Erika steadily weakening

By: Dr. Jeff Masters , 7:43 PM GMT on September 03, 2009

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Tropical Storm Erika has weakened steadily this afternoon, and has not generated any sustained winds of tropical storm force (39 mph) at any weather stations in the Lesser Antilles Islands today, according to our wundermap for the region. Erika has dumped some heavy rain on the islands, with 8.03" of rain measured on Dominica over the past two days. The Hurricane Hunters are in the storm now, and have thus far found top winds of 36 mph at the surface and at their flight level of 1000 feet. Radar animations out of Martinique show that the areal coverage and intensity of rain echoes has diminished greatly since this morning, and IR satellite loops also show a major decrease in heavy thunderstorm activity. Visible satellite images (Figure 1) show that the low-level center has become exposed to view, and there is very little heavy thunderstorm activity near Erika's center. Erika is probably just a tropical depression now.


Figure 1. Visible satellite image of Erika showing the exposed swirl of its low-level center southeast of Puerto Rico.

The forecast for Erika
Erika is headed west, in defiance of most of the computer models that predicted a northwest or west-northwest track. Regardless, Erika's track will take the storm into a band of significantly higher wind shear of 25 - 35 knots, Friday through Saturday. Considering that Erika is steadily weakening and is barely alive now, the storm should dissipate by Saturday, and perhaps much sooner. Erika's remains will still be capable of dumping very heavy rains of 3 - 5 inches over the Dominican Republic, Puerto Rico, and the northern Lesser Antilles Islands, and 1 - 3 inches over Haiti and the Southeast Bahamas over the next few days. However, the recent decrease of Erika's heavy thunderstorms makes lower rainfall totals more probable. By Monday, when the remains of Erika should have penetrated through the band of high wind shear over the Greater Antilles, shear may fall low enough to allow redevelopment. This is a scenario offered by the NOGAPS and GFS models. The other models predict quite a bit more shear in the region, and I believe any redevelopment of Erika early next week is unlikely. The GFDL and HWRF models continue to insist that Erika will head northwest, brush off the high shear, and intensify into a Category 2 hurricane five days from now.

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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 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 continues to predict development of this wave into a tropical depression early next week.

I'll have an update Friday.

Jeff Masters

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1247. msphar
Hey Jo, I'll take your offer. Do you have a concept for how this sort of modification is being effected ?
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Oh and check this out guys, I am in the skimming mood today, and I dop want to show you this wind shear, but also this. Look at the 1900 Galveston Hurricane:
First the wind shear


And the 1900 hurricane, compare it with Camile Hurricane
http://www.wunderground.com/data/dhc_archive_charts/at_1900_charts/at1900.gif
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1245. msphar
Beats me F5, don't know those rules.
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Quoting F5Tornado:


Ill aim for the tanker in route for Tampa Bay!

By the way, why doesn't NOAA, if the same system regenerates, just name the storm again? Or even name it Version 2? I am serious, why don't they?


They do.
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Quoting msphar:
please don't, you might hit my boat.


Ill aim for the tanker in route for Tampa Bay!

By the way, why doesn't NOAA, if the same system regenerates, just name the storm again? Or even name it Version 2? I am serious, why don't they?
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Hi, all... forgive me, but I'm back with my nightly comments about how we're weather-modding the potential CONUS-bound tropical systems again. Please know I don't necessarily believe it, but there were bizarre things on satellite last night, in front of Erika, that astute members like Tampaspin couldn't explain, and everyone keeps saying how bizarre these storms are, that none of them can get their acts together except Bill.

Well, Bill got its act together way away from the US, as opposed to the others, and even Bill, just at the point where it moved more northwest, and all the models had it strengthening to a high Cat 3, had its eye collapse like a flan in the cupboard, never to restrengthen... just like Gustav last year.

And tonight, and thanks for the link, iceman, what is showing on the radar aiming directly into the current possible COC of Erika's "remnant" from about 50 degrees NE? It shows up suddenly, then slowly dissipates. It's not a radar spoke as it doesn't line up with the PR radar displayed.

Any opinions tonight? If nothing else, it's certainly an explanation for why the models and the NHC sound like they're out-and-out guessing half the time, lately.

It doesn't matter if none of you want to discuss the possibilites of this, but it is something to think about. Thanks...

