An odd week in the East will feature good conditions for trans-Gulf flights (and fallouts), some early period moderate to locally heavy flights in the Plains, and a more quiet than usual Northeast with numerous species on the move including Green Heron, Black-bellied Plover, Lesser Yellowlegs, Caspian Tern, Blue-headed Vireo, Prairie Warbler, Yellow-throated Warbler, Worm-eating Warbler, Savannah Sparrow, and Summer Tanager, while the West sees a quiet heart of the period bookended by light to moderate flights that will included Lesser Yellowlegs, Long-billed and Short-billed Dowitchers, Black Tern, Plumbeous Vireo, Wilson’s Warbler, Hermit Warbler, and Lark Bunting.
Wondering what’s on the move now? Check out our analysis from the past week.
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.
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A strangely cold beginning to the period, featuring unfavorable westerly and northwesterly flow coupled with cool temperatures, will make the scattered light movements of the weekend seem exciting by the middle of the work week. Given the date, some movements may reach moderate levels if winds are weaker than anticipated, as birds will be on the move to some extent almost every night that rain and strong winds are not present. Some isolated pockets of locally more favorable in the Great Lakes and mid Atlantic states may see even heavier movements. Not until Wednesday or Thursday, and then primarily to north and east of the Appalachians, will conditions improve sufficiently for moderate to locally heavy flights to become slightly more widespread.
Canadian Maritimes Sidebar – a dip into the negative for the North Atlantic Oscillation, signifying a pattern of easterly flow over the North Atlantic, will be of great interest to birders in Newfoundland and other areas of northeastern Canada. Such a pattern characterizes the arrival of European vagrants including European Golden-Plover and other goodies. Birders should keep a watchful eye in these areas, as should birders in New England.
Moderate to heavy flights, including some nice inputs of trans-Gulf migrants, are on tap for the weekend. Some of these flights may encounter precipitation, continuing potential for fallouts similar to those that the region has experienced in previous weeks. This potential looks especially good on Saturday, Monday, Tuesday, and Wednesday, from western Gulf areas through peninsular Florida, as a stronger and more organized disturbance passes through the region. However, with the passage of this system, migration is scarce to end the period, with generally unfavorable conditions for flights across the region and far south into the Gulf of Mexico.
Unsettled conditions, including some potential for strong storms, will bring a mixed bag of movements to the region to kick off the weekend. Areas away from storms and rain will experience moderate to heavy flights on Friday night and into Saturday. But thereafter conditions become increasingly unfavorable for much of the week for the region, with cooler temperatures and northerly and westerly flow keeping most migrants on the ground. If winds are weaker than forecast, more substantial flights are likely, potentially reaching moderate and locally heavy amounts. By Wednesday night, and continuing through the end of the period, the next blast of southerly flow arrives in the northern and central Plains, and with it will come a blast of moderate and heavy flights.
Scattered favorable conditions around the region bring moderate pulses of migrants to the Desert Southwest and light to moderate movements elsewhere in the region to start the period. But the days that follow, up to Tuesday, will be much more quiet, with only scattered light movements in the wake of passing low pressure. A new burst of light to moderate migrant activity returns to end the period, with Wednesday and Thursday nights bringing more widespread movements as favorable conditions return to more of the region.