TD 13 intensifying; Katia may pass uncomfortably close to U.S.

By: Dr. Jeff Masters , 3:28 PM GMT on September 02, 2011

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Tropical Depression Thirteen formed last night over the Northern Gulf of Mexico and is slowly intensifying, but isn't in a hurry to go anywhere. What TD 13 will do is dump torrential rains along the northern Gulf Coast over the next three or more days. So far, rain amounts along the coast have mostly been below one inch. At New Orleans Lakefront Airport, just 0.32" inches of rain had fallen from TD 13 as of 10 am CDT. Some coastal regions have received up to two inches, according to radar rainfall estimates. TD 13 is generating a large area of 30 - 35 mph winds over the Gulf of Mexico. At 7:20 am CDT, winds at the Mississippi Canyon 711 oil rig were southeast at 47 mph. This is above tropical storm force, but the wind instrument was 348 feet (106 m) above the ocean surface, and winds near the surface were probably considerably lower, near 35 mph. Latest surface wind observations from an Air Force hurricane hunter aircraft support leaving TD 13 as a tropical depression. Long range radar out of Mobile, Alabama shows heavy rain showers building along the northern Gulf Coast, but these rain showers are not well-organized into spiral bands. Strong upper-level winds out of the west-northwest are creating a moderate 10 - 20 knots of wind shear over TD 13, keeping the storm's heavy thunderstorms disorganized and pushed to the east side of the storm. However, latest satelllite loops show TD 13 is becoming increasingly organized, with a respectable spiral band forming on the southeast side, and an increase and areal coverage of heavy thunderstorm activity. This is very likely to be a tropical storm later today.


Figure 1. Radar-estimated rainfall from TD 13 from the New Orleans radar.


Figure 2. U.S. drought conditions on August 30. The rains from TD 13 have the potential to bring major drought relief to drought-stricken portions of the coast. Note how Eastern North Carolina is no longer in drought, thanks to the rains from Hurricane Irene. These rains also came close to putting out a persistent fire that had been burning in the Great Dismal Swamp near the Virginia/North Carolina border. Image Credit: U.S. Drought Monitor.

Forecast for TD 13
TD 13's large size, ill-formed circulation center, and the presence of dry air on its west side due to an upper-level trough of low pressure argue against rapid intensification of the storm for the next three days. Also tending to slow intensification will be the slow movement of the storm, which will allow cold water from the depths to rise to the surface, thanks to wind and wave action. Tropical cyclones strongly cool the water's surface when they pass over it, as seen in the time vs. depth chart of sea surface temperatures during Hurricane Irene's passage along the New Jersey coast (Figure 3.) However, the Gulf of Mexico has some very warm waters near TD 13 that extend to great depth (Figure 4), so the surface cooling imparted by TD 13 will be less than that seen for Hurricane Irene. As TD 13 moves closer to the coast, more and more of its circulation will be over land, which will also slow intensification. NHC's 11 am EDT wind probability forecast for TD 13 gave the storm a 23% chance of intensifying into a hurricane by Sunday. Assuming TD 13 does not attain hurricane strength, wind damage and storm surge damage will likely not be the main concern--fresh water flooding from heavy rains will be the most dangerous impact. Also of concern is the possibility of tornadoes. NOAA's Storm Prediction Center is currently not highlighting the Gulf Coast in their "slight risk" area for severe weather, due to the lack of enough solar heating to create instability. However, there will be plenty of wind shear in the lower part of the atmosphere that can potentially create spin in the coastal thunderstorms, and it is possible that as TD 13 intensifies, it may be able to generate several dozen tornadoes.

Coastal Louisiana, Mississippi, Alabama, and the extreme western Panhandle of Florida will likely receive very heavy flooding rains that will intensify Saturday and peak on Sunday. These rains should be able to put out the stubborn marsh fire east of New Orleans that has brought several days of air quality alerts to the city, but may cause moderate to severe flooding problems in other areas. The latest rainfall forecast from NOAA Hydrological Prediction Center shows that a large area of 15+ inches of rain is expected over Southeast Louisiana and coastal Mississippi. The region is under moderate drought, so flooding problems will be delayed compared to what we'd normally expect from heavy rains of over a foot. Flash flood watches are posted for New Orleans and surrounding areas, and rainfall amounts of 1 - 3 inches per hour are possible in some of the heavier rain squalls. Ocean temperatures are near record warmth, 88°F (31°C), which will provide plenty of moisture for heavy rains, and plenty of energy to help TD 13 strengthen into a strong tropical storm. Steering currents will be weak in the Gulf this weekend and early next week, which will likely make the motion of TD 13 erratic at times.


