Erika dumping heavy rain on the Lesser Antilles

By: Dr. Jeff Masters , 2:12 PM GMT on September 03, 2009

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Tropical Storm Erika is hanging together despite strong wind shear, and is bringing high winds and much-needed heavy rain to the Lesser Antilles Islands. Winds on the south shore of Dominica Island were sustained at 37 mph this morning, and 8.03" of rain have been measured at the airport over the past two days. Winds and rain at nearby islands have been less, according to our wundermap for the region. The Hurricane Hunters are in the storm now, and have generally encountered top winds of 40 - 45 mph at the surface. They did find one spot of 50 - 65 mph winds, but that was likely due to outflow from a strong thunderstorm, and is not representative of Erika's wind field.


Figure 1. Radar image of Tropical Storm Erika at 9:15am EDT 9/3/09. Image credit: Meteo France.

Erika has improved in organization a bit since last night, but remains weak and disorganized, thanks to about 20 knots of shear at the 200 mb level, as seen on last night's Guadeloupe upper air sounding. Radar animations out of Martinique show plenty of heavy rain moving through the Lesser Antilles, but little organization of the echoes. Satellite imagery shows no low-level spiral bands and little upper-level outflow. Long range radar out of Puerto Rico is beginning to show rain echoes from Erika approaching the island.

The forecast for Erika
The computer models have come into better agreement about the track of Erika, taking the storm west-northwest over Puerto Rico and the Dominican Republic. This track will take Erika into a band of significantly higher wind shear of 25 - 35 knots, Friday through Saturday. Considering that Erika is barely maintaining itself as a tropical storm with 20 knots of shear, the combined effects of the higher shear and the encounter with the high mountains of Hispaniola and Puerto Rico should be enough to cause Erika to dissipate by Sunday. Erika's remains will still be capable of dumping very heavy rains of 3 - 5 inches over the Dominican Republic and 1 - 3 inches over Haiti and the Southeast Bahamas, due to the slow motion of the storm. By Monday, when the remains of Erika should be over the Bahamas, the storm will have penetrated through the band of high wind shear over the Greater Antilles, and shear may fall low enough for redevelopment of the storm. This is a scenario offered by the NOGAPS model, which then takes Erika northward towards North Carolina. The other models predict quite a bit more shear in the region than the NOGAPS, and any redevelopment of Erika early next week remains an iffy proposition. The GFDL and HWRF models continue to insist that Erika will brush off the high shear this weekend, avoid Hispaniola, and intensify into a Category 2 hurricane five days from now. These models have not been giving enough emphasis to how the current shear is affecting Erika, and are being discounted at this time.

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A number of wunderground users with the McAfee virus protection software installed were alerted yesterday that a possible Trojan virus existed on our web pages. After an investigation of the issue, we have determined that this is a false alarm. It appears McAfee updated their virus files yesterday, and included in their list of suspected viruses JavaScript web pages that are compressed using the packer compression system used by wunderground. We've changed the compression technique used on our web pages, and hopefully this will eliminate the bogus McAfee alert messages.

Elsewhere in the Atlantic
A large, strong tropical wave with plenty of spin emerged from the coast of Africa this morning. The wave is not yet generating much in the way of heavy thunderstorms, but has the potential to gradually develop into a tropical depression by early next week. NHC is giving this wave a low (less than 30% chance) of developing into a tropical depression by Saturday. The GFS model has been consistently developing this wave in its runs over the past few days.

I'll have an update this afternoon.

Jeff Masters

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Quoting IKE:
12Z NOGAPS...


12Z CMC...
Why do you believe in these models?
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Quoting watchingnva:
looking at some of the loops and observations, this is what my amateur eyes are seeing...i think shes trying to have the coc in the islands work down to the surface...but if she doesn't continue to fire convection over and around it...she just might be gone by tomorrow...

img src="Image Hosted by ImageShack.us
" alt="" />

Great image, looks like you did a good analysis. I'm not sure about the spiral banding on the north side, though.
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Quoting watchingnva:
looking at some of the loops and observations, this is what my amateur eyes are seeing...i think shes trying to have the coc in the islands work down to the surface...but if she doesn't continue to fire convection over and around it...she just might be gone by tomorrow...

img src="Image Hosted by ImageShack.us
" alt="" />

Good observations, with Erika one never knows.
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375. IKE
Quoting Vortex95:


Is that Ericka?


