Tropical Storm Erika's future highly uncertain

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

Share this Blog
2
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

Sign In or Register Sign In or Register

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

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

Viewing: 61 - 11

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 | 28Blog Index

Quoting DestinJeff:


nothing to do with track, etc... just how frustrating it was when it lingered so long in the same general area without ramping up or down ... just hung out and caused Blog-fatigue

OK,dats cool.
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Quoting DestinJeff:
Nice convective increase

Um. I see a decrease in convection or are my eyes telling me porky pies.

BTW Good Evening/Morning all
Member Since: Posts: Comments:
Erika still has quite a long way to go structurally.

Member Since: Posts: Comments:
"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."

Glad Dr M made this point, as it is clearly not understood a lot of posters during the last few days.

Sometimes you just have to use your eyes and look at sattelite images to see the shear.
Member Since: Posts: Comments:



Quoting caneswatch:
Does anybody have the latest model runs?



Hey Breald, how are ya? It appears this one is anybodys guess.
Member Since: Posts: Comments:
Thx Doc...
Member Since: Posts: Comments:
12 Z Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




12 Z Dynamic Models (More sophisticated models)



Member Since: July 3, 2005 Posts: 430 Comments: 131147
Quoting rwdobson:


It's a little more than that. The "main" computer model runs are the very best estimate. They have the best estimates of input data and are run at the highest resolution.

The ensemble models are run at a lower resolution, with input data changed to reflect possible errors within the original input data. This is done to give a "what if" idea of the range of possibilities. They do not show the best estimate, however.



I was trying to "keep it simple", but yes your explanation is much better.
Member Since: March 10, 2006 Posts: 0 Comments: 11271
Off to work... you guys have fun and play nice...

Blog Update
Reflector site for those at work, includes Dr. Masters & Weather456, daily update.


AOI

AOI

AOI

AOI
Member Since: Posts: Comments:
dakster -
Agree - All hinges on that trough! LOL
Member Since: Posts: Comments:
Quoting Dakster:


Ensemble models are computer models. The difference is that with ensemble models subtle changes are made to atmospheric (and other) conditions.


It's a little more than that. The "main" computer model runs are the very best estimate. They have the best estimates of input data and are run at the highest resolution.

The ensemble models are run at a lower resolution, with input data changed to reflect possible errors within the original input data. This is done to give a "what if" idea of the range of possibilities. They do not show the best estimate, however.

Member Since: Posts: Comments:
The 12z NAM loses Erika by 8pm tonight.

Here's the 60hour frame:
Member Since: Posts: Comments:
Quoting DestinJeff:
i ususally mock the "this storm reminds me of" posts ... but Chris '06.

I usually don't comment on them either but, what is the point? I just don't get what that has to do with anything. Different time, conditions, place, circumstances. Is it going to do exactly what Chris did? Betcha it won't. So what is the point?
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Quoting Patrap:


Yup..that alone should be good for lets say,..about 3000 Post.


Bawhahaha! I'm thinking there's going to be a need for those white jackets w/the funny sleeves.....

LOL -- I could just see people desperately typing w/theirs nose or toes

Off to work
Member Since: Posts: Comments:
HA! All you people that said WeatherStudent was banned for life can eat crow...

-----------

NoNamePub - Yeah. It could and hopefully wouldn't have enough time to do so. At this point a CONUS landfall between Brownsville, TX and Bangor, Maine seems plausible.
Member Since: March 10, 2006 Posts: 0 Comments: 11271
Does anybody have the latest model runs?
Member Since: Posts: Comments:
Quoting TheCaneWhisperer:
Atmoaggie.

Waters north of the islands are cool yes but, the area around the NW Bahamas & SE FL Coast & GOMEX are much warmer.

Someone had asked earlier why some of the models blew up Ericka when it got around FL. That would be one of the reasons.

Yep. Missed the question.
That is about where the OHC becomes very conducive to a heady system.
Member Since: Posts: Comments:
Quoting Dakster:
Uhh ohh. Dr. M used the "F" word in his blog... (Florida)


Atleast he didn,t drop the "G Bomb"!
Member Since: Posts: Comments:
Finally,..one Year ago Today..


2 Sept 2008



Member Since: July 3, 2005 Posts: 430 Comments: 131147
Erika has multiple personalities. she has put everybody in the trick bag!! She is not behaving at all.
Member Since: Posts: Comments:
Dak, I think the Doc meant that if it stays weak it will make it to the Bahamas. From there it's game on. Personally, I'm hoping it just dissipates through disorganization and shear.
Member Since: Posts: Comments:
Quoting Seflhurricane:
he also mentioned the NC Word North Carolina get you helmets on and prepare to be bombarded by stupid and ridiculous comments



A lot can happen in 6 to 7 days. Still may go out to sea. Current wave is westward ho.
34. LBAR
Quoting IKE:
System just has too much going against it to be a major threat, wind wise. Biggest threat is heavy rains.