Figure 3. EPA, in conjunction with Rutgers University and the NJ Department of Environmental Protection, has an Autonomous Underwater Vehicle (AUV, aka the Glider) deployed off the coast of NJ (since early August) continuously monitoring ocean temperature, density, salinity, sound velocity and dissolved oxygen at different depths. The AUV's path and data are displayed at the following website: http://marine.rutgers.edu/cool/auvs/index.php?did =221&view=imagery. The plot of temperature versus time above shows that in the weeks prior to the arrival of Irene, the ocean was heavily stratified, with warm waters of 24 - 26°C (75 - 79°F, red colors) extending from the surface to a depth of 10 - 15 meters. A sharp thermocline existed at a depth of about 15 meters, and ocean temperatures were colder than 14°C (57°F, dark blue colors) below the thermocline. The strong winds and high wave action of Hurricane Irene on August 28 - 29 stirred up cold water from the depths to the surface, cooling the surface waters to 17 - 19°C (63 - 67°F). In the days since the hurricane, surface waters have begun to warm again. Thanks go to Kevin Kubik, Deputy Director of the Division of Environmental Science and Assessment for EPA Region 2, for making me aware of this data.


Figure 4. The total amount of heat energy in the ocean available to fuel a tropical cyclone, in kilojoules per square centimeter of surface area. Tropical cyclones that move over ocean areas with TCHP values in excess of 70 - 90 kJ/cm^2 commonly undergo rapid intensification. Waters that are warm to a great depth have the highest TCHP, and the Loop Current that brings warm water northwards from the Caribbean to the Gulf of Mexico usually has the highest TCHP values in the Atlantic. Currently, we have an eddy that broke off from the Loop Current earlier this summer, now located a few hundred miles south of the Louisiana coast, that also has high TCHP values. Image Credit: NOAA/AOML.

Hurricane Katia
Hurricane Katia is continuing its long trek across the Atlantic Ocean today, and will not pose a danger to any land areas over the next five days. Katia is still struggling with dry air and moderate wind shear of 10 - 20 knots. Latest satellite loops show surface-based arc-shaped clouds racing to the southwest away from Katia's core, a sign that dry air is penetrating into Katia's thunderstorms and creating strong downdrafts that are robbing the storm of heat and moisture. Katia is over warm ocean waters of 28.5°C, and these waters will increase in temperature to 29°C over the next five days. Katia will pass well north of the region of cooler waters stirred up by the passage of Hurricane Irene last week.

