Interpretation of Arthur Green’s Weather Animation        
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 out.

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.