Tropical Storm Erika's future highly uncertain

By: Dr. Jeff Masters , 2:21 PM GMT on September 02, 2009

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The tropical wave we were calling Invest 94 finally decided to stop dawdling and become Tropical Storm Erika yesterday. However, Erika seems intent upon keeping us guessing about its intentions, as the storm's future track and intensity remain highly uncertain. After a modest burst of intensification to a 60 mph tropical storm last night, Erika has become quite disorganized this morning. The Hurricane Hunters found multiple swirling centers inside Erika early this morning, and the main center took a jump to the southwest to relocate itself under a batch of intense thunderstorms. The exact location and path of Erika remain uncertain at this point, and it is possible the storm will have another center relocation later today. Wind shear analyses from the University of Wisconsin diagnose a moderate 10 - 15 knots of shear over Erika, a decrease from yesterday. SSTs are warm, 29°C. Why, then, is Erika so disorganized? The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone. Upper air data from Guadeloupe and Saint Martin from last night show a complicated shear pattern in Erika's region, with 30 knot winds out of the south to southwest at 200 mb height, nearly calm winds between 300 - 500 mb, and northeasterly winds of 10 - 20 knots from the surface to 500 mb. Some extremely dry air with humidities near 10% was present in a thin layer near 600 mb on the Guadeloupe sounding, so dry air from the Saharan Air Layer is probably being injected by a northeasterly jet of wind into the core of Erika. The shear of 30 knots at the top of the storm is ripping away the heat and moisture Erika's thunderstorms are lifting there, and the result of the shear and dry air is a very disorganized tropical storm.

Erika is embedded in a weak steering current pattern, and the future track of the storm will depend greatly upon how strong the storm gets over the next few days. A stronger Erika will extend higher into the atmosphere and be steered more to the northwest by upper-level winds. A weaker Erika will be steered more by the low-level winds, which will keep the storm on a more westerly track. Given the complicated nature of the wind shear pattern in the region, it is difficult to forecast how strong Erika will get. Virtually anything can happen over the next five days, from dissipation (as forecast by the ECMWF model) to intensification to a Category 3 hurricane (as forecast by the HWRF model). Large-scale wind shear is expected to increase to 20 - 25 knots between 3 - 4 days from now, so Erika will have to deal with an increasing amount of adversity. The storm is a long-term threat to the Bahamas and U.S. East Coast, particularly if the storm stays weak over the next three days. Potential landfall solutions from the models range from Florida on Tuesday (GFS model) to North Carolina on Wednesday (Canadian model).


Figure 1. Morning image of Tropical Storm Erika, showing a false center over Guadaloupe--one of several surface swirls the Hurricane Hunters found in the storm.

Elsewhere in the tropics
The tropical wave off the coast of Africa we were watching on NHC's Tropical Weather Outlook as having a low chance of developing into a tropical depression has been done in by the dry air of the Sahara, and is no longer a threat to develop. A large and well-organized tropical wave will emerge from the coast of Africa on Thursday, and several of the models develop this low into a tropical depression by early next week. The remains of an old cold front off the coast of North Carolina could serve as a breeding ground for some tropical development Friday or Saturday, but anything that forms in this region would get swept quickly northeastward into New England by Sunday without enough time to become a tropical depression.

Hurricane Jimena nears Baja
Hurricane Jimena has steadily weakened over the past day, and is now down to a Category 2 hurricane with 105 mph winds. The storm should continue to steadily weaken over the next 24 hours as the waters under the hurricane cool from 28°C to 27°C. Jimena is battering a relatively unpopulated stretch of coast, and largely spared the tourist mecca on the southern tip of Baja. It now appears unlikely that moisture from Jimena will reach the Southwestern U.S., and the hurricane appears poised to stall out over Baja and die five days from now.


Figure 2. Hurricane Jimena on Tuesday, Sep. 1, 2009, as seen by NASA's MODIS instrument. Image credit: NASA Earth Observatory.

