Ag Weather Forum

There clearly has been a change in the weather pattern in the US. The great drought of 2012 has continued into the new year in much of of the Plains and northwest Midwest. However, during the last 7-10 days of February, we saw 2 major storm systems move out of the southwest U.S. and bring heavy snow and rain events to much of north Texas, Oklahoma and southern and central portions of Kansas. These events were not well forecasted in advance by the models.

What has happened? It is my theory that this change in the pattern may have been due to a significant change in the pressure patterns in the Pacific Ocean during the first half of February. In that time period, the Southern Oscillation Index (SOI) became quite negative, which indicates El Nino conditions in the Pacific. Despite the fact the overall conditions in the Pacific are considered to be neutral at this time, I was of the opinion that we were heading towards the El Nino side of neutral. I was not sure at the time what the impact of this would be; however, after seeing what happened in the southern Plains I think this may be the result. El Ninos in the winter can produce significant snowstorms in the southern Plains at a time of the year when this region is normally quite dry.

Now the question is--where do we go from here? Despite the fact that the pattern has changed, it does not mean that this pattern will persist. In fact, the SOI during the latter half of February and on into early March has become more consistently positive. This would be suggestive of a shift towards a more La Nina bias of an overall neutral pattern. A La Nina bias could mean a return to a drier pattern in the southern Plains during the month of March. We will have to see if this works out. Current indications are that early March will continue to feature an active southern branch storm track similiar to late February.

Meanwhile, despite this change in the pattern, it remains quite dry in parts of the northern plains and northwest Midwest. Some increase in precipitation is expected in these areas during the first part of March, but not enough to end dryness concerns going into the spring planting season.

Mike Palmerino

Finally it was interesting to note that the 19 inch snowstorm at Amarillo Texas last week was the third greatest snow on record for this station. The record snowstorm for Amarillo of 20.6 inches occurred on March 25-26 1934. Right in the middle of the Dust Bowl.

Mike

(ES)

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