[FRIAM] Metaphors and Meteorology

Mon Jun 14 16:41:28 EDT 2021

Well, to be honest, I have never known who they are written for.  

But if you are willing to look stuff up, they are a vast trove of information.

Nick 

Nick Thompson

 <mailto:ThompNickSon2 at gmail.com> ThompNickSon2 at gmail.com

 <https://wordpress.clarku.edu/nthompson/> https://wordpress.clarku.edu/nthompson/

From: Friam <friam-bounces at redfish.com> On Behalf Of Frank Wimberly
Sent: Monday, June 14, 2021 4:18 PM
To: The Friday Morning Applied Complexity Coffee Group <friam at redfish.com>
Subject: Re: [FRIAM] Metaphors and Meteorology

That's a report written for the general reader?!?

---
Frank C. Wimberly
140 Calle Ojo Feliz, 
Santa Fe, NM 87505

505 670-9918
Santa Fe, NM

On Mon, Jun 14, 2021, 1:09 PM <thompnickson2 at gmail.com <mailto:thompnickson2 at gmail.com> > wrote:

Dear Phellow Phriamers, 

After an ox-stunning spate of hot weather, we are now back in the 59 degree fog bank here in sunny Massachusetts.  I cannot go out in the garden, so you all are the “beneficiaries” of my being at loose ends. 

As one might expect, when Meteorology developed between the wars, it took on a military metaphor.  There were armies of warm and cold air that fought for control of the landscape.  Between them were “fronts” where warm air would liberate  the land only to be reconquered by the cold air.  The fronts were ideally thought of as sharp changes in temperature, dewpoint and wind direction accompanied by a fall and then a rise in pressure.  I used to draw weather maps as a kid from the station reports on SW radio, and I found it much harder to locate fronts than the metaphor allowed.  It seemed more like a contest between guerilla units than the advance and retreat of disciplined armies along a front.  In fact, when I wrote the weather book, I couldn’t find an archetypal weather map that demonstrated fronts cleanly, and so had to draw the fronts and then make up the observations to illustrate the concept.   

I read forecast discussions obsessively, partly for the science and partly because their language is so rich and tortured.  Talk about metaphors!  In any case, these discussions are becoming harder and harder to read purely in terms of military incursions at the surface and more and more a matter of upper=air fluid dynamics.   I thought perhaps that was because I have been living at 7000 for a year-and-a-half with more than the quarter of the atmosphere already below me.  

But now I am back in MA and the forecast discussions are still talking about upper air features as much as they are about surface ones. Below is a current discussion, marked up by me to translate some of the Jargon.  It is full of references to upper level events.  

Now here is my quandary.  Given Critchlow’s Law [LAYERS IN THE ATMOSPHERE DO NOT MIX [ but they can be STiRRED —NST]], how on earth do events in the upper atmosphere affect events in the lower atmosphere.   Think of those jet streams roaring along a 100 mph up at 30,000 feet.  They contain only 10 percent of the mass of the atmosphere.  How are we to thinking of them as affecting anything below them.   What metaphor is at work when we think of the ridges and troughs aloft as causing the highs, lows and front’s at the surface.  

Also, do jet’s use more fuel or less fuel when flying with a jet stream; on the one hand you would expect less because they are getting help from the wind; on the other you would expect less because the plane has to fly faster to stay aloft.  Or perhaps the same because the two factors compensate for one another? 

Anyway, here’s the forecast discussion, as annotated  .

Tuesday Night through Friday:

Rain from the daytime Tuesday period come to an end early Tues night. The vast majority of the mid to latter part of the workweek features really pleasant weather, under cyclonic flow <https://forecast.weather.gov/glossary.php?word=flow>  aloft (associated with an anomalously [= unusually]strong upper trough <https://forecast.weather.gov/glossary.php?word=trough>  over eastern CONUS <https://forecast.weather.gov/glossary.php?word=CONUS> ) and a surface ridge <https://forecast.weather.gov/glossary.php?word=ridge>  of high pressure. Cool pocket [= a layer of air over head that its unsually cool for its altitude]of air aloft and below-normal <https://forecast.weather.gov/glossary.php?word=normal>  850 mb <https://forecast.weather.gov/glossary.php?word=mb>  temps with strong insolation <https://forecast.weather.gov/glossary.php?word=insolation>  [= sunlight]support deep mixing [= when air is cool aloft and heated at the surface it tends to convect, and therefore to be stirred to the next layer of warmer air.]; fairly small thing but opted to lower dewpoints toward the 10th percentile NBM values each afternoon given the envisioned strong mixing. Expect mostly sunny skies with clear nights and fairly strong diurnal <https://forecast.weather.gov/glossary.php?word=diurnal>  ranges in temps.

By Friday, mid-level trough <https://forecast.weather.gov/glossary.php?word=trough>  [= a trough is a dip in the upper air flow, like the dip between two waves; the tops of the waves are called ridges]axis shifts offshore as geopotential heights [= a “height” is the altitude at which a particular pressure is reached. It is the weight of the atmosphere below that point. Think low pressure, roughly]transition to shortwave <https://forecast.weather.gov/glossary.php?word=shortwave>  ridging[= i.e., a teensy ridge]. Warming trend to temperatures then set to commence as well with 925 mb <https://forecast.weather.gov/glossary.php?word=mb>  temps upper teens to around 20C/850 mb <https://forecast.weather.gov/glossary.php?word=mb>   [= i.e. in the 3-5,000 foot range. This is very generally the top of the layer which interacts with the surface, but of course, for mother church members, it’s two to four thousand feet below the bottoms of their shoes. ] temps around the mid teens C <https://forecast.weather.gov/glossary.php?word=C> . Dewpoints [= the dewpoint is the temperature at which water vapor condenses. Low dewpoint air is dry air, and, therefore, heavier than wetter air around it. Since the body’s cooling mechanisms depend on evaporation, it is also “more comfortable to be in warm dry air than to be in warm wet air.  Think swamp coolers.]still look comfortable (mid to upper 50s) but will see highs in the interior push into the low-mid 80s.

Nick Thompson

ThompNickSon2 at gmail.com <mailto:ThompNickSon2 at gmail.com> 

https://wordpress.clarku.edu/nthompson/

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