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.

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 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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All named storms hit land (Danny as an Extratropical storm):

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I'm sorry if this has been asked before - Why are the GFDL and HWRF models acting so loony? Do they not deal well with weak/ill-defined storms?
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Nobody steered Jimena into the Baja, mother nature did its work so it is something beyond all of us. Those who love tropical cyclone sympathizes with Mexico but it was something beyond all off us no matter how much you downcast.
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Quoting MiamiHurricanes09:
Bill did not make landfall anywhere, it affected Bermuda but the eye did not cross over Bermuda. Ana did not affect anywhere as a TD.


Are you crazy? LOL

HURRICANE BILL INTERMEDIATE ADVISORY NUMBER 35A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
200 AM AST MON AUG 24 2009


...BILL MOVING ACROSS SOUTHEASTERN NEWFOUNDLAND...HURRICANE FORCE
WIND GUSTS REPORTED AT CAPE RACE...

BILL IS MOVING TOWARD THE EAST-NORTHEAST NEAR 40 MPH...65 KM/HR.
THIS GENERAL MOTION IS EXPECTED TO CONTINUE TONIGHT AND MONDAY. ON
THE FORECAST TRACK THE CENTER OF BILL WILL EXIT THE EAST COAST OF
SOUTHEASTERN NEWFOUNDLAND DURING THE NEXT COUPLE OF HOURS.


TROPICAL DEPRESSION ANA ADVISORY NUMBER 20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
1100 PM AST SUN AUG 16 2009

...ANA MOVING ACROSS THE LEEWARD ISLANDS...

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Quoting Weather456:
One of the causes why Erika convection increased and then decrease but has led it too weaken. Mid-level dry air was entrained into the system.


...shows a rather big difference between the 200 mb winds and the near surface winds with a 10-20 knot bias on the near surface easterlies explaining why the llc out raced the the convection.





Thank you, a picture is worth many words.

CRS
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Quoting Weather456:


did you notice the NHC issued watches and warnings for every storm this year. we were under ts watches for Ana. No fish storm in 2009.


true, even Danny had watches out
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Wrong Miami

Ana hit the islands and PR as a TD
Bill hit Nova Scotia as a Hurricane

sorry you are mistaken
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Ana is not Erika.
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Quoting BurnedAfterPosting:
there have been no fish storms this year


did you notice the NHC issued watches and warnings for every storm this year. we were under ts watches for Ana. No fish storm in 2009.
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nite flood
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Quoting BurnedAfterPosting:
Ana and Bill both impacted land

you have a case with Danny though I would say


Bill did not make landfall anywhere, it affected Bermuda but the eye did not cross over Bermuda. Ana did not affect anywhere as a TD.
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482. JLPR
Quoting serialteg:


Remember Ana



yes I remember Ana....and? =P
Member Since: September 4, 2007 Posts: 36 Comments: 5223
480. IKE
Quoting WindyCitizen:
Severe damage in central Baja being reported by the LATimes:


"Baja Bush Pilots has been monitoring the damage caused by hurricane/tropical storm Jimena in northern Baja California Sur. The situation, as reported earlier Thursday on Outposts, is bleak for many residents and disheartening for Baja aficionados who have grown fond of the region and its people.

Here's the midday update from the Bush Pilots, based not only on flyovers but reports from residents --before phone service went out, and in one instance a ham radio -- and members close to the situation:

-- Matancitas (Lopez Mateos): Almost 90% of structures are down or severely damaged. No water, power or telephone service.

-- Ciudad Constitucion: Most roofs are gone; severe damage to 70% of the buildings. No water, power or telephone service.

-- Loreto: No power or telephone service. Lines are down, trees are down. Buildings are damaged. The airport is closed.

-- Mulege: No water, power or telephone service. Water crested three feet above the bridge. Water was 2 feet deep in the fire station, which would mean that almost the entire town was flooded. There have been reports of loss of life. (Outposts has learned at least one man has died, according to authorities.)

-- Punta Chivato: One person indicates that the wind was over 100 mph before the indicator broke. Damage to almost everything. We should hear about the condition of the strip sometime today.

-- Santa Rosalia: Wall of water came down the canyon and through the town, washed cars, etc., into the ocean."


And with the damage these systems cause, I get griped at on here by a few for wanting tropical systems to dissipate.

