Tropical Storm Erika's future highly uncertain

By: Dr. Jeff Masters , 2:21 PM GMT on September 02, 2009

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The tropical wave we were calling Invest 94 finally decided to stop dawdling and become Tropical Storm Erika yesterday. However, Erika seems intent upon keeping us guessing about its intentions, as the storm's future track and intensity remain highly uncertain. After a modest burst of intensification to a 60 mph tropical storm last night, Erika has become quite disorganized this morning. The Hurricane Hunters found multiple swirling centers inside Erika early this morning, and the main center took a jump to the southwest to relocate itself under a batch of intense thunderstorms. The exact location and path of Erika remain uncertain at this point, and it is possible the storm will have another center relocation later today. Wind shear analyses from the University of Wisconsin diagnose a moderate 10 - 15 knots of shear over Erika, a decrease from yesterday. SSTs are warm, 29°C. Why, then, is Erika so disorganized? The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone. Upper air data from Guadeloupe and Saint Martin from last night show a complicated shear pattern in Erika's region, with 30 knot winds out of the south to southwest at 200 mb height, nearly calm winds between 300 - 500 mb, and northeasterly winds of 10 - 20 knots from the surface to 500 mb. Some extremely dry air with humidities near 10% was present in a thin layer near 600 mb on the Guadeloupe sounding, so dry air from the Saharan Air Layer is probably being injected by a northeasterly jet of wind into the core of Erika. The shear of 30 knots at the top of the storm is ripping away the heat and moisture Erika's thunderstorms are lifting there, and the result of the shear and dry air is a very disorganized tropical storm.

Erika is embedded in a weak steering current pattern, and the future track of the storm will depend greatly upon how strong the storm gets over the next few days. A stronger Erika will extend higher into the atmosphere and be steered more to the northwest by upper-level winds. A weaker Erika will be steered more by the low-level winds, which will keep the storm on a more westerly track. Given the complicated nature of the wind shear pattern in the region, it is difficult to forecast how strong Erika will get. Virtually anything can happen over the next five days, from dissipation (as forecast by the ECMWF model) to intensification to a Category 3 hurricane (as forecast by the HWRF model). Large-scale wind shear is expected to increase to 20 - 25 knots between 3 - 4 days from now, so Erika will have to deal with an increasing amount of adversity. The storm is a long-term threat to the Bahamas and U.S. East Coast, particularly if the storm stays weak over the next three days. Potential landfall solutions from the models range from Florida on Tuesday (GFS model) to North Carolina on Wednesday (Canadian model).


Figure 1. Morning image of Tropical Storm Erika, showing a false center over Guadaloupe--one of several surface swirls the Hurricane Hunters found in the storm.

Elsewhere in the tropics
The tropical wave off the coast of Africa we were watching on NHC's Tropical Weather Outlook as having a low chance of developing into a tropical depression has been done in by the dry air of the Sahara, and is no longer a threat to develop. A large and well-organized tropical wave will emerge from the coast of Africa on Thursday, and several of the models develop this low into a tropical depression by early next week. The remains of an old cold front off the coast of North Carolina could serve as a breeding ground for some tropical development Friday or Saturday, but anything that forms in this region would get swept quickly northeastward into New England by Sunday without enough time to become a tropical depression.

Hurricane Jimena nears Baja
Hurricane Jimena has steadily weakened over the past day, and is now down to a Category 2 hurricane with 105 mph winds. The storm should continue to steadily weaken over the next 24 hours as the waters under the hurricane cool from 28°C to 27°C. Jimena is battering a relatively unpopulated stretch of coast, and largely spared the tourist mecca on the southern tip of Baja. It now appears unlikely that moisture from Jimena will reach the Southwestern U.S., and the hurricane appears poised to stall out over Baja and die five days from now.


Figure 2. Hurricane Jimena on Tuesday, Sep. 1, 2009, as seen by NASA's MODIS instrument. Image credit: NASA Earth Observatory.

Baja's hurricane history
The most powerful hurricane on record to hit the west coast of Baja occurred last year, when Hurricane Norbert made landfall on the central Baja coast with sustained winds of 105 mph (Category 2) . Norbert's central pressure of 956 mb at landfall made it the 3rd strongest hurricane to hit the Pacific coast of Mexico since record keeping began in 1949. Norbert killed eight, knocked out power to 20,000 homes, and damaged or destroyed 40% of the homes on the islands of Margarita and Magdalena. Norbert crossed the Baja Peninsula and made landfall on Mainland Mexico as a Category 1 hurricane with 85 mph winds.

