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Hanna hanging around, Ike wandering west

Now that Gustav is onshore and blowing himself out, all eyes have turned to Hanna, who was upgraded to a hurricane today. Earlier today Hanna showed some very strong convection but since that has seemed to blow herself out. Considering that her motion has been nearly stationary it seems likely that the increased winds due to the convective burst in turn caused turbulent upwelling of cold water from below. This cold upwelling has likely combined with moderate to strong shear to limit Hanna's strength.

20080902.0215.goes12.x.ir1km.08LHANNA.70kts-980mb-219N-723W.100pc.jpg
Hanna - Infrared satellite

Considering the near stationary motion and relatively high shear in the short term, strengthening seems unlikely. I'm actually going to go against the National Hurricane Center in this forecast and predict Hanna to weaken to a strong tropical storm at some point tomorrow due to the mixing of the cold water from below.


Hanna - Watches and Warnings

NHC also recently commented that the model tracks look surprisingly well clustered at this time. I don't know what model tracks they have been looking at, but they are not the same ones that I am seeing! The models are calling for landfall anywhere from Havana to Cape Hatteras! At this point anyone with interests from Cocoa, FL to the Outer Banks, NC should continue to monitor Hanna closely. Given the proximity of Hanna to the Gulf Stream, it seems likely that Hanna will maintain her strength or strengthen in her final approach to shore... no matter what her strength at that time.

To see all the models and charts for Hurricane Gustav, check out the Hanna charts page.

Click for full size model imagery:

Hanna - Track Forecast

Hanna - Wind Speed Forecast

Elsewhere in the Atlantic, Tropical Storm Ike is looking like an unimpressive storm still slowly moving toward the western Atlantic. Fortunately for us, we still have a long time to watch the storm. Gradual intensification seems likely, but without a landmass in the way Ike will likely remain a spatially compact storm in the short to medium term.

20080902.0215.goes12.x.ir1km.09LIKE.45kts-1005mb-179N-409W.100pc.jpgbr>Ike - Infrared satellite

Ike currently is packing maximum sustained winds of 50 mph, but gradual strengthening is likely over the next couple of days. However, we have little to go by in making this forecast other than climatological norms.

To see all the models and charts for Tropical Storm Ike, check out the Ike charts page.


Ike - Watches and Warnings
Click for full size model imagery:

Ike - Track Forecast

Ike - Wind Speed Forecast

Posted by Bryan Woods | Permalink


Gustav falls to category two -- "worst case scenario" avoided

The center of Hurricane Gustav is under 75 miles from New Orleans, LA and -- to the relief of many New Orleans residents, has dropped in intensity to 110 mph, or category two on the Saffir-Simpson hurricane scale.

The storm is currently making landfall on the Southeastern Louisiana coast, approximately 15 miles from Cocodrie, LA.

Though the difference between 110 mph and 115 mph is negligible, the psychological effect of dropping from a category three storm to a category two is significant. The National Hurricane Center considers a 115mph storm to be a "major hurricane" -- but make no mistake, this is absolutely still a very strong storm which still has the potential to do a number of New Orleans and the rest of southeastern Louisiana.

20080831.1915.goes12.x.ir1km.07LGUSTAV.100kts-960mb-259N-867W.100pc.jpg
Gustav - Visible satellite

Gustav is a massive storm, with hurricane force winds extending more than 70 miles from the center and tropical storm force winds extending 230 miles. The storm will also dump a ton of rain on the landfall area, with rainfall amounts of 6-12 inches plus isolated pockets of 20" is possible.


Gustav - Watches and Warnings

Posted by Jordan Golson | Permalink

Gustav eyes Louisiana landfall as Category 3 "Major Hurricane"

Hurricane Gustav is actually having a surprisingly difficult time strengthening in the Gulf of Mexico. Gustav has just passed an area of very warm water, so its fuel is becoming slightly more limited. It also is showing less symmetric convection, which is an indication of shear holding back the intensity of the system. The lopsidedness of the storm is comforting as it means Gustav is not as strong as he could be at this time.

