Tuesday, May 10, 2011

Summer/Tropical Outlook, Abridged version

If I wait until I have 2 hours to compose a full version then it will be autumn.  Here is an brief summer and tropical outlook.  More details will follow mixed into upcoming articles.

Important pattern details:
  • Weakening La Nina/generally rising AAM through much of the summer: This combination favors a general trough in the eastern US which will contrast greatly with last summers mega-ridge that roasted the region.
Cold anomalies are warming in all zones
Source: NOAA Climate Prediction Center

  • Resurgent Madden-Julian Oscillation:  The 40 day wave through the tropics correlates well with temperature and precipitation patterns when it is observed correctly.  It can also be useful when combined with other tools with forecasting bias in the paths and strength of tropical systems.
MJO has strengthened into a trackable feature
Source: The Center of Australian Weather Research

  • Inland Upper Tropospheric Trough: I hesitate to call it a TUTT (Tropical Upper Tropospheric Trough) but the abnormally high rainfall storms and clash of cold and warm between the Mississippi River and Appalachians this spring will lead to an upper level cool pool reminiscent of recent years like 1996, 1999, and to some extent 2003.  Most of us know what happened when the hurricanes came during those years.  The orientation and positioning of that feature will be huge in regards to who takes the 1-3 serious storms that will be coming.
What to expect:
  • Cool to Moderate Temperatures:  This is the summer that we have been waiting for!  Yes, NC and VA summers even when near average are hot ... BUT ...  I will accept this one over the fiery furnace of last year.  My instinct tells me that the biggest heat will  be in the midsummer near July 4th.
  • Regular Precipitation but... :  Rising AAM means more frequent frontal passages.  Therefore rain will be in regular intervals.   The big but...  comes in August/September as falling AAM brings the tropical moisture plume and storms to menace the eastern seaboard.
  • Hurricanes:  If I may continue my winning streak into a 3rd year.  Careful study has led me to believe that average hurricane path will yield landfalls from the FL Panhandle to New England.  If correct, the winter implications would be for real winter storms to menace the same region....
Some details will follow in future  articles.  Enjoy the summer!  Except for drama at the end most of it will be great!

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