Tropical Storm Helene arrives; 94L a potential threat to the Lesser Antilles

By: Dr. Jeff Masters , 10:41 PM GMT on August 17, 2012

After a long path across the Atlantic that mirrored the track of Hurricane Ernesto, Tropical Depression Seven finally got its act together enough over the Bay of Campeche tropical storm breeding grounds to earn the name Helene. Helene's formation on August 17 ties 2012 with 1933 for the 2nd earliest appearance of the Atlantic's eighth tropical storm. Only 2005 had an earlier formation date of the season's eighth storm. Most of this year's storms have been weak, though, so the total Accumulated Cyclone Energy (ACE) of 21 is not that much higher than the normal year-to-date ACE of 15, based on a 1981 - 2010 ACE climatology. The normal yearly ACE for the Atlantic is 104. Helene doesn't have much room to work with before landfall, but has the potential to be a prodigious rainmaker for Mexico, with NHC predicting 5 - 10 inches for portions of Northeast Mexico. This part of the coast is not in drought, so will be prone to heavy flooding. Fortunately, Ernesto's main rains fell to the south of where Helene's rains are falling. Helene's rains should remain south of Texas, though we can't rule out a few thunderstorms bringing 1 - 2 inches of rain to extreme South Texas on Saturday and Sunday.


Figure 1. Afternoon satellite image of Helene.

94L a potential threat to the Lesser Antilles
A large tropical wave emerged from the coast of Africa Thursday night, and was designated Invest 94L by NHC this Friday morning. The models have been impressed this system, and develop it into a tropical storm by the middle of next week. The latest set of 12Z (8 am EDT) model runs are divided on how far west 94L will make it before curving more to the northwest. The ECMWF model keeps 94L weak for the next 5 - 6 days, and has progressively been bringing the storm closer to the Lesser Antilles Islands with each successive run. The ECMWF predicts 94L will pass very close to the northern Lesser Antilles August 24 - 25 as a weak tropical storm. The 12Z GFS model predicted recurvature of 94L well to the east of the Lesser Antilles and Bermuda, but the latest 18Z run has the storm plowing through the Lesser Antilles on Thursday, August 23, as a strong tropical storm, then becoming a hurricane in the Eastern Caribbean. Given that our two top models for forecasting hurricane tracks are increasingly showing a threat to the Lesser Antilles, residents of the islands should pay close attention to the progress of 94L. The eventual track of 94L will depend on the strength of the storm over the next seven days, which is difficult to forecast, since 94L will have the usual trouble with dry air to the north from the Saharan Air Layer (SAL.) With the models changing their tune drastically from run to run, its tough to say what land areas might be most at risk from the storm in the long term. In their 2 pm EDT Tropical Weather Outlook, NHC gave 94L a 10% chance of developing into a tropical depression by Sunday afternoon.


Figure 2. MODIS satellite image of Invest 94L taken at 8 am EDT August 17, 2012, off the coast of Africa. Image credit: NASA.

Jeff Masters


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

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 676 - 626

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36Blog Index

2012..year of the multiple centers.
Member Since: Posts: Comments:
Besides the MLC diving into mexico, I don't see any rotation here.
Member Since: Posts: Comments:
WOW big hurricane
Quoting sunlinepr:


You said that and the NHC heard it.... and updated it...

Member Since: Posts: Comments:
Quoting TWX13

NHC has to merge the two systems before any more initializations can take place. I think they've had it with wildly divergent models as much as we have due to multiple centers.
Member Since: Posts: Comments:
Quoting sunlinepr:


You said that and the NHC heard it.... and updated it...

Crappty crap crap!!
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:
Call me dumb, but I had no idea 94L was so massive.



You said that and the NHC heard it.... and updated it...

If it keeps expanding that will be a Gilbert....

Member Since: December 31, 1969 Posts: Comments:
Sorry about double post.
Member Since: Posts: Comments:
Quoting sunlinepr:


Well, there are many studies that are on the way that will eventually be available... though they have to fight big interests that are blocking them....


