Aug 31, 2011

DAY 91

TD#12 has evolved into Tropical Storm Katia today. She is only at 38W, and is already a very organized tropical system. Katia is forecast to become a hurricane tomorrow and then a major hurricane by the weekend.

(Tropical Storm Katia)

There is a very strong computer model consensus that is pulling Katia on a more northward heading for the rest of the week. There are 2 reasons for this. The Subtropical Ridge has recessed far to the north and another trough sweep is forecast to move off the US coast. There is a very good chance that Katia only effects Bermuda.

Just like always though, the forecast error is fairly large that far in advance. This track could change in either direction as the week goes on. The UKMET and the Navy's NOGAPS model are forecasting a bit of a more southward track. It should be noted however that these models have not performed as well as the other models. The NOGAPS model has Katia scraping by the Virgin Islands in 5 days.

(NOGAPS run on Katia)

The National Hurricane Center has also circled an area in the Caribbean, in today's Tropical Weather Outlook. This area has become very wet and active recently. There is a tropical wave inside that yellow circle that is moving into an area that the monsoon trough has been working all season, and there is also an area of mid to upper level vorticity that was a piece that split away from a front that passed through Florida a couple of days ago. This area will linger and fester for several days. The GFS and the European model are developing this into a tropical system as it moves into the Gulf. This area will be in a race with the next African wave to become the "L" storm Lee.

(Possible Invest Area)

Aug 30, 2011

DAY 90

Irene is now gone, but the US coastline is still dealing with flooding problems from North Carolina, all the way up to Vermont. Jose was a short lived storm that had no impact on land. So now we are left with Tropical Depression #12. It formed this morning and is on the verge of becoming Tropical Storm Katia.

(Tropical Depression #12)

It's got to be a little unnerving for Outer Banks residents to have another tropical system pointed right at them. This system is forecast to move across the Atlantic to the WNW and then take a turn to the north. There is a strong model concensus on this guidance. One thing to note about TD #12 is it's very low latitude. It is located south of 10N right now, so even a WNW heading would take it pretty close to the Windward Islands.

There have been what seems to be an unusual amount of deep digging and frequent troughs being swept down from Canada this season. These will continue to protect the southeast from landfalls. It will take just the right timing for a tropical system to creep in and effect Florida, another sweeping coastal storm is a bit more likely with this set up.

The more tropical waves that get launched off of Africa, the better the probability of one of those waves sneaking into the lower latitudes. And the Saharan coast is loading up another wave. This one is also being developed by forecast models.

(Left: TD#12, Right: New African Wave)

Aug 28, 2011

DAY 89

Irene is now a 50 mph tropical storm moving through upstate New York and New England. It is forecast to remain a tropical or post-tropical storm all the way through Canada and out in to the cold north Atlantic where she will die. She made 2 more landfalls in the US, one New Jersey, and another on Long Island in New York.

(Tropical Storm Irene)
Much of the same is happening there as occurred in the south, just on a bit of a smaller scale. Inland flooding will be the story there just as it was down in North Carolina and Virginia. New York City is getting it's motor running again after completely shutting down as a precaution. You could play Monday morning quarterback after the fact and say that this was a waste. But that was the call that they made, and who knows what would have happened if they just went with voluntary evacuations. Let's just hope that this doesn't cause a distrust in forecasting. I myself have always been in the school of thought that you give the public the most accurate information possible and let them make decisions for themselves.

(Irene raises the East River in New York)
Elsewhere in the tropics there have been a few surprises that I haven't made an entry for yet. Tropical Depression #10 that was very close to becoming a tropical storm, fizzled out before it could become Jose. And then a swirl pops up in the central Atlantic near Bermuda and is immediately designated Tropical Storm Jose. He is forecast to continue moving north into cold waters and dissipate sometime tomorrow.

(Tropical Storm Jose)

There is also a strong tropical wave that has emerged from the coast of Africa. It has been designated Invest 92L and is being given a near 100% chance of becoming a tropical cyclone over the next 48 hours. It has a nice tight spiral evident from the satellite, that view comes at the expense of its convection being pushed away to the southwest.

(Invest 92L)

If this storm does get named, they will call it Katia. And if this happens before Wednesday, it will be the our 7th named storm in the month of August. That is the most August storms since we had 8 named storms in August of 2004. 92L is forecast to trek across the Atlantic on a WNW heading. It is not projected to effect any land masses at this point. But it is still way early on that thought.

