An Active Atlantic Hurricane Season Still Predicted by NOAA, CSU, and TSR

By: Dr. Jeff Masters , 4:07 PM GMT on August 09, 2013

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As we stand on the cusp of the peak part of hurricane season, all of the major groups that perform long-range seasonal hurricane forecasts are still calling for an active 2013 Atlantic hurricane season. NOAA forecasts an above-normal and possibly very active Atlantic hurricane season in 2013, in their August 8 outlook. They give a 70% chance of an above-normal season, a 25% chance of an near-normal season, and 5% chance of a below-normal season. They predict a 70% chance that there will be 13 - 19 named storms, 6 - 9 hurricanes, and 3 - 5 major hurricanes, with an Accumulated Cyclone Energy (ACE) 120% - 190% of the median. If we take the midpoint of these numbers, NOAA is calling for 16 named storms, 7.5 hurricanes, 4 major hurricanes, and an ACE index 155% of normal. This is well above the 1981 - 2010 average of 12 named storms, 6 hurricanes, and 3 major hurricanes. Hurricane seasons during the active hurricane period 1995 - 2012 have averaged 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index 151% of the median.


Figure 1. Tropical Storm Dorian on July 25, 2013, when the storm reached peak intensity--sustained winds of 60 mph. Formation of early-season tropical storms like Chantal and Dorian in June and July in the deep tropics is usually a harbinger of an active Atlantic hurricane season. Image credit: NASA.

NOAA cites five main reasons to expect an active remainder of hurricane season:

1) Sea Surface Temperatures (SSTs) are above average in the Main Development Region (MDR) for hurricanes, from the coast of Africa to the Caribbean. As of August 9, SST were 0.4°C (0.8°F) above average.
2) Trade winds are weaker than average across the MDR, which has caused the African Monsoon to grow wetter and stronger, the amount of spin over the MDR to increase, and the amount of vertical wind shear to decrease.
3) No El Niño event is present or expected this fall.
4) There have been two early-season tropical storms in the deep tropics (Tropical Storms Chantal and Dorian), which is generally a harbinger of an above-normal season.
5) We are in an active hurricane period that began in 1995.

Colorado State predicts a much above-average hurricane season
A much above-average Atlantic hurricane season is on tap for 2013, according to the seasonal hurricane forecast issued August 2 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 18 named storms, 8 hurricanes, and 3 intense hurricanes, and an Accumulated Cyclone Energy (ACE) of 142. The forecast calls for an above-average chance of a major hurricane hitting the U.S., both along the East Coast (40% chance, 31% chance is average) and the Gulf Coast (40% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also above average, at 53% (42% is average.)

Analogue years
The CSU team picked five previous years when atmospheric and oceanic conditions were similar to what we are seeing this year: cool neutral ENSO conditions and slightly above-average tropical Atlantic sea surface temperatures. Those five years were 2008, a very active year with 16 named storms and 4 major hurricanes--Gustav, Ike, Paloma, and Omar; 2007, an active year with 15 named storms and two Category 5 storms--Dean and Felix; 1996, an above average year with 13 named storms and 6 major hurricanes--Edouard, Hortense, Fran, Bertha, Isidore, and Lili; 1966, an average year with 11 named storms and 3 major hurricanes--Inez, Alma, and Faith; and 1952, a below average year with 7 named storms and 3 major hurricanes. The average activity during these five analogue years was 12.4 named storms, 7.2 hurricanes, and 3.8 major hurricanes.

TSR predicts an above-average hurricane season: 14.8 named storms
The August 6 forecast for the 2013 Atlantic hurricane season made by British private forecasting firm Tropical Storm Risk, Inc. (TSR) calls for an active season with 14.8 named storms, 6.9 hurricanes, 3 intense hurricanes, and an Accumulated Cyclone Energy (ACE) of 121. The long-term averages for the past 63 years are 11 named storms, 6 hurricanes, 3 intense hurricanes, and an ACE of 103. TSR rates their skill level as good for these August forecasts--47% - 59% higher than a "no-skill" forecast made using climatology. TSR predicts a 58% chance that U.S. land falling activity will be above average, a 26% chance it will be near average, and a 16% chance it will be below average. They project that 4 named storms will hit the U.S., with 1.8 of these being hurricanes. The averages from the 1950-2012 climatology are 3.1 named storms and 1.4 hurricanes. They rate their skill at making these August forecasts for U.S. landfalls just 9% - 18% higher than a "no-skill" forecast made using climatology. In the Lesser Antilles Islands of the Caribbean, TSR projects 1.4 named storms, 0.6 of these being hurricanes. Climatology is 1.1 named storms and 0.5 hurricanes.

