Atlantic Tropical Action 2011

[Srain]

NHC Marine MSLP experimental forecast for the W Caribbean does look a bit interesting for later next week, for what it's worth...

[flwxwatcher45]

IMBYism, as posted on subforum thread, I think the upper ridge will be too close for anyplace but Mexico in North America the next 10 days or so. That was about much sea breeze activity, but it should hold for any TCs.

If anything developed.

IMBYism again, I want rain.

Ensemble Euro off Alan's site happier, weakness in ridge over my house, with lowest pressures safely down in SW Caribbean. It isn't wildy different from the operational, but so far this Spring GFS seems to have worked out better locally.

That low just meanders last few days of op Euro run.

Larry Cosgrove seems to think Texas to LA. has a chance for some action in the long range.

I continue to monitor the numerical models, all of which suggest that a genuine tropical disturbance will take shape over the Caribbean Sea next week. Opinions on path and strength are understandably split, but I am inclined to believe that any system which does develop will head into the Gulf of Mexico in the 11 - 15 day time frame. Analog-derived forecasts strongly support a drought-diminishing storm reaching into TX and LA in the middle of June, so do NOT discount this threat. But DO enjoy the Memorial Day weekend!

[Ed Lizard]

GFS ensembles like something (many of them), but where. I'm a little surprised by all the perturbations that like something North of the islands. Looping the ensembles, they all start in the SW Caribbean, but many escape Northward. Maybe I shouldn't be surprised, the ensemble means show 500 mb Westerlies into the Caribbean.

[am19psu]

GFS ensembles like something (many of them), but where. I'm a little surprised by all the perturbations that like something North of the islands. Looping the ensembles, they all start in the SW Caribbean, but many escape Northward. Maybe I shouldn't be surprised, the ensemble means show 500 mb Westerlies into the Caribbean.

The deeper the trough off the Atlantic coast next week, the more likely whatever is down there gets pulled north. That's where the different solutions come in.

[Eyewall2005]

This is what they had to say...

Hi Matt: A few years ago our office looked at the correlation of a dry May in South Florida and a hurricane strike in the same area that hurricane season. No strong correlation was found. Thanks for writing.

There's no scientific correlation between a dry May and an active florida hurricane season. Florida's risk is fairly high every year, regardless of the start of the rainy season, and the weather patterns that cause dryness in May don't necessary translate to or cause another type of weather pattern later in the season that could lead to a South Florida hurricane landfall. In other words, the pattern in late May doesn't usually stick around the entire hurricane season. Even if it did, a tropical system would have to form in just the right place and right time to be affected by that weather pattern and affect South Florida. These things are dictated by weather patterns which can only be reasonably predicted 7 to 14 days out.

[Ed Lizard]

There's no significant scientific correlation between a dry May and an active florida hurricane season. Florida's risk is fairly high every year, regardless of the start of the rainy season, and the weather patterns that cause dryness in May don't necessary translate to or cause another type of weather pattern later in the season that could lead to a South Florida hurricane landfall. In other words, the pattern in late May doesn't usually stick around the entire hurricane season. Even if it did, a tropical system would have to form in just the right place and right time to be affected by that weather pattern and affect South Florida. These things are dictated by weather patterns which can only be reasonably predicted 7 to 14 days out.

Almost intuitive, open to storms from any of three of the 4 cardinal directions, a wide variety of steering patterns during a long part of the season puts Florida at risk.

[Ed Lizard]

The deeper the trough off the Atlantic coast next week, the more likely whatever is down there gets pulled north. That's where the different solutions come in.

New GFS has its cake and eats it, with a weak low in the Caribbean, while a new one calves off it Northeast of Puerto Rico.

(I don't want cake if I can't eat it).

[U_Thant]

Just what we need....Slopgyre II

[am19psu]

Just what we need....Slopgyre II^TM

FYP

[bronxx]

This is what they had to say...

Hi Matt: A few years ago our office looked at the correlation of a dry May in South Florida and a hurricane strike in the same area that hurricane season. No strong correlation was found. Thanks for writing.

I personally have not done a statistical study on this matter, so I don't know what holds true more often: what Jim Lushine noted, or what you have noted.

I do know that Lushine's reputation at the NHC for decades was of the highest order. Although his formal position was in the NWS side of the office, he contributed often to the NHC's reasoning when forecasting, and was considered by most to be one of the most knowledged meteorologists (tropical and otherwise) at the office. He eventually became head of the NWS in Miami.

