Weather Prediction

                Predicting the weather that is coming your way has a lot to do with measuring the weather today. Changes in temperature, pressure, humidity and wind speed are measured not only from weather stations on earth, but also by satellites circling the earth. There has consistently been atmospheric satellite data about our weather since 1971, so weather prediction has had very good data since then. The National Weather Service uses two different kinds of satellites to observe the weather from above. There are two polar orbiting environmental satellites that orbit 360 degrees from north to south and make a complete orbit of the earth every 1.5 hours. This gives a view of world weather and helps predict the 5 to 10 day forecast. These satellites orbit at an altitude of about 833 km (517 miles) above the earth’s surface. In addition, there are two Geostationary Operational Environmental Satellites that orbit at a much higher altitude (35,800 km or 23,300 miles above the equator) keeping pace with the earth’s rotation, so they can take pictures every 15 to 30 minutes of the same areas of the western hemisphere (North and South America). These pictures provide a birds eye view of potential storms and help forecasters monitor stormy weather.

In addition, since 2006, the COSMIC satellite program has used a network of 6 satellites to measure the conditions in earth’s atmosphere and ionosphere (100 - 500 km from the earth’s surface). The idea behind this system is that Global Positioning Signals (GPS) in the radio frequency range are bent by the atmosphere. The degree of bending depends on the temperature and humidity of the atmosphere. So by knowing the position in orbit that the signals are sent from and the positions on earth where the signals are detected, a grid of weather data can be calculated with very high accuracy. More information about the GPS satellites is available from the Earth Observation Resources website, including what radio frequency bands are used (S- and L-band), how many observations are made daily (1500 - 2,000 Radio occultation (RO) measurements per day), and what other sensors are available on the satellites. A UV spectrophotometer (Tiny Ionosphere Photometer) detecting oxygen ions at 135.6 nanometers helps determine the electron density of the atmosphere. It measures the naturally occurring nighttime emission of oxygen ions combining with electrons. Electromagnetic measurements are also taken using a Triband Beacon (TBB) transmitter, which measures the total electron content along a line of sight from the satellite to the receiving station on earth. The three transmitters operate in the VHF, UHF and L-band frequencies (150, 400 and 1067 MegaHertz, respectively).  

The COMET Program is part of the University Corporation for Atmospheric Research's (UCAR's) Community Programs (UCP) and is sponsored by NOAA's National Weather Service (NWS), with additional funding by:

So what does a weather station on earth look like? This is a picture of a weather station from the Utah State University, showing temperature sensors shielded from the sun, pressure sensors, an anemometer for measuring wind speed , a rain gauge and other instruments.

Spectrum News also has an article about how electricity companies in California are installing new weather stations to identify conditions which indicate a danger of wildfires, with the idea that they can shut off the electricity if conditions become very dangerous.

Weather can be affected by changes in the ocean surface temperatures. The Pacific Ocean normally has warmer temperatures in the West near the equator and cooler temperatures toward the California coast and Mexico. According to the American Geosciences Institute:

This helps to generate heavy rains over southeastern Asia and northern Australia and keeps parts of Pacific coastal South America relatively dry. This “normal” pattern of Pacific sea surface temperatures is disrupted periodically by El Niño and La Niña, naturally occurring climate phenomena that occur roughly every 3-7 years]. El Niño (the warm phase) and La Niña (the cold phase), typically last for 9-12 months each, but in rare cases can last over multiple years.

To see the temperature differences that affect the weather, you can look at historical data going back to 1950 on the National Weather Service website. The list the difference in average ocean surface temperature when compared to the normal temperature for that time of year. The peak high temperatures in the Pacific Ocean occur between April and July. To see a graph of the 30 year average temperatures used for comparison in the Oceanic Nino Index, check out this graph at the National Weather Service Climate Prediction Center.

The graph below from Columbia University shows that we are in the middle of a La Nina or cooling season and seems to predict a transition to a more neutral forecast later in the year.

Pressure can also have a significant effect on weather. Low pressure systems typically accompany rainy or stormy weather, while high pressure areas are usually associated with dry, sunny weather. Let’s take a look at a map of barometric pressure.

This image has very accurate pressure levels coded according to the last 3 digits of accuracy, but normally pressure maps have lines drawn connecting locations that have similar barometric pressure to show areas of low pressure and higher pressure.

To learn more about weather from the South Carolina school system, check out this website for students.

You can learn a lot more about how winds are moved by different forms of pressure at this Eastern Illinois University website.

The following map shows several high and low pressure areas and notes on how to interpret that information from the University of British Columbia website on how to read weather maps.

