Forecast and Analysis

Regional Migration Forecast: 19-26 September 2014

Andrew Farnsworth The Cornell Lab Sep 19, 2014

Continental Summary

Favorable conditions bring light to moderate movements for the West’s weekend and moderate to heavy movements for the East’s work week, with unsettled conditions bringing a halt to these movements in most areas to close the forecast period. Species on the move this week will include Greater White-fronted Goose, Northern Harrier, Northern Flicker, Eastern and Say’s Phoebes, Ruby-crowned Kinglet, Brown Creeper, Marsh and Winter Wrens, Swainson’s and Gray-cheeked Thrushes, Yellow-rumped and Palm Warbler, Savannah, Golden-crowned, White-crowned, White-throated, Swamp, Lincoln’s, and Fox Sparrows, and Rose-breasted Grosbeak.

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.


Favorable conditions bring light to moderate movements to many areas of the region to kick off the weekend, particularly from the Pacific Northwest through the northern and central Rockies. But by the beginning of the work week, conditions begin to change rather markedly to much less favorable, diminishing the extent and intensity of movements. These unfavorable conditions, which will include southerly flow and increasing precipitation in a number of locations, will present as isolated light to moderate movements that become increasingly sparse as the week continues. Species on the move this week will include Golden-crowned Sparrow, Greater White-fronted Goose, Fox Sparrow, Ruby-crowned Kinglet, White-crowned Sparrow, Varied Thrush, Dunlin, Yellow-rumped Warbler, Red-naped Sapsucker, Palm Warbler, Cackling Goose, Lincoln’s Sparrow, Hermit Thrush, and Say’s Phoebe.

Great Plains

As southerly flow dissipates, a frontal system passes and a wind shift to the north follows, moderate to heavy movements will ensue over the course of the week across the region. Some of these movements may be very heavy in the northern and central Plains. This pulse of migrants does not continue with such intensity beyond the beginning of the work week, as southerly flow returns and tempers movements. And by the middle of the week, southerly flow has taken a strong hold in most areas, which will keep movements scattered and light. Species on the move this week will include White-crowned Sparrow, Yellow-rumped Warbler, Dark-eyed Junco, Savannah Sparrow, Lincoln’s Sparrow, Ruby-crowned Kinglet, Harris’s Sparrow, Orange-crowned Warbler, White-throated Sparrow, Winter Wren, Spotted Towhee, Fox Sparrow, Northern Flicker, Swamp Sparrow, and Franklin’s Gull.

Upper Midwest and Northeast

Unfavorable conditions across the region to start the weekend begin to yield by Sunday as a new frontal boundary approaches. Moderate to heavy movements will occur following its passage through the Upper Midwest and Mississippi River valley on Sunday night and the remainder of the region by Monday and Tuesday nights. By the middle of the week, conditions become more marginal in most areas, which will see movements diminish in extent and intensity in most areas. However, some continued moderate movements are likely in the Appalachians and mountains of New England and coastal mid Atlantic states, albeit with decreasing likelihood as the week comes to a close. Species on the move this week will include Golden-crowned Kinglet, White-crowned Sparrow, Yellow-bellied Sapsucker, Ruby-crowned Kinglet, White-throated Sparrow, Yellow-rumped Warbler, Dark-eyed Junco, Swamp Sparrow, Winter Wren, Lincoln’s Sparrow, Brown Creeper, Rusty Blackbird, American Pipit, Fox Sparrow, and Blue-headed Vireo.

Gulf Coast and Southeast

After a weekend of marginal conditions that allow scattered moderate to locally heavy movements to occur, widespread favorable conditions arrive to begin the work week. With these changes will come widespread moderate to heavy flights on Monday and Tuesday nights. These movements will continue through the remainder of the week, but they will become increasingly sparse as more precipitation and unsettled conditions return as the frontal boundary stalls. However, winds are forecast to have significant easterly components in many areas, suggesting that larger movements are possible in precipitation free areas across the region. Additionally, birders should watch the distributions of migrants and precipitation on Wednesday and Thursday nights, as there is potential for fallouts and concentrations where these interact. Species on the move this week will include Rose-breasted Grosbeak, Peregrine Falcon, Palm Warbler, Swainson’s Thrush, Ruby-crowned Kinglet, Lincoln’s Sparrow, Gray-cheeked Thrush, Merlin, American Kestrel, Gray Catbird, Savannah Sparrow, Yellow-rumped Warbler, Northern Flicker, Northern Harrier, and Marsh Wren.