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

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

Share this Blog
79
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1790 - 1740

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50Blog Index

Quoting 1789. Grothar:
Why is everybody mad at each other? Why are people leaving. Why don't they like people from Florida? And why don't they like the NY Giants?


I think the blog is in the middle of an existential crisis.
Member Since: June 1, 2010 Posts: 4 Comments: 3378
1789. Grothar
Why is everybody mad at each other? Why are people leaving. Why don't they like people from Florida? And why don't they like the NY Giants?
Member Since: Posts: Comments:
This is what we need
Member Since: Posts: Comments:
1787. HadesGodWyvern (Mod)

Southern Hemisphere just not giving it up this year.. 90S..
/em>


Reunion RSMC
Tropical Cyclone Outlook
16:00 PM RET August 10 2013
===============================

An ill-defined circulation exists near 7.5S 90.0E with a slow south southwestward motion. Associated winds are weak (15-20 knots reaching 25 knots far away from the center in the south-western sector due to the gradient effect). mean sea level pressure is estimated at 1007 hPa. Convection is weak to moderate and very disorganized.

Environmental conditions are characterized with a strong easterly to north-easterly shear present to the north of the upper level ridge located near 10S. The low level inflow is good over the trade-winds side but does not exist equatorward. Sea surface temperatures are in the 28-29C over the area.

Within the next 3 days, none of the available deterministic models show some significant deepening of this system on a general south-westward motion. The latest output from the ECMWF ensemble tropical cyclone genesis product shows a 30-40% probability during Sunday-Tuesday... by the time where the system should be close to the upper level ridge.

For the next 72 hours, the potential for the development of a tropical depression is poor
Member Since: Posts: Comments:
1786. nigel20
Utor
Member Since: Posts: Comments:
1785. ricderr
Mmm not my fault you chose to move there.



nor did i ask your permission or blessing....if you have a hard time with responses to your posts...please put me on ignore
Member Since: Posts: Comments:
Quoting 1770. panthan63:
all major forecasters call for a above average hurricane season... but not in Pacific where we have seen one storm after another. i love the way thunderstorms with strong winds are now giving a name, helping to up the 'named storms' number.
based on the preseason, i predict the NY Giants will have a losing season and the Saints will win the superbowl. the last several years have been fairly quiet,especially in Texas. we would welcome a cat 5 if it brought rain. we need a storm like Allison.

preseason... ok this post completely confused me. A cat 5 Texas...pre-season. The Saints win the superbowl because of the preseaon. Well what about the Cowboys then. They're 2-0 and they beat the Fins pretty handly. Fins fan here btw...just comfused by the post.

What has kind of scared me all of a sudden was someone mentioning earlier a non secured gas tank. I just purchased a house down here last March and it has one of those and now it has me thing how to secure that bugger. Whether it should be done to the ground or the house. Here I thought having a gas powered hot water heater and stove would be an advantage. I'm kinda scared of anything above a cat 2 right now. But need to figure out a plan of action asap! This is reason #20 something why I dont wanna be chasing any storms this year. So yes you will probably see me on the doomcaster side of things!
Member Since: Posts: Comments:
Quoting 1775. ricderr:
everything revolves around Florida"


i lived in south florida for 9 years...in that time i was hit by 5 hurricanes and 1 tropical storm.....so yep....there's reason why those that live there feel that way...
Mmm not my fault you chose to move there.You pay the price for living in paradise.You should have known about south Florida's violent climate
Quoting 1780. BahaHurican:
This is not going to happen, u know... You're going to take ur daughter to school, and by the time u come back it'll be a lot busier in the ATL.... At least there's school related stuff to get done the next little while.
I'll be busy with a lot of other things as well.
Member Since: Posts: Comments:
Quoting 1780. BahaHurican:
This is not going to happen, u know... You're going to take ur daughter to school, and by the time u come back it'll be a lot busier in the ATL.... At least there's school related stuff to get done the next little while.


I've already forgotten those days...graduated a couple of years ago and bacheloring it up! (yes I just made up a word)
Member Since: Posts: Comments:
1781. nigel20
I'm amazed at the level of warming that has taken place in the Atlantic over the past week, especially the Caribbean.