But here is one of the latest news....


Title: Japanese beef exports to US postponed
Source: NHK WORLD English
Date: Aug. 17, 2012

Japan has been forced to put off resuming beef exports to the United States at the last minute, due to US concerns about effects of last year%u2019s nuclear accident.

Shipments were due to resume on Saturday starting with cattle processed that day.

Japanese beef exports to the United States had been suspended for over two years after an outbreak of foot-and-mouth disease in the southwestern prefecture of Miyazaki.

But Japanese officials say the US side requested a halt on Thursday, saying it wanted to check how Japan is inspecting beef and managing feed to prevent radioactive contamination.


Link
The most amazing part of this story is that AMERICA is importing JAPANESE beef... doesn't quite fit my image...
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:

Appears that 94L is absorbing the feature to the west.


Low in front of 94L dissipates according to the 00z TAFB analysis.

Member Since: Posts: Comments:
Quoting scott39:
Tropical Atlantic has Helene moving NNW at 7mph on the 00Z on 8/18/2012. Also note that thier coordinates are 20.8N 96.1 W Looks like Helene may be starting the swing towards the E a little. Im not saying that its not going into Mexico....but still interesting. The latest TVCN model that the NHC likes, is turning it more N and E too.
Member Since: Posts: Comments:
Quoting Levi32:


Well the topography of the bay is exactly what makes the southern side (westerly winds) stronger than the northern side in most BOC systems. That part wasn't unusual at all.


Unusual for a TS, not for the BOC. This one is a farce
Member Since: Posts: Comments:
Quoting kmanislander:


There are two separate featurs in that WV image. 94L is near 25 W. There is another wave further West.

Both had distinctive surface lows based upon earlier Ascat and Osacat passes.


Those two lows fighting could keep this in check for a few days and keep it further south

possibly why the models stayed further south, once the two lows end their fight, the system intensifies into a strong system
Member Since: Posts: Comments:
Quoting bappit:

BULLETIN
TROPICAL STORM HELENE ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072012
1000 PM CDT FRI AUG 17 2012

...HELENE BARELY A TROPICAL STORM BUT COULD REGAIN SOME STRENGTH ON SATURDAY...


SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.0N 96.4W
ABOUT 65 MI...105 KM E OF TUXPAN MEXICO
ABOUT 125 MI...205 KM SE OF TAMPICO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES



Oh! there is. thank you
Member Since: Posts: Comments:
Quoting RTSplayer:
Either the storm is inland, or this web site is bugged.

Take your pick.

Link

and



The damn thing would have to be off by nearly a full degree in each direction in order for the center to NOT be over land...
Your eyes can deceive you.
Member Since: Posts: Comments:
Quoting kmanislander:


There are two separate featurs in that WV image. 94L is near 25 W. There is another wave further West.

Both had distinctive surface lows based upon earlier Ascat and Osacat passes.

Appears that 94L is absorbing the feature to the west.
Member Since: Posts: Comments:
Quoting BahaHurican:
They certainly haven't been pretending it going to last very long....

Personally I think they named it so DC115 can get her wish about Isaac... lol... [Keep telling u guys they read the blog... lol]


LOL
Member Since: Posts: Comments:
Quoting kmanislander:


Not chastising but the fact that the strongest winds were in the SW quad, which is most unusual, was a clear sign that this was not a sustainable system. the first discussion even went so far as to suggest that the winds may have been on the generous side due to the topography of the Bay, something I posted about before the discussion came out. Waiting a little may have resulted in a somewhat more objective determination but with the 5 pm timeline pressing who knows.


Well the topography of the bay is exactly what makes the southern side (westerly winds) stronger than the northern side in most BOC systems. That part wasn't unusual at all.
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:
Call me dumb, but I had no idea 94L was so massive.



There are two separate featurs in that WV image. 94L is near 25 W. There is another wave further West.