Now, that doesn't mean his study of May rainfall in S. Florida vs. the coming season's hurricane strikes is "correct"; but it does lead one to assume that he used valid data to come to his conclusion. Are you suggesting or simply assuming he made the data up?

I can only guess that his criteria for calling May a "dry" month might be different than yours (your office). Maybe he only used the very driest of Mays in drawing his conclusion; and some of those years that you (your office) called May "dry" are not included. OR vice-versa.

As a frame of reference:

I do notice in your statement the word "STRONG" correlation: does that mean you found a not so strong correlation? Most, if not all, long term (season long) meteorological correlations do not exceed 60%. If a study comes up with any seasonal forecast correlation over 60%, one has to be extremely suspicious of the study.

---------

My guess, when I first read about Lushine's conclusions in the Miami Herald, was that the cause of the correlation he came to was the idea that in those years that deep easterlies set up early in the "summer" season, they are more likely to be more prevalent during the upcoming months. Hence, when the few hurricanes each year got into "possible striking trajectory" towards S. Florida, the probability of deep easterlies extending past 80 degrees W. at those times were greater than in years when the deep easterlies did not set up so early, or at all.

A correlation/forecast based on persistence. And, as we all know, even Bill Gray's parameters are almost all (if not all) based on certain factors persisting. When they don't, his forecast busts as well.

------------------

Again, though, from my observation, the largest factor in whether a specific area experiences full hurricane conditions in every given year is the factor of pure CHANCE. All other factors pale in comparison; but can be fun to study and one can come up with this percentage or that.

And concerning Lushine's conclusions: I would simply assume that when May is dry in S. Florida, S. Florida is more likely to see a hurricane the coming season, than is those years that May is wet. But, since S. Florida "only" sees a hurricane once every 7 years (or so), it is the "chance" factor that weighs more heavily, and most heavily.

[flwxwatcher45]

I personally have not done a statistical study on this manner, so I don't know what holds true more often: what Jim Lushine noted, or what you have noted.

I do know that Lushine's reputation at the NHC for decades was of the highest order. Although his formal position was in the NWS side of the office, he contributed often to the NHC's reasoning when forecasting, and was considered by most to be one of the most knowledged meteorologists (tropical and otherwise) at the office. He eventually became head of the NWS in Miami.

Now, that doesn't mean his study of May rainfall in S. Florida vs. the coming season's hurricane strikes is "correct"; but it does lead one to assume that he used valid data to come to his conclusion. Are you suggesting or simply assuming he made the data up?

I can only guess that his criteria for calling May a "dry" month might be different than yours (your office). Maybe he only used the very driest of Mays in drawing his conclusion; and some of those years that you (your office) called May "dry" are not included. OR vice-versa.

As a frame of reference:

I do notice in your statement the word "STRONG" correlation: does that mean you found a not so strong correlation? Most, if not all, long term (season long) meteorological correlations do not exceed 60%. If a study comes up with any seasonal forecast correlation over 60%, one has to be extremely suspicious of the study.

---------

My guess, when I first read about Lushine's conclusions in the Miami Herald, was that the cause of the correlation he came to was the idea that in those years that deep easterlies set up early in the "summer" season, they are more likely to be more prevalent during the upcoming months. Hence, when the few hurricanes each year got into "possible striking trajectory" towards S. Florida, the probability of deep easterlies extending past 80 degrees W. at those times were greater than in years when the deep easterlies did not set up so early, or at all.

A correlation/forecast based on persistence. And, as we all know, even Bill Gray's parameters are almost all (if not all) based on certain factors persisting. When they don't, his forecast busts as well.

------------------

Again, though, from my observation, the largest factor in whether a specific area experiences full hurricane conditions in every given year is the factor of pure CHANCE. All other factors pale in comparison; but can be fun to study and one can come up with this percentage or that.

And concerning Lushine's conclusions: I would simply assume that when May is dry in S. Florida, S. Florida is more likely to see a hurricane the coming season, than is those years that May is wet. But, since S. Florida "only" sees a hurricane once every 7 years (or so), it is the "chance" factor that weighs more heavily, and most heavily.

Nice post. This has interested me and I decided to do some research on it. Lushine is no hack like you pointed out and he does say there is no guarantee on his theory. He states that a dry May has South Florida 3 times more likely for a hurricane strike and a wet May 3 times less likely for a hit. He looks at 75 years of May rainfall data for South Florida. Doing a quick look at some South Florida rainfall data I can see how one could come up this theory. It''s an interesting theory.