Hurricanes

                According to the National Oceanic and Atmospheric Administration (NOAA), most hurricanes occur during August and September, but the hurricane season starts in the beginning of June and ends at the end of November. Hurricanes usually begin as tropical cyclones, forming over the warm waters in the Atlantic Ocean, Caribbean Sea and the Gulf of Mexico. Some also form in the Eastern Pacific Ocean near Central America.

https://www.nhc.noaa.gov/climo/

For a more international view of hurricanes take a look at the following map and explanation of international waters where hurricanes occur.

An Australian region tropical cyclone is a non-frontal, low-pressure system that has developed, within an environment of warm sea surface temperatures and little vertical wind shear aloft in either the Southern Indian Ocean or the South Pacific Ocean.[1] Within the Southern Hemisphere there are officially three areas where tropical cyclones develop on a regular basis, these areas are the South-West Indian Ocean between Africa and 90°E, the Australian region between 90°E and 160°E and the South Pacific basin between 160°E and 120°W. The Australian region between 90°E and 160°E is officially monitored by the Australian Bureau of Meteorology, the Indonesian Meteorology, Climatology, and Geophysical Agency, and the Papua New Guinea National Weather Service and, while others like the Fiji Meteorological Service and the United States National Oceanic and Atmospheric Administration also monitor the basin. Each tropical cyclone year within this basin starts on 1 July and runs throughout the year, encompassing the tropical cyclone season which runs from 1 November and lasts until 30 April each season. Within the basin, most tropical cyclones have their origins within the South Pacific convergence zone or within the Northern Australian monsoon trough, both of which form an extensive area of cloudiness and are dominant features of the season. Within this region a tropical disturbance is classified as a tropical cyclone, when it has 10-minute sustained wind speeds of more than 65 km/h (35 mph), that wrap halfway around the low level circulation centre, while a severe tropical cyclone is classified when the maximum 10-minute sustained wind speeds are greater than 120 km/h (75 mph).

https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/hurricanes/location

You can also learn a lot more about tropical cyclones at the Comet Program educational website:

You may also want to read more about some of the most famous hurricanes and how good the weather prediction was at the time. Here are some historic hurricanes.

Cape May Hurricane of 1821: Landfall Near Cape May, NJ as a Major Hurricane on September 3, 1821. Wind Gusts Over 200 mph with Hurricane Force Winds as Far West as Philadelphia,PA!

1900 The Great Galveston hurricane, known regionally as the Great Storm of 1900, was the deadliest natural disaster in United States history and the fifth-deadliest Atlantic hurricane overall.

Chesapeake Bay Hurricane of 1933: Rare Hurricane to Strike Mid-Atlantic. Cat 2 Storm that Made Landfall near NC/VA Border on August 23, 1933. Significant Damage in VA/MD/and DE.

Hurricane Alma: Landfall on Florida Panhandle on June 7, 1966. Earliest Hurricane Landfall on Record in the United States. Wind Gusts over 120 mph in the Dry Tortugas.

Hurricane Inez: Known as the “Crazy One.” Erratic Path From Caribbean Eastward to Florida Then Back Westward to Mexico. Peaked as a Category 4 Storm. Hurricane Inez was a powerful major hurricane that affected the Caribbean, Bahamas, Florida, and Mexico in 1966. It was the first storm on record to affect all of those areas.

1983 Hurricane Alicia

1988 Hurricane Gilbert

1989 Hurricane Hugo

1992 Hurricane Andrew

1999 Hurricane Floyd

2003 Hurricane Isabel – landfall in North Carolina

Hurricane Charley 2005

Hurricane Dennis (2005): In 2005 Dennis Was the Strongest Atlantic Hurricane to Form Before August. Made Landfall on Cuba as a Category 4 Storm and Florida as a Category 3 Storm.

Hurricane Katrina was a large Category 5 Atlantic hurricane which caused over 1,800 deaths and $125 billion in damage in August 2005, particularly in the city of New Orleans and the surrounding areas. It was at the time the costliest tropical cyclone on record, and is now tied with 2017's Hurricane Harvey.

Hurricane Irene 2011

Hurricane Sandy was the deadliest hurricane of 2012 and one of the most destructive hurricanes in history to hit the United States. Toward the end of October 2012, Hurricane Sandy plowed through the Caribbean — killing 75 people before heading north. As it approached the East Coast, it produced the highest waves ever recorded in the western Atlantic, causing devastating storm surge and floods throughout coastal New York and New Jersey. At one point, Sandy engulfed a swath of 800 miles between the East Coast and the Great Lakes region.

Also called Superstorm Sandy, it caused $70.2 billion worth of damage, left 8.5 million people without power, destroyed 650,000 homes, and was responsible for the deaths of at least 72 Americans.

Hurricane Harvey 2017

Hurricane Michael 2018

Much of the math associated with weather prediction is complicated and takes place on supercomputers with lots of experts analyzing the data. It would be great if we could someday simplify the process of predicting the weather to be prepared for what is coming.