Moorhead is usually credited with having the warmest
temperature ever recorded in Minnesota
at 114 degrees on July 6, 1936. What is
usually lost in the records is the fact that on this date in 1917, Beardsley Minnesota hit 115
degrees for the actual state record.

It might not sound like a
lot, but that 1 degree is like that last second field goal at the end of a
football game, a victory is a victory no matter how close it is.

If
you are a regular weather watcher, you will hear the term unstable used very
frequently to describe the current or future state of the atmosphere,
especially if a storm is in the forecast. Instability in the atmosphere can be
thought of as the ability of a parcel of air to rise. As a parcel of air rises
it will cool, the amount of cooling varies with temperature and humidity
levels, but averages around 3.5 degrees (F) per thousand feet.

If
the parcel of air rises and cools but still finds itself warmer than the
temperatures aloft it will continue to rise and eventually condense into a
cloud. Condensation is an additional warming process which will cause the air
to continue its rise into the atmosphere.

This
ability of an air parcel to continue to rise into the atmosphere would be
considered an unstable environment. If on the other hand the rising air parcel
cools and then finds itself colder than the air it rises into it would be
forced to sink, which would not induced cloud development and therefore would
be considered stable air.

Here in the Northern Hemisphere
we are of course in the midst of the summer season whereas the Southern
Hemisphere is in the middle of their winter and what a winter it has been so
far.

Brisbane, Australia
had their coldest reading on record and their first below freezing temperature
recorded at their airport last week. Buenos Aires, the capital of Argentina had their first snow
since 1918 a couple of weeks ago where children celebrated their Independence
Day by having snowball fights.

Johannesburg in South Africa
saw their first snowfall since 1981 earlier this month and some cities in South Africa
have seen several snowfalls this winter, which is not unheard of, yet a bit
unusual. Plus a cold snap killed dozens
and sickened thousands more as temperatures plunged to near record levels in Peru.

Here’s
hoping that our upcoming winter is a bit kinder in our area.

We have all heard the old saying “it’s not the
heat, it’s the humidity”, you may have even said that these past few days, but
what you really should be saying is “it’s not the heat, but the dew
point”.  Relative humidity is exactly
that, relative. 

Relative Humidity is
high nearly every morning of the year and then drops off and is at its lowest
point during the late afternoon hours when the high temperature occurs.  Relative Humidity has been in the 40s percent
these past few afternoons, not as high as you may have thought, but that is a
lot of moisture when the temperature is 95 degrees. 

A better way to know what your comfort level
will be is to watch the dew point and remember that dew points in the 40s
you’ll be feeling great, in the 50s, you’re still comfortable, moving through
the 60s, most feel slightly uncomfortable, but when the dew points are in the
70s no matter what the temperature, nearly everyone is uncomfortable and the
word sultry will probably come to mind

A viewer sent
us an email asking why the sky turns green, especially in tornadic storms. 
There is not a definitive answer as to why some storms have a greenish hue to
them, but this phenomenon seems to occur the most when an unusually high amount
of water is present in a thunderstorm. 

Strong updrafts are required to maintain
high water levels within thunderstorms and these are the types of storms that
can produce tornadoes and hail, but the greenish tint is not associated with
tornadoes as most tornado producing storms do not appear green.  Hail is also
associated with green storms, but hail is also not believed to be involved in a
storm turning green. 

Instead, especially under low light conditions seen in the
evening when most storms occur, red light is scattered by the atmosphere, the
remaining light is selectively absorbed by the water within the storm leaving
just the green light rays to find their way into our eyes. 

Much of this past week we saw low temperatures drop off into
the 50s and very commonly, it was referred to as “cool” by many of my
co-workers.  If you consider low
temperatures in the 50s this time of year cool or not is of course always a
matter of personal preference, but one thing is for sure, 50s is average for us
this time of year. 

On only three days of
the year is the average low temperature in Fargo/Moorhead at 60 degrees, those
days would be July 15, 16 and 17, the rest of the summer our average low is in
the 50s. Obviously, these are only averages and we wake up to 60s frequently,
even an occasional morning in the low 70s, but the next time you wake up to a
low in the 50s, call it cool, mild, cold or hot, that is your preference, but
we can all safely call it average.

It was on this date in 1936 that Fargo/Moorhead
was in the midst of a heat wave unlike any other since records have been
kept.  It was the fifth straight day of
temperatures of 100 or more, with several more scorchers yet to come.  The high temperature in Fargo was above 90 degrees from July 4 until
July 18 with nine of those days at 100 degrees or higher. 

What makes today unique was not the high
temperature of 110 degrees, although that is the second highest temperature recorded
locally, but the low temperature of 82 degrees that morning.  The all-time record high low in Fargo was that 82 degree
morning 71 years ago today.  Record high
minimums are tough to break as the temperature has to stay above the record
from midnight to midnight, so it will probably be broken eventually, but in
would need to be in the middle of two very hot days. 

Since our wet-cycle started in the
early 1990s, extremely hot days have been rare in this area.  The cloudier conditions that produced all the
rain, plus the wet soil limited the potential for temperatures to get much
beyond the low 90s. 

Last year was the
exception, although our 90 degree plus days were very close to the long term
average, we did manage to hit 100 degrees two times in 2006, a 101 on July 15^th
and a 102 on July 30^th.  Those
were just our second and third 100 degree days since 1989 and our first since
1995.  Until last year, we had only hit
97 or 98 degrees four times since 1995. 

Why do I mention this all today? 
Tomorrow afternoon looks to be one of those rare scorchers we have seen so
few of in recent years.   

July is the warmest month of the year for most locations in
the northern hemisphere.  This is
certainly true in our area.  The average
high in Fargo
this month is 82 degrees with a range from 80 to 83 and the average low is 59
degrees with a range of 58 to 60.  

Therefore, the monthly mean temperature is nearly 71 degrees which is
five degrees warmer than the mean average temperature for June our third
warmest month. 

The second warmest month
as you may have guessed already is August, with a monthly mean of 69
degrees.  But August is also the month
when our average high and low temperatures begin to decrease and sometimes the
first hints of fall move into the valley.

When you celebrate our nation’s birthday you may
think of hot and humid weather.  Truth
is, this area has not had a hot 4^th of July since the 1980s. 

Our record high for this date is 97 degrees
set back in 1989.  Believe it or not,
that was also the last time it was 90 or above on the 4^th of July in
Fargo/Moorhead.  Then again, it may
surprise you that it has never hit 100 on this date.
 
Since that record high 18
years ago, it has been in the 80s only five times, with most Independence Days
seeing a high just in the 70s.  I say
most of the years because two of the years, 2004 and 1992, our high was only in
the 60s, including the second coldest July 4^th ever back in 2004
when our high was only 65 degrees.