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Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.

New depression forming?

By: Dr. Jeff Masters, 1:05 PM GMT on September 03, 2006

A tropical wave near 13N 39W, midway between Africa and the Lesser Antilles Islands, appears to be developing into a tropical depression. This wave was declared "Invest 90L" last night by NHC. The wave has a pronounced spin, and plenty of heavy thunderstorm activity surrounding it. This activity is fragmented and not concentrated near the center of circulation, but it gradually getting better organized. At the current rate of organization, formation of a tropical depression seems likely by tonight or Monday morning.

Three of the major models--the GFS, UKMET, and GFDL--do develop this system into a strong tropical storm or Category 1 hurricane by six days from now. The system is moving west-northwest at 10-15 mph, and these models all indicate that the long-range path of the storm will be north of the Lesser Antilles Islands. The GFS predicts the storm will become a powerful hurricane that will recurve a few hundred miles off the U.S. East Coast without hitting land. Wind shear over the system is low, about 10 knots, and the wave is over warm SSTs of 83-86F (28.5-30 C). Wind shear is forecast to remain low over the next few days. A large area of dry air and African dust to the wave's north may be an inhibiting factor, but this is probably to far away at present to be a problem. The large area of thunderstorms about 400 miles west of 90L, formerly designated "Invest 98L", is being absorbed into 90L.


Figure 1. Preliminary model tracks for Invest 98L. These models are described at the NHC web site.

Lesser Antilles tropical wave
A small tropical wave surrounded by a cloud of African dust is moving through the eastern Caribbean this morning. This wave, which NHC has designated "Invest 99L", is tracking west at 15 mph and has a small area of heavy thunderstorms associated with it. A large upper trough of low pressure over Cuba and Hispaniola that is creating about 10-20 knots of shear over 99L, preventing significant development. The trough is expected to weaken and move west over the next few days, potentially creating a low shear environment over most of the Caribbean. This could allow intensification of 99L into a tropical depression by Tuesday at the earliest. NHC has not run any preliminary models for this storm since yesterday.

New wave coming off the coast of Africa
A strong new tropical wave is emerged from the coast of Africa yesterday and is just south of the Cape Verde Islands. The wave has pronounced spin, but the thunderstorm activity associated with it is very disorganized. The wave is under 10-20 knots of wind shear, and has some potential for slow development over the next few days.

Tropical Storm John
Hurricane John spared the most heavily populated areas of Mexico's Baja Peninsula significant damage when it came ashore Friday afternoon on the sparsely populated eastern side of the Peninsula as a Category 2 hurricane with 110 mph maximum winds. Many roads were washed out in the resort towns of Cabo San Lucas and San Jose del Cabo, and helicopter airdrops of food and water were needed for 6000 residents cut off by washed out roads near where the center made landfall. However, no one was killed by the storm. Radar from Guasave shows John is still moving up the Baja Peninsula, spreading heavy rains. John will continue to weaken as it moves northwest along the Baja Peninsula, and should die on Monday. Moisture from the hurricane will likely bring flooding rains to portions of the Southwest early next week.

Typhoon Ioke
Typhoon Ioke is now barely a major storm, with its top winds of 115 mph barely qualifying it as a Category 3. It is forecast to recurve to the north and miss Japan.

Lessons learned from Ernesto
Ernesto may be gone, but its rain, winds, and flood waters still linger over the Eastern U.S. Rain from the storm penetrated all the way to may home in Michigan yesterday, a sure indication of a storm with a major far-reaching impact. Let's summarize two important lessons from the storm:

Lesson 1: This is not the Hurricane Season of 2005! By this time last year, we were already up to the 13th named storm of the season, Maria. Pretty much anytime something could develop, it did, and it usually took the worst possible path. This year, we are only up to the 5th named storm, and the storms have been taking some fortuitous paths. Certainly, we got very lucky with Ernesto--I was convinced that Haiti was in for a major disaster with heavy loss of life, and Ernesto would get his name retired. Hurricane Jeanne (2004) and Hurricane Gordon (1994) were both about the same strength as Ernesto when they hit Haiti, and both storms killed thousands. Yet Ernesto only dumped 2-8 inches of rain on Haiti, an unusually low amount for a Category 1 hurricane. Ernesto also took the longest possible path over land, given its general track, cutting across the Florida Straits without spending much time over water. I'll be full of much less doom-and-gloom for the next storm of this season that threatens land. This is not the Hurricane Season of 2005!

