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Atlantic Tropical Action 2013

HurricaneJosh

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GaWx

GaWx

Posted
Posted

% of TC geneses by MJO phase that were major H’s at strongest (1995-2012 for 6/1-11/30)

 

1: 6 of 27  22%

2: 13 of 44 30%

3: 6 of 20 30%

4: 4 of 24 17%

5: 1 of 19 5%

6: 1 of 14 7%

7: 3 of 6 50%

8: 2 of 12 17%

 

Circle: 30 of 120 25%

 

All: 66 of 286 23%

 

 Note that phases 2 and 3 were pretty impressive with 30% for each (19 of 64 in total) vs. the overall avg. of only 23%. So, in still another way phases 2 and 3 are significant in terms of tropical impact. In stark contrast, look at how low phases 5 and 6 are (only 6-7% from 2 of 33). So, only 2 of 33 majors for phases 5-6 vs. 19 of 64 for phases 2-3!

 

 Phase 7 is interesting with its 50% from 3 of 6. I'd prefer not to put too much emphasis on this since it is based on a small number of TC's (only 6) and the high % of majors seems a bit counterintuitive. Nevertheless, perhaps the real % is, indeed, high. If so, I don't have the reason.

 

  I'll now look at those six TC's from phase 7:

 

1) 10/7/1995's Roxanne: cat. 3 NW Caribbean into Yucatan

2) 9/24/1996's Isidore: cat. 3 MDR into open north Atlantic

3) 11/13/1999's "Wrong Way" Lenny: cat. 4 moved eastward in Caribbean and hit Virgin Islands.

 

4) 8/22/01's TS Dean hit Bermuda

5) 10/12/01's Karen: cat. 1 NW of Bermuda to Nova Scotia

6) 7/16/06's TS #2: did little and was in north Atlantic

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bluewave

bluewave

Posted
Posted

The July SST profile off the East Coast resembles the active period for the East Coast 

back in the 50's during the last +AMO phase. So I think that the EC could see at least

one noteworthy tropical storm or hurricane before the season is over. It's very

difficult to guess what the intensity or exact track may be from this far out.

 

 

 

 

 

 

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AvantHiatus

AvantHiatus

Posted
Posted

I think that period was greatly influenced by the Pacific profile, which in this case is very different

In relation to the 1981-2010 average. Here is the PDO for Jan, Feb, March, April, and May. While it has been running around neutral this year, it is not as warm as the map would imply and may become negative again as we progress into the summer.

 

The conjunction of a 1950's pattern with a warmer 21st century world is probably responsible for events like Hurricane Sandy, as last year the PDO was very negative with a similar warm SST profile.

 

2013** -0.13 -0.43 -0.63 -0.16 0.08

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bluewave

bluewave

Posted
Posted

I think that period was greatly influenced by the Pacific profile, which in this case is very different

 

Yeah,La Nina and -PDO favor active years along the East Coast relative to Ninos and neutrals.

But a stronger Western Atlantic Ridge over the warmer SST's would promote the potential

for landfalls north of JAX. The Atlantic signal trumped the Pacific signal with Isabel

during the +PDO in 2003. So if we actually get a system in the pipeline, the recurvature

could be blocked.

 

 

 

 

 

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bluewave

bluewave

Posted
Posted

In relation to the 1981-2010 average. Here is the PDO for Jan, Feb, March, April, and May. While it has been running around neutral this year, it is not as warm as the map would imply and may become negative again as we progress into the summer.

 

The conjunction of a 1950's pattern with a warmer 21st century world is probably responsible for events like Hurricane Sandy, as last year the PDO was very negative with a similar warm SST profile.

 

True. The previous winter ENSO signal is important in determining how the landfall pattern evolves during the hurricane season.

I ran a rough calculation for TC activity along the EC north of JAX going back to 1950  from the winter ENSO state.

 

Winter Nino 3.4

 

-0.5 or lower.......54%... of hurricane or tropical storm landfall north years of JAX

-0.4 to +0.4........33%....

+0.6 or higher.....13%...

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AvantHiatus

AvantHiatus

Posted
Posted

True. The previous winter ENSO signal is important in determining how the landfall pattern evolves during the hurricane season.

I ran a rough calculation for TC activity along the EC north of JAX going back to 1950  from the winter ENSO state.

 

Winter Nino 3.4

 

-0.5 or lower.......54%... of hurricane or tropical storm landfall north years of JAX

-0.4 to +0.4........33%....

+0.6 or higher.....13%...

