Interpretation of Arthur Greens
by Trudy Battaly
1. The seasonal distribution for BWs at Hook is from
Sep 10 to Sep 27. For the daily average number of BWs for the last
5 years, see
Seasonal_Distribution or look over the brief background.
Arthur Green's animation substantiates this migration window for BWs:
The high pressure systems on Sep 1 to Sep 6 results in no or few BWs.
2. Sep 9: A low pressure system moves in from the south and dominates
the weather patterns through Sep 13. Numbers of BWs are still low.
3. Sep 14: A high from the NW dominates the area and the BW numbers
begin to rise. A cold front and a 2nd high push down from the north on
Sep 15 and 16 and there are more hawks.
4. Sep 17 & 18: A few more BWs fly past as the residual highs are moving
5. Sep 19: Another cold front is followed by a high and the BW numbers
peak at more than 2000 on both Sep 19 and Sep 20.
6. Sep 25 & 26: The next cold front and high result in the last double
digit figures for BW for the year, as the BW window closes.