| Tropical Storm Katia |
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| Date: | September 4, 2011 |
| Time: | 10AM EST |
| Winds: | 75 mph |
| Pressure: | 987 mbar |
Giving a morning update because something interesting has happened with Katia. Katia has moved within 19 miles of an observation buoy in the ocean that has allowed very accurate data. Based on the 1 minute sustained wind direct observation, Katia could be upgraded to 85mph winds at 11AM EST.
| Time | Wind Direction | Wind Speed (kt) | Wind Speed (mph) |
| 8:50 am | SE ( 137 deg ) | 71.5 kts | 82 mph |
| 8:40 am | SE ( 124 deg ) | 70.7 kts | 81 mph |
| 8:30 am | ESE ( 117 deg ) | 70.1 kts | 80 mph |
| 8:20 am | ESE ( 112 deg ) | 69.2 kts | 79 mph |
| 8:10 am | ESE ( 111 deg ) | 70.7 kts | 81 mph |
| 8:00 am | ESE ( 112 deg ) | 67.2 kts | 77 mph |
- At 8:51AM EST the buoy detected a brief low pressure of 28.71in, or about
972 millibars
- At 8:55AM EST the buoy detected a sustained wind of
85mph (73.8kts)
UPDATE: An hour later the Hurricane Center upgraded Katia to 100mph and 966mb pressure. I do not know how they got 100mph winds and a pressure so low when the eye basically went right over the buoy.
| Tropical Storm Katia |
|
| Date: | September 3, 2011 |
| Time: | 7PM EST |
| Winds: | 70 mph |
| Pressure: | 993 mbar |
As expected, my instinct to let the models adjust to newer data and not jump to conclusions like weathermen do has proved to be a wise decision. All day today models are back to showing Katia curving to the NORTHEAST.
The most obvious sign that it will make that curve may not occur until Thursday. Until then it may appear to the average person that Katia will strike the lower US.
Katia is technically a Tropical Storm now with 70mph winds. As mentioned earlier the constant reclassifying from Hurricane to Tropical Storm is irrelevant. There's virtually no difference.
The National Hurricane Center is slowly shifting their forecast to the north. The images below show their slow progression / acknowledgement that Katia will be curving to the NORTH.
| 9/2/11 11PM |
9/3/11 11AM |
9/3/11 5PM |
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The following image shows the all but certain path Katia will take. Models since August 28th, 6 days ago of this posting, have continuously shown that Katia will curve away from the US near Bermuda.
Note: The outline of the US is drawn in
- Mike DeLeonardis
(Twitter: @ecography)
| Hurricane Katia |
|
| Date: | September 2, 2011 |
| Time: | 10PM EST |
| Winds: | 75 mph |
| Pressure: | 989 mbar |
The past two days have been quite interesting. Needless to say hurricane forecasting is far from perfect. I have been watching various models hourly for the past two days and some peculiar observations have occurred.
Yesterday numerous models were showing a high pressure trough crossing from the west coast to the east coast and merging with the Azores high.
If this played out it would basically prevent Katia from curving north and would cause Katia to move westward towards the US.
Models today are not showing such a drastic blockage. To much surprise, a major factor in the severity of how much this trough will be an impact is Tropical Storm Talas over 7,000 miles away near Japan.
A major factor inhibiting Katia from strengthening further is much higher than expected wind shear from the NORTHWEST.
I'm not going to write about a forecast in this post because there are just way too many variables in the models now and I want to give them another day to iron themselves out. Instead I will explain the atmospheric forces affecting Katia.
Wind Shear
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The following two images are the same but one I drew on to show rotation.
(I hate when people draw on images where you can't see the actual image which is why I have the original and one drawn on.)
Wind shear can tear a storm apart or prevent strengthening. In the image you can see counter-clockwise rotation around Katia. You can also see winds coming from the NORTHWEST, hitting Katia, and curving NORTHEAST. I've circled the area where major shear has occured. Basically it's the same as an airplane flying into wind. The wind will slow the airplane down slightly. The same happens with hurricanes. By there being wind shear significant enough it slightly distorts the NORTHERN part of Katia.
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High Pressure Trough
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(The ball of circles in the center bottom of each image is Katia.) The high pressure location and intensity is one major variable in determining the path Katia takes.
Unfortunately this is one of the major steering currents of a hurricane. The image on the LEFT shows one forecast model while the image on the RIGHT shows a different model. Both models show about the same time. As you can see on the LEFT there are lots of yellows and greens, or lower pressures. These lower pressures allow storms to go into those waters. The image on the RIGHT shows that high pressure creating a huge orange/red blob, or very high pressure. Hurricanes generally cannot penetrate these higher pressures but instead go around them clockwise. The ultimate fate of this pressure will unfortunately not be somewhat known until Sunday.