Member Since: Posts: Comments:
Quoting 1768. washingtonian115:
I'm going to take this advice.I'm not going to comment much either until a threat comes along.After getting attacked for putting a cow pic on the blog because some people have the mentality that "everything revolves around Florida" and I'm getting board discussing fantasy storms.
This is not going to happen, u know... You're going to take ur daughter to school, and by the time u come back it'll be a lot busier in the ATL.... At least there's school related stuff to get done the next little while.
Member Since: October 25, 2005 Posts: 19 Comments: 22101
Quoting 1777. LargoFl:
wish the ignore function really worked in this blog..it doesn't...well good night everyone..remember if you have clear skies tonight and the next 2 nites..the meteor showers sometimes are awesome...........hope no flying cows tho..nite folks.


Thanks for the reminder about the Perseids. It's cloudy, but I'm going to try!
Member Since: June 26, 2013 Posts: 0 Comments: 1817
1778. VR46L
Good Looking for south Texas

Member Since: Posts: Comments:
1777. LargoFl
wish the ignore function really worked in this blog..it doesn't...well good night everyone..remember if you have clear skies tonight and the next 2 nites..the meteor showers sometimes are awesome...........hope no flying cows tho..nite folks.
Member Since: Posts: Comments:
Quoting 1773. TropicalAnalystwx13:

I'm not sure why it's not marked. Upper-divergence is enhancing convective activity, sure, but it still has the characteristics of a tropical wave.

Hmmm....it does some reasonable that a tropical wave could be there. I mean look at the long gap between the tropical wave in the Gulf of Mexico and tropical wave in the mid-ocean....its seems kinda off that their isn't a tropical wave near the Antilles marked on the map.

Sometimes the NHC TAFB maps seem "lazy" when it comes to marking tropical waves....in some cases taking a day or two to add them after they roll off of Africa. I wish I had another tool besides the TAFB maps to ID tropical waves....
Member Since: Posts: Comments:
1775. ricderr
everything revolves around Florida"


i lived in south florida for 9 years...in that time i was hit by 5 hurricanes and 1 tropical storm.....so yep....there's reason why those that live there feel that way...
Member Since: Posts: Comments:
1774. LargoFl
Member Since: Posts: Comments:
Quoting 1762. NCHurricane2009:


Huh? I don't see a tropical wave marked on 12Z TAFB maps at that location...and plus the NHC 2 PM discussion said something about those thunderstorms being associated with mid to upper-level dynamics (probably divergence of westerly upper jet on south side of retrograding upper vortex in the region)....

"THE
MIDDLE TO UPPER LEVEL DYNAMICS BECOME STRONGER E OF 62W AND ARE
GENERATING SCATTERED SHOWERS AND TSTMS 11N-17N BETWEEN 53W-62W.
MOST OF THE STRONGEST CONVECTION REMAINS DIRECTLY EAST OF SAINT
LUCIA ALONG 14N AT THIS TIME."

I'm not sure why it's not marked. Upper-divergence is enhancing convective activity, sure, but it still has the characteristics of a tropical wave, albeit weak for now.
Member Since: Posts: Comments:
1772. nigel20
Latest Southern Oscillation Index values

SOI values for 10 Aug 2013

Average for last 30 days 6.3
Average for last 90 days 8.9
Daily contribution to SOI calculation 17.6

Monthly average SOI values
May 8.0
June 10.6
July 7.4
Member Since: Posts: Comments:
1771. Skyepony (Mod)
Southern Hemisphere just not giving it up this year.. 90S..

Member Since: Posts: Comments:
all major forecasters call for a above average hurricane season... but not in Pacific where we have seen one storm after another. i love the way thunderstorms with strong winds are now giving a name, helping to up the 'named storms' number.
based on the preseason, i predict the NY Giants will have a losing season and the Saints will win the superbowl. the last several years have been fairly quiet,especially in Texas. we would welcome a cat 5 if it brought rain. we need a storm like Allison.
Member Since: Posts: Comments:
1769. nigel20
Quoting 1764. wunderkidcayman:

hopefully not too long our radar is back online and fully operational from a while now

Link

Yeah, our radar has a range of 480km and a coverage area of 960km. It would be a great tool to have during the peak of the hurricane season.
Member Since: Posts: Comments:
Quoting 1765. opal92nwf:
Sitting here watching old TWC 2004 hurricane season coverage on my TV with youtube. All the nostalgia came back watching it. It was amazing how they were covering hurricane Charley and then they were like "Oh and we now have hurricane Ivan in the Atlantic." 2004 was one heck of a year for hurricanes.