Interestingly enough, some famous EC landfall years such as 2003 experienced weak-moderate el nino conditions in the preceding winter. While Irene and Sandy impacted after very cool la nina winters and 2013 winter ENSO would argue for a greater chance of landfalls north of JAX than usual. Hurricane Fran is my analog of choice for this hurricane season for both track and intensity and it follows the ENSO correlation you have posted here.

 

http://en.wikipedia.org/wiki/Hurricane_Fran

 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

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phil882

phil882

Posted
Posted

94L is looking good, has convection around the center and this could be a small tight system with a potential of moderate tropical storm strength so this one could surprise with the fact this is small, if anything it will bring much needed rain to Texas

 

The system over the central Atlantic looks more impressive in my opinion. 94L won't have much of a change to organize thanks to the combo of a large upper level trough over central North America plus the outflow from Erick thats only likely to reinforce this trough. The system in the Central Atlantic has a tough road ahead of it too since although the upper level flow should remain easterly, the TUTT features that are persistant around 20N is weakening the upper level ridge as you move westward into the Atlantic. Thus, increase westerly shear might be an issue for this system beyond 50W, although it wouldn't be impossible to see this system organize into a TC before then (a la Ernesto) 

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wxtrackercody

wxtrackercody

Posted
Posted

 

The system over the central Atlantic looks more impressive in my opinion. 94L won't have much of a change to organize thanks to the combo of a large upper level trough over central North America plus the outflow from Erick thats only likely to reinforce this trough. The system in the Central Atlantic has a tough road ahead of it too since although the upper level flow should remain easterly, the TUTT features that are persistant around 20N is weakening the upper level ridge as you move westward into the Atlantic. Thus, increase westerly shear might be an issue for this system beyond 50W, although it wouldn't be impossible to see this system organize into a TC before then (a la Ernesto) 

 

The upper-level trough is expected to lift northeast while leaving a cut-off upper-level low behind to drift southwestward. This should provide a favorable shear environment across the western Gulf of Mexico by Sunday, but whether the system is inland by that point is yet to be determined. 

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mupawxnut

mupawxnut

Posted
Posted

Interestingly enough, some famous EC landfall years such as 2003 experienced weak-moderate el nino conditions in the preceding winter. While Irene and Sandy impacted after very cool la nina winters and 2013 winter ENSO would argue for a greater chance of landfalls north of JAX than usual. Hurricane Fran is my analog of choice for this hurricane season for both track and intensity and it follows the ENSO correlation you have posted here.

http://en.wikipedia.org/wiki/Hurricane_Fran

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

So are you pretty much saying "look out" to North Carolina?
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AvantHiatus

AvantHiatus

Posted
Posted

So are you pretty much saying "look out" to North Carolina?

Yeah and the southeast coast in general, but don't take it to heart. Predicting the exact intensity and track is impossible even in 2013, at least from this far out. It appears that the era of no major hurricane landfall is ending; if not going solely by statistics it is extremely likely to happen somewhere in the US (but for any given location is rather low chance). Another end of the spectrum also agree that the conditions right now are simply favorable for the Southeast to be impacted.

 

The +NAO combined with changes in the pacific pattern may cause the Bermuda high to close the door on any re-curving tropical cyclones since the mean trough position ends up further northeast instead of along the East Coast as occurred last year.

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Alfoman

Alfoman

Posted
Posted

Hi guys! I usually don't really post on here, but I lurk all day and all night for any new updates. I'm 16 and hoping to be a meteorologist someday, but until then I have you guys to teach me. Please correct me if I'm wrong. My take on the three systems in the Atlantic right now...

 

1) 94L in Gulf: Well this disturbance will not amount to too much besides a possible TD or very weak TS moving int TX/LA sometime sunday or moday. As the south to north flow in the Gulf stays (not conductive for significant tropical development) and the upper level trough thats dominating the central part of North America- not much will be able to come out of this storm. We do have a surface low that has been slowly developing, but there are just too many factors prohibiting development. As of now, it is a pretty disjointed system which means that it's vorticity has become elongated and not concentrated. As the trough departs, a cut off low could develop from the remaining energy but other than that, nothing stronger than 40/45 mph weak TS.

 

2) ULL in the Central Atlantic: This one would have some potential if only it had time! Upper Level Lows have a tough time already trying to work their way down to the surface, but the pressure gradient is to strong north/south of it causing 40 knot shear over the ULL and there is a bunch of dry air surrounding the system. The system should reach Florida in a few days, and it might just work its way down to the surface as it interacts with the tropical wave that's near the Lesser Antilles right now. As the dry air decreases as it moves westward and it reaches warmer waters near the Bahamas, there is a chance that this system could develop. Also, if it reaches the gulf, more could happen as shear lessens up and the SST warm up too.

