Winds Aloft Charts #3 and #4

Source: Air Ministry, Daily Weather Report of the Meteorological Office, London, Upper Air Section, Wednesday, 4th August 1943 at about 06 Greenwich Mean Time (ed. UTC, or Zulu).
No. 8833.

Left panel caption is: The continuous lines are contour lines of the 300 mb (millibar) surface. The dotted lines are isopleths of the thickness of the layer 500-300 (sic) mb.

Right panel caption is: Contour lines of Height of Tropopause. Meteorological Office, Air Ministry, Kingsway, London, W.C.2
Nelson K. Johnson, K.C.B., D. Sc., Director

Editorial Comment: These charts depicit upper air wind velocities at specific heights ("pressure altitudes") in the atmosphere at the time noted (approximately 6AM local time) on the morning of the 4th of August, 1943. These "winds aloft" charts are critical to proper flight planning. From these, and other charts, a new "flight plan" will be constructed (the "re-navigation" project). The new plan (which will account for known and forecasted upper wind velocities (speed and direciton)) will be compared against the course the crew of 801 is known to have actually flown (from letters from both the Pilot and Navigator).

Deviation from the "new plan" may reveal that the crew was misinformed or incorrectly informed. It also, however, may show that the weather data was invalid at the time of the flight (this is the positon the navigator took). Finally, the re-navigation may show something altogether different and unexpected.

(I must purchase new World Aeronautical Charts ("WAC") charts for this exercise to be completed.)