Generally unfavorable migration conditions prevail in the West this week, with those pulses of movements that occur featuring Green Heron, Least Sandpiper, Short-billed Dowitcher, Pacific-slope Flycatcher, Common Yellowthroat, and Clay-colored Sparrow, while the East sees a return to more summer like conditions until more favorable conditions and associated moderate flights of Common Nighthawk, Ruby-throated Hummingbird, Red-eyed Vireo, Blue-winged Warbler, Blackburnian Warbler, and Chipping Sparrow come after the middle of the week.
Wondering what was on the move this past week? Check out our regional migration analysis!
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 blue will experience conditions that are favorable for migration, and areas where blue and green (and red and blue) intersect and overlap may experience migrant concentrations and fallouts as migrants interact with precipitation.
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Marginal conditions remaining as a high pressure center arrives bring light to moderate flights on Friday night along the coast. But these flights are followed by a period of generally unfavorable and summer like conditions in most areas away from New England until the middle and end of the period. While New England sees a return to moderate and locally heavy flights on Sunday night, light movements prevail across the rest of the region. Wednesday and Thursday see a return of more favorable northerly flow in an increasing number of locations, spawning moderate to heavy flights from Wednesday through the end of the period. One interesting feature of note is what is now Erika – this storm may become a hurricane as it approaches the southeastern US and move into to this region as a dissociated tropical depression. BirdCast will monitor this system’s evolution and its potential to bring tropical waifs to the region.
Generally unsettled and unfavorable conditions prevail in the region during this forecast period, pending the passage of Erika in the middle of the week. Warm temperatures and southerly flow will keep flights light to locally moderate. Once Erika arrives and makes landfall, and its circulation begins to influence more significantly regional weather patterns, increasingly moderate to locally heavy flights are likely (this is typical during and after the arrival of such a system). By Wednesday and Thursday nights areas near and west of the Mississippi River valley will experience the best movements of the week.
Black Skimmer ** – Before July 1 6-Aug 4-Sep 18-Sep
Southerly flow and warmer temperatures overspreading the region will keep migration unseasonably quiet during this coming week. Light movements will be the norm, with locally moderate movements occurring when conditions allow. Not until Thursday does the hint of change appear, with favorable conditions in the Dakotas spawning moderate to heavy flights there.
Prothonotary Warbler * – – Before July 1 30-Aug 24-Sep
Cliff Swallow *** – – Before July 1 2-Sep 25-Sep
Short-billed Dowitcher * Before July 1 6-Jul 7-Aug 2-Sep 4-Oct
Tree Swallow ** – – Before July 1 4-Sep 8-Nov
Aside from marginally favorable conditions in intermountain and desert locales on Monday to Wednesday nights that carry locally moderate flights, much of the early part of the forecast period is dominated by unfavorable winds and warm temperatures. By Wednesday night, areas from the Pacific Northwest through the northern Rockies will experience more typically fall like conditions, and moderate flights are likely in these areas. By Thursday night, these conditions expand to cover much of the northern portion of the West, and moderate migration so too will be more widespread.