The models are split on when the upper-level trough of low pressure bringing the wind shear to Katia will move away, and the storm may spend two more days battling wind shear and dry air before the upper-level trough pulls away to the north and allows Katia to intensify more readily. It is still unclear how much of a threat Katia may pose to the U.S., but it is becoming increasingly clear that Katia will pass uncomfortably close to the U.S. East Coast. The trough of low pressure currently steering Katia to the northwest will lift out early next week, and a ridge of high pressure is expected to build in, forcing Katia more to the west. This decreases the danger to Bermuda, but increases the danger to the U.S. A second trough of low pressure is expected to begin affecting Katia by the middle of next week, and will potentially recurve the storm out to sea before it hits the U.S. However, the models differ widely on the strength and timing of this trough. Meteorologist Grant Elliot of Australia's Bureau of Meteorology in Perth pointed out to me yesterday that the long-range forecast for Katia has more than the usual amount of uncertainty, due to the inability of the computer models to agree on what will happen to Tropical Storm Talas in the Western Pacific. Talas is expected to hit Japan early on Saturday as a strong tropical storm, then race northwestwards into the Bering Sea off the coast of Alaska. Talas is then expected to transition into a powerful extratropical storm in the waters south of Alaska. This storm will create a ripple effect downstream in the jet stream, all the way to North America, by early next week. The timing and amplitude of the trough of low pressure off the U.S. East Coast expected to potentially recurve Katia out to sea next week is highly dependent upon the strength of Tropical Storm Talas during its transition to an extratropical storm. The computer models are not very good at handling these sorts of transitions, leading to more than the usual amount of uncertainty in the long-range outlook for Katia. It will probably be another 2 - 3 days before the models will begin to converge on a solution for the long-term fate of Katia. Dr. Bob Hart's Historical Tropical Cyclone Probability web page suggests shows that tropical storms in Katia's current position have a 17% chance of hitting North Carolina, a 21% chance of hitting Canada, a 13% chance of hitting New England, and a 55% chance of never hitting land. One almost certain impact of Katia on the U.S. will be large waves. Long period swells from Katia will begin affecting the Bahamas on Sunday night, then reach the Southeast U.S. by Monday morning. By Tuesday morning, the entire U.S. East Coast will see high surf from Katia, and these waves will increase in size and power as the storm grows closer. Given the slow movement of Katia as it approaches the coast, plus its expected Category 1 to 3 strength as it approaches, the storm will probably cause extensive beach erosion and dangerous rip tides for many days.

94L
A well-organized low pressure system with a surface circulation but limited heavy thunderstorm activity due to high wind shear is 450 miles south of Halifax, Canada. This disturbance, (94L), is headed northeast out to sea, and is being given a 60% chance of developing into a tropical depression by NHC. 94L is under a high 25 - 30 knots of wind shear, but this shear is expected to fall to the moderate range, 10 - 20 knots, by Saturday morning. However, sea surface temperature will fall from 27°C today to 25°C Saturday morning underneath 94L, and the storm will have a very short window of time to get organized enough to get a name. At this point, it's really a subjective judgement call on whether or not 94L is already a tropical storm.


Figure 5. A Portlight volunteer works to clear storm debris from Hurricane Irene in Hollywood, Maryland.

Portlight disaster relief effort in Maryland
Hurricane Irene heavily damaged the town of Hollywood, Maryland, when a tornado cut off electric power, water, and phone service. Portlight and Team Rubicon volunteers arrived before emergency personnel, after following up on a local tip. What they found was an isolated area whose plight was unknown to the larger community. Most residents were trapped at their homes by heavy debris. Portlight and Team Rubicon worked for two days to clear paths to each address, extract vehicles from debris, and cut down trees that constituted safety hazards. Portlight also instructed local residents how to operate and maintain chainsaws and safely clear debris. No other volunteer organizations or emergency personnel arrived at any time, and Portlight succeeded in meeting the specific needs of the underserved, unserved, and forgotten. Visit the Portlight blog to learn more; donations are always welcome.

I'll have a new post each morning over the coming holiday weekend; wunderground meteorologists Angela Fritz, Rob Carver, and Shaun Tanner will be handling the afternoon and evening posts. Have a great holiday weekend, everyone!

Jeff Masters

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Quoting Grothar:


Stationed in Fort Riley, KS and Fort Sill. Was in Manhattan KS in June 1966 for a big one. I am familiar with the expletives.


Wow, you have traveled a bit!

Unfortunately did not pick a good time to introduce myself . . . back to work. I don't comment much, as i feel I don't possess the knowledge to pass on any useful info, other than what is already being said . . . but will keep reading and occasionally say hello.

Nice to meet you . . . keep up the good work!
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Quoting Grothar:


Stationed in Fort Riley, KS and Fort Sill. Was in Manhattan KS in June 1966 for a big one. I am familiar with the expletives.


Were the expletives in old english?
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Quoting Grothar:


Stationed in Fort Riley, KS and Fort Sill. Was in Manhattan KS in June 1966 for a big one. I am familiar with the expletives.
KSU WILDCATS!!!!
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Storm Relative 1km Geostationary Visible Imagery
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T.C.F.W.
012/H/K/C1
MARK
17.85N/54.25W


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The track that the NHC has righ now, has the Miss. Coast and Al. Gulf Coast and inland under the gun.
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Quoting 996tt:


Most places have a canellation policy and have already taken deposits. Don't think Florida will get hurt too bad.


