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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1361. OracleDeAtlantis
2:36 AM GMT on September 03, 2009
Am I correct in that this blocked false trojan experienced today is also responsible for blocking the scripting on this blog? I can't quote or show a hidden post.
Member Since: August 27, 2009 Posts: 0 Comments: 524
1360. Brillig
11:10 PM GMT on September 02, 2009
I have an idea for visualizing the storm center. Take HH data and plot lines perpendicular to the normal flags. Make the length of the lines be proportional to the wind speed. The result will look something like this. The lines all point to the center of circulation.
Storm Center Visualization

Multiple centers and insignificant vortexes should be evident this way.
Member Since: June 23, 2006 Posts: 20 Comments: 408
1359. CaribBoy
9:45 PM GMT on September 02, 2009
looks like a new center is developing just east of the northern leewards.... slightly north and east (17.7N 60.5W) of the official one.
Member Since: October 6, 2007 Posts: 0 Comments: 6168
1358. aspectre
9:19 PM GMT on September 02, 2009
1355. cirrocumulus "Erika is still headed southwest"

Advisory 1 to 1a
21GMT 09/01/09 17.2N 57.3W
00GMT 09/02/09 17.2N 57.3W
0north to 0south ... Stationary

Advisory 1a to 2
00GMT 09/02/09 17.2N 57.3W
03GMT 09/02/09 17.5N 57.6W
3north to 3west ... InvTan(3/3/cos17.5) = 46.357degrees north of W
heading 1.357degrees north of NW

Advisory 2 to 2a
03GMT 09/02/09 17.5N 57.6W
06GMT 09/02/09 17.0N 58.7W
5south to 11west ... InvTan(5/11/cos17) = 25.42degrees south of W
heading 2.92degrees south of WSW

Advisory 2a to 3
06GMT 09/02/09 17.0N 58.7W
09GMT 09/02/09 17.0N 59.0W
0north to 3west ... due West

Advisory 3 to 3a
09GMT 09/02/09 17.0N 59.0W
12GMT 09/02/09 16.5N 59.5W
5south to 5west ... InvTan(5/5/cos16.5) = 46.2degrees south of W
heading 1.2degrees south of SW

Advisory 3a to 4
12GMT 09/02/09 16.5N 59.5W
15GMT 09/02/09 16.5N 60.4W
0north to 9west ... heading due West

Advisory 4 to 4a
15GMT 09/02/09 16.5N 60.4W
18GMT 09/02/09 16.2N 61.1W
3south to 7west ... InvTan(3/7/cos16.2) = 24.05degrees south of W
heading 1.55degrees south of WSW

Advisory 4a to 5
18GMT 09/02/09 16.2N 61.1W
21GMT 09/02/09 16.4N 61.7W
2north to 6west ... InvTan(2/6/cos16.4) = 19.16degrees north of W
heading 3.34degrees west of WNW

Still jitterbugging through LARGE changes in its heading... ?mostly center relocations?
Member Since: August 21, 2007 Posts: 0 Comments: 4860
1357. hydrus
8:57 PM GMT on September 02, 2009
Quoting RJT185:


How much?
Rem
Quoting cybergrump:
The HWRF is scary. It intensifies it.
The HWRF is not good at predicting intensity.
Member Since: September 27, 2007 Posts: 1 Comments: 21183
1356. cirrocumulus
8:48 PM GMT on September 02, 2009
Be careful on this website. McAfee is continually having to block and remove a trojan.
Member Since: September 30, 2005 Posts: 0 Comments: 1606
1355. cirrocumulus
8:44 PM GMT on September 02, 2009
Erika is still headed southwest.
Member Since: September 30, 2005 Posts: 0 Comments: 1606
1354. NARCHER
8:12 PM GMT on September 02, 2009
cchs what do you make of recon data?
looks like a new center is forming close to the stronger ts?
1352. NARCHER
7:51 PM GMT on September 02, 2009
keep us informed............
1351. StadiumEffect
7:49 PM GMT on September 02, 2009
Quoting JLPR:
Does this mean it will down graded @ 5

im thinking we might have a depression but it could make a comeback tomorrow

As long as we have winds >39mph and a closed low of some kind (even if relatively broad with multiple voticies present) it will still be classed as a TS.
1350. kmanhurricaneman
7:41 PM GMT on September 02, 2009
Quoting IKE:


On this blog? I think about 5% never had it. And I'm not saying that pertains to anyone on here now, specifically. Heck, I may not have it.

I looked at some buoys east of Guadeloupe and most of them don't report winds, BP, etc.

Here's one at 14.6N and 56.2W and they haven't reported west winds in the last 24 hours! Granted Erika is/was, NW of there, but they should have had west winds at some point!

Unless the circulation is just so small, but that buoy wasn't over 100 miles from where Erika's center was at.
mmmmmmmm...!!
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1349. goavs4
7:43 PM GMT on September 02, 2009
Quoting Floodman:


Footage from the Mars rover?