 

 

3) The Wave off of Africa: This is the most promising feature of the three, and the mostly likely to be 95L. However, it looks good mostly because it is still embedded in the ITCZ. The dry air is still pretty intense north of the system, even though shear will stay at 5-10 knots. The system will have to grow its moisture field as it parts from the ITCZ, gain additional surface lift, and moisten the dry atmosphere around it for it to survive the next few days in the wild Atlantic. It has looked better and better throughout the day though, and it is possible for this system to survive as it near the Lesser Antilles especially cause the Carioles effect will take place (yay!). If it does live, it could easily be our first legitimate threat of the season. 

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GaWx

GaWx

Posted
Posted

 MJOwise, the forecast I just saw has it going into the circle soon. If that verifies, that would make the MJO essentially a neutral factor as being within the circle has been neither enhancing nor detracting to TC genesis chances overall since 1995. If it were to, instead go bodily into phase 2 and stay there a few days, that would make the MJO enhancing to chances. Phase 1, where it is currently, is neutral in a similar way to being within the circle.

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Alfoman

Alfoman

Posted
Posted

 MJOwise, the forecast I just saw has it going into the circle soon. If that verifies, that would make the MJO essentially a neutral factor as being within the circle has been neither enhancing nor detracting to TC genesis chances overall since 1995. If it were to, instead go bodily into phase 2 and stay there a few days, that would make the MJO enhancing to chances. Phase 1, where it is currently, is neutral in a similar way to being within the circle

Ensemble GFS Phase Diagram

post-4330-0-29690600-1373086252_thumb.gi

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phil882

phil882

Posted
Posted

None of these disturbances have more than a low chance to become something but there are always surprises.

A couple more weeks and ill be taking those central Atlantic waves a lot more seriously, especially given a steering pattern that could favor US landfalls.

www.atmos.albany.edu/student/ventrice/real_time/maps/velocity_pot/anom/28.gif

One thing that does lend some support towards early MDR TCG is the +1-2C SSTA in the east Atlantic. Combined with favorable broad upper level VP associated with the MJO, the current wave over the CATL has a better chance than normal for development.

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Superstorm93

Superstorm93

Posted
Posted

EGIN
NHC_ATCF
invest_al952013.invest
FSTDA
R
U
040
010
0000
201307061125
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 95, 2013, DB, O, 2013070606, 9999999999, , , , , , METWATCH, , AL952013
AL, 95, 2013070606, , BEST, 0, 77N, 307W, 25, 0, DB, 0, , 0, 0, 0, 0,

 

 

 

CLOUDINESS AND THUNDERSTORMS CONTINUE TO SHOW SOME SIGNS OF
ORGANIZATION IN ASSOCIATION WITH A TROPICAL WAVE OVER THE FAR
EASTERN ATLANTIC ABOUT 800 MILES SOUTHWEST OF THE CAPE VERDE
ISLANDS. ENVIRONMENTAL CONDITIONS COULD BE BECOME A LITTLE MORE
CONDUCIVE FOR DEVELOPMENT TO OCCUR OVER THE NEXT FEW DAYS WHILE THE
DISTURBANCE MOVES WESTWARD AT 15 TO 20 MPH. THIS SYSTEM HAS A LOW
CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

 

 

 

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GaWx

GaWx

Posted
Posted

Ensemble GFS Phase Diagram

attachicon.gifmjo july 6th.gif

Thanks! Well, MJOwise at least, this is a horse of a different color. With this suggesting a week or so of phase 2, one of the most favorable phases in July and in general as opposed to the not nearly as favorable phase 1 and circle, the MJO is relatively favorable in itself. Since 1995, here are the number of TC's that have formed in July by phase:

1: 3

*2: 8

3: 3

4: 5

5: 0

6: 2

7: 1

8: 2

C: 10

After normalization, phases 2 and 4 followed by 3 have been the most active. Phase 1 has had far fewer geneses than 2-4 after norm. Also, don't be deceived by the 10 in circle as there have been about four times as many C days as phase 2 days since 1995 during the H season. Other than the C, phase 1 has had the most days in H season.

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hurricaneman

hurricaneman

Posted
Posted

95l is the definition of a Tropical Depression, closed circulation, consistent convection over the center, but we cant be sure since there are no observations in that particular area so we have to wait for Dvorak numbers to see whats going on at the surface

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