Pulses of light to moderate movements will follow the favorable conditions across the West, particularly early in the week, and will feature Lesser Yellowlegs, Dunlin, Bonaparte’s Gull, Caspian Tern, Vaux’s Swift, Black-throated Gray Warbler, Wilson’s Warbler, and Yellow-headed Blackbird, while the East sees moderate to heavy flights that track those favorable conditions early to mid week and that feature a large number of arrivals including Green Heron, Willet, Wilson’s Snipe, Red-eyed Vireo, Cliff Swallow, Yellow-throated Warbler, Kentucky Warbler, and Swamp Sparrow among many others.
Wondering what species are migrating through right now? Check out our analysis for the past 7 days.
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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The passage of a cold front cleans the slate on Friday and Saturday, setting the stage for a new round of favorable conditions to begin the work week. Moderate to locally heavy movements will be widespread on Monday and Tuesday ahead of an approaching low pressure system. Birders should watch the passage of this system carefully, as there is potential for concentrations and fallouts where it meets migrants, especially along the Atlantic Coast on Tuesday. A similar pattern follows for the end of the week, as the next low pressure center spins its way into and through the region.
The list of arrivals is diverse and large in the Southeast! And the forecast is similarly diverse, with several extensive disturbances bringing a mix of precipitation, favorable winds, and then clear skies and northerly winds. Birders should watch the progression of these disturbances carefully, as several may be timed properly to create fallouts along the entirety of the Gulf Coast. Monday and Tuesday look especially interesting because of the combined favorable wind forecast for Yucatan and northern Central America and the timing of the rain forecast along and over the Gulf of Mexico. By the end of the week, the disturbances break briefly, as the next round of favorable conditions builds into Texas. Moderate to heavy flights are likely this week where and when rain is not falling.
Three reasonably distinct periods of favorable conditions spread across the region of the forecast period, first on Saturday and Sunday, again on Tuesday and Wednesday, and finally to end the period on Friday. In each of these bouts of southerly flow and warmth will come moderate to heavy flights of migrants. Following each of these bouts, rather strong storms may be possible as frontal boundaries between air masses push through the region. These passing storm systems may bring concentrations of birds, depending on the timing of rain and birds as well as the strength of the storms. Regardless, each passing disturbance will ground migrants for a day or two and shut down nocturnal flights.
From Friday through Tuesday favorable conditions for migrants to fly extend to many parts of the West, and light to moderate movements will follow in many areas. Saturday and Monday looks especially favorable for flights, particularly in California and the Desert Southwest, but also in parts of the northern Rockies that have so far largely missed out on the fun. The second half of the forecast period will not be as favorable, with less extensive movements that generally occur in the typical hot zones in the southwest.