/usnoaagov.

On the Web:

NOAA’s National Climatic Data Center: http://www.ncdc.noaa.gov

Ok so this post is going to focus on the dewpoint.  The reason I picked this to blog about is I believe it’s timely considering how important it will be to our heat index.  To me, if a dewpoint is higher than 70 it is very humid.  So why do we as weathermen and weatherwomen use it as a more valuable tool than relative humidity?

Consider this.  Let’s say the humidity is 85% when the temperature is 55 degrees outside.  Now let’s say the humidity is 54% when the temperature is 92.  Which do you think would feel worse?  This is why the dewpoint is such a better measure of “actual moisture” in the atmosphere.  Relative humidity, is just that, relative.  Humidity does not measure the amount of moisture in a column of air.  Rather, it just calculates how close the temperature is to the dewpoint.  Confused yet?  Click on the link below for a better explanation.  I hope you have a great week and thanks for stopping by to read our blog.

http://en.wikipedia.org/wiki/Dew_point

The Mid-South is about to embrace another potentially dangerous Heat Wave which could extend for a prolonged period of time.  I believe a return to temperatures near 100 during the day and around 80 at night for lows is a likelehood.  So essentially what causes a Heat Wave?

In short, High pressure builds in the Mid-levels of the atmosphere.  High pressure forces air to sink and as air sinks it warms and thus compresses.  This is exactly what should transpire for our upcoming week.

Click on the link below for a map of projected weather conditions and positions of specific features  in the Mid-levels of our atmosphere.  Thank you for reading our blog!

http://weather.unisys.com/nam/4panel/nam_500_4panel.html

I have often fielded the question does a 50% chance of rain mean 50% of the area will get rain.  And the answer is, no, it does not.  A 50% chance of rain means there is a 5 in 10 chance it will rain in a given area.  The National Weather Service divides our region into zones.  Each zone has its own individual forecast.  Click on the link below for the latest zone forecast.

http://forecast.weather.gov/MapClick.php?site=meg&zmx=1&zmy=1&map.x=164&map.y=134

Check us out on twitter if you get an opportunity.  You can follow us under the name “Midsouthweather.”

I wish you a pleasant Tuesday evening.