TSR's two predictors for their statistical model are the forecast July - September trade wind speed over the Caribbean and tropical North Atlantic, and the forecast August - September 2013 sea surface temperatures in the tropical North Atlantic. Their model is calling for warmer than average SSTs and near average trade winds during these periods, and both of these factors should act to increase hurricane and tropical storm activity.


Figure 2. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 1999-2009 (May) and 1998-2009 (August), using the Mean Squared Error. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.


Figure 3. Comparison of the percent improvement in mean square error over climatology for seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 2003-2012, using the Mean Square Skill Score (MSSS). The figure shows the results using two different climatologies: a fixed 50-year (1950 - 1999) climatology, and a 2003 - 2012 climatology. Skill is poor for forecasts issued in December and April, moderate for June forecasts, and good for August forecasts. Image credit: Tropical Storm Risk, Inc.

FSU predicts an above-average hurricane season: 15 named storms
The Florida State University (FSU) Center for Ocean-Atmospheric Prediction Studies (COAPS) issued their fifth annual Atlantic hurricane season forecast on May 30, calling for a 70% probability of 12 - 17 named storms and 5 - 10 hurricanes. The mid-point forecast is for 15 named storms, 8 hurricanes, and an accumulated cyclone energy (ACE) of 135. The scientists use a numerical atmospheric model developed at COAPS to understand seasonal predictability of hurricane activity. The model is one of only a handful of numerical models in the world being used to study seasonal hurricane activity and is different from the statistical methods used by other seasonal hurricane forecasters such as Colorado State, TSR, and PSU (NOAA uses a hybrid statistical-dynamical model technique.) The FSU forecast has been one of the best ones over the past four years:

2009 prediction: 8 named storms, 4 hurricanes. Actual: 9 named storms, 3 hurricanes
2010 prediction: 17 named storms, 10 hurricanes. Actual: 19 named storms, 12 hurricanes
2011 prediction: 17 named storms, 9 hurricanes. Actual: 19 named storms, 7 hurricanes
2012 prediction: 13 named storms, 7 hurricanes. Actual: 19 named storms, 10 hurricanes

Penn State predicts an above-average hurricane season: 16 named storms
A statistical model by Penn State's Michael Mann and alumnus Michael Kozar is calling for an active Atlantic hurricane season with 16 named storms, plus or minus 4 storms. Their prediction was made using statistics of how past hurricane seasons have behaved in response to sea surface temperatures (SSTs), the El Niño/La Niña oscillation, the North Atlantic Oscillation (NAO), and other factors. The statistic model assumes that in 2013 the May 0.87°C above average temperatures in the MDR will persist throughout hurricane season, the El Niño phase will be neutral to slightly warm, and the North Atlantic Oscillation (NAO) will be near average.

The PSU team has been making Atlantic hurricane season forecasts since 2007, and these predictions have done pretty well, except for in 2012, when an expected El Niño did not materialize:

2007 prediction: 15 named storms, Actual: 15
2009 prediction: 12.5, named storms, Actual: 9
2010 prediction: 23 named storms, Actual: 19
2011 prediction: 16 named storms, Actual: 19
2012 prediction: 10.5 named storms, Actual: 19

UK Met Office predicts a slightly above-average hurricane season: 14 named storms
The UKMET office forecast for the 2013 Atlantic hurricane season, issued May 13, calls for slightly above normal activity, with 14 named storms, 9 hurricanes, and an ACE index of 130. In contrast to the statistical models relied upon by CSU, TSR, and NOAA, the UKMET model is done strictly using two dynamical global seasonal prediction systems: the Met Office GloSea5 system and ECMWF system 4. In 2012, the Met Office forecast was for 10 tropical storms and an ACE index of 90. The actual numbers were 19 named storms and an ACE index of 123.


Figure 4. Total 2013 Atlantic hurricane season activity as predicted by twelve different groups.