DAY 88

Hurricane Irene made landfall at 7:30am eastern in Point Lookout, North Carolina as a Cat 1 with 85 mph sustained winds and a central pressure of 952 mb. She had an unusually large tropical storm force wind field, and her heavy rains brought substantial inland flooding to North Carolina all the way to New England. Irene did not cause heavy damage to infrastructure, but did cause widespread minor damage. The 10 to 15 foot breakers will leave considerable beach erosion.

(Hurricane Irene at Landfall)


I was surveying the storm up and down the Outer Banks of North Carolina throughout the storm. The thing that stood out to me the most was the huge and even distribution of tropical storm force winds. There where tropical storm force wind gusts recorded from the Cape all the way to Charlotte, which is more than 300 miles. I was at Nags Head at 7:30am when Irene made landfall and was experiencing 40 mph sustained winds there. As I made my way down the Cape on highway 12 as far as the road was open, I never registered a sustained wind above 60 mph, and I have my doubts that sustained winds ever reached more than 70 or 75 mph. There were no hurricane force sustained winds recorded at any official measuring station. Several storm chasers that I know and respect told me that they measured no hurricane force sustained winds at Atlantic Beach or Harkers Island. Even as the center of circulation passed over me when I worked my way back to inland Tyrrell county, the maximum sustained wind was only 60 mph. 

  (Raw Video of Irene in the Outer Banks)

Wind gusts however were a completely different story. Not only where they widespread like the NWS graphic shows below, but they were very frequent. I was getting a 70 mph plus wind gust about every 15 to 20 minutes. The Cedar Island Ferry Terminal recorded the highest gust at 115 mph, the Fort Macon Weatherflow Station near Atlantic Beach had a 92 mph gust, and the Billy Mitchell Airport in Hatteras recorded an 88 mph gust. 

Actual damage from the winds is relatively light. Some cosmetic damage to roofs is about all I saw, there was a lot of damage to the power lines in the area that I saw, but fortunately the repair will just require reconnection. So the unbelievable 2 million costumers without power in the US, will likely be reconnected within a couple of days. There were just a few areas were there was damage to the actual power poles themselves. These are the repairs that will require a little more attention.

 (Power Lines Damaged Near Nags Head)
                                   (Minor Roof Damage in Nags Head)                                   

The precipitation that I witnessed in North Carolina was very high. The most I've seen in a storm since Tropical Storm Fay which dumped more than 27 inches on rain on Melbourne, Florida. Early tally's from the National Weather Service has Bunyan in Washington County, North Carolina with the highest amount of 14 inches. If that stands as the high, I'll be a little surprised just because it felt like more than that. But that would come nowhere near Hurricane Floyd's 24 inches in 1999, which still stands as North Carolina's wettest storm of all-time. Flood damage could end up being one of the costliest part of this storm. 

1. BUNYAN                    14.00              
2. WASHINGTON            11.31              
3. NEW BERN                 11.13             
4. GRIFTON                   10.53             
5. NEWPORT-CROATAN  10.22              
6. WENONA                   10.13              

(Preliminary Rainfall Totals in NC from the NWS)


The National Weather Service in North Carolina reported 10 to 15 foot breakers there, 7 to 8 feet in Virginia, and 3 to 5 feet in the NYC area. There will no doubt be some damage to coastal homes as a result of this, although I did not witness any along the North Carolina coast. The surge did not reach high enough to effect most of the structures there because they are built to withstand the height of those surges, and I saw no spot where the surge was able to destroy any of the pillars that those homes are built on. The damage to the beaches is not assessed yet, but the damage there will likely be pretty significant. The surge did damage the ends of a couple of piers in NC, one was the historical Atlantic Beach pier in front of the Sheraton, and the Bogue Inlet fishing pier was also damaged. I shot a little video of the Nags Head fishing pier, and it's easy to see the power of the waves when they smash into it.

(Nags Head Fishing Pier During Irene)


Irene did spawn many tornadoes. Reports came in from North Carolina, Virginia, and Delaware.  They were small and short lived as many hurricane spawned tornadoes are. With a rotating storm coming in so low to the ground, it doesn't take much effort for a small twister to be triggered. A little friction from the land as the outer bands come ashore is usually all it takes. I came across some tornado damage on highway 64 just outside of Columbia, North Carolina. A modular home was completely destroyed, a few other nearby structures where damaged and a pickup truck was flipped.


