Erika dumping heavy rain on the Lesser Antilles

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

Share this Blog
1
+

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.

McAfee virus alert messages
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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 230 - 180

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21Blog Index

Quoting StormW:
Our friend out east...starting to fire a small area of convection

another Krispy Kreme glazed...the year of the doughnut.
Member Since: Posts: Comments:
Quoting P451:
~10HR WV Loop



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
Member Since: July 28, 2009 Posts: 1 Comments: 64
Quoting rwdobson:


Well, you used Katrina as an example...I'd call that a "well defined storm".


In well-defined storms, you are correct. But you just said hurricanes. :)
Member Since: Posts: Comments:
Quoting StormW:
Our friend out east...starting to fire a small area of convection



I cant help but think with the overall pattern in place this thing should also fish but who knows.
Member Since: May 14, 2006 Posts: 8 Comments: 13699
Jeffs, read the blog, great job!
Member Since: August 30, 2007 Posts: 0 Comments: 1837
Quoting jeffs713:

Let me rephrase that:

It doesn't make sense to issue a TS warning for something that just weakened to a TD.


Why wouldn't it make sense if there's even a slight possibility the system could have a flare up that induces tropical storm-force conditions at the surface? You have to look at the possibilities, not what is more likely. Image a 70mph storm made landfall in Miami. No hurricane warnings issued. A weather station there reports sustained winds of 75mph.All of a sudden, it's a hurricane? But, people yell - and they will - about insufficient warnings. A lot of times meteorological forecasting is not about being right, it's about being overdramatic to save your a**. Why do you think all the news stations make such a big deal about minor weather events such as a little street flooding? It's everywhere. Especially if theire on-camera guy just said the area would get hammered - and 1-inch of rain fell. But, find a flooded street and there will be news cameras there. There's more business in weather than you may realize. And it's BIG BUSINESS (look at this site)
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
I don't see any signs of the anticyclone dissipating. Outflow is still tremendous within the convection. Also upper level divergence is still going strong.
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
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!
Member Since: Posts: Comments:
"heh... well, its one thing to OWN something and another to OWE

most are homeOWERS hehe"

LOL Very tue! I find it hard to believe that anyone that has already incurred the increase in HO Insurance premiums in this are would EVER wish a storm anywhere within a thousand miles of here.
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

Member Since: Posts: Comments:
Quoting timtrice:


That also is incorrect. In well defined storms, yes.


Well, you used Katrina as an example...I'd call that a "well defined storm".
Member Since: Posts: Comments:
People keep in mind that the CONE includes some west motion as well
Member Since: Posts: Comments:
Erika is lacking any vertical stacking of LLC and MLC. MLC I believe is seen as the big spin of echoes on the radar in the Lesser Antilles and the visible shows the LLC if becoming better organized is still exposed on the western side of the convection. It is still very disorganized.
Member Since: Posts: Comments:
Quoting hurricanejunky:

I don't know that it's so much Floridacasting as it is the fact that this storm has been one of the crazy ones.



There are some people here that start screaming Florida when a wave exits the African coast. Probly tracking them all the way from India...

Those are my beloved Floridacasters.
Member Since: Posts: Comments:
Quoting jeffs713:
Also, as further to my earlier post, #91, I should mention that I find it terribly amusing to see all of these wishcasters freak out when a storm actually does take a track towards them. I saw it with Hurricane Ike here locally. Lots of people were talking (when Ike was still in the ATL, before hitting Cuba), that it would be cool to get a good hurricane here, and "break up the monotony". Once Ike was actually taking a track right towards us, and was HUGE... they were freaking out and completely getting all kinds of stressed / worried. I'm pretty sure that when a storm hits the Florida-casters, the same thing will happen to them.

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 was in an airplane taking off through Tropical storm Allison but thats pretty much it. And even as the days closed in on the storm as it got here me and my buddies went over to buffalo wild wings to eat and people were freaking out in there and all the tv's had it on. the only thing that mad me angry was the day after the storm passed was Ohio State usc game and i couldn't watch it. The whole 16 days w/o power in houston didn't bother me yea it got hot but still didn't rely on power just did other things it was actually kinda fun
Member Since: July 28, 2009 Posts: 1 Comments: 64
12Z GFS now on more of a GFDL/HWRF track, interesting to see if it continues.


Member Since: Posts: Comments:
Quoting masonsnana:

I see this!! LOL She is a very confusing storm at best! She is going to drive us crazy!

yes in deed she is
Member Since: Posts: Comments:
Quoting reedzone:
With the way things are going, and now that the anticyclone is dissipated, Erika should be downgraded by 5 or 8 p.m. Maybe some restrengthening after it crosses 20-30 knots of wind shear.


New 12z NAM/GFS give some hope to ana 2.
Member Since: May 14, 2006 Posts: 8 Comments: 13699
Member Since: Posts: Comments:
Quoting iluvjess:
I can assure you that anyone that is a homeOWNER and pays for insurance along the GOMEX or East Coast of FL is not a wishcaster!


heh... well, its one thing to OWN something and another to OWE

most are homeOWERS hehe
Member Since: Posts: Comments:
Quoting rwdobson:


the difference is, in Hurricanes, the winds are in all directions from the center, usually in a somewhat symetrical shape. Not so with storms like Erika and Danny.