NOAA predicts a below-average Eastern Pacific hurricane season
NOAA's pre-season prediction for the Eastern Pacific hurricane season, issued on May 23, calls for a below-average season, with 11 - 16 named storms, 5 - 8 hurricanes, 1 - 4 major hurricanes, and an ACE index 60% - 105% of the median. The mid-point of these ranges gives us a forecast for 13.5 named storms, 6.5 hurricanes, and 2.5 major hurricanes, with an ACE index 82% of average. The 1981 - 2010 averages for the Eastern Pacific hurricane season are 15 named storms, 8 hurricanes, and 4 major hurricanes.

NOAA predicts a below-average Central Pacific hurricane season
NOAA's pre-season prediction for the Central Pacific hurricane season, issued on May 22, calls for a below-average season, with 1 - 3 tropical cyclones. An average season has 4 - 5 tropical cyclones, which include tropical depressions, tropical storms, and hurricanes. Hawaii is the primary land area affected by Central Pacific tropical cyclones.

West Pacific typhoon season forecast not available this year
Dr. Johnny Chan of the City University of Hong Kong usually issues a seasonal forecast of typhoon season in the Western Pacific, but did not do so in 2012 or 2013. An average typhoon season has 27 named storms and 17 typhoons. Typhoon seasons immediately following a La Niña year typically see higher levels of activity in the South China Sea, especially between months of May and July. Also, the jet stream tends to dip farther south than usual to the south of Japan, helping steer more tropical cyclones towards Japan and Korea.

Quiet in the Atlantic this weekend
There are no Atlantic threat areas to discuss today, and none of the reliable models for tropical cyclone formation is predicting development during the coming seven days. However, there are some indications that the atmosphere over the tropical Atlantic will become more conducive for tropical storm formation beginning around August 15. The Madden Julian Oscillation (MJO), a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days, may move into the Atlantic then, increasing tropical storm formation odds. At the same time, the computer models are indicating an increase in moisture over the tropical Atlantic, due to a series of tropical waves expected to push off of the coast of Africa. There will also be several eastward-moving Convectively-Coupled Kelvin Waves (CCKWs) traversing the Atlantic during that period. These atmospheric disturbances have a great deal of upward-moving air, which helps strengthen the updrafts of tropical disturbances. Formation of the Eastern Pacific's Hurricane Gil and Henriette were aided by CCKWs. These same CCKWs will cross into the Atlantic and increase the odds of tropical storm formation during the period August 15 - 20.

Have a great weekend, everyone!

Jeff Masters

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Quoting 1086. Gearsts:
Just perfect.

God help Manilla!!
Member Since: July 2, 2013 Posts: 0 Comments: 1521
Quoting 1084. KoritheMan:


That has so much love and liveliness, it almost makes me want to dance.
don`t jinx it.
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1086. Gearsts
Just perfect.
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Quoting 1083. GTstormChaserCaleb:
Good morning.

FIM-7 this one is for you Kori ;)



FIM-9



That has so much love and liveliness, it almost makes me want to dance.
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Good morning.

FIM-7 this one is for you Kori ;)



FIM-9

Member Since: June 30, 2013 Posts: 12 Comments: 8464
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1081. Gearsts
Quoting 1079. MiamiHurricanes09:
Utor up to 70kts (10-minute sustained) as per the JMA.

pinhole eye
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1080. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #13
Typhoon Warning
TYPHOON UTOR (T1311)
15:00 PM JST August 10 2013
===================================

SUBJECT: Category Three Typhoon Named Cyclone In Sea East Of The Philippines

At 6:00 AM UTC, Typhoon Utor (965 hPa) located at 13.9N 129.2E has 10 minute sustained winds of 70 knots with gusts of 100 knots. The cyclone is reported as moving west at 12 knots.

Storm Force Winds
===================
50 NM from the center

Gale Force Winds
==================
120 NM from the center

Dvorak Intensity: T4.5

Forecast and Intensity
=========================
24 HRS: 15.6N 125.6E - 80 knots (CAT 3/Strong Typhoon) Sea East Of The Philippines
48 HRS: 18.0N 122.5E - 85 knots (CAT 4/Very Strong Typhoon) Sea East Of The Philippines
72 HRS: 20.2N 118.3E - 90 knots (CAT 4/Very Strong Typhoon) South China Sea

Additional Information
=======================
Typhoon UTOR will move west for the next 12 hours then move west northwestward

Final initial Dvorak number will be T5.5 after 24 hours
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Down to 45 knots.

