Welcome to DataStreme Atmosphere. We hope the use of current weather information will become an engaging and anticipated daily experience. We encourage your exploration of the DataStreme Atmosphere weather products from the websi= te and the use of that material in your classroom or school.
After completing the introductory portion of Investigation 1A in the = Investigations Manual, use the WeatherCycler provided in the Study Guide to answer the following questions.
1= . Go to the WeatherCycler. The view in= the large window on the face of the device depicts a surface weather map. The t= hin curved lines appearing on the map are isobars. With the slide pushed all the way into the WeatherCycler, the i= sobar pattern displays a [(high) (low)] pressu= re system. The slide, when pulled out about half-way, shows the isobar pattern around a [(high) (low)] pressure system.=
2= . If the innermost closed isobar surrounding the center of high pressure represe= nts 1020 mb and the isobars are drawn with the conventional interval, the innermost closed isobar surrounding the center of low pressure must have a value of ______ mb.
3= . Imagine yourself at the weather station represented by the circle directly above the green pointer (B) when the slide is pushed all the way into the device. If = the map's pressure field is that described in (2) above, the air pressure at the station is near [(1008) (1012) (1016)] mb.
Image 1 ("Pressures" map) was acquired from the course website and reports surface air pressures (corrected to sea level) rounded to the neare= st whole millibar at 00Z 30 AUG 2009, actually 8 P= M EDT (7 PM CDT, 6 PM MDT, 5 PM PDT, etc.) on Sunday evening.
4=
. The
lowest plotted air pressure on the map is [(1003)(1006)(1009)] mb at several stations in
5=
. The
highest reported pressure is 1023 mb in [(
6= . The isobars in the conventional series that will be needed to complete the pres= sure analysis between the lowest and highest values on this map are: [(= 1006, 1010, 1014, 1018)(1007, 1011, 1015= , 1019)(1008, 1012, 1016, 1020)].
An isobar is not needed when a pressure value the same as that of the is=
obar
occurs at a single point and there are no pressures less/greater than its v=
alue
reported nearby. More than one isobar of the same value may need to be draw=
n if
pressure values located in separate sections of the map area require it. Two
isobars have already been drawn in southern
Using a pencil, follow the steps below to complete the pressure analysis to determine the pressure pattern that existed at the time the observations were made. Consider each pressure value to be located at the center of the reported number.
7=
. Arbitrarily
we might start by drawing the 1008-mb isobar, the first of the series. This
isobar may be started by going through the "1008" located in nort=
hern
Continue drawing and labeling isobars of the series where they existed
within the data pattern. Note that several of the isobar values appear in b=
oth
the northeastern
8=
. Image
2 is the analyzed surface pressure map from the National Oceanic and
Atmospheric Administration's (NOAA)
Compare your isobar pattern with that drawn o=
n the
Image 2 map. The Image 2 map is constructed by computer based on a much more
complete set of pressure values. (This may account for some of the variatio=
ns
between your analysis and that by the computers. It also is the source of
several of the plotted Hs and Ls denoting locally minimally higher or lower
pressure centers, respectively.) The L located in the Atlantic Ocean off
9=
. The
bold red and blue lines are fronts that are generally associated with the L=
ows
(L). Dashed orange lines are troughs or extensions of lower pressure often
acting like fronts. Light blue, green and yellow shadings scattered across =
the
map are areas where radar beams were reflected back to the radar sites
indicating varying intensities of precipitation (see scale to the left marg=
in).
Generally, the radar-indicated precipitation areas [(are
By analyzing the pressure values reported on weather maps to find pressu= re patterns, one can locate the centers of locally highest and lowest pressure= s, respectively. We will see that these pressure centers often mark the midpoi= nts of major weathermakers.
The DataStreme Atmosphere website routinely delivers unanalyzed ("Pressures") and analyzed ("Isobars &am= p; Pressures") surface pressure maps. Practice drawing isobars by calling= up the unanalyzed version. Use the DataStreme Atmo= sphere analyzed map as your "answer key". If appropriate, try having your students make a pressure analysis. You might share with your teacher collea= gues this "detective scheme" of analyzing surface air pressures to find storms or broad-scale air masses that are mentioned in the news.
Note: If you or your students would like to practice more on drawing isopleths (lines of a constant value) in groups of numbers, from simple to = more complex patterns, go to: http://profhorn.aos.wisc.edu/wxwise/AckermanKnox/chap1/Contour_page= 1.html.
Common NWS terminology for regions of the country which may be useful is= at: http:/= /www.hpc.ncep.noaa.gov/images/us_bndrys1_print.gif and ht= tp://www.hpc.ncep.noaa.gov/images/us_bndrys2_print.gif.
Place the answers to Current Weather Studies activities 1A and 1B on the= CWS Answer Form. If possible, take these investigations to your first course gr= oup meeting.
Return to <=
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