Okay, I am realizing that since nothing is going on (basically) right now, I am sort of wasting my time commenting so much on this blog. (not saying you are wasting your time, but I just need a break)

So, I will not be commenting here until the next storm arises.

Hope to see you all again when Erin shows her face!

Good bye for now!
I'm going to take this advice.I'm not going to comment much either until a threat comes along.After getting attacked for putting a cow pic on the blog because some people have the mentality that "everything revolves around Florida" and I'm getting board discussing fantasy storms.
Member Since: Posts: Comments:
Quoting 1763. fireflymom:
We did make use of those after Ike roared through here, they came in hany along with a wind up portable radio.



My son went out and pulled off the solar caps on our fence and brought them in, lining them up on the floor for a path to the bathroom. *G*
Member Since: Posts: Comments:
1766. ricderr
I have more faith in the TS right now....


i have no faith in either this far out
Member Since: Posts: Comments:
Sitting here watching old TWC 2004 hurricane season coverage on my TV with youtube. All the nostalgia came back watching it. What amazed me with that year is how when they were covering a storm like Charley and then they were like "Oh and we now have hurricane Ivan in the Atlantic." 2004 was one heck of a year.

Okay, I am realizing that since nothing is going on (basically) right now, I am sort of wasting my time commenting so much on this blog. (not saying you are wasting your time, but I just need a break)

So, I will not be commenting here until the next storm arises.

Hope to see you all again when Erin shows her face!

Good bye for now!
Member Since: Posts: Comments:
Quoting 1759. nigel20:
Good afternoon fellow bloggers! It has been generally wet along the south and west coast of Jamaica today.



The first image is a software patch of our radar...I'm not sure when our radar will be fully functional.

hopefully not too long our radar is back online and fully operational from a while now

Link
Member Since: Posts: Comments:
We did make use of those after Ike roared through here, they came in hany along with a wind up portable radio.
Quoting 1760. Skyepony:


Those solar lights for staking around your garden like this one..most those you can pull the stake tip out. The bottoms are the size of candles. They fit in candleholders like those ones with a mirror behind them that hang on your wall. I have candle holders that hang on my walls in outbuildings for them.

Member Since: Posts: Comments:
Quoting 1748. TropicalAnalystwx13:

Nah, it comes from the tropical wave currently passing through the Leeward Islands:




Huh? I don't see a tropical wave marked on 12Z TAFB maps at that location...and plus the NHC 2 PM discussion said something about those thunderstorms being associated with mid to upper-level dynamics (probably divergence of westerly upper jet on south side of retrograding upper vortex in the region)....

"THE
MIDDLE TO UPPER LEVEL DYNAMICS BECOME STRONGER E OF 62W AND ARE
GENERATING SCATTERED SHOWERS AND TSTMS 11N-17N BETWEEN 53W-62W.
MOST OF THE STRONGEST CONVECTION REMAINS DIRECTLY EAST OF SAINT
LUCIA ALONG 14N AT THIS TIME."
Member Since: Posts: Comments:
Am from PBC but currently reside in Orlando and it's way hotter up here.
Member Since: Posts: Comments:
1760. Skyepony (Mod)
Quoting 1726. stpetefla:
A fantastic idea that I read somewhere (maybe here?) is to have those solar lights that you use to light walkways outside. It's not enough light to read by, but bright enough to navigate through your house (kind of like a nightlight). Just stick them outside during the day to use at night.


Those solar lights for staking around your garden like this one..most those you can pull the stake tip out. The bottoms are the size of candles. They fit in candleholders like those ones with a mirror behind them that hang on your wall. I have candle holders that hang on my walls in outbuildings for them.
Member Since: Posts: Comments:
1759. nigel20
Good afternoon fellow bloggers! It has been generally wet along the south and west coast of Jamaica today.