Actually it is, Victoria crater as imaged by the rover Opportunity
Member Since: September 7, 2007 Posts: 0 Comments: 72
1348. Chiggy007
7:41 PM GMT on September 02, 2009
18Z BAM models are now even futher south and west....
1346. IKE
7:39 PM GMT on September 02, 2009
Quoting kmanhurricaneman:
IKE, is it me or has most every one lost it!!


On this blog? I think about 5% never had it. And I'm not saying that pertains to anyone on here now, specifically. Heck, I may not have it.

I looked at some buoys east of Guadeloupe and most of them don't report winds, BP, etc.

Here's one at 14.6N and 56.2W and they haven't reported west winds in the last 24 hours! Granted Erika is/was, NW of there, but they should have had west winds at some point!

Unless the circulation is just so small, but that buoy wasn't over 100 miles from where Erika's center was at.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1344. MTCseadrifter
7:37 PM GMT on September 02, 2009
If the naked center was false, wouldn't it be rotating around the real center instead of stalling? IMO the naked swirl is the LLC. The storm is tilted and maybe fixing to decouple.
Member Since: July 28, 2007 Posts: 0 Comments: 260
1343. whitewabit (Mod)
7:37 PM GMT on September 02, 2009
theres is no such thing as a false COC !!!
Member Since: August 17, 2005 Posts: 362 Comments: 31373
1340. cchsweatherman
7:36 PM GMT on September 02, 2009
Been keeping an eye on and analyzing the Hurricane Hunter Recon data and it appears that we will very likely see a rather dramatic relocation with Tropical Storm Erika's center. With the data still showing SSW winds at around 15N and 58W, it appears that the circulation center exists underneath the convection.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
1339. Floodman
7:36 PM GMT on September 02, 2009
Quoting Seastep:
1263. Floodman 3:15 PM EDT on September 02, 2009 Hide this comment.

Quoting Seastep:
Floodman - nice to meet you to.



Your avatar...is that Meteor Crater in Arizona?

-- end quote --

Nope. When I first uploaded it last year, it was slow and we played "guess the avatar."

No one has been able to guess it so far.

Interesting that recon climbed up to 5K feet from 1300. Must be pretty rough out there.


Footage from the Mars rover?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
1338. Becca36
7:36 PM GMT on September 02, 2009
Quoting justalurker:


bye bye..see you in 95 hrs

Please don't quote the bad comments. TY
Member Since: June 26, 2009 Posts: 0 Comments: 162
1337. Seastep
7:35 PM GMT on September 02, 2009
1263. Floodman 3:15 PM EDT on September 02, 2009 Hide this comment.

Quoting Seastep:
Floodman - nice to meet you to.



Your avatar...is that Meteor Crater in Arizona?

-- end quote --

Nope. When I first uploaded it last year, it was slow and we played "guess the avatar."

No one has been able to guess it so far.

Interesting that recon climbed up to 5K feet from 1300. Must be pretty rough out there.
Member Since: September 9, 2008 Posts: 6 Comments: 3414
1336. SQUAWK
7:35 PM GMT on September 02, 2009
Hey kids, guess what??

NEW BLOG!!!
NEW BLOG!!!
NEW BLOG!!!
NEW BLOG!!!
Member Since: December 9, 2008 Posts: 0 Comments: 2498
1335. whitewabit (Mod)
7:34 PM GMT on September 02, 2009
Lesser Antillies Radar... http://www.meteo.fr/temps/domtom/antilles/pack-public/animation/animMOSAIC2.html

you can see a coc west of the islands when you animate it...
Member Since: August 17, 2005 Posts: 362 Comments: 31373
1334. TexasHurricane
7:34 PM GMT on September 02, 2009
Quoting homelesswanderer:


Lol. Would be fine with me if that "hand" stayed right where it is at least til December. :)


yeah, but wonder if it is waiting for something to get there and then we will be like, where's the Texas hand.....
Member Since: July 2, 2009 Posts: 0 Comments: 2811
1333. Floodman
7:34 PM GMT on September 02, 2009
seminolesfan, you have mail!

Member Since: August 2, 2006 Posts: 10 Comments: 9922
1332. homelesswanderer
7:34 PM GMT on September 02, 2009
Quoting Dakster:


That is a characteristic of the virus, it won't let you use IE. It hasn't attacked FireFox....Yet.


Oh. Ok. Thanks. I'll check for it then. Hubby got something other night kept restarting his computer over and over. We got it fixed but now his Toshiba thinks its a Dell. Lol.
Member Since: August 15, 2008 Posts: 10 Comments: 3665
1331. butterballlove
7:34 PM GMT on September 02, 2009
indiatlanticgirl, you have mail... new blog up
1329. TheCaneWhisperer
7:32 PM GMT on September 02, 2009
With competing circulations the dry air and shear are doing their best to turn this into an open gale.
1328. kmanhurricaneman
7:32 PM GMT on September 02, 2009
IKE, is it me or has most every one lost it!!
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1327. CaribBoy
7:32 PM GMT on September 02, 2009
Quoting BurnedAfterPosting:
The naked swirl will be irrlevant soon IMO, the real circulation will be back by 59W


