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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2040. Grothar
Quoting 2036. Orcasystems:


I don't know.. I'm not that old..we would have to ask RTLSNK


:) He would know.
Member Since: July 17, 2009 Posts: 69 Comments: 25369
2039. yoboi
Quoting 1998. Tribucanes:


I love your attitude, sounds fair and kind. Yoboi has been asking the same questions for over a year. The same ones over and over and over. He has been answered by many many very very thoroughly. He takes the critic standpoint, refuses to actually seek, but instead comes back the next day and ask the same exact questions with the same exact criticism of the science. He gives cynical responses and can't or won't give up on his denial stances. If you've been asking the same questions for over a year and have been given the science in finite detail, it's not that you can't get it; it's that you refuse to.



I am sorry that I am not an expert with climate change like you.......I am actually trying to learn.....forgive me.... I did not know asking questions was a bad thing......If it makes you feel better....keeping talking down to me......if you keep trying to push me into a fight or flight response I will not take the flight response........
Member Since: Posts: Comments:
Quoting 2034. Grothar:


I don't know, I had to postpone it. They'll let me know sooner or later.
I'm a procrastinator and putting off my funeral too.
Member Since: August 2, 2011 Posts: 0 Comments: 1773
Member Since: Posts: Comments:
Quoting 2033. Grothar:


Is that Steve McQueen running out of the diner?


I don't know.. I'm not that old..we would have to ask RTLSNK
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2034. Grothar
Quoting 2031. unknowncomic:
I assume your doctor said you are going to live.


I don't know, I had to postpone it. They'll let me know sooner or later.
Member Since: July 17, 2009 Posts: 69 Comments: 25369
2033. Grothar
Quoting 2028. Orcasystems:


In the long range Models... Pottery is going to get his. It shows multiples over his house.



Is that Steve McQueen running out of the diner?
Member Since: July 17, 2009 Posts: 69 Comments: 25369
Quoting 2014. Doppler22:

Is it a nice place to go (Natural Bridge)? This is the first time i've heard of it :p


Yup
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Quoting 2026. Grothar:


I bet you even whistle when you wake up in the morning. GRRRRRR.
I assume your doctor said you are going to live.
Member Since: August 2, 2011 Posts: 0 Comments: 1773
Henriette is falling apart as it lost most of the thunderstorm activity.

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2029. Grothar
Quoting 2018. clwstmchasr:
Blog is quiet tonight. I don't see anything on the horizon. Models are all over this place.

Wind shear is still screaming in the Caribbean. I thought we might see something by Wed-Fri this week but it looks like a few more days.


Yes, the blog is quiet tonight. I even found myself having a conversation with Mrs. Grothar over dinner. She even remarked, "The tropics must be quiet?
Member Since: July 17, 2009 Posts: 69 Comments: 25369
Quoting 2026. Grothar:


I bet you even whistle when you wake up in the morning. GRRRRRR.


In the long range Models... Pottery is going to get his. It shows multiples over his house.

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Quoting 2023. mitchelace5:


What do you mean it can't come too soon?
To liven up the blog. It will within a couple of weeks.
Low shear over a good chunk of the MDR in 180 hrs. 50 W seems like a likely area for development around that time. SST getting warmer by the day and Kelvin and Mr Mojo making an appearance also.
Member Since: August 2, 2011 Posts: 0 Comments: 1773
2026. Grothar
Quoting 2020. pottery:

Nice showers here most of the day. Gentle and soaking rain.
Thunder to the north.
Glorious sunset.

Life is good.


I bet you even whistle when you wake up in the morning. GRRRRRR.
Member Since: July 17, 2009 Posts: 69 Comments: 25369
So noone follows the W Pacific and can share some knowledge on Utor - intensity, potential threats and damage, how big of a storm might this turn out be...

looks to me like a steadily intensifying hurricane that mighht not stop until right before landfall in Luzon. Manila is infamous for flooding, IMO this could turn out very bad :/

Anyone with knowledge on the subject?
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Quoting 2016. iloveweather15:
I am watching 3 tropical waves


When does that model show that happening?
Member Since: July 27, 2013 Posts: 0 Comments: 501
Quoting 2019. unknowncomic:
Blog is very quiet. A system to track can't come too soon.


