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 AtHomeInTX:


Is that just rain? Maybe I read it wrong. Wouldn't be the first time. :)




So models are showing Houston storm. I thought Tillman was wish casting.lol
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Quoting unknowncomic:
Also your map shows a huge low in the northwest pacific--that will affect something.
Make that northeast Pacific.
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Quoting SFLWeatherman:
6Z 186HR


Lot of ensemble members still developing it despite the operational not doing so.
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Quoting hydrus:
The GFS shows that whatever is left of 94 after crossing Hispaniola and Cuba is situated off the S.W.Florida coast. This is of course to far out to take seriously, but it does show that it still is possible for it to make the gulf. The 192 shows it skirting the Cuba coast near the Florida Straits.
Also your map shows a huge low in the northwest pacific--that will affect something.
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Quoting CaicosRetiredSailor:


Pinhole?
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Quoting nrtiwlnvragn:
Mostly along track uncertainty with experimental ensembles:





potentially a lot of mountainous terrain along that path. Not good for those in the path but, good for interests in the US. Not many cyclones survive a path like that.
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Quoting yonzabam:


Possibly an underrated factor, hindering cyclogenesis throughout the region. Last year, many expected storms failed to materialise or were well below predicted strength. Sinking air was suggested as a reason. It's been the same this year, and the intense drought is believed to be a cause.

High forward speed also--that will change.
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1698. hydrus
Quoting VR46L:


The love child of Helena still needs to be watched out for IMO...had some model support for either Houston or NOLA at differing times .. and there are some interesting bloblets in the western Gulf ... Just saying....


rainbow image


funktop Image

Looks terrible, but I do not trust anything in the gulf this time of year, and I mean anything...I have seen the most pathetic looking system spin up into a dangerous storm in a matter of hours. 1982 Alberto being one, which fizzled almost as fast as it formed. The No-Name Storm that same year caught everyone of guard too.
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This Is My New Video Blog For Sunday Link
Press refresh if the old video is still up.
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1696. pottery
Quoting stormpetrol:


The wave just ahead of 94L has a much tighter circulation!

I had noticed that too.
Very far south for circulation....
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Lots of rain for today in S. Louisiana.



Rivers are all bone dry anyway, so that's not a concern, but there's still going to be street flooding from this for sure in places with bad drainage.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Mostly along track uncertainty with experimental ensembles:



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1693. hydrus
Quoting pcola57:


Now that my friend will make a "considerable" difference..a uh oh moment as it were.. :)
The GFS shows that whatever is left of 94 after crossing Hispaniola and Cuba is situated off the S.W.Florida coast. This is of course to far out to take seriously, but it does show that it still is possible for it to make the gulf. The 192 shows it skirting the Cuba coast near the Florida Straits.
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Quoting stormpetrol:


The wave just ahead of 94L has a much tighter circulation!
yeah but 94L has a nice anticyclonic spin to it :)
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6Z 186HR

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1690. sar2401
Quoting VR46L:


The love child of Helena still needs to be watched out for IMO...had some model support for either Houston or NOLA at differing times .. and there are some interesting bloblets in the western Gulf ... Just saying....


rainbow image


funktop Image



There is also a large and complex hybrid front the stretches all the way from NC to Idaho. It is a cold front moving south in some places, a warm front moving north in others, and a quasi stationary front for much of its length. It's spining off surface low pressure troughs throughout the southeast that are responsible for most of the convection currently depicted from Texas over to Florida. Anything left over from ex-Helene could get caught up in one of these troughs, but don't assume its tropical in origin when there are so many other troughs developing from this front.
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Quoting GetReal:


IMO a new COC is going to form in the SW GOM near that cluster of convection just off the coast... Welcoming back Helene from the dead.


It'll have a hell of a hard time getting re-classified, because the mid-level circulation is about 300 miles SW of the blobs...
Member Since: January 25, 2012 Posts: 33 Comments: 1520
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1687. pcola57
Quoting stormpetrol:
94L also appears to have slowed in forward speed quite a bit.


Now that my friend will make a "considerable" difference..a uh oh moment as it were.. :)
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The wave just ahead of 94L has a much tighter circulation!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
1685. hydrus
Quoting SFLWeatherman:
8AM They go up to 101KT now
And this does not bode well for the U.S. either...DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0335 AM CDT SUN AUG 19 2012

VALID 221200Z - 271200Z

...DISCUSSION...
GUIDANCE IS HIGHLY CONSISTENT THAT THE HEIGHT GRADIENT ASSOCIATED
WITH THE AMPLIFIED UPPER-LEVEL TROUGH IN THE ERN CONUS WILL FURTHER
RELAX. A SHORT WAVE TROUGH CENTERED NEAR THE NRN ROCKIES EARLY WED
SHOULD DAMPEN AS IT EJECTS EWD INTO THE NRN PLAINS/UPPER MS VALLEY
ON D4-6. RICHER LOW-LEVEL MOISTURE SHOULD BE GRADUALLY DRAWN NWD
ACROSS THE PLAINS...BUT KINEMATIC FIELDS APPEAR TO REMAIN MODEST.
THEREAFTER...A MORE VIGOROUS SHORT WAVE TROUGH MAY ADVANCE FROM SWRN
CANADA/PACIFIC NW TOWARDS THE CANADIAN PRAIRIES/FAR NRN PLAINS NEXT
WEEKEND. BUT STRONGER MID-LEVEL FLOW APPEARS TO BE WELL-REMOVED FROM
THE WARM SECTOR/FRONTAL BOUNDARY IN THE N-CNTRL CONUS. THESE SETUPS
DO NOT APPEAR SUPPORTIVE OF HIGHER-END SEVERE COVERAGE.

