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 apocalyps:
Never,ever in my lifetime i have seen such a blow up of convention.
Erika is almost in the Carribbean.
Is Texas in the carribbean?
Yeah,...Mon...The Texas Antilles...its irie mon...
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Quoting LPStormspotter:


Now how in someones mind could Troll= A State?
More like people..

Thanks,keep up the good work.
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Quoting antonio28:


456 Can we expect winds over 60MPH here in PR?


unlikely
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CMC is too aggressive with both the trough and Erika.
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Quoting btwntx08:

that naked coc in not the real center the real one is in the convection just east of the antielles


True, but I am wondering if that naked swirl could become a TD at some point if it slows down. I don't know -- just asking. It would not be the first time that I have seen a naked swirl produce a tropical cyclone.
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855. 789
Quoting stormno:
the nexy advisory ericka will be dowhgraded to a tropical depression and thats being generous..she is getting sheared all up...ERICKA IS WELL DONE YOU CAN STICKTHE FORK IN HER....Stormno
youre back great to hear from you
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Quoting TCIGolfer:
Question for Drak

What do you think of the GFDL intensification prediction. Last I saw was Cat 3 for GFDL just north of PR?


The GFDL has a strong tropical storm in the Bahamas.

I do not see the NHC making the system turn to the NW is their updated track instead I expect them to show a WNW motion pointing the cone towards Florida.
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did Dr. Masters ever post the storm surge maps he mentioned in a previous blog?
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Quoting apocalyps:
Never,ever in my lifetime i have seen such a blow up of convention.
Erika is almost in the Carribbean.
Is Texas in the carribbean?


you need help?
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Hmmmm, I seem to remember a system, i think that was similar track to this one! It was barely a TD when it made it over Cuba and then guess where it blew up? Your right, almost 30 years ago, 10 days from today, That little TD grew up to be a MONSTER called Fredric pounding Mobile Al!! You never know.
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Quoting Weather456:


windy and hot.


456 Can we expect winds over 60MPH here in PR?
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Quoting Drakoen:
GFDL takes Erika through the northeastern Caribbean and then has the system ending up in the southern Bahamas.

As far as the east coast is concerned, Florida is now a higher risk to receive potential impact from Erika whether it be or the form of a tropical wave or a tropical cyclone.


I somwhat concur with that statement based on the current model trends.
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847. JRRP
Quoting Weather456:


windy and hot.

ook..
Member Since: August 16, 2007 Posts: 0 Comments: 6213
Quoting Floodman:


Wow, was today a school holiday somewhere?


no, us kids just love to skip school
we look forward to our storm days.
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Flood - I plan on being tosspot this evening...HAHA Does that work -

Whats your opinion man - Erika going to make it to dmax?
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GFDL takes Erika through the northeastern Caribbean and then has the system ending up in the southern Bahamas.

As far as the east coast is concerned, Florida is now a higher risk to receive potential impact from Erika whether it be or the form of a tropical wave or a tropical cyclone.
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Quoting BurnedAfterPosting:


REad back, virus on the website

I never have issues like this with other sites


Did you get this "virus" on this site, or did you open a link from one of the posters?
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I've got anew Neighbor Uptown I see.

Actress Sandra Bullock purchases home in New Orleans' Garden District
by Rebecca Mowbray, The Times-Picayune



Tuesday September 01, 2009, 10:20 PM
AP Photo/Chris Pizzello

Actress Sandra Bullock, who has donated generously to Warren Easton Senior High School since Hurricane Katrina, has purchased a historic home in the Garden District from entrepreneur John Russell Lee Sr., whose I CAN Learn educational software was at the center of the Mose Jefferson trial.

Member Since: July 3, 2005 Posts: 428 Comments: 129833
Never,ever in my lifetime i have seen such a blow up of convention.
Erika is almost in the Carribbean.
Is Texas in the carribbean?
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is recon investigating erika if not when is the next flight
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Question for Drak

What do you think of the GFDL intensification prediction. Last I saw was Cat 3 for GFDL just north of PR?
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Quoting apocalyps:
What is a troll?
Are they living in Texas?
Just trying to learn here.


Now how in someones mind could Troll= A State?
More like people..
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I cant remember the last time a tropical cyclone like Erika dished out so many crow.
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Quoting SykKid:


Maybe...maybe not, Who cares? This storm is pathetic.


