Dr. Jeff Masters' WunderBlog

Tropical Storm Erika's future highly uncertain
Posted by: Dr. Jeff Masters, 2:21 PM GMT on September 02, 2009 +2
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
Categories: Hurricane
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1101. Orcasystems 6:37 PM GMT on September 02, 2009    
Member Since: October 1, 2007 Posts: 77 Comments: 26077
1102. hurricanehanna 6:37 PM GMT on September 02, 2009    
1094. Squak - nope, no ads.

Quote feature doesn't work either. I've run everything. It's only hitting from this site.
Member Since: September 5, 2007 Posts: 0 Comments: 3214
1103. bocahurricane 6:37 PM GMT on September 02, 2009    
oh boy that is scary. My husband thinks I am nuts but I have tons of hurricane plans should something come our way because I do not want my daughter going through anything more then a cat 1.
Member Since: July 6, 2006 Posts: 0 Comments: 70
1104. DaytonaBeachWatcher 6:37 PM GMT on September 02, 2009    
Quoting hurricane23:
12z ECMWF,CMC,UKMET dissipate erika in the not too distant future.


really

Link
Member Since: June 29, 2007 Posts: 0 Comments: 1125
1106. TreasureCoastFl 6:38 PM GMT on September 02, 2009    
Quoting IKE:


Okay...I see the recon fix. NHC was wrong on their coordinates listed.

so it's more northeast than they had it?
Member Since: August 18, 2008 Posts: 0 Comments: 444
1107. JupiterFL 6:38 PM GMT on September 02, 2009    
Quoting SQUAWK:

Pay the $10 and become a member and you will never have the problem again. Plus you get a lot more features that the site offers.


It is so worth it. The site works much better.
Member Since: August 10, 2005 Posts: 0 Comments: 2146
1108. GeauxGirl 6:38 PM GMT on September 02, 2009    
Quoting louisianaboy444:
Hey all i am reporting from the Weather Research Lab at ULM and we are analyzing Erika...I agree that she appears to be weakening but i think better conditions will ensue once she gets closer to the Bahamas...i also think the 12Z GFDL has the best track for this system as of now...


Would that be ULM, as in the University of Louisiana Monroe? Alias, the Tide Rollers?
;)

Member Since: September 2, 2008 Posts: 0 Comments: 103
1109. Floodman 6:38 PM GMT on September 02, 2009    
Quoting dwpearson:
Norman Anitvirus.


I love it...medieval French software...not very effective on the modern, non-peasant CPUs
Member Since: August 2, 2006 Posts: 10 Comments: 9919
1111. centex 6:39 PM GMT on September 02, 2009    
It is a virus JS/Exploit-Packed.c.gen low risk trojan type.
Member Since: August 10, 2007 Posts: 0 Comments: 2856
1112. BurnedAfterPosting 6:39 PM GMT on September 02, 2009    
Quoting DaytonaBeachWatcher:


really

Link


I dont see where the CMC or EURO dissipates Erika
1113. TreasureCoastFl 6:39 PM GMT on September 02, 2009    
Quoting hurricanehanna:
1094. Squak - nope, no ads.

Quote feature doesn't work either. I've run everything. It's only hitting from this site.

I'd reboot
Member Since: August 18, 2008 Posts: 0 Comments: 444
1114. FLWeatherFreak91 6:39 PM GMT on September 02, 2009    
Quoting Drakoen:
Well wow. It looks like it is going to hit PR haha. That is fairly guaranteed.
Member Since: December 1, 2006 Posts: 2 Comments: 3462
1115. jeffs713 6:39 PM GMT on September 02, 2009    
Quoting SQUAWK:

Pay the $10 and become a member and you will never have the problem again. Plus you get a lot more features that the site offers.

Truer words have not been spoken.

The $10 a YEAR is well worth the investment.
Member Since: August 3, 2008 Posts: 15 Comments: 5722
1116. bloodstar 6:41 PM GMT on September 02, 2009    
Quoting BurnedAfterPosting:
I am seeing PLENTY of TS force wind readings from recon


At this point there's no doubt that Erika is still a tropical storm. but it's struggling to bring all the pieces together. I do think that if Erika gets a 24 hour window with low shear, the storm will take off like a rocket. Fortunately Shear doesn't appear to be abating in the near term.

Though with the slow movement of the storm, I wonder if we're looking at a lurker of a storm that simply holds on. Something needs to move the storm along before it does get a chance to gather strength and become a real threat.

Member Since: August 12, 2009 Posts: 0 Comments: 5
1117. IKE 6:39 PM GMT on September 02, 2009    
This airport is 42 miles WSW of the recon center fix.

I'll be watching to see if their winds ever come up. If not, those winds from recon may not be reaching the ground.
Member Since: June 9, 2005 Posts: 23 Comments: 37047
1118. keys33070 6:40 PM GMT on September 02, 2009    
Quoting bocahurricane:
oh boy that is scary. My husband thinks I am nuts but I have tons of hurricane plans should something come our way because I do not want my daughter going through anything more then a cat 1.



