1-24. When changes in intensity of troughs and ridges aloft are forecast,    the time differential chart is most valuable in forecasting  which  of  the  following features? 1. Surface  pressure  centers 2. Single  height  change  centers with  no  apparent  history 3. Height change centers due to convergence  or  divergence  not associated with a short wave trough or ridge 4. Height change centers with a well-defined  history  that  are associated  with  short  wave troughs and ridges 1-25. You are trying to determine the change in intensity of a long wave trough and you notice that the warm air advection on the east side of the trough is   less than the cold air advection on the west side. What intensity change, if any, should you forecast for this trough? 1. It  will  fill  snowy 2. It will deepen 3. It will fill rapidly 4. None 1-26. Which  of  the  following  conditions is favorable for the filling of a trough? 1. The strongest winds are on the west side of the trough 2. The strongest winds are on the east side of the trough 3. The strongest winds are at the crest of the associated ridge 4. The strongest winds are in the southern quadrant of the trough 1-27. Upper  height  falls  are  associated with  low-speed  winds  approaching straight  or  cyclonically  curved contours. 1. True 2. False 1-28. What  seasonal  movement  and intensity changes occur with the semipermanent   high-pressure centers? 1. A  poleward  movement  and decrease in intensity in the summer 2. An  equatorward  movement  and decrease in intensity in the summer 3. A poleward movement and increase in intensity in the summer 4. An  equatorward  movement  and increase in intensity in the summer 1-29. A blocking high at 500-hPa has several closed contours, and the strongest winds in these contours are to the south in the easterlies. What forecast should you make for this  high? 1. It will move slowly eastward 2. It will move slowly westward 3. It will move rapidly eastward 4. It  will  remain  stationary 1-30. Intensification  of  a  blocking  high will occur under which of the following  conditions? 1. During high zonal index conditions 2. When cold air advection and mass  convergence  occur  in  the lower  troposphere 3. When  warm  air  advection  and mass divergence occur in the upper  troposphere 4. When cold air advection and mass convergence occur in the upper  troposphere 1-31. Concerning  the  extrapolation  of closed  lows,    which of the following statements is NOT accurate? 1. Extrapolation  should  only  be used for their movement 2. A central height trend over time  should  be  established 3. Changes in intensity may be determined 4. Extrapolation should be used in conjunction  with  other  methods 4