IEM Daily Feature
Wednesday, 17 July 2013
Wednesday, 17 July 2013
Easterly winds aloft
Posted: 17 Jul 2013 05:17 AM
The weather pattern earlier this week was a bit strange with the
southern plains experiencing a storm system that traveled west! The
winds well above the ground surface, that help guide storm systems,
were actually from the east. The featured chart looks at the frequency
of easterly winds at a height of 200 hPa (millibars), which is about 7-
8 miles above the earth surface. The chart presents 12 wind roses, one
for each month for the sounding site near Omaha. The site launches a
weather balloon twice per day, providing a vertical profile of
temperature, humidity, pressure, and winds. The wind roses provide
frequencies of wind direction and speed. Westerlies clearly dominate
for all months of the year. Each month is labelled with the percentage
of observations that are primarily easterly. The highest percentages
(although meager) are in the summer time, which is when the jet stream
(very strong westerlies) is furthest away permitting such flow to
occur. So while such events are very rare, this is the time of year
when they most frequently happen.
Voting:
Good = 84
Bad = 16
Tags: sounding
Voting:
Good = 84
Bad = 16
Tags: sounding