That also is incorrect. In well defined storms, yes. But there are plenty of hurricanes that have only had hurricane force winds in one or two quadrants of the storm. The NHC downplays one observation of hurricane-force winds if that is in a thunderstorm (which is BS to me but, oh well). Howver, multiple observations of hurricane force winds, even away from the center, and the system will be upgraded. 20+ years of tracking and I've seen it at least once a year
Member Since: Posts: Comments:
Quoting EarthMuffin:
I dont care for models. They are vague at best, and frequently wrong. Look at last night's models, for instance. Could anyone really draw any conclusion from that mess? One had Erika heading WSW, another W, another WNW, yet another NW, and another nearly due N. A better "model" to use is history. What has happened to the previous 4 named storms this year, and why? This is an El Nino year, which also must be taken into consideration before referencing storms from last year or the year before that appeared to be on similar paths. Of course Erika can still end up in Florida or the GOM, but more than likely, it WONT.

I think I'll go back to lurking and amuse myself with the never-ending Floridacasting. After all, I lack a PhD so I cannot possibly be right, and besides, every storm must hit Florida. (*rolls eyes*)

I don't know that it's so much Floridacasting as it is the fact that this storm has been one of the crazy ones. When they act like this one all bets are off, models have a hard time latching on and at that point I think some good old fashioned human forecasting is required. Your guess is as good as any at this point...

Member Since: Posts: Comments:
Erica's outflow really expanded in the last few frames. And I see no movement N, just W.

IMHO, FWIW, IYDM...
Member Since: Posts: Comments:
plots for Jimena look like a meteor crashed into the Baja peninsula! LOL
Member Since: Posts: Comments:
With the way things are going, and now that the anticyclone is dissipated, Erika should be downgraded by 5 or 8 p.m. Maybe some restrengthening after it crosses 20-30 knots of wind shear.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting timtrice:


That's highly incorrect and it's done all of the time. Had Erika started off classified as a depression warnings would have been issued right away. That's like saying hurricane warnings won't be issued for a tropical storm. Completely inaccurate

Let me rephrase that:

It doesn't make sense to issue a TS warning for something that just weakened to a TD.
Member Since: Posts: Comments:
Quoting HIEXPRESS:
http://www.iwindsurf.com/windandwhere.iws?regionID=132&regionProductID=3&timeoffset=1


If it brushes Puerto Rico north, no biggie. Even if the LLC comes in, no biggie. The thing is the East side - if it rounds to our South then we're gonna see something
Member Since: Posts: Comments:
Quoting tropics21:
Doubt that the florida wishcasters live in Florida. those of Us in Florida do not wish any storms on Us We've has enough of them

Charlie survivor here, not wishing a storm on Florida or anywhere else. We watch closely knowing Florida's history and storms unpredictable. IE: Charley!!
Member Since: Posts: Comments:
Quoting jeffs713:
Since Hurricane Ike is getting some mention today (with Erika having organization issues), I figured I should post a link to one of my older blogs that has some info about the legacy that Hurricane Ike left behind. I actually did some research on this one, which is why I'm posting it here.

Link to an old blog from jeffs713


My pleasure. :)


as did I...

http://www.personalhurricanecenter.com/atlantic/atl-2008/9-hurricane-ike/blog/

Member Since: Posts: Comments:
Quoting timtrice:


In that case Ike and Katrina wouldn't have been hurricanes. Nor would Charley, Bret, or damn near every other storm. You are aware in most cases a hurricanes strongest winds are confined to a very tight radius of the eye? beyond 50-miles in most storms yo barely see storng troical storm force winds.


the difference is, in Hurricanes, the winds are in all directions from the center, usually in a somewhat symetrical shape. Not so with storms like Erika and Danny.
Member Since: Posts: Comments:
looks like that satellite image is not updating...sorry
Member Since: Posts: Comments:
Quoting jeffs713:

You can't issue a TS warning for a TD.


That's highly incorrect and it's done all of the time. Had Erika started off classified as a depression warnings would have been issued right away. That's like saying hurricane warnings won't be issued for a tropical storm. Completely inaccurate
Member Since: Posts: Comments:
I can assure you that anyone that is a homeOWNER and pays for insurance along the GOMEX or East Coast of FL is not a wishcaster!
191. IKE
Quoting serialteg:


Hey Ike, sorry about the LLC's earlier today. I totally missed the time on them. Winds are starting to pick up from the SSE on Guadeloupe, though.


No big deal.

Yeah...I see the gust to 31 mph. System is 150 miles WNW of Guadeloupe. They have higher winds now vs. when it was right over them(winds were 10-15 mph then). That sounds subtropical or extratropical.