Go figure.
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ships cant detect subtropical cyclones. Ships cant detect brief tropical storms either. ships detected long tracked systems thats why the tracking maps back before reliable methods looked weird.
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I'm out kiddos...play nice...
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Quoting Cotillion:
1845 did have poor technology, yes. However, there were these things called 'ships'. Most storms recorded were close to land, but not all.

It is feasible that a storm or two were missed. Same for 1914. But, for no storms recorded at all despite that shows a very low season regardless.

Plus, you said 'recorded'. And none were. ;)

(Yes, I'm being pedantic...)



: P
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476. JLPR
Quoting MiamiHurricanes09:
what about Bill, Ana, and Danny?


Bill hit Canada
Ana hit the Lesser Antilles and PR
Danny... well Danny was a fish =P it didn't hit land as a tropical system
Member Since: September 4, 2007 Posts: 36 Comments: 5223
ok Im out for a while, Daughter just got home from college for the weekend so were going to go to dinner. Be nice
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Quoting Cotillion:
1845 did have poor technology, yes. However, there were these things called 'ships'. Most storms recorded were close to land, but not all.

It is feasible that a storm or two were missed. Same for 1914. But, for no storms recorded at all despite that shows a very low season regardless.

Plus, you said 'recorded'. And none were. ;)

(Yes, I'm being pedantic...)
forget it...
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Ana and Bill both impacted land

you have a case with Danny though I would say


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The LBAR model has been the best one for Erika the last 5 days Its only been off by a 145 miles!! LBAR model has Erika going just over Hispanola and then just S of Cuba. Per Hurricane City
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Please remember that the GOM is very warm, SST 83-88F everywhere, aka "the Jacuzzi"!! This is an El Nino year, yes, BUT, those little troughs or fronts occassionally stall and morph into a tropical system, you're looking at a rapidly intensifying storm! Remember the weak tropical wave that became TS Claudette? The NHC said <30% chance of development, after moving into the GOM, the ULL moved, and 4 hrs later that innocent weak tropical wave had 50MPH winds! There will NOT always be unfavorable winds in the GOM this season. Remember also each year, regardless El Nino, La Nina or neutral conditions, there will be 2-4 CAT 3 storms pop up somewhere in the Atlantic basin. If one of those develops or moves into the GOM there are multiple millions in harms way! The GOM is relatively shallow, so if a storm sits in one spot, cold water upwelling can put a crimp in it! But there has been several storms, for example Hurricane Camille, in 1969, made landfall with 200MPH sustained winds, Gilbert in 1988 had winds over 175!
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Quoting BurnedAfterPosting:
there have been no fish storms this year
what about Bill, Ana, and Danny?
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469. Relix
If Erika regenerates and affects Puerto Rico I will gladly accept a 1 month ban! =P
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1845 did have poor technology, yes. However, there were these things called 'ships'. Most storms recorded were close to land, but not all.

It is feasible that a storm or two were missed. Same for 1914. But, for no storms recorded at all despite that shows a very low season regardless.

Plus, you said 'recorded'. And none were. ;)

(Yes, I'm being pedantic...)
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Quoting Cotillion:


1845. No storms recorded.


Since weather recording didn;t officially start until 1851, that answer may or may not be true but there are no records to prove it
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there have been no fish storms this year
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Quoting surfmom:
Defiant - Erika has been labeled defiant.....she's in in defiance of the computer models..... Fascinating.

I'm with Weather456 - until the last nail is hammered in her coffin... eyes wide open. The Hot Tub in the GOM is a magnet... hope she fizzles b/4 she dips her foot... That's where her defiance has me worried.

She has demonstrated a will to survive -- not over yet....



It's so far away, and there's so much shear, that with those 2 things I wouldn't even think about the GOM. And I believe conditions over there aren't that favorable anyway.

Heck, I'm less than 100 miles from it and already am going NEXT
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Also, while on the topic of ENSO episodes, I wanted to point out that the dynamical computer model with the best 6 month forecast for our current el nino episode is the ECMWF. It nailed our currect el nino, and its anomaly, correctly for the last 4 months........and its forecast was made in March! I'm not going to say that model is correct all of the time, but it has definitely had an edge over other models this year (albeit mainly on larger scale components).
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Quoting Cotillion:
No, I'm right.

I've yet to find any recordings of a storm in 1845.

