Wed 07 Sept 2011

First image is of the winds aloft at 850 mb (approx 5000 ft). Winds over the state were light and variable.  There were some localized 20 knot easterlies on the east side but shouldn’t prove to be a migration barrier.  The strong 30 to 40 knot ESE winds up north are more problematic for the pacific flyway.  They will move birds inland and stage them for the central flyways.

Second image is a snapshot of the base velocity showing north to south directionality at a peak of 20 to 30 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 7:41 pm pdst.

Density was not quite as heavy as last night. We didn’t have any reflectivity readings reach the 20 dBz range.  Still, plenty of new birds should be in the area today.  The heaviest concentrations are still east of Portland along the Cascades.

Dave over at woodcreeper.com has a great write-up on the east coast  migration.  The snapshot of the national composite below shows exactly what he is talking about.  The central flyways were active last night but not nearly as much as the previous two.  Probably a lot of the heavy flow over the last two nights was from “bottled  up” birds.  Much like the exodus in Maine tonight.

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