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Danny weakens; not likely to become a hurricane

By: Dr. Jeff Masters, 7:39 PM GMT on August 27, 2009

Tropical Storm Danny has weakened. Data from the Hurricane Hunters between 2 - 3 pm EDT showed top winds of just 40 - 45 mph at the surface. Satellite intensity estimates of Danny's strength have also declined since this morning. Danny's satellite appearance is pretty unconventional, and the storm doesn't look much like a tropical cyclone. The low level circulation center is exposed to view, with the heaviest thunderstorms lying several hundred miles east of the center. The center has remained nearly stationary the past four hours, and has grown less distinct. It is possible that a new center will form up to 100 miles to the east, in the region with the heaviest thunderstorm activity. Danny has already undergone several center relocations over the past 12 hours.


Figure 1. Afternoon satellite image at 3:17 pm EDT of Danny, showing the exposed swirl of clouds where Danny's center is, well displaced from the heaviest thunderstorm activity to the east.

The forecast for Danny
There's not much new to report from the latest set of 12Z model runs for Danny. The models have pretty much maintained their previous forecast, calling for Danny to intensify to a Category 1 hurricane by Saturday morning, and pass close to both Cape Hatteras, NC, and Cape Cod, MA. Given that the models did not correctly forecast Danny's current struggles, I believe it is unlikely that Danny will attain hurricane strength. Dry air from the upper-level low that has been keeping Danny disorganized continues to be a problem for the storm, despite the presence of moderate wind shear of 10 - 15 knots. Danny only has about 24 hours of relatively favorable wind shear left, and that is probably not enough time to intensify into a hurricane. By Friday night, a trough of low pressure will approach the U.S. East Coast and bring high wind shear of 20 - 35 knots. Danny will be close enough to this trough that the trough may be able to feed energy to Danny as the trough converts Danny to an extratropical storm. As a result, Danny may not weaken only slowly. A landfall in Cape Cod, eastern Maine, or Nova Scotia as a tropical storm with 45 - 55 mph winds is a reasonable forecast.


Figure 3. Tropical wave 94L off the coast of Africa.

Invest 94L off the coast of Africa
A well-organized tropical wave (94L) lies a few hundred miles southwest of the Cape Verdes Islands, near the coast of Africa. This disturbance continues to look more organized on satellite imagery. Shear is low, about 10 knots, and waters are warm enough to support continued development. The dry Saharan Air Layer is relatively limited in extent and intensity, so dry air may have only a small inhibiting effect on the wave. Expect continued development of this wave as it moves westward over the next few days. NHC is giving this system a medium (30 - 50% chance) of developing into a tropical depression by Saturday. This system is moving rather slowly, 10 - 15 mph. The GFDL and HWRF models both predict 94L will be a Category 1 hurricane five days from now. These models also predict that 94L will take a significant northward jog 3 - 5 days from now, in response to a strong trough of low pressure passing to the north (this is the same trough of low pressure that will be recurving Danny out to sea).

I'll have an update Friday morning.

Jeff Masters

Hurricane

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

Reader Comments

Why do you think it will not turn to NW, Ike, and shift to left, stoormfury?
1502. IKE
Quoting 69Viking:


I agree! They say the trough getting ready to exit the U.S. this weekend is going to turn it NW but I think it's too far South to feel the effects of that trough much.


Plus, that trough hasn't even made it through us here in the Florida panhandle yet. How is that trough going to influence 94L...3,000 miles away...this weekend?
Quoting GBlet:
I don't know who farted yesterday, but Oklahoma reported several small earthquakes!


Darn my post got eaten. We've had a brief spell of earthquakes here in Richmond Va. All of them happened in the wee early hours of the morning and I was asleep. Even if I was awake I couldn't feel it because all of them happened on the northside.
1504. FLdewey
Quoting slavp:
Hope he doesn't go in there blindlessly


That was the word... DANG I couldn't remember it! Okay so maybe he'll blindlessly anger 150% of the meteorologists in the building.
Quoting fredmc:
Does anyone feel that weather warfare is being used to divert all of the tropical storms, and hurricanes away from Florida? Is there anyone knowledgeable on this subject, does it even exist, or is it just hype?