[Ed Lizard]

12Z Euro sort of resembles the 12Z GFS right down to the broad area of low pressure calving off lows that get carried Northeast away from the Caribbean.

Don't watch the JB videos anymore, but this doesn't seem to be the way to "bundle the energy" (JB phrase) into any kind of storm.

[flwxwatcher45]

12Z Euro sort of resembles the 12Z GFS right down to the broad area of low pressure calving off lows that get carried Northeast away from the Caribbean.

Don't watch the JB videos anymore, but this doesn't seem to be the way to "bundle the energy" (JB phrase) into any kind of storm.

Speaking of J.B videos, I did watch his video today( the pay site doesn't start until June 1 now) He thinks the GFS is out to lunch sending the energy NE and he seems to think that the system down in the Caribbean will head toward the Gulf.

[wxmeddler]

Speaking of J.B videos, I did watch his video today( the pay site doesn't start until June 1 now) He thinks the GFS is out to lunch sending the energy NE and he seems to think that the system down in the Caribbean will head toward the Gulf.

is this based on some evidence ( digging trough. etc.) or is it just joe that is now off a leash.

[downeastnc]

Me and Shaggy looked into years with high numbers of tornados in NC and the following tropical seasons. We have only done it for storms since 1950 as the info on tornado numbers is less than stellar before then.

Here is the thread and this is all just a quickie look up but the basic's look solid. So far this year NC has had well over 30 tornados, all but 1 of the 6 years we found since 1950 with 30 or more tornados had landfalling TC in North Carolina the only year that had 30 tornados and didnt have a TC was 2009 which was terrible overall for tropical systems. In years we have had less than 10 tornados by June 1st we have had 0 landfalling TC so take it for whats it worth.

http://www.americanw...and-hurricanes/

[MJW155]

I personally have not done a statistical study on this matter, so I don't know what holds true more often: what Jim Lushine noted, or what you have noted.

I do know that Lushine's reputation at the NHC for decades was of the highest order. Although his formal position was in the NWS side of the office, he contributed often to the NHC's reasoning when forecasting, and was considered by most to be one of the most knowledged meteorologists (tropical and otherwise) at the office. He eventually became head of the NWS in Miami.

Now, that doesn't mean his study of May rainfall in S. Florida vs. the coming season's hurricane strikes is "correct"; but it does lead one to assume that he used valid data to come to his conclusion. Are you suggesting or simply assuming he made the data up?

I can only guess that his criteria for calling May a "dry" month might be different than yours (your office). Maybe he only used the very driest of Mays in drawing his conclusion; and some of those years that you (your office) called May "dry" are not included. OR vice-versa.

As a frame of reference:

I do notice in your statement the word "STRONG" correlation: does that mean you found a not so strong correlation? Most, if not all, long term (season long) meteorological correlations do not exceed 60%. If a study comes up with any seasonal forecast correlation over 60%, one has to be extremely suspicious of the study.

---------

My guess, when I first read about Lushine's conclusions in the Miami Herald, was that the cause of the correlation he came to was the idea that in those years that deep easterlies set up early in the "summer" season, they are more likely to be more prevalent during the upcoming months. Hence, when the few hurricanes each year got into "possible striking trajectory" towards S. Florida, the probability of deep easterlies extending past 80 degrees W. at those times were greater than in years when the deep easterlies did not set up so early, or at all.

A correlation/forecast based on persistence. And, as we all know, even Bill Gray's parameters are almost all (if not all) based on certain factors persisting. When they don't, his forecast busts as well.

------------------

Again, though, from my observation, the largest factor in whether a specific area experiences full hurricane conditions in every given year is the factor of pure CHANCE. All other factors pale in comparison; but can be fun to study and one can come up with this percentage or that.

And concerning Lushine's conclusions: I would simply assume that when May is dry in S. Florida, S. Florida is more likely to see a hurricane the coming season, than is those years that May is wet. But, since S. Florida "only" sees a hurricane once every 7 years (or so), it is the "chance" factor that weighs more heavily, and most heavily.

I didn't note anything. I just asked on Miami's facebook page if it was true.

[rainstorm]

http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?time=2011052712&field=Sea+Level+Pressure&hour=168hr

with the high over greenland and that trough over se canada/ne US. this will have a real hard time to develop.

[Srain]

I'd take it with a 'grain of salt', but interesting none the less...

http://www.nhc.noaa....forecasts.shtml

[flwxwatcher45]

I'd take it with a 'grain of salt', but interesting none the less...

http://www.nhc.noaa....forecasts.shtml

Someone needs to tell them it's May, not April..

