Extreme Temperature Diary- May 22nd, 2018/ Topic: Early Tropical Trouble

Tuesday  May 22nd… Dear Diary. The main purpose of this ongoing post will be to track United States extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials)😊. Here is today’s main climate change related topic:

Early Tropical Trouble

I have long suspected that with oceans warming due to carbon pollution organized tropical systems are starting to appearing sooner and disappear later, thus expanding tropical seasons worldwide. In the Atlantic Basin the “official”  hurricane season begins June 1st and ends November 1st. What I have witnessed this century leads me to believe that this time frame will need to be expanded. This year we may have another early case potentially causing some damage mainly from flooding in the United States.

National Hurricane guidance and models suggest that a system may organize in the northern Caribbean and/or Gulf of Mexico before June 1st:

745 AM:  A new Special Outlook has been issued.  There is a 40% chance of subtropical or tropical cyclone forming late this week in the central or eastern Gulf of Mexico.  See the full text at:

This morning’s operational GFS has a weak but organized system in the eastern Gulf:
Regardless of whether or not a system gets named there will be plenty of rain occurring across the Southeast leading to localized flooding. As discussed yesterday due to a new dipole pattern what we are seeing here is meteorologically plausible but pretty far away from normal, average late May climatology:
Identifiable May named systems have occurred before but are rare. I saw this information this morning from Hurricane expert Michael Lowry: 

Since 1851, we’ve recorded 32 Atlantic tropical cyclones during the month of May. Most have formed in the western Atlantic or Caribbean, w/ very few in the Gulf. Only 4 hurricanes have been recorded in May, with no May U.S. hurricane landfalls.

The last two years we had early systems, Bonnie as a tropical storm in May 2016, and Bret as a subtropical storm in April 2017.  In fact, during the planets warmest year on record in 2016 we had a January hurricane, Alex. The strangest hurricane season I witnessed was that of 2005 when Greek letters had to be used for named storms well into January of the following year with Tropical Storm Zeta disappearing on January 6th, 2006. Don’t forget 2005 was when Katrina occurred.
Others are taking notice of the early tropical threat this week in context with typical climate. Dr. Marshall Shepherd wrote this piece today: 
From the article:

Lowry’s estimates, using data at this link, include recent years, but a table on the NOAA Hurricane Research Division website counts the number of tropical storms and hurricanes from 1851 to 2015, and it is clear that May storms are somewhat rare but not impossible. Weather Underground provides an excellent list of early season hurricanes by name. Typically, hurricanes form later in the season because it takes the ocean water a bit longer to heat up to required temperatures to support them. I wrote in November about the notion of whether a “hurricane season” is becoming obsolete.

Now let’s peak into Dr. Shepperd’s earlier article indicating why he thinks that having an arbitrary beginning and end of hurricane seasons is becoming obsolete: 
Will there be a lot more catalogued activity on the edge of this chart due to warming seas?
Quoting from the article:

 In a 2016 American Meteorological Society Blog, the question was raised about whether the Atlantic “hurricane season” should be lengthened. The blog pointed out,

In the past decade, half of the Atlantic’s seasons had “preseason” storms. In 2012, two storms—Alberto and Beryl—were named before the season officially started. And last year, Ana formed east of Georgia on May 7. Granted, it was initially a subtropical storm, a hybrid with both tropical features and features of midlatitude cyclones. But waters were warm and Ana became fully tropical in just days, and moved ashore in South Carolina on May 10.

Experts note that the current length was established in 1965 based on the formation dates of 97% of tropical cyclone activity in the basin. However, research published in Geophysical Research Letters by Jim Kossin at the University of Wisconsin found that warming sea surface temperatures were leading to more “pre” and “post” season storms. A more recent study the Journal of Meteorological Research investigated relationships between sea surface temperatures and early onset. A 2017 study in the Journal of Climate found relationships between El Nino and the tropical cyclone season onset in the Pacific basin. Such research and “common sense” observations of what is happening recently suggest that continued research into roles of natural variably and possible human-related is warranted.

Dr. Marshall Shepherd, Dir., Atmospheric Sciences Program/GA Athletic Assoc. Distinguished Professor (Univ of Georgia), Host, Weather Channel’s Popular Podcast, Weather Geeks, 2013 AMS President

This week will be interesting. I will post updates as warranted.

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The Climate Guy

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