July 2012: Earth's 4th warmest; update on 94L--a threat to the Antilles

By: Dr. Jeff Masters , 7:19 PM GMT on August 18, 2012

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July 2012 was the globe's 4th warmest July on record, according to the National Oceanic and Atmospheric Administration's National Climatic Data Center (NCDC). NASA rated it the 12th warmest. July 2012 global land temperatures were the 3rd warmest on record, breaking a streak of three months (April, May, and June) when global land temperatures were the warmest on record. July 2012 global ocean temperatures were the 7th warmest on record, and it was the 329th consecutive month with global temperatures warmer than the 20th century average. The last time global temperatures were below average was February 1985. Global satellite-measured temperatures in July for the lowest 8 km of the atmosphere were 7th or 5th warmest in the 34-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH). Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of July in his July 2012 Global Weather Extremes Summary.



Figure 1. Departure of temperature from average for July 2012. Most areas of the world experienced much higher-than-average monthly temperatures, including most of the United States and Canada. Meanwhile, Australia, northern and western Europe, eastern Russia, Alaska, and southern South America were notably cooler than average. Image credit: National Climatic Data Center (NCDC) .

El Niño watch continues
Sea surface temperatures increased to 0.8°C above average as of August 13 in the equatorial Pacific off the coast of South America. Ocean temperatures have been near or above the 0.5°C above average threshold needed for a weak El Niño event since the beginning of July. However, winds, pressures, and cloud cover over the region have not responded in the fashion typically associated with an El Niño, and NOAA's Climate Prediction Center (CPC) said that "The lack of a clear atmospheric response to the positive oceanic anomalies indicates ongoing ENSO-neutral conditions," in their August 9 El Niño discussion. They have issued an El Niño watch, and give a 71% chance that an El Niño event will be in place by September. El Niño conditions tend to decrease Atlantic hurricane activity, by increasing wind shear over the tropical Atlantic. Wind shear has been close to average over the tropical Atlantic since the beginning of hurricane season in June, though.


Figure 2. Arctic sea ice extent in 2012 (black line) compared to the previous record low year of 2007 (blue line) shows that 2012 is fast approaching all-time record territory. A big Arctic storm with a central pressure of 963 mb affected the ice during the first two weeks of August, causing a temporary downward spike in sea ice extent. Image credit: Danish Meteorological Institute.


Figure 3. View of the North Pole on August 17, 2012 from the North Pole Environmental Observatory shows plenty of melt water pools from the warm summer the North Pole has had.

Arctic sea ice falls to 2nd lowest extent in July, nears all-time record low during August
July 2012 Arctic sea ice extent reached its 2nd lowest July extent in the 35-year satellite record, according to the National Snow and Ice Data Center (NSIDC). During the first half of August, sea ice has undergone a spectacular decline, and we are on pace to break the all-time lowest sea ice extent record set in September 2007. As of August 17, the University of Bremen was showing that sea ice extent has already broken the all-time record; the Danish Meteorological Institute put the ice loss in 2nd place behind September 2007; and the National Snow and Ice Data Center put Arctic ice loss in 3rd place behind September of 2007 and 2011.

Update on 94L
A large tropical wave (Invest 94L) located a few hundred miles southwest of the Cape Verde Islands off the coast of Africa is headed west at 15 - 20 mph. This storm is a threat to develop into a tropical storm that will affect the Lesser Antilles Islands as early as Wednesday. The storm is under moderate wind shear of 10 - 20 knots, and is over waters of 28°C. A large area of dry air lies just to the north of 94L, as seen on the latest Saharan Air Layer (SAL) analysis. Satellite loops show that 94L has increased in organization this afternoon, with a growing amount of heavy thunderstorm activity and spin at middle levels of the atmosphere.


Figure 4. Afternoon satellite image of Invest 94L.

