A Toast to a Better Year

Tomorrow marks the beginnings of a New Year and a fresh slate of weather statistics.  2010 finished stormy as was the case on numerous occasions throughout the year.  Minnesota finished the year with more tornadoes than any other state, with many of those tornadoes nearby in western Minnesota.

Every month but two, October and November, finished with above average rainfall in Fargo Moorhead.   Although, October could be listed as an above average month as the official reporting site at the airport missed out on an additional one inch of rain by just a few miles.

In all, approximately 30 inches of rain fell last year in Fargo Moorhead making it one of the wettest years on record.  Some parts of west central Minnesota reported nearly 40 inches of rain, an astounding amount for this climate.

As we begin 2011, perhaps we should all toast to a quiet and drier upcoming year

Repeating 1996-1997?

The winter of 1996-1997 has become the bench mark that all other winters are judged against.  That winter, 117 inches of snow fell in Fargo Moorhead which is nearly 30 inches more than any other season in the record book.

Since then there has been a few winters when there was talk about having another similar winter, yet, they all fell well short.  In fact, in the past 13 years Fargo Moorhead has averaged 47 inches of snow, which is pretty much exactly at our current average of 46.6 inches.  The snowiest winter during that stretch was the Winter of 2008-2009 when nearly 80 inches fell, although a high percentage of that fell late in the season during the flood fight of 2009.

At no point since that snow winter of 1996-1997 have I ever thought a comparison to that year was warranted, until now.  At the end of December 1996 we had recorded 46.8 inches of snow and depending on how much snow we get Thursday and Friday, we will be very close to that level.   It should be noted that two storms in early January 1997, pushed the total to 65 inches by January 10, which is unlikely to occur this year.

The odds are low this snow season will reach that standard set 14 years ago, but unless the pattern changes quickly, we certainly have Top 5 snowiest winter potential.

Current Snow Cover

It has been so long ( I really should say sooooooooooooooo long) since it has been sunny in the upper Midwest that I have not had a good opportunity to see the snow cover from visible satellite imagery.  Below are two images covering the region.  Most of what you see is snow cover as clouds are few and far between.  As a reminder, the dark areas in northern Minnesota are pine forests and the snow there is just as deep as every where else for the most part, but the pine trees “hide” the snow underneath.

Christmas Snow

For 128 years of record keeping, Christmas day came and went with very little snow falling in Fargo Moorhead.  On only one occasion, back in 1912 did snow accumulate to any consequence when 3.6 inches was measured.  Sure, there was a dusting here or there, but something most would call a snow storm just did not occur.  Considering our climate, I always found it an odd coincidence that Christmas day always seemed to avoid getting any significant snowfall.

Of course that all changed in 2009, our 129th Christmas of record.  A year ago we were in the middle of a large and powerful storm that dropped anywhere from 10 to 20 inches of snow over much of the region.  In Fargo Moorhead, 17.3 inches fell during the four day event, with 8.1 inches being measured on Christmas.

This year the weather looks to be taking us back to Christmas past with a more peaceful and quiet day for the area.  We may all dream of a white Christmas, but most of us probably prefer it not to come on the day itself.

A Copper Moon

Tonight,  the full Moon will pass through Earth’s shadow, turning the lunar orb a delightful shade of coppery-red.

Sky watchers in North America are favored with an overhead view as the eclipse unfolds on Tuesday morning between 01:41 am and 02:53 am CST.

You can visit http://spaceweather.com for full coverage of the event including live webcasts, observing tips, and a look at the surprising connection between lunar eclipses and Earth’s climate.

Sadly, we will not be able to observe this tonight because of the cloud cover associated with our snow event.

December Jinx

The first 15 days of December finished with an average temperature of 6.7 degrees which is nearly 9 degrees below average for that period.  The first half of December ranked as the 19th coldest on record.  If you are wondering when was the last time we started December off this cold, the answer would be last year.

December 2009 started off with an average temperature of just 5.3 degrees.  Previous to that, December 2007 and 2008 also finished below average so it appears we are well on our way to our 4th straight colder than average December.  Another recent cold December was back in 2000 when the average temperature was just 2.9 degrees for the first 15 days.

That December ended up being tied for the 2nd coldest on recorded with an average temperature of -0.3 degrees. Given our projected pattern for the next two weeks it seems doubtful this month will end up that cold, but may stay in the top 20 coldest on record.

