Global Model Runs for W.Caribbean Early Season Development

[Ed Mahmoud]

ECMWF develops a EPAC system, that by 240 hours has weakened as it heads due North across Central America. Just extrapolating, with minor -removed-, although we could use the rain here near Houston, it should eventually feel the Westerlies and bend towards Florida, providing beneficial rainfall that breaks the mini-drought, with the now re-moisturized Everglades providing a little extra support for EC and WC sea breeze storms that bring rain as far North as the Daytona area, ensuring wildfires don't cancel this years Fourth of July weekend Coke Zero 400 NASCAR Sprint Cup race.

[Ivanhater]

What I notice is the same thing that happens every year around this time, the models produce the south-west Caribbean storm for the early June period.

I thought the models don't show strength very well so I wouldn't say it's very weak. It was showing the same for Dean when it was a category 4.

Exactly the point I made before..GFS doesnt show the true strength of a system, certainly when the resolution is poor 200 hours out..it actually shows a decent storm at about 270, very nicely wrapped..

[Ed Mahmoud]

Its all (almost good) anyway. If it makes it to the US, there are few places along the Gulf Coast that couldn't use a good rain, and with late May/early June marginal SSTs, it probably wouldn't even be hurricane strength.


As long as it doesn't stall/meander ala Allison or get pulled into an intense and unseasonally cold East Coast trough ala Agnes, that it.

[KWT]

Well the 18z GFS still develops the Caribbean system however it also this time develops a system out in the EPAC and looks like it becomes quite strong as well...meanwhile SW Caribbean system doesn't get as strong according to the GFS and tracks NNE towards Cuba then ENE towards S.Florida before exiting for a while...then swinging back westwards into Florida. I bet that would be an ideal set-up for those who have had little rainfall in May so far.

[Ivanhater]

Crazy scenario on this run..goes to eastcoast of Florida before coming back in around Miami then enters the gulf..

Coming into Miami..


In the Gulf...

[JonathanBelles]

Dancing with the Blobs?

[Dean4Storms]

BEARS Watching!

[MiamiensisWx]

What I notice is the same thing that happens every year around this time, the models produce the south-west Caribbean storm for the early June period.

I thought the models don't show strength very well so I wouldn't say it's very weak. It was showing the same for Dean when it was a category 4.

I concur with the supposition in the bolded portion. The GFS' input is taking seasonal changes into account, which is reflected in the output and surface reflection depictions in the runs. June TC formation in the favored northwestern Caribbean Sea is not an unprecedented circumstance. This is strongly related to climatology, so the operational GFS may not actually "pick up" something in these runs. In other words, the solution will likely not verify.

[JonathanBelles]

I'm glad this isnt august-October.

[Steve]

>>Personally I don't think any MET should be talking about a tropical disturbance for the Jun 1st timeframe when its more than 10+ days out, if it even happens.

Why not? It's seems as though that would be his or her job. Admittedly there is uncertainty with long range models, but I actually appreciate someone who isn't afraid to discuss possibilities. That's one of the reasons I view this and other tropical wx forums.

[jimvb]

I agree with Steve. The forecast for a specific day may not come out as what distant GFS shows. But it still is like a distant truck on a two-lane road coming towards you. You can make a reasonable prediction that a truck will come by you on your left in a minute or two; at least that is what it looks like up ahead. It may not happen; the truck could pull into a gas station, turn right, or do something else before reaching you. But at least the possibility is still there. The same with the GFS.

And maybe the Gulf needs the rain, but Virginia sure doesn't! We have had rainstorm after rainstorm this spring with 2-3 inch rains, poweroutageproducing winds, and tornadoes that blow cars around like a kid throwing matchbox cars. The lawns are all green, and you need a life jacket to wade into the James. If a strong storm comes, trees are more likely to blow down because their root systems are weakened by all this rain; a situation similar to Henri followed by Isabel. So keep the rain in the Gulf.

[gatorcane]

It is looking increasingly disturbed in the SW Caribbean and EPAC off the coast of Central America

[boca]

This probably doesn't mean much but the 06zGFS is sniffing out development as early as 156hrs.Its alot better than 384hrs.You can see that that area is showing more convection and is persistant down there which gatorcane posted above.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_156m.gif

[KWT]

Yep though note that it doesn't close the system off till about 240hrs still and keeps it as a tropical disturbance till that point, by which time its close to Cuba and in that way the GFS has somewhat eased off from what it was forecasting at first.

Will be interesting to see what the 12z round of models show.

[boca]

Yep though note that it doesn't close the system off till about 240hrs still and keeps it as a tropical disturbance till that point, by which time its close to Cuba and in that way the GFS has somewhat eased off from what it was forecasting at first.

Will be interesting to see what the 12z round of models show.

By the time the 12z comes out I'll be at work. I'll have to look at the 18z model run.

[Ed Mahmoud]

Euro still develops an East Pac system it moves North into Central America. By Day 10 (240 hours), I assume whatever is left is either in the Caribbean or still over land, but the free version of the Euro doesn't have the detail to see it.


Maybe a pro-met (who has access to the more detailed not available to the general public ECMWF output) will weigh in on whether there looks to be enough of the remnants left to regenerate in the Caribbean beyond Day 10.

http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500

[Aric Dunn]

well if we all remember from years past, the gfs although shows some sort of system coming out of the carrib it does not mean it will happen obviously! but my point is that the gfs is good at forecasting potential areas, meaning areas of increased convection or a change in the pattern which could lead to for favorable areas for convection to fire. I have seen it many times over the years and with some fairly good degree of accuracy that far out with at the least the development of convection,and where there is convection there is always a possibility.

[cycloneye]

The 12z GFS starts to show a Western Caribbean system on day 6.

12z GFS at 144 Hours Low Pressure shows up in the 144 hour frame.

5/22/08 12z GFS at 174 Hours

12z GFS at 216 Hours It looks like a lopsided system with the convection displaced.

12z GFS at 264 Hours

12z GFS at 276 Hours

12z GFS Loop Here is the whole 12z run in the loop.It goes all the way NNE paralell to the U.S East Coast.

[Aric Dunn]

lopsided sounds about right this time of year. Barry good example from last year. formed near may 30th

[KWT]

Yep the 12z GFS develops a system as soon as 144hrs on this run though it does slacken a touch within 180hrs the lower resolution part of the run strengthens it again and takes it close to S.Florida at 288hrs.

Certainly the GFS is persitant with this set-up.