Me as well!!! Nothing wrong with that. One can be under prepared, but never overly.
1119. SQUAWK 6:40 PM GMT on September 02, 2009    
Quoting Floodman:


I had to do it the other day...someone installed Norton on a McAfee box here...drop into safe mode as administrator and uninstall it...

Norton leaves all manner of junk behind when you do uninstall from control panel. You have to go to Norton's site and download their uninstall program and it will do a good job. Learned that the hard way. Same with McAfee. Neither one does a complete uninstall from control panel.
Member Since: December 9, 2008 Posts: 0 Comments: 2497
1121. jeffs713 6:40 PM GMT on September 02, 2009    
Quoting hurricanehanna:
1094. Squak - nope, no ads.

Quote feature doesn't work either. I've run everything. It's only hitting from this site.

Quoting likely isn't working because you have javascript turned off. You need to authorize scripts for both weatherunderground.com, and wxug.com.
Member Since: August 3, 2008 Posts: 15 Comments: 5722
1122. Drakoen 6:40 PM GMT on September 02, 2009    
NHC track likely to shift to the south and west a bit:

Member Since: October 28, 2006 Posts: 57 Comments: 29010
1123. DaytonaBeachWatcher 6:42 PM GMT on September 02, 2009    
Quoting BurnedAfterPosting:


I dont see where the CMC or EURO dissipates Erika

cmc does on the 12z run, but the ecmwf doesnt by what i was looking at. Not that any of that necessarily means anything. She will do what she wants regardless of what the models say
Member Since: June 29, 2007 Posts: 0 Comments: 1125
1124. JupiterFL 6:40 PM GMT on September 02, 2009    
Quoting DaytonaBeachWatcher:


really

Link


Is it me or did that run look off. She appears to jump all over the place.
Member Since: August 10, 2005 Posts: 0 Comments: 2146
1125. IKE 6:40 PM GMT on September 02, 2009    
Quoting TreasureCoastFl:

so it's more northeast than they had it?


By about 25 miles.
Member Since: June 9, 2005 Posts: 23 Comments: 37047
1126. alaina1085 6:41 PM GMT on September 02, 2009    
Quoting GeauxGirl:


Would that be ULM, as in the University of Louisiana Monroe? Alias, the Tide Rollers?
;)


Ya thats where he is.
Member Since: August 2, 2006 Posts: 0 Comments: 1234
1127. louisianaboy444 6:41 PM GMT on September 02, 2009    
Quoting GeauxGirl:


Would that be ULM, as in the University of Louisiana Monroe? Alias, the Tide Rollers?
;)



Tide Rollers? lol but yeah its ULM i work in the WRC
Member Since: August 29, 2006 Posts: 17 Comments: 1219
1128. obsessedwweather 6:42 PM GMT on September 02, 2009    
Erika isn't over....Look at the HUGE wave that will be coming off Africa!!!!!
1129. FloridaTigers 6:42 PM GMT on September 02, 2009    
Seems Erika is slightly intensifying.
Member Since: May 17, 2009 Posts: 0 Comments: 559
1130. TriniGirl26 6:42 PM GMT on September 02, 2009    
Quoting FLWeatherFreak91:
Well wow. It looks like it is going to hit PR haha. That is fairly guaranteed.


and u happy about that?
Member Since: August 18, 2009 Posts: 0 Comments: 201
1131. BurnedAfterPosting 6:42 PM GMT on September 02, 2009    
Quoting DaytonaBeachWatcher:

cmc does on the 12z run, but the ecmwf doesnt by what i was looking at. Not that any of that necessarily means anything. She will do what she wants regardless of what the models say


23 of course forgot to mention one very important thing. CMC kills Erika because it brings it over Hispanoila.

Guess that wasnt important
1132. Elena85Vet 6:42 PM GMT on September 02, 2009    
McAfee just blocked a Trojan from this site.
Member Since: August 18, 2008 Posts: 0 Comments: 619
1133. kmanhurricaneman 6:43 PM GMT on September 02, 2009    
62.0w 15.9n
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1135. DaytonaBeachWatcher 6:43 PM GMT on September 02, 2009    
Everythning about ERIKA from day 1 has been all over the place. I havent got a clue what she is gonna do or when. I am just watching and waiting. Even if she dissipates, i wont count her out, I will keep checking back for regeneration.. as i have seen it happen quite a few time before and when they are close to home you gotta keep your eyes open.
Member Since: June 29, 2007 Posts: 0 Comments: 1125
1136. BurnedAfterPosting 6:44 PM GMT on September 02, 2009    
Quoting kmanhurricaneman:
62.0w 15.9n


again that is NOT the true center

even recon verified that
1137. OSUWXGUY 6:44 PM GMT on September 02, 2009    
Here's what I don't get...

From the RGB image at 1745 or 4 minutes before the vortex fix was taken (1749), the center of the naked swirl is over one degree west of their coordinates and a little over a half of a degree south of their coordinates.

Their coordinates: 16.6333N 60.8333W

Center of Naked Swirl at 1745: 16.0N 62.0W


They mention a 10 mile tilt to the north which would explain the half degree south bias, but does NOT explain the west by over a degree bias...

