This is part #2 of 3 parts to the PowerPoint presented in class on

Monday, August 5.

So, to reach maximum humidity on a hot day, we need 10 gallons of water to fill a 10 gallon

bucket. 100% humidity is 10 gallons of water, relative to a 10 gallon bucket.

How many gallons of water are needed to get 100% humidity on a cool day, where the bucket

is six gallons in size?

<we need just six gallons, because on a cool day it takes less water to fill the “bucket” to humidity saturation>

So, humidity is always relative to capacity.

How is a convective cell different from a lava lamp? <it really isn’t>

Or an orographic/mountain flow?

Convective Cell

Evaporation phase – hiding heat in vapor

Condensation phase – heat being released when humidity turns back into visible water

High and Low Pressure(cyclones & anti-cyclones)

All Four Types of Stormswarm & wet

are lighter thancool & dry Stormy side – rain/snow

Sunny or dry side

Cyclonic storm is counterclockwiseAnti-cyclone is clockwise and is usually sunny or clear

skies

Stormy

Which of these would experience clean air and rain versus sunny conditions with bad air quality?

Thunderstorm

What goes up must come down

If the front side of a stormy is rising air and release of heat for more rising air,

then . . . . .

The backside of a storm is descending air. On occasion, descending air can be concentrated into a high-speed ‘micro-burst’.

Micro-burstJune 2013 severe downdrafts in Taylorsville hit 70 mph

Frontal Storm Step-wise

Of the four storm types, frontal or wedge weather is the most prone

to violence and is a major source of precipitation in the mid-latitudes.

The United States is famous for ‘frontal/wedge’ storms. At least 90% of all tornadoes occur in the

U.S. “tornado alley”

Frontal Weather

Source: physicalgeography.net

High winds and heavy rain can develop as cold air helps warm air to rise and heat itself further by condensation

Ordinary Cumulus Clouds(rising air cools and condenses hidden heat comes back out with the water)

Rising air condenses out a cloud and warms itself for more rising

Descending air tends to show clear skies

Cumulus cloud building as rising air speeds up by re-heating itself.

There must be a lot of humidity (with hidden heat) in this area, because the cloud is building as it releases heat and water.

There must be a lot of humidity (with hidden heat) in this area, because the cloud is building as it releases heat and water.

Massive amounts of hidden heat come back out as air rises quickly. The release of latent heat causes even more rapidly rising air.

This rising air is “cyclonic” or turning counterclockwise as it rises.

Potentially deadly storm as vast heat comes out of ‘hiding’ – high wind as air rises very quickly.

Tornadoes can result when the Coriolis force causes rapidly rising air to turn counterclockwise as it rises.

If rising air accelerates to 60 mph . . . .

then wind along the ground must be going 150-200 mph in order to turn counterclockwise as it rises.

To “feed” a tornado with rising air, ground wind must be super-fast wind.

That is what causes so much tornado damage.

When rising air accelerates due to big difference

between cold/dry air and warm/wet air.

Source: MS Office freeware.

Lightning Moving air creates ‘static’ electricitySort of like storing energy in a battery

Lightning Discharging the battery to another cloud or to the ground

Drought – lack of expected precipitation

Can be ‘heat driven’or

Climate changeor

A “La Nina” condition (more about this later)

orNormal oscillations in weather

Page 70 – Heat WavesEurope 2003 – 35,000 deaths due to heat, 14,500 in France

The Summer of 2013 may go down in history as being a ‘heat wave’

year.

Let’s wait and see.

Would high air temperature tend to provoke more wildfires?

Hypothermia and Heat Stress

Humidity has a powerful effect when air is either hot or cold.

In between high and low, ordinary room temperatures don’t feel much different with higher or lower humidity.

So, swamp coolers work pretty well – the extra humidity from hiding heat does not carry a heat index penalty or a hypothermia penalty.

In extreme cold, the air can’t hold much humidity anyway, so only wind child is an issue, unless you fall into water.

Heat Stress Index

This chart does not include humidity, which in COOL air could cause hypothermia. That is because really COLD air can’t hold much humidity anyway.

Hail

Storms are low pressure events – rising air

Strong updrafts blow rain back up to where a new later of ice can freeze on it.

It falls again, only to be blown back up for yet another layer of ice.

Eventually, the ice pellet becomes baseball-size or even as big as a basketball before finally escaping the

updraft and melting somewhat as it falls to earth.

Hurricane (also called ‘cyclone’ or ‘typhoon’)

All storms involve rising air that turns counter-clockwise

U.S. tornado season starts earlier than hurricane season because land masses heat

up more quickly than do oceans, even as there is still cold air and even snow on the ground

nearby. That is a perfect combination for conflict.

Meanwhile, oceans warm more slowly and cool off more slowly, so it is almost winter

before hurricane season ends.

All storms involve counterclockwise rising air.

As rising air condenses out more water and re-warms itself, wind

speeds rise also.

Rising air can rise faster if cooler, dryer air is nearby - - something to

“push off of”

So, tornadoes and hurricanes often occur when an air mass with excessive

amounts of heat and humidity runs into an air mass with cool, dry air.

The heavier cool/dry air pushes under – helping the more buoyant warm/wet air to rise

even faster, causing even faster wind speeds that can eventually become a tornado or

hurricane of super-fast air that is “loaded” with excess heat and water that it can ‘blow off’

Tornadoes

U.S.A. has more than 90%Bangladesh hosts many of the remainder.

Why?

US Southeast ought to be a desert, but is warm/humid, flat country where c/d can mix with w/w

Tornado Alley is where cool/dry air from the north and west meets warm/wet air from the south and east.

Super-fast ground winds must ‘hustle’ to rise while also rotating counterclockwise.

KTVX, 2007, David Dingle

I-15 near Tremonton

Hurricanes

- Policy failures that provide false sense of security?

- Running out of the safest sites?

- Hurricanes include bands of strong thunderstorms, sometimes called ‘heat towers’ because of how much latent heat they carry to high altitudes

Hurricane can contain hundreds of thunderstorms and dozens of tornadoes

300-600 miles in diameter

Versus

¼ mile

How does a dust devil compare to a tornado?

Compared to a simple dust devil, hurricane storm surge has . . . . Water.

1. Low atmospheric pressure2. High wind

3. High waves (wind driven - upstream)4. Heavy rainfall (downstream)

All of these are driven by latent heat hidden in the atmosphere. When clouds form by rising, cooling air, latent heat is released along with water vapor,

adding “fuel” to the storm. Dust devils are only about rising hot air that cools and calms quickly with altitude.

Source: thatscienceguy.wordpress.com