Past IEM Features tagged: wind

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Hourly Wind Speeds

22 Dec 2016 05:36 AM
Winds were gusty again on Wednesday with the highest wind speeds reported late in the evening. This is not what a typical wind speed pattern throughout the day in December. The featured chart presents hourly wind speed climatologies for the Ames Airport for the months of April, August, and December. Each trace shows the general pattern of highest speeds during the daylight hours. This is due to mixing of higher speed air above the ground down within the boundary layer as the sun heats the ground, which drives the mixing.

Voting:
Good: 7
Bad: 0

Tags:   wind  


Wind Direction

27 Oct 2016 05:40 AM
The featured chart displays a time series of wind direction reports from all automated airport weather stations in the state. A low pressure system moved over the state yesterday and a high pressure system settled into the state overnight. The impact of both systems on the distribution of wind direction reports is interesting to look at! The chart shows consistent wind direction reports on Tuesday from the east and southeast. The circulation around the low pressure system on Wednesday spread all the reports to show all directions reported at the same time in the state. The high pressure overnight effectively reversed all those reports as the circulation is opposite. Kind of neat!

Voting:
Good: 10
Bad: 0

Tags:   low   high   wind  

Wind Climatology

11 Aug 2016 05:42 AM
The featured chart displays daily wind speed climatology for Des Moines. Wind can be broken up into vector components. The u component is the east/west portion of the wind and the v component is the north/south portion. This component analysis is useful as the v component is primarily responsible for warm/cool air mass transport into the state. The top panel shows the daily component average wind speed and the bottom panel shows the total wind speed average. You may wonder why the magnitudes do not match well between the plots. The top panel is vector averaged, so for example a 10 mph north wind report and then a 10 mph south wind report would yield a vector average speed of 0 for both components (zero net transport). The top panel nicely shows the period each year where cool or warm air transport is the most common.

Voting:
Good: 7
Bad: 1

Tags:   wind  

Monthly Winds

17 Mar 2016 05:37 AM
A strong storm system to our east helped bring very strong winds to the state on Wednesday. Having windy days in March should be expected as it is one of our windiest months as shown by the featured chart of monthly average wind speed and direction for Ames. Only April is shown to have slightly stronger winds than March. Springtime often features strong contrasts in temperature which drive windy conditions. Winds will be brisk today, but a bit lighter than Wednesday!

Voting:
Good: 8
Bad: 0

Tags:   wind  

Wind Direction and Dew Point

19 Jun 2015 05:38 AM
Earlier this week, the average dew point at a given temperature was featured. Today's feature show the combination of average dew point for a given wind direction. On Thursday, dew points were comfortable with a northerly wind. The featured chart shows a clear relationship between the wind direction and the average dew point for June at Des Moines. Of course, our major source of humidity comes from the south, so it would make sense that our dew points are higher with a southerly wind.

Voting:
Good: 30
Bad: 14
Abstain: 25

Tags:   wind   dewpoint  

April Wind

23 Apr 2015 05:48 AM
The past three days have been plenty windy as strong northwest flow has persisted. The featured chart presents the daily average wind speed and direction for Des Moines Airport this month. Winds during the daytime are much stronger than at night as the sun promotes lower atmosphere mixing during the day, which brings higher speed air down to the ground where we live! The climatology for April is around 10-11 MPH, so this year is not much windier than average.

Voting:
Good: 10
Bad: 5
Abstain: 5

Tags:   apr   wind  


Days with 40 MPH winds

30 Mar 2015 05:40 AM
Sunday was a very windy day over Iowa with gusts over 40 miles per hour for much of the state. The featured map presents the average number of days per year that the peak wind gust for the day was over 40 mph. Local terrain and siting can make a big difference for this metric as obstructions will slow down the wind. Today will be another windy day with much warmer temperatures than what we saw this past weekend.

Voting:
Good: 18
Bad: 12
Abstain: 8

Tags:   wind  

Windy When Warm

17 Mar 2015 05:43 AM
Temperatures soared on Monday with highs exceeding 80 degrees for much of the state. Sioux City was able to reach 90! Strong winds were also present with the very warm temperatures, which as shown by the featured chart is very common when temperatures get this warm in March. The chart shows the frequency of having a 10+ knot wind speed present at a given temperature in March. As temperatures increase, the chance that strong winds are present increases as well. Restating, strong winds are necessary to help produce very warm conditions in March. On the cold end of temperatures, the opposite is true. Brisk winds at night time help to keep the lower atmosphere mixed and near surface air temperatures are not able to cool to very cold levels.