If Erika was truly a tropical storm, it wouldn't be so heavily influenced by DMAX and DMIN everyday.

Just my unprofessional opinions.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Member Since: Posts: Comments:
Yet to me there should be a "percentage of storm" requirement to be met when classifying an entire entity as a 45mph TS.


In that case Ike and Katrina wouldn't have been hurricanes. Nor would Charley, Bret, or damn near every other storm. You are aware in most cases a hurricanes strongest winds are confined to a very tight radius of the eye? beyond 50-miles in most storms yo barely see storng troical storm force winds.
Member Since: Posts: Comments:
Quoting jeffs713:
Also, as further to my earlier post, #91, I should mention that I find it terribly amusing to see all of these wishcasters freak out when a storm actually does take a track towards them. I saw it with Hurricane Ike here locally. Lots of people were talking (when Ike was still in the ATL, before hitting Cuba), that it would be cool to get a good hurricane here, and "break up the monotony". Once Ike was actually taking a track right towards us, and was HUGE... they were freaking out and completely getting all kinds of stressed / worried. I'm pretty sure that when a storm hits the Florida-casters, the same thing will happen to them.
Doubt that the florida wishcasters live in Florida. those of Us in Florida do not wish any storms on Us We've has enough of them
Member Since: Posts: Comments:
Since Hurricane Ike is getting some mention today (with Erika having organization issues), I figured I should post a link to one of my older blogs that has some info about the legacy that Hurricane Ike left behind. I actually did some research on this one, which is why I'm posting it here.

Link to an old blog from jeffs713

Quoting AllBoardedUp:
Out of here, got to go the chiropractor. Nice talking with you Jeffs and Random

My pleasure. :)
Member Since: Posts: Comments:
Quoting sarahjola:
masonsnana-
glad to see i'm not crazy. lol! we have a few who agree and see the same thing.

I see this!! LOL She is a very confusing storm at best! She is going to drive us crazy!
Member Since: Posts: Comments:
Quoting jeffs713:

You can't issue a TS warning for a TD. Keep in mind one of the points for a TCFA is whether it is in within xxx miles of a DoD (Department of Defense) resource. There are certain actions governmental agencies can't do to prepare for a tropical cyclone unless a TS warning/watch is put into place. Also, with how unpredictable Erika has been, who is to say it couldn't find some way to suddenly organize into a solid TS?


True. We were discussing this before, one point to err towards the side of caution. Also this, brings some politics vis a vis science. Even so, there are west winds near the LLC's, and there are quite a few 50mph surface winds measured on the east...
Member Since: Posts: Comments:
Quoting jeffs713:

You can't issue a TS warning for a TD. Keep in mind one of the points for a TCFA is whether it is in within xxx miles of a DoD (Department of Defense) resource. There are certain actions governmental agencies can't do to prepare for a tropical cyclone unless a TS warning/watch is put into place. Also, with how unpredictable Erika has been, who is to say it couldn't find some way to suddenly organize into a solid TS?


You can issue a TS warning for a TD if there is a reasonable expectation that the storm will intensify into a TS within a short space of time.

TD4 of 2009 being the case in point:

ZCZC MIATCPAT4 ALL
TTAA00 KNHC DDHHMM
BULLETIN
TROPICAL DEPRESSION FOUR ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009

...TROPICAL STORM WARNING ISSUED FOR NEW DEPRESSION IN THE EASTERN
GULF OF MEXICO...

AT 5 AM EDT...0900 UTC...A TROPICAL STORM WARNING HAS BEEN ISSUED
FROM THE ALABAMA/FLORIDA BORDER EASTWARD TO THE SUWANNEE RIVER
FLORIDA. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM
CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24
HOURS.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
181. ch2os
Being a Floridian myself, I don't wishcast or Floridacast any storm. (Never rolling eyes, mother taught me well.) Florida sticks out like a sore thumb and Mother Nature is bound to toss a storm in its direction sooner or later. History proves that. Personally I'd enjoy them all missing the state. If the professionals are having a difficult time with understanding Erika thus far then certainly those of us without a degree are going to fair no better. Educated guesses or professional opiinions at best, and they are all thankfully welcomed. There are some posters here who strive for the safety and education for the public in preparing for and understanding severe topical weather. I appreciate them all. I believe most of us here are adults and generally behave as such.
I've said more now than I have in over five years I've been coming to this site so I will retreat back to my corner and return the board back to the more educated souls. Thank you.
Member Since: Posts: Comments:
Quoting AllBoardedUp:
The eye in Ike came right over my house in Hitchcock, across the bay from Galveston (wasn't here, vacated to the Hill Country). It's amazing the surge was that high over in the Golden Triangle. Bridge City has to be 70 to 90 miles from Galveston.


Glad to hear you took the warning and got out of town. How did your house make out?

Golden triangle has a bad setup since it is like a funnel to the gulf and the water really stacks up... My worst nightmare is to have a strong storm hit at High Island.
Member Since: August 30, 2007 Posts: 0 Comments: 1837

Viewing: 230 - 180

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.