Forecast for 94L
The latest 2 pm EDT run of the SHIPS model predicts that wind shear will be low, 5 - 10 knots, and ocean temperatures will fluctuate around 28°C over the next five days, as 94L tracks westwards towards the Lesser Antilles. As is typical with storms making the crossing from Africa to the Antilles, dry air to the north will likely interfere with development, and the SHIPS model predicts increased dry air as 94L approaches the Lesser Antilles. However, with shear expected to be low, dry air may be less of an issue for 94L than it was for Ernesto or TD 7. The storm should maintain a nearly due west track through Monday night, to a point near 50°W, about 700 miles east of the Lesser Antilles. At that point, a trough of low pressure passing to the north of 94L may be able to pull the storm to the northwest well to the northeast of the Lesser Antilles, as suggested by the latest 12Z (8 am EDT) run of the NOGAPS model. The 12Z UKMET model shows a more west-northwesterly motion resulting in a near miss of the Lesser Antilles on Thursday. Our two best performing models--the GFS and ECMWF--have both been taking 94L through the Lesser Antilles with every run for the past 24 hours, though. The latest 12Z run of both models now agree on the timing, with 94L arriving Wednesday night or Thursday morning. The BAMM model, which performed as well as the ECMWF and GFS at 5-day forecasts in 2011, is also showing a track through the Lesser Antilles. Given this agreement among our top three models for long-range forecasts, I give a 60% chance that 94L will pass through the Lesser Antilles. In their 2 pm EDT Tropical Weather Outlook, NHC gave 94L a 50% chance of developing into a tropical depression by Monday afternoon.

Jeff Masters

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Quoting AussieStorm:


I would be surprised if storm surge was a problem. Islands don't normally have a problem with storm surge as it doesn't have a chance to build up. Maybe big wind blown waves.
Depends on the island [and to a certain extent the storm]. Barrier type islands, like those in the Bahamas and N Australia, are much more vulnerable to surge than others, particularly washover type surge like that seen during Ike. It's possible in worst case scenarios here to see surge of 20+ feet. I think smaller volcanic islands have fewer problems with surge.
Member Since: October 25, 2005 Posts: 19 Comments: 22583
Quoting AussieStorm:

look at the Tx Coast. oppps.


Helene returns...
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1353. will40
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Quoting gustavcane:
I think Hurricane Gordon is not  weakening right now. I think the eye is re establishing its self  in the from of an eyewall replacement cycle. Gordon did this same thing last night that it is doing right now as in looking like the eyewall was going to collapse and it did not.


It's true the eye is holding together very well.

I was just now looking at the infrared myself, so I guess I'll be waiting on the next shortwave frame too.

The dry air did penetrate the eye wall about an hour or so ago, but it has closed back off again.

Still, it's going to run out of heat very soon now.
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1351. JLPR2


I'm just not sure...
That low in the CATL apparently is the one that is currently in front of 94L, it moved to the SE around 94L and was left behind. Anyone think that could actually happen?
Member Since: September 4, 2007 Posts: 7 Comments: 8747
1350. sar2401
Quoting AussieStorm:


Mt Pinatubo had major lahar flows as there was a TS passing at the same time as the eruption was occurring.


True, speaking of the perfect storm. Typhoon Yunya and the second biggest volcanic eruption of the 20th century at the same time. I was at Clark AFB about six months before the eruption. It was hard to believe the total damage caused to the base by the combination of the ash mixed with rain. I don't think one hangar was intact after the first two days.
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1349. GetReal
108 hours



Showing some signs of getting act together, ridge to north still holding in place.
Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting Stormchaser121:

Reasonable solution
outdated model run
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Quoting Stormchaser121:

Reasonable solution

look at the Tx Coast. oppps.
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certainly intensifying south of PR this run, still weaker than it was, but looks stronger than the 18Z run
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Quoting gustavcane:
I think Hurricane Gordon is not  weakening right now. I think the eye is re establishing its self  in the from of an eyewall replacement cycle. Gordon did this same thing last night that it is doing right now as in looking like the eyewall was going to collapse and it did not.


I see a nice chunk of dry air in the western side just outside of the eyewall.
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1343. GetReal


Still moving amazingly fast because of that blocking high to the north.
Member Since: July 4, 2005 Posts: 204 Comments: 8898

Reasonable solution
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Quoting Tygor:


Seems like the rain is past San Antonio, even though there's lightning everywhere. 0.05" and it's the most we've seen since that July 15th you're talking about.


