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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stormno

coming from a guy who said it would never become a TS. Credibility is at an all time low.
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Rain fields are consolidating.
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Quoting Dakster:


LOL.... At leasr you spelled HEBERT correct. Although I disagree that is voodoo... It seems to be backed up by some pretty decent historical fact. (Not that 150 years of data is really historical for the EARTH).

Although, Floodman can probably fill in the missing several thousand years - since he said he remembers when dirt was new and dinos roamed the Earth...



Well sport,Im a Cajun and Bobby Hebert was a Saint for MAny years..

I got Boxed with Him once ..

LOL
Member Since: July 3, 2005 Posts: 426 Comments: 128667
Quoting stormno:
ericka is biting i to some big time shear and its only going to get worse guys i cant see how you didnt see this yesterday...you guys really just wishcast ..you need to start looking at reality ERICKA WILL BE SUCKED UP LIKE A VACCUUM..LONG LIVE ERICKA..I THINK THAT MAKES ME 5 FOR 5 THIS YEARS GUYS..Stormno

go watch the gulf for us !
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Well, once again lots of uncertainty. Since things have been quiet in the GOM for the most part this year, I have tapped into my beer reserve. If there is a change Erika could come for a visit here, let me know if I should replenish.

Oh, Pat - got berled shrimp at the drive-thru? lol
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mornin'....

:)
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stupid question: What is D Max?
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Quoting rxse7en:
Diurnal Min and Max.


i thought D-max was in the morning and D-min at night?
im probably wrong
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Quoting rwdobson:


Considering how insightful and accurate your forecasts were for Bill, we should all pay close attention to you! You were dead on with your predictions of a disastrous late evacuation on the east coast.


Well i did say Bill would make the big turn on friday three days before it did.
But hey,who does not shoot can not mis.
And there is nothing to win or loose on this blog.So who cares who is wright or wrong?
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Quoting Patrap:
..Bueller?..Ferris Bueller?..


Okay Class,todays subject will be,voodoo,er.
.. Hebert,Hebert?

..Voodoo Meteorology 101,or Hebert Boxe's


For those of you who do not know:

While these boxes provide an indication that a hurricane may threaten South Florida, a hurricane does not have to pass through one to strike there, as were the case with the Labor Day Hurricane of 1935 and Hurricane Andrew, though the latter did skirt the edges of the eastern box. Additionally, a hurricane which does pass through a Hebert Box can very easily miss Florida, or indeed any landfall entirely. Hebert himself acknowledged that the boxes are not a guarantee of hurricane landfall either way, but cautions that if a hurricane passes through one, "really, really pay attention. We worry plenty in August and September when one goes through that box, and we have a certain comfort level when one misses the box."

Hebert Boxes are good for looking back, as in "Wow, that one went through the box!", but when one goes through the box and misses, no one says "Wow, it went through the box and didn't make landfall!"
Member Since: August 2, 2006 Posts: 10 Comments: 9922
the track should have been kept as a minimal tropical storm the whole time if there so uncertain with the intensity , but the track should be shifted southward between the 2 camps of models and i truthfully think the southern camp will be the track but over more water. just my opinion
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It is quite funny to watch the cycles this blog takes:
Early Morning until around 6pm- RIP Erika.
6pm until Early Morning- Hurricane.
crazy :P
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Quoting BrockBerlin:


? BrockBerlin understands the Evangel (where the real BrockBerlin went to high school) part but what part of that post was childish?


The 3rd person stuff
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Quoting Patrap:
..Bueller?..Ferris Bueller?..


Okay Class,todays subject will be,voodoo,er.
.. Hebert,Hebert?

..Voodoo Meteorology 101,or Hebert Boxe's


LOL.... At leasr you spelled HEBERT correct. Although I disagree that is voodoo... It seems to be backed up by some pretty decent historical fact. (Not that 150 years of data is really historical for the EARTH).

Although, Floodman can probably fill in the missing several thousand years - since he said he remembers when dirt was new and dinos roamed the Earth...
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As compared to intensity models for Jimena. Only everyone's beloved UKMET seems to have substantially missed the mark.

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Quoting tropicalmommie:


I also have lived in the Keys for years and was evacuated for Wilma. Being surrounded by water I take no storm "lightly"



I have heard many stories from people who stuck around for Wilma. I have a friend who said her and her husband were fishing from their window and caught a bull shark in their back yard. I can honestly say I am glad I was not around for that one!
Quoting tornadodude:


seems like Erika wekens during the day, then explodes around 8 pm, weird...
Diurnal Min and Max.
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New Drama Series: "As Erika spins - the unpreditable like of Erika Cane.
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Quoting tornadodude:


seems like Erika wekens during the day, then explodes around 8 pm, weird...

Isn't that when D-Max starts?
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138. eddye
it looks more likely that se fl could get hit by a ts or a not a minium hurricane
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Quoting Michfan:


Its not that were discounting her moving SW it is the fact that we've been saying that her center relocated to a different location. One needs to be careful when classifying a center reformation in relation to what is a true movement over a 6 hour period. If you look at what the original center initialization was from yesterday it continued to the west.


