Thanks David, I misunderstood and thought you were talking about bird movment just after sunset previously.
Nevertheless, I don't recall seeing such an isolated area of broad-scale movement before. I can theorize how it might happen, I've just never noticed it. Bill ----- Original Message ----- From: David La Puma To: Bill Evans Cc: [email protected] Sent: Monday, May 02, 2011 4:45 PM Subject: Re: [nfc-l] odd NEXRAD pattern Bill That was my point. Clear air isn't an issue. I think the combined reflectivity and velocity suggest bird migration. You ask "what was going on" and my response to that was that the wind conditions were such that migration-ready birds did exactly what you'd expect in the absence of strong opposing winds and precipitation... they migrated. The winds elsewhere around KUEX were stronger and northerly. cheers D On Mon, May 2, 2011 at 4:28 PM, Bill Evans <[email protected]> wrote: Chris, David, Thanks for your responses -- but the fact that KUEX was in clear air mode doesn't solve the mystery for me. Many other midwestern NEXRAD stations were in clear air mode at 11PM last night. If the reflectivity shown was due to the clear air setting then one would expect other stations in the region operating in clear air mode would have shown similar activity. For me this appears like an unusually localized broad-scale region of biotargets in the atmosphere -- the NEXRAD stations at North Platte and Valley, NE appear to be on the periphery, showing less, of whatever activity this was. Bill E ----- Original Message ----- From: David La Puma To: Bill Evans Cc: [email protected] Sent: Monday, May 02, 2011 3:25 PM Subject: Re: [nfc-l] odd NEXRAD pattern After reviewing the archive it looks like the KUEX radar was set on clear-air mode (here's the inventory color coded by mode: http://www.ncdc.noaa.gov/nexradinv/displaygraphs.jsp?yyyy=2011&mm=05&dd=01&id=KUEX&product=AAL2) but I don't think that explains the burst of activity after sunset. Based on the velocity (20+ kts) and the direction of travel (SE->NW), those are most likely birds. I can't pull an archived radiosonde map for the area at 8pm last night, but I suspect (based on the more current radiosonde data) that the winds between the surface and ~2-3k feet were light enough to allow migration to occur... so I think this is just a case of locally good migration conditions during the period when the highest densities of migrants are likely to fly. If the meteorologists want to chime in with some archived wind data, that would be cool too! Also, Jeff Buler at U Delaware (also doing some really cool radar ornithology work) pointed me to this very cool website: http://soar.ou.edu/ where you can view the unfiltered NEXRAD data back to 2008 (they are working backwards from 2011 to fill in the missing years). Just make sure you're viewing the non-QC'd mosaic to include biological targets. Cheers David On Mon, May 2, 2011 at 1:17 PM, Bill Evans <[email protected]> wrote: Interesting NEXRAD image from last: substantial migration to the east of a front in the eastern US, nothing unusual about that, but strange is one isolated radar lighting up in south-central Nebraska. -Bill E http://www.rap.ucar.edu/weather/radar/displayRad.php?icao=KUSA&prod=bref1&bkgr=black&endDate=20110502&endTime=4&duration=0 -- NFC-L List Info: Welcome and Basics Rules and Information Subscribe, Configuration and Leave Archives: 1) The Mail Archive 2) Surfbirds 3) BirdingOnThe.Net ------------------------------------------------------------------------ Please submit your observations to eBird! -- -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.NortheastBirding.com/NFC-L_SubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/[email protected]/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NFC-L 3) http://birdingonthe.net/mailinglists/NFCL.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
