Forecast and Analysis

Regional Migration Forecast: 14-20 September 2013

Andrew Farnsworth The Cornell Lab Sep 13, 2013

Continental Summary:

Major movements begin the period in the East and West, followed by periods of less favorable conditions until another pulse of movements end the forecast period. Birds on the move this week will include Broad-winged and Sharp-shinned Hawk, Ruby-crowned Kinglet, Palm and Yellow-rumped Warblers, White-throated and White-crowned Sparrows.


Light to moderate movements will continue this week throughout many areas of the West. Areas West of the Rockies will experience a nice pulse of birds this weekend, in calm winds and generally clear skies. By the beginning of the work week, movements diminish in the presence of increasing precipitation. However, by Tuesday many areas are precipitation free, particularly in the Rockies and just East of the Rockies, allowing more extensive light to moderate movements occur in these locations. This pattern continues through the period, although continued scattered precipitation will keep birds grounded where and when it falls. Diurnal skywatchers should consider planning to watch overhead on Wednesday, Thursday and Friday in many areas from the Central Valley East to the eastern front of the Rockies, as conditions for diurnal movements will be favorable on those days. Birds on the move this week will include Ruby-crowned Kinglet, Yellow-rumped Warbler, and Fox, Golden-crowned, and White-crowned Sparrows.

Great Plains

Sandwiched between two strong high pressure centers, and then feeling the lingering effects of both of them departing, the region will experience mostly unfavorable and marginal migration conditions beginning this weekend and continuing through nearly the end of the forecast period. Light to moderate movements will be the norm during the period, with locally heavier movements occurring in the northern Plains on Sunday and Tuesday nights. Not until Thursday night does a strong low pressure center move across the region into the Great Lakes and spawn highly favorable migration conditions. Thursday and Friday nights will see widespread moderate to heavy movements, including some locally very heavy movements. On Friday, diurnal movements will be apparent in numerous areas, as well, so skywatchers should prepare accordingly to visit your favorite vistas. Birds on the move this week will include Broad-winged Hawk, Ruby-crowned Kinglet, Orange-crowned and Yellow-rumped Warblers, Harris’s, White-crowned, White-throated, and Lincoln’s Sparrows, and Dark-eyed Junco.

Upper Midwest and Northeast

Moderate to heavy movements, some of which will be locally very heavy, will occur across much of the region West of New England on Friday night, shifting farther East on Saturday night into most areas East of the Appalachians. Strong morning flights are possible in coastal areas on Saturday and Sunday mornings, so birders should plan to spend several hours each morning watching birds reorient and continue after their nocturnal movements. Saturday will be a good day to visit hawk watches and locations with good views of the sky. Another pulse of moderate to heavy movements begins in the western Great Lakes on Sunday night and expands East to many areas East of the Ohio River valley on Monday night. Tuesday will be another day for morning flight observation in coastal New Jersey, New York, and New England. By Tuesday night, however, only far eastern New England may see movements, as high pressure sitting off the mid-Atlantic brings southerly flow and warmer temperatures across much of the region. This pattern continues to the end of the forecast period, when the next major frontal boundary is forecast to bring moderate to heavy flights to the Mississippi River valley and portions of the Great Lakes. Birds on the move this week will include Broad-winged and Sharp-shinned Hawks, Yellow-bellied Sapsucker, Northern Flicker, Golden-crowned and Ruby-crowned Kinglets, Yellow-rumped and Palm Warblers, and White-throated and Lincoln’s Sparrows.

Gulf Coast and Southeast

Moderate to very heavy movements will begin the weekend across much of the region, continuing in eastern locations through Saturday night before diminishing on Sunday night to mostly light to moderate levels. Conditions become marginal and unfavorable for the beginning of the work week in most areas, and light to moderate movements will be the norm, with isolated heavier movements where winds are calm. This pattern will continue through the forecast period, although a strong frontal passage on Friday will bring favorable conditions for moderate to very heavy movements to some of the region West of the Mississippi and away from the coast. Birds on the move this week will include Sharp-shinned Hawk, Merlin and American Kestrel, Swainson’s Thrush, Black-throated Blue and Palm Warblers, Common Yellowthroat, and Rose-breasted Grosbeak.