I answered a question about this yesterday. The History Channel had a show called "That's Impossible" on Weather Manipulation and warfare and it seems its more possible than impossible. Also there is HAARP (google it) which could cause changes in weather patterns, so is it possible, yes, is it happening? We will never know, because The Powers That Be will never admit to it, because bigger issues and questions will arise when an area gets devastated.
look at the new CRAZY computer models THERE LOOK FUNNY TO ME.
Quoting jasoniscoolman10:
look at the new CRAZY computer models THERE LOOK FUNNY TO ME.


They don't look funny to me.
Quoting NdcisivProcrastn8r:
Morning all, been a while since I've posted. This is my 3rd tropical season here.

I got laid off from a Biloxi casino a year ago and relocated to Lafayette, La., and now using sonar for underwater surveying!

Anyway, been thinking for years and now finally did some preliminary research and see MS State has a mostly online BS program............point is.....any advice for me in wanting to pursue my childhood dream of a career in meteorology!?!

Thanks!


MS state is more a broadcast meteorology program, its good if you plan on going to pursue a career in broadcast meteorology, otherwise I suggest a bigger University for more of the science Meteorology all depends on what you want to do. I suggest going for the science part, because they have been really cutting a lot of broadcast meteorology jobs considering budget cuts. If you plan on doing the science part go for a masters or PHD, because a BS will barely cut it.
Why do the models have 94L turning out to sea.
1510. P451
Quoting IKE:
From looking at the naked-swirl known as Danny, I bet the NHC wishes it never existed.

The most pathetic looking TS I've about ever seen.


Watch them up it back to 60mph based on "an increasingly well defined circulation" like they did yesterday at 11am and extend TS warnings up to Delaware. :/


does anyone have any info on el nino? it looks to me on the sst map that the waters right off South American are cooling off.
1512. P451
Quoting tropicfreak:
Why do the models have 94L turning out to sea.


Because models never really do well with an invest. You need to have a strong and well organized low pressure system that has had several model runs done on it before you can trust them.

Quoting mobilegirl81:
I'll probably catch fire for this, but 94L's latitude, strength, speed and direction alone are going to put it into the Carribean sea. The models are flip flopping, they will go west again on the next run.
You have WU mail!

Quoting NdcisivProcrastn8r:
Morning all, been a while since I've posted. This is my 3rd tropical season here.

I got laid off from a Biloxi casino a year ago and relocated to Lafayette, La., and now using sonar for underwater surveying!

Anyway, been thinking for years and now finally did some preliminary research and see MS State has a mostly online BS program............point is.....any advice for me in wanting to pursue my childhood dream of a career in meteorology!?!

Thanks!
Quoting P451:


Because models never really do well with an invest. You need to have a strong and well organized low pressure system that has had several model runs done on it before you can trust them.



Thanks. Looks to be a Carribean storm, and possibly a Gulf coast storm or an east coast FL storm. Too far out to tell.
Quoting jasoniscoolman10:
look at the new CRAZY computer models THERE LOOK FUNNY TO ME.
Love the nogaps (I think that is what the black line is)
Yesterday for awhile it looked like a 'Z', and all I could think of was "Z' for Zorro"
Let's hope it is not a predictor - it would lead us on a merry chase. - Yikes!
1517. IKE
Quoting floodaintcovered:
Why do you think it will not turn to NW, Ike, and shift to left, stoormfury?


All it is is a weak low pressure system. They usually move west in the EATL. Plus, the experts at the NHC say..."ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR FURTHER DEVELOPMENT OF THIS SYSTEM OVER THE NEXT
COUPLE OF DAYS AS IT MOVES GENERALLY WESTWARD AT AROUND 15 MPH.

I see a ULL near 30N and 45W on visible, but it appears to be having no influence on 94L. The ULL appears to be drifting north, slowly.
1518. bwat
Quoting P451:


Watch them up it back to 60mph based on "an increasingly well defined circulation" like they did yesterday at 11am and extend TS warnings up to Delaware. :/


Down right horrible looking. The Coc keeps pulling farther away from the heaviest of convection to its east. As long as it stays like this, i wouldnt mind it landfalling over us. It would be interesting to observe.
06/25/09:


07/27/09:


08/27/09:


i'm not exactly sure i'd call it "cooling"...
Quoting tropicfreak:


Thanks. Looks to be a Carribean storm, and possibly a Gulf coast storm or an east coast FL storm. Too far out to tell.
you forgot "or mabey a recurve or dissipate." Might as well hit all the bases.