EP, 08, 2013081006, , BEST, 0, 144N, 1459W, 45, 1001, TS, 34, NEQ, 50, 20, 30, 50, 1011, 150, 15, 0, 0, E, 0, , 0, 0, HENRIETTE, M,
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Quoting 1071. sar2401:

...The government has never given me anything, but they did extort less from me some years than others.


Yeah, it's good thing all the schools, police, firemen, public utilities, roads, bridges, weather services, emergency services, research agencies, NASA, FDA, etc. were all free!

Seriously, this statement makes you sound like a spoiled over-privileged brat who has absolutely no clue about what it's really like to live in a country where the government truly does nothing for you. Try living in Somalia for a month, or any other third world despotic nation. Good luck tracking hurricanes when you can't even have reliable electricity and internet connectivity, let alone potable water and edible food.
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Ya Sar, I have a big problem with both parties too. Whether one says "saved" or "given" really makes very little difference. I believe either saved/given fits depending on one's slant of the truth. That amount I gave was what the super rich didn't have to pay in taxes. They saved it through the tax cut. AKA they were given it, since they before the cut wouldn't have had it. Democrats/Republicans at the end of the day are one representative party for corporations at the expense of the people. Seasonal outlooks do seem a little pointless Sar, you've convinced me of that. Just too many variables and outlooks.
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1075. TXCWC
can not stay up any longer tonight waiting for model runs...a thing called work tomorrow/this morning...night all
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Well, I'm off for now guys! See you guys when I wake up later. :)
Member Since: July 27, 2013 Posts: 0 Comments: 501
1073. JLPR2
This map should update soon, but nonetheless you can see a decent 850mb vort related to the area firing convection just offshore, SE of the CV islands.

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Quoting 1031. redwagon:
93, I object to your use of 'fantasy' continually. Programming code is incapable of fantasy, but I guess that probably escapes you.


The term "fantasy" in this context is used to describe a very unlikely (if not impossible) outcome. It could also be referred to a nonsense, wishcasting, downcasting, etc. . Programming code is quite capable of fantasy, especially when dealing with chaotic/self-modifying systems. Such systems are inherently unstable and suffer from growing errors over time. Beyond a certain point, any output from said model would indeed be fantasy (a hypercane, sharknado, peace in the middle east, etc.).

If by fantasy you mean creative thinking, then you're statement is also not correct, or at the very least up for debate. There have been a number of relatively recent demonstrations of computers demonstrating creativity in some form or another (including generating original artwork). The problem here is that there really is no objective standard of "creative" or "imaginative". At what point does something become "creative" vs. "formulaic"? It's not an easy question to answer (just look at a movie reviews).




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1071. sar2401
Quoting Tribucanes:
And on the point of the cost of seasonal outlooks; under Bush's tax cuts, the top 1% have been given 708,144,147,723$, the next 4% 326,280,190,858$. While the middle class has been decimated and the bottom growing like a wildfire. Federal spending on NHC's seasonal outlooks a'int the problem. Not to mention under Bush we lost five million jobs while giving our national wealth to the super rich. We lost two million more jobs during Obama's first two years as He turned the sinking ship around and plugged the holes.

Trib, I won't get into a political argument of who's worse, Bush or Obama. Its almost like asking "OK, a panther and leopard both have you trapped. which one would you pick to eat you?". :-) I do find it interesting your choice of words that the groups you noted were "given" money. They were given nothing, they were simply allowed to keep more what they earned. The government has never given me anything, but they did extort less from me some years than others.
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1070. TXCWC
0Z FIM 7 ( 30km 8 and 15km 9 not out yet)

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Quoting 1068. JLPR2:
Finally! One that is actually firing convection after moving into water, not much yet but it is a welcomed change.



Now, let's see if the wave can sustain that convection.
Member Since: July 27, 2013 Posts: 0 Comments: 501
1068. JLPR2
Finally! One that is actually firing convection after moving into water, not much yet but it is a welcomed change.



