Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 5:13 PM GMT on July 15, 2011
June 2011 was the globe's 7th warmest June on record, according to the National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center (NCDC). NASA's Goddard Institute for Space Studies rated June the 8th warmest on record. June 2011 global land temperatures were the 4th warmest on record, and ocean temperatures were the 10th warmest on record. Global satellite-measured temperatures for the lowest 8 km of the atmosphere were well above average, the 5th or 3rd warmest in the 34-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH). Ocean temperatures in the Atlantic Main Development Region for hurricanes, from the coast of Central America to the coast of Africa between 10°N and 20°N, were 0.9°C above average, the 5th warmest such temperatures in the past 160 years. The record was set in 2010, with a temperature of 1.3°C above average.
Figure 1. Departure of temperature from average in June 2011. Image credit: National Climatic Data Center (NCDC).
Record cold temperatures in the stratosphere
Global temperatures in the lower stratosphere, where the bulk of Earth's protective ozone layer lies, were at their coldest levels on record during June, according to both the University of Alabama and RSS, Inc. This is the second consecutive month of record cold in the stratosphere. Global warming theory predicts that in order to counter-balance the large amount of warming that occurs in the lower atmosphere near the surface when heat-trapping gases such as carbon dioxide are released into the air, the stratosphere must cool. Thus, a record cold stratosphere is consistent with global warming. However, the majority of the stratospheric cooling that has occurred since the 1990s is probably due to destruction of ozone by chlorine-containing gases like CFCs. Ozone strongly absorbs solar energy, warming the air around it, so if there is less ozone around, there will be less absorption of solar energy and a thus a cooler stratosphere.
Earlier this year, the World Meteorological Organization announced that depletion of the ozone layer—the shield that protects life on Earth from harmful levels of ultraviolet rays—reached an unprecedented level over the Arctic this spring because of the continuing presence of ozone-depleting substances in the atmosphere, and a very cold winter in the stratosphere. The Arctic ozone declined 40% between December and March.
U.S. heat wave to last at least another week
An unusually intense, widespread, and long-lasting heat wave over the majority of the U.S. continues to set numerous daily record highs. The latest long-range forecasts from the GFS and ECMWF models predict that the ridge of high pressure entrenched over the country responsible for the heat wave will move little over the coming week, and the heat wave should continue for all but the Pacific Northwest through July 23. The GFS model does show that the ridge will break down some during the period 10 - 16 days from now, but such long range forecasts have low skill, and the heat wave could easily remain entrenched over the country through the rest of July. I'll present a more detailed look at the heat wave next week.
Figure 2. Typhoon Ma-on at 04:15 UTC July 15, 2011, over the West Pacific Ocean. The small swirl at lower left is Tropical Depression Tokage. Image credit: NASA.
Typhoon Ma-on headed towards Japan
Powerful Category 4 Typhoon Ma-on is headed westward over the West Pacific Ocean, but is expected to encounter a trough of low pressure this weekend that will recurve the storm to the north and northeast, bringing it very close to the coast of Japan early next week. With water temperatures along the path of the typhoon ranging from 28 - 30°C, and wind shear expected to remain in the moderate range, 10 - 20 knots, Ma-on has the potential to hit Japan as a major Category 3 storm.
The Atlantic is quiet
None of the reliable models predict tropical cyclone development through July 21.
I'll have a new post by Monday at the latest.
Jeff Masters and Angela Fritz
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