Absolutely!
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting Grothar:
I know the center is supposed to be moving North on Erika, but all of the images show a SW movement to the convection. Instead of the NHC giving reports at 2:00, 5:00, 8:00, etc, do you think they should give them out like this; 12:01, 12:02, 12:03. I think we would be better informed. Strange little storm we have
LOL I agree with you with on S jog again. Models refuse to believe it. I dont understand.
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Lets her die in peace. Erika is almost dead and we are viewing some comments about strenghtening the storm???? I think it is just a matter of time (maybe hours) before NHC declares Erika officially dead. A simple review of satellite loops could prove this.
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Her convention does see, to be dying down! :) why was that so funny to me yesterday?
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Quoting Brillig:
Here's an update for Erika.


That's a brilliant product...it also shows what a real mess the circulation is, huh?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
370. BDAwx
Quoting LPStormspotter:


Where at?

Bermuda, i live just less that half a mile from the coast which is about as far inland as you can go here.
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369. IKE
12Z NOGAPS...


12Z CMC...
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Please someone go to the NHC site and look at the visible loop of Erika using Java then Flash.
Why are the trop points so much different between the two? Sure it is something simple but just curious. Sorry if already asked.
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Quoting Beachfoxx:
Hi all....

Watching Erika as she continues to swirl, looks like she's going to be around a few more days. : (


BFFFFFFFffffffffffffff hows it going Crip... long time no see :)
Member Since: October 1, 2007 Posts: 81 Comments: 26516
Ok enough lurking. Time to post something. Long time weather buff, but I am kind of a "child" here according to many of you (30th birthday coming up next week).

I just discovered this blog recently. The discussions here are addictive! I have no clue what Erika's gonna do, though I can't argue with any of StormW's logic. The NHC seems to keep forecasting a NW bias, and Erika's not listening.

The one and only thing I am wishcasting is that the weather associated with Erika moves away from Haiti. If she crawls across Hispaniola at the speed she's moving now. TC or not, it would be devastating for Haiti :(

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I know the center is supposed to be moving North on Erika, but all of the images show a SW movement to the convection. Instead of the NHC giving reports at 2:00, 5:00, 8:00, etc, do you think they should give them out like this; 12:01, 12:02, 12:03. I think we would be better informed. Strange little storm we have
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Quoting stormsurge39:
Thats a good visual, Im going to guess the S one. Thats what the models seem to be doing!!!
Guessing that is
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Quoting Beachfoxx:
Hi all....

Watching Erika as she continues to swirl, looks like she's going to be around a few more days. : (


Howdy, Foxx ; )
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting watchingnva:
looking at some of the loops and observations, this is what my amateur eyes are seeing...i think shes trying to have the coc in the islands work down to the surface...but if she doesn't continue to fire convection over and around it...she just might be gone by tomorrow...

img src="Image Hosted by ImageShack.us
" alt="" />
Thats a good visual, Im going to guess the S one. Thats what the models seem to be doing!!!
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Quoting BurnedAfterPosting:


Its forecast to miss Hispanoila completely now going north of it based on the NHC latest track


That's why I said a big IF. Not actually expecting it to happen but some here are suggesting it will.
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Quoting TexNowNM:


Jeffs, may I add this to your excellent response?

When a person has watched old people sobbing because their whole life has washed away; when the director a funeral home tells one, "Yes, we have been burying a lot more people than usual; It is so hard on the old folks;" when one helps working men and women clean up after losing everything they own; when one cooks a meal for people who did prepare for a hurricane with a hurricane closet full of food, but could not prepare to lose the closet with their house; when one helps calm the fears of children who can no longer sleep at night because that was when the water came; when one comforts those who have lost so much in three hurricanes in 36 months; then one may not find it so exciting. I won't even mention how many pets and wild animals died - maybe they mean nothing to some so they are irrelevant. My god, even a cow doesn't deserve to drowned, afraid and confused.

After reading a lot of the posts in the Houston Chronicle, it is obvious that many just don't get it. Personally, I prefer the kind of excitement that doesn't scar people, and they land on which they live, for life. Even little Humberto brought death to an old man in Bridge City, Texas. His family grieved. That is what hurricanes bring: misery, sadness, and death.

Excellent response. My heart still skips a beat when a strong gust of wind hits my apartment. I still pause whenever I smell any kind of sawdust and hear and leaf blower. Ike has left an impression on me that will never fade... just as it has left impressions, mental scars, and a few physical scars on millions of others in SE Texas.
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Quoting BDAwx:

I live on an island...


Where at?
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Quoting TheDawnAwakening:

Erika's picture.


Hey Dawn, 1. Right clip on the image. 2. Click on properties. 3. Highlight the link and Copy. 4. Go to blog page. 5 Click Image and you should get a dialogue box 6. Past link in the box and keep clicking until it appears in the comment box. You should have your picture.
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Quoting rwdobson:
IF and if it's a big if...IF it somehow survives and goes south of Hispanola...I think it would probably keep ambling west and be a threat only to Mexico and Central America.