Quoting 1049. sar2401:

But what is really striking in 2007 and 2008 were small storms over Africa that got big once they hit the water. This year, we have big time convection over West Africa while we have much less convection over the Atlantic. Big storms that look good come off the coast and die. Until we get some more instability in the Atlantic, I don't see a change to that pattern.


We need the suppressing influence of the negative MJO to go away.
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1067. yqt1001
A very likely end to the major TC drought that has occurred since early July (Soulik).

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Quoting 1065. canehater1:
It was nice to see Dr.Postel talking about voticity
coming off African Coast and using graphics to
illustrate it on TW updates today on TWC. He also
showed positive MJO moving into Carib and Atlantic
in 168 hrs. with graphics.


One week till nature hits the on switch for the season.
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It was nice to see Dr.Postel talking about voticity
coming off African Coast and using graphics to
illustrate it on TW updates today on TWC. He also
showed positive MJO moving into Carib and Atlantic
in 168 hrs. with graphics.
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Quoting 1053. TXCWC:
At this time what is important is not where models are taking any potential Gulf system or even the strength forecasted but rather that they still show it

GEM


NAVGEM


GFS (normal resolution)


FIM 0Z model runs should be out in a while




I'm still hoping TX gets it. Those rains would be awesome.
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I'm thinking that since the MJO could shift from the E-Pac to the Atlantic next week, that will likely help to destabilize the atmosphere in the tropics.
Member Since: July 27, 2013 Posts: 0 Comments: 501
Quoting 1058. mitchelace5:


Well, isn't vertical instability suppose to increase mid to late August, going into September? On the map, it looks like there's not much heat over the Atlantic if I'm seeing correctly


That map shows (surprising even to me) that the 30-year climatology for relative humidity values over the Atlantic generally falls to the "dry" side of the spectrum, making all this whining and complaining even more baseless.
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Okay Sar, I always like to play your Devil's advocate; but no I would have to agree, they don't really matter all that much and are highly historically inaccurate.
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Quoting 1057. Tribucanes:
Is that the thirty year average for the for 500mb humidity Kori?


That's the established baseline for climatology, so yes.
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1059. sar2401
Quoting Tribucanes:
Sar you make some interesting points about seasonal outlooks. Often they are not very accurate, but the study of seasonal conditions and likelihood of a busy or slow season will be reached in this study. NHC does an outlook, NHC doesn't call them predictions and goes to great lengths to say there are numerous variables that impact what happens. The study of seasonal conditions and likelihood will be done either way, which is the nature of science; to further knowledge and understanding. The outlook is just a part of the study of the science behind the season. We've come light years in predicting and knowledge of tropical systems in a very short time. Should the NHC study likely seasonal conditions and then not give an outlook? It's all about the study of the science and then passing on likelihoods to the public. It certainly doesn't hurt the public or authorities to know an active to very active season is likely.

Trib, I'm 100% for the continuing study of how to predict hurricanes. What I'm not for is public dissemination of so much of this data. For example, Dr. Maters cites six agencies and companies that are making seasonal forecasts. Their records range for pretty good to barely more than flipping a coin. Who is the public to know which forecast, if any, to put any faith into? If we had a color code for something like green for agencies with better track records and red fr companies with poor track records, at least we'd be providing a sort of "Consumer's Report" version of hurricane forecasts. CSU's forecasts are particularly troubling, since they are now getting into areas like probability of where storms are likely to hit, which we have almost no skill in predicting, to analogue years, which we have zero, and maybe less than zero skill on predicting.

This is kind of like six different forecasts for my house today, with the most conservative saying there's a some chance you may get a thunderstorm, to the most aggressive saying the chances are 70 or 80%, and the chances are 10% higher than normal it will hit my house. Without having any idea which forecast has the better track record, I would be a total loss as to what to believe. I think that's true with hurricane forecasts, which means people will tend to ignore all of them.

I'm no fool, and I realize tat hurricane forecasts are some of the best free publicity that universities like CSU, FSU, PSU, and NCSU are going to get. NOAA and the UK Met Office, being government agencies, are always looking for opportunities to show taxpayer's money is being well spent. The most galling is the free publicity that Tropical Storm Risk, a for-profit British company with one of the worst records of seasonal outlooks gets. Lumping them in with better performing out looks gives them a patina of accuracy they don't deserve.