We went to my Mother in Laws, near 410 & Fredricksburg. There was a thunderstorm. Just got home near Bandera Pointe. Roads are dry, like usual.
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1340. will40
looks like the ridge may break down around 96 hrs
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Gordon looks really really good despite that hole in his convection.
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1336. GetReal
Quoting Hurricanes101:


gfs is notoriously bad on intensity


I agree... 94L should at least be a strong TS at this point. IMO
Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting GetReal:
84 hours



Coming into central Lesser Antilles as a TD, probably due to the fast forward speed mentioned before.


gfs is notoriously bad on intensity
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1334. GetReal
84 hours



Coming into central Lesser Antilles as a TD, probably due to the fast forward speed mentioned before.
Member Since: July 4, 2005 Posts: 204 Comments: 8898
I think Hurricane Gordon is not  weakening right now. I think the eye is re establishing its self  in the from of an eyewall replacement cycle. Gordon did this same thing last night that it is doing right now as in looking like the eyewall was going to collapse and it did not.
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The fury of Andrew
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Quoting sar2401:


The Azores have very good disaster plans in place. There are hurricane shelters located well above the storm surge line that those who might be in danger can evacuate to. There's no way to evacuate the islands in any timely fashion. The islands have been hit or brushed by three cat 1's that we know of, and the islands have come through with very little damage, except to the power grid.


Interesting to know. I remember you said you had gone diving there.
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1330. GetReal
72 hours

Member Since: July 4, 2005 Posts: 204 Comments: 8898
1329. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 175 Comments: 54858
Quoting BahaHurican:
Hmmmm... I hadn't heard that before... certainly something to read up on, since I'd like to understand the dynamics of that.


The storm's worst quadrant in term of windspeed, is dependent on the direction the storm is moving.

In the northern hemisphere, where cyclones rotate counterclockwise, the worst quadrant would be:

NE: if the storm is generally moving north
NW: if the storm is generally moving west
SE: if the storm is generally moving east, and
SW: if the storm is generally moving south
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I don't think most of us really give much thought to how fast elevation changes on volcanic islands.

Anybody who cares can probably walk just a mile or two inland and escape the worst imaginable storm surge.
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Quoting sar2401:


The Azores have very good disaster plans in place. There are hurricane shelters located well above the storm surge line that those who might be in danger can evacuate to. There's no way to evacuate the islands in any timely fashion. The islands have been hit or brushed by three cat 1's that we know of, and the islands have come through with very little damage, except to the power grid.


I would be surprised if storm surge was a problem. Islands don't normally have a problem with storm surge as it doesn't have a chance to build up. Maybe big wind blown waves.
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1325. GetReal
60 hours



That STRONG Bermuda high is the culprit that has 94L moving so fast, not allowing it to become a major system. If this Bermuda ridge holds in place, the first chance that 94L will have to slow down and grow will be the NW Carib. imo
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1324. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 175 Comments: 54858
1323. sar2401
Quoting gustavcane:
Gordon will be bad for the Azores island. Even if Hurricane Gordon is not a Hurricane and is Ex Tropica
( which i doubt will be the case being how strong it is right now ) with its fast forward speed of 22 MPH and may  increase to 30+ MPH it
will bring a very strong and destructive and very high storm surge to
the coast of the Azores Island. Please, I hope they  evacuate to higher
ground or off that Island as soon as possible.


The Azores have very good disaster plans in place. There are hurricane shelters located well above the storm surge line that those who might be in danger can evacuate to. There's no way to evacuate the islands in any timely fashion. The islands have been hit or brushed by three cat 1's that we know of, and the islands have come through with very little damage, except to the power grid.
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1322. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 175 Comments: 54858
1321. GetReal
48 hours




"Helene" 1008mb; 94L 1012mb

STRONG Bermuda ridge to north of 94L
Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting sar2401:


Certainly makes sense, and it's hard to tell an eyewall replacement cycle from a storm which is just starting to deintensify. As you wrote, we'll know for sure by tomorrow morning. Good luck with your studies. Eyewalls and eyewall replacement cycles are one of the most mysterious parts of how hurricanes work.

Thank you. That is exactly why I am so fascinated with them. I feel like if we understand hurricane eyewalls and eyewall replacement better, intensity forecasts will improve by a large margin.
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Dry air monster...




BTW, Gordon's outflow is still a mystery. Somebody at NHC probably needs to write a paper on it or something.
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Quoting Methurricanes:
Its the Right/Front quadrent relative to the movement of the storm, due to storms usually making landfall going NW/N not East the NE quadrent is seen as the worst but a Eastward moving storm is strongest where the winds are moving east Ie- the South side.


for the landslide Debate- Read post 297.
Thanks for the simple, clear explanation. I definitely will read up some more about this tomorrow, as I now realize I haven't thought much about WHY the strongest quadrant is the NE... just took it "as read".
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1317. GetReal
30 hours:



Activity in W. GOM is alive!
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1316. sar2401
Quoting 1900hurricane:

I don't think it is as unlikely as you think. However, you are correct about Gordon losing organization. Every hurricane will at least temporarily lose organization during eyewall replacement, and this loss of organization leaves the hurricane in a more vulnerable state, allowing other factors such as shear or dry air to have a greater impact on it than it would when not in eyewall replacement, and causes the hurricane to lose even more organization, interrupting eyewall replacement. That is what I think we are possibly seeing right now, and we should know for sure by tomorrow morning.

