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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I think Erika will be a great lesson learned. NEVER TRUST A MODEL. Models are great conversation pieces but almost always change esp. when it is 3-5 days out. I think Erika will stall near the Florida coast then move out to sea.
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Quoting homelesswanderer:


Ok. Thank you. So kind of a reverse cold front. Lol.


not sure lol
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Quoting jpsb:

You are welcome, the difference in this blog between the day people and the night people is quite amazing! The day people are RIPers (she's done put a fork in her) and the night people are boosters (she'll be a hurricane next update). It is fun to watch. personally I think it is way to soon to RIP Erika. She is having a bad day as usual but there is still plenty of energy left in her and she seems to like the night much more then the day. let's see what she does tonight.


I agree... she's not been consistent with strengthening or dissipating thus far. I've just heard reports that southern Barbados suffered flooding from her so she's not going as quietly as we would like so far.
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Quoting tornadodude:

from AMS website: meridional front—A front in the South Pacific separating successive migratory subtropical anticyclones.
Such fronts are essentially in the form of great arcs with meridians of longitude as chords; they have the character of cold fronts. See polar trough.


Ok. Thank you. So kind of a reverse cold front. Lol.
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Erika will survive as a minimal TS or 50MPH for the next few days as she travel the NE caribbean nothing serious at this moment in term of winds for PR and the islands. =P :) Erikita we are waiting for you tiny little storm. LOL
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disagree
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Quoting tornadodude:
Also:
meridional front—A front in the South Pacific separating successive migratory subtropical anticyclones.
Such fronts are essentially in the form of great arcs with meridians of longitude as chords; they have the character of cold fronts. See polar trough.


ummmmm,ok.
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Quoting Patrap:


Front Hanging in with a Lil Kink Near the BOC..but its another Dry,Non-Humid Day in NOLA..

Wunderful weather again today


Could a cane get through that, or would it be sheared to bits?
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Quoting TexasHurricane:


Yes, please...anyone?


Meridional is along a meridian or North-South direction
Member Since: September 5, 2007 Posts: 0 Comments: 3488
Also:
meridional%u2014In meteorology, a flow, average, or functional variation taken in a direction that is parallel to a line of longitude; along a meridian; northerly or southerly; as opposed to zonal.
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i too think Erika will diminish, though one must wonder where in the Gulf it might end up if it stays on its current course and what results that might occur. I think it is a little too early to predict that aspect right now.
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"..WITH THE FRONTAL SURFACE TAKING ON A MORE MERIDIONAL
ORIENTATION AS IT ENTERS THE COASTAL WATERS."

If I had to guess, it means a north-south orientation (i.e., along meridians [longitude lines])
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Quoting DellOperator:


Yeah, and because of this I have steered clear of trying to forecast the track. I am focusing on more about the structure of the storm watching for a pronounced organization phase to set in. This has kept me less frustrated than most I have seen. I am not making any best guesses until I know the models can get a better handle on things with a definite tropical cyclone.


I'm with you 100%. I was surprised at how bearish the NHC was in its discussion and forecast intensity at 11AM.

Seems to me, we should still be in the wait and watch mode. The shear in the 200-300mb level doesn't seem to have a long lived cause (at least short term). The real westerlies won't be impacting Erika until between 60 and 72 hours according to SHIPS.

This still gives it the opportunity to become better organized. Whether it will or won't is pretty much a coin flip...

SHIPS Guidance Erika 12UTC
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Quoting PensacolaDoug:
How many "Caster" variations are there?

1. Wishcaster
2. Downcaster
3. West North South and east....
4. RIPcaster
5. NOLAcasters
6. Disastercasters (my personal fave)
7. Flordiacasters

just to name a few...

The most overused thing here...

I think we need to be careful not to forget the term dumbcaster. I would hate for it to be lost from our lexicon.

Addendum: Speak of the devil and he gets referenced...
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Quoting divdog:
stormno

coming from a guy who said it would never become a TS. Credibility is at an all time low.


If this is the same guy as stormkat, he also had major problems with the Dean track a few years ago.

So if stormno is predicting the death of Erica, then it's time for me to start boarding up my windows and packing the car.
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"You are welcome, the difference in this blog between the day people and the night people is quite amazing! The day people are RIPers (she's done put a fork in her) and the night people are boosters (she'll be a hurricane next update). It is fun to watch. personally I think it is way to soon to RIP Erika. She is having a bad day as usual but there is still plenty of energy left in her and she seems to like the night much more then the day. let's see what she does tonight."

