Big Drop

This past Monday Fargo Moorhead had a high
temperature of 37 degrees.  Twenty four
hours later it was -13 degrees.  That is
a 50 degrees drop in 24 hours. 

In this area we tend to take such swings
in stride.  Truth is, much of the human population lives in areas that may
not get a 50 degree swing in an entire year, let alone in one day.  The
average worldwide swing from coldest to highest temperature in a year averages
between 70 and 90 degrees, not much higher than what we did in less than 24
hours earlier this week. 

Of course our yearly temperature range averages
between 120 and 140 degrees.  Only some areas of Siberia have ranges in
temperatures higher than those found near the geographical center of North America.

Up the Ladder

Several people have called or emailed to ask on what
date the average highs and lows hit bottom, then turn around and start
increasing.  The average high and low in
Fargo Moorhead bottom out at 15 and -3 degrees on January 11 and stay there
until January 22 when the average high increases by one degree. 

January 23 is the first day that both the
average high and low increases which then starts the slow climb that will peak
in the middle of July when the average high and low will be 83 and 60 degrees. 

Our averages will make a very slow climb the
next several weeks and the average high will not reach the freezing point until
March 10.  Our average high will hit 50
degrees on April 8, 60 degrees on April 24 and the average high of 70 degrees doesnt
arrive until May 16.

Sun Dogs

Sundogs can be a common feature when the weather turns
bitterly cold. Although sundogs can
occur at anytime of the year, they are most common when temperatures are below
zero. Sundogs are created by the refraction or reflection of light through ice
crystals. 

These ice crystals can be
found in cirrus clouds, the wispy clouds seen at any time during the year, or
in ice crystals floating in the air, commonly referred to as diamond dust.   The ice crystals that cause sundogs are hexagonal prisms (six sided), usually
elongated and many will be flattened. 
Usually the best sundogs
occur when all the ice crystals are the same shape and size with a common orientation
from the sun which helps enhance the
optical effect.  

The different optical effects
the ice crystals cause will always be formed at an angle of 22 degrees from the
sun, be it a sundog
or a full halo.

Analemma

I was recently asked two questions
that have a similar answer.  One
individual asked if daylight will increase the same amount every day and the
other person asked how many miles per day the suns
direct rays move between the Tropic of Capricorn and Cancer.  

Due to the earth’s tilt on its axis and its
elliptical orbit around the sun, the
location of the sun above the
horizon is not constant from day to day when observed at the same time on each
day.  This effect causes the sunrise and sunset
times to change at a different rate each day from one solstice to the
next.  These effects will also cause the suns angle to change at a different rate each
day.  

This concept is placed
on most globes as a figure eight diagram referred to as an analemma.  If you look up that term using one of the many internet search engines, you’ll discover much more information.


2007

2007s average temperature was 43.1 degrees in
Fargo Moorhead, which is 1.9 degrees above the long term average. Although you may not think that is much over
the average, it was enough for 2007 to be tied with numerous other years as the
10th warmest year on record.

Of
interest, because we tend to get more severe cold than warm weather, it takes a
colder year to make it into the top 10.
For example, a year would have to be 3.5 degrees below the long term
average to make it into the top ten coldest years.

Continental locations like the Red River Valley tend to have extreme temperatures
differences from summer to winter and last year was no exception. Fargo Moorhead’s
coldest temperature last year was -28 degrees on February 7 and the highest
temperature was a 99 degree reading on July 7.

Snowy December

December 2007 was certainly a snowy month.  Fargo Moorhead received 19.3 inches of snow
for the month at the official measuring location in north Moorhead. 
A vast majority of that snow fell during the back to back storms that
dropped around 14 inches during the first week of the month. 

That ranked last month as the 6th snowiest
December since snow records began in 1887. 

I have heard much talk about this being another 1996-1997 winter, but as
of January 4, 1997, we had received 57.5 inches of snow, this year, only around
20 inches has fallen, which by the way, 
is only a few inches above the long term average to this date. 

The area may finish the season above average,
or the rest of the winter may be relatively snow free, but either way, another
1996-1997 type winter is extremely unlikely.

Perihelion

Yesterday at 5:50 PM local time, the earth was
at perihelion, or in other words, the earths closest approach to the sun. Because the earth travels around the sun in an ellipse rather than a circle, the distance
between the earth and the sun varies
from approximately 91.5 million miles today, to around 94.5 million miles on
July 7 when the earth will be at aphelion.

This may not seem right, considering
it is winter in the northern hemisphere in January and yet we are closest to
the sun. But, our seasons are
actually determined by the tilt of the Earth and not the earth’s proximity to
the sun. This fluctuation in distance causes a variation
in the amount of heat received from the sun
to vary by plus or minus 3.4% at the outer edge of the atmosphere.

Although, at ground level, much of this deviation
is lost.

Another Wet One

Fargo
Moorhead received over 26 inches of rain in 2007, a good five inches above the
long term average.   Most of that surplus
fell in 
May and in early June which caused the summer flooding along the Red River. 

With
just a few exceptions most years since 1993 have been wetter than average.  Although 2007 was not wet enough to get into
the top 10 wettest years on record, three such years have occurred since
1993.  These years would be 2000 which
was the wettest year recorded with 34.75 inches of rain, 1998 which ranked
fourth with 31.85 inches and 2005 that ranked fifth with 30.50 inches
measured.  

Just a year ago we were
finishing a dry year (2006) and many thought our wet cycle was over, perhaps it
is and 2007 was just an aberration, no one knows for sure.  Eventually this area will go dry again; it is
just a matter of when, not if.

2007

As 2008
begins a quick look back at the weather in 2007 is in order. Probably the most significant weather events
in Fargo Moorhead in 2007 were the flooding along the Red
River
and the large hail event in September.

The Red River
crested seven times from April to June, with the highest crest occurring on
June 8 at just under 31 feet. This was
the second highest summer crest observed on the Red River
in Fargo Moorhead.

The other big event
caused many residents to be awakened by hail the size of tennis and baseballs
during the early hours of September 21.
The hail caused millions of dollars worth of damage locally to roofs,
windows and vehicles.

But the biggest
weather story in the region last year was the EF-4 tornado that hit Northwood, ND
on August 26, killing one and causing widespread damage throughout the city.