What am I missing? Is there something wrong with the SSD projection?
RGB Loop
1138. FLWeatherFreak91 6:44 PM GMT on September 02, 2009    
Quoting TriniGirl26:


and u happy about that?
Indifferent. It isn't a threat to the island, and the island will help it not to be a threat to me.
Member Since: December 1, 2006 Posts: 2 Comments: 3462
1139. scott1968 6:44 PM GMT on September 02, 2009    
Quoting StormW:
TROPICAL STORM ERIKA SYNOPSIS SEPTEMBER 02, 2009 ISSUED 2:20 P.M. EDT


Good info thanks! If you do not mind me asking...where were you stationed towards the end of your enlistment? You look familiar.
1140. kmanhurricaneman 6:44 PM GMT on September 02, 2009    
center of other circulation moving wsw
Member Since: August 14, 2008 Posts: 0 Comments: 1002
1141. keys33070 6:45 PM GMT on September 02, 2009    
Quoting DaytonaBeachWatcher:
Everythning about ERIKA from day 1 has been all over the place. I havent got a clue what she is gonna do or when. I am just watching and waiting. Even if she dissipates, i wont count her out, I will keep checking back for regeneration.. as i have seen it happen quite a few time before and when they are close to home you gotta keep your eyes open.


She is like a crazy ex girlfriend
1142. bocawind 6:45 PM GMT on September 02, 2009    
Quoting bocahurricane:
oh boy that is scary. My husband thinks I am nuts but I have tons of hurricane plans should something come our way because I do not want my daughter going through anything more then a cat 1.


I decided to ignore categories. Anything that comes my way, I will shutter up. Wilma was supposed to be no big deal, and it did way more damage to my house than Francis or Jeanne combined.

Plus, cyclones can ramp up very quickly in the warm waters in front of us.
Member Since: September 1, 2009 Posts: 0 Comments: 1
1143. DaytonaBeachWatcher 6:45 PM GMT on September 02, 2009    
ok jp, please keep me outa your arguments with 23. I was just noting that the link i have didnt show what he was saying. Maybe mine is wrong.
Member Since: June 29, 2007 Posts: 0 Comments: 1125
1144. Orcasystems 6:45 PM GMT on September 02, 2009    
Ahhh crud... track and model shift... man the life rafts... the blog is going to go nuts with doom casters :(

Member Since: October 1, 2007 Posts: 77 Comments: 26077
1145. BurnedAfterPosting 6:45 PM GMT on September 02, 2009    
Quoting OSUWXGUY:
Here's what I don't get...

From the RGB image at 1745 or 4 minutes before the vortex fix was taken (1749), the center of the naked swirl is over one degree west of their coordinates and a little over a half of a degree south of their coordinates.

Their coordinates: 16.6333N 60.8333W

Center of Naked Swirl at 1745: 16.0N 62.0W


They mention a 10 mile tilt to the north which would explain the half degree south bias, but does NOT explain the west by over a degree bias...

What am I missing? Is there something wrong with the SSD projection?
RGB Loop


the naked swirl is NOT the true center

the NHC positions is the average between the two circulations, but to me it appears the one inside the convection is winning out.
1146. AllStar17 6:46 PM GMT on September 02, 2009    
I see nothing has changed this afternoon.

Erika's future remains EXTREMELY hard to forecast. Anywhere between the northern portions of Cuba to north of the Bahamas.....and anywhere between dissipated and Category 3 hurricane is possible.
Member Since: June 29, 2009 Posts: 13 Comments: 5135
1147. IKE 6:46 PM GMT on September 02, 2009    
What a reversal on the 12Z CMC. Here's the last frame before hitting DR/Haiti....at 36 hours....

Member Since: June 9, 2005 Posts: 23 Comments: 37047
1148. BurnedAfterPosting 6:46 PM GMT on September 02, 2009    
Quoting DaytonaBeachWatcher:
ok jp, please keep me outa your arguments with 23. I was just noting that the link i have didnt show what he was saying. Maybe mine is wrong.


no yours was right, I see it too
1149. mrpuertorico 6:46 PM GMT on September 02, 2009    
Quoting keys33070:



It all goes back to no one really knows what she will decide to, typical of a woman, but what was Andrews excuse -- didn't he play games for a while, then BAM suprise I'm here.


lol its like a blind date you don't know how its going to go until its done
Member Since: July 10, 2006 Posts: 0 Comments: 833
1150. JupiterFL 6:47 PM GMT on September 02, 2009    
Quoting apocalyps2:


a new blew up of convention.


You might want to remove that post. Pretty sure the government can arrest you for posting things like that.
Member Since: August 10, 2005 Posts: 0 Comments: 2146
1151. alaina1085 6:47 PM GMT on September 02, 2009    
Quoting Orcasystems:
Ahhh crud... track and model shift... man the life rafts... the blog is going to go nuts with doom casters :(



Kman was right about her wanting to enter the Carib.
Member Since: August 2, 2006 Posts: 0 Comments: 1234

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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.

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