Welcome to Our Learning Center for a Bit of Fun and Trivia

Updated 7/10/2006

Estimating Winds and Rain

15-25 mph: raises dust and loose paper; small branches move
20-25 mph: small trees begin to sway
25-30 mph: large branches in motion; whistling in wires
30-40 mph: whole trees in motion; difficulty walking against the wind
40-45 mph: breaks twigs of trees; impedes progress
45-55 mph: breaks small tree branches; slight structural damage
55-65 mph: breaks large tree branches; pushesover shallow rooted trees; considerable structural damage to chimneys, TV antennas, etc
65-75 mph: widespread damage
>75 mph: severe damage and destruction

Moderate: 0.11 inches to .30 inches per hour or more than .01 to .03 inches in 6 minutes.
Puddles form rapidly. Sound on roofs ranges from swishing to gentle roar.

Heavy: More than 0.30 inches per hour or more than .03 inches in 6 minutes. Rain seems to fall in sheets. Visibility is greatly reduced. Sound on roofs resembles roll of drums or distant roar.

Barometers and how to Calibrate them
Calibrating barometers has been a recent subject here at Skywarn. To make a long story short your barometer should be set to the nearest official reporting station to you. In the case of Orange County there are 3 stations. The links to these stations are below. Simply find the station nearest you and calibrate yours to it. The best time to do this is when weather conditions are fairly neutral meaning no low or high pressure systems are moving over our area. Also remember that altitude makes NO difference. You can be at sea level or 2000 ft high. This is called corrected readings for altitude. Click on the first link below on a more in depth article on barometers. If you have any questions please use the contact page and we will get back to you.

Barometer Article
{Click Here}

Links to Barometer Calibrations

Remember to use the Sea Level Pressure in Millibars, not Station pressure !!!!
then convert to inches.

Fullerton Airport
Los Alamitos Naval Air Station
John Wayne Airport

What are Heating Degree Days and Cooling Degree Days.
Why do we want or need to know the number of "degree days?"

See below for answer

NWS School

Below are links to Weather learning materials

Jet Stream
A free NWS online weather school
(for class matrix, click here)

Skywarn Spotter Certification Course
(NWS San Diego)

Pineapple Express
What is it and where does it come from ????

Otherwise know as intraseasonal oscillations to heavy precipitation events in the western U.S. the term Pineapple Express is being talked a lot about lately. Click on the link below to learn more.

Pineapple Express



A "degree day" is a unit of measure for recording how hot or how cold it has been over a 24-hour period. The number of degree days applied to any particular day of the week is determined by calculating the mean temperature for the day and then comparing the mean temperature to a base value of 65 degrees F. (The "mean" temperature is calculated by adding together the high for the day and the low for the day, and then dividing the result by 2.)

If the mean temperature for the day is, say, 5 degrees higher than 65, then there have been 5 cooling degree days. On the other hand, if the weather has been cool, and the mean temperature is, say, 55 degrees, then there have 10 heating degree days (65 minus 55 equals 10).

It is a good way to generally keep track of how much demand there has been for energy needed for either heating or cooling buildings. The cooler (warmer) the weather, the larger the number of "heating (cooling) degree days"... and the larger the number of heating (cooling) degree days, the heavier the demand for energy needed to heat (cool) buildings.


Rip Currents !!!!!!!!!!
Below is a link to Ocean Rip Current information

Rip Current Safety