The first image is a software patch of our radar...I'm not sure when our radar will be fully functional.
Member Since: Posts: Comments:
Quoting 1756. PalmBeachWeather:
Over rated Taylor Swift.....I don't see the fascination
I'm not a fan of Taylor nor do I really like her.The point of the post was that it was Korithman approved :).
Member Since: Posts: Comments:
Quoting 1716. Bluestorm5:
Yeah, my parents been preparing for a month now too. Mom is having hard time accepting I'm going to be 5 hours away.
That's still close enough for her to "drop in" on your Saturday evening plans... lol
Member Since: October 25, 2005 Posts: 19 Comments: 22101
Quoting 1752. washingtonian115:
Over rated Taylor Swift.....I don't see the fascination
Member Since: Posts: Comments:
Quoting 1744. Gearsts:
The mjo has been mostly in the Southern hemisphere and he said that he didn't know why.


That's not the MJO..
Member Since: Posts: Comments:
Good afternoon, weathergeeks! ;)

Quoting 1622. pottery:

Really, I have no doubt about that.
But not in August, and not as many as predicted.


Pottery, you may be partially right about August, but I'm still reasoning an above average active season for several reasons which Cyberteddy related demonstrably well earlier this morning. But, these are my thoughts based on the simple logic of the moisture-enhancing MJO. The general rule of thumb is when one basin is active the other is more likely to be inactive. Right now we've got systems in the Pacific but none in the Atlantic which would seem to support that theorem, and support the relationship between the MJO and tropical activity no matter which basin. However, the MJO is propagating eastwards now. Shown here in blue(positive pulse):



IMO, the MJO forecast graphic below indicates a weak upward pulse as it enters the Atlantic basin supporting your theory of low activity in August. But, further into the month as it progresses eastwards, the pulse becomes more amplified as it moves eastwards across the MDR, and stronger even as it nears the African coast. So, it may actually be late August before we see any real uptick in activity.



However, what catches my attention in the last MJO graphic is the delayed but continued propagation forecast late in the month in the eastern Pacific which shows a much stronger ascending pulse as we head into September. That could indicate a substantial uptick or even a ramp-up in activity towards the heart of the season.

In the next couple of weeks I think we'll see limited activity with a few homegrown systems spinning up in the GoM and Caribbean, then followed by a brief lull, and then, as the delayed, stronger upward pulse enters the basin in September, we could see prime moisture conditions for development again in the GoM and Caribbean, and as the strong pulse moves further eastwards, interaction with the African twaves should heat up as we approach the very heart of the season in mid-September.

Of course, even the MJO models can hardly be reliable that far out. However, if that verifies, and upper level conditions are favorable as the pulse moves eastwards, that may lend credence to the forecast above average active season.

It would be interesting to know if there's any data supporting the relationship of any CONUS troughing to the MJO when it's in the basin. Earlier, Skye mentioned the MJO's upward pulse in the basin might make for more intense troughing and also spawning the cut-off lows for spinning up at the tail of the troughs. That makes perfect sense, imo. The MJO may also possibly elongate the troughs and even affect their location and shape. And, as Skye also noted, considering our cooler CONUS temperatures this season, this may be a signal of more troughing to come yet.

Until now, I've been quite curiously concerned that the B/A High would funnel CV systems into the Caribbean and GoM, and it still may, but much is going to depend on the strength of the MJO pulse as it propagates eastwards over the next month. Of course, storm tracks will also depend on the strength of any maturing system and its latitudinal position in relationship to the timing of any troughs.

We will see soon enough. ;)
Member Since: Posts: Comments:
Quoting 1749. PalmBeachWeather:
I have a solar powered hula dancer on the dashboard of my Jeep...I bought it at the Dollar Store for $1.00.. She has not stopped dancing for 5 months...I'm all for solar power..and Bud Light
My friends all call her Jasmine
Member Since: Posts: Comments:
Quoting 1730. KoritheMan:


OMG OMG OMG
Member Since: Posts: Comments:
18z NAM - 84 hours end of run. Looks to be a system forming in the Southern Caribbean.
Member Since: Posts: Comments:
Quoting 1746. VR46L:





So is the surface Map wrong with where the TW is marked ?

