MET 101 - Warm and Cold Fronts

Warm and Cold Fronts

You can find a printable PDF copy of the Warm and Cold Fronts handout, that was reviewed as a part of the prelab notes on the day we did this lab by Clicking Here. This handout contains information about the various weather factors that one would experience as a specific front was approaching your location and how that weather factor would change after the front passed by.

During the winter, low pressure systems (with their associated warm and cold front) that travel up the east coast are often called Nor'easters. The path the low pressure system travels off of the coast of Long Island greatly impacts whether or not the tri-state area will get rain or snow or a mixture of rain/sleet/snow. The ideal location for a low pressure system to travel across (south of Long Island) to produce copious amounts of snow is often referred to as the 40/70 Benchmark. That is a geographical point of 40° North latitude and 70° West longitude. If the low pressure system travels south of this benchmark then generally only eastern Long Island could see snow, if the the low pressure system travels north of this benchmark then the area generally gets more liquid/mixed precipiation.

For additional practice in drawing isobars, finding and labeling areas of high and low pressure and drawing in weather fronts CLICK HERE. This map contains surface station models which contain 7 of the weather variables (Temp, Dew Point, Present Weather, Wind Speed, Wind Direction, Pressure, and Sky Coverage) we talked about in the Surface Station Model lab.

You can perform one analysis, with new data, each hour. To see how your isobars, fronts, and locations of any high or low pressure systems should have been drawn CLICK HERE. Make sure this map has the same date and time (Z time found in the upper left hand corner) as the map you have analyzed, as the pressures may have changed or the weather systems may have moved. Keep in mind that your map will not look the same as the computer's as the computer may make some errors in its interpretation.

Note 1: Do not worry about finding fronts in or west of the Rocky Mountains as the various mountain ranges make it difficult to locate the fronts. Only find and draw fronts starting from the eastern half of the states of Montana, Wyoming, Colorado and New Mexico and areas extending east to the Atlantic Ocean.

Note 2: The computers map goes a little overboard when it locates the high and low pressure systems. There are NOT as many highs and lows on the map as the computers map may indicate. It is very rare for there to be either two high pressure systems or two low pressure systems within 200 miles of each other. Usually these are the same system. In general across the United States you will see a high pressure system, followed by a low pressure system (with its fronts), followed by a different high pressure system and then followed by another low pressure system (with its fronts), etc.... In other words one different individual system follows the other different system across the United States. To see a general map of where the pressure systems and fronts are most likely found you can take a look at the surface map provided by the Weather Channel. You should use the Weather Channel's map only as a reference as the time on your hand drawn map is most likely different than the time on the Weather Channel's map.

Note 3: The computers map in addition to the highs/lows and fronts also contains radar information, and trough lines (dashed red lines, which we have not discussed). Both of these pieces of information serve as an addional sources of information to a user.