Its forecast to miss Hispanoila completely now going north of it based on the NHC latest track
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Couple rebuttals: Hurricanes and tropical storms bring much needed rain to areas dependent on them, e.g. erica now. You cant just flat out say they bring misery sadness etc. It comes with the territory. Massive solar flares could kill us all but that doesnt mean get rid of the sun or criticize it for bringing death and destruction. On the other hand if you are a thrill junky keep it to yourself it's equally as ignorant to say woohoo hurricane! Imo....
As far as stormW's fish statement. Agree. But the fact remains that an east coast trof has been prevalent for the longest time. Couple that with donward motion and westerly shear from the uptick in tstorm activity in the Epac (El Nino) and you can pretty much say most anything that enters the Caribbean and/or Gomex is gunna get ripped to shreds. Of course that's not a guarantee and things could change but it's definitely the predominant feature.
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looking at some of the loops and observations, this is what my amateur eyes are seeing...i think shes trying to have the coc in the islands work down to the surface...but if she doesn't continue to fire convection over and around it...she just might be gone by tomorrow...

img src="Image Hosted by ImageShack.us
" alt="" />
Member Since: Posts: Comments:
352. BDAwx
Quoting LPStormspotter:


i guess you dont live on the coast

I live on an island...
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351. Relix
Seems Erika got tired of fighting nature =P
Member Since: August 3, 2006 Posts: 0 Comments: 2741
Quoting TexNowNM:


Jeffs, may I add this to your excellent response?

When a person has watched old people sobbing because their whole life has washed away; when the director a funeral home tells one, "Yes, we have been burying a lot more people than usual; It is so hard on the old folks;" when one helps working men and women clean up after losing everything they own; when one cooks a meal for people who did prepare for a hurricane with a hurricane closet full of food, but could not prepare to lose the closet with their house; when one helps calm the fears of children who can no longer sleep at night because that was when the water came; when one comforts those who have lost so much in three hurricanes in 36 months; then one may not find it so exciting. I won't even mention how many pets and wild animals died - maybe they mean nothing to some so they are irrelevant. My god, even a cow doesn't deserve to drowned, afraid and confused.

After reading a lot of the posts in the Houston Chronicle, it is obvious that many just don't get it. Personally, I prefer the kind of excitement that doesn't scar people, and they land on which they live, for life. Even little Humberto brought death to an old man in Bridge City, Texas. His family grieved. That is what hurricanes bring: misery, sadness, and death.



excellent post!
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IF and if it's a big if...IF it somehow survives and goes south of Hispanola...I think it would probably keep ambling west and be a threat only to Mexico and Central America.
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Quoting weathermanwannabe:


Good point; in the States as stange as it seem "Fall" is in the air and we may get an early Fall season....That may leave us with diminished CV action due to all the Trofs and perhaps a few tropical storms closer to home with the Gulf and Western Caribbean as the season closes out IMHO.


I predict a Plains/Midwest 'Indian Summer'. Mother Nature usually balances herself out.
Member Since: August 18, 2008 Posts: 0 Comments: 628
Quoting BDAwx:
hurricanes dont just bring misery, sadness, and death. they also bring rain to drought stricken areas thus averting widespread famine. It is a win some lose some situation.


i guess you dont live on the coast
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A naked spinner looks to have jumped out to the SSE of St. Croix coincident with the SW collapse of the northern blob. My guess is the northern half will attempt reform out there. Or could be curtains for the Northern half of this storm.
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341. IKE
12Z GFS @ 174 hours. WATCH OUT BERMUDA!!!!!!!

Member Since: June 9, 2005 Posts: 23 Comments: 37860
Are the models just shifting with every shift W or WNW? Is that how it usually works? I dont know anything about models.
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Quoting Vortex95:



No no no, Spiral banding you said it was begininng again? how long has it been since spiral banding was evident.


I've been out on a job site. First noticed it when I got back. Sorry I mis-understood :-)
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336. BDAwx
hurricanes dont just bring misery, sadness, and death. they also bring rain to drought stricken areas thus averting widespread famine. It is a win some lose some situation.
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Link
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Hi all....

Watching Erika as she continues to swirl, looks like she's going to be around a few more days. : (
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Here's an update for Erika. For an explanation, see http://www.pbase.com/victorengel/image/116846511

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331. IKE
Convection rapidly dying off again....For What It's Worth....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
The computer models have come into better agreement about the track of Erika, taking the storm west-northwest over Puerto Rico and the Dominican Republic.

Better agreement?? They are still out to lunch......http://my.sfwmd.gov/portal/page?_pageid=3194,21328260,3194_21169354:3194_21260388:3194_21 260861&_dad=portal&_schema=PORTAL
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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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