1-50. Surface  lows  move  with approximately  what  percent  of  the thermal wind in the 1000- to 700-hPa  stratum? 1. 50% 2. 75% 3. 80% 4. 100% 1-51. Relative to the use of statistical studies  in  forecasting,  which  of the  following  statements  is accurate? 1. Valid  statistical  studies provide  the  forecaster  with virtually  infallible  rules  in making  long  range  forecasts 2. Statistical  studies  are  of little value to the forecaster in predicting the future behavior of storms, as they are mainly  for  climatological purposes 3. Valid  statistical  studies should  be  scrutinized  and weighed in light of other factors  in  the  integrated forecast 4. Once a weather situation has been  identified,  the  forecaster can assume the feature will behave  in  an  identical  manner 1-52. The  objective  technique  for  the prediction  of  maritime  cyclones  may be employed for which of the following  periods? 1. All  maritime  cyclones  in  all seasons of the year 2. All  maritime  cyclones  during the  winter  months  only 3. All  maritime  cyclones  during the  summer  months  only 4. Maritime  cyclones  whose  initial positions are north of 30° latitude  during  the  winter months 1-53. During  periods  of  westerly  flow aloft,    surface highs tend to migrate  in  what  general  manner? 1-54. When the direction of movement of a surface low is parallel to the warm sector  isobars,    it can be expected to deepen with a rate equal to which  of  the  following  location pressure  tendencies? 1. The  warm  sector  tendency 2. The tendency in advance of the warm front 3. The tendency at the trough line 4. The tendency north of the center of the low 1-55. Wave cyclones are most likely to develop along a front in what location? 1. Along  the  accelerating  portion of a cold front where the 700-hPa  winds  are  parallel  to the front 2. Along the decelerating portion of a cold front where the 700-hPa  winds  are  parallel  to the front 3. Along the decelerating portion of a cold front where the 700-hPa  winds  are  perpendicular to the front 4. Along  the  accelerating  portion of a cold front where the 700-hPa  winds  are  perpendicular to the front 1-56. A change in pressure at the surface can be estimated to be equal to which  of  the  following  conditions? 1. A change in pressure at some level aloft 2. A change in mass between the surface and some upper level 3. A change in pressure at some upper level plus the change in mass  between  the  surface  and that upper level 4. A change in pressure at some upper level minus the change in mass between the surface and that upper level 1. Toward the east 2. Poleward 3. Toward  areas  of  decreasing isallobaric  gradient 4. Equatorward 7