(Tornado Damage near Columbia, NC)


13 deaths have been blamed on Irene so far. But the financial cost will likely take several months to tally. Hurricane Irene will likely go down in history as one of our nations most expensive storms. Factor in insurance claims for property damage, repair to infrastructure, and the restoration of beaches, and we could be looking at a 10 to 20 billion dollar storm. One thing to note with the infrastructure is that we were preparing ourselves for a much worse scenario. So the convoy upon convoy of utility linemen, and tree trimmers, and generator trucks that were deployed long before the storm hit, will factor in even if they are not needed or used. The men will be paid, and the fuel has been purchased.

Aug 27, 2011

DAY 87

Short entry tonight because I just drove 11 hours to Cape Hatteras, North Carolina. Hurricane Irene is forecast to make landfall just down the road from here in Ocracoke. The center of storm is visible on radar at this point. The eye-wall of Irene has fallen apart, with a wide opening on the southwest side where she took in a gulp of dry air earlier today. Each rain band that passes through my location in Nags Head gets a little stronger each time, but the hurricane force winds wont get here until the morning.

(Hurricane Irene on Radar)

Irene has weakened to a category 2 storm tonight, and it looks like it will be able to stay that strength until landfall tomorrow at about 8am eastern. Although the National Hurricane Center is forecasting Irene to weaken further to a Cat 1 at landfall. Her maximum sustained winds are 100 mph and her pressure is 951 mb. That is still a pretty low pressure, so one logical thought on that is that the energy for a strong Cat 2 or low Cat 3 is there, but with the massive size of Irene, all that energy is being dispersed greatly. If she is able to contract her size a little bit, which it looks like she is doing, she will be able to remain a Cat 2 a landfall.

(Hurricane Irene)

As for the rest of Irene's journey through the US coastline, she is still projected to reach New York City at hurricane strength. Given the dense population in her path, Irene could become one of the most costly hurricanes of all-time. Maybe even more expensive than Katrina in 2005, which most estimates have a about 100 billion dollars.

Aug 26, 2011

DAY 86

Hurricane Irene is now clear of the Bahamas and is once again beginning to strengthen. She is a Cat 3 storm with winds down a bit from last night at 115 mph but her central pressure is down to 942 mb. 

(Hurricane Irene)

With a heading of north now at 14 mph, Irene is expected to make landfall near Beafort, North Carolina on Saturday afternoon. If it is a daytime landfall, there will likely be some spectacular video shot by chasers. North Carolina is already seeing those upper-level outflow clouds from Irene, it won't be long before the first rain bands move through. It could end up being a 48 hour build up to land fall there.

(Hurricane Irene)

It looks like Irene is making one last attempt to become a category 4 storm. She's got a long way to go though, and the Hurricane Center is not forecasting that to happen. NHC's forecast is for Irene to still be a major hurricane just before landfall, and then weaken a bit at landfall to a Cat 2.

Then after Landfall, Irene is forecast to continue on across the Potomic, and into a pocket of our nations most dense population. In Irene's path is New Jersey, New York City, Providence, and Boston. She is still forecast to be at hurricane strength all the way through those zones. Coupled with the dense population, is the older construction of the buildings, and the hurricane inexperience of New Englanders. This is a straight up recipe for disaster. For comparison, look at Hurricane Charley in 2004. Charley was a Cat 1 hurricane when it hit Orlando in the middle of the state. It did widespread, and locally heavy damage. That is what Irene is forecast to be when it hits New York City, and they will have to deal with storm surge damage, Orlando obviously didn't have to deal with that.

(Hurricane Charley approaching Orlando in 2004)

Elsewhere in the tropics, Invest 90L has been upgraded and classified Tropical Depression #10. It is forecast to become Tropical Storm Jose tomorrow night, but is not forecast to be a threat to land. 

(Tropical Depression #10)

Aug 25, 2011

DAY 85

Hurricane Irene has become a large and powerful category 3 storm. She cut right through the central Bahamas today making a direct hit on several islands there. She has maximum sustained winds of 120 mph and a minimum central pressure of 952 mb. Her forward speed has picked back up today to 12 mph and she continues to track northwest.