Wow, was today a school holiday somewhere?
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Quoting BurnedAfterPosting:


you feel she will survive 456?


I think she will survive in the near term but as for the long-term, not sure.


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Quoting RyanFSU:
The HyperCane WRF model (HWRF) for 12Z has erupted with a ridiculous intensity forecast for Erika. I am starting to question why this model is even run at this point.

A 60-hour forecast of a near Category 5 hurricane at 930 mb...come on.



I am not a meteorologist but I do not believe that is surface winds. Ask Drak or StormW or someone who know how to convert the Hpa number to surface wind knots.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting TheCaneWhisperer:


Hey, if your going to dish it, expect some in return. Just poking fun is all. Waters are around 31C between the Bahamas and the coast and shear may relax, you never know. I never pull cards off the table before the game is over.


I know dude just messing with ya...I know sst's are plenty warm just need upper conditions to cooperate and we might have something to watch in our backyard.
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Quoting RJT185:


Huh?


REad back, virus on the website

I never have issues like this with other sites
Quoting Weather456:


I've stated on my blog this morning and i feel Erika will deviate slightly left of the forecast cone (that was at 5am) due to 2 things:

her intensity is uncertain and she is being steered by building ridge. The trough may eventually pull her enough north at the end of the short-term forecast cycle but she could already reach the Bahamas.


At 11am, the cone did shift. Florida is not out of the woods yet.
thanks weather does it look like erika is getting her act together at this time
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Quoting Seflhurricane:
drak does it look like erika will last through the day


The system's center is exposed and the convection is unable to catch up to the low level circulation. The system could die. Cimss shear maps show an anticyclone south of the system and decreasing shear over the system. It is unclear whether or not Erika will survive but guidance from both the hurricane and the Global models indicate that Erika will overcome the adverse conditions. That remains to be seen.
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GOES-12 Atmospheric Imagery

These images are primarily for use in tropical storm monitoring. There are several areas to choose from providing a large-scale view of the Atlantic, down to the Gulf of Mexico. During hurricane season, the hurricanes page provides a variety of GOES atmospheric products to help monitor the active storms.
Member Since: July 3, 2005 Posts: 428 Comments: 129833
Quoting hurricane23:


Its ok...I already have my shutters up ready for the 15-20kt winds.
do you have your flashlights and batteries ready too

lol
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Quoting BurnedAfterPosting:
Yea Pat I am out of here and I hope some others follow suit

WU has done very very little to appease these issues, I was infected too and just got my computer up again. I am not going through this crap again; if WU cant get this under control; I advise many to find another site to visit.

To me its clear they dont care enough to make sure the site is safe.


Huh?
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Quoting JRRP:

what is the weather like 456?


windy and hot.
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now. but we have to watch for regeneration
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Quoting Weather456:


I've stated on my blog this morning and i feel Erika will deviate slightly left of the forecast cone (that was at 5am) due to 2 things:

her intensity is uncertain and she is being steered by building ridge. The trough may eventually pull her enough north at the end of the short-term forecast cycle but she could already reach the Bahamas.


At 11am, her has shifted.


you feel she will survive 456?
can someone explain to me how to tell which model runs are the most current? I don't know what time 00z, 12z, etc is. Thanks in advance!
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What is a troll?
Are they living in Texas?
Just trying to learn here.
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815. MahFL
I did a scan and it deleted it.
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Yea Pat I am out of here and I hope some others follow suit

WU has done very very little to appease these issues, I was infected too and just got my computer up again. I am not going through this crap again; if WU cant get this under control; I advise many to find another site to visit.

To me its clear they dont care enough to make sure the site is safe.
Quoting BurnedAfterPosting:


guess we will see, I feel she will survive

she also may regenerate plenty of warm water and time ahead of her
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Quoting Seflhurricane:
weather what is your opinion on erika at this time


I've stated on my blog this morning and i feel Erika will deviate slightly left of the forecast cone (that was at 5am) due to 2 things:

her intensity is uncertain and she is being steered by building ridge. The trough may eventually pull her enough north at the end of the short-term forecast cycle but she could already reach the Bahamas.


At 11am, the cone did shift. Florida is not out of the woods yet.
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Hey, keys33070, you asked me a while back what tosspot meant? It comes from middle English and means, pretty much, someone who is addled by drink...recently it's become synonomous with a wanker, who is addled by something else entirely

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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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