Lesson 2: The forecast track cone is often not big enough. The retiring director of NHC, May Mayfield, says that he wants the epitaph, "Don't look at the center track forecast line, look at the cone of possible tracks" engraved on his tombstone. Well, sometimes even the cone isn't big enough. The cone is based on the average track error in NHC forecasts over the past few years. Nearly half the time, the actual track of a storm will fall outside the cone. If you looked at those early forecasts of Ernesto going into the Gulf of Mexico, the cone did not quite extend all the way to the eventual landfall point at the extreme southern tip of Florida. Track forecasts are getting better--last year's 5-day forecasts were about as accurate as a 3-day track forecast 15 years ago--but there are many situations where the computer models and the human forecasters do poorly.

Next update
I'll have an update Monday morning.

Jeff Masters
Working Hard
Working Hard
My father and brother are working really hard, later it took me to work too..
Ernesto 9-1-06
Ernesto 9-1-06
Power poll down along 17 near the NC/SC border at junction of 9 and 17. This is the only real damage I saw from Ernesto other then some very minor limb damage.
This street it's a new arroyo now
This street it's a new arroyo now
As you can see this it's the water coming down the Mountains.(Yesterday)

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

morning everyone...ernesto was fun to drive around in...lol...its been a fun couple of days....no power for alot...flooded area...and now the james is rising today...lol...peak winds around richmond were sustained @ 42mph in a couple bands, with a few gust up to 58...all in all not too horribe, luckily my power was only out for a few hours...gotta love living near a hospital...lol...what are yalls thoughts on our next player out there??
welcome no2. This place is rather frustrating but also addicting. Have fun but watch out for the idiots.
I have to try to time my mite's discussions and forecast maps at a different time, it looks weird when I come out with a track forecast at the same time as the NHC. Link

I'll switch the timing. I will have another update on my site at 7PM that way we wont be on info track and discussion overload
2504. Ron5244
Seems like yours is just a little faster than the NHC's.

I hope its faster. I HATE watiting on slow ones.
hey york, how are you guys doing over there...my grandfather lives in glouchester...told me last night most of their power was still out...things getting better over there?
TY Jupiter...I will enjoy...What are some of the names I should trust? Anyone that I should ignore totally????
Hurricane79 thanks for the link. I remember your forcasts from last year. Always look forward to them.
if this storm was to come up through nc/va...you probly wont hear much out of most people from central/se va for at least a couple of days....when isabelle came through here...i was a lucky one and our power was still ut for 5 days....most had it out for 3-4 weeks...could be horrible for our area if it came through so soon after little e.
Guys here is the 12z Guidance... SORRY FOR THE LARGE IMAGE.



I don't want to start listing names but you will catch on real fast. Don't let anybody in here tell you what is going to happen. Listen to everyone and you will be able to figure it out. Most of all learn from the information that the NHC provides you with. They are not perfect but really good at what they do.
DEPRESSION ALMOST A TROPICAL STORM...

AT 1100 AM EDT...1500Z...THE CENTER OF TROPICAL DEPRESSION SIX WAS
RELOCATED NEAR LATITUDE 16.3 NORTH...LONGITUDE 42.7 WEST OR ABOUT
1235 MILES...1990 KM...EAST OF THE LESSER ANTILLES.

THE DEPRESSION IS MOVING TOWARD THE NORTHWEST NEAR 12 MPH AND THIS
GENERAL MOTION IS EXPECTED FOR THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. THE DEPRESSION COULD BECOME A TROPICAL STORM LATER TODAY OR
TONIGHT.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.

REPEATING THE 1100 AM EDT POSITION...16.3 N...42.7 W. MOVEMENT
TOWARD...NORTHWEST NEAR 12 MPH. MAXIMUM SUSTAINED WINDS...35 MPH.
MINIMUM CENTRAL PRESSURE...1005 MB.
2512. Ron5244
Now, I am an ammature when it comes to tracking the tropics. Only been doing it for 2 years. But I just find it puzzling that when it makes its bend to the west it is still moving slow. I find that odd because it will be under strong influence of the high by then.
I am starting to think that we will have TS Florence by 5
recon's plan of the day is out...no plans to fly yet.
yes think we will have a TS as well
too far out to say now but anyone feel this system (td 6) could affect florida??
The relocation of the center may have an affect on models later this afternoon.
2518. Ron5244
Posted By: stormhank at 3:00 PM GMT on September 04, 2006.
too far out to say now but anyone feel this system (td 6) could affect florida??


If it does affect FL (which is way to early to say)...this is what I think will happen.

It will affect us anytime next week, as a hurricane. Thats the only thing that can be said.
23, what affect do you think it will have?
The relocation of the center may have an affect on models later this afternoon.
Thanks Jupiter, Ill be back on the blog with an update closer to 7:30 or 8:00 tonite. I have to make a 5 hour drive now...


Have fun til then
TTYL


looks like the two circulatons are "merging" on td6..... i think this has been "one" of the inhibitors for further development..... but it appears that will soon be gone......