(Hurricane Irene from NASA's Terra Satellite)
The Hurricane Center is forecasting Irene to start making a bit more of a northward movement sometime tomorrow. The official NHC forecast track has not changed since last night. Irene will continue to plow through the Bahamas, and then she is forecast to scrape the Outer Banks and then right into New England. The intensity forecast has change however, Irene is not forecast to be a Cat 2 hurricane when it encounters the North Carolina area. Before that happens, she does still have a very good chance of growing into a Cat 4 hurricane after clearing the Bahamas.

The computer models haven't changed either. A curious thing is happening over the continental US however. There is yet another trough being spun down from Canada, and it is moving very quickly towards the southern states. You can see it in the water vapor loop below crossing through the Ohio Valley. You can see that there is going to be a battle between that trough and Irene. So far this has not caused the forecast models to alter course.

The outer rain bands will begin to move across the Florida peninsula tomorrow. One band can be seen on radar as it moves through the northern part of the Bahamas.  Out in front of that there is a line of very light showers, those are actually bands from Irene as well, they just don't have a lot of moisture in them. Most of the bands will be able to stretch across the state delivering brief periods of rain and wind over the next couple of days.

Elsewhere in the tropics, Invest 90L is looking like it my soon become a tropical cyclone. It is located just southwest of the Cape Verde islands tonight, and the NHC is giving it a 70% chance of developing in the next 48 hours. For now, it is not forecast to effect any land areas. Invest 98L is still alive but just barely. NHC is now giving it a near 0% chance of developing in the next 48 hours.

(Invest 90L)

Aug 24, 2011

DAY 84

Hurricane Irene spent most of Tuesday as a downgraded Cat 1. That is where she's at tonight at 11pm eastern with maximum sustained winds of 90 mph and a pressure of 969 mb. That is a very low pressure for a storm that is only a Cat 1, but Irene has become a little lopsided today after battling a little dry air and some moderate wind shear. The most evident thing from the visible satellite is the wobble of Irene's center. A wobble from any spinning object is an indication that it is losing momentum. Or in Irene's case, struggling to regain it.

(Hurricane Irene)
Don't be fooled by her Cat 1 status though, Irene is still a strengthening hurricane. The eye-wall is starting to get its form back, as seen from the TRMM satellite using  85GHz microwave imagery. Also in this image you see the lopsided nature of her outer structure. The south and west quadrant is not symmetric with the other sides. Those Greater Antilles islands occupying that area is mostly to blame for that.

(Hurricane Irene from the TRMM Satellite)

The official forecast track from the National Hurricane Center has shifted to the east a bit tonight. Irene is in the exact spot that she was forecast to be 24 hours ago. The shift was made to the day 4 and 5 part of the track where it now has US landfall for Irene in the Outer Banks of North Carolina. Florida is now completely out of the 'cone of possibility' which significantly lowers the possibility of Irene making landfall in Florida.

The computer models have also shifted today. They have shifted into a consensus, agreeing with each other and agreeing with the official NHC track. Irene is also still forecast to become a major hurricane, and possibly a Cat 4 after clearing the Bahamas.

Invest 98L is still harmlessly out in the the central Atlantic. NHC is still giving it a 10% chance of developing into a tropical cyclone. It is forecast to continue WNW into the north Atlantic.

(Invest 98L)
A new tropical wave has emerged off of Africa and has been designated Invest 90L. It is located near the Cape Verde islands and is being given a 30% chance of developing in the next 48 hours.

Aug 23, 2011

DAY 83

The 9th time was the charm in the Atlantic. Irene became our first hurricane of the season this morning at about 5am eastern. She did so as she was making landfall in Puerto Rico. So technically the streak is over. It had been 1,072 days since the last landfalling hurricane in the US. And with Puerto Rico being a territory of the US, you could say that the streak has come to an end. The streak for the 'lower 48' will likely come to an end this weekend as Irene is forecast to make landfall along the Carolina coast.

(Hurricane Irene)

Irene left behind some damage in Puerto Rico as well as St. Croix and the Virgin Islands. The National Meteorological Service this afternoon was reporting 10 inches of rain in Naguabo and 7 inches in the island municipality of Vieques. out of Puerto Rico reported homes flooded, powerlines down, roads washed away by landslides, and about 800,000 Electric Power Authority customers without power. And it has continued to rain there all day since that report.

(Damage in Puerto Rico Courtesty
Hurricane Irene is growing bigger and growing stronger tonight. It is forecast to become a major hurricane at some point tomorrow. But tonight as of the 11pm advisory, Irene had maximum sustained winds of 100 mph and a pressure 980 mb. The Turks and Caicos Islands and the Bahamas are next to encounter Irene over the next 48 hours.

