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 watchingnva:



can i have a link to that, pretty please...:)

Go here: http://twister.sbs.ohio-state.edu/surface/
and pick caribbean.gif
Member Since: Posts: Comments:
Quoting palmasdelrio:
Is a flare-up of thunderstorms tonight out of the question? Yesterday Erika looked really bad but at night it picked up quite a bit.
what's the fujuwara effect?


It's where to lows are in close enough proximity to start orbiting one another...typically one becomes dominant or stronger and consumes the other, typically resulting in a much weaker low, despite the stronger ingesting the weaker
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting palmasdelrio:
Is a flare-up of thunderstorms tonight out of the question? Yesterday Erika looked really bad but at night it picked up quite a bit.
what's the fujuwara effect?


Took me 0.31 seconds (not counting typing time) to come up with 230,000 hits for Fujiwara effect. The top listing is for the Wikipedia entry, which is concise and provides a decent explanation.

If everyone would just do a quick search before asking ...
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Quoting btwntx08:

have u look at an rgb loop on the storm its rotation clearly its closed


i'm not downcasting, but just not enough information given yet..need more time convection to build around the COC
Member Since: August 18, 2009 Posts: 0 Comments: 157
Quoting Wariac:
this has been one fun storm to watch. specially to see people so lost because of her.


That has to be entertaining, lol.
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Quoting serialteg:


You don't mean the current conditions, right... like this

Thanks, but wanted to see them all together on one plot.
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HHs just found 30mph extrap surface winds. Not much, but a lot better than they were getting out west.
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NexSat African view of the Wave Train
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Quoting atmoaggie:
Ah, found a good one.
Of course there is Unisys (had no buoy data).

And there is the one from OSU (shocked and dismayed that OSUWXGUY hasn't been blessing us with these):

(From 30 minutes ago)



can i have a link to that, pretty please...:)
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this has been one fun storm to watch. specially to see people so lost because of her.
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Quoting yonzabam:
As of 90 minutes ago, Erika still had 40 mph winds, according to the NHC, so not sure why she's being talked about in the past tense.



I got three words for Erika

Rest In Peace.....

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looks like recon might be heading east to check out the other suspect area now??

Link
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Ah, found a good one.
Of course there is Unisys (had no buoy data).

And there is the one from OSU (shocked and dismayed that OSUWXGUY hasn't been blessing us with these):

(From 30 minutes ago)
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Quoting WXHam:


Hopefully headed East?

lol,
Member Since: September 27, 2007 Posts: 1 Comments: 22270
Quoting TheCaneWhisperer:


Recon has a live feed in from the Blog.

2nd that west wind being interesting. I was about to commit to the 50% dissipation but, may have to hold that till morning.

That's correct. LRandyB is a featured blogger and flys those HH missions.
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Quoting ShesACaneiac:
I've been lurking for 3 days and I'm more confused now than I was 3 days ago.

I think everyone is confused with Erika (including Erika), so you are in good company.
Member Since: August 3, 2008 Posts: 16 Comments: 5891
Some of you on here make me laugh!

ERIKA is almost RIP, Western and Central ATL is quiet..
..only game of interest in south of the Cape Verde..potential FRED!!
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Quoting jeffs713:

And for those who don't quite get it yet, that was a lame attempt at a failed joke. (but it is still a nice swirl up in KY)
Does not sound right--Extremely dangerous hurricane Fred..its almost as bad sounding as hurricane Fifi.
Member Since: September 27, 2007 Posts: 1 Comments: 22270
Quoting serialteg:


?


Joking obviously
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Quoting jeffs713:

We will have to start over. Again. For the 5th time. (or something like that)


I'm going to have to bring a bottle of something to work tomorrow to deal with another day, lol.
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Hello all! Looks like there hasn't been much of a change in the last few hours. I noticed the models have it going more north now, but the storm is still taking a south route --- what is the deal with that?
954. WXHam
Quoting JLPR:
HHs are now heading west, probably to investigate the convection


Hopefully headed East?