Voting:
Good: 19
Bad: 8
Abstain: 2

Tags:   wind   temps  


note that the chart is only for winter season months

Pressure Gradient Winds

16 Jan 2014 05:55 AM
After a windy Tuesday, winds are on the increase today and expected to gust upwards of 50 mph. These strong winds are forced by horizontal differences in pressure as air moves from areas of higher pressure to areas of lower pressure. The featured chart presents the combination of an approximate pressure difference over the state to the observed wind speed for Des Moines. An informal forecasting rule of thumb is that for every 4 millibars difference in pressure over Iowa leads to a wind of 10 more miles per hour. For example, a 12 millibar difference should support a 30 mph wind speed. The chart would indicate that this is a fair approximation with most of the distribution near the theoretical line.

Voting:
Good: 41
Bad: 7
Abstain: 7

Tags:   forecasting   wind   pressure  


Sustained Winds

04 Nov 2013 05:37 AM
Sunday was a very wind day over Iowa thanks to a deepening storm system to our west. For Des Moines, the peak sustained winds over a three hour period was 23 mph during the afternoon hours. The featured chart presents the IEM computed daily maximum three hour sustained wind speed for Des Moines. Note, this value is based on hourly reports and not a direct measure of sustained winds over the hour. The chart shows the annual cycle with peaks in spring and fall along with the minimum during summer. While thunderstorms can bring momentary bursts of 70+ mph winds, the sustained winds are powered by strong and large storm systems feeding off the sharp contrasts in air masses. These types of systems are not found around here in the summer time as the cold air masses are relegated well north. The two days shown over 50 mph were 3 April 1946 and 5 May 1950.

Voting:
Good: 42
Bad: 4
Abstain: 3

Tags:   wind  


Thousand miles of wind

17 Apr 2012 05:56 AM
The past two days have seen quite a bit of wind with high wind warnings and wind advisories issued by the National Weather Service. The featured map presents a crude calculation of the amount of air that passed by an observation station as expressed in miles of wind. As in your car, the distance traveled is simply the product of your speed and the time you traveled at that speed. This calculation is shown in the featured map with some locations over 1,000 miles in the past two days. More gusty winds are expected today.

Voting:
Good: 34
Bad: 6

Tags:   wind  


Windy Days

28 Nov 2011 05:49 AM
Since setting record high temperatures on Thanksgiving, our weather has been on the windy side with wind gusts measured above 30 mph each day since somewhere in the state. The featured chart presents the climatology of having one or more hours of wind observations at or above 30 mph for each day of the year. The annual signal is clear with these events more limited in the summer and peaking during the transition seasons of spring and fall. There are some localized peaks due to peaks in thunderstorms and strong winter storms.

Voting:
Good: 14
Bad: 2

Tags:   wind  

Wind components

09 Sep 2010 06:01 AM
The wind speed and direction can be broken into two components. These are a south to north (v wind) and west to east (u wind) component. [Those of you that failed geometry may wish to vote bad now]. The featured graph presents the daily averaged u and v wind speed component. This chart shows a clear annual cycle. Outside of the summer months, the jet stream is often nearby and tends to help promote dominant westerly winds. The v winds show us the dominant air temperature advection regimes with northerly (negative v values) during the winter time and warm southerly (positive v) in the summer time. September is shown as a transition period with westerlies increasing and southerlies decreasing.

Voting:
Good: 43
Bad: 6

Tags:   wind   climate  


As windy as it has been all summer

31 Aug 2010 06:00 AM
Sustained wind speeds on Monday were some of the strongest we have seen since early May as shown by the featured image. The black line represents climatology and nicely shows the yearly minimum in winds during the early part of August. Wind speeds will increase as surface temperature gradients become stronger during the spring and fall seasons. Thunderstorms are back visiting the state this morning with more expected into Thursday.

Voting:
Good: 22
Bad: 7

Tags:   2010   wind  


Wind reliability

07 Jan 2009 06:18 AM
Continuing in the series of climate features, today's plot is of the hourly frequency of an observed 10+ mph wind speed by month based on archived data from Des Moines. Those of us that live in Central and Northwest Iowa notice the many wind farms that are being built. Obviously, these turbines need reliable wind speeds to generate power. This plot indicates that outside of the afternoon hours in the spring and fall, having 10+ mph winds is roughly a 50% or lower chance on a daily basis.

Voting:
Good: 17
Bad: 5

Tags:   climate   wind  


Hourly wind climatology

03 Dec 2008 06:17 AM
The featured plot continues the series of hourly climatology plots. This plot is of average hourly wind speeds by hour and by month. The windiest time of year appears to be 4 PM in April and the least in the early morning in August. This plot nicely shows two maximums in the spring and fall. These are a result of the season transition periods as warm and cold air fights over Iowa! Large temperature gradients result in stronger winds.

Voting:
Good: 18
Bad: 14

Tags:   climate   wind