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Gustav - Infrared satellite

Gustav is still a Category 3 hurricane with maximum sustained winds of 115 mph and a central pressure of 960 mb. His track is also following right along with the computer model and NHC forecasts. The official forecast from NHC looks pretty reliable, calling for landfall as a Cat 3 in southeast Louisiana.


Gustav - Watches and Warnings

Interestingly, it looks like Gustav will soon clear out an eye again. Convection has wrapped mostly around the center and further intensification seems probable at this point. Microwave satellite imagery is doing a fine job of showing this partial eyewall and asymmetric convection.

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Gustav - TRMM Microwave imagery

The model guidance is showing a surprising amount of spread regarding landfall tracks and intensity estimates remain a joke at this time. Forecasting storm intensity very much resembles "throwing darts." However, thus far the GFDL has done a very good job forecasting the storm and remains my model of choice. Confidence in the intensity 'remains low.'

To see all the models and charts for Hurricane Gustav, check out the Gustav charts page.

Because of Hurricane Gustav, Senator McCain announced Sunday that activities at the Republican National Convention in St. Paul, MN have been suspended except for "necessary business." McCain called on party members to "take off our Republican hats and put on our American hats."

Click for full size model imagery:

Gustav - Track Forecast

Gustav - Wind Speed Forecast

Elsewhere in the Atlantic, Tropical Storm Hanna is still slowly moving toward the Bahamas. Fortunately for us, she is not expected to be a real threat for another few days. Her satellite signature remains asymmetric, ragged, and relatively disorganized.

20080831.1915.goes12.x.ir1km.08LHANNA.40kts-997mb-235N-711W.100pc.jpg
Hanna - Infrared satellite

Hanna currently is packing maximum sustained winds of 45 mph, but for the next couple of days we are going to focus on Gustav. However, if you have interests along the Southeast coast late this week, please keep a close eye on Hanna. We could be dealing with another landfalling U.S. hurricane by Friday.

To see all the models and charts for Tropical Storm Hanna, check out the Hanna charts page.


Hanna - Watches and Warnings
Click for full size model imagery:

Hanna - Track Forecast

Hanna - Wind Speed Forecast

Posted by Bryan Woods | Permalink

Gustav has his sights on Louisiana

Wow, life has been busy. Being the graduate and professional student president at Yale really does keep me on my toes! Anyhow, you really want to know about Gustav. The good news is that Haiti has taken a serious toll on the storm. Gustav remains weak and is having issues reorganizing. However, while this is good news for Cuba, it doesn't meant much for the northern Gulf Coast. If you have interests in that area, now is the time to begin planning for preparations. If you leave along the coast, or especially below sea-level, you should already have an evacuation plan in place to be instituted on Friday or Saturday.

20080828.0345.goes12.x.wv1km.07LGUSTAV.45kts-999mb-189N-740W.100pc.jpg
Gustav - Water Vapor satellite

Gustav's maximum sustained winds are only 45 mph and his central pressure is 999 mb. I think this is the weakest that we are going to see Gustav for a while as reintensification is expected tomorrow. The current forecast track brings Gustav right over the loop current, which should make for some interesting but stressful intensity fluctuations over the Gulf.


Gustav - Watches and Warnings

The model guidance is finally starting to converge upon a solution bringing Gustav into the Louisiana area early next week. However, intensity estimates are a joke at this time. After watching the model performance and looking at previous cases, the GFDL model seems to be the one of choice at this time.

My best guess for a landfall intensity is to predict a Category 3 hurricane. Please understand that this remains only a guess! Dynamical models do not handle intensity predictions well at all. It seems likely that given the time Gustav has to develop, he will be a very broad storm upon landfall. This should somewhat serve to limit his upper intensity, but also cause him to impact a very wide area. This is a typical result of a storm that has previously impacted an upstream landmass before a second landfall.

Click for full size model imagery:

Gustav - Track Forecast

Gustav - Wind Speed Forecast

Posted by Bryan Woods | Permalink

Tropical Storm Fay now crossing Cuba

Tropical Storm Fay is currently crossing over Cuba on her way to Florida. Her convection is currently displaces from the mid-level circulation and she looks to be building to the east. The terrain of Cuba looks to be disrupting Fay's surface circulation and vertical development, even though she has managed to strengthen slightly. It is going to be hard to make any confident conclusions about Fay until she reemerges over water.

