NAME: __________________________________
Be sure to use the web tool for this case:
http://wx.gmu.edu/pix/case1.html
1) Give the longitude and latitude of the center of the 500mb closed low every six hours. Start at time=1, then time=5, and so on, up to time=37. The initial position of the closed low at time=1 is about 115W 38N. Plot maps at 500mb using an Expression of "z", and change the time value to see each map. Setting the CINT1 value to a value such as 30 or 20 willmake it easier to find the center of the low.
Make a table of times with both the lon and lat for the 500mb low center and for the surface low center (as described in step 2).
2) Give the longitude and latitude of the lowest Sea Level Pressure found near the 500mb upper closed low, at the same times as above. Use an Expression of "slp/100". The surface low will be close to the location of the upper low for most of the time. Setting the CINT1 value to 2 may make it easier to find the center of the low. Note: if you set and leave the CINT1 value from step 1, eg 20 or 30, you won't get many contour lines plotting slp! Maybe none!
3) Plot a vertical cross section at time=23 (18Z April 24) at longitude 90W. In the longitude Range fields, enter -90 in the first field, and blank out the 2nd field. For latitude, leave the values at their default (20 and 55). For the Level Range, enter 1000 in the first field, and 100 in the 2nd. In the Time Range fields, enter 23 in the first field, and blank out the 2nd field (if necessary). For the expression, use "mag(u,v)" to get the wind speed. Set the CINT1 field to blank to get the default contour interval. Give the pressure level and the latitude of the wind maximum.
4) Plot a time height cross section at longitude 90W and latitude 33N. In the longitude Range fields, enter -90 in the first field, and blank out the 2nd field. For Latitude Range, enter 33 in the first field, and blank out the 2nd field. For the Level Range, enter 1000 in the first field, and 100 in the 2nd. In the Time Range fields, enter 1 in the first field, and 40 in the 2nd field. For the expression, use "rh". Note: this may take a while to appear after you hit the submit button. List the times of maximum rh, where the rh is near 100% from the surface to the tropopause (about 200mb).
Bonus: Plot the pressure level of the tropopause (this is one of the model variables) at time=21. Describe what you see.