What do you mean it can't come too soon?
Member Since: July 27, 2013 Posts: 0 Comments: 501
Quoting 2020. pottery:

Nice showers here most of the day. Gentle and soaking rain.
Thunder to the north.
Glorious sunset.

Life is good.


Wait for it oh mighty BlobMaster :)
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2021. Patrap
Member Since: July 3, 2005 Posts: 421 Comments: 127566
2020. pottery
Quoting Grothar:
Nothing impressive with these waves. I think the season is ..........just getting started.



Big mess moving into the islands.





Nice showers here most of the day. Gentle and soaking rain.
Thunder to the north.
Glorious sunset.

Life is good.
Member Since: October 24, 2005 Posts: 0 Comments: 24033
Blog is very quiet. A system to track can't come too soon.
Member Since: August 2, 2011 Posts: 0 Comments: 1773
Quoting 2013. BaltimoreBrian:
Today's selection of articles about science, climate change, energy and the environment.


Aloha! Flat-topped coral shows up off Oahu coast for first time




Interesting discovery there.
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I am watching 3 tropical waves
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Asheville is a nice little city! Here's the picture of downtown...



The mountains surrounding the city is beautiful as well! This is my view from a hotel SW of Asheville. Picture doesn't do it a justice.

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Quoting 2011. BaltimoreBrian:


Yup. Luray Caverns is worth a visit too :)

Is it a nice place to go (Natural Bridge)? This is the first time i've heard of it :p
Member Since: Posts: Comments:
Today's selection of articles about science, climate change, energy and the environment.

Himalayas to be wetter and warmer over next century

WRAPUP 1-In North Asia, a growing crisis of confidence in nuclear power

Aloha! Flat-topped coral shows up off Oahu coast for first time


Hey! I got the 2013rd comment in 2013 again :) Coincidence?
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121, was devastated all day at work that we lost our storm.

There'll be others, right?
Member Since: August 4, 2007 Posts: 0 Comments: 3174
Quoting 1944. Doppler22:
Darn, the Orioles lost. Oh well. It looks like it'll be a nice few days ahead. I will be visiting the Natural Bridge in Virginia... Any body ever been there?


Yup. Luray Caverns is worth a visit too :)
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http://www.nrlmry.navy.mil/tcdat/tc13/WPAC/11W.UTOR /ir/geo/1km/20130810.2332.mtsat2.x.ir1km.11WUTOR.100kts-948mb-144N-1259E.100pc.jpg

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I know a little off topic but the Amber Alert for Hannah Anderson that was in effect for California and Idaho is over now. Hannah was found safe and her kidnapper was killed.


On a weather note, it looks like there will be great viewing conditions for the meteor shower
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00z Best Track for Utor up to Cat 3. (100kts)

11W UTOR 130811 0000 14.4N 125.9E WPAC 100 948
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2007. Patrap
Member Since: July 3, 2005 Posts: 421 Comments: 127566
2006. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #19
Typhoon Warning
TYPHOON UTOR (T1311)
9:00 AM JST August 11 2013
===================================

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

At 0:00 AM UTC, Typhoon Utor (955 hPa) located at 14.5N 125.9E has 10 minute sustained winds of 80 knots with gusts of 115 knots. The cyclone is reported as moving west northwest at 11 knots.

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

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

Dvorak Intensity: T5.0

Forecast and Intensity
=========================
24 HRS: 16.9N 122.1E - 85 knots (CAT 4/Very Strong Typhoon) Overland Luzon
48 HRS: 19.1N 117.8E - 85 knots (CAT 4/Very Strong Typhoon) South China Sea
72 HRS: 20.9N 113.8E - 85 knots (CAT 4/Very Strong Typhoon) South China Sea
Member Since: Posts: Comments:
Quoting 1994. TropicalAnalystwx13:

8-10-10

Sure sounds familiar.



Sure does.
Member Since: Posts: Comments:
Quoting 1998. Tribucanes:


I love your attitude, sounds fair and kind. Yoboi has been asking the same questions for over a year. The same ones over and over and over. He has been answered by many many very very thoroughly. He takes the critic standpoint, refuses to actually seek, but instead comes back the next day and ask the same exact questions with the same exact criticism of the science. He gives cynical responses and can't or won't give up on his denial stances. If you've been asking the same questions for over a year and have been given the science in finite detail, it's not that you can't get it; it's that you refuse to.