Where Irene might head after Wednesday night is still up for debate. Will she make a northward move towards the Carolina coastline or will she continue on her current heading and scrape right up against the Florida coast? The official forecast track from the Hurricane Center has been the most accurate tool over the past few years, and it is targeting the Carolina's on Saturday night. But please note that most of Florida does still remain in the cone of uncertainty. 

Some of our most reliable computer forecast models are still in some degree of disagreement tonight, which worries me and should worry anyone on the east coast.  The GFDL has moved slightly to the east throughout the day. And the HWRF just moved quite a bit to the west with this latest run. They are all in agreement with the next 48 hours, but after that, they are all over the board.

All of the models are forecasting a strong Sub-Tropical Ridge, or else they would be sending Irene out to sea. Even this sea-level pressure model from the Tropical Analysis and Forecast Branch shows a very strong ridge remaining in place, guiding Irene on more of a Savannah, Georgia track. One thing that the models do agree on is the intensity. They all agree that Irene will become a major hurricane.

Invest 98L is still out there, by the way. It is still not forecast to become a tropical cyclone.

(Invest 98L)

Aug 22, 2011

DAY 82

Irene is a hurricane in the making. Tropical Storm Irene has all the characteristics of a storm that is on the verge of strengthening to hurricane status. The convective bands are forming on all sides and are being pulled into Irene's center of circulation.

(Tropical Storm Irene Visible Satellite)

On the zoomed out shot, you can see a beautiful anti-cyclone has been established over top of Irene, spinning out those cirrus clouds clockwise. All the circulation, and ventilation has been set properly. Now the next step will be the formation of an eye-wall around the center.

(TS Irene Infrared)

It may not be able to set up that eye-wall and become a hurricane just yet though. It is just about to make landfall in Puerto Rico, and with the center of circulation over land, Irene's progress will be disrupted temporarily. The National Weather Service in eastern Puerto Rico is reporting heavy rain with 25 mph winds, gusting to 50 mph tonight at 11pm eastern. That Island should have no major problems with a weak storm like this, inland flooding and mudslides are the greatest threat. That threat will be far greater if Irene impacts Hispaniola.

(TS Irene Nearing Landfall in Puerto Rico)

Irene is headed slightly WNW at 15 mph. Her maximum sustained winds are 70 mph, and her pressure has fallen to 993 mb. She is not forecast to become a hurricane over the next 48 hours as she impacts Puerto Rico and the Dominican Republic. Although it is very possible for Irene to still strengthen as she moves through Puerto Rico. She has been gathering so much energy and momentum, that could push her over the threshold before the land interaction shuts off some of her fuel source.

After Irene's direct hit on Puerto Rico, she is expected to graze the northern coast of the Dominican Republic and Haiti tomorrow. Once she clears that, Irene will be free to strengthen into a hurricane before hitting Andros Island in the Bahamas and then into Florida. The NHC track has Irene as a hurricane off the coast of Port St. Lucie Thursday evening. And then making landfall as a Cat 1 hurricane in North Florida.

The computer forecast models show a completely different scenario. 3 models shown in the image above take Irene through the Bahamas and then into Charleston, South Carolina on Saturday. While the 2 other models keep Irene moving west after impact with Hispaniola. Given the fact that we don't know what impact the land interaction is going to have on Irene over the next 48 hours, I would say we can afford to wait and see with this one. For one, she won't be able to become bad hurricane over the next 2 days. And two, we will still have 48 hours to prepare after she is clear of  Hispaniola. The steering layer below does show a path up the eastern seaboard.

Elsewhere in the tropics, Tropical Depression Harvey is trying to make a comeback. He made landfall in Belize yesterday, cross the Mexican Yucatan and entered the Bay of Campeche. You can't quite make out the center of circulation in the visible satellite image from earlier today, but it is in the very south end of the bay, not under that cluster of convection over land. The National Hurricane Center is actually forecasting Harvey to regain his status as a tropical storm tomorrow morning just before making landfall again and then dissipating over Mexico.

Tropical Depression Harvey)

Also, Invest 98L is still listed with a 10% chance of development in NHC two day tropical outlook. Things are not looking so good for this Invest right now. It could still become one of those storms that get named out in the middle of nowhere and then quickly vanish. But it is more likely just to disappear straight away.