Oppressive heat envelopes the Mid-South - records fall

Very strong high pressure built in from the west, where temperatures have routinely been above 100 for days to even weeks.  Even a fair amount of humidity (dewpoints in the low to mid 70s), which would typically be a deterrent to extreme heat, could not keep temperatures from reaching the mid 100s area-wide.  In fact, the combination of heat and humidity resulted in heat indices well into the danger category, topping out between 115-120 degrees.

The following temperature records were set today:

Memphis International Airport, TN - 106 degrees. This marks a daily record (previously 103 set last year) and ties for the 4th hottest day on record.  The all-time record in Memphis is 108, set July 13, 1980.

NWS Office, Germantown, TN - 105 degrees. This marks a new daily record, previously 103 set last year.

Cirrus Weather Solutions, Bartlett, TN - 105.1 degrees. This is the second hottest temperature recorded in Bartlett since WXLIVE was installed in 2005, trailing only August 15, 2007 (106.0 degrees).

Jackson McKellar-Sipes Airport, TN - 105 degrees. This marks a daily record (previously 102 set in 1987) and ties for the 5th hottest day on record.  The all-time record in Jackson is 107, set July 27, 1952.

Tupelo Regional Airport, MS - 106 degrees. This marks a daily record (previously 102 set in 2006) and ties for the 8th hottest day on record.  The all-time record in Tupelo is 109, set July 29, 1930.

Jonesboro, AR - 107 degrees. The daily record was missed by 2 degrees.  The all-time high temperature at Jonesboro is 116.

Little Rock Adams Field, AR - 114 degrees. This sets both a daily record (previously 107 set last year) and a new all-time record for Little Rock.  The previous all-time high was 112 set July 31, 1986.


North Little Rock, AR - 111 degrees. This marks a daily record (previously 104 set last year) and ties the all-time record set August 30, 2000. 

The very hot start to August is on the heels of the warmest June-July period on record.  The average temperature for June-July was 84.9 degrees, which tied 1980 for the top spot.

The MWN Forecast calls for a slight reduction in the heat, but more humidity Thursday and Friday as a cold front moves into the region but stops short of passing all the way through.  Moisture typically "pools" ahead of these summer front, thereby increasing humidity and making it feel worse.  Expect heat indices of 115 again on Thursday and about 110 on Friday.  Excessive Heat Warnings continue through Friday morning and could be extended into the weekend.  Please exercise extreme caution in the oppressive heat and follow the safety tips we have published on this blog.

Metro area temperatures as of mid-afternoon, August 3, 2011

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.

How many ways is there to say "it's hot??"

Do all of the recent Heat Advisories, Excessive Heat Watches, and Excessive Heat Warnings have you confused and wondering why we can't just say "IT'S HOT"??  I'll get to that in a minute.

First a few stats about the Memphis summer of 2011:

• Since May 28, there have only been 5 days that the temperature has NOT reached at least 90.  In July, we reached 90 every day except the 7th (it was 86).
• So far, there have been 7 days in which the low has not dropped below 80.
• The average temperature for June-July 2011 is 84.9 degrees, which ties 1980 for the warmest June-July period on record.  Yes, THAT 1980!

So, about all those watches and warnings.  What do they mean and why does the NWS issue one over another?  The following criteria are used by the Memphis NWS office, as well as many other offices that have not adopted their own criteria (which they are allowed to do).

Heat Advisory - Generally issued when the heat index will be 105-109 degrees for at least a couple of hours during the day and the overnight temperature will remain at or above 80 in the city (many times 70s are experienced in the suburbs).  Issued when the criteria will be met within 12-36 hours.

Excessive Heat Watch - Issued when the heat index is forecast to be at or above 110 degrees within 24-72 hours.

Excessive Heat Warning - Issued when the heat index is expected to reach 110+ degrees and overnight temperatures will remain above 75 degrees in the upcoming 12-48 hours.

So, the main threshold to watch for is the 110-degree heat index.  An Excessive Heat Watch may be issued 3 days in advance of a forecast heat index of 110.  Then, the day before the event, if the heat index is expected to only reach 105-109, a Heat Advisory will replace the Watch.  If the heat index is still expected to hit 110, the Warning will be issued instead.  An Advisory is basically a "toned-down" Warning.  A Watch is issued for longer lead times (similar to a Tornado Watch, which means conditions are favorable, versus a Warning, which means the event is imminent).

Hopefully this helps sort out the plethora of headlines the NWS has used during this heat wave.  By the way, the Memphis office has put together a well-done summary of all of their watch and warning products.  You can find it here: Headlines Issued by NWS-Memphis.

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For weather information for Memphis and the Mid-South, where and when you need it, visit MemphisWeather.net on the web, m.memphisweather.net on your mobile phone, download our iPhone or Android apps, or visit us on Facebook or Twitter.