Wed 28 Sept 2011

If you can, today is a great day to go birding!  The cold front has been replaced with a high pressure system, the winds, although not strong, are from the north, and those bottled up migrants are taking to the sky.  At 3:30 AM this morning i went out to listen to the activity and it was ACTIVE!  Passerine flight calls, geese, ducks and a few night hawks, all up in the sky over my SE Portland home.

First image is of the winds aloft at 850 mb (approx 5000 ft). Winds are in the migrant’s favor today!

Second image is of the surface winds and pressure. Here you can see where the high pressure system has replaced the cold front we have been working through since the 23rd. (should be some nice autumn weather for a while too)

Third image is a snapshot of the base velocity showing north to south directionality at a peak of 20 to 25 knots.

Fourth image is the animated gif with snapshots every half hour of the base reflectivity above radar station RTX.  Fortunately the radar switched over to Clear-air mode right at sunset!  There was a major flight last night with some of the highest density readings of the season, reaching up into the 20-25 bBZ range.  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.)

Since the gif loop moves pretty fast i have put a static image of the reflectivity readout below showing the extent and density of the readings last night.

Sunset last night was at 6:59 pm pdst.