I have personally spent a great deal of time studying hurricane eyewalls and eyewall replacement. This is many years down the road yet, but if all goes well, I would like to write my doctorate about eyewall replacement.


Certainly makes sense, and it's hard to tell an eyewall replacement cycle from a storm which is just starting to deintensify. As you wrote, we'll know for sure by tomorrow morning. Good luck with your studies. Eyewalls and eyewall replacement cycles are one of the most mysterious parts of how hurricanes work.
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Member Since: September 18, 2010 Posts: 0 Comments: 5237
Quoting RTSplayer:


That's a huge presentation.

That will take a while to even scan fully, and I'm a good reader.


Tropics and climate change explanations begin on page 199. Here's the link again for everyone.

Link
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Models are trending towards an even stronger ridge, but on the flip side...they are also significantly weaker with 94L than before.

Moral of the story: Don't get your hopes up.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
Local Tampa met mentione 94 "looking really good" and made a special note about the one behind it. So, let's see how the gfs 00z handles it. Just started it's output
Member Since: August 26, 2006 Posts: 0 Comments: 1548
Gordon will be bad for the Azores island. Even if Hurricane Gordon is not a Hurricane and is Ex Tropica
( which i doubt will be the case being how strong it is right now ) with its fast forward speed of 22 MPH and may  increase to 30+ MPH it
will bring a very strong and destructive and very high storm surge to
the coast of the Azores Island. Please, I hope they  evacuate to higher
ground or off that Island as soon as possible.
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Quoting BahaHurican:
Hmmmm... I hadn't heard that before... certainly something to read up on, since I'd like to understand the dynamics of that.
Its the Right/Front quadrent relative to the movement of the storm, due to storms usually making landfall going NW/N not East the NE quadrent is seen as the worst but a Eastward moving storm is strongest where the winds are moving east Ie- the South side.


for the landslide Debate- Read post 297.
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Quoting 1900hurricane:

I don't think it is as unlikely as you think. However, you are correct about Gordon losing organization. Every hurricane will at least temporarily lose organization during eyewall replacement, and this loss of organization leaves the hurricane in a more vulnerable state, allowing other factors such as shear or dry air to have a greater impact on it than it would when not in eyewall replacement, and causes the hurricane to lose even more organization, interrupting eyewall replacement. That is what I think we are possibly seeing right now, and we should know for sure by tomorrow morning.

I have personally spent a great deal of time studying hurricane eyewalls and eyewall replacement. This is many years down the road yet, but if all goes well, I would like to write my doctorate about eyewall replacement.


Irene was a great example. When she underwent EWRC, she sucked in dry air and couldn't complete it, so as a result it weakened.
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Quoting AussieStorm:

Eye looks ragged and there is dry air about to hit the eye very soon
That's not dry air.
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Quoting gustavcane:
Gordon is a perfect Doughnut  right now and the center is locked and
shielded from any dry air. excellent outflow in all 4 quadrants a true
sign of a rapid intensifying Hurricane. This is a true textbook image
IMO. what do you guys think.

Eye looks ragged and there is dry air about to hit the eye very soon
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1306. GetReal
Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting sar2401:


Looks to me like Gordon is starting to lose organization as it enters a more hostile enviroment. An eyewall replacement cycle seems unlikey, but everything about Gordon has seemed unlikely. :)

I don't think it is as unlikely as you think. However, you are correct about Gordon losing organization. Every hurricane will at least temporarily lose organization during eyewall replacement, and this loss of organization leaves the hurricane in a more vulnerable state, allowing other factors such as shear or dry air to have a greater impact on it than it would when not in eyewall replacement, and causes the hurricane to lose even more organization, interrupting eyewall replacement. That is what I think we are possibly seeing right now, and we should know for sure by tomorrow morning.

I have personally spent a great deal of time studying hurricane eyewalls and eyewall replacement. This is many years down the road yet, but if all goes well, I would like to write my doctorate about eyewall replacement.
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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.