Thoughts on 2013 Atlantic Hurricane Season

[vbhoutex]

The following was part of Larry Cosgrove's latest WeatherAmerica article. He has given me permission to post it here. It speaks to some of the discussions above.

Another topic of conversation has been the ongoing lack of (organized) activity in the tropical regions of both the Atlantic Basin and the Central/Eastern Pacific Ocean theaters. There have been waves and some stronger disturbances, but only two hurricanes with no well-defined threats imminent through the first week of October. It would appear that the "Cape Verde" portion of the tropical cyclone season is done, as the westerlies are descending in latitude and TUTT signatures continue to take shape over the Gulf Stream and central Atlantic Ocean. But I still have concerns that a viable, and possibly persistent, threat remains over the Caribbean Sea, Gulf of Mexico, and the equatorial far eastern Pacific Ocean, where disturbances could "hop" over the Isthmus of Tehuantepec into the Bay of Campeche. With 500MB ridging largely staying over the Florida Peninsula, Bahamas, and Greater Antilles, Texas and the western/central Gulf Coast may still be at risk for a deepening storm over the still warm waters below the Deep South.

It still makes sense to stick with a largely neutral ENSO forecast, much like what is shown by the IRI amalgam released on Friday from sector 3.4. The CFS and ECMWF models, of course, are suggesting something along the lines of a weak "Modoki" El Nino (west-based) and cannot be discounted. If for some reason we see more +PNA ridging and the tropics shut down outside of Central America (both signals pointing toward a positive ENSO episode), then the potential for a colder October and November (and for that matter the winter east of the Continental Divide) must be given very serious consideration.

Prepared by Meteorologist LARRY COSGROVE on
Saturday, September 21, 2013 at 7:40 PM C.T.

disclaimer:
The previous statements are my opinions only, and should not be construed as definitive fact. Links provided on this newsletter are not affiliated with WEATHERAmerica and the publisher is not responsible for content posted or associated with those sites.

Copyright 2013 by Larry Cosgrove
All rights reserved.

[Hammy]

This is unquestionably the weakest season in the entire satellite era.

If the season ended today our ACE count would land us number 2 lowest behind 1983. However, 1983 did have Alicia which is formidable and arguably gave the quality to an otherwise shut down season.

Weakest non-El Nino season in that case.

[tolakram]

Just for reference I found this Atlantic ACE chart on Wikipedia. Something to ponder as we continue to have a remarkably low seasonal ACE.



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

This bar chart is easier to read.



2012 ACE was 133, for reference.

[RainbowAppleJackDash]

I think October will start to get more active, and we'll see an active November (and probs December?) We are about 2 months behind, in terms of climatology (Remember all the March snowstorms here?) Right now the Atlantic feels more like July. But I think we're ready for an active October-November.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Ntxw]

September 24, 2013. The following two images just about sums it up.

[ninel conde]

about as dead as we will ever see it on a sept 24th

[WeatherEmperor]

September 24, 2013. The following two images just about sums it up.

http://i43.tinypic.com/wqsi7r.gif

http://i39.tinypic.com/2h37k0x.gif

Excellent post. When it comes to mother nature, we still have soooo much to learn.

Sent from my HTC EVO 4G LTE

[tolakram]

The drought in SA really shows up on today's global shot.

[ConvergenceZone]

I think October will start to get more active, and we'll see an active November (and probs December?) We are about 2 months behind, in terms of climatology (Remember all the March snowstorms here?) Right now the Atlantic feels more like July. But I think we're ready for an active October-November.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

I doubt it. There's no evidence that points to that. In fact, looking at the Satellite pictures, it seems to clearly going in the opposite direction.

[StarmanHDB]

The drought in SA really shows up on today's global shot.

Where did the ITCZ go? It looks like it barely exists!

[AdamFirst]

I'm calling a wrap on this season. Could see maybe a couple subtropical corpses spin up from the Gulf/Western Caribbean but the clock is weaning quickly. Every storm this year has been a dilapidated, poorly organized corpse.

[ninel conde]

still looks like an early end to the season. 9/2/0 might just do it.

[sunnyday]

What activity? What heart? What season?

[Frank2]

Just my own thoughts but my guess is that the lack of moisture in the world has to do with the loss of forests around the world - you can't get evapotranspiration from cement, and here in South Florida it's been scientifically proven that the urban areas do receive less rainfall than the Everglades.

Years ago it was thought to be only due to convergence fronts, etc., but one CSU meteorologist did write a paper that showed the direct correlation between the loss of Everglades over the past 75 years and a decrease in rainfall along the southeast coast of Florida...

Sad but true - the Earth breathes through open fields and forests and oceans, but when it's "mouth" is covered by cement, less moisture is available for rainfall...

Frank

[HurrMark]

As this season is drawing to a close (there is no reason to think things will pick up a great deal in October), I am believing that El Nino/La Nina or sea surface temperatures are not the biggest factor of whether or not a season will be active - it is atmospheric moisture. It impacts not only the development of thunderstorms, but shear and other parameters that inhibit development. I do not think I can trust another seasonal forecast unless this parameter is seriously factored in.