My Winter Outlook

In recent seasons, I have been requested to write a seasonal outlook for North Dakota State Climatologist Dr. Adnan Akyuz for his climate bulletin that is issued quarterly.  Attached below is what I wrote for the upcoming Winter Climate Bulletin that will be published shortly.

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Perhaps because North Dakota?s climate has more cold days than warm days the interest in winter outlooks seem to garner the most attention.  The winter of 2010-11 is expected to follow the trend of recent years with colder than average temperatures dominating much of the season.  Plus, current projections would also suggest above average precipitation for much of the state as well.

Many of you have likely heard that La Nina conditions are currently occurring in the Pacific Ocean.  A La Nina is the cold water equivalent to El Nino and is part of a recurring atmospheric oscillating pressure pattern between the western and eastern portions of the equatorial Pacific Ocean.  A La Nina often leads to colder than average temperatures for this part of North America as it influences the upper level wind flow in such a way that arctic air frequently moves into the northern plains.

Although La Nina conditions are a good tool in forecasting probable winter conditions, it is only one of many factors in a complex array of atmospheric and oceanic interactions that influence weather patterns across the northern hemisphere.  Unfortunately, several of these other factors also suggest a higher probability for colder than average temps for this entire region.

One of those other factors is a phenomenon referred to as the Arctic Oscillation (AO). The AO is a climate pattern characterized by winds circulating counterclockwise around the arctic. When the AO is in its positive phase, a ring of stronger winds circulating around the North Pole tends to keep the coldest air in the higher latitudes. In the negative phase of the AO, this belt of winds becomes weaker allowing arctic air to more readily move southward bringing bitterly cold air to the state.  Although accurate forecasts of what state the AO will be in is difficult beyond a few weeks, recent weather patterns hint that the AO will, like last winter, be frequently in the negative phase.

Other factors leaning toward cold conditions are the above average early snow cover across the Northern Hemisphere, a continued quiet Sun, active volcanic activity and the current state of oceanic temperatures around the globe.

Forecasting long-term temperatures, albeit imperfect, is easier than precipitation.  In our relatively dry climate, one or two storms missing or hitting us often make the difference between average and very wet conditions over the course of any three-month period.  Using the past as our guide, the odds favor the winter to finish at least near average and more likely above average for precipitation during the December through February time frame for most parts of the state.

The North Dakota State climate office has links to the National Weather Service?s local 3-month temperature outlooks for the upper coming year.  Those outlooks can be found here: http://www.ndsu.edu/ndsco/outlook/L3MTO.html

The latest winter outlook from the Climate Prediction Center (CPC) is predicting an above average probability of a colder than average winter with equal chances for the winter season to be either average, above average or below average for precipitation for most of North Dakota with the exception of the far western portion of the state where CPC has an above average threat for above average precipitation.

Those outlooks can be found at http://www.cpc.ncep.noaa.gov/products/predictions/.

12th Month of Wet.

December is climatologically the driest month of the year in Fargo Moorhead with an average of just 0.57 inches of liquid precipitation (melted snow and rain).  But our climate is a mix of wet and dry and recently our Decembers have been wet, very wet.

Fargo Moorhead has recorded above average precipitation for the past 8 straight Decembers with the last three years all finishing in the Top Ten wettest.  During the past 8 years, the average December precipitation has been 1.34 inches, which is 235% of normal.  With high amounts of moisture, usually comes with abundant snowfall and the last three years in particular have been very snowy with 19.3 inches falling in 2007, 33.5 inches in 2008 which was the highest December total on record and the 3rd highest total on record falling last year with 24.4 inches.

Although this month has started off with near normal precipitation, but it will probably surprise no one if this ends up being our 9th straight wet December.

Super Cool

Earlier in the week we woke up to some beautiful winter scenes with the trees covered in a glorious white frost. Fog, even when temperatures are well below freezing, is usually composed of mostly liquid cloud droplets (supercooled water).

When these liquid droplets touch objects below freezing, ice crystals begin to grow on the colder surfaces. The interlocking ice crystals become attached to branches in trees and other objects and slowly grow into hoar frost.  This crystal growth turns trees and any other object that is exposed to these supercooled water droplets white, giving the landscape that classic “winter wonderland” look.

Although this phenomenon occurs several times each winter, the Red River Valley is not as likely as other areas to experience hoar frost because a very light wind is necessary for the crystals to grow to greater lengths and of course, the wind tends to blow lightly locally when other areas nearby are calm.