AGREED
Member Since: October 6, 2007 Posts: 0 Comments: 6168
1326. 92Andrew
7:32 PM GMT on September 02, 2009
I am not at all shocked as to what is happening with TS Erika. Her chances were blown when she did not develop three days ago. Most on this blog tend to take the doomsday scenario... and it is annoying. Storm tracking and prediction is not about feeding into your passions and hoping for whatever it is you want, instead, it is about thinking in terms of patterns and with the facts. For TS Erika, she is more likely to die than to intensify. That is a fact. Look at her exposed coc, and the numbers, with the level of shear being the most indicative. She has little chances for survival, and i expect this thing to die off before she becomes a threat to CONUS. Expect her to dissipate... and expect all eyes getting focused with the wave currently coming out of Africa after Erika's death becomes indisputable.
Member Since: July 27, 2009 Posts: 0 Comments: 96
1325. BoroDad17
7:32 PM GMT on September 02, 2009
Another Newbie question, but I noticed some convection flaring up in the latest RGB frames on the naked swirl that is a false center... I do still see the circulation in the main convection as well. What are the chances of Erika spawning a second TC?
Member Since: September 5, 2008 Posts: 0 Comments: 125
1324. WINDSMURF
7:31 PM GMT on September 02, 2009
Ladies and Gentlemans, Erika has become so difficult to forecast; that I'm beginning to believe that our only hope for an accurate forecast will have to come from JFV/WS. What do you guys think?
Member Since: August 10, 2009 Posts: 0 Comments: 167
1323. jipmg
7:31 PM GMT on September 02, 2009
Quoting IKE:


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.


but the hunters are reporting WEST WINDS at 58W
1322. stormpetrol
7:31 PM GMT on September 02, 2009
The old clear to see LLC is at 16N/62W at present, looking more vigorous too I might add, the other possible competing COC looks to be at 15.3N/59.8W, jmo. We'll have go by what the HHs say they know what their doing, plus they have the advantage of surveying the whole area.
Member Since: April 29, 2007 Posts: 0 Comments: 7862
1321. connie1976
7:31 PM GMT on September 02, 2009
Quoting CaneHunter031472:


El Niño and the fact that this summer has been unseasonably cool. So in conclusion it is global warming and people driving SUVs fault. :o)


lol.....
Member Since: September 1, 2008 Posts: 0 Comments: 672
1320. kmanhurricaneman
7:30 PM GMT on September 02, 2009
Quoting TheCaneWhisperer:
Glad I don't have a job tied to this storm and can walk away from time to time, lol.

This would drive me nuts, I'd be praying for the end of my shift.
AMEN!
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1319. CaneHunter031472
7:30 PM GMT on September 02, 2009
Quoting IKE:


So far...yes.


El Niño and the fact that this summer has been unseasonably cool. So in conclusion it is global warming and people driving SUVs fault. :o)
Member Since: August 1, 2007 Posts: 0 Comments: 179
1318. reedzone
7:29 PM GMT on September 02, 2009
Quoting BurnedAfterPosting:
The naked swirl will be irrlevant soon IMO, the real circulation will be back by 59W


According to Dr. Masters, it's a fake swirl lol. I see Erika pushing through some 20-30 knots of wind shear tomorrow but then heads for another Anticyclone near the Bahamas, and strengthens. Flat out prediction right there.. We just don't really know what's gonna happen.
Member Since: July 1, 2008 Posts: 13 Comments: 7387
1317. TheCaneWhisperer
7:31 PM GMT on September 02, 2009
Glad I don't have a job tied to this storm and can walk away from time to time, lol.

This would drive me nuts, I'd be praying for the end of my shift.
1314. Patrap
7:28 PM GMT on September 02, 2009
Ive recieved some mail in regards to My feelings as to Presidents Bush Failure to Land here 4 Years ago today as many were still being pulled from the Katrina FLoodwater's here.

I personally watched him Orbit and sail off to the Neast 4 years ago..and that moment was the Lowest in my 45 years at that time.

Here is my Response in Kind as to How a Real President Handled the same Situation 40 years ago.

Some may find the scenes and words,er,
"Vary" interesting...and very ironic.

Hurricane Betsy, LBJ and the Dixiecrats: The Politics of New Orleans Flooding

Patrick
Member Since: July 3, 2005 Posts: 424 Comments: 128259
1313. Relix
7:27 PM GMT on September 02, 2009
Quoting robinvtx1215:
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


Erika does that. =P
Member Since: August 3, 2006 Posts: 0 Comments: 2722
1312. Joshfsu123
7:27 PM GMT on September 02, 2009
Quoting btwntx08:

what does that tell you



Tells me there is a broad center of circulation with llc swirling around in a broader center.... as the NHC has stated.
Member Since: July 6, 2005 Posts: 5 Comments: 580
1311. BonInBama
7:27 PM GMT on September 02, 2009
McAfee tells me it blocked and removed a Trojan since I was here about 4 1/2 hours ago.

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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.