Forecast and Analysis

Regional Migration Forecast: 22-29 August 2014

Andrew Farnsworth The Cornell Lab Aug 22, 2014

Continental Summary

Light to moderate movements, primarily in the Pacific Northwest, highlight the period in the West, while the first organized frontal boundary does not bring compelling and more regional scale movements in the East until the end of the week. Species on the move this week Northern Pintail, Green-winged Teal, Blue-winged Teal, Osprey, American Golden-Plover, Semipalmated Plover, Buff-breasted Sandpiper, Red-necked Phalarope, Common Nighthawk, Least Flycatcher, Acadian Flycatcher, Pacific-slope Flycatcher, and numerous warblers.

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 will bring light to moderate movements to the Pacific Northwest to kick off the weekend, but the remainder of the region sees only gradual improvements in conditions for movements of such intensity in northern areas. Much of the southern portion of the West experiences unfavorable conditions and forecasts including precipitation. By early to mid week conditions improve in many areas for these movements to become more widespread, if patchy through the remainder of the period. Note that precipitation forecast for portions of the northern and eastern Rockies over the weekend and into the early week could bring concentrations and localized fallouts where migrants are moving, so birders should be keep an eye on favored hotspots and stopover habitats in these areas. Species on the move this week will include Northern Pintail, Red-necked Phalarope, Green-winged Teal, Townsend’s Warbler, Orange-crowned Warbler, Northern Shoveler, Pectoral Sandpiper, American Wigeon, Semipalmated Plover, Wilson’s Warbler, and Pacific-slope Flycatcher.

Great Plains

Aside from moderate to some isolated heavy movements in the northern Plains, much of the region begins the weekend and early part of the week with unfavorable winds and temperatures and forecast precipitation. However, Tuesday and Wednesday nights see the passage of a frontal boundary, bringing more widespread moderate and locally heavy movements for the region. After this system passes, conditions become less favorable, with a return to more southerly flow and warmer temperatures to end the forecast period dampening most movements to light to moderate intensities. Species on the move this week will include Wilson’s Warbler, Chestnut-sided Warbler, Magnolia Warbler, Northern Waterthrush, Osprey, Mourning Warbler, Black-and-white Warbler, Tennessee Warbler, Least Flycatcher, American Redstart, and Warbling Vireo.

Upper Midwest and Northeast

Most of the forecast period sees the region without a compelling and widespread movement, as scatter precipitation and unfavorable winds will keep most migration intensities light to locally moderate. Aside from some isolated heavier movements in conditions that may be slightly more favorable than forecast, particularly in portions of New England and the Ohio River valley, the first improvements facilitating more widespread movements do not arrive until the end of the week. And these conditions come only to a small portion of  region, in the western Great Lakes and Mississippi River valley, where moderate to locally heavy movements end the period. Species on the move this week will include Magnolia Warbler, Blackpoll Warbler, Wilson’s Warbler, Black-throated Green Warbler, Tennessee Warbler, Black-throated Blue Warbler, Bay-breasted Warbler, Buff-breasted Sandpiper, Common Nighthawk, American Golden-Plover, Nashville Warbler, Northern Parula, American Redstart, and Chestnut-sided Warbler.

Gulf Coast and Southeast

Southerly flow and scattered precipitation dominate the period, keeping most movements light to locally moderate. However, a few areas of more favorable conditions will occur locally in the region, particularly to end the weekend to the east of the Mississippi River, where more moderate movements will occur. Birders in the southern Appalachians in particular should watch for concentrations to end the weekend and begin the week, particularly in mountain stopover habitats and migrant traps, as migrants may interact with scattered precipitation in these areas. Species on the move this week will include Baltimore Oriole, Wilson’s Warbler, Mourning Warbler, Northern Waterthrush, Chestnut-sided Warbler, Canada Warbler, Blue-winged Teal, Ovenbird, Magnolia Warbler, Acadian Flycatcher, Eastern Wood-Pewee, Tennessee Warbler, Bank Swallow, and Black-and-white Warbler.