..GRAMS.. 08/19/2012
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.
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1683. GetReal


IMO a new COC is going to form in the SW GOM near that cluster of convection just off the coast... Welcoming back Helene from the dead.
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Quoting ProgressivePulse:
Thoughts from the NHC @ 72hrs.



My thoughts on that is they are going with the BAMM for now, since the most recent GFS disregards 90% of it's own members. I don't know what it does to weight it's averages, but it just looks...unnatural right now.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
1681. scott39
Quoting stormpetrol:
94L also appears to have slowed in forward speed quite a bit.
agreed
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94L also appears to have slowed in forward speed quite a bit.
Member Since: April 29, 2007 Posts: 0 Comments: 8134
1679. hydrus
Quoting rmbjoe1954:


I wonder why GFS is so far south then its ensembles?
One thing is for sure, if 94L remains below hurricane status when it hits the Lesser Antilles, there is a much greater chance that it could make it to the Gulf of Mexico. I believe that it will NOT make it to the gulf, but not out of the realm of possibility.
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BAMM wants to be Rita or Ike, and the GFS still wants to be Gustav, and the SHIPS supports the intensity in either scenario.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
384HR 6Z!?!?!



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I wouldn't lay too much credence to the improved SHIPS model as of yet. It has performed poorly this year, especially with Ernesto and TD7, which are relatively good analogs to our 94L.

If it gets going, than yeah it'll be in a position to strengthen, but I think that's much more an IF than a guarantee.

Plus looking on down the line, there could be some serious shear issue for 94L north of the islands if it ends up headed there...
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6Z 192HR


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1674. GetReal


Nearly on top of us now here in NOLA. It looks a hell of a lot worse than it probably is....
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Quoting SFLWeatherman:
8AM They go up to 101KT now


GFS has had the same basic track to DR and Haiti now for about 30 hours, 4 or 5 runs; a few tenths of a degree north or south variation is all. Only thing it changes is slight variations in what happens after that.


One thing I don't understand in this case is why the "consensus" is so far away from the ensemble members on this particular run...
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Nice image.

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1671. scott39
94Ls COC is too broad to pinpoint the exact coordinates.
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1669. VR46L
Quoting emguy:
As a footnote...don't forget to look at the Western Gulf today folks...for the spawn of Helene. There is some indication there are goings on over there. Check out the shortwave loops ;)


The love child of Helena still needs to be watched out for IMO...had some model support for either Houston or NOLA at differing times .. and there are some interesting bloblets in the western Gulf ... Just saying....


rainbow image


funktop Image

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Quoting TropicalAnalystwx13:

That's not the center. The center is at 37W 15N.


14.5 north 37 west
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Remember Irene? Irene looked worse than 94L now. it was a naked swirl at one point. saharan air is a pain for these invests. bad news is this should be a hurricane when it gets to the islands but should take a more westward track. gfs ensembles show something scary in the gulf
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1666. GetReal


IMO there is going to be some fireworks in the GOM as today goes on.
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Quoting SFLWeatherman:
8AM


I wonder why GFS is so far south then its ensembles?
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Quoting stormpetrol:


All broad centers are below at or below 12N

you can clearly see the center of 94L
on this link at around 12N/37W Link

Still very broad.
Member Since: July 6, 2010 Posts: 113 Comments: 32812
Quoting osuwxguynew:
The tropical central Atlantic is much more stable than normal as evidenced by the current anomaly and the seasonal graph below:





Possibly an underrated factor, hindering cyclogenesis throughout the region. Last year, many expected storms failed to materialise or were well below predicted strength. Sinking air was suggested as a reason. It's been the same this year, and the intense drought is believed to be a cause.

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LAT LON LAT LON LAT LON LAT LON
BAMS 18.0N 52.1W 18.4N 61.3W 18.5N 70.0W 17.8N 76.4W
BAMD 17.3N 47.4W 17.6N 52.9W 17.3N 57.5W 16.2N 59.8W
BAMM 18.2N 49.9W 18.8N 58.0W 19.8N 66.2W 21.4N 72.9W
LBAR 16.5N 49.5W 17.7N 56.6W .0N .0W .0N .0W
SHIP 58KTS 84KTS 100KTS 101KTS
DSHP 58KTS 84KTS 100KTS 101KTS


Any of these tracks are gonna suck for a lot of people if that intensity is true.

BAMM ends in the lower Bahamas and looks to have just missed all the major land masses along the way, with PR probably getting TS or hurricane force winds on the south side of the storm. After that, it would hit U.S. mainland for sure...
Member Since: January 25, 2012 Posts: 33 Comments: 1520
8AM They go up to 101KT now
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Quoting GetReal:


Remnant low that was once Helene beginning to exit Mexican coast. IMO

There is still a weak swirl.




yep its moving off
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8AM
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1657. msphar
great news. 1011 mb
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dry air is preventing 94L from developing. it wont be a hurricane going through the islands but since the GFS has been trending more west, lots of the ensembles have this in the gulf now as a very strong storm. eventually this should develop
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94L they go up to Cat 3 and 4
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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.

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