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Quoting TheCaneWhisperer:


Recon has a live feed in from the Blog.


?
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I've been lurking for 3 days and I'm more confused now than I was 3 days ago.
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Quoting StormW:


Possibly 48 hours. Basically. The only reason I mention the TUTT axis is, and an axis is drawn on a map where the wind shift takes place (simple terms). This shift can be as little as 20 degrees in direction. Given the change in direction, this would be considered directional shear. Through the years, I've never really seen anything develop while in a TUTT axis.


Thanks for the answer StormW!!
Member Since: August 30, 2007 Posts: 0 Comments: 1857
As of 90 minutes ago, Erika still had 40 mph winds, according to the NHC, so not sure why she's being talked about in the past tense.
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948. JLPR
HHs are now heading west, probably to investigate the convection
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Quoting atmoaggie:
Anyone got a good source that plots wind barbs for every NDBC asset and every airport in the eastern Caribbean?
Cannot seem to find that among Wyoming, COD, rap.ucar, any of our other surface ob sources.
And no, coolwx.com not updating.


You don't mean the current conditions, right... like this
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Quoting serialteg:


It's heading towards the convection in the Leewards.


Recon has a live feed in from the Blog.

2nd that west wind being interesting. I was about to commit to the 50% dissipation but, may have to hold that till morning.
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Quoting AllStar17:
Thoughts on what will happen if Erika relocates back near Guadeloupe/Martinique?

Back in a few.

We will have to start over. Again. For the 5th time. (or something like that)
Member Since: August 3, 2008 Posts: 16 Comments: 5891
Quoting OSUWXGUY:


Maybe not in the surface observations, but this appears to be a quite vigorous mid-level circulation.

Look at the thunderstorms moving EAST in the south side of the storm...

RGB Loop


If that's the case wouldn't shear finish her off?
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Quoting btwntx08:
its a closed low


next open wave..
Member Since: August 18, 2009 Posts: 0 Comments: 157
Quoting cirrocumulus:
see rainfall in the radar but I don't see it in the conditions on Guadeloupe, Martinique, Antigua...

Granted there is still a heavy band out to sea at the east of Antigua, most likely the one with the winds...

But this is shaping to be another Ana - a non-event

Still, Puerto Rican mayor announcements on TV had them with their yellow rainproof hoodies on, when currently the conditions are ideal for a Margarita and good company under the sun @ the beach.

Good post.


LOL the Noticieros in Puerto Rico are masters of overreacting I know.... I can't wait to see them on the internet sweating their behinds off in those raincoats. holding on to a tree when the day out side is like going to the beach kinda day.... LOL....
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Quoting jeffs713:
nice little swirl over Kentucky. Could that be Fred? ;)


yup
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I still think she is ducking southward. Look out Jamaica!
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938. 789
Quoting jeffs713:
nice little swirl over Kentucky. Could that be Fred? ;)
roflmao
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937. JLPR
Quoting Drakoen:
winds shifting to the west in Dominica is interesting but there is not enough evidence to conclude the development of a closed low yet.


exactly
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Quoting Hurricane009:
Is he okay??
no.
Member Since: September 27, 2007 Posts: 1 Comments: 22270
the blog is going slower than usual... hmm... the children should be home soon, so it will likely speed up soon enough.
Member Since: August 3, 2008 Posts: 16 Comments: 5891
Quoting masonsnana:

Is there still a RECON out there??


It's heading towards the convection in the Leewards.
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Is a flare-up of thunderstorms tonight out of the question? Yesterday Erika looked really bad but at night it picked up quite a bit.
Quoting StormW:
First system I've seen doing the Fujiwara effect with itself! LOL!

what's the fujuwara effect?
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Quoting cirrocumulus:
Thanks for those images from time to time Patrap.


I 2nd that!
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Thoughts on what will happen if Erika relocates back near Guadeloupe/Martinique?

Back in a few.
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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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