Only two major hurricanes have made landfall on Baja since record keeping began in 1949. Both hurricanes hit the east (Gulf of California) side of Baja. The first was Hurricane Olivia of 1967. Olivia made landfall on October 13, 1967 as a Category 3 hurricane with 125 mph winds. Due to its small size and the unpopulated region of coast it hit, damage was minimal. The second major hurricane was Hurricane Kiko, which made landfall on August 27, 1989, as a Category 3 hurricane with winds of 115 mph (minimal Category 3). Kiko was a small hurricane and hit a relatively unpopulated area, resulting in no loss of life and only scattered reports of damage.


Figure 3. A plot of all the major hurricanes to pass within 200 miles of Mexico's Baja Peninsula since 1949. Image credit: NOAA Coastal Services Center.

California fire webcams
As I discussed in yesterday morning's post, you can use our wundermap for Los Angeles with the fire layer turned on to see where the fire and smoke are located, and track the temperatures and winds during today's air pollution event. We also have two webcams with views of the fire: Altadena and Tujunga.

I'll have an update by 4pm this afternoon, when the data from the next hurricane hunter flight into Erika will be available.

Jeff Masters

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Quoting apocalyps2:
If Erika should cross France it could mean trouble for the entire coest of england.
Especially now that erika has so much convention.


Ok funny at first. Now it is getting old.... Please stop. Some of us on here really want to know, and learn about what is going on.
Quoting connie1976:
I don't mean to be repeating myself....but I'm paranoid....

can someone tell me how to tell if I picked up that virus someone said was here...I just ran my trend micro antivirus plus antispyware....but all that came up were cookies...


Yes you have a virus.
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1258. JLPR
Does this mean it will down graded @ 5

im thinking we might have a depression but it could make a comeback tomorrow
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1257. Brillig
Quoting Patrap:


Looks like Texas is saying, "Speak to the hand." (re post: 1194)
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Can't question the hurricane hunters.....they are in the storm....satellites and us are not.
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I hate viruses. Every time one pops up on here it shuts down IE and I can't use it on this site until the virus is removed from here. IE works on everything else. I just use Firefox for here.
Don't know if its some security thing built in to IE or my computer but apparently it won't let me get it...So far.
Member Since: August 15, 2008 Posts: 10 Comments: 3665
1253. Ossqss
BTW, I would add on the virus item. I handed my laptop off to my helpdesk to ensure it was cleaned up properly, and they ran the malwarebytes program and blew it up. The heuristics and additional scan pulled up 6 files in security center and they proceeded, without paying attention to what they were doing, with removing them. Be careful. Thankfully, I ghost my drive regularly. Even the pros make mistakes. I hope he finds another job :)
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Quoting antonio28:


Fred?? OMG this is gone to be a CV season.


What is CV?
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Quoting Floodman:


Odd...well, I suggest using a secondary program like Malwarebytes to double check the primary VS software...it catches registry errors as well

You;d be surprised how many IT folks are in here...glad to meetcha, by the way!
Hearing about all these security related Windows OS workaround hoops you all have to jump through to have a secure machine makes me love my Linux OS all the more. There are ZERO linux viruses in the wild and the permissions structure stops malware cold while still on the doorstep.
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Can anyone please tell me what do they think will happen to us here in Puerto Rico with Erika? TIA
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Quoting connie1976:
can someone tell me how to tell if I picked up that virus someone said was here...I just ran my trend micro antivirus plus antispyware....but all that came up were cookies...


You getting a popup that says "Antivirus Pro has detected viruses on this computer, click here to remove them"?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
I don't mean to be repeating myself....but I'm paranoid....

can someone tell me how to tell if I picked up that virus someone said was here...I just ran my trend micro antivirus plus antispyware....but all that came up were cookies...
Member Since: Posts: Comments:
Quoting apocalyps2:
If Erika should cross France it could mean trouble for the entire coest of england.
Especially now that erika has so much convention.
dude get a life!!!
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Quoting jasoniscoolman10:


Fred?? OMG this is gone to be a CV season.
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Quoting OSUWXGUY:


Ok I can accept that. Not a true CoC reading then...


Does this mean it will down graded @ 5
Erika attempting a strong comeback this evening.Not as sheared from the SW to NE as earlier.
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1242. IKE
Quoting kmanhurricaneman:
you know the more i look at the RGBloop iam more convinced that the coc is now located to the sw of guadeloupe.


That's what I see too. I see no other spin.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting TheCaneWhisperer:


FROM THE NHC

THERE ARE
MULTIPLE SWIRLS APPARENT ON THE SATELLITE IMAGERY ROTATING IN THE
LARGER CIRCULATION ENVELOPE WITH A MEAN CENTER TO THE WEST OF THE
DEEP CONVECTION.