Both had distinctive surface lows based upon earlier Ascat and Osacat passes.
Member Since: Posts: Comments:
Tropical Atlantic has Helene moving NNW at 7mph on the 00Z on 8/18/2012. Also note that thier coordinates are 20.8N 96.1 W Looks like Helene may be starting the swing towards the E a little. Im not saying that its not going into Mexico....but still interesting. The latest TVCN model that the NHC like is turning it more N and E too.
Member Since: Posts: Comments:
Quoting BahaHurican:
New one already???

im looking but cant find it. I read a very interesting article on how dangerous a strong typhoon would be if it directly hit the fukashima plant, cant seem to find it.
Member Since: Posts: Comments:
Quoting kmanislander:


Those winds were produced in large part by proximity to the SW terrain of the Bay. Still, they named it but no surprise the shelf life is less than a mayonnaise sandwich.
They certainly haven't been pretending it's going to last very long....

Personally I think they named it so DC115 can get her wish about Isaac... lol... [Keep telling u guys they read the blog... lol]
Member Since: Posts: Comments:
I think the NHC is doing what they were doing with Ernesto.At one point Ernesto was a open wave but they decided not to drop it because it would cause problems down the road.Helene may be the same.some models show it as a intensifying storm headed for northern TX or Louisiana.
Member Since: Posts: Comments:
Quoting mitthbevnuruodo:


And what a tight freaking eye before it hit FL...


Oh yeah!
Member Since: Posts: Comments:
Call me dumb, but I had no idea 94L was so massive.

Member Since: Posts: Comments:
No 8PM Computer Model for 94L why??
Member Since: Posts: Comments:
Either the storm is inland, or this web site is bugged.

Take your pick.

Link

and



The damn thing would have to be off by nearly a full degree in each direction in order for the center to NOT be over land...
Member Since: Posts: Comments:
649. JLPR2
Quoting TropicalAnalystwx13:
The 00Z update for Invest 94L did not come out for some reason.


Ah, yes! Been looking around and nothing, everything is at 18z still. :\
Member Since: December 31, 1969 Posts: Comments:
Quoting WeatherfanPR:
Where is Helene ? That's the question!

BULLETIN
TROPICAL STORM HELENE ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072012
1000 PM CDT FRI AUG 17 2012

...HELENE BARELY A TROPICAL STORM BUT COULD REGAIN SOME STRENGTH ON SATURDAY...


SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.0N 96.4W
ABOUT 65 MI...105 KM E OF TUXPAN MEXICO
ABOUT 125 MI...205 KM SE OF TAMPICO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES
Member Since: Posts: Comments:
647. JLPR2
Quoting VAbeachhurricanes:


HEY! no negative thinking!!!


XD
Relax, it's not the fact that you disagree with the NHC, it's they way you said it that have people here going against what you said.

I wouldn't have named it either, I probably would have left it at TD strength.
Member Since: December 31, 1969 Posts: Comments:
The 00Z update for Invest 94L did not come out for some reason.
Member Since: Posts: Comments:
Quoting SFLWeatherman:
‎20 years ago today on 8/17/92, a tropical storm formed in the central Atlantic and was given the name Andrew.


And what a tight freaking eye before it hit FL...
Member Since: Posts: Comments:
Quoting wxmobilejim:

What time would that be in Central time?
One hour earlier, at about 11 p.m. They come out at Midnight English time, but are not available for about 4 hours...
Member Since: Posts: Comments:
Nice vort with 94L.I think that's where the most dominant center is.

Post 638 you can delete that...
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting JLPR2:
Even though I know the NHC knows what they are doing, I have never seen a tropical storm with such a weak reflection at the 850mb level. You have 94L and Gordon for comparison.



HEY! no negative thinking!!!
Member Since: Posts: Comments:
Where is Helene ? That's the question!
Member Since: Posts: Comments:
cant bash the nhc they had hh measured winds. if they hadnt called it i think more complaints.
Member Since: Posts: Comments:
Quoting washingtonian115:
Helene was named okay?.Deal with it dammit!.DEEEEAL with it.