OT:RIP Crocadile Hunter!
2523. Ron5244
When are the next model runs?
2524. refill
I think that the track will shift more to the west because it is not clear the speed motion of TD6. I am not a meteoroligst but if they said that the ridge will build north of the TD I think that the motion will depend on how fast TD6 moves. Any opinions????
@ Skyepony

I didn't think they flew into anything east of 50W, but I don't really know these things. They'll probably fly in Wednesday afternoon or Thursday.
sorry guys i posted it twice.

Pipsneyy i think models may be shifted more to the south in reflect to the ridge forcast to build and center relocation.
Morning everyone, and Happy Labor Day!!!

Looks like td6 isn't really enjoying her labor day morning at all. LOL

It appears the trof and the shear it produced really did a number on td6 during the early am hours. I still think this TD will become TS Flo, but she definatly needs to do some reorganization today.



PS-GO NOLES!!!!
Anyone else interested in 99L??

From Dr. Ms Sunday update
Lesser Antilles tropical wave
A small tropical wave surrounded by a cloud of African dust is moving through the eastern Caribbean this morning. This wave, which NHC has designated "Invest 99L", is tracking west at 15 mph and has a small area of heavy thunderstorms associated with it. A large upper trough of low pressure over Cuba and Hispaniola that is creating about 10-20 knots of shear over 99L, preventing significant development. The trough is expected to weaken and move west over the next few days, potentially creating a low shear environment over most of the Caribbean. This could allow intensification of 99L into a tropical depression by Tuesday at the earliest. NHC has not run any preliminary models for this storm since yesterday.

I cant find any prediction data newer than 24-36 hours old can be seen on latest sat images
Anyone have anything on this one?
Im headed for Roatan in less than 2 weeks.
Look at this GFS:



Left to right: Florence, Gordon and Helene. Gordon is forecast to develop from the wave behind TD 6; Helene is still over Africa:

2530. Ron5244
Posted By: refill at 3:07 PM GMT on September 04, 2006.
I think that the track will shift more to the west because it is not clear the speed motion of TD6. I am not a meteoroligst but if they said that the ridge will build north of the TD I think that the motion will depend on how fast TD6 moves. Any opinions????


Well, its a large high so it will most likely affect TD 6 even if it does move slow. A big factor is how far north it is once under the influence of that high. Once it is, I say things will be under the gun and TD 6 or Florence will be moving more quickly and efficently. Just my opinion though..
Good morning, Labor Day bloggers! Sounds like we're going to get Flo and the 11 a.m. discussion is confounding compared to the models(know it's early); but, sure sounds like the NHC has this thing moving further west, south even. What's up with that and makes it still a WAG doesn't it?
2532. wxgssr
Skye...the yare saving their money for later on. Its out in the middle of the Atlantic, posing no immediate threat to anyone...its a LOOONNNGG flight just to get to the system for now...

They will rely on Sat interpretation for the time being...unless it starts to threaten the Antilles...they will just wait and watch. Once it gets N of the Lesser Antilles (IF it gets N of the Lesser Antilles), they will take greater interest in flying the storm.

Indicateing a more Westward motion in the extended forcast.The eastcoast has to be ready for the possibility that This system may miss the trof and continue west towards the coast.
2534. Ron5244
The GFS shows possible formation of Helene to turn out to see by Africa. So that one will be boring.
Being farther to the west that puts it closer to the trough thus being picked up by it a little more?
2536. Ron5244
sea*
23 Which one is the gfdl? Lets everyone keep their pants on. Look at 23s post the closest any of those models comes to Fl is about 800 miles. All we need is 50 or so miles. Our threat will most likely come from the south and southwest.
23, would that put florida in danger?
H23 just got back from the gym whats the latest and i just saw that image you posted where you find that
Is the high going to push TD6 towards the U.S?
2542. KG6ZLW
The computer models for John and the Atlantic this year seem to be consistently erroring on the western side. That is the storms track further east of the projected model. Is there some other force they are not calculating?
2543. Ron5244
Posted By: Pipsneyy at 3:15 PM GMT on September 04, 2006.
Is the high going to push TD6 towards the U.S?


Once it gets under the influence the high pushes it west. And that means it has no where else to go besides the US. (Assuming the high affects it while above 20 N) thats what is forecast.
Posted By: Ron5244 at 10:11 AM CDT on September 04, 2006.
The GFS shows possible formation of Helene to turn out to see by Africa. So that one will be boring


It threatens the Cape Verdes and possibly the Canaries...
Ron, so where would it push TD6?
I think it's funny how a lot of you who were here last night were saying it was going to be a fish storm, but now you're all changing your mind!
2547. Ron5244
Posted By: kylejourdan2006 at 3:19 PM GMT on September 04, 2006.
I think it's funny how a lot of you who were here last night were saying it was going to be a fish storm, but now you're all changing your mind!


