Hurricane in Western Caribbean?

[wxman57]

one thing to remember, you often need a pressure of ~1000mb to have a TD in this part of the basin this time of year

I was curious so I looked back at some saved analysis charts for a few storms. I have an analysis chart from the day Wilma developed and pressures in the region are 1005-1007mb. Well, here it is:

Wilma Developing - same area:


Oh, found one from before Paloma developed, too. 1010mb:


I see similar pressures in the region for Michelle (2001) but didn't save a chart before it became a hurricane.

[Derek Ortt]

on the first advisories of those two storms, as 25KT TDs, the pressures were already 1004mb. Wilma only became a minimal TS at 1000mb

Models may need to show lower pressures before we get excited about TC formation

[wxman57]

on the first advisories of those two storms, as 25KT TDs, the pressures were already 1004mb. Wilma only became a minimal TS at 1000mb

Models may need to show lower pressures before we get excited about TC formation

Oh, I'm looking at the environmental pressures in the region prior to formation, not the initial central pressure of any depression/storm. The environment in the Caribbean now is similar, pressure-wise, to the conditions prior to past October/November developments. Look at the ambient pressure around Paloma as it began to develop - 1010-1011MB all around the low. And I'd wager that 3-4 days before Wilma or Paloma developed, the pressures across the western Caribbean were even higher than what we're seeing out there now. The GFS and Euro forecasts of 1007 mb central pressures will be off, of course, as they're not good at predicting such things. Once (if) a low starts to form, its pressure will drop very quickly to much lower than the ambient environmental pressure of the region.

[Evil Jeremy]

Convection waning this morning. Its still there, but lessening.

[wxman57]

Pressure around 1009MB in the SW Caribbean now. Some evidence of a broad low. Convection disorganized. At least 2-3 days away from a TD, if it develops.

[HURAKAN]

Classic late season development in the Caribbean. It takes time but usually something forms.

[Sanibel]

Cold dome on top:

[Evil Jeremy]

I would not say that this is invest worthy at this point (though this has more potential than many of this year's invests) but it should be a Code Yellow.

[wxman57]

I would not say that this is invest worthy at this point (though this has more potential than many of this year's invests) but it should be a Code Yellow.

Code yellow is for potential development within 48 hours. Development, in this case, may be in the 72-96 hour range. So maybe a code yellow would be appropriate in another 24-36 hrs.

[Evil Jeremy]

I would not say that this is invest worthy at this point (though this has more potential than many of this year's invests) but it should be a Code Yellow.

Code yellow is for potential development within 48 hours. Development, in this case, may be in the 72-96 hour range. So maybe a code yellow would be appropriate in another 24-36 hrs.

There have been Code Yellows though that have said "development is not expected within the next 48 hours", and not just for systems dieing out, but systems that could potentially develop down the road.

[Sanibel]

I would guess the negative conditions are still there and will eat into it.


Perhaps it is close enough to Rick's category 5 favorability zone to form?

[HURAKAN]

They're smelling something!!

[wxman57]

I would not say that this is invest worthy at this point (though this has more potential than many of this year's invests) but it should be a Code Yellow.

Code yellow is for potential development within 48 hours. Development, in this case, may be in the 72-96 hour range. So maybe a code yellow would be appropriate in another 24-36 hrs.

There have been Code Yellows though that have said "development is not expected within the next 48 hours", and not just for systems dieing out, but systems that could potentially develop down the road.

There's a difference between development "not expected" and development "not possible" in the next 48 hours. Every code yellow means that development is not expected, as chances are much greater that it won't develop (70+% chance it won't develop). The yellow, orange and red classifications are for potential development within 48 hours. They say nothing about development beyond 48 hours. So if the chances are close to zero for the next 48 hours, it doesn't warrant a yellow.

[Blown Away]

I guess if we are hanging our hat on the few models that show development a Code Yellow is not warranted, because the models don't show anything within the next 48 hours. I still think this area should be Code Yellow.

[wxman57]

I guess if we are hanging our hat on the few models that show development a Code Yellow is not warranted, because the models don't show anything within the next 48 hours. I still think this area should be Code Yellow.

If you think that this system should be "code yellow", then you've already calculated the probability of it developing within 48 hours. So, what do you estimate are the chances that this will be upgraded to a TD by noon Wednesday? (anyone else here may reply).

Not a trick question, just an honest inquiry. What is the 48hr probability of this becoming a TD?

[Ivanhater]

00Z Canadian



Nogaps

[wxman57]

I have the GFS in through 180 hrs now. It develops a low in the SW Caribbean on Saturday and moves it due west into southern Nicaragua around noon on Monday. Here's the map from Sunday afternoon:

21Z Sunday:


18Z Monday:

[AtlanticWind]

I guess if we are hanging our hat on the few models that show development a Code Yellow is not warranted, because the models don't show anything within the next 48 hours. I still think this area should be Code Yellow.

If you think that this system should be "code yellow", then you've already calculated the probability of it developing within 48 hours. So, what do you estimate are the chances that this will be upgraded to a TD by noon Wednesday? (anyone else here may reply).

Not a trick question, just an honest inquiry. What is the 48hr probability of this becoming a TD?

I would put this in the 5 to 10 percent range in the next 48 hours .and maybe 5o percent in the next 5 days , should that warant a code yellow? I dont know its kind of subjective.

[Derek Ortt]

seems like it is developing a Katrina 1999

[wxman57]

I would put this in the 5 to 10 percent range in the next 48 hours .and maybe 5o percent in the next 5 days , should that warant a code yellow? I dont know its kind of subjective.

Yes, it is subjective. There probably is a lower limit to the code yellow probability, but I don't know what it is. Would a 10% chance warrant yellow? 5%? 1%? 0.1%?

I would agree that the chances are not zero of this being classified as a TD within the next 48 hours. My estimate would be less than 5%, maybe 2%. Does that warrant a yellow, just a 2% chance?