Yeah given this relatively late development; I was half asleep when I left home this morning but I thought I heard my Wife mention that she made reservations at a Hotel in Destin this weekend yesterday (She is the boss)......I would still go but remind folks on the Gulf Coast to NOT threaten their lives (or the lives of the little ones) by playing around in the rough surf as we lost two folks that way in Florida with Irene.
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Quoting WaterWitch11:
dang my head already hurts.... now i have to try and translate another taz.


Why bother with #7...waste of space.
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Loop-O-Doom

TD-13 Floater - Rainbow Color Infrared Loop
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dang my head already hurts.... now i have to try and translate another taz.
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5 cases of Fresca should be good.

Have to check the SC Stock though.
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Quoting InTheCone:


That's because I installed a 20k watt generator after Wilma, best shield ever!!!

I knew if spent all that $$ a storm would stay away - just look what it did to Irene - LOL!

Just hope it keeps working!


Yup, that is my theory too. We installed our whole house generator after Wilma also. After 10 days with no water or power from Charley and Wilma we went ahead and spent the money. So far no more storms for South Florida!
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Price gouging law in effect, Caldwell says
Published: Friday, September 02, 2011, 10:38 AM


BATON ROUGE -- Gov. Bobby Jindal's emergency declaration as the tropical depression nears the Louisiana coast has triggered the state's price gouging law, Attorney General Buddy Caldwell said on Friday.


Caldwell said merchants cannot sharply raise the price of retail products, gasoline, hotel rooms and other goods and services unless the prices they have to pay are suddenly raised.

Civil and criminal penalties apply, he said.
Caldwell said suspected instances of price gouging can be reported to the attorney general's office at 800-351-4889.
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Quoting daddyjames:


Grew up in Plantation, just west of the turnpike. Folks still live in the same house. Currently, Oklahoma. We have a different kind of storm here . . . lol. No fancy names just expletives

;)


Stationed in Fort Riley, KS and Fort Sill. Was in Manhattan KS in June 1966 for a big one. I am familiar with the expletives.
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Quoting LightningCharmer:
Most insurance companies that I've with which I've dealt will not let you bind a policy during a named storm, at least that's for south Florida.

Having worked in the insuracne business for the last 19 years I can say that all insurance companies do things a little differently. Most companies that write business in coastal areas have a "wind deductible" which is generally a percentage of what your house is insured for. What is "wind" is where you see some variation in coverage. Some companies consider a "named storm" to be a wind issue and impose the wind deductable whereas other companies don't consider it a wind event until it's a hurricane. Binding authority varies as well. Some companies will stop writing business when their area falls under a storm watch or warning whereas other wait until the storm hits a predetermined long/lat line. The company I work for will allows to to bind coverage under a watch but not a warning. If you have question call your agent before a storm hits because you don't want to assume you have a certain coverage and find out later you don't have it.
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i know i know but..if ur talking about the coastline and take out NC..lee will be much more of a threat and produce more winds then irene did
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Quoting jpsb:

A Connie that doesn't like males? hmmmmm, well a hit to S. Fla from katia seems very unlikely at this time. hard to imagine the B.H. building back strong enough to send hurricane Katia into S. Fla. Now a weak TS Katia might be able to avoid the north turn a strong hurricane katia not so much.


This is what I was thinking and I'm not a weather person... see, I'm learning something!! Thank you for answering me... I didn't mean to pick on males...it's just some people were being rather rude...they could have just put me on ignor, instead of insulting me and hurting my feelings (ok, maybe not really hurting my feelings.lol.)
Member Since: September 1, 2008 Posts: 0 Comments: 672
210. 996tt
Quoting weathermanwannabe:
TD 13 is already an economic tragedy for many hotels and vendors along the Northern Gulf Coast hoping for much needed traffic and business this weekend cause many folks might be cancelling their weekend beach plans in the region.


