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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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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I prefer "guesscaster"
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looks to be where the mid level low is

keep in mind more forecast models are saying Erika will survive today than last night
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Quoting StormW:


No hostiltiy Tim...but I mean come on...about 98% of the time on here, people scream fish right away with a new African system. I was just curious as to why.


You know i always got your back. Your correct. Sad part its often the people that are in here all the time.......Not to mention any names.....LOL
Member Since: September 2, 2007 Posts: 178 Comments: 20439
275. Relix
I am back from doing some quick preparations... AKA, Fuel, Propane Gas, candles, lighters and some food. I am pretty sure power will die down. Reporting from Levittown Puerto Rico, about a mile away from the beach and a few miles to the west of San Juan. Cloudy in many spots, some dark clouds to my left as well. A bit windy, light rains. Not much more right now.
Member Since: August 3, 2006 Posts: 0 Comments: 2701
12Z GFS 168 hours

Member Since: September 23, 2005 Posts: 14 Comments: 11053
Quoting mrnicktou:


even on this the storm looks to be going south of the models. The models havent been right since they predicted Erika to go hundreds of miles north of the Antilles. I just can't seem to grasp the fact that this storm will take a sudden turn north and either bring lots of rain to florida or just go up the east coast. It needs to do something quick because it would require a huge change in direction


I'm starting to think it's too far South of the influences they thought were going to turn it North. I have zero faith in the models or the official forecast track, if you go back and look none have been close yet and they continue to turn it North when Ericka continues to go a little South of due West. This is just one we have to monitor and watch closely.
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BAR, is that low exposed on visible satellite imagery or closer to the mid level low?
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Quoting StormW:


No hostiltiy Tim...but I mean come on...about 98% of the time on here, people scream fish right away with a new African system. I was just curious as to why.
they want to be the first so they can pat themselves on the back if they are right...they are also the first to change their tune when they see the actual track.
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Quoting jeffs713:

That reminds me... one tip for after a storm... don't try calling people. Text message. It uses up a lot less of the network, and your message is more likely to get through. It also allows real emergency calls to go through. (that is, unless you have a network like sprint's, which isn't at all resilient to losing a few towers)


Oh i wanted to throw my phone because I couldn't even get a text out. I didn't get many calls just texts and it would say stored 8:45 a.m. and received at 10:25 a.m. thats how bad it was and I couldn't get a message out but great advice there!
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Quoting StormW:


No hostiltiy Tim...but I mean come on...about 98% of the time on here, people scream fish right away with a new African system. I was just curious as to why.


Because they do not have anything better to say!
Member Since: August 15, 2009 Posts: 0 Comments: 90
Quoting StormW:


Not only that...but someone want to tell me..in general...what is the flow on the south side of the Atlantic ridge? East to what?

East to Florida.

Sorry, I had to. ;)
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new surface low possibly forming in the islands

turning really evident on radar and starting to on the visible

16N 62W
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Quoting StormW:
I'm just curious...why is it that everything that comes off Africa is "fish"? Ya ever think the pattern is telling us something that the waves coming off Africa keep getting closer and closer to the U.S. (i.e. Bill, Danny closer, now Erika).

Not only that...but someone want to tell me..in general...what is the flow on the south side of the Atlantic ridge? East to what?


Fish?
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I'm just getting an ill feeling Erika just hanging around for that dang trough to lift out and a big high to move in....Its kinda wierd. Most systems in that location usually don't stall or move so slow in that area the way Erika has done. She has really hardly moved much in the past few days because of weak steering.....That seldom happens in that location...
Member Since: September 2, 2007 Posts: 178 Comments: 20439
The Fred wave already appears to have two large banding features, one to the west and the other to the south. Amazing to watch such a beautiful wave begin to develop. I would be amazed to see how its convective cycles initate.
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Quoting jrb01:


Only takes a couple of nasty ones and you'll wish one NEVER hits near your home or your loved ones. I used to think hurricanes were cool. Then wilma came and destroyed my roof and smashed up one of our cars, and we lived for more than a week without power. I helped my parents dig out from Ivan after it dropped 100+ trees in their yard and pancaked 3 vehicles parked in the driveway. If I never see another hurricane firsthand, I'll be a happy man.


Thats why people move to California lol. Well my aunt needed help with Wilma and I wanted to go down there and help here. Theres just something about hurricanes/tornados that gets my adrenaline going ever since I was little. I hope people never get hurt by them I do but honestly these storms are amazing and I want to experience as many as I can
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serialteg, I am so glad you felt the need to hightlight those words. I, myself, look at all models and haven't show any real concern for this particular storm. What I was stating, is that on this blog, if someone doesn't agree with certain people on tracks, or if the do ask if a storm is coming their way, they are suddenly labeled a wishcaster. Most people here are not. I just wish (ok, this is wishcasting) that people weren't so quick to label others here.
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I'm just curious...why is it that everything that comes off Africa is "fish"? Ya ever think the pattern is telling us something that the waves coming off Africa keep getting closer and closer to the U.S. (i.e. Bill, Danny closer, now Erika).

