UNIVERSITY PARK, Penn.--TV or radio weather reports, which tend to be somewhat regional, leave true weather aficionados unsatisfied. Now, "Hometown Weather" from the meteorology department at Penn State can give Pennsylvanians local, accurate, up-to-date weather information with a click of a mouse.
"Some other weather web sites use National Weather Service maps and interpretations by meteorologists," says Dr. George S. Young, associate professor of meteorology. "Our web page uses NWS data, but uses a computerized mesoscale weather model for its forecasts."
The weather model produces forecasts for a grid system of points every 20 miles. For the Philadelphia area, by moving the cursor only slightly, forecasts are available for Philadelphia, West Chester, Mt. Holly, Trenton, Pottstown, Gap and Glassboro. In the southwestern corner of the state the choices are Pittsburgh, Sarver, Washington, Waynesburg, Uniontown, Greensburg and Somerset.
For those in the northwest, the Lake Erie shoreline is divided into Lake Erie, Erie, Fairview, Albion and Meadville. A quick flick of the mouse can show how far inland the lake effect snow is likely to cover.
The Hometown Weather web page links to the Penn State/National Center for Atmospheric Research mesoscale weather model, which uses data from the National Weather Service to create simulated future weather data. The model generates temperature; relative humidity; wind speed and direction; precipitation, and barometric pressure for a 36-hour time span in three-hour intervals for each grid square. While a column for cloud cover exists, it is currently empty. The model is operating in real time and so can provide up-to-date forecast information.
"The record may start at 8:00 p.m. last night and go through 8:00 a.m. tomorrow morning," says Young. "By looking at the table of data, afternoon highs or evening lows are easy to read and expected levels of precipitation can remind one to bring along an umbrella."
The Hometown Weather page also provides the option for graphic information. This is especially helpful when a trend is more important than the individual numbers as with barometric pressure. If the graph shows the pressure dropping, chances are the weather will change and a storm is approaching. A rising pressure graph should suggest clear or improving weather.
"The best thing about this weather page is that the entire state loads on the screen in less time than it takes to load one National Weather Service map," says Young.
The rapid access of the weather data is possible because the Internet interface on the Web page, http://mm5.met.psu.edu/mm5/MM5data.html, is written in Java.
All the forecast data are sent when the page loads. For people accessing the Internet via a telephone modem, the page may load slowly, but once the page is up, clicking anywhere on the map immediately opens the weather data for that location. Unfortunately, the page can only be viewed with a Java-capable net browser, such as the latest version of Netscape or Explorer and cannot be viewed by those using Windows 3.1 or less.
"Only three or four groups around the country run this mesoscale weather model in real time," says Young. "Penn State is the only one providing an interface for real-time local weather."
The presentation of information on the Hometown Weather page is not yet set in stone. Currently the barometric pressure is in millibars of mercury and the wind direction is in degrees from north rather than the standard word directions. The wind speed is in knots per second.
"We are not sure exactly how people would like to see this information," says Young. "If we come up with a consensus, we will change the output."