Question[s] #7 ----------- Our group is having trouble with a) determining wind direction on the 1000 hPa geo. ht. and 10 m wind speed plot and b) determining whether or not we use the Z1000 at the cyclone center for the second half of the table (our ship values). Specifically for part a), what are some pointers you can provide such that we're not making an assumption too broad that could cause us to sink? Thank you! Answer to #7 ------------ [a] You know what the geostrophic wind direction would be, given the 1000 hPa geo. ht. contours. You can make an assumption about the impact of friction, requiring the actual wind direction to be directed properly for sub-geostrophic flow. The directional difference between the geostrophic and actual wind should not be more than 30 degrees. You can look at the project hand-out to figure out the actual wind speed compared to the geostrophic wind speed. [b] The ship lat/lon (column #2) of the bottom-half of the table template is the lat/lon position of the ship, not the position of the 1000 hPa low pressure (storm) center. You have to consider the ship position relative to the 1000 hPa low center to determine a reasonable wind direction and, depending on the deepening or filling rate at the cyclone center, whether the pressure gradient has changed and accounting for this change with an adjusted wind speed estimate at the new ship position. The ship position at P2 will go into the row labeled '[P1]' on the bottom half of the table, using the 1000 hPa wind speed and direction information estimated using the P1 maps. You can change the ship position from its inital position (in the row labeled 'Initial') to the [P1] row assuming the maximum ship speed and zero or calm winds initially. From the [P1] row on downward, you'll always be using the 'old' weather map information to determine the 1000 hPa wind speed and direction to help (or hinder) propelling the ship at its 'new' position. Examining last year's case study might help visualize and confirm if you are making reasonable assumptions.