cold duration

I tapped into the climate records from the University of Georgia cold duration calculator.  So, it's not just my imagination, but this past winter has been a particularly prolonged cold winter.  This winter our purple heart plant died, but this plant survived the past 5 winters outdoors.

Has prolonged cold temperatures altered when trees bloom or the arrival of other spring markers? My backyard record keeping could be better, but it looks like a ~19 day delay of spring markers when comparing 2010 with 2009.

Bradford Pear              20-MAR-2010    15-FEB-2009    33 day delay 

Carpenter Bees             28-MAR-2010    09-MAR-2009    19 day delay

Acer palmatum leaf out     02-APR-2010    14-MAR-2009    19 day delay

Flowering Dogwood          03-APR-2010    21-MAR-2009    13 day delay

Asian Wisteria             06-APR-2010    24-MAR-2009    13 day delay

Carolina Cherry Laurel     07-APR-2010    14-MAR-2009    24 day delay

2010 Atlanta snowfall

Today, there is 1/4 inch of snow on the ground and the sunny backyard scene is magical.  Birds are foraging and the bees are mostly tucked inside their hives. The last extensive outside bee activity was 01-Jan-2010 when the mid-day temperature went to 48°F.

Spring is around the corner--I say "bring on the Mahonia and Red Maple bee forage". In the book Eating Animals, Jonathan Safran Foer says "everything is possible again." That's how I feel.

revised 2010 Atlanta rainfall forecast

It was not my intention to so quickly revise my simplistic rainfall forecast, but nine inches of rain in December 2009 (red curve) has changed everything.  Including the December 2009 rainfall, now the best historical rainfall match is 2002 (next year as blue curve) followed by 1983 (next year as green curve) and then 1942 (next year as black curve) .    What is surprising is that all rainfall forecasts are similar and suggest more rain than "average" during Feb-Apr 2010.   In other words, 2010 has the same 2009 trend of too much Feb-Apr rainfall. To avoid clutter, the 2002 rainfall match is not shown.  As previously mentioned, no two rainfall years are the same and this annual rainfall match is no exception. You might want to visit the "official" 2009 climate summary.

2009 Atlanta rainfall and a look ahead

Let's start at the beginning.  Have you ever wondered whether you can find an average year of rainfall in the historical records?  Does such a thing exist in the wild?  With the assistance of the state climatologist, I was able to accumulate Atlanta rainfall information going back to 1930.  Weighting each month equally, 1997 (blue curve shown above) is the best match to the average rainfall year (purple curve shown above).   Put another way, I did not worry whether the area beneath the curve matched (annual accumulation), but compared each month separately using a least squares method.  What about the curve differences?  Atlanta rainfall is not "dependable" and no two years look exactly the same.  More about this latter.

Shown above in the red curve is the 2009 rainfall (so far).  The big 2009 hump in September-October brought flooding, loss of property, lives and bee lives too.  I speculate that the next largest hump (March) adversely affected nectar gathering during our best in-town nectar flow (tulip poplar flowers).  Why so much rain in 2009?  Has the train left the tracks or has the train always been off its tracks?  Probably a little bit of both--Atlanta rainfall is complicated in part to tropical weather influences and let's not forget the butterfly effect.

Back to data mining--I looked at 80 years of record keeping and found that 1977 (shown in blue) is the best rainfall match to our current year (2009 shown in red).  With me so far?   From a honey harvest point of view, I am only attempting a short range rainfall forecast.  Using a simplistic forecast scheme, what can I expect during February through April 2010?  Shown in the green curve are rainfall values for 1978 (the year following the 1977 best match).  In other words, my February through April fall prediction for 2010 is one of lower than average rainfall.  What if I had used the 2nd best rainfall match to 2009?  So as not to clutter the graph, the 2nd best match is not shown.  If you are still interested, the February through April 2010 forecast is similar using the best and 2nd best match to 2009 rainfall.

Shown above is the "official" February through April 2010 rainfall forecast.  It's hard to see, but Atlanta lies between that brown Indiana/Ohio bulls eye and green Florida shading--in a region of no shading (white map color).  In other words, the "official" forecast for Atlanta is one of "equal chance" of 1) above normal, 2) normal or 3) below normal rainfall.  Is this some kind of super computer joke?   What, unable to forecast? 

I don't have much skin in the bee game, but I'll stick my neck out and say that in 2010, Atlanta will not have too much rain during the tulip poplar nectar flowering.  Next spring, I'll review my rainfall forecast using hind sight.