In my perfect work, the outlook would be issue by NOAA, the official government agency in charge of hurricane prediction. The others can still issue outlooks, but you should have to dig for them, which all us weather geeks will do, but not the general public. I realize this will never happen, but we sure devote a ot of time, electrons, and newsprint o things what the average number of hurricanes is 16, exactly NOAA's prediction, while the biggest outliers are 14 and 18. With numbers that tightly clustered together, does it really matter much anyway?
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Quoting 1055. KoritheMan:


High levels of relative humidity are generally associated with high instability levels.

What do you see on that map as the climatological mean?


Well, isn't vertical instability suppose to increase mid to late August, going into September? On the map, it looks like there's not much heat over the Atlantic if I'm seeing correctly
Member Since: July 27, 2013 Posts: 0 Comments: 501
Is that the thirty year average for the for 500mb humidity Kori?
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Quoting 1055. KoritheMan:


High levels of relative humidity are generally associated with high instability levels.

What do you see on that map as the climatological mean?
Finally!! that means stronger systems like 2010.
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Quoting 1054. mitchelace5:


What does this mean?


High levels of relative humidity are generally associated with high instability levels.

What do you see on that map as the climatological mean?
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Quoting 1051. KoritheMan:
There, I looked up the 500 mb climatological mean value for relative humidity levels from July through September. Look what I unearthed:



So... any takers?


What does this mean?
Member Since: July 27, 2013 Posts: 0 Comments: 501
1053. TXCWC
At this time what is important is not where models are taking any potential Gulf system or even the strength forecasted but rather that they still show it

GEM


NAVGEM


GFS (normal resolution)


FIM 0Z model runs should be out in a while



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And on the point of the cost of seasonal outlooks; under Bush's tax cuts, the top 1% have been given 708,144,147,723$, the next 4% 326,280,190,858$. While the middle class has been decimated and the bottom growing like a wildfire. Federal spending on NHC's seasonal outlooks a'int the problem. Not to mention under Bush we lost five million jobs while giving our national wealth to the super rich. We lost two million more jobs during Obama's first two years as He turned the sinking ship around and plugged the holes.
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There, I looked up the 500 mb climatological mean value for relative humidity levels from July through September. Look what I unearthed:



So... any takers?
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Going to be a pretty wet night for my area as the remains of former Hurricane Gil move into the islands. Moisture will linger until tomorrow.

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1049. sar2401
Quoting JLPR2:
Things change quickly, here are two years that were active but had similar or worse areas of Mid-level dry air out in the ATL.C
So don't let your guard down because some SAL is still hanging around in the CATL.

But what is really striking in 2007 and 2008 were small storms over Africa that got big once they hit the water. This year, we have big time convection over West Africa while we have much less convection over the Atlantic. Big storms that look good come off the coast and die. Until we get some more instability in the Atlantic, I don't see a change to that pattern.
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Sar you make some interesting points about seasonal outlooks. Often they are not very accurate, but the study of seasonal conditions and likelihood of a busy or slow season will be reached in this study. NHC does an outlook, NHC doesn't call them predictions and goes to great lengths to say there are numerous variables that impact what happens. The study of seasonal conditions and likelihood will be done either way, which is the nature of science; to further knowledge and understanding. The outlook is just a part of the study of the science behind the season. We've come light years in predicting and knowledge of tropical systems in a very short time. Should the NHC study likely seasonal conditions and then not give an outlook? It's all about the study of the science and then passing on likelihoods to the public. It certainly doesn't hurt the public or authorities to know an active to very active season is likely.
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Quoting 1045. sar2401:

Hooray! Nice to see that the two and five day probabilities are actually being used to give useful information. This is exactly what I'd expect for systems with a chance to develop - a lower two day but a rising percentage for the five day. Let's hope this spreads to the Atlantic as well.


The NHC's experimental five-day outlook has been in effect for both the eastern Pacific and Atlantic basins since beginning of this month. I think this is neat that they use their new outlook for tropical cyclone formation. I wonder if the CPHC will follow NHC's new outlook in the future.
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Obviously people tend to forget that SAL/dry air seems to be a semipermanent feature across the east and central Atlantic during any given year. Of course, dust outbreaks are typically mitigated by increased soil moisture during the preceding year, but the Sahara is a desert; there are going to be periodic dust outbreaks. Africa sees a very wet monsoon this time of year, which normally comes in the form of tropical waves. The winds associated with these features do cause dust. Also, the Bermuda-Azores ridge is going to fluctuate, and when it gets stronger, so too do the accompanying surface winds, which also helps to blow dust into the Atlantic.

