No predictive skill for the groundhog in the period
Asheville NC, USA — The table below gives a snapshot by year since 1988 whether Punxsutawney Phil saw his shadow or not along with the corresponding monthly national average temperature departures in the USA for both February and March.
The table shows no predictive skill for the groundhog during the most recent years of this analysis.
Since 1993, the U.S. national temperature as recorded and reported has been above normal 10 times in February, 11 times in March, below normal 6 times in February, 3 times in March, and near normal 3 times in February and 5 times in March.
|Year||Shadow||February Temperature Departure||March Temperature Departure|
|2011||No||Slightly Below||Slightly Above|
|2008||Yes||Slightly Above||Slightly Below|
|2001||Yes||Slightly Above||Tied Average|
In 2011, much of the U.S. saw normal to above normal temperatures. During the first half of February 2011, a southward-plunging polar jet stream held temperatures as much as 15 ??F (8.3 ??C) below normal in much of the Central and Southern United States.
Warm tropical air advanced northward across these regions during the second half of the month, and average temperatures reversed to nearly 15 ??F (8.3 ??C) above normal.
This flip-flop resulted in near-normal temperatures for February as a whole.Conditions were persistently warm throughout the entire month in the extreme Southeast, resulting in above normal averages for the region.
During March 2011, above-normal warmth dominated much of the southern U.S. and Rocky Mountains. The largest temperature departures were in western Texas and New Mexico, which had its fifth-warmest March on record.
Midland, Texas had four consecutive days (March 16 through 19) of temperatures that tied existing records.Cooler-than-normal temperatures were present in the northern and western areas of the country. Conditions were especially cool from southwestern Minnesota across the Dakotas into eastern Montana.
Within this belt, March temperatures were as much as six degrees below the 20th century average.Take a look at the February and March 2011 maps which give a pretty good idea on the distribution of temperatures across the United States. It really isn’t a “bright” idea to take a measure such as a groundhog’s shadow and use it as a predictive meteorological tool for the entire United States.
February 2011 ranked preliminarily as the 47th coolest February in the 1895 to 2011 record. The preliminary nationally averaged temperature was 33.69 ??F (0.94 ??C), which was 0.96 ??F (0.53 ??C) below the long-term mean.
March 2011 ranked preliminarily as the 40th warmest March in the 1895 to 2011 record. The preliminary nationally averaged temperature was 43.92 ??F (6.62 ??C), which was 1.36 ??F (0.75 ??C) above the long-term mean.
The graphs are part of the NCDC Climate Monitoring Branch monthly products.
REFERENCE: This article is extracted in most part from one originally posted on: www.ncdc.noaa.gov/special-reports/groundhog-day.php by the National Climatic Data Center of NOAA and entitled: Groundhog Day
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