Most places have a canellation policy and have already taken deposits. Don't think Florida will get hurt too bad.
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I hope the Big Easy have got them pumps in good working order,they will be getting a good workout no doubt!
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Still set on getting an inch or two from the West side of the system. From the latest shear maps posted, it looks like this could still happen for us.

Tremendous rains for LA/MS though. That is a Drought Buster!
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TD 13 is already an economic tragedy for many hotels and vendors along the Northern Gulf Coast hoping for much needed traffic and business this weekend cause many folks might be cancelling their weekend beach plans in the region.
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Quoting InTheCone:



I actually use this blog to make long term decisions about preps. I have animals and I live in an evac. zone and if I waited for the NHC to get moving I might not be able to get a pet friendly hotel reservation out of the area. I make the reservations just in case and then cancel them if the threat passes. I just did this for Irene and this works quite well if you learn how to filter through the material.

Also, in defense of Connie, some people become quite anxious about these storms and like some reassurance from others. Yes, it does become quite tiresome as a storm approaches an area, but you get used to it or bail out.


Also agreed. I have two dogs, two cats, a wife and a three year old daughter I have to worry about.
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202. 996tt
Quoting PcolaDan:
Surf not too bad yet.



Choppy waist high in Destin. Giving it a go here soon.
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Quoting rmbjoe1954:


That is also possible, Taz.

Please note that Tazmanian7 is not the real Taz.
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Quoting lhwhelk:

BOTH of them? TWO storms?
Open Google News Top Stories, it's the lead story, and still has it listed that way.
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Quoting hunkerdown:
that has her moving NW now and for the next 5 days or so...hmmm, circular file


Doesn't look good for now, does it?
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Thanks MississippiWX. Guess I need to make sure all my pets have a safe and dry place. At least my brown grass will be green again. Is there any possibility for this storm to make a sharp left turn and go into TX.? Oh I hope they get some much needed rain soon.
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For anyone that wants to learn,this blog can be exellent,there are several very knowledgeable people on here who can teach you a lot,then there others you just ignore.You find out quickly who is who
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Quoting NJcat3cane:
Taz..y the new handle after so many post with the old one
Fake Taz...up to #7 now
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Quoting connie1976:


Exactly.... I have learned a lot here.. It's fun.. :)


I have actually learned a good bit from just reading some of the post and looking at the images. This is a very informative site that is why I come here. If I just wanted to find out where it was going I could easily read on one of the local news sites. I prefer to learn as well.
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Quoting hunkerdown:
if you were able to see most of her posts on this blog, they deal with a system east of Florida asking will it effect me. Yes, I agree it gets old and redundant. Best advice, do NOT come on this blog, go directly to the NHC...in all reality, who cares what a bunch of bloggers, the majority not old enough to drive, THINK or will say based on what they WISH. I would certainly not bet my money or make my preparations based on it.



I actually use this blog to make long term decisions about preps. I have animals and I live in an evac. zone and if I waited for the NHC to get moving I might not be able to get a pet friendly hotel reservation out of the area. I make the reservations just in case and then cancel them if the threat passes. I just did this for Irene and this works quite well if you learn how to filter through the material.

Also, in defense of Connie, some people become quite anxious about these storms and like some reassurance from others. Yes, it does become quite tiresome as a storm approaches an area, but you get used to it or bail out.
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I stood outside to take a look out East to see if I could find a cloud even associated with TD 13. All I got was a gust of wind.

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190. jpsb
Quoting connie1976:


I don't rely on the bloggers here....I just like to get some opinions.....I have every right to....dang, there are a lot of pmsing people here...and sadly most of them are males!

A Connie that doesn't like males? hmmmmm, well a hit to S. Fla from katia seems very unlikely at this time. hard to imagine the B.H. building back strong enough to send hurricane Katia into S. Fla. Now a weak TS Katia might be able to avoid the north turn a strong hurricane katia not so much.
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Surf not too bad yet.

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Quoting atmoaggie:
Not too late to get a 2 TB external and clonezilla important partitions...that could be done in a hour or two, especially without the fsck.
Just saw 2TB on sale for $70. Can't remember where. Clonezilla's free. Good Advice.
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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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