20080818.1345.goes12.x.ir1km.06LFAY.50kts-1002mb-232N-812W.100pc.jpg
Fay - Infrared satellite

The latest aircraft recon found Fay to have maximum sustained winds of 60 mph and a central pressure of 1002 mb. This is a slight strengthening from previous measurements and represents a moderate strength tropical storm. Given the recent displacement of convection, NHC has placed its forecast track on the right side of the guidance envelope. However, NHC looks to be playing it safe on this track and, in my opinion, is not forecasting a track far enough to the east.


Fay - Watches and Warnings

There is a large spread in the models forecast tracks, which introduces a lot of uncertainty into the forecast. Currently the entire coast of Florida is in danger. The large spread in the models combined with the angle of approach of the storm is making it very difficult to forecast a landfall point. At this point my best guess is for a landfall somewhere between Fort Myers and Naples on the Gulf Coast. While the east coast looks to be spared a direct landfall, I do expect Fay to cross over the peninsula after landfall.

Fay's intensity at landfall is also a big question. While there are no signs of pending rapid development, there is also nothing present that would preclude it, other than limited time. At this point my best guess is for a category 1 hurricane at landfall, but that is just really an attempt on my part to hedge my bets. Perhaps we will have a better idea once Fay is back over water and we can see what her vertical structure looks like.

Click for full size model imagery:

Fay - Track Forecast

Fay - Wind Speed Forecast

Posted by Bryan Woods | Permalink

Tropical Storm Fay headed toward Florida

I have receive many notes asking where I am during this crucial storm. For those that care, I have been at a conference and training workshop for the Vancouver 2010 olympic games. Fortunately I fly back to the states tomorrow but I may still be spotty for the next couple of days. Unfortunately, there is a tropical storm headed for the Gulf coast of Florida. Tropical Storm Fay is not incredibly organized at this time, but she has a very well defined broad circulation. However, her sustained winds are only 45 mph and her central pressure is high at 1005 mb. This does not make Fay a very strong storm, but her track toward Florida is worrisome.

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Edouard - Infrared satellite

Fay - Watches and Warnings

There is a large spread in the models beyond 48 hours. Currently the entire Gulf Coast of Florida is in danger. The angle at which Fay will approach the coast will serve to amplify forecast errors. Since the track is nearly parallel to the coast, a slight shift of the track to the east or west will result in a large displacement of the landfall point to the north or south respectively.

Click for full size model imagery:

Fay - Track Forecast

Fay - Wind Speed Forecast

The dynamical models do not handle hurricane intensities well, at all. The best guess for Fay's intensity at landfall is approximately a category 1 hurricane. However, this really is just a guess. We do very poorly with this kind of forecast. The breadth of Fay's circulation and proximity to land make me doubt the Fay will rapidly intensify. However, Fay's track increases the threat of this storm simply due to the sheer area that will have to be warned and since Fay could impact an elongated section of the Florida coast. When Hurricane Charley took a similar track to that forecast for Fay, he intensified very rapidly to a category 4 hurricane and took southwest Florida 'by surprise' since the local were expecting a landfall in Tampa. All those on the west coast of Florida should continue to monitor the storm. Oh, and ignore that skinny black line inside the cone!


Posted by Bryan Woods | Permalink

Edouard makes landfall along Texas coast

Edouard has now made landfall along the upper Texas coast at the McFaddin National Wildlife Refuge. Edouard never did make it to hurricane intensity and came ashore as a strong tropical storm with maximum sustained winds of 65 mph.

20080805.1345.goes12.x.ir1km.05LEDOUARD.55kts-996mb-296N-942W.100pc.jpg
Edouard - Infrared satellite

Edouard - Watches and Warnings

The largest threat now from Edouard is inland flooding. There is currently some very heavy rain over the Houston area. Fortunately the rain in moving quickly at 14 mph so it won't add up too much. It looks like Edouard will slowly continue to weaken and bring beneficial rains to agricultural areas of Texas in the short term.

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Radar loop

Cheers,
Bryan Woods


Posted by Bryan Woods | Permalink