Baja's hurricane history
The most powerful hurricane on record to hit the west coast of Baja occurred last year, when Hurricane Norbert made landfall on the central Baja coast with sustained winds of 105 mph (Category 2) . Norbert's central pressure of 956 mb at landfall made it the 3rd strongest hurricane to hit the Pacific coast of Mexico since record keeping began in 1949. Norbert killed eight, knocked out power to 20,000 homes, and damaged or destroyed 40% of the homes on the islands of Margarita and Magdalena. Norbert crossed the Baja Peninsula and made landfall on Mainland Mexico as a Category 1 hurricane with 85 mph winds.

Only two major hurricanes have made landfall on Baja since record keeping began in 1949. Both hurricanes hit the east (Gulf of California) side of Baja. The first was Hurricane Olivia of 1967. Olivia made landfall on October 13, 1967 as a Category 3 hurricane with 125 mph winds. Due to its small size and the unpopulated region of coast it hit, damage was minimal. The second major hurricane was Hurricane Kiko, which made landfall on August 27, 1989, as a Category 3 hurricane with winds of 115 mph (minimal Category 3). Kiko was a small hurricane and hit a relatively unpopulated area, resulting in no loss of life and only scattered reports of damage.


Figure 3. A plot of all the major hurricanes to pass within 200 miles of Mexico's Baja Peninsula since 1949. Image credit: NOAA Coastal Services Center.

California fire webcams
As I discussed in yesterday morning's post, you can use our wundermap for Los Angeles with the fire layer turned on to see where the fire and smoke are located, and track the temperatures and winds during today's air pollution event. We also have two webcams with views of the fire: Altadena and Tujunga.

I'll have an update by 4pm this afternoon, when the data from the next hurricane hunter flight into Erika will be available.

Jeff Masters

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Quoting ConchHondros:


Dont forget Claudette


lol, I mean the Islands
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Quoting Weather456:
Ana now Erika, they sure like us this year.


Dont forget Claudette
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Quoting stormno:
why btwtx cause i know what im talking about i should be ignored...i have to say out of all the bloggers on here you are the most ignorant person i ever came across..you are a loser you dont want to learn and all you do is cause shit here..now i said my peace..thanks for the people that wanted me back its good to be back ..we have to focus on the eastern gom now ..could be trouble there in 72 hours...Stormno


First of all btwntx isn't all that bad. Second of all Erika won't go into the GOM looking at the track which is good news for people living on the Gulf coast. It will likely be a East coast storm depending on her strength. A stronger Erika would turn out to sea. A weak Erika will track more westerly impacting the US. As of now looking at the track it will be a weak TS.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting Weather456:


pulling a chris


Member Since: August 18, 2009 Posts: 0 Comments: 157
Ana now Erika, they sure like us this year.
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Quoting obxnagshead:
What would make this storm go north instead of more west?

A strong trough, or a weakness in the A/B high. Once it gets closer to the bahamas, a weaker trough can cause it to pull north, too.
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dynamical models do not need a center, unless there are moving nests.
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I see another burst of convention.
Member Since: May 10, 2007 Posts: 0 Comments: 960
For the js/exploit

Discovery Date = 09/02/2009

JS also implies Java, so might actually be SSD java loops.

It came up on mine. I am now running the flash loop instead. If it does not recur, that is probably the source... SSD.

Also, if you have not updated your virus/malware signature files, suggest you do so now and run a scan.
Member Since: September 9, 2008 Posts: 6 Comments: 3414
Quoting apocalyps:
Is texas a village with people in it?


Yes, but there always seems to be one member of the village missing. Of course, that missing village member seems to have a propensity to show up here on WU as a troll.
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DON'T X OUT OF THE FAKE VIRUS SCAN -
Click on the top of it to make sure that is the Primary window then Click Alt- F4
This is from the nice people at norton who told me it was my fault i had a virus that their stupid software let through.

