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 , 1:27 PM GMT on July 14, 2010
Tropical Storm Conson hit the Philippines' main island of Luzon yesterday as a strong tropical storm with 70 mph winds. Conson was briefly the season's first typhoon on Monday, when it intensified to an 80 mph Category 1 storm. Conson is being blamed for at least 18 deaths in the Philippines, with 57 other people missing. The storm caused an extended power outage to the entire island of Luzon. Conson is headed towards a second landfall later this week in China, but should not intensify into a typhoon again because of the presence of 20 - 30 knots of wind shear. Conson is only the second named storm in what has been an unusually quiet Northwest Pacific typhoon season. According to Digital Typhoon, an average season has six named storms by mid-July.
Figure 1. Tropical Storm Conson as captured by the MODIS instrument on NASA's Aqua satellite at 4:55 UTC July 13, 2010. At the time, Conson was a tropical storm with sustained winds of 70 mph. Image credit: NASA.
June SSTs in the tropical Atlantic set a new record
Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes had their warmest June on record, according to an analysis I did of historical SST data from the UK Hadley Center. SST data goes back to 1850, though there is much missing data before 1910 and during WWI and WWII. SSTs in the Main Development Region (10°N to 20°N and 20°W to 80°W) were 1.33°C above average during June, beating the previous record of 1.26°C set in June 2005. June 2010 is the fifth straight record warm month in the tropical Atlantic, and the third warmest anomaly measured for any month in history. The only warmer anomalies were 1.51°C and 1.46°C, set in May 2010 and April 2010, respectively. As I explained in detail in a post on record February SSTs in the Atlantic, the Arctic Oscillation (AO) and its close cousin, the North Atlantic Oscillation (NAO), are largely to blame for the record SSTs, though global warming and Atlantic Multidecadal Oscillation (AMO) also play a role. The magnitude of the anomaly has fallen over the past month, since trade winds over the tropical Atlantic have increased to slightly above-normal speeds. These higher trade wind speeds are due to the fact that the Bermuda-Azores High has had above-normal surface pressures over the past month. The Bermuda-Azores High and its associated trade winds are forecast to remain at above-average strength during the next two weeks, according to the latest runs of the GFS model. This means that Atlantic SST anomalies will continue to fall during the remainder of July. However, keep in mind that we are talking about anomalies--the ocean will continue to warm until its usual early September peak in temperature, and it is likely that we will have the warmest or second warmest SSTs on record over the tropical Atlantic during the peak part of hurricane season, mid-August through mid-October.
Figure 2. The departure of sea surface temperature (SST) from average for July 12, 2010. Image credit: NOAA/NESDIS.
The tropics are quiet
There are no threat areas to discuss in the tropical Atlantic today, and none of the reliable computer models is calling for tropical cyclone development over the next seven days. The NOGAPS model is calling for a strong tropical disturbance to form off the Nicaragua coast this weekend. If this disturbance forms, it would move west-northwest and bring heavy rains to Nicaragua and Honduras early next week.
I'll have a new post on Thursday.
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