The Atlantic is quiet; Russian heat wave ends; huge 926 mb South Indian Ocean storm

By: Dr. Jeff Masters , 2:09 PM GMT on August 19, 2010

A tropical wave in the western Caribbean approaching Mexico's Yucatan Peninsula is generating disorganized thunderstorms. Wind shear is a moderate 10 - 15 knots over the region, and water vapor satellite images show that there is some dry air to the west that will interfere with any development that might occur. None of the reliable computer models develop this wave, and NHC is giving it a 10% chance of developing into a tropical depression.


Figure 1. Morning satellite image of the disturbed region of weather of the coast of Africa, south of the Cape Verdes Islands.

The GFS, NOGAPS, and ECMWF models continue to predict that a tropical storm will form between Africa and the Lesser Antilles Islands sometime in the period 3 - 6 days from now. There is an area of disturbed weather south of the Cape Verdes Islands, but there is no obvious organization to the cloud pattern. Wind shear is a hefty 20 - 30 knots in the region, and the disturbance is a 1 - 2 day journey away from reaching a lower shear area where development can occur. Preliminary indications are that if a storm did develop in this region, it would track west-northwest and pass well to the northeast of the Lesser Antilles Islands 7 - 8 days from now. However, 7-day forecasts of a storm that hasn't even formed yet are not to be trusted.


Figure 2. The cold front that brought an end to the Great Russian Heat Wave of 2010 lies east of Moscow in the NASA MODIS photo taken at 8:35 UTC August 19, 2010. Smoke from wildfires is visible over a wide swath of Russia east of the front. Image credit: NASA.

The Great Russian Heat Wave of 2010 ends
A powerful cold front swept through Russia yesterday and today, finally bringing an end to the Great Russian Heat Wave of 2010. Temperatures at Moscow's Domodedovo airport hit 25°C (77°F) today, which is still 4°C (7°F) above average, but the high temperature since late June. Moscow has seen 62 consecutive days with a high temperature above average, but the latest forecast for Moscow predicts that remarkable string will come to an end Friday, when the high will reach just 17°C (62°F).

Massive 926 mb extratropical storm generating huge waves off Antarctica
One of the most intense extratropical storms in recent years is churning up the waters near the coast of Antarctica in the South Indian Ocean. The powerful storm peaked in intensity yesterday afternoon with a central pressure of 926 mb--the type of pressure typically found in a Category 4 hurricane. Storms this intense form on average once per year, or perhaps less often, according to an email I received from Jeff Callaghan of the Australia Bureau of Meteorology. Since extratropical storms do not form eyewalls, the winds at the surface from this monster storm probably reached "only" 100 - 120 mph (equivalent to a Category 2 or 3 hurricane.) The storm is forecast to generate huge waves with a significant wave height of 13 meters (44 feet) today, according to the NOAA Wavewatch III model (Figure 3.) I have flown into an extratropical storm this intense--in 1989, I participated in a field project based in Maine that intercepted a remarkable extratropical storm that "bombed" into a 928 mb low south of the Canadian Maritime provinces. You can read my story of that somewhat harrowing flight here.


Figure 3. Satellite image taken at 8:10 UTC August 19, 2010, showing the intense extratropical cyclone that has weakened to 940 mb in the South Indian Ocean near the coast of Antarctica. Image credit: NASA.


Figure 4. Surface pressure analysis from 18 UTC August 18, 2010, showing a 926 mb low in the South Indian Ocean, just north of Antarctica. Image credit: Jeff Callaghan, Australia Bureau of Meteorology.


Figure 5. Predicted wave height from the NOAA Wavewatch III model for 2pm EDT (18 UTC) today, August 19, 2010. Peak wave heights of 13 meters (44 feet) are projected over ocean areas between Antarctica and Australia. Long-period waves (19 seconds between crests) up to 7 meters (22 feet) high are predicted to affect the southwest coast of Australia by Sunday. The waves are predicted to propagate eastwards to New Zealand 8 - 9 days from now, and be a respectable 4 - 5 meters high then.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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Quoting Drakoen:
ASCAT, no signs of a surface circulation yet:



Nice little windshift though..
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Quoting troy1993:
Is there anychance this potential cape-verde system could threaten the Northeast?



No one knows right now, VERY far out.
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Quoting troy1993:
Is there anychance this potential cape-verde system could threaten the Northeast?


It's too early to tell, it may or may not.
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Is there anychance this potential cape-verde system could threaten the Northeast?
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ASCAT, no signs of a surface circulation yet:

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Quoting KanKunKid:
If your "quote" button doesn't work right, log out and log back in and it will work.

If your "modify comment" button doesn't work, just try it twice and it will. Just FYI for those frustrated like I was.


I finally gave up and stopped using IE. Firefox doesn't do that.
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Thanks,Dr. Masters!
sit back and watch is the words for the day.Enjoy the quiet times.
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Quoting clwstmchasr:


IMO nothing has changed. The first couple of systems formed in the Caribbean and were forced westward. If the current disturbance in the Caribbean were to form it too would be forced westward.

The CV systems always have a tendency to move poleward. The current setup is very common. Let it play out and see what happens.
Thanks.
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The current TW looks like Pre-Bill from last year.. Invest 90L I think
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Quoting nola70119:
"However, 7-day forecasts of a storm that hasn't even formed yet are not to be trusted."

LOL


EXACTLY what I was pointing out earlier on the last blog.
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Thanks DRM. :)
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Thx Doc...
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2106. AllBoardedUp 1:44 PM GMT on August 19, 2010
I remember at the very beginning of the season some people on here (maybe Storm being one of them) stated that because of the atmospheric conditions, Texas was going to be in the bull's eye, so to speak. It started out that way with the first two storms. My question is, what changed, if anything, and are the chance of a Texas hit less now? Sure not complaining if the chances are less, just curious.
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Thanks for the update.Going to be some sizeable surf along Australia's southern coastline at Margaret River & Torquay.
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Note the curvature of the shear over the disturbance, seems to me something anti-cyclonic might be trying to set up.
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"However, 7-day forecasts of a storm that hasn't even formed yet are not to be trusted."

LOL
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Quoting duajones78413:
Is this the current blog?


Yes, the rest will be in momentarily......
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Thanks so much Dr. Masters!
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Thanks Doc.
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Is this the current blog?
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Wow, what a powerful storm, thanks for the update and information Dr. Masters
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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