Author Topic: Dew Points?  (Read 3432 times)

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Offline Thor

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Dew Points?
« on: November 16, 2009, 05:49:06 PM »
What is the significance of telling people the dew point?
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Offline djones520

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Re: Dew Points?
« Reply #1 on: November 16, 2009, 05:51:52 PM »
Telling the general civilian population, not a lot.
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Offline thundley4

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Re: Dew Points?
« Reply #2 on: November 16, 2009, 05:54:51 PM »
I haven't a clue, but during the course of the day, the dew point will change, based on the factors affecting it.

Offline JohnnyReb

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Re: Dew Points?
« Reply #3 on: November 16, 2009, 06:10:27 PM »
Fog.
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Offline djones520

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Re: Dew Points?
« Reply #4 on: November 16, 2009, 06:23:12 PM »
Fog.

It isn't always an indicator of fog though.  I've seen a 0 degree Temp/Dew Point spread without any fog many times.
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Offline jinxmchue

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Re: Dew Points?
« Reply #5 on: November 16, 2009, 07:12:19 PM »
The dew point is important for airplane pilots to know.  The dew point can also give you a general idea of what the day is going to feel like - humid in the summer or dry in the winter.

Offline thundley4

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Re: Dew Points?
« Reply #6 on: November 16, 2009, 07:15:28 PM »
The dew point is important for airplane pilots to know.  The dew point can also give you a general idea of what the day is going to feel like - humid in the summer or dry in the winter.

Humidity is relative.

Offline Thor

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Re: Dew Points?
« Reply #7 on: November 16, 2009, 07:49:58 PM »
The dew point is important for airplane pilots to know.  The dew point can also give you a general idea of what the day is going to feel like - humid in the summer or dry in the winter.

RH and barometric pressure always figured into my dispatch figures when I worked for the airlines. I don't recall the dew point making any difference. I had been told in the past that the dew point was the coldest it could get like for overnight temps.
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Offline jinxmchue

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Re: Dew Points?
« Reply #8 on: November 17, 2009, 07:58:39 AM »
RH and barometric pressure always figured into my dispatch figures when I worked for the airlines.

Sounded like it was more for non-commercial pilots, particularly those who fly smaller, non-sophisticated planes.

Offline djones520

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Re: Dew Points?
« Reply #9 on: November 17, 2009, 08:51:27 AM »
RH and barometric pressure always figured into my dispatch figures when I worked for the airlines. I don't recall the dew point making any difference. I had been told in the past that the dew point was the coldest it could get like for overnight temps.

And RH is determined by the Dew Point.  When those observations are taken, we don't put RH into them.  We just put Dew Point into it, then the RH is calculated later on.  DP can have an impact on pressure, but many things can as well.

The actual temperature can never go below the dewpoint, that's right.  But the dew point is no set gaurantee that the temp will stop there as it's dropping.  It may hit saturation, then then both will start dropping even more.
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Offline Wineslob

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Re: Dew Points?
« Reply #10 on: November 17, 2009, 10:56:10 AM »
I can't remember the calc's right now, but when we choose the refrigerated air drier for our compressed air system the DP (average for our area) was an important factor. It effects the driers ability to remove water from the system.
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Offline Chris_

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Re: Dew Points?
« Reply #11 on: November 17, 2009, 11:27:03 AM »
As someone above mentioned, it is important for pilots to know the dewpoint in order to be aware of the possibility of icing during flight.....although the temperature at the surface may be well above freezing, it wil not necessarily be so at altitude, and if the temperature and dewpoint are close together, a couple of thousand feet in altitude can place you in icing conditions..........with potentially disastrous results.

Weather forecasters use it more universally than RH for purposes of evaluating changing conditions in airmasses for modelling purposes........dewpoint is a much more specific measurement for atmospheric sounding purposes.

It is also useful in agricultural applications in determining the potential moisture content in grain crops if it is plotted for a specific area over a period of time, particularly at this time of the year (harvest time).

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Re: Dew Points?
« Reply #12 on: December 28, 2009, 07:34:47 PM »
I know that bubble heads were really concerned about it.

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