Watching for Tropical Stirrings in the Caribbean May 20th - June 5th

By: Levi32 , 7:46 PM GMT on May 10, 2012

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The time of year has come to start watching for our first tropical system to form in the Atlantic. The period from May 20th through June 5th is starting to look favorable for monsoonal activity to invade the western Caribbean and move north or northeast into the eastern Gulf of Mexico or the Bahamas. Convection should be enhanced in the area by a Madden-Julian Oscillation (MJO) pulse coming eastward into the eastern Pacific and western Caribbean in a couple of weeks. The model MJO forecasts below show the GFS being the most bullish, which is not surprising.



In fact, the GFS showed this happening 3 weeks ago. I don't mean that it saw this event 3 weeks in advance. I mean that saw it happening way too early, and that is a model failing. Indeed, the GFS has been showing a tropical storm in the western Caribbean on almost every run for 3 weeks now in the western Caribbean, which until now has made no sense. However, it is worth mentioning now, because the pattern is more supportive for this to occur. A slower MJO progression as shown by the European models is called for, indicating that at some point during the May 20th-June 5th period we should see a pickup in tropical thunderstorm activity in the Caribbean that could lead to an early storm. This is this morning's 12z GFS run's depiction of the storm at Day 11, which may still be a bit too early:



Additionally, the upper pattern around this time is looking suspicious for tropical activity. The GFS ensembles have the polar jet retreating into southern Canada, with general ridging over the central and eastern United States. However, 500mb heights consistently sag south and east of the U.S., with a weak trough of some kind hanging back and reaching into the NW Caribbean, a pattern indicative of upward motion occurring in the tropics, and a trough becoming involved in the monsoonal circulation in the early season is a good way to get a quick tropical storm that gets drawn out of the Caribbean.



Now this is still nearly 2 weeks out, so details will be scarce until the time draws nearer, but if we do get some kind of a development, expect it to be drawn out of the western Caribbean northward into either the eastern Gulf of Mexico or across Cuba into Florida or the Bahamas, but likely being sheared to the east as it goes, typical of early-season systems. If anything the pattern should turn wet for these areas, hopefully bringing needed tropical rains to Florida. It is also possible that the eastern Pacific will see activity and possibly their first storm before the Atlantic has a chance to see any action. The time has come to start monitoring the tropics again.

We shall see what happens!

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13. LakeWorthFinn
11:08 PM GMT on May 10, 2012
Thanks Levi, good to have you here :)
Member Since: October 6, 2005 Posts: 67 Comments: 7198
12. Levi32
10:30 PM GMT on May 10, 2012
Quoting TropicalAnalystwx13:
Thanks for the tidbit Levi.

Do you know any analogue tropical cyclones off the top of your head that developed in this type of pattern?

Just curious.


Well there's a few. It's a pretty typical pattern. Among recent ones were Alberto in 2006, Arlene in 2005, and Allison in 1995.
Member Since: November 24, 2005 Posts: 628 Comments: 26455
11. TropicalAnalystwx13
9:58 PM GMT on May 10, 2012
Thanks for the tidbit Levi.

Do you know any analogue tropical cyclones off the top of your head that developed in this type of pattern?

Just curious.
Member Since: July 6, 2010 Posts: 108 Comments: 30251
10. seflagamma
9:55 PM GMT on May 10, 2012
Levi,
Thanks for the update. Will be coming here often I am sure.


Quoting Grothar:
Nice one. Levi. I hope you are right. We need the rain here badly.


Hi Grothar, I know you live here in Broward where I do but I have had rain 3 days in a row now. Yesterday I dumped .65" during lunch break from prev 24 hrs.. have not looked at gauge since yesterday at lunch time..but some heavy rain out here...

But Broward is funny, some places get heavy rain and some places never get rain... we are "green" on the moisture Map... or we were earlier...

Just a quick check in and saw Levi's update and had to come what was going on..
Hi everyone!
Member Since: August 29, 2005 Posts: 294 Comments: 40839
9. PakaSurvivor
8:44 PM GMT on May 10, 2012
Wow, are we already on the approach pattern for the tropical season. This year is flying by too quickly. Thanks for the information.
Member Since: September 20, 2010 Posts: 0 Comments: 235
8. mermaidlaw
8:20 PM GMT on May 10, 2012
Thank you Levi for another great tropical tidbit. It is good to see you.
Member Since: July 23, 2006 Posts: 20 Comments: 8736
7. Tropicsweatherpr
8:09 PM GMT on May 10, 2012
Thanks for that great discussion.
Member Since: April 29, 2009 Posts: 75 Comments: 13293
6. wunderkidcayman
8:09 PM GMT on May 10, 2012
good one hey btw you forgot to talk about the noaa's FIM model which is with the gfs and I also hear that the NOgap was at one point in on this with at end of run placing a low where gfs has it at the same or close to time frame
Member Since: June 13, 2009 Posts: 2 Comments: 9557
5. hydrus
7:57 PM GMT on May 10, 2012
Thank you for the update. Models want something in the Western Caribbean. We shall see.
Member Since: September 27, 2007 Posts: 1 Comments: 19523
4. MAweatherboy1
7:57 PM GMT on May 10, 2012
Thanks Levi... As Grothar said anything that develops would be much appreciated in Florida.
Member Since: February 11, 2012 Posts: 79 Comments: 7295
3. nigel20
7:55 PM GMT on May 10, 2012
Thank you again Levi for an indepth update
Member Since: November 6, 2010 Posts: 9 Comments: 7459
2. Grothar
7:55 PM GMT on May 10, 2012
Nice one. Levi. I hope you are right. We need the rain here badly.
Member Since: July 17, 2009 Posts: 63 Comments: 23710
1. AtHomeInTX
7:55 PM GMT on May 10, 2012
Thanks Levi. :)
Member Since: August 24, 2010 Posts: 0 Comments: 459

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About Levi32

Levi Cowan has been tracking tropical systems since 2002, and is currently working on his bachelor's degree in physics at UAF.

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