Not only that...but someone want to tell me..in general...what is the flow on the south side of the Atlantic ridge? East to what?


Becareful StormW, people in here call that "Newcasting" or "Westcasting".. I get called that everytime I call for people in the Northeast to watch a storm. People in here need to mature up, man up, and just get over the fact that a Hurricane will hit the Northeast USA sometime over the next few years. Gotta go back to class, bbl
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I like the comments that people that live in Florida are floridacasters, and those that live on the GOMEX wish storms our way. Please! Pay my homeowner's insurance premium for a couple of months and then tell me I'm a wish caster! My insurance alone is probably more than your RENT! LOL
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Quoting hurricane23:


I cant help but think with the overall pattern in place this thing should also fish but who knows.


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.
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256. jrb01
Quoting mrnicktou:
Quoting jeffs713:
Honestly I live in houston and for some reason when Ike was still out in the ATL i wanted it to come here. Never experienced a hurricane before ....


Only takes a couple of nasty ones and you'll wish one NEVER hits near your home or your loved ones. I used to think hurricanes were cool. Then wilma came and destroyed my roof and smashed up one of our cars, and we lived for more than a week without power. I helped my parents dig out from Ivan after it dropped 100+ trees in their yard and pancaked 3 vehicles parked in the driveway. If I never see another hurricane firsthand, I'll be a happy man.
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Quoting mrnicktou:


even on this the storm looks to be going south of the models. The models havent been right since they predicted Erika to go hundreds of miles north of the Antilles. I just can't seem to grasp the fact that this storm will take a sudden turn north and either bring lots of rain to florida or just go up the east coast. It needs to do something quick because it would require a huge change in direction


Coming out of deep lurk mode just long enough to say that I agree with you 100%. Models have been relentlessly predicting WNW and NW motion for Erika since she was named. She has just as relentlessly ignored the models and overall has tracked just south of west..
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Quoting StormW:
I'm just curious...why is it that everything that comes off Africa is "fish" Ya ever think the pattern is telling us something that the weaves coming off Africa keep getting closer and closer to the U.S. (i.e. Bill, Danny closer, now Erika).

Not only that...but someone want to tell me..in general...what is the flow on the south side of the Atlantic ridge? East to what?


Do i sence some hostility ......LOL....as my momma always told me CALM YOUR AS_ DOWN NOW!....LOL
Member Since: September 2, 2007 Posts: 178 Comments: 20439
234, the anticyclone you're looking for is in the upper levels of the atmosphere. won't be on any radar. may be visible on water vapor sattelite loops...look for clockwise flow.

Thanks. :)
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Quoting jeffs713:

Thank you.

The drive between Nederland and Winnie, and seeing all the dead trees inspired that blog posting. Now if I can just get to posting more frequently (I've posted 3-4 other blogs since then - one two days ago, but want to get onto a roughly weekly basis)


cool deal! I will have to stop in and check them out. :D

Also, in LaBelle, which is between nederland and winnie, the government is buying out the property since the land is so low. There is thousands of homes, a lot brand new, that are being bought and leveled. It is kind of sad to see all the new development being destroyed.
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Quoting mrnicktou:


Oh my uncle who we couldn't get ahold of since the eye of the storm or the fact that room temperature drinks are better (I think). Dude it was a bad storm we lost lots of trees around my house and around this whole area. Luckily we didn't have any directly come down on the house until after the storm ended and then one fell on the roof for some reason. I had to drive up to my work and do work there to before the electricity even came on and it was hot and nasty. But it makes you appreciate everything you have and even if you can't have it it shouldn't really make your life that miserable. Dont forget nobody in houston had any cell service or could talk to people. I had friends across the country asking me if i was alright but i couldn't get a message out to them

That reminds me... one tip for after a storm... don't try calling people. Text message. It uses up a lot less of the network, and your message is more likely to get through. It also allows real emergency calls to go through. (that is, unless you have a network like sprint's, which isn't at all resilient to losing a few towers)
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The reason it appears to me that Erika is not organizing is not the upper level shear, but the mid level shear. This is keeping the two center of circulations at both the mid and low levels from becoming vertically stacked on one another.
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Quoting IKE:


I agree. I've said they should "downgrade" it, not RIP it.
gotta admit, Fay had a mind of her own also. If I remember she seemed to defy all logic, reason and models. Jeanne (2004) also fit in as unusual but thats because of the interaction and weakening from Hispaniola (she had a well established structure to begin with so regeneration was not all that surprising, just the track).
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Wow that wave now emerging off of Africa's west coast is amazing to look at. Outflow looks substantial in all quadrants and definite low level low pressure. This wave if it can get some convection going watch out Cape Verde Islands. Amazing if that wave had the convection that Erika is producing. She is a fighter and until she is dissipated we have to watch her. Another area of interest I am looking at would be that area of thunderstorms by the southwestern Bahamas. Convection is increasing in growth with an upper level anticyclone aloft in the region. Wind shear is to the west though and so is possible land interaction with Florida and the trough is pointing NEward for this little area of convection. Remember that Hurricane Bill is still considered a Cape Verde Hurricane.
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Quoting BiloxiIsle:
I hate the term "wishcasting". Anytime someone shows concern about a tropical system possibly coming their way, they are labeled wishcasting. If a particular model starts showing trends towards the GOM and I state my concerns, this does not mean I am "wishcasting". A true wishcaster is someone who says "I really hope this system gets in the Gulf". Yes, there are a few children here who does make such crazy statements, but most of us do not.

