To complement the Daily Weather Summary for Monday, 5 September 2011


NOTE: This document is a repeat of that appearing as a Supplemental Information File for 29 August 2011.

Welcome to AMS Weather Studies! You are launching on a study of the earth's atmosphere, focusing upon a variety of physical processes in the Earth system that we commonly associate with weather. This unique course focuses on current weather events as a vehicle for understanding processes such as the flow and transformations of energy and water substance into and out of the atmosphere. Throughout this learning experience, you will be using the AMS Weather Studies website to access and interpret a variety of environmental information, including recent observational data. This Supplemental Information provides a brief tour of the features of this AMS Weather Studies website.

The first section of this home page is titled Learning Files, which contains the Daily Weather Summary, the Supplemental Summary and Weekly Weather and Climate News. The Daily Weather Summary is posted each weekday morning during the semester and contains a description of the current and recent weather features across the United States, Puerto Rico, and the Virgin Islands. Reference is given to features on the previous evening's weather maps, permitting you to inspect the map features as you read the summary. Supplemental Summary files, posted several times per week as appropriate, are files that contain interesting weather-related features, such as the occurrence of a White Christmas, or lengthier descriptions of how to decipher a surface weather map. The Weekly Weather and Climate News includes links to various current news items that pertain to weather and climate issues or to events that occur around the world that are not typically associated with events covered in the Daily Summary.

The last part of the Learning Files section is the Current Weather Studies, which contains links to the two electronic files that are delivered each week. CWS A is posted on Monday of each week, while CWS B is placed online on Wednesday. As many as three images may accompany each of these weekly Investigations. Click the appropriate links to download and print these electronic components of the investigations and their response forms.

The body of the AMS Weather Studies website provides links to a variety of current weather maps, weather data in text format and a selection of radar and satellite images. Extra information, such as blank maps and a key to weather map symbols, are also available. Let's take a quick tour to become more familiar with the AMS Weather Studies website.

Since we live on the Earth's surface, we are most interested in the weather that is occurring within a short vertical distance from the surface, typically no more than 10 meters (30 feet). Under Surface, click on Isobars, Fronts, Radar and Data. This image is a current weather map is a depiction of the weather across the continental US, with weather data plotted for a few selected locations, isobars (which represent lines of equal air pressure), fronts and areal coverage of precipitation and its intensity from weather radar. You can retrieve a variety of other depictions of the surface weather. Within the next two weeks, several Supplemental Summary files will be made available that will help in your interpretation of the weather map.

We often find it informative to monitor the extent, intensity and progress of precipitation as it moves across the nation. Weather radar is a tool that permits us to detect this precipitation. Under Radar, click on Latest Radar Animation. A 12-hour loop of radar images can be run, showing the movement of areas of precipitation as detected by the National Weather Service radar units across the country.

Likewise we can track the motion of clouds from the perspective of a satellite platform located in a geosynchronous orbit that is located approximately 35,000 km above the earth's equator, which is at a distance where the forward motion of the satellite is synchronous or appears stationary with respect to a point on the earth's surface. Under Satellite, click on Latest IR Animation to access a loop of images collected from infrared radiation sensors on geosynchronous satellites that show the evolution and movement of cloud patterns across the country.

Although we obtain much information from weather observations made at the earth's surface, meteorologists have been using instrumented weather balloons to obtain a three dimensional picture of the atmosphere up to altitudes exceeding 20 km. Under Upper Air, click on 500 mb - Contours, Isotherms & Data. The accompanying chart portrays the temperature, humidity and wind conditions that the weather balloons collected within the last 12 hours at an altitude where the air pressure (500 millibars or mb) is approximately one-half that at sea level (approximately 1000 mb), or at an altitude of approximately 5.5 km. Later in the semester, we will take time to explain this chart, along with those at 850 mb (or an altitude of approximately 1.5 km), 700 mb (3 km) and 300 mb (10 km).

"The National Weather Service (NWS) provides weather, hydrologic, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy [from NWS Mission Statement]." To fulfill this responsibility, NWS generates and issues weather forecasts from several numerical weather prediction models interpreted by highly trained and experienced Meteorologists. When necessary, the NWS will issue weather advisories, watches or warnings to alert the public of a possible or occurring weather event that could be harmful or even deadly. Under Watches, Warnings, Advisories and Forecasts, click on Current NWS Weather Watches and Warnings, which will launch the official NWS page that has an interactive map of the continental US with site specific displays of active watch, warnings, advisories and short term forecasts. By the end of this course, you will become sufficiently familiar with the terminology that is used to alert the public of adverse weather.

Weather represents a snapshot of the current state of the atmosphere, while climate represents a perspective of the longer-term state of the atmosphere, extending from months to decades, or longer. Climate typically involves interaction between the earth's atmosphere and the underlying surface, including both continent and ocean. As we will see during the sixth week of this course, the water or hydrologic cycle is an important factor that keeps our planet habitable. Unfortunately, variations in the hydrologic cycle over a region can result in disastrous flooding or drought. Under the Climate heading, click on Drought Monitor, which displays a map of the current drought conditions across the nation as prepared by the National Drought Mitigation Center.

Extras include a variety of information that should be of use to you. Click on Weather Map Symbols to see the variety of symbols that appear on the surface weather map.

Take a few minutes when you have time to browse the other data and information sources available via the AMS Weather Studies website. You should "bookmark" ("favorites") this page on your computer. Return frequently to learn more about the current weather resources available through AMS Weather Studies.

Return to the Monday Daily Weather Summary

Return to AMS Weather Studies website

Prepared by Edward J. Hopkins, Ph.D., email
© Copyright, 2011, The American Meteorological Society.