12Z Surface Map


I stand corrected....I hadn't check the TAFB surface maps for a bit now and was thinking the tropical wave was further southeast of that location. Still though...a tropical wave below an upper vortex usually doesn't develop...
Member Since: Posts: Comments:
Quoting 1747. BahaHurican:
Unless of course you have no rain for months.... of course then the hurricane comes along and blows away your water collection system... gutters, shingles, and roof entire... lol

Solar powered generator????

I have a solar powered hula dancer on the dashboard of my Jeep...I bought it at the Dollar Store for $1.00.. She has not stopped dancing for 5 months...I'm all for solar power..and Bud Light
Member Since: Posts: Comments:
Quoting 1742. NCHurricane2009:

CMC also shows something in the Gulf in about 150 to 180 hrs if you haven't checked it out yet. I am guessing these models are eventuallt developing the tropical wave currently midway between the Lesser Antilles and Cape Verde Islands...

Nah, it comes from the tropical wave currently passing through the Leeward Islands:


Member Since: Posts: Comments:
Quoting 1692. CaicosRetiredSailor:


...the ultimate water storage system

is a cistern
(or in my case, two cisterns)

: )

Unless of course you have no rain for months.... of course then the hurricane comes along and blows away your water collection system... gutters, shingles, and roof entire... lol

Solar powered generator????

Member Since: October 25, 2005 Posts: 19 Comments: 22101
1746. VR46L


Quoting 1736. NCHurricane2009:

The central Gulf swirl is an upper-level vortex not a surface feature...definitely looks cool but not something that would be developing into a tropical entity.

Western Gulf feature is a surface low pressure area supported by divergence caused by the split nature of the upper flow west of the upper vortex. As the upper vortex continues orbiting westward around the southern US upper ridge...so will the split upper flow and so will the surface low pressure area (thus this area will just be crashing into Mexico with no time to develop).

Eastern Gulf stuff is some loose thunderstorm clusters supported by upper divergence east of the upper vortex and maybe surface convergence of a tropical wave passing by to the south....
Quoting 1737. Sfloridacat5:


Upper level feature that enhanced the rainfall over the west coast of Fl. yesterday.
It could need to stay over water (warm water) for a while to work it self down to the surface. Most models don't develop it.



So is the surface Map wrong with where the TW is marked ?

12Z Surface Map

Member Since: Posts: Comments:
1745. Siker
Quoting 1738. Gearsts:
Nothing will develop...

Of course not, the Euro doesn't show it! /s
Member Since: Posts: Comments:
1744. Gearsts
Quoting 1735. Tropicsweatherpr:


This is a good question for Levi to answer as in his past tidbits he has mentioned that the Atlantic would have the most upward motion than the rest of the basins.
The mjo has been mostly in the Southern hemisphere and he said that he didn't know why.
Member Since: Posts: Comments:
Quoting 1728. BahaHurican:
Advice on gas stoves: Secure the gas tank indoors during the duration of the storm i.e. NOT standing freely outdoors, NOT connected to the stove. Depending on the wind velocities, the tank could get gone or cause other problems.


I was actually referring to people that have gas through a gas company, w/o use of a gas tank. If the gas meter gets damaged, no gas. So if they're relying on that to cook w/, they're out of luck. I may have misunderstood his original post - not sure what type of gas he was talking about now. Your point is a good one, though.
Member Since: June 26, 2013 Posts: 0 Comments: 1817
Quoting 1730. KoritheMan:


OMG OMG OMG

CMC also shows something in the Gulf in about 150 to 180 hrs if you haven't checked it out yet. I am guessing these models are eventuallt developing the tropical wave currently midway between the Lesser Antilles and Cape Verde Islands...
Member Since: Posts: Comments:


P20L is going to run into this dry air. One forecast had it dying in 96 hrs., another at 128 hrs.
Member Since: Posts: Comments:
18z NAM
Caribbean ripe for development.
Member Since: Posts: Comments:

Viewing: 1790 - 1740

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Mostly Cloudy
82 °F
Mostly Cloudy