Aaahh. That makes sense. I wasn't looking at it from your point of view. I've often thought that some of you on WU have the patience of Job in explaining AGW. I guess I would be frustrated as well, if I had to repeat myself ad infinitum. If this was 20 or 30 years ago, w/o the proliferation of websites and "news" media that are sleekly packaged, yet loaded with misleading information, I think there would be a whole lot less refusal to grasp the concepts and the reality of the situation.

Sorry to interfere, Trib. I'll stay out of it next time :)
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2003. JLPR2
Quoting 2002. Tropicsweatherpr:


I also see convection to the north that may help the next waves with less dry air.


Even though there is SAL just to its NW there seems to be enough moisture South and East of it to fight it off.

Also, it seems the 500mb and 700mb vorts, which are aligned, are moving along with the convection, those vorts seem strong enough to either pull the 850mb(surface spin) towards it or develop a new one under it.





And well... even if it doesn't manage anything, at least it's something to watch and analyse. XD
Member Since: Posts: Comments:
Quoting 2000. JLPR2:
Not discounting the TW South of the CV islands. Excellent vorticity in the mid levels (500mb and 700mb), surface vort is slightly displaced to the west and weaker, but still there.

It's moving a lot of Atmosphere and has lots of precipitate water with it, it's biggest problem is the lack of convection.





I also see convection to the north that may help the next waves with less dry air.
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Yoboi asks a lot of questions and gets a lot of answers. He then reads through what he's been given and cherry picks what he wants to dispute and call into question. All the while not discussing the truth of what information he's been given, just what he has an issue with. I will give him this, he's usually very polite and respectful though.
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2000. JLPR2
Not discounting the TW South of the CV islands. Excellent vorticity in the mid levels (500mb and 700mb), surface vort is slightly displaced to the west and weaker, but still there.

It's moving a lot of Atmosphere and has lots of precipitate water with it, it's biggest problem is the lack of convection.



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Impressive view of Utor on radar.



Link
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Quoting 1989. LAbonbon:


Tribucanes, while I think your points are valid, I've got to speak up a bit for Yoboi. He's been asking lots of questions, both here, and in Rood's blog, regarding AGW. It's difficult for some people who haven't been trained as a scientist, or in the scientific method and peer review process, to fully grasp first those concepts, and then the sheer magnitude and intricacies that is the problem of AGW. Yoboi doesn't give up, though, and keeps asking his questions. I've got to give credit where it's due, and to me, he's shown tenacity in trying to understand the issues that so many others dismiss as either insurmountable, or worse, as fallacy.


I love your attitude, sounds fair and kind. Yoboi has been asking the same questions for over a year. The same ones over and over and over. He has been answered by many many very very thoroughly. He takes the critic standpoint, refuses to actually seek, but instead comes back the next day and ask the same exact questions with the same exact criticism of the science. He gives cynical responses and can't or won't give up on his denial stances. If you've been asking the same questions for over a year and have been given the science in finite detail, it's not that you can't get it; it's that you refuse to.
Member Since: Posts: Comments:
1997. dipchip
1957: Me Too!! 2.5 inches in my gage today just south of the 1960 bridge on Lake Houston.
Member Since: Posts: Comments:
Quoting 1990. TropicalAnalystwx13:

ESRL's monthly composites possibly?

Daily composites, if so.


Found it


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1995. Patrap
Typhoon 11W UTOR

UW-CIMSS Automated Satellite-Based
Advanced Dvorak Technique (ADT)
Version 8.1.4
Tropical Cyclone Intensity Estimation Algorithm

Current Intensity Analysis



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.4
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 10 AUG 2013 Time : 231500 UTC
Lat : 14:28:18 N Lon : 125:56:20 E


CI# /Pressure/ Vmax
4.4 / 977.7mb/ 74.6kt


Final T# Adj T# Raw T#
4.4 4.4 4.2

Center Temp : -72.0C Cloud Region Temp : -80.3C

Scene Type : EMBEDDED CENTER CLOUD REGION w/ MW EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : MW ON
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 87km
- Environmental MSLP : 1007mb