Just my unprofessional opinion.

Thanks Doc. Have a nice Wednesday!


Heavy rain in central South Carolina and that other Carolina would be a good thing. It's been dry, dry, dry.
Member Since: Posts: Comments:
Dakster - No quite -
If it stays weak until its gets into the warm Gulfstream - it could intensify -
Not-likley but possible -

I think with all that is against it...it will still Slowly get its act together and slowly curve north.....I don't know - Maybe Jacksonville on Weds night?

THOUGHTS?
Member Since: Posts: Comments:
3762. Bubu77

Je commence à craindre les inondations chez moi en Martinique parce qu'il y a une énorme convection sous ce systeme !!!

Veri Bad

Je craint un remake de Klaus ou 7 personne avaient été tué en Martinique


Bubu77,
quelle est la date du Klaus? et la categorie?
Avec Erika, il faux faire attention aux declarations officielles de NHC:

http://www.nhc.noaa.gov/

Stay safe!
Member Since: Posts: Comments:
Quoting IKE:


Amen Bro!

To all Florida wishcasters...Don't Call Us...We'll Call U.


Well, if Erika does threaten Florida, here is one person you will see much less of on here. Too much work to do at that point! UGH!!
Member Since: Posts: Comments:
he also mentioned the NC Word North Carolina get you helmets on and prepare to be bombarded by stupid and ridiculous comments
Member Since: Posts: Comments:
next SEASON please. el niño is here, get just to it.
Member Since: Posts: Comments:
Great Update Doc. Thanks for sorta clearing up the false center debate. It will be interesting to watch if she really gets her act together and forms a new more stable center.

It seems like this is the year of exposed/reforming centers. Ana, Claudette (sort of), Danny and now Erika.
Member Since: Posts: Comments:
25. IKE
Quoting Patrap:


Yup..that alone should be good for lets say,..about 3000 Post.


Amen Bro!

To all Florida wishcasters...Don't Call Us...We'll Call U.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Atmoaggie.

Waters north of the islands are cool yes but, the area around the NW Bahamas & SE FL Coast & GOMEX are much warmer.

Someone had asked earlier why some of the models blew up Ericka when it got around FL. That would be one of the reasons.
Quoting Dakster:


Ensemble models are computer models. The difference is that with ensemble models subtle changes are made to atmospheric (and other) conditions.


Thank you
Member Since: Posts: Comments:
Quoting Patrap:


Yup..that alone should be good for lets say,..about 3000 Post.


Really? Only 3,000 for the hour... That seems kind of low.

Good news for Florida is that if the storm inteisifes, it will miss Florida. If the storm stays weak it would hit Florida as a TS... Unless I am missing something in Dr. M's blog post.
Member Since: March 10, 2006 Posts: 0 Comments: 11271
Quoting Dakster:
Uhh ohh. Dr. M used the "F" word in his blog... (Florida)


Yup..that alone should be good for lets say,..about 3000 Post.
Member Since: July 3, 2005 Posts: 430 Comments: 131147
Quoting nolesjeff:
Thanks for update Doc, this should be a very interesting week.


Hey Noles, it seems like NC will have to keep an eye on this one.
Member Since: Posts: Comments:
8: As childish as most of the worst antics that go on in here. Maybe you should have stayed at Evangel another year. Pooftime.
Member Since: Posts: Comments:
Quoting keys33070:
What is the diffrence in the ensemble models and the computer models?


Ensemble models are computer models. The difference is that with ensemble models subtle changes are made to atmospheric (and other) conditions.
Member Since: March 10, 2006 Posts: 0 Comments: 11271
Uhh ohh. Dr. M used the "F" word in his blog... (Florida)
Member Since: March 10, 2006 Posts: 0 Comments: 11271
Thanks, Dr M

Yeah, it is a derived product, but the 850 mb divergence has a bit to do with dry air. Lower level divergence = sinking air = adiabatic heating = dry air there and layer(s) above.

One doesn't have to have a layer from Africa to have dry air.

This is a huge area of divergence very near a budding TS...not going to do Erika any favors.

Member Since: Posts: Comments:
......purdy.......
Member Since: Posts: Comments:
13. IKE
System just has too much going against it to be a major threat, wind wise. Biggest threat is heavy rains.

Just my unprofessional opinion.

Thanks Doc. Have a nice Wednesday!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Thanks Doctor.
Member Since: Posts: Comments:
.."I see Swirls,within Swirls"...


Member Since: July 3, 2005 Posts: 430 Comments: 131147

Viewing: 61 - 11

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 | 28Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

JeffMasters's Recent Photos

Carrot Nose in Danger
Deep Snow in Brookline, MA
Sunset at Fort DeSoto
New Years Day Sunset in Death Valley