Early June Development in WCarib or BOC? (Is Invest 91L)

[TropicalAnalystwx13]

The strong MJO pulse responsible for the [soon-to-be] twin cyclones in the Indian Ocean (one in the northern hemisphere, one in the southern hemisphere) is forecast to steadily work its way through the Maritime Continent, West Pacific, and eventually reach Octants 8/1 (West Hemisphere, Atlantic/East Pacific) by the end of the month. Many of the global computer models—especially the GFS—are hinting at lowering pressures across the eastern Pacific and western Caribbean. The CMC shows "Alvin" developing in a little over a week's time now, while the GFS ensembles have a low-pressure center in the western Caribbean by the end of their runs. While specifics -- intensity, track, etc -- are obviously unknown, MJO pulses in the early season make up over three-quarters of the cyclone development method. One of this magnitude means it's likely we see "Alvin" and "Andrea" by the end of the first week of June, if not sooner.

[Ntxw]

I concur with everything TropicalAnalystwx13 said. This is a very strong MJO well supported by the recent mountain torque event and suspect the models are not handling well yet the progression of it beyond the western Pacific. Monsoon-like areas of convection will likely awaken on either side of Central America later this month. The last of the Canadian highs will settle over the eastern US and set up nice return/moist flow into the carib-southern gulf regions likely reducing shear and various other factors that so far have prevented formation of early season systems.

[JonathanBelles]

I concur with everything TropicalAnalystwx13 said. This is a very strong MJO well supported by the recent mountain torque event and suspect the models are not handling well yet the progression of it beyond the western Pacific. Monsoon-like areas of convection will likely awaken on either side of Central America later this month. The last of the Canadian highs will settle over the eastern US and set up nice return/moist flow into the carib-southern gulf regions likely reducing shear and various other factors that so far have prevented formation of early season systems.

What do you mean by the highlighted portion above?

[crownweather]

Latest GFS now gets our low pressure system going at about 300 hours. My opinion is that it may be about a week too fast & think that any tropical development may hold off until just after Memorial Day instead of the time period just before Memorial Day.

[kunosoura]

00z GFS still supporting Caribbean action starting May 22ish.



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[cycloneye]

This is from Dr Jeff Masters:

It's worth mentioning that the active pulse of the Madden Julian Oscillation is expected to reach the Western Caribbean sometime May 22 - 26, and there will be a heightened chance of an early-season tropical storm forming in the Eastern Pacific and Western Caribbean during that time period.

[cycloneye]

I would use a blend of faster GFS vs slower ECMWF and get the timeframe shorter than 144 hours to then join the developing bandwagon. For entertainment here is the long range GFS.

[Ntxw]

What do you mean by the highlighted portion above?

This MJO wave is being enhanced (as is with most strong waves) by westerlies that have recently been aided by the mountain torque events (+AAM). Two things usually happens as a result, first is the wave is stronger than what the models predicted a couple of weeks ago and second the MJO is very likely to continue its progression into the western hemisphere instead of weakening once it crosses the Pacific into the Americas as it usually does due to these enhanced westerlies as currently being forecasted by the globals.





As you can see the MJO is most active when MT events are given off to positive territory.

[tolakram]

Every year we get the GFS telling us of development in the southwest Caribbean in mid to late May. IMO this is most likely the first or second EPAC storm.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[cycloneye]

Every year we get the GFS telling us of development in the southwest Caribbean in mid to late May. IMO this is most likely the first or second EPAC storm.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

GEM aka CMC was the first model to sniff development in EPAC a few days ago and now GFS and to some extent the ECMWF are showing it.

[WeatherGuesser]

So far, none of these threads have worked out as touted. I really wish we'd hold off on the long range dramatics and wait until there's something relevant to talk about.

[Frank2]

I'd have to agree - right now we have very strong shear over Florida, so anything that did form would end up a exposed LLC...

A lot would have to change for it to become an issue for the USA, however those who live in Central America, Jamacia or Cuba might need to be prepared as the month progresses, just in case...

Frank2

[TropicalAnalystwx13]

Every year we get the GFS telling us of development in the southwest Caribbean in mid to late May. IMO this is most likely the first or second EPAC storm.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

The model probably didn't have much consistency between runs. It makes sense to see a tropical cyclone in the Caribbean by the first of June. Strong MJO pulse with high pressure over the Eastern Seaboard. The CMC has above-average precipitation in the region as well, which gives the solution a bit more credence.

I'd have to agree - right now we have very strong shear over Florida, so anything that did form would end up a exposed LLC...

A lot would have to change for it to become an issue for the USA, however those who live in Central America, Jamacia or Cuba might need to be prepared as the month progresses, just in case...

Frank2

It doesn't take much to lower wind shear. An anticyclone over any system in the western Caribbean would dramatically lessen the shear values.

[TropicalAnalystwx13]

18z GFS.

[psyclone]

absent some sat pics showing some disturbed weather (the carib is clear) this really is a modelstorm thread.

[gatorcane]

Below graphic bottom row shows essentially what others have been saying regarding the potential for a strong MJO pulse across the Western Caribbean for the end of the month:

[psyclone]

this set up would seem to imply at least northerly advection of deep caribbean moisture to jump start the florida rainy season.

[JonathanBelles]

Below graphic bottom row shows essentially what others have been saying regarding the potential for a strong MJO pulse across the Western Caribbean for the end of the month:

Image Omitted

Wow! I don't think I have seen white on the "wet" side of the scale before.

[psyclone]

I've never seen the white either...only a dark green max out. and it's a big area too.

[cycloneye]

Well,GFS is dancing around as the 00z run only had a weak TD instead of a Tropical Storm and the 06Z run had a Tropical Storm. And also still no other models are showing it as of Saturday morning so there is a big deal of uncertainty at this time. Let's see how things evolve in the model world in the coming days.