Okay, I'm convinced...but also confused.  Does this mean that when it
looks or feels like it is too cold to snow, it won't snow, but its
actually because of something else?  So that in effect one is correct,
it is not going to snow, but for the wrong reason?

And of course it appears that my assertion that the lower moisture
capcity of the cold air is not the correct reason, but sure makes sense
and is a lot easier to explain.  On the other hand, maybe the easiest
thing to do is simply state that its too cold to snow and leave the
science to someone who is more interested in why than whether or not it
will snow.

Now that I've written all of this I'm really confused.  I'd better get
back to work when I get paid for being confused.

-jc

On Jan 16, 2004, at 1:42 PM, Bruce Marcham wrote:

> A ways back someone asked if it could be "too cold to snow" so I
> decided to ask Google...
>
>
>>
> From METEOROLOGIST JEFF HABY
> http://www.theweatherprediction.com/habyhints/222/
>
> One phrase that is heard time to time is that, "it is too cold to snow
> today". In actuality, earth's atmosphere is not too cold to snow but
> rather it is "too dynamically stable to snow". Dynamic stability may
> be present due to low-level cold air advection, a lack of upper level
> divergence, and/or a lack of low level convergence. Also, if dynamic
> lifting does occur it may not produce precipitation that reaches the
> surface due to low RH values in the lower troposphere.
>
> The ingredients for snow are: (1) a temperature profile that allows
> snow to reach the surface, (2) saturated air, and (3) enough lifting
> of that saturated air to allow snow to develop aloft and fall to reach
> the surface. In a situation when it is said "it is too cold to snow"
> there is in reality not enough lifting of air that causes snow to
> reach the surface.
>
> The phrase "it is too cold to snow today" probably originated as a
> misapplication of the relationship between temperature and the maximum
> amount of water vapor that can be in the air. When temperature
> decreases, the maximum capacity of water vapor that can be in the air
> decreases. Therefore, the colder it gets the less water vapor there
> will be in the air.
>
> Even at very cold surface temperatures significant snowfall can occur
> because: (1) intense lifting can produce significant precipitation
> even at a very low temperature, (2) the temperature aloft can be much
> warmer than the temperature at the surface. The relatively warmer air
> aloft can have a larger moisture content than air in the PBL, (3)
> Moisture advection can continue to bring a renewed supply of moisture
> into a region where lifting is occurring, (4) Even at very cold
> temperatures the air always has a capacity to have some water vapor.
>>
>
> Having an interest in weather stuff I did a little more searching on a
> phenomenon called "hoarfrost" which is when ice crystals form on tree
> branches.  I spent a day with some Civil Air Patrol radio geeks who
> got into giggles about the word when we were helping out with a
> crosscountry ski race up on the Tug Hill Plateau one very cold winter
> day.
>
> This site has some good info if you're into cold weather:
>
> http://nsidc.org/arcticmet/
>
> Bruce
>
> --
> To terminate puerile preservation prattling among pals and the
> uncoffee-ed, or to change your settings, go to:
> <http://maelstrom.stjohns.edu/archives/bullamanka-pinheads.html>
>

--
To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
<http://maelstrom.stjohns.edu/archives/bullamanka-pinheads.html>