As the even the Doc stated the center is reforming to the SW of where it was yesterday. The NHC has a handle on where the actual center is and if you plot their coordinates it's movement was SW and not W, this includes the newest coordinates they have pegged under the new reforming center. Several people were stating that it did not move SW and that it was an illusion, plotted coordinates prove them to be wrong. My facts are based on the official NHC track, not hear say.
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Hah! Intensity models are blindfolded and wandering a cornfield.

40 knots to 140 knots or maybe somewhere in between. Ok, thanks. Conundrum solved.

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Quoting btwntx08:

agreed
it is also possible we may not need a cone musch longer. looks really unimpressive.
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..Bueller?..Ferris Bueller?..


Okay Class,todays subject will be,voodoo,er.
.. Hebert,Hebert?

..Voodoo Meteorology 101,or Hebert Boxe's
Member Since: July 3, 2005 Posts: 426 Comments: 128667
Quoting keys33070:
I have lived in the Keys for almost 4 years and I have yet to see anything to get bothered over. Last year they had a mandatory evac for all visitors, what a joke. We sat and laughed at the news crews filming the slight movement of palm leaves, and tipping trash cans.


I also have lived in the Keys for years and was evacuated for Wilma. Being surrounded by water I take no storm "lightly"
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Quoting apocalyps:
Drifting to the carribbean.
Track forecast is so wrong.
No reason for Erica to turn NW.
It is just drifting.
So it will not feel any weakness.


Considering how insightful and accurate your forecasts were for Bill, we should all pay close attention to you! You were dead on with your predictions of a disastrous late evacuation on the east coast.
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Drifting to the carribbean.
Track forecast is so wrong.
No reason for Erica to turn NW.
It is just drifting.
So it will not feel any weakness.
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Quoting dolphingalrules:
the herbert #1 is right there..i give it 6 hrs


Remember the rules though: Storms stronger than a CAT 1. Anything below that and all bets are off
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting midgulfmom:
LOL, or needs some counseling.


do you want a shot at it?..lol
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Wow did Jimena ever weaken fast ... that is weird since the water isn't really that cool 27 - 28 C

Waves from Africa look impressive
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Quoting jasoniscoolman10:
WINDS AT 11AM 40 MPH.
the herbert #1 is right there..i give it 6 hrs
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Quoting atmoaggie:

sarcasm: Yeah. I heard the same thing around NOLA up until 4 years ago. Goofy people fleeing a big thunderstorm.
Not sarcasm: Please don't risk the lives of rescue personnel when it happens. Just go quietly.


Yep.
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Based on the 11AM advisory many will prematurely write her off. Personally, I think she still has a trick or two up her sleeve.
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Quoting apocalyps:


She is playing hard to get.
LOL, or needs some counseling.
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Quoting IKE:
5 day weakens it to a depression....

Cone is wrong. They don't know how to make one when path is highly uncertain. It very well may bust it again.
Member Since: August 10, 2007 Posts: 0 Comments: 3274
Quoting DestinJeff:
IT WOULD NOT BE SURPRISING IF ERIKA DISSIPATED.............

that alsmost guarantees strong TS by the 5PM adv


seems like Erika wekens during the day, then explodes around 8 pm, weird...
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Quoting weatherneophyte:
Patrap, #38, great satellite capture. Where did you find that?


ALL NOAA Floater Imagery
Member Since: July 3, 2005 Posts: 426 Comments: 128667
116. jpsb
Quoting truecajun:


i don't think this front is going to hold past friday. they never hold that long this early in "fall" I'm not saying it's going to enter GOM, but I don't think the front will last much longer.
I'm surprised it's held this long! But even after the front lifts the trof will still be around protecting the GoM. If you are on the GoM, the thing to watch is that HUGE trof on the east coast. When that goes away then CV storms have a chance of reaching the GoM.

Now if I were gulfcasting, lol, I say that since Erika is not stacked, (circulation wise that is, lol) she remains unorganized and she might just slide under the upper level steering currents (trof as it lifts and moves east) and continues slowly west, maybe even a little south of west. Then she organizes and makes it into the GoM after the front has lifted.

the above is not likely as Erika is bond to become better organized and the trof is exceptionally strong. Any movement north makes interaction with that trof more certain. Any interaction with Island mountains will likely rip a weak T.S. like Erika apart. So if Erika stays weak and continues west the islands will get her. If the gets strong and goes more north the trof will get her. Shes got one hard road ahead of her if she wants to get into the nice warm gulf waters.

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115. IKE
Quoting btwntx08:

i don't expect that so no next


Based on what I just read from the NHC, I think it's a 50-50 chance of being sheared to death within 48-96 hours.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting TriniGirl26:
the old people have a saying in trinidad. No one can tell a hurricane where to go and where not to go. they have a mind of their own and will do anything they feel like doing...Let it be. All you can do is prepare.


And there you have it...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting TriniGirl26:
the old people have a saying in trinidad. No one can tell a hurricane where to go and where not to go. they have a mind of their own and will do anything they feel like doing...Let it be. All you can do is prepare.


very insightful
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They are still seeing the dry air:
500mb RH in color shading shows less than 50% RH all around Erika.

Could have made it easier on y'all and put up that the RH plot is the 06 Z GFS nowcast. Sorry.
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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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