Editing Hail (section)

=== Factors favoring hail ===
Hail is most common within continental interiors of the mid-latitudes, as hail formation is considerably more likely when the freezing level is below the altitude of {{cvt|11000|ft|m}}.<ref name="mesoanal">{{cite web|url=http://www.meted.ucar.edu/resource/soo/MesoAnalyst.htm|title=Meso-Analyst Severe Weather Guide|first=Pete|last=Wolf|date=2003-01-16|access-date=2009-07-16|publisher=[[University Corporation for Atmospheric Research]]|url-status=live|archive-url=https://web.archive.org/web/20030320222147/http://www.meted.ucar.edu/resource/soo/MesoAnalyst.htm|archive-date=2003-03-20}}</ref> [[Entrainment (meteorology)|Movement]] of dry air into strong thunderstorms over continents can increase the frequency of hail by promoting evaporational cooling, which lowers the freezing level of thunderstorm clouds, giving hail a larger volume to grow in. Accordingly, hail is less common in the tropics despite a much higher frequency of thunderstorms than in the mid-latitudes because the atmosphere over the tropics tends to be warmer over a much greater altitude. Hail in the tropics occurs mainly at higher elevations.<ref>{{cite book |first1=Thomas E. |last1=Downing |first2=Alexander A. |last2=Olsthoorn |first3=Richard S. J. |last3=Tol |title=Climate, change and risk |url=https://books.google.com/books?id=UbtG3vFfNtoC |access-date=2009-07-16 |year=1999 |publisher=Routledge |isbn=978-0-415-17031-4 |pages=41–43}}</ref>

Hail growth becomes vanishingly small when air temperatures fall below {{cvt|-30|C|F|0}}, as supercooled water droplets become rare at these temperatures.<ref name="mesoanal"/> Around thunderstorms, hail is most likely within the cloud at elevations above {{cvt|20000|ft|m}}. Between {{cvt|10000|ft|m}} and {{cvt|20000|ft|m}}, 60% of hail is still within the thunderstorm, though 40% now lies within the clear air under the anvil. Below {{cvt|10000|ft|m}}, hail is equally distributed in and around a thunderstorm to a distance of {{cvt|2|nmi|km}}.<ref>{{cite web |url=http://www.skybrary.aero/bookshelf/books/163.pdf |title=Flight Briefing Notes: Adverse Weather Operations Optimum Use of Weather Radar |page=2 |website=SKYbrary.aero |publisher=Airbus |date=2007-03-14 |access-date=2009-11-19  |archive-url=https://web.archive.org/web/20110531151540/http://www.skybrary.aero/bookshelf/books/163.pdf |archive-date=2011-05-31}}</ref>