In 1999 I visited the cities of Wichita, Tulsa and Oklahoma City (I
was vacationing and visiting my bro and sis in Tulsa)--taking time
to view and photograph the tornado damage from the outbreak on May
3, 1999. What I noticed most was that the largest tornadoes all
visited, almost exactly, the Southern sector of the urban areas.
This was beyond random probability--if you merely take ten degrees
of arc out of 360 and cube it, the chance of this happening randomly
is in the 10s of thousands--and that is with the further assumption
that the big cities all get hit, and that is what Wichita, Tulsa,
and OKC are to that region. This couldn't have happened by chance.
The next several months I looked at urban heat island studies and
read everything I could on the subject. To my surprise, Atlanta had
a study for the olympics that showed that there was an increased
chance of thunderstorms in the afternoon, and that the storms had a
tendancy . . . to go to the Southern sector! That summer (1999) I
watched a number of storms in urban centers on radars from TWC and
noticed the same thing reoccurring in cities like Pheonix, the
greater Salt Lake City area, Kansas City, and so forth.
Now someone has done an interesting temperature profile that I would
like to share:
However, I want to make a few things clear. IMHO, it isn't so much
CO2 as a GHG that is working its wonders here. CO2 is known to be up
to DOUBLE in urban areas (about 550 ppm) from the cars and
industrial activity. That said, this kind of concentration of CO2
will change the ACIDITY or pH of the water vapor in the air.
Further, water from suburban settings, beit from sprinkling and
lawns or from water vapor from car exhaust, is going to have a
profound ELECTRICAL meaning--making for a greater tendancy for
electrons to be able to move from ionosphere to ground opposing fair
weather proton movements to ground.
The metal of cities, destributed broadly, will offer a better
dielectric. Finally, the asphalt roads and tar roofs offer black
albedo surfaces--absorbing the light energy and turning it to heat.
NASA has some pretty neat pictures of Salt Lake City showing that.
All and all, it means that there is a greater chance in the cities
for convection and cirrus enhancement--that the heat gets trapped in
the cities and this results, with ambiant winds and EMF conditions,
to bring greater probabilities to the urban areas for warmer, wetter
conditions, and specifically, w/ coriolis forcings, produces a
greater chance of rain in the southern sectors of urban areas.