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Atlantic Tropical Action 2012 - Part II


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One thing that raises an eyebrow is the fact that the 12Z GFS lingers the 500mb vort over the Gulf throughout the next week. The ‘front’ is not as strong today as earlier guidance had suggested, but does bring a pre frontal trough offshore and stalls that boundary. The surface reflection does exit off to the ENE in about 80 hours after remaining stationary S of Grand Isle, Louisiana, but an area of disturbed weather appears to linger several hundred miles S of the Middle Texas Coast if the GFS is correct. Yesterday the GFS suggested the surface reflection would be S of the Florida Panhandle, for what it is worth and only lingered for about 48-60 hours before being shunted off to the ENE. And Adam is correct, these 'rainers' seem to be the theme for Gulf 'home grown' systems this season... ;)

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Cheer up. Recon in the Gulf and a science project for Leslie

NOUS42 KNHC 051436

REPRPD

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1035 AM EDT WED 05 SEPTEMBER 2012

SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)

VALID 06/1100Z TO 07/1100Z SEPTEMBER 2012

TCPOD NUMBER.....12-109

I. ATLANTIC REQUIREMENTS

1. TROPICAL STORM LESLIE

FLIGHT ONE --NASA872--

A. 07/0130Z

B. NASA872 0112A LESLIE SURVEILLANCE AV-6

C. 06/1900Z

D. 26.9N 63.3W

E. 07/0130Z TO 07/1130Z

F. 55,000 TO 65,000 FT

G. IP 30.1N 81.2W OUTFLOW LAYER AXIS CYCLONIC S TO N

2. SUSPECT AREA (GULF OF MEXICO)

FLIGHT ONE --TEAL 71--

A. 06/1800Z D. 28.5N 87.8W

B. AFXXX 01DDA INVEST E. 06/1730Z TO 06/2130Z

C. 06/1700Z F. SFC TO 10,000 FT

3. SUCCEEDING DAY OUTLOOK:

A. BEGIN 12-HRLY FIXES AT 07/1200Z IF SUSPECT AREA DEVELOPS.

B. FIX OF TROPICAL STORM LESLIE AT 07/1800Z NEAR 26.6N 63.2W.

AV-6_1st_Flt_Flight_in_Range_EAFB_in_Background.jpg

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Interesting discussion from the NHC's Facebook page about the Isaac remnants:

There have been quite a few inquiries about whether the name "Isaac" would be given to the area of disturbed weather currently located along the northern coast of the Gulf of Mexico, if it were to develop into a tropical cyclone. The short answer is no, it would get a new name.

Our analysis of the satellite, surface, and lower-tropospheric radiosonde data suggested that the disturbance we're currently following originated within Isaac's broad circulation, but that it had its own surface pressure minimum distinct from Isaac's. This was perhaps most apparent late in the day on Monday, when the residual surface center of Isaac was located over western Kentucky while a second weak low was located over northern Mississippi and Alabama. Isaac's circulation continued to weaken after that and became difficult to track, while the new disturbance moved slowly toward the Gulf coast. So what basically happened here is that a little piece of Isaac broke away and moved south.

OK, now everybody get your lawyer and grammar hats on. The National Weather Service rule that applies here reads: "if the remnant of a tropical cyclone redevelops into a tropical cyclone, it is assigned its original number or name".

Notice the rule says "the" remnant, and not "a" remnant. This means that the storm's primary remnant (and not just any old part of it) has to re-develop in order for the name to be retained. Since the primary remnant of Isaac was still in Kentucky when the new low formed and broke away, the rule dictates that the new low is not entitled to the name Isaac.

This rule actually makes a lot of sense. If a storm died and each of two parts re-developed, we couldn't give the same name to both parts. Only the primary remnant would retain the name, while a lesser remnant or part would get a new name.

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New GFS gets rain as close as SC/SW Louisiana, but nothing for us out of 90L. At day 8, moisture looks to be pooling in the BoC. Looks generally unrelated to 90L except its "seed" might be a bit of 500 mb energy and moisture that splits off of 90L. At day 8, a weak wave at 850 mb is moving into the area of enhanced moisture in the BoC from the Caribbean.

The "seed" below...

563231_401848529870952_364527941_n.jpg

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In the Isaac thread, there was some paper thrown out there about fresh(er) water and it's increased ability vs. salt water to intensify storms....(which this disturbance is meandering about)....anyone want to lay their opinion out there on that??

There is a vapor pressure difference between a pure water and a saturated salt water solution. Water should evaporate faster off of fresh water. Other than that...

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New GFS gets rain as close as SC/SW Louisiana, but nothing for us out of 90L. At day 8, moisture looks to be pooling in the BoC. Looks generally unrelated to 90L except its "seed" might be a bit of 500 mb energy and moisture that splits off of 90L. At day 8, a weak wave at 850 mb is moving into the area of enhanced moisture in the BoC from the Caribbean.

The "seed" below...

So:

Isaac

Isaacson

Isaac III (Trip for short).

Got it.

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It's an El Nino year... so probably the former. We'll probably see something like 2-3 NS's after September 30.

Furthermore, historical records indicate that no major hurricane that struck the U.S. during El Niño formed later than September 13 (Jeanne 2004). As the pattern this year has favored a much weaker ridge and stronger shear than in September 2004, and as El Niño should shut down activity by the first week of October (thus shutting down the late-season W Caribbean systems in FL), I am 99% confident that the chances of a major hurricane hitting the U.S. are practically 0% this year. Development this year has been concentrated outside the deep tropics and the TUTT has been relatively strong around 60-70W, which the models forecast to continue through late September. There are already some signs of a suppressed subtropical jet over the MDR, a classic early Niño indicator. There should be no strong systems forming in the MDR or close to land until at least September 13, and seasonal troughiness, a normal feature by late September but earlier this year, argues against higher landfall threats thereafter. So I say that Josh should probably sleep until next year for juicier landfalls.