Ok I can accept that. Not a true CoC reading then...
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1240. Brillig
In the last 24 hours Erika seems to have gone almost due west, with quite a bit of confusion in the interim. I put the confusing part in a wide, transparent path, and the relatively obvious part in a thin, opaque path.
16°35'59.21
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18Z surface missed as well, no peekie.

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Quoting RayRayfromLa:
I hope the 2:00pm GFS model run is wrong! They have it shooting the gap and into the GOM.


That my dear, could be bad
1237. Seastep
1200. Relix 2:58 PM EDT on September 02, 2009 Hide this comment.
For those getting viruses...

Firefox + AdBlockPlus works perfect. No warning here at all.

--- end quote ---

Using that setup also.

1. Paid member
2. Not clicking on anything
3. FF + Adblock plus

Still detected. Didn't get through, but detected in the browser cache and deleted.
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you know the more i look at the RGBloop iam more convinced that the coc is now located to the sw of guadeloupe.
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I hope the 2:00pm GFS model run is wrong! They have it shooting the gap and into the GOM.
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Quoting Orcasystems:


I have to admit..after watching hundreds of Vortex runs on Google earth.. this one was just not right... I don't think they actually hit it right on. They never even got down to a low wind.. or multiple directional airs.



They ought to do at least one more center pass before leaving the storm. See what they post then. They're still finding strong southerly winds 30-40 knots at flight level east of the circulation.

Still a fairly interesting circulation on the TPW product as well. Seems like a due west motion should commence soon.

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1233. usa777
Take a look at this link. Tell me if you think Erika is dying.

http://www.star.nesdis.noaa.gov/smcd/opdb/aviation/loops/realtime/atlir_loope.html
Slow down the loop and look at the last frame.
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1232. Seastep
Floodman - nice to meet you to.

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can someone tell me how to tell if I picked up that virus someone said was here...I just ran my trend micro antivirus plus antispyware....but all that came up were cookies...
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Quoting Orcasystems:


Not what you see on a normal Vortex Run... no white markers at all.


Please explain to me what that means, sorry about all the questions I am attempting to gain all the knowledge I can
1227. IKE
12Z ECMWF dropped Erika....
Member Since: June 9, 2005 Posts: 23 Comments: 37858
With the current motion of Erika the latest GFDL seems the most realistic model at this point.
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1225. Ossqss
I stopped a Trojan loader a few weeks back via windows defender. McAfee (enterprise) did not pick it up or the PWS:Win32/Daurso.A trojan, which has many names.
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It appears the naked swirl (appearing to NOT the center) is over Guadeloupe, thus the light winds, correct?
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1223. centex
I'm a paid member. Maybe some not getting it "message about it on access to any WU page" because there virsus software not detecting it.
Member Since: August 10, 2007 Posts: 0 Comments: 3235
Quoting apocalyps2:


Go into the carribbean,and explode on sunday.
My mean concern is to keep the egyptian pyramides safe.




Yeah..... well...I have a company that makes hurricane shutters just for the pyramides. But I require a 75% deposit up front.


Not what you see on a normal Vortex Run... no white markers at all.
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Quoting IKE:


True. I've had multiple handles of his on ignore. I'll add the new one.


Wearing out my button, man!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting Patrap:


The Bug is Embedded in a Google Ad Banner..

Seems the WU IT folks cant review and scan the Ads,they just cash the checks and Load um u.


yup pretty sad that this site could care less about its members
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1218. JLPR
I see
The virus seems to save itself in the cache
so if you got a warning clear out your cache and do a scan =]
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1217. Patrap
Quoting JLPR:
yep loks liek WU has a bug
my antivirus just blocked a trojan

and I only entered the blogs page


The Bug is Embedded in a Google Ad Banner..

Seems the WU IT folks cant review and scan the Ads,they just cash the checks and Load um up.
Member Since: July 3, 2005 Posts: 424 Comments: 128344
Quoting cybergrump:

114-117 Knots right when it reaches the bahamas



Hey you never know. I can't think of one time she has done anything expected of her.
Erica needs to **@!! or get off the pot!!!
she is pissing everyone off including the NHC. No one has a clue what is going to happen to this system. Im tired of looking at her doing nothing for the last few days. I starting to think that she may just POOF go away.
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1213. JLPR
5.4 mph / 8.7 km/h / 2.4 m/s from the SSE

not that much wind from Guadeloupe =P
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1212. RJT185
yeah, uncertain, i'd say. very crazy system.
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Quoting JLPR:
nope im not a paid member

but I got all the ads blocked with AdBlock
so I dont know what happened


Adblock isn't 100% effective, especially if the script in question was written to exploit a security weakness...
Member Since: August 2, 2006 Posts: 10 Comments: 9922

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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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