Thurs 25 Aug 2011

First image is of the winds aloft at 850 mb (approx 5000 ft). Winds over the state were light with a westerly component.  Winds to the north, while not exactly pushing migrants south, have turned more favorable for migrants ready to move.

Incidentally, great image as hurricane Irene develops off the southeastern coast.  Remember these are the wind speeds at roughly 5000 ft not surface winds.

Second image is a snapshot of the base velocity showing north to south directionality at a peak of 15 to 20 knots.

Third image is an animated gif with snapshots every half hour of the base reflectivity above radar station RTX.  Animation runs from around 8:00 pm pdst yesterday evening through 5:00 am pdst this morning. (Click on the thumbnails to view the full-sized images and animation.)

Sunset last night was at 8:03 pm pdst.

Radar was in precipitation mode all night, so density comparisons are difficult to make.  There was movement into the area as seen on the velocity image — just not sure how dense it was.

I have put an image of the national radar composite at the bottom of this post.  Take a look at the winds aloft again and then compare the winds to the image below.

Note how the strong southerly flow along the east coast has shut down migration across the region.  But along the Mississippi and Central flyway, where there are strong northerly winds behind the storm front, the radar is lit up with some of the densest migration of the season.