May marks the third and final month of climatological
Spring. So far we have received over eight inches of rain since March
1st officially in Fargo/Moorhead, with, many other areas seeing much
more than that.
Unless we by chance miss out on all the rain in the
forecast, the Spring of 2007 is likely to be one of the top ten wettest Springs
on record, maybe even in the top five. So yes, it has been wet as of
Last year (2006) was so dry, that we’ve seen more rain
since March in Fargo/Moorhead, than we did the first 7 months of last year. It
took until the middle of August last year for us to get our yearly total to
eight inches of rain.
Will this wet phase continue through the summer? Right
now nobody knows for sure. But around here, one or two storms can be the
difference between a wet or dry summer.
The Climate Prediction Center (CPC) has issued their outlook for the upcoming summer season (June, July and August). They are calling for equal chances for both temperatures and precipitation to be either normal, above normal or below normal in this area. This is new terminology, as they use to refer to this situation as near normal climatological conditions were expected.
Currently there is a weak La Nina taking place in the Pacific (cooler than average water temperatures). You may hear that La Nina’s tend to bring drier weather to the Midwest during the summer months. There is not a statistical relationship between the two, yes, some La Nina summers have been dry, but others have been quite wet.
Truth is, long range forecasts are still not much more accurate than a coin toss, plus only give general trends, but as our understanding of the atmosphere continues to increase, so will also the ability of the CPC to give more accurate seasonal forecasts.
As for me, I will continue to take it a week at a time.
You may have noticed with the Greensburg, Kansas tornado
that it was rated an “EF”-5 instead of an F-5 like the tornado that struck Fargo 50 years
ago. The “EF” stands for Enhanced Fujita. Ted Fujita, famous tornado
researcher, used the Fargo tornado, as well as many others, to come
up with the “F”-scale to rate tornadoes based on damage. The damage then would
give a rough estimation of the wind speed.
Through additional research, some weaknesses were found
in the scale. First, wind speed was over-estimated on tornadoes rated F-3 or
higher, plus, the old scale didn’t take into account different types of
structures very well. So the new “EF” scale gives us a more consistent
assessment of damage for current and future tornadoes then we have had in the
past. Plus, a much better estimation of the wind speed of the tornado will be
May is by far my favorite month of the year. I enjoy
the heat of each summer, but each spring I still get amazed at the rebirth of
the area after the long cold winter.
The weather warms up into the 60s and 70s, the trees
leaf out, the flowers start to bloom, plus, when you live in mosquito country,
it is about the only warm month of the year where you normally do not have to
worry about being bitten.
But for us May lovers, there has been a problem lately
and that has been that four out of the last five Mays have been quite cold (last
year being the exception). Cool wet Mays in recent years have forced patience on
many of us as we wait for those first flowers to bloom and the opportunity to
plant our gardens or fields. So far, so good this year temperature wise, I for
one am hoping it continues.
The other day someone came up to me and asked if I have
enjoyed the “easier” forecasts as of late. As a meteorologist I find everyday
and situation a challenge and one of those challenges this time of year is our
albedo has changed.
Albedo is the measurement of how much incoming solar
radiation gets reflective back into space. In winter, fresh snow reflects
around 90% of the of the sun’s energy
back into space. That doesn’t leave much heat left to warm the air. In April,
we have the opposite situation occurring. In early Spring, the Red RiverValley’s black fields absorb much of the sun’s heat so we warm up more than
expected at times.
So for the next few weeks until the fields green up (and
raise the albedo) you may find the forecasted high a bit low on those beautiful sunny days courtesy of black