I'm glad to say I'm not one of those people.
I wonder if the models will just keep constantly changing like they did with ernesto.
2549. wxgssr
1. Yes it could flatten out and affect the Antilles and Carribean.

2. Yes it could affect Florida

3. Yes it could cross Florida and affect the GOM

4. Yes it could affect the SE US

5. Yes it could afffect the Mid Atlantic

6. Yes it could affect New England

7. Yes it could recurve between NC and Bermuda and affect the Canadian maritimes and the N Atlantic.

8. Yes it could fail to develop and dissipate for now due to the trof but hang together as a wave and then do any of 1-7.

9. Yes it could be completely ripped apart by the trof and completely dissipate, never to be heard from again.

IMO, 4-7 are more probable.
Just an educated Wild Assed Guess.
2550. Ron5244
Posted By: Pipsneyy at 3:20 PM GMT on September 04, 2006.
Ron, so where would it push TD6?


That depends if the high allowed it to do some WNW motion rather than just due west, but it mostly depends on where it becomes uner full influence of the high.
Right now the storm looks rather sickly on infrared. I that shear is really taking it's toll. I imagine until the high sets up, the models will be all over the place as they usually are so early in the storm's genesis.
i wish the fish people were right!!
morning KYLE...
PipsneyyThis system could end up anywere but has to watched very closely because depending on how much the upper-level trough manages to pull the circulation north may be part of the key to an eventual track.The TROF is forcasted to lift out and be replaced by a strong ridge which will likely send this system on a WNW-W path in the coming days.The possibilty is their for it to miss the TROF and continue towards the eastcoast.Having said all that we have to see how things evolve in the coming days.
2555. Ron5244
Posted By: hurricane23 at 3:24 PM GMT on September 04, 2006.
PipsneyyThis system could end up anywere but has to watched very closely because depending on how much the upper-level trough manages to pull the circulation north may be part of the key to an eventual track.The TROF is forcasted to lift out and be replaced by a strong ridge which will likely send this system on a WNW-W path in the coming days.The possibilty is their for it to miss the TROF and continue towards the eastcoast.Having said all that we have to see how things evolve in the coming days.


So basically if it misses the TROF, the US is in for it?
I'd still be surprised if the storm didn't turn back like Floyd et al at the last second. There is so much troughiness over the South East and it doesn't seem to want to go away. Time will tell.
yes.
2558. VBgirl
I have a feeling about this one like I did Isabel..kinda feel like it has our name on it (VA/NC). Know it's WAY too early to tell anything though. Can't even count on the models yet.
new post by Dr. M you all.
Morning stormhank - Well I think anyone who said that this season was going to be a lull didn't see these next few weeks coming! LOL We may be talking three tropical cyclones within 3 weeks time (if the conditions hold together)! Also, GFDL is continuing to show a 966mb cyclone from TD6 in 5-days, so I'm not taking my eyes off this one!
What if it doesn't miss the trough?
Guys remember its all about timeing when a tropical system when it is approaching the U.S.I just everyone to understand that the possibilty is their for it to miss the TROF.Lets let things evolve and in the coming days were going to have a better on how the atmosphere is going to be shapeing up. Adrian
2563. Ron5244
Yeah, the only thing to do is wait and see.

ULL's form almost over night as one did with Ernesto before coming into South Florida, and Florida has been under a constant state of troughiness for at least 3 weeks separate from the trough out in the mid-Atlantic which is the one that is being talked about right now. Who knows what the atmosphere will bring in 5 days? We've been told by NHC of about high's building in scaring the crap out of everyone here in SOFLO only to have it fall apart or another early season front move faster than normal to catch the storm and shunt it away.
No offense to DocM; but his Labor Day must be busy. Didn't the NHC declare the 90L as TD06 last night? Not much meat in the Sunday forecast that I saw....that's okay, Doc, you're still the sage here, have a good LD.

He, apparently, thinkgs 99L still has a chance. Also, says, that 98L is being absorbed. Looks to me like these two, 98L and 90L, can't get together and may split with one going NW and the other west.

But, what do I know, NS, in comparison. Just seems like we've got several confusing things going on right now, and that surely tells me that just about anything is possible.
Monday forecast, rather. (must still have only one eye open...lol)
Dr. M's new update is out - been so for 45 mins
BRAND NEW ANIMATIONS from CycloneOz

Tropical Depression 6 - GOES Infrared Animation - Current to 9/4/2006 1245Z

and

Tropical Depression 6 - GOES Water Vapor Animation - Current to 9/4/2006 1345Z

The depression is still of to the east a bit of the GOES imagery...but you'll get to see the weather patterns that will influence this system in the coming days.