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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McAfee tells me it blocked and removed a Trojan since I was here about 4 1/2 hours ago.
Member Since: Posts: Comments:
1310. IKE
Quoting NARCHER:
what a strange season you have a ts in the hurricane belt and have strong shear like were in july or nov. even the waves in e atl have fallen to the sear in the past week. am i correct?


So far...yes.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
I have been on here learning and lurking for years and I swear people on here are losing their minds, literally. they have gone off the deep end
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The naked swirl will be irrlevant soon IMO, the real circulation will be back by 59W
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Quoting Brillig:


Looks like Texas is saying, "Speak to the hand." (re post: 1194)


Lol. Would be fine with me if that "hand" stayed right where it is at least til December. :)
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Good Afternoon everyone! Looks like Erika is getting ready for DMIN to pull her usual, "I'm gonna blow up"!! She's actually beginning to look like a TS!! Comments??
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Quoting btwntx08:

what does that tell you


there is more than one circulation
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1301. Dakster
Quoting homelesswanderer:
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.


That is a characteristic of the virus, it won't let you use IE. It hasn't attacked FireFox....Yet.
Member Since: March 10, 2006 Posts: 0 Comments: 9713
1298. IKE
Quoting OSUWXGUY:


And when that dies we'll be back to an open wave... The Eastern Caribbean is a graveyard for weak systems as the low level flow is funneled through and accelerates...making it quite difficult for circulations to close off.

However, with an open wave this vigorous, it'll be worth watching over the coming days...especially if it heads due west and stays south of the islands.


Yeah, I'll be watching it too.

Guadeloupe airport recent reading....

"
Le Raizet Airport, GP (Airport)
Updated: 15 min 15 sec ago
Mostly Cloudy
84 °F
Mostly Cloudy
Humidity: 79%
Dew Point: 77 °F
Wind: 15 mph from the SSE
Pressure: 29.80 in (Steady)
Heat Index: 94 °F
Visibility: 6.2 miles
UV: 5 out of 16
Clouds:
Few 1600 ft
Scattered Clouds 4800 ft
Mostly Cloudy 23000 ft
(Above Ground Level)"


Hmmm...winds are now SSE. Center should now be west of there. Naked swirl appears to be at 16.0N and 62.0W as of 1845UTC.

Airport at 16.3N and 61.5W.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting kmanhurricaneman:
i totally disagree, i might go down in flames but i can take it the swirl or coc (claimed) under the convection is the false one look at the overall rotation on the loop and its plain as day.. man!!


then why is the vortex message not on that circulation??
Member Since: Posts: Comments:
Quoting Indialanticgirl:
Does anyone remember what service a member used last year to compare someones avatar with stock pictures used in advertising? Found out the blogger used some teen girls pix as his own? Tin something?


I was just wondering the same thing. I couldn't remember either.
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Quoting btwntx08:

incorrect the coc is is in the convection not the naked swirl thats false even drakoen said that naked swirl wasn't the center


Man you are boring!!!
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Quoting btwntx08:

incorrect the coc is is in the convection not the naked swirl thats false even drakoen said that naked swirl wasn't the center
i totally disagree, i might go down in flames but i can take it the swirl or coc (claimed) under the convection is the false one look at the overall rotation on the loop and its plain as day.. man!!
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1293. JLPR
getting more interesting =P

SFMR Peak (10s) Sfc. Wind:39 knots (~ 44.8 mph)

well removed from the center
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Recon is find west winds all the way to 58W as well, which is interesting
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Anyone have Erika’s eulogy ready?
Does anyone remember what service a member used last year to compare someones avatar with stock pictures used in advertising? Found out the blogger used some teen girls pix as his own? Tin something?
Member Since: Posts: Comments:
Quoting BoroDad17:
Flt Level Center is displaced 10 Nmi from Surface Center according to latest Vortex message update, what does that mean for Erika?


Same old same old. Still disorganized
1287. WXHam
img src="Next Week" alt="" />
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1286. JLPR
lol just saw this on Google Earth with the HHs

Corrected: This observation corrected a previously corrected observation.
xD
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1285. NARCHER
what a strange season you have a ts in the hurricane belt and have strong shear like were in july or nov. even the waves in e atl have fallen to the sear in the past week. am i correct?
Quoting antonio28:


Cape Verde


Thanks everyone. :)
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1283. Relix
Quoting AllStar17:
No matter where the center is, Erika will be WELL south of her next forecast point.

Be back in a few.

Will probably head to DR then.

See guys? My PR not getting hit forecast is almost true! XD!!!
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Quoting connie1976:
Floodman,

no, so that's good, right? lol


You sound fine to me. You would know if you had this particular virus. Just make sure you clear your history and cookies.
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1281. WXHam


Just in case you haven't noticed ... busy week next week?
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1279. jipmg
anybody have the radar form the islands
Member Since: Posts: Comments:
I got the same thing about two weeks ago - have avast and it took care of it completely. Had to shut down the program in the systems thingy (very technical term) and then run the virus checker in safe mode.
Member Since: Posts: Comments:
1277. IKE
Quoting btwntx08:

incorrect the coc is is in the convection not the naked swirl thats false even drakoen said that naked swirl wasn't the center


Wrong. Center fix according to recon was at 16.6N and 60.8W. Convection is east of there. There's very little at 16.6N and 60.8W.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
No matter where the center is, Erika will be WELL south of her next forecast point.

Be back in a few.
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Flt Level Center is displaced 10 Nmi from Surface Center according to latest Vortex message update, what does that mean for Erika?
Member Since: Posts: Comments:
BRB, getting a headache.. it might be a virus.
Member Since: October 1, 2007 Posts: 81 Comments: 26493
Quoting connie1976:
Floodman,

no, so that's good, right? lol


Exactly so...you have nothing to worry about for now...
Member Since: Posts: Comments:
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...


Connie I have to say too that I have run mine and only had a few bad cookies and nothing else... So if nothing came up then you should be ok.... Just becarful on what or who you click on....

Taco :0)
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Quoting IKE:


That's what I see too. I see no other spin.


And when that dies we'll be back to an open wave... The Eastern Caribbean is a graveyard for weak systems as the low level flow is funneled through and accelerates...making it quite difficult for circulations to close off.

However, with an open wave this vigorous, it'll be worth watching over the coming days...especially if it heads due west and stays south of the islands.
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1270. ssmate
Quoting JupiterFL:


Yes you have a virus.


You could of softened up that tough news a little. lol.
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Quoting connie1976:
Floodman,

no, so that's good, right? lol


lol
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1268. JLPR
....interesting
SFMR Peak (10s) Sfc. Wind:40 knots (~ 46.0 mph)

well to the SE of the center
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"We think Erika will miss the islands."....Everybody and their grandma said it!! I luv these weak little piss ant storms. Got'em all fooled. Erika is running da show****
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Quoting TexasHurricane:


What is CV?


Cape Verde
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Floodman,

no, so that's good, right? lol
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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...


You would know if you did. It cripples your computer with pop-up ads trying to sell you bogus anti-spyware and saying your computer is infected. If it is not a challenge to be here then most likely you do not have it.
Quoting Seastep:
Floodman - nice to meet you to.



Your avatar...is that Meteor Crater in Arizona?
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Cape Verde.
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About JeffMasters

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