I really wish there was more data to find out what was going on in 1977 when the combined E-Pac and Atlantic ACE was 47. There was an El Nino but it was not that strong...beyond that, I do not know what other information is out there. I don't know if it means anything but the following winter (77-78) was indeed a doozy...

[blp]

Just my own thoughts but my guess is that the lack of moisture in the world has to do with the loss of forests around the world - you can't get evapotranspiration from cement, and here in South Florida it's been scientifically proven that the urban areas do receive less rainfall than the Everglades.

Years ago it was thought to be only due to convergence fronts, etc., but one CSU meteorologist did write a paper that showed the direct correlation between the loss of Everglades over the past 75 years and a decrease in rainfall along the southeast coast of Florida...

Sad but true - the Earth breathes through open fields and forests and oceans, but when it's "mouth" is covered by cement, less moisture is available for rainfall...

Frank

I know this is off topic for this thread. Can you provide a link to the scientific study you mention above about urban areas versus the Everglades ranfall, because the data I see from the SFWD tells a different story. The Urban areas tend to have more total randfall amounts at least in the last several years. Last year 2012 the Urban areas well exceeded the interior sections. See below and select an entire year:

http://www.sfwmd.gov/portal/page/portal/xweb%20weather/rainfall%20historical%20%28year-to-date%29

[Frank2]

Here's a .pdf slideshow from CSU about the same topic:

http://pielkeclimatesci.files.wordpress ... ppt-21.pdf

I'm trying to think of the research meteorologist who did write the paper, his name is out there in the mist but hopefully it'll come to me...

He was part of the CSU staff involved with the NOAA FACE experienments that ended in 1980, and from what I read about 10 years ago he wrote the paper after that time, so probably during the 1980's...

Wow, his name slips my mind, but perhaps one of the NOAA folks that I worked for at that time might know who I'm referring to - he was already in his early 60s by the early 1980's, slight build with sandy colored hair (he might be passed on by now or in his early 90s), and recall that on his return to Miami in the 1980's he said that his living in Boulder was causing his lips to chap because of the dry climate (not so this summer, that's for sure)...

If it comes to me I'll let all know, though the study shown in the slide show was co-authored by Dr. Pielke, and the meteorologist I'm thinking of might have worked with him on the South Florida rainfall decrease due to urbanization study (they refer to it in the slide show as "land cover", so true), and as the slide show mentions land cover due to several factors has changed greatly over the past 100-300 years. At the time of John Alden, Native Americans once said that a squirrel could go from tree to tree for hundreds and hundres of miles and not touch the ground, and as we know that is no longer is true...

Frank

[psyclone]

Just my own thoughts but my guess is that the lack of moisture in the world has to do with the loss of forests around the world - you can't get evapotranspiration from cement, and here in South Florida it's been scientifically proven that the urban areas do receive less rainfall than the Everglades.

Years ago it was thought to be only due to convergence fronts, etc., but one CSU meteorologist did write a paper that showed the direct correlation between the loss of Everglades over the past 75 years and a decrease in rainfall along the southeast coast of Florida...

Sad but true - the Earth breathes through open fields and forests and oceans, but when it's "mouth" is covered by cement, less moisture is available for rainfall...

Frank

that's an interesting theory and i did view the slideshow linked below too. I recall a theory advanced on the TWC that was just the opposite. they were showing urban heat islands and theorizing that those heat islands helped INCREASE precip as a result of the relative instability related to a local hotspot... it yielded increased convection over, and just downwind of the urban area. i recall satellite pics of thunderstorm activity to demonstrate the phenomenon. On a broader scale, i don't believe deforestation, to the extent that it exists, is in any way responsible for our reduction in TC activity. i would imagine that evapotranspiration is a nominal additive to overall atmospheric water content. afterall, every gallon of water dumped back into the atmosphere via evapotranspiration must have first evaporated from the sea...unless i'm missing something. the sea surface is the proverbial 800lb gorilla. Clearly something is missing this year. i have no idea what that is but something tells me human activity via urbanization/deforestation is not the answer.

[otowntiger]

Just my own thoughts but my guess is that the lack of moisture in the world has to do with the loss of forests around the world - you can't get evapotranspiration from cement, and here in South Florida it's been scientifically proven that the urban areas do receive less rainfall than the Everglades.

Years ago it was thought to be only due to convergence fronts, etc., but one CSU meteorologist did write a paper that showed the direct correlation between the loss of Everglades over the past 75 years and a decrease in rainfall along the southeast coast of Florida...

Sad but true - the Earth breathes through open fields and forests and oceans, but when it's "mouth" is covered by cement, less moisture is available for rainfall...

Frank

I've heard that there are more trees in the U.S. now than 100 years ago. I don't know what the estimates are globally, probably not the same.

[tolakram]

I believe the US has more trees, but places like the Amazon are losing them.

Google project time lapse map. Zoom out to see the overall reduction.

http://earthengine.google.org/#intro/Amazon

I think it's at least worth considering if a great enough loss might alter weather patterns, but I'm not aware (nor have I looked for) any research on this subject.