[am19psu]

I'd take it with a 'grain of salt', but interesting none the less...

That low is almost certainly going to form. But it's not modeled to have much central convection nor a tight a core. Things can change, but it looks like it will be a lot of disorganized garbage at this time.

[Eyewall2005]

If anything forms across the caribbean it will be some half-baked STC/TC that will be sheared from the sw & w and battle dry air entrainment from the west. Can't rule out a 35-40 kt TS, but conditions won't be favorable for much more than that...if it forms at all. This system will be induced by the right-rear quad of a mod/stg anticyclonically curved upper-level jet, and the RR quad is the most divergent portion of the jet max, and that will act to drop sfc pressures across the western Carib Sea. HOWEVER...those 35-50 kt swly 200 mb winds will create very unfavorable/hostile wind shear conditions that will prevent significant TC development from occurring.

[metalicwx366]

It comes from the caribbean then travels north and strengthens to 994mbs. Is that tropical or not?

[Amped]

I'd take it with a 'grain of salt', but interesting none the less...

http://www.nhc.noaa....forecasts.shtml

A nice low shear region, However there is a strong Tutt to the Northwest of the storm that may pose problems, or not.

[rainstorm]

DT has issued his summer/cane cast.

http://www.wxrisk.com/2011/05/summer-2011-forecast

[Srain]

NATL or EPAC development...or both...

[dtk]

It comes from the caribbean then travels north and strengthens to 994mbs. Is that tropical or not

Neither, it's fiction.

[Srain]

Virtually all the models are in good agreement that a low pressure will form in the SW Caribbean over the next day or two. There is a semi permanent low we often see in Tropical Season in that area. Thunderstorms are firing, but shear remains rather stout across the Yucatan/Cuba, so any development should be slow to occur, if at all. That said, MIMIC does suggest a fold/roll heading into the SW Caribbean, so it is not out of the question that we could see 93L in the next day or so...

[Ed Lizard]

4 maps of the GFS well beyond the resolution reduction takes up a lot of space.

Just saying.

GFS and Euro both show 500-700 mb RH/700 mb RH below 70%, using the PSU e-Wall, anything that does develop I suspect will be half a storm with dry air sharply limiting convection on the Western side.

Buts its May, looking forward to the beginning of June, and glass half full type optimist I am, anything we can discuss in this forum, as we approach 50 pages, is good, a 93L will be a good way to welcome Josh's Part 2 to the 2011 Atlantic threads.

[bronxx]

Nice post. This has interested me and I decided to do some research on it. Lushine is no hack like you pointed out and he does say there is no guarantee on his theory. He states that a dry May has South Florida 3 times more likely for a hurricane strike and a wet May 3 times less likely for a hit. He looks at 75 years of May rainfall data for South Florida. Doing a quick look at some South Florida rainfall data I can see how one could come up this theory. It''s an interesting theory.

For what it's worth, below are rainfall statistics for this May, so far, in Miami, FTL, and West Palm: Miami has recorded 46% of normal, Ft. Lauderdale 4% of normal, and West Palm 21% of normal. And as all three of us concluded (you, me, Lushine) this means, statistically (based on this statistic only) that S. Florida is more likely to see a hurricane this year than in those years that May was wet. Unless these stations get a 3-5 inch thunderstorm before May 31st.

Miami International, Florida (KMIA)

Weather Almanac for May 28, 2011 "

Month-to-date precip. (recorded / normal ) 2.11 " 4.55 " --

Fort Lauderdale-Hollywood International, Florida (KFLL)

Weather Almanac for May 28, 2011

Month-to-date precip. (recorded / normal ) 0.23 " 5.22 " --

Palm Beach International, Florida (KPBI)

Weather Almanac for May 28, 2011

Month-to-date precip. (recorded / normal ) 0.95 " 4.51 "

[phil882]

A lot of convection in the Caribbean right now, but the shear is still a bit too high is promote any sort of development.

The shear gradient is pretty strong right now. GFS is showing the shear slowly lessening over the southern Caribbean, but it still looks like the NW Caribbean (where a lot of these models are showing whatever forms heading) will remain quite hostile due to the TUTT as many of you have alluded to. I think the best case senerio for development would be the system to remain in the southern Caribbean for the next 3-4 days, and then drift northward. That the solution currently suggested by the ECMWF. At this point, it looks rather unlikely that the steering currents will favor anything heading towards the US.