World_Aug_2017_6hr
--August is the last month of meteorological summer in the Northern Hemisphere, and of winter in the Southern Hemisphere. --By tracking the latest hours in white, the overhead sun can be seen moving east to west on a daily basis. --Thunderstorms travel west to east over the middle and higher latitudes in both hemispheres, and are stationary or move more slowly from varying directions in the tropics. ~Ron Holle
Sep 6, 2017 Webmaster Archive
Northern Hemisphere --Canada, China, Europe, the Indian subcontinent, and Russia have frequent lightning all month. --August lightning over the United States is frequent, in clusters and lines across the entire country, except lesser activity in the northwest states. --The North American Monsoon accounts for daily lightning over much of northwest Mexico and the southwest U.S. --Thunderstorms form to the south and north of the Himalayas on most August days. ~Ron Holle
Sep 8, 2017 7:45:44 PM Dave Fincher
Tropics --The east-west aligned equatorial trough, the Intertropical Convergence Zone, is intermittently organized over the Atlantic, and the eastern and central North Pacific. --The major islands and land areas of tropical Southeast Asia have thunderstorms nearly every afternoon in sea breezes and along mountain slopes. Motion is variable near the equator. --Lightning over Africa is mostly between the Equator and the central Sahara until it starts to spread southward later in August. --A steady progression of easterly waves forms over equatorial Africa that move west to the Atlantic coast at intervals of three to five days. --Thunderstorms over Brazil are confined to its northern third until spreading southward later in August. --Central America and Mexico have frequent lightning. ~Ron Holle
Sep 8, 2017 7:45:55 PM Dave Fincher
Southern Hemisphere --Several storms form over South Africa, Australia, and Argentina and move offshore to the east. --Organized thunderstorms move steadily from west to east across the southern oceans. --The Andes south of the equator provide a sharp western boundary in a NNW-SSE line and no lightning occurs over the cold water offshore of the Andes. ~Ron Holle
Sep 8, 2017 7:46:21 PM Dave Fincher
Specific --01 to 15 August: A continuous line of thunderstorms extends from the Yucatan Peninsula to the Atlantic east of Bermuda. --04 to 07 August: Isolated cyclonic circulation over western Turkey. --13 to 15 August: Long thin line of lightning over north-central Russia, simultaneously with a cyclonic circulation to its south. --16 to 28 August: Hurricane Harvey travels across the Caribbean Sea, the Yucatan peninsula, and onto the coast where Houston had massive flooding from 25 to 28 August. --23 to 24 August: The circulation of Typhoon Hato moves northwest to over southern China. --26 to 29 August: Isolated stationary cyclonic circulation covers Spain and Portugal. --26 to 29 August: Large cyclonic circulation prevails over India. --28 to 31 August: The circulation of Typhoon Sanvu is east of Japan. ~Ron Holle
Sep 8, 2017 7:46:40 PM Dave Fincher