But I did also add 1914 and 1983 for their respective records.



Due to the poor technology of 1845 they only knew that there was a system if it hit land. Look how many fishes we had this year. In 1845 they would of said we would of only had 2 or 3.
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One of the causes why Erika convection increased and then decrease but has led it too weaken. Mid-level dry air was entrained into the system. This is an upper air time cross section from Guadeloupe and the green represents moist air while the red represents dry air. Erika's convective bursts was likely due to warm air (from SSTs) below dry air which is an unstable situation but becuz this dry air was not in the upper levels but rather in the mid levels, evaporational cooling eventually cooled the mid-levels. The downdrafts may have hit the surface and aid in the further momentum of the LLC (below).



Vertical shear was 1 of the other causes. Below is the actual wind at Saint Maarten which shows a rather big difference between the 200 mb winds and the near surface winds with a 10-20 knot bias on the near surface easterlies explaining why the llc out raced the the convection.


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Quoting surfmom:
Defiant - Erika has been labeled defiant.....she's in in defiance of the computer models..... Fascinating.

I'm with Weather456 - until the last nail is hammered in her coffin... eyes wide open. the Hot Tub is the GOM is a magnet... hope she fizzles b/4 she dips her foot

She has demonstrated a will to survive -- not over yet....



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Erika is done so looking foward whats next. Fred.
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Quoting rareaire:


Well said however you and I are not the only ones on this blog. And we have the ignore feature to remove the wasted lines of those that do not contibute anything to the blog. If you wish to wade through it then start stepping ... However many of us do not and if you constantly quote them it defeats the purpose. There are numerous folks who use this feature and would appreciate your not underminding their right to do so! As for me I have 3 folks on ignore. I too am done!


Agreed!
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Quoting JLPR:
Are there any chances for something to develop out of the MLC that Erika abandoned?



Remember Ana
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No, I'm right.

I've yet to find any recordings of a storm in 1845.

But I did also add 1914 and 1983 for their respective records.



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I think that lone tower on her LLC is part of shear influencing it as the shear from her MLC is impacting it and causing to venture towards the MLC.
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Quoting StSimonsIslandGAGuy:
um 2007 had 2 Cat 5s
um I know!! its a joke, a funny, a light hearted comment!!, Glad to see you got it!
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Severe damage in central Baja being reported by the LATimes:


"Baja Bush Pilots has been monitoring the damage caused by hurricane/tropical storm Jimena in northern Baja California Sur. The situation, as reported earlier Thursday on Outposts, is bleak for many residents and disheartening for Baja aficionados who have grown fond of the region and its people.

Here's the midday update from the Bush Pilots, based not only on flyovers but reports from residents --before phone service went out, and in one instance a ham radio -- and members close to the situation:

-- Matancitas (Lopez Mateos): Almost 90% of structures are down or severely damaged. No water, power or telephone service.

-- Ciudad Constitucion: Most roofs are gone; severe damage to 70% of the buildings. No water, power or telephone service.

-- Loreto: No power or telephone service. Lines are down, trees are down. Buildings are damaged. The airport is closed.

-- Mulege: No water, power or telephone service. Water crested three feet above the bridge. Water was 2 feet deep in the fire station, which would mean that almost the entire town was flooded. There have been reports of loss of life. (Outposts has learned at least one man has died, according to authorities.)

-- Punta Chivato: One person indicates that the wind was over 100 mph before the indicator broke. Damage to almost everything. We should hear about the condition of the strip sometime today.

-- Santa Rosalia: Wall of water came down the canyon and through the town, washed cars, etc., into the ocean."
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Quoting Cotillion:


1845. No storms recorded.
as a matter fact you are wrong, the correct answer is 1983.
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Defiant - Erika has been labeled defiant.....she's in in defiance of the computer models..... Fascinating.

I'm with Weather456 - until the last nail is hammered in her coffin... eyes wide open. The Hot Tub in the GOM is a magnet... hope she fizzles b/4 she dips her foot... That's where her defiance has me worried.

She has demonstrated a will to survive -- not over yet....

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Nice footy of Jimena in Mex

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Though, can say 1914 with just the one storm.

Post-1960 though, it's 1983.
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Quoting Hurricane009:
probably this year... LOL


actually this year is above average so far

6th named storm in an average season doesnt form until September 12th
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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.