The bloggers follow diunral cycles.

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I still think Erika will make it into the Craibbean & become a powerful hurricane.
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forgot doomcaster
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Quoting southfla:
There is also this web site for sounding data in the Caribbean -- Choose the Caribbean link on the left side of the page. I never saw this web site before -- they have some really nice analysis plots.

Another good source, thanks.
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Quoting TexasHurricane:


Yes, please...anyone?

from AMS website: meridional front—A front in the South Pacific separating successive migratory subtropical anticyclones.
Such fronts are essentially in the form of great arcs with meridians of longitude as chords; they have the character of cold fronts. See polar trough.
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or purple
Member Since: December 9, 2008 Posts: 0 Comments: 2498
How many "Caster" variations are there?

1. Wishcaster
2. Downcaster
3. West North South and east....
4. RIPcaster
5. NOLAcasters
6. Disastercasters (my personal fave)
7. Flordiacasters

just to name a few...

The most overused thing here...
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Quoting louisianaboy444:
Just checking in and Erika is looking bad i aint surprised that the NHC is calling for possible death of this system...shear looks to be quite harsh over the coming days
Hi Laboy444, Hope you are correct. I have no educated guess or clue. Dr. Masters did say that the shear environment was complicated so I'll definitely keep watching.
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I guess I'm moody

I can share some of my hormones, but they might make you want to go shopping and paint your toenails hot pink...

:)
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Quoting homelesswanderer:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
629 AM CDT WED SEP 2 2009

SYNOPSIS...

THE MIDWEST HIGH WILL BUILD FURTHER SOUTH ACROSS THE WESTERN GULF
OF MEXICO TODAY...DISTORTING A STATIONARY FRONT...WHICH CURRENTLY
EXTENDS THROUGH CENTRAL FLORIDA TO MARINE POINT 26N 87W TO JUST
SOUTH OF BROWNSVILLE. THE WESTERN SEGMENT OF THE FRONTAL SURFACE
WILL ADVANCE FURTHER SOUTH INTO THE BAY OF CAMPECHE...WHILE THE
EASTERN HALF MOVES LITTLE.

THE BERMUDA HIGH WILL RE-BUILD ACROSS SOUTH FLORIDA ON FRIDAY...
FURTHER DISTORTING THE FRONTAL SURFACE...WHICH WILL BE FOUND NEAR
A LINE FROM JUST OFFSHORE GEORGIA TO MARINE POINT 28N 90W TO
MARINE POINT 24N 95W.

THE WESTERN SEGMENT OF THIS POSITIVE-TILTED FRONTAL SURFACE WILL
ADVANCE NORTH AND WEST THROUGH THE GULF OF MEXICO OVER THE WEEKEND
..WITH THE FRONTAL SURFACE TAKING ON A MORE MERIDIONAL
ORIENTATION AS IT ENTERS THE COASTAL WATERS.


In English, anyone?? Please. :)


Yes, please...anyone?
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Thanks Pat. How is the new puppy doing??
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Looks like Erika is going to be nothing like her deadbeat sis Ana and bro Danny. Look at the dry air that surrounds her on WV. A combination of dry air and strong shear will be turning Erika into a wave pretty soon. I will give her credit. She did try her best with the cards she was dealt.
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Quoting jpsb:


You are welcome, the difference in this blog between the day people and the night people is quite amazing! The day people are RIPers (she's done put a fork in her) and the night people are boosters (she'll be a hurricane next update). It is fun to watch. personally I think it is way to soon to RIP Erika. She is having a bad day as usual but there is still plenty of energy left in her and she seems to like the night much more then the day. let's see what she does tonight.


i know exactly what you mean, makes very hectic in the late afternoon when the RIPers and "boosters" are on simotaneously
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Quoting SQUAWK:
What's up in the GOM Pat?


Front Hanging in with a Lil Kink Near the BOC..but its another Dry,Non-Humid Day in NOLA..

Wunderful weather again today
Member Since: Posts: Comments:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
629 AM CDT WED SEP 2 2009

SYNOPSIS...

