Water Year

Today marks the last day of the year, the water year that is.  The term water year is used by climatologists and hydrologists to track the use of water resources over its cycle of utilization.  October is used as the beginning of the water year because across much of the United States this is the time of year when water inputs begin to exceed loss to evaporation.  Our current dry stretch started toward the end of August 2011, so this past water year demonstrates very well how even by historical standards how truly dry it has been this year.  During the past twelve months, 14.42 inches of rain and melted snow has been recorded at the airport.

That ranks as the 11th lowest total on record and the least amount of precipitation during a water year since the drought in the late 1980s.  The record driest water year was 1935-1936 when just 9.77 inches was recorded and the wettest was two years ago when 32.79 inches fell during the 2009-2010 water year

The Cold was Cold

Antarctica is by far the coldest area on the planet.  The coldest temperature recorded on earth was recorded at the Russian, Vostok Antarctica research station in July, 1983 when the temperature plunged to -129 degrees.  That same station, just last week, recorded a low temperature of -119 degrees on September 16.   That was very close to the coldest temperature recorded on earth during the month of September of -122 degrees at that very same site.

This past Antarctic winter finished colder than average over most of the continent.  Not surprising then, that the sea ice in the southern ocean has broken many daily maximum extent records in recent weeks, but remained slightly below the record level set back in 2007.  There has been research that has shown that the Arctic and Antarctic tend to oscillate oppositely, so as the Arctic continues to record well below normal ice conditions, Antarctic has continued to record much above average ice conditions in recent years.

Perceptional Weather

We all have weather perceptions.  If Phoenix is mentioned, hot and dry comes to mind.  Florida, humid.  North Dakota or Minnesota, many would say cold and snowy.  Of course such perceptions have some truth to them, but any one climate is far more variable.

A week ago, September 18,  when Hector Int’l recorded the first frost of the season, I noticed that Int’l Falls, Minnesota reported a low of 20 degrees that same morning.  My perception of Int’l Falls is cold and therefore a temperature that low did not make me instantly think record.  In fact, when I did discover that was a record, part of me was surprised.  Yet, that 20 degree low in Int’l Falls, not only broke the record for the day by 7 degrees, it almost broke the all-time lowest temperature recorded in the month of September of 19 degrees, which was set just last year.

So even by Int’l Falls’ cold standards, that was a chilly morning for so early in the season.

The Typhoon Did It

When Hurricane Isaac was moving toward the United States, several individuals emailed and asked if it would have any impact on us locally. Historically, it has been rare for the remnants of a hurricane or tropical system to bring rainfall into this area.  Instead of getting rain from a tropical system, a hurricane may help alter the upper level wind flow to temporarily adjust the pattern that would influence our weather in that manner.

That is particularly true with western Pacific typhoons.  Powerful typhoons in particular often help form a large ridge of high pressure to their east, which induces the formation of an area of low pressure and a corresponding trough east of that ridge in the Aleutian Islands.  That storm in turn tends to advect warmer Pacific air into Alaska.   The colder air over Alaska is then forced south into the lower 48 states impacting areas east of the Rocky Mountains in particular.

In some ways, typhoons in the Pacific can alter our weather more than their hurricane cousins in the Atlantic.

The Last Hurrah?

In the spring, we are often looking forward to recording our first 60, 70 or 80 degree day of the year. In the autumn on the other hand, it is difficult to know when we have experienced the last such day of the year.

This past Saturday, the official high temperature was 88 degrees and based on a few conversations, many of you probably felt that was the last hurrah of the season.  The average last 80 degree day is September 29, yet, historically an 80 degree high temperature has been recorded approximately every other year during the month of October.  Plus, the last day with a record high in the 80s is on October 25.

Although we have cool off in recent days, considering how dry the top soil continues to be, plus the overall warmth we have experienced much of the year, another day or two in the 80s will likely not surprise any of us.

One

One.  That is how many days the high temperature was below 70 degrees this past summer.  If you are thinking that would be a record, you would be correct.  This past summer tied 1988 and 1933 for the fewest days with a high temperature below 70 degrees.

The summer with the most highs below 70 degrees was in 1958 when 25 such days were recorded and that cool summer of 2004, that many will likely remember, 20 such highs were recorded.  The last day with a high in the 60s in Fargo Moorhead was back on June 11.  Meaning, the cooler weather that will move into the area next week will be the coldest in over three months.

The temperature may stay in the 50s in some areas next Monday and Tuesday which has not been recorded locally since May.  Although there will be our typical day to day differences and the occasional day with above average temperatures, but the overall trend will be for cooler than average temperatures the rest of the month after this weekend.

A New Old World Record

Nearly 100 years ago, on July 10, 1913, a temperature reading of 134 degrees was recorded at the Greenland Ranch in Death Valley, California.  At the time that was the highest temperatures recorded with proper measuring techniques anywhere on earth.

Nearly a decade later on September 13, 1911 a report of a temperature of 136 degrees was allegedly taken at El Azizia, Libya to establish a new world record that still holds to this day.  That is until now.  The World Meteorological Organization recently decided to drop that particular reading from the record book.  There is always been some suspicion to that reading in Libya in 1922 and after much research it was determined that indeed that temperature was likely bogus.

Therefore, that temperature set nearly a century ago in Death Valley is now considered the warmest temperature recorded in the world.  So if you have ever had the chance to go to Death Valley, you can now officially tell your friends that you visited the hottest place on earth.

A Notable Week

The 91 degree high on Monday pushed our yearly total of 90 degree days to 24.  That one extra day moved the ranking for the year from tied for the12th highest such total, to tie for the 9th highest yearly total since 1881.  The other two years tied for 9th place are 1931 and 1939.

This year was the first time since 1988, the record breaking year with 39 days with temperatures at or above 90 degrees, to end up in the Top 10 for most 90 degree days.  Also of note this past week was the 36 degree low on Sunday, September 9.  That was the earliest 36 degree low since the cold summer of 2004 and several days before the average date of September 14.

The National Weather Services uses 36 degrees as the “frost” temperature (they use the term “freeze” to describe 32 degrees).  Since 1900 there has been no trend in the average first 36 degree temperature, although, the average first 32 degree low has trended later in the month by nearly one week.

 

The Possibilites are Endless

I turn 50 today.  I do not say this to garner the usual Happy Birthday wishes, or to the younger generation to perhaps earn some sympathy.  Instead, that even after living on the planet for a half-century, and forecasting the weather now for almost half of those years, I have never lost my amazement of the atmosphere and the weather it brings.

More particularly, what it can bring, as even after 50 years, I have only observed a small portion of what could occur.  Most of the time when I hear a sound byte on television about someone saying “I have never seen anything like it”, it is more often then not an example that most of us have very short weather memories.  Yet, having written that, our modern industrial civilization has in fact, not come even come close to seeing everything the atmosphere can conjure up and a look at history, well beyond my mere 50 years, is a reminder of what those possibilities are in the future.

August 2012

Although the end of the month may not have felt like it, as a whole, the month of August was our first month since May, 2011 to finish with an average temperature below normal.  Last month the average temperature was 68.8 degrees which is 0.5 degrees below the current 30 year average of 69.3 degrees.

Granted, that means last month finished right at the average, as did a few other months in the past year, yet, it was still the first month to finish even slightly below average to end our above average streak at 14 months.

Last month may have finished near average for temperatures, but well below average for precipitation.  The airport recorded only 0.92 inches of precipitation during the 31 days of August.  That was the lowest total since 1984 (which was the driest on record with 0.18 inches) and tied last month as the 13th driest since 1881.