Forecast and Analysis

Regional Migration Forecast: 11-18 October 2013

Benjamin Van Doren The Cornell Lab Oct 11, 2013

Continental Summary:

Widespread light and moderate movements across the West are still apparent, as a major pulse of northerly flow brings a large flight to the East by midweek. Birds on the move this week will include Northern Harrier, Chimney and Vaux’s Swifts, Orange-crowned Warbler, Eastern and Western Meadowlarks, Song, White-crowned, and White-throated Sparrows, and Dark-eyed Junco.

Again, this week’s 925 millibar forecast imagery looks distinctly different from previous weeks’ animations. This is because our collaborators that assist in producing the baseline 925 millibar forecast wind and precipitation maps were affected by the shutdown of the U.S. government. Precipitation is included in this week’s animation, as the green-to-red colors (blue is wind speed); the key on the left is 6-hr precipitation in inches.



Light to moderate movements prevail West of the Rockies to begin the period, spreading East of the Rockies and intensifying to more moderate movements by Monday night. This pattern continues through the forecast period, as conditions for movements East of the Rockies improve further for more extensive and intensive movements. Additionally, raptor movements and other diurnal species’ movements will be apparent in many areas this week, though most intense in the northerly and northwesterly flow to the East of the Rockies. Birds on the move this week will include Bufflehead, Red-tailed Hawk, Vaux’s Swift, Western Wood-Pewee, Barn and Violet-green Swallows, Orange-crowned, Yellow, and Wilson’s Warblers, and Western Tanager.

Great Plains

A low to the North of the Canadian Prairies brings a pulse of moderate to locally heavy movement to the Plains for Saturday night, followed by a much more intense pulse on Tuesday through the remainder of the period. This latter pulse will see moderate movements with locally heavy and very heavy movements across the region. This movement will also include conditions favorable for diurnal migration, so skywatchers should prepare accordingly. Birds on the move this week will include numerous waterfowl including Gadwall and Redhead, Northern Harrier, Sandhill Crane, Northern Shrike, Horned Lark, Western Meadowlark, American Tree and White-crowned Sparrows, and Dark-eyed Junco.

Upper Midwest and Northeast

Moderate to heavy coastal movements begin the period East of the Appalachians, diminishing in extent to northern New England by Saturday and Sunday nights. As low pressure to the North of the region moves East, the Great Lakes and Mississippi and Ohio River valleys light up with moderate to locally heavy movements by Sunday night. A similar pattern occurs on Monday and Tuesday night, with East of the Appalachian movements dominating the radar and diminishing in extent to northern New England. A strong front bisects the region by mid to late week, spawning moderate to heavy movements West of the Appalachians but gradually shutting down movements East of the Appalachians. Birds on the move this week will include Chimney Swift, Eastern Phoebe, Gray Catbird, Nashville, Magnolia, Black-throated Green, Black-throated Blue Warblers, Common Yellowthroat, American Tree Sparrow, and Dark-eyed Junco.

Gulf Coast and Southeast

Moderate to heavy movements are the norm to begin the forecast period in the Southeast East of the Mississippi River. These continue and become increasingly more easterly in extent through Tuesday night, whereas most of the region West of the Mississippi experiences much less favorable conditions and primarily local light to moderate movements. This pattern changes by Wednesday night, as a strong frontal boundary pushes across the region and spawns moderate to heavy flights, some of which may be very heavy, to the West of the Mississippi. To end the period, widespread moderate movements occur, with some locally heavy and very heavy movements continuing primarily West of the Mississippi River. Birds on the move this week will include Chimney Swift, Yellow-bellied Sapsucker, Red-eyed Vireo, Hermit Thrush, Golden-crowned and Ruby-crowned Kinglets, American Redstart, Orange-crowned and Yellow-rumped Warblers, Eastern Meadowlark, Savannah, Song, Swamp, White-throated and White-crowned Sparrows.