This idea of seeing the Atlantic completely clear this time of year is a fantasy.
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1045. sar2401
Quoting Civicane49:
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
1100 PM PDT FRI AUG 9 2013

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

1. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH AN AREA OF
DISTURBED WEATHER LOCATED ABOUT 1000 MILES SOUTHWEST OF THE
SOUTHERN TIP OF BAJA CALIFORNIA HAS CHANGED LITTLE IN ORGANIZATION
OVER THE PAST FEW HOURS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO
BECOME MORE CONDUCIVE FOR SOME DEVELOPMENT OF THIS SYSTEM OVER THE
NEXT FEW DAYS WHILE IT MOVES WESTWARD AT 10 TO 15 MPH. THIS SYSTEM
HAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AND A HIGH CHANCE...60 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.


2. A TROUGH OF LOW PRESSURE LOCATED ABOUT 1550 MILES EAST-SOUTHEAST OF
THE BIG ISLAND OF HAWAII IS PRODUCING LIMITED SHOWER ACTIVITY.
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE ONLY MARGINALLY
FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM OVER THE NEXT SEVERAL DAYS
AS IT MOVES WESTWARD AT AROUND 10 MPH. THIS SYSTEM HAS A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS...AND A LOW CHANCE...20 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 5 DAYS.


FIVE-DAY FORMATION PROBABILITIES ARE EXPERIMENTAL IN 2013. COMMENTS
ON THE EXPERIMENTAL FORECASTS CAN BE PROVIDED AT...

HTTP://WWW.NWS.NOAA.GOV/SURVEY/NWS-SURVEY.PHP?COD E=ETWO

FORECASTER BRENNAN

Hooray! Nice to see that the two and five day probabilities are actually being used to give useful information. This is exactly what I'd expect for systems with a chance to develop - a lower two day but a rising percentage for the five day. Let's hope this spreads to the Atlantic as well.
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1044. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 174 Comments: 54502
1043. KEEPEROFTHEGATE (Mod)
Utor Long Floater - Visible Imagery Loop
Link
Member Since: July 15, 2006 Posts: 174 Comments: 54502
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
1100 PM PDT FRI AUG 9 2013

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

1. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH AN AREA OF
DISTURBED WEATHER LOCATED ABOUT 1000 MILES SOUTHWEST OF THE
SOUTHERN TIP OF BAJA CALIFORNIA HAS CHANGED LITTLE IN ORGANIZATION
OVER THE PAST FEW HOURS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO
BECOME MORE CONDUCIVE FOR SOME DEVELOPMENT OF THIS SYSTEM OVER THE
NEXT FEW DAYS WHILE IT MOVES WESTWARD AT 10 TO 15 MPH. THIS SYSTEM
HAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AND A HIGH CHANCE...60 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

2. A TROUGH OF LOW PRESSURE LOCATED ABOUT 1550 MILES EAST-SOUTHEAST OF
THE BIG ISLAND OF HAWAII IS PRODUCING LIMITED SHOWER ACTIVITY.
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE ONLY MARGINALLY
FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM OVER THE NEXT SEVERAL DAYS
AS IT MOVES WESTWARD AT AROUND 10 MPH. THIS SYSTEM HAS A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS...AND A LOW CHANCE...20 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

FIVE-DAY FORMATION PROBABILITIES ARE EXPERIMENTAL IN 2013. COMMENTS
ON THE EXPERIMENTAL FORECASTS CAN BE PROVIDED AT...

HTTP://WWW.NWS.NOAA.GOV/SURVEY/NWS-SURVEY.PHP?COD E=ETWO

FORECASTER BRENNAN
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Quoting 1038. CybrTeddy:


Lower anomalies.

What would that mean as far as landfalls?
Member Since: September 2, 2011 Posts: 0 Comments: 1148
Original? Next? What do you mean by 'next'? That would imply you comprehend timelines, which is quite laughable.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.