Jo
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Quoting JLPR:


lol yeah
I should try that or maybe not
that could just anger it and cause it to regenerate xD


Ill do it Ill do it!
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1239. Patrap
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1236. centex
Lots of moister from pacific storm and front coming.. They have us at 40% on friday. Drought area and praying.
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1235. centex
Quoting centex:
looks like from radar and sat COC is SE of PR moving west.
on track for now, this is not the norm for NHC track. They show a sharp turn to N, still can't figure that with weak system. But they did show that 72, 48 and 24 hours ago.
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1234. Patrap


Central Atlantic WV Loop
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1233. Patrap
This Wide GOES Loop of the GOM will Show the Next 48-60 Hours real well.

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1232. Patrap
A Low will Slide down from The Mid Mississippi Vally down into the Western GOM off of Lake Charles ,Louisiana and, spin up In the Western GOM off of or Sw of Galveston.




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1231. centex
looks like from radar and sat COC is SE of PR moving west.
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1230. Patrap
NexSat Houston 5 Day Viz Loop
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1229. Patrap
NexSat Zoomed New Orleans 5 Day Vis Loop
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1228. JLPR
not bad for a system that is almost dead

now im off to bed
later
xD
Member Since: September 4, 2007 Posts: 36 Comments: 5223
1227. centex
Erika is a struggling system. It has shown resistance to dissipating. I would not be surprised if it re-generates in coming days.
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1226. msphar
nite TS
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Quoting centex:
I even questioned StormW while banned on this blog about expecting weak system to go N. He said it did not matter weakness would pull it north. I didn't buy it the talk about low level sterring low trop system to N.


I agree with you.....i think the wave will stay in the Caribbean and become a player later near the GOM! Hope I'm wrong......Good nite everyone!
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1224. centex
Here is my question to stormw, not pinging him I respect him more than any of you guys. Just showing this was NHC thinking also on 8/31.

Quoting centex:
Ok, but doesn't that assume we have a TD at minimum?


Not really...the flow is basically the same right now at the shallow and mid layer level.

He is saying no matter how weak it would pull N. This is the big problem with models, NHC and many on this blog.
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1223. msphar
Half an hour and we'll see the grand emergence.
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1220. msphar
I think you are developing an abnormal personal relationship with Erika or her ghost.
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1218. centex
I even questioned StormW while banned on this blog about expecting weak system to go N. He said it did not matter weakness would pull it north. I didn't buy it the talk about low level sterring low trop system to N.
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1217. msphar
Still does in her death throes.
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1216. msphar
It also had the problem of multiple COCs for a long time.
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1215. centex
Quoting TampaSpin:


That and a lack of steering! It still is on the SE side of the Bermuda High and still not moving much..I can't ever remember a storm have this much lack of steering in that location.
My issue is weak an expecting N. It did fluctuate but forecast N with storm showing no signs of consistent strength was wrong. Before nearing Caribbean it already had pattern of up and down.
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1213. msphar
Perhaps a butterfly will flap its wings in Hispaniola and the swirl will home in on it.
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1212. JLPR
Quoting msphar:
please don't, you might hit my boat.


sure don't worry =P
wont do it
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting centex:
I think all the track confusion was caused more by how weak system would interact with weakness and not whether it grew to TS status. I think we learned a weak system will track more west than models have been programmed to expect.


That and a lack of steering! It still is on the SE side of the Bermuda High and still not moving much..I can't ever remember a storm have this much lack of steering in that location.
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Funny how Most of the Major Models have it going North. If it does go North it will miss alot of the stronger Shear and might have a chance of getting stronger. But, at its current status i just don't see it going North as weak as it is.
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1207. msphar
please don't, you might hit my boat.
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1206. JLPR
Quoting msphar:
iceman - jlpr could throw a rock at the center and hit it.


lol yeah
I should try that or maybe not
that could just anger it and cause it to regenerate xD
Member Since: September 4, 2007 Posts: 36 Comments: 5223
1204. JLPR
here comes the rain =P
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1203. msphar
iceman - jlpr could throw a rock at the center and hit it.
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Guess we'll be talking about 95L in a couple of days
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1201. centex
I think all the track confusion was caused more by how weak system would interact with weakness and not whether it grew to TS status. I think we learned a weak system will track more west than models have been programmed to expect.
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1198. JLPR
looked better earlier
Member Since: September 4, 2007 Posts: 36 Comments: 5223
1197. msphar
iceman - those models will give you bad dreams be careful
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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.