Satellite Name : MTSAT2
Satellite Viewing Angle : 27.8 degrees



Member Since: July 3, 2005 Posts: 421 Comments: 127566
"The Tropical Atlantic is quiet, and there are no threat areas to discuss today. The Invest 93 system we were tracking has been destroyed by dry air and wind shear. There are a couple of long-range threats suggested by some of the models--the GFS model predicts a tropical depression could form off the coast of Mississippi six days from now, and the NOGAPS model thinks something could get going in the Gulf of Mexico's Bay of Campeche seven days from now. Neither of these possibilities are worthy of concern at present. Overall, it's been a surprisingly quiet August, considering the pre-season predictions of a hyperactive season. According the National Hurricane Center, this hurricane season has been exactly average so far. There have been three named storms and one hurricane as of August 12. The average date of formation of the third named storm is August 13. One hurricane typically forms by August 10. One reason for this year's inactivity may be an unusual number of upper-level low pressure systems that have paraded across the tropical Atlantic. These lows, also called Tropical Upper Tropospheric Trough (TUTT) lows, tend to bring high wind shear that inhibits tropical cyclone formation. The other major factor appears to be that vertical instability has been unusually low in the Atlantic over the past month. Instability is measured as the difference in temperature between the surface and the top of the troposphere (the highest altitude that thunderstorm tops can penetrate to.) If the surface is very warm and the top of the troposphere is cold, an unstable atmosphere results, which helps to enhance thunderstorm updrafts and promote hurricane development. Since SSTs in the Atlantic are at record highs, enhancing instability, something else must be going on. Dry air can act to reduce instability, and it appears that an unusually dry atmosphere over the Atlantic this month is responsible for the lack of instability." - Dr. Masters, 8-10-10

Sure sounds familiar.

This too:

"What is really odd about this year, though, is the lack of tropical cyclone activity across the entire Northern Hemisphere. Usually, if one ocean basin is experiencing a quiet season, one of the other ocean basins is going bonkers. That is not the case this year. Over in the Eastern Pacific, there have been five named storms and two hurricanes. The average is seven named storms and four hurricanes for this point in the season. This year's quiet season is not too surprising, since there is a moderate La Nina event underway, and La Nina conditions usually supresses Eastern Pacific hurricane activity. But over in the Western Pacific, which usually generates more tropical cyclones than any ocean basin on Earth, it has been a near-record quiet season. Just four named storms have occurred in the West Pacific this year, and the average for this date is eleven. Only one typhoon season has had fewer named storms this late in the season--1998, with just three. The total number of named storms in the Northern Hemisphere thus far this year is fifteen, which is the fewest since reliable records began in 1948" - Same person, same date
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1993. vis0
Quoting 1626. washingtonian115:
What if you walk out one day and saw this?.Except for the saying when pigs fly how about when cows fly?.

GATEWAY going mobile?

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Does anyone here follow the Pacific typhoon season and care to shed some light on the potential max intensity and impact of Utor - those IR shots up top look pretty scary, it might be trying to become annular IMO and its definitely intensifying still, Philippines might be in for a bad bad storm :///
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1991. Patrap
This is a good place to understand climate change from NOAA.


www.ncdc.noaa.gov/indicators

How do we know humans are the primary cause of the warming?

A large body of evidence supports the conclusion that human activity is the primary driver of recent warming. This evidence has accumulated over several decades, and from hundreds of studies. The first line of evidence is our basic physical understanding of how greenhouse gases trap heat, how the climate system responds to increases in greenhouse gases, and how other human and natural factors influence climate. The second line of evidence is from indirect estimates of climate changes over the last 1,000 to 2,000 years.

These estimates are often obtained from living things and their remains (like tree rings and corals) which provide a natural archive of climate variations. These indicators show that the recent temperature rise is clearly unusual in at least the last 1,000 years. The third line of evidence is based on comparisons of actual climate with computer models of how we expect climate to behave under certain human influences.

For example, when climate models are run with historical increases in greenhouse gases, they show gradual warming of the Earth and ocean surface, increases in ocean heat content, a rise in global sea level, and general retreat of sea ice and snow cover. These and other aspects of modeled climate change are in agreement with observations.
Member Since: July 3, 2005 Posts: 421 Comments: 127566
Quoting 1988. nrtiwlnvragn:


Don't know, I was going to look at that but can't find that website in my links that you can do the custom analysis of the data. Too many links, forget what the name means on some of them. LOL

ESRL's monthly composites possibly?

Daily composites, if so.
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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.