I'm a CMU Honors student and love meteorology and extreme weather. I've been fascinated by weather since I was 5, and plan on becoming a meteorologist
By: wxchaser97 , 7:15 PM GMT on May 25, 2013
We are almost to June 1st, the start of the Atlantic hurricane season. While there is nothing of interest in the Atlantic right now, that could change in the coming weeks. It has been known for a couple weeks that development in the northwest (NW) Caribbean would be possible during the last few days of May through the first week of June. A MJO pulse is expected to swing through the Caribbean at that time. This would increase moister and lift which would help promote tropical cyclone development. Most of the models bring it into our basin, besides the ECMWF. All the models, and their ensembles, show development of at least a monsoonal low in the NW Caribbean. We should monitor trends in the ensemble runs and the operational runs to see where any storm would develop. Focusing on just the operational runs isn't good because they are going to be flipping all over the place. The ensemble mean will tell us what is being consistent. Lets take a look at the 12z GFS ensembles, the 00z CMC ensembles, and the May 24th 12z ECMWF ensembles.
We can see some pretty interesting things here. At first glance it might not look like much, but there is some pretty telling things going on in these images. We see on the GFS a closed 1006mb low in the NW Caribbean. Pressure is below normal as well in the NW Caribbean. The CMC ensembles also show some lower pressures and a low. The ECMWF ensembles too show a low pressure developing. We have a pretty good consensus of lower pressure in the NW Caribbean about 10 days from now. While it is 10 days out, it has been moving forward in time. Development used to be shown at the 384hr mark, which tends to be ghost storms. This was evident on the operation GFS. It was showing a TS in the Caribbean past 300hrs since the beginning of May. Just over the past week has it moved up in time with develop. The operational GFS and CMC are also more bullish in intensity. I expect them to continue to flip flop and be bullish for a little while longer as they try to resolve the pattern in the NW Caribbean.
I am expecting a monsoonal low to begin to develop in the NW Caribbean in late May. Whether this turns into something tropical remains to be seen. Right now I can't say how strong it would get and where it would go if something did develop. Conditions will be favorable in the NW Caribbean in the coming weeks. Upper level riding should develop in the GOM which should reduce winds shear. Shear may become a problem, however, if it goes farther north. SST's are AOA normal and have been warming up over the past 7 days. One of the biggest hindrances to development will be time. Whether a circulation can wrap up into a TC before getting into less favorable conditions or interacting with land. It is still too far out to known if that will happen. No matter what a rainy pattern will take hold in the Caribbean and SE US as the MJO swing through. Here is an image that reflects my thoughts.
Have a great Memorial Day Weekend everyone. For anyone who hasn't seen my blog from last night, here is my Moore tornado recap and Berkley, MI tornado safety blog. I plan on doing my 2013 hurricane season forecast blog over the next couple days. I also plan on doing an EPAC tropical update. Thanks for reading.
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