/s
Quoting IKE:
94L is booking it, generally west.........


Hey Ike,
how fast is it travelling?
ITS NOT MOVING AT 15 MPH IS MOVING AT 23 MPH..
Quoting NdcisivProcrastn8r:
Morning all, been a while since I've posted. This is my 3rd tropical season here.

I got laid off from a Biloxi casino a year ago and relocated to Lafayette, La., and now using sonar for underwater surveying!

Anyway, been thinking for years and now finally did some preliminary research and see MS State has a mostly online BS program............point is.....any advice for me in wanting to pursue my childhood dream of a career in meteorology!?!

Thanks!


Good Morning Everyone!

Indecisive Procrastinator huh? Kinda sounds like me at times...

At any rate, if weather is truly something you love, you will probably find success and happiness in making it a career.

That being said, what kind of meterology work do you see yourself doing? Do you want to be on TV? Would doing research be more interesting to you? What about using weather information to inform businesses how to be more efficient? Or you could try the Navy meteorology program and get excellent training after school... There is the National Weather Service, or a lot of smaller private weather firms.

My point is, think about what you see yourself doing with a degree. Then go out and investigate! Take tours, talk to people in the field, and try to figure out what you would be best at/ what you would enjoy the most!
1524. IKE
Quoting hurricanehanna:


Hey Ike,
how fast is it travelling?


NHC says 15 mph.
Some please verify here: I make the center of 94L to be 10N and 36.5W...

Anyone agree?
1526. A4Guy
Quoting tropicfreak:


Thanks. Looks to be a Carribean storm, and possibly a Gulf coast storm or an east coast FL storm. Too far out to tell.


it's not even a storm yet..and no certainty it will be...so why call it a "gulf storm" or "Caribbean storm" or "FL storm"? It can go anywhere from Nicaragua to Maine..or maybe even run aground in South America.
Quoting pearlandaggie:
06/25/09:


07/27/09:


08/27/09:


Looks like the prior disturbances have cooled the water off a bit...wonder if 94L will strenghthen slower because of this.
Latitude, strength, and speed reminds you alot of Ivan even though its not, it could be similar.
i just know its gonna be a labor day storm in fl and gonna mess up my fsu/miami game. all seriousness now i dont have a good feeling about this one at all. why do the models have it skipping through the central atl so fast? didnt frances stair step into fl?
Quoting P451:
Rather odd recon for Danny this morning.



Probing the trough and it's potential steering ability?

Can't think of anything else going on there...seems odd to me.



I haven't 'probed a trough' since Woodstock.

Quoting IKE:


NHC says 15 mph.

Thanks - I missed that
Thanks, Ike. I find your posts to be informative and always lacking any "wish-casting," pardon the term.


Quoting BobinTampa:



I haven't 'probed a trough' since Woodstock.



ha i see
1535. Prgal
New blog
Quoting hurricanehanna:


Looks like the prior disturbances have cooled the water off a bit...wonder if 94L will strenghthen slower because of this.


yeah, Bill's cold wake could have a negative effect on 94L's development, depending on path. i posted this yesterday or the day before....
1537. P451
Quoting BobinTampa:



I haven't 'probed a trough' since Woodstock.



HAHAHAHA
Quoting floodaintcovered:
Thanks, Ike. I find your posts to be informative and always lacking any "wish-casting," pardon the term.



Wishcasting - speculation? Nothing true but not totally false more like a theory.
1540. MahFL
Is Danny heading west again ?
1541. BGMom
Quoting BobinTampa:



I haven't 'probed a trough' since Woodstock.



Now THAT was funny!

You can now see the showers imbeded in the low COC
1543. hydrus
Quoting hydrus:
It means at this time of year that the farther south it goes- it can increase the threat to the Lesser Antilles. It can also be to far south were the conservation of angular momentum is not sufficient enough to give the system the spin it needs to become a tropical cyclone. But 10 degrees is enough to get her going. Water temperatures are usually warmer down there too.
Blog has slowed down today...
Looks like Blog Died. (starts CPR)
1546. juniort
About 94l a metoerologist who reports from Miami on local radio here said in no uncertain terms that it WILL turn north out to sea on not get close to the caribbean at all