Tuesday Morning

Good Morning Augusta.
This morning it is clear, then partly cloudy. High of 82F. Winds from the
West at 5 to 15 mph. Chance of rain 20%.
Tonight it will be clear with a chance of rain. Low of 55F. Winds less than
5 mph. Chance of rain 20%.
The readings outside at this moment taken from my own instruments are:
a relative humidity of 58% with a Dew Point of 52.8º F.
The temperature is 68.2ºF.
Presently we have Southwest winds between 4.0 MPH and 6.4 MPH.
Our Barometric pressure is 29.93/HPA 1013.5 and rising with a weather
graphic indicating sun.
UV is 3 out of 16, sunset will be at 8:23 PM with Moon Rise at 11:45 p.m.
Eastern Daylight Time, and the moon phase is Waning Gibbous.
For the aviators out there: Raw METAR –
METAR KAUG 101153Z AUTO 28007KT 10SM CLR 18/08 A3002 RMK AO2 SLP164
T01830083 10183 20144 52012
We had no precipitation overnight in this area.
Visibility is 10.0 miles / 16.1 kilometers with a nice, clear ceiling.
Many of you may notice that weather forecasters are slowly cutting back on
how often they refer to humidity and increasingly use the "Dew Point" form
of measurement in reporting how much moisture is in the air.
For those of us who were raised in the era of humidity, shifting to Dew
Point is not very logical. So below is another explanation of what Dew Point
means compared to "humidity".
Q: Is dew point or relative humidity a better indication of how humid the
air feels? My guess is it's relative humidity. Also is there much variation
between the dew point temperature from day to day?
A: Dew point is by far the better measurement of how humid the air feels.
This is the case because dew point is a measurement of how much humidity is
in the air, no ifs, ands or buts about it. Relative humidity tells you how
much humidity is in the air compared with how much can be in the air at the
temperature the air happens to be when you measure it.
This means that the relative humidity goes down as the temperature goes up
even though the amount of water vapor in the air (humidity) remains the
same.
To give you an idea of how this works, I used the Weather calculator on the
Web site of the National Weather Service office in El Paso, to calculate
some temperature, dew point, and relative humidity combinations.
If the temperature in the morning is 71 degrees, and the dew point is 70
degrees, the relative humidity would be 97% (rounded off). As the day warms
up the dew point would stay the same unless a new air mass arrived with
either more humid air or drier air.
Let's assume that this does not happen. If the air warmed to 95 degrees and
the dew point stayed at 71, the relative humidity would be 44% and the heat
index would be 101 degrees.
On a day like this, you'd feel sticky when you left your air-conditioned
house in the morning, and by mid afternoon, people would be walking around
saying things like, "Boy, it must be 95 degrees and 95 humidity."
No way.
The only way you'd ever see a temperature and relative humidity both of 95
would be if the dew point were 93 degrees. The only place you would find
that high a dew point outside a lab experiment would be some place like the
Persian Gulf.
A good general rule of thumb is that when the dew point is between 60 and 70
degrees F most people will think it's humid. When the dew point tops 70,
almost everyone will feel uncomfortably humid. When it tops 80, as it rarely
does anywhere in the USA, it's likely to set records.
As for day to day variation. The big variations come when a new air mass
moves in. Or, during the summer you could have the humidity (thus the dew
point) slowly increase if you have a steady wind from warm water, such as
the Gulf of Mexico, even though the weather map never shows a warm front
actually arriving.