No need to go over the top :-)
Member Since: Posts: Comments:
637. JLPR2
Even though I know the NHC knows what they are doing, I have never seen a tropical storm with such a weak reflection at the 850mb level. You have 94L and Gordon for comparison.

Member Since: December 31, 1969 Posts: Comments:
Quoting Hurricanes101:
Dmin can do some pretty shocking things to systems, we could just say wait and out and see what happens before we chastise the NHC

but whatever


Not chastising but the fact that the strongest winds were in the SW quad, which is most unusual, was a clear sign that this was not a sustainable system. the first discussion even went so far as to suggest that the winds may have been on the generous side due to the topography of the Bay, something I posted about before the discussion came out. Waiting a little may have resulted in a somewhat more objective determination but with the 5 pm timeline pressing who knows.
Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
Quoting HadesGodWyvern:
Japan Meteorological Agency
Tropical Cyclone Advisory #1
TROPICAL DEPRESSION 16
9:00 AM JST August 18 2012
====================================

SUBJECT: Tropical Depression In Sea East Of The Philippines

At 0:00 AM UTC, Tropical Depression (1008 hPa) located at 19.0N 126.0E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving south at 6 knots.

Dvorak Intensity: T2.0

Forecast and Intensity
========================

24 HRS: 18.5N 124.5E - 35 knots (CAT 1/Tropical Storm)
New one already???

Member Since: Posts: Comments:
Quoting floridaT:
very good post. long range effects. wonder when the studies will come out about japan radio activity effecting the west coast of the US


Well, there are many studies that are on the way that will eventually be available... though they have to fight big interests that are blocking them....


But here is one of the latest news....


Title: Japanese beef exports to US postponed
Source: NHK WORLD English
Date: Aug. 17, 2012

Japan has been forced to put off resuming beef exports to the United States at the last minute, due to US concerns about effects of last years nuclear accident.

Shipments were due to resume on Saturday starting with cattle processed that day.

Japanese beef exports to the United States had been suspended for over two years after an outbreak of foot-and-mouth disease in the southwestern prefecture of Miyazaki.

But Japanese officials say the US side requested a halt on Thursday, saying it wanted to check how Japan is inspecting beef and managing feed to prevent radioactive contamination.


Link
Member Since: December 31, 1969 Posts: Comments:
18z GFS ENSEMBLE MEMBERS coming out now it go up to 96HR now
Member Since: Posts: Comments:
Quoting washingtonian115:
Agree why so much bashing?.This does deserve to be a T.C to say the least.The NHC know what they are doing.Now I don't agree with everything they do but I think they made a good call.


Pretty sure its just me Wash ;)
Member Since: Posts: Comments:
Quoting RTSplayer:


I've seen them be off by 50 or even 100 miles before, and a few hours later issue a re-position, even though the official direction of movement was quite the different direction.

It has happened before a few times.

I guess we'll just see in the morning. If Helene is inland, as you insist, we shall still see DMAX footprint go up. If it's offshore, like all the conspiracy theorists contend, we'll ALSO see DMAX growth. The growth will either be over land or over water.
Member Since: Posts: Comments:
Quoting Hurricanes101:
Dmin can do some pretty shocking things to systems, we could just say wait and out and see what happens before we chastise the NHC

but whatever
Agree why so much bashing?.This does deserve to be a T.C to say the least.The NHC know what they are doing.Now I don't agree with everything they do but I think they made a good call.
Member Since: Posts: Comments:
Quoting kmanislander:


Saw that. First impressions !


You decide in 3 seconds whether or not you'll like someone. Or in this case name a TS lol
Member Since: Posts: Comments:
we will see helene may have outdone jose
Member Since: Posts: Comments:
He needs to have a chill pill lol.Relax!!
Member Since: Posts: Comments:

Viewing: 676 - 626

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36Blog Index

Top of Page

Category 6™

About

Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather