Forecast and Analysis

Regional Migration Forecast: 26 September – 3 October 2014

Andrew Farnsworth The Cornell Lab Sep 26, 2014

Continental Summary

Favorable conditions at the end of the forecast period bring widespread light to moderate movements to the West and moderate to heavy movements to the Plains, while increasingly scattered moderate movements occur in the East in more summer-like conditions. Species on the move this week will include Cackling, Snow, and Great White-fronted Geese, American Wigeon, Ring-necked Duck, Yellow-bellied Sapsucker, Northern Flicker, Hermit and Varied Thrushes, Ruby-crowned and Golden-crowned Kinglets, Brown Creeper, Gray Catbird, Orange-crowned, Palm, Yellow-rumped Warblers, Savannah, LeConte’s, Fox, White-throated, White-crowned, Golden-crowned, Harris’s, and Lincoln’s Sparrows, and Dark-eyed Junco.

Arrows show wind speed and direction (arrow points in the direction to which wind is blowing) 100 m above ground level. Areas with southerly winds are colored red; northerly winds colored blue. Accumulated precipitation (in 6 hour intervals) is green, outlined by white. Broadly speaking, areas of the map in red will experience conditions that are favorable for migration, and areas where red and green (and red and blue) intersect and overlap may experience migrant concentrations and fallouts as migrants interact with precipitation.


Light to moderate movements will begin the weekend in portions of the Pacific Northwest and the Great Basin into the northern Rockies as the remainder of the region remains under unfavorable conditions. By Monday night a disturbance has become more organized and moves out of the Rockies, allowing for more favorable conditions and light to moderate movements to spread farther south in the region. As this system continues its move east, much of the region sees favorable conditions and light to moderate movements should reach their greatest extents of the period by Wednesday and Thursday nights. Species on the move this week will include Cackling Goose, Palm Warbler, Varied Thrush, Greater White-fronted Goose, Golden-crowned Sparrow, Ruby-crowned Kinglet, Dunlin, Yellow-rumped Warbler, Snow Goose, Ring-necked Duck, American Wigeon, Fox Sparrow, Hermit Thrush, White-throated Sparrow, and American Pipit.

Great Plains

With the exception of moderate to locally heavy movements in the northern Plains over the weekend, most of the region will experience unfavorable conditions and limited movement until a frontal boundary pushes through the region on Wednesday night. Once this system pushes through, moderate to heavy movements will be widespread across the region, presumably throughout the end of the forecast period. Species on the move this week will include White-throated Sparrow, Dark-eyed Junco, Harris’s Sparrow, Le Conte’s Sparrow, Yellow-rumped Warbler, White-crowned Sparrow, Lincoln’s Sparrow, Fox Sparrow, Song Sparrow, Long-billed Dowitcher, Swamp Sparrow, Eastern Meadowlark, Brown Creeper, Cackling Goose, Ruby-crowned Kinglet.

Upper Midwest and Northeast

Widespread moderate to heavy movements kickoff the weekend, but the extent and intensity of these movements quickly decreases as more marginal conditions build into the region for the days that follow. Through the early part of the work week, more scattered moderate movements are likely as warm temperatures and southerly winds take hold. Increasing threat of precipitation also arrives with these warmer conditions, shutting down movements where it occurs, particularly east of the Mississippi River and Appalachians. By the end of the week, a frontal boundary moving into the region spawns moderate to heavy movements in its wake for the Upper Midwest and Mississippi River valley. Species on the move this week will include Golden-crowned Kinglet, White-crowned Sparrow, Dark-eyed Junco, Hermit Thrush, White-throated Sparrow, Yellow-rumped Warbler, Swamp Sparrow, Ruby-crowned Kinglet, Fox Sparrow, Pine Siskin, Ruddy Duck, Brown Creeper, Winter Wren, Yellow-bellied Sapsucker, and Brant.

Gulf Coast and Southeast

Moderate to heavy movements spread from the Mississippi River to the Carolinas as calm and northerly winds facilitate migrant exodus to kick off the weekend. However, unsettled is the word thereafter through the remainder of the period, as movements, mostly moderate to locally heavy, will become increasingly scattered as unfavorable winds and precipitation take hold. These movements will be apparent in the Mississippi River valley to begin the week, gradually shifting to the southern Appalachians and eventually the coastal plain by mid week. Species on the move this week will include Yellow-bellied Sapsucker, Ruby-crowned Kinglet, Lincoln’s Sparrow, Yellow-rumped Warbler, House Wren, Orange-crowned Warbler, Swamp Sparrow, Northern Flicker, Palm Warbler, Gray Catbird, Indigo Bunting, Savannah Sparrow, White-throated Sparrow, American Kestrel, and Northern Harrier.