THE MIDWEST HIGH WILL BUILD FURTHER SOUTH ACROSS THE WESTERN GULF
OF MEXICO TODAY...DISTORTING A STATIONARY FRONT...WHICH CURRENTLY
EXTENDS THROUGH CENTRAL FLORIDA TO MARINE POINT 26N 87W TO JUST
SOUTH OF BROWNSVILLE. THE WESTERN SEGMENT OF THE FRONTAL SURFACE
WILL ADVANCE FURTHER SOUTH INTO THE BAY OF CAMPECHE...WHILE THE
EASTERN HALF MOVES LITTLE.

THE BERMUDA HIGH WILL RE-BUILD ACROSS SOUTH FLORIDA ON FRIDAY...
FURTHER DISTORTING THE FRONTAL SURFACE...WHICH WILL BE FOUND NEAR
A LINE FROM JUST OFFSHORE GEORGIA TO MARINE POINT 28N 90W TO
MARINE POINT 24N 95W.

THE WESTERN SEGMENT OF THIS POSITIVE-TILTED FRONTAL SURFACE WILL
ADVANCE NORTH AND WEST THROUGH THE GULF OF MEXICO OVER THE WEEKEND
..WITH THE FRONTAL SURFACE TAKING ON A MORE MERIDIONAL
ORIENTATION AS IT ENTERS THE COASTAL WATERS.


In English, anyone?? Please. :)
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There is a pinguin swimming north and ERIKA is not....i repeat NOT following him.
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276. IKE
Quoting BobinTampa:



I've seen Ike called a downcaster and a wischcaster on the same storm - about 5 hours apart!!



I guess I'm moody.
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275. jpsb
Quoting midgulfmom:
Thank you for that fine explanation. Makes sense to me.


You are welcome, the difference in this blog between the day people and the night people is quite amazing! The day people are RIPers (she's done put a fork in her) and the night people are boosters (she'll be a hurricane next update). It is fun to watch. personally I think it is way to soon to RIP Erika. She is having a bad day as usual but there is still plenty of energy left in her and she seems to like the night much more then the day. let's see what she does tonight.
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which one???
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Quoting rwdobson:


I meant the "Miami–Fort Lauderdale–Pompano Beach Metropolitan Area" as defined by the Census.

But you basically made my point anyway. "Miami" may only have 500,000, but including all of Dade you get to 2.3 million.


That is correct, but those cities are in several Florida Counties. And yes, I see the point you were trying to make. City of Miami is the largest City in Miami-Dade County, but more than half of the residents of the county live outside of the City of Miami.
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264. SQUAWK 8:32 AM PDT on September 02, 2009
What's up in the GOM Pat?


it's missing my purple hippo, that's what's up!
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Quoting IKE:


I won't. Some will call you a downcaster. I've been labeled that a few days ago.

You're entitled to your opinion.



I've seen Ike called a downcaster and a wischcaster on the same storm - about 5 hours apart!!

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Just checking in this morning...

I see we lost our yellow circle.... I thought this was September, the most active month of hurricane season where everything develops into something.... :)
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Quoting atmoaggie:

Dang, I spent some time looking for this. Thanks for putting it up! (forgot all about the Wyoming sounding page)


No problem. Paging through the old rap.ucar sight and found it.

This kind of failure on the parts of the models to recognize/resolve shear better will put a lid on how much better these models can get...

Somehow, someway we need to be able to get better upper air data over the oceans. The G4 around a storm is a start, but there needs to be a more permanent, ongoing solution.
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There is also this web site for sounding data in the Caribbean -- Choose the Caribbean link on the left side of the page. I never saw this web site before -- they have some really nice analysis plots.
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nope
Member Since: December 9, 2008 Posts: 0 Comments: 2498
I smell college football in the air!
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Quoting Dakster:


Wrong. Miami-Dade has about 2.3 Million. If you include Broward and West Palm Beach you will get 5.5 Million...


I meant the "Miami–Fort Lauderdale–Pompano Beach Metropolitan Area" as defined by the Census.

But you basically made my point anyway. "Miami" may only have 500,000, but including all of Dade you get to 2.3 million.
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What's up in the GOM Pat?
Member Since: December 9, 2008 Posts: 0 Comments: 2498
Quoting louisianaboy444:
There's no such thing as a downcaster it is just a word made up by wishcasters for the forecasters that actually tell the truth


How about nowcaster, seems appropriate. Don't think I would drive the final nail but she's a struggling that is for sure. Many notables have come from what seemed to be doomed tropical entities. A week is a really long time to predict.
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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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