AMEN !!!!!
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Quoting mrnicktou:


Dude it was a bad storm we lost lots of trees


heh
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Quoting Noshutters:
Much needed heavy rains ? Ahem, I don't think so. I live on Dominica, the ground was already saturated and we have had landslides this morning. Sorry to say this but there has been too much (poor) guesswork and not enough fact on 94/Erika.


I believe storms like these are notoriously hard to predict. They do their best, they really do, the mets... but science is playing catch-up with nature, remember that.
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241. IKE
Quoting usa777:
I havn't seen a storm give so many people issues like this thing in a long time. Even the professionals are scratching thier heads. I wouldn't count this thing out yet!


I agree. I've said they should "downgrade" it, not RIP it.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting jeffs713:
212. I'm not quite sure how to respond to that. You obviously didn't lose any possessions, nor did you get to experience the excitement of feeling your entire apartment building move with each wind gust. And you apparently are completely ok working in an office with 400 other people with 80 computers between you. Or taking cold showers every day until your power came back on. Or when you want a drink, you have a choice between room temp water, room temp gatorade, or room temp (and flat) soda. Oh, lets not forget having intermittent contact with the outside world, and being concerned for your family who lives an hour away.

Yeah, thats all terribly exciting.


Oh my uncle who we couldn't get ahold of since the eye of the storm or the fact that room temperature drinks are better (I think). Dude it was a bad storm we lost lots of trees around my house and around this whole area. Luckily we didn't have any directly come down on the house until after the storm ended and then one fell on the roof for some reason. I had to drive up to my work and do work there to before the electricity even came on and it was hot and nasty. But it makes you appreciate everything you have and even if you can't have it it shouldn't really make your life that miserable. Dont forget nobody in houston had any cell service or could talk to people. I had friends across the country asking me if i was alright but i couldn't get a message out to them
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234, the anticyclone you're looking for is in the upper levels of the atmosphere. won't be on any radar. may be visible on water vapor sattelite loops...look for clockwise flow.
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Quoting SomeRandomTexan:
Jeffs, read the blog, great job!

Thank you.

The drive between Nederland and Winnie, and seeing all the dead trees inspired that blog posting. Now if I can just get to posting more frequently (I've posted 3-4 other blogs since then - one two days ago, but want to get onto a roughly weekly basis)
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Quoting hurricane23:


I cant help but think with the overall pattern in place this thing should also fish but who knows.
not sure about that, coming off mighty low...may be able to sneak by depending on its (if) organization/strength.
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Quoting Noshutters:
Much needed heavy rains ? Ahem, I don't think so. I live on Dominica, the ground was already saturated and we have had landslides this morning. Sorry to say this but there has been too much (poor) guesswork and not enough fact on 94/Erika.


Sorry to hear that but glad you posted that information. Important to bring some perspective to the damage these systems can bring regardless of their official designation. Do you know if anyone was hurt?
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Interesting...12z CMC puts remnants of Erika in the GOM. Worth considering, although unlikely.
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Quoting reedzone:
The anticyclonic flow is still there and still looks to be splitting up the high wind shear. This might be some hope for Erika if trend continues



What's the best radar to observe the anticyclonic flow? And what would I be looking for?

Pardon my ignorance and thanks in advance for the info.
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We will have plenty of time to watch it, too early to make calls yet.
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Quoting BiloxiIsle:
If a particular model starts showing trends


I highlighted the 2 key words in your statement.

You want to know how many times the models have brought over / off Puerto Rico this particular Erika storm? And we're not 200 miles from it... just imagine something as far as the Gulf, or even Florida.

Spend years tracking and looking at models and you'll be a believer too :D
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212. I'm not quite sure how to respond to that. You obviously didn't lose any possessions, nor did you get to experience the excitement of feeling your entire apartment building move with each wind gust. And you apparently are completely ok working in an office with 400 other people with 80 computers between you. Or taking cold showers every day until your power came back on. Or when you want a drink, you have a choice between room temp water, room temp gatorade, or room temp (and flat) soda. Oh, lets not forget having intermittent contact with the outside world, and being concerned for your family who lives an hour away.

Yeah, thats all terribly exciting.
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Quoting StormW:
Our friend out east...starting to fire a small area of convection

another Krispy Kreme glazed...the year of the doughnut.
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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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