As an aside, records since 1851 indicate that 2012, with 13 named systems, has seen the largest number of consecutive systems without a major hurricane forming...and that 2010-2012, so far, is the first known occurrence of at least two consecutive seasons with more than 17 named storms and first such occurrence with no major landfalls in the U.S. resulting. Also, the amount of troughiness/recurves during 2010-2012 is unprecedented in that the persistent summer ridge over the Plains and the dominant Hudson Bay vortex really kept Cape Verde and other development offshore or far to the south of the U.S. The repeating synoptic pattern, the low number of U.S. hurricane landfalls, and the number of TC recurves, even back to 1851, is highly unusual. I am starting to wonder whether a long-term climatic factor is at work and whether we are about to see fewer U.S. hurricanes/majors than would be expected over the remaining 10-15 years of the active Atlantic cycle. Thoughts?

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So I say that Josh should probably sleep until next year for juicier landfalls.

Well, at this point, I'm banking on a sexy October in the EPAC. That could definitely bring some magic.

I am starting to wonder whether a long-term climatic factor is at work and whether we are about to see fewer U.S. hurricanes/majors than would be expected over the remaining 10-15 years of the active Atlantic cycle. Thoughts?

I've been kinda wondering that, too, because things have really gone off a cliff with regard to USA landfalls since 2005. Ike was a significant system, I guess, but regardless, the USA is now pushing the better part of a decade without an intense, red-meat landfall.

Mexico and Central America had sexy action as late as 2007 (Dean, Felix), and Cuba as late as 2008 (Gustav, Ike)... But since then, it's been mostly crap across the board. Karl 2010 was a major landfall in MX, officially, but it barely qualified.

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Well, at this point, I'm banking on a sexy October in the EPAC. That could definitely bring some magic.

I've been kinda wondering that, too, because things have really gone off a cliff with regard to USA landfalls since 2005. Ike was a significant system, I guess, but regardless, the USA is now pushing the better part of a decade without an intense, red-meat landfall.

Mexico and Central America had sexy action as late as 2007 (Dean, Felix), and Cuba as late as 2008 (Gustav, Ike)... But since then, it's been mostly crap across the board.

At first glance, we had a lot of months where the NAO was negative. Not every Aug and Sept had a -NAO, but many did of you go back.

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I am starting to wonder whether a long-term climatic factor is at work and whether we are about to see fewer U.S. hurricanes/majors than would be expected over the remaining 10-15 years of the active Atlantic cycle. Thoughts?

Funny how everyone after '04 and '05 was commenting on an increase in frequency of major cane landfalls and now we're talking a decrease/elimination of them...

This can't last forever though, and the longer the US goes without a major cane landfall, the more susceptible the residents in the path will be to complacency.

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At first glance, we had a lot of months where the NAO was negative. Not every Aug and Sept had a -NAO, but many did of you go back.

So you think that's what's behind this?

Funny how everyone after '04 and '05 was commenting on an increase in frequency of major cane landfalls and now we're talking a decrease/elimination of them...

This can't last forever though, and the longer the US goes without a major cane landfall, the more susceptible the residents in the path will be to complacency.

It can't last forever, but it sure is weird. Even during the mega-lame 1970s and '80s, the USA still managed to get hit by majors in 1970, 1974, 1975, 1979, 1980, 1983, 1985, and 1989.

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Funny how everyone after '04 and '05 was commenting on an increase in frequency of major cane landfalls and now we're talking a decrease/elimination of them...

This can't last forever though, and the longer the US goes without a major cane landfall, the more susceptible the residents in the path will be to complacency.

2008 to this year is quite long a period also, so your overall point stands. But for all practical purposes, you gotta count Ike as a major hurricane level impact. The press and the authorities certainly treated Ike as an impending catastrophic landfall, and Ike did manage to cause $30 billion damage (updated total in the 2010 update to "Deadliest, Costliest.." document). There would have been no discernable difference in impact if Ike had acquired another 5 knots in sustained winds before landfall.

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2008 to this year is quite long a period also, so your overall point stands. But for all practical purposes, you gotta count Ike as a major hurricane level impact. The press and the authorities certainly treated Ike as an impending catastrophic landfall, and Ike did manage to cause $30 billion damage (updated total in the 2010 update to "Deadliest, Costliest.." document). There would have been no discernable difference in impact if Ike had acquired another 5 knots in sustained winds before landfall.

If we're going to include 95-kt landfalls also, since they're almost the same as 100-kt landfalls, then the other no-major-landfall streaks become shorter also-- and so this current no-major streak once again stands out. My point is that we can arbitrarily move the goal posts-- but we have to also move those goal posts back to 1851 in order to accurately compare what's happening now with what's happened historically.

The USA has not had a hurricanes with really powerful winds since 2005.

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If we're going to include 95-kt landfalls also, since they're almost the same as 100-kt landfalls, then the other no-major-landfall streaks become shorter also-- and so this current no-major streak once again stands out.

The USA has not had a hurricanes with really powerful winds since 2005.

Oh, I definitely wasn't trying to suggest the expansion of the major landfall definition. I was just responding to the idea of complacency, and suggesting that 2008 was definitely one of those "big deal years."

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