Tuesday I discussed weather balloons. Now I am stepping deeper into the complexities of weather forecasting.
The information derived from the radiosonde attached to a weather balloon is transposed onto a skew t plot as seen below.
As a radiosonde balloons ascends, it records the temperature and relative humidity at certain prescribed pressure levels (called the mandatory levels) and anytime a significant change occurs in the temperature, humidity, or wind.
Typically, a radiosonde observation is complete when the balloon, carrying the radiosonde, bursts and begins to descend. At that time the data is compiled into a series of five-digit groupings containing temperature, dew point depression and wind speed/direction for mandatory and significant levels. This data is plotted onto a skew-T.
The five-digit coded radiosonde observation is complicated to decode and plot onto a Skew-T diagram. As such, there are several private weather vendors and universities who have written programs to decode and plot (or redisplay the info in a tabular format) these observations. A simple Internet search for “atmospheric soundings” will provide you with several choices.
There are two basic lines plotted on a Skew-T from which we can derived much information. These represent the dew point which is calculated from the relative humidity (in blue, left line) and air temperature (in red, right line).
While it is generally true that the air temperature decreases with height, it is readily seen that this decrease is not uniform nor is it consistent. There may be several places where the air temperature remains the same or increases with height. These particular places are called ‘temperature inversions’ where the normal temperature decrease is ‘inverted’ and the temperature will increase with height.
Another common characteristic of radiosonde soundings is the location of the tropopause. The tropopause is the boundary between the troposphere and stratosphere and is also indicated by a large temperature inversion.
The dew point line will be the most ‘wiggly’ as the radiosonde ascends through intervening pockets of moist and dry air. At each level on the Skew-T, the closer the dew point is to the temperature, the higher the relative humidity is at that level. The dew point will occasionally equal the air temperature and will be seen by the intersection of both lines.
The other piece of information plotted on a Skew-T is the wind speed and direction. This info obtained as the radiosonde is tracked using GPS during its ascent. The wind speed and direction is reported for the same mandatory pressure levels with additional required elevations above sea level and for any significant changes in speed or direction.
Across the country and around the world, radiosondes sample the atmosphere twice daily providing answers concerning the state of the upper air.
Below are the soundings for Gaylord and Detroit for this morning: (to view full size – right click and view image).
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There is a chance of showers later today, perhaps a few rumbles of thunder. Friday through Sunday we should dry out before the pattern returns to rain once again.
Seven Day Forecast
Pollen Forecast
Just another dreadful cool, wet Spring day in MI!! Incredible!
Wasn’t bad here. Hit 57° and the sun peeked out a little bit this afternoon. Still lots of standing water around. Chance of rain most days over the next week will not help to dry things out.
A storm free, cold 2019…life in the Southern Arctic. Rumor has it that MI my have been covered by ice at one time or another. Lucky us…witnesses to the next cycle. Do you best to stay warm.
Yes we might be tending into an extended cool pattern that could last years!
The UP had a May snow storm yesterday!! Here are some snow fall amounts Marquette 5.4” (new record for the date old record was 3.3” set in 1976) Painesdale 5.2”, Michigamme 4.5”, Champion and Laurium 4.0”, Ishpeming, Calumet and Negaunee 3.0” For the winter season Marquette is now at 227.1” and at Tamarack the reported total there is 357.2” At Marquette that 227.1” is the most since 2007/08 when 246.0” fell and the record at Marquette is 319.8” in the 2001/02 season.
Slim
More confirmation that this has been a very cold and snowy winter/spring! Some people need to face reality!
MV is now getting into the area of forecasting that i really do not understand. But it is part of the every day tools that are used,
Slim
Agreed
Let’s review the facts!
1. April was below normal with temps and above normal snowfall!
2. We have seen 4 months in a row with below normal temps!
3. We have seen many months in a row of above normal snowfall!
4. Clearly we are in a below normal temp pattern this year!
5. Winter is the best season!
6. MV and Slim rock!
7. Facts speak truth to power!
8. Thunderstorm drought continues..INDY!
9. Tigers stink
10. It has been a cloudy spring.
11. Winter is over its time for summer
Slim
12. Lol..INDY!
I agree with all of the additions!