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- Mike DeLeonardis
(Twitter: @ecography)
September 1st, 2011
Katia was a tropical storm gathering energy over the Atlantic Ocean when one of the Expedition 28 crew took this photo on Aug. 31, 2011, from aboard the International Space Station. The picture, taken with a 12-mm focal length, was captured at 14:09:01 GMT. Later in the day Katia was upgraded to hurricane status. Two Russian spacecraft -- a Progress and a Soyuz --can be seen parked at the orbital outpost on the left side of the frame.
Image Credit: NASA
| Tropical Storm Katia |
|
| Date: | August 31st, 2011 |
| Time: | 5PM EST |
| Winds: | 70 mph |
| Pressure: | 990 mbar |
Katia is now an extremely strong Tropical Storm withw inds of 70mph.
The following diagram I created shows a very basic explanation of why Katia will be curving to the NORTH. The image on the (RIGHT) is the current model of Katia.
To the north of the green concentric circles on the bottom of the image is a huge orange colored blob.
This blob represents high pressure of about 1020 to 1030 millibars (standard atmospheric pressure is about 1013 millibars). Storms move around high pressure systems in a clockwise direction.
Generally the wider the high pressure system is extending to the west (USA), the further a storm travels to the west before curving north.
Models are in much agreement that there will be a break in the high pressure a few hundred miles west of the eastern US coast. The image on the (LEFT) shows how a lot of the orange colors in the (RIGHT) image have turned to yellow (1012 to 1016 millibars, or about standard atmospheric pressure). This break will not block Katia from moving to the north and most likely will allow the storm to curve away a few hundred miles away from the US coast.
| There is currently the potential for a Tropical Storm to hit anywhere from the Florida Panhandle to East Texas this weekend.
Models are showing a good possibility that Tropical Storm Lee will be formed.
The following image shows potentially Lee, and Katia in in the Gulf and Western Atlantic on Sunday. |
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- Mike DeLeonardis
(Twitter: @ecography)
| Tropical Storm Katia |
|
| Date: | August 30th, 2011 |
| Time: | 9PM EST |
| Winds: | 60 mph |
| Pressure: | 997 mbar |
Tropical Storm Katia has quadrupled its strength from 30mph to 60mph in about 24 hours. In the next 4 days it is projected to quadruple once again to 120mph. So far 120mph seems to be the max wind prediction I have seen.
Katia is still projected to become a major hurricane by Saturday. Models are still suggesting the storm will curve to the NORTH a few hundred miles east of Florida.
The image on the (LEFT) shows the current intensity forecasts. The 84-hour forecast consensus shows a strong agreement of a Category 3 hurricane with winds between 111 and 130 mph.
I do not think Katia will get much stronger than a Category 3 since the consensus is that it will curve to the north and thus enter colder waters at that point.
The image on the (RIGHT) shows an infrared / visible composite of Katia. You can see extremely well-defined rotation by the spiral cloud bands.
| Tropical Storm Katia |
|
| Date: | August 29th, 2011 |
| Time: | 5AM EST |
| Winds: | 40 mph |
| Pressure: | 1006 mbar |
Tropical Storm Katia should form soon most likely in the morning when the sun rises in the far Eastern Atlantic Ocean. I'm jumping the gun a bit but all signs point to this developing into Katia.
Katia has just about everything going for it that a storm can to rapidly develop into a Tropical Storm / Hurricane.
The visible satellite image below (LEFT) shows a classic tropical wave transition into a tropical storm.
The fact that Katia created this vivid rotation so quickly is an indicator of how favorable the Atlantic is for hurricane development.
Any time a developing storm gets that saw blade like composition there is generally massive suction going on in the center of the storm.
The (MIDDLE) image shows very concentric pressure circles indicating Katia is forecast to be a very severe storm. The rounder and closer together the isobars are the lower the central pressure and stronger the storm.
This is an estimate of 5-8 days out depending on the forward speed of Katia.
The 24-hour pressure change image (RIGHT) shows a deep red, orange, and yellow indicating rapid depressurization.
The above shows the intensification for Katia, but what about where it is going? According to a consensus of 20 computer models (LEFT) Katia is projected to make a curve to the NORTH a few hundred miles to the west of Florida.
Most models are in agreement that the Azores High will weaken considerably over the next week allowing Katia to move to the north.
The image on the (RIGHT) is the North American Ensemble Forecast Model. This model is a mix of rain and atmospheric pressure. You can see from the legend on the left that Katia is projected to be quite intense as it begins its NORTH trajectory.
It's not clear in the image but the system is moving NORTH and not EAST towards Florida.
So far all models suggest Katia will curve to the NORTH and out to sea 7-10 days down the road if the Azores high pressure system weakens.
- Mike DeLeonardis
(Twitter: @ecography)