ALT-F4 Closes the window and does not allow the virus Acess!
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The HWRF is overdone and not likely. Hpa is equivalent to millibars. You should be able to make the conversion knowing that.
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....reeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-ported...
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.
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As we can see, the false center is still looking strong on visual images, which means there are competeing LLCs. Erika won't strengthen til one of them wins out, more likely it'll be the one under the convection, but it'll take time.
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Quoting ConchHondros:
If anyone is in need of crow...I have about 200 that mob my feeders everyday...season is about to open I can bag as many as the blog needs :)


Good way to get ready for deer season...
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ERIKA 06L
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What would make this storm go north instead of more west?
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892. 789
make sure to have enough for the trolls
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Quoting CybrTeddy:
Erika: The storm that confuses me the most.
Apparently that spin you see just east of the islands is the old coc, and the new one is under the convection yet it relocated and still weakened.



pulling a chris
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Quoting Chiggy007:
My take is that this will end up in the Gulf through the FL Keys..
I expect the model to shift a little south..yet again..!
I have to give credit to the BAM suite of models - they have been consistently prediction a WEST-ward movement for the last 3 days now...GFS and GFDL are now tending to agree with the BAMs... :)

BAMS, BAMM, and BAMD are just very simple guidance models. While they are quick to run, they are just very basic, generalized guidance, and useful for looking at an overall steering flow. (and generally the BAMS is best for invests) Once a system gets initialized, the major, more complex models start to increase in skill.
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Quoting apocalyps:
Is texas a village with people in it?


Texas is a state in the US. Why are you asking?
Member Since: September 2, 2006 Posts: 110 Comments: 6878
888. JRRP

see you later... go to the uni
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TO: DRAKOEN


What do you think of the HWRF scenario?

and can you explain how Hpa equates to actual knots.
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Quoting Chiggy007:
My take is that this will end up in the Gulf through the FL Keys..
I expect the model to shift a little south..yet again..!
I have to give credit to the BAM suite of models - they have been consistently prediction a WEST-ward movement for the last 3 days now...GFS and GFDL are now tending to agree with the BAMs... :)
i have been noticing that chiggy, what about intensity?
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Per NRL.
06LERIKA.40kts-1008mb
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Quoting antonio28:


Thanks, so the flood will be the problem as always.


yea, no doubt about that
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Quoting ncstorm:
is anyone getting the virus scan alert when opening weatherunderground


i had that the other night... close it fast it is a fake scan, took me over an hr to get my pc back in order....do not down load it.. again do not down load it....
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----- Current Analysis -----
Date : 02 SEP 2009 Time : 164500 UTC
Lat : 16:36:04 N Lon : 60:37:32 W


CI# /Pressure/ Vmax
3.2 / 999.9mb/ 49.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.7 2.6 2.2
Weakening Flag : ON
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Quoting obxnagshead:
Anyone think this is going to be an OBX storm?


Maybe, we'll just have to wait and see.
Member Since: September 2, 2006 Posts: 110 Comments: 6878
Quoting Weather456:


unlikely


Thanks, so the flood will be the problem as always.
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Quoting obxnagshead:
Anyone think this is going to be an OBX storm?
It was looking as if that was a possibility yesterday, but from what I've seen today, I'd say no.
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Erika: The storm that confuses me the most.
Apparently that spin you see just east of the islands is the old coc, and the new one is under the convection yet it relocated and still weakened.

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12z Nogaps similar in terms of track to cmc.
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Two very fine examples of Middle English lexicon there, Flood!

It definitely has taken on the latter definition in contemporary usage.

Erika is really struggling per ADT. It does have the rapid dissipation flag rescinded for the time being, though. Probably because of the centre positioning on the interpolation.
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Anyone think this is going to be an OBX storm?
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I've gotten into the habit of not making predictions with a storm. I generally just cite what the major models and the NHC are forecasting, and give rough guesstimates on how those forecasts are doing. This way, I never have to eat crow - its kinda stringy, and is very gamey tasting.
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Quoting Weather456:



yea...no old fashion forecasting just following models like when they were going out sea. *shakes head*
Thats what we need more of right now, old fashion forecasting. These models do not have a grasp on Erika right now! They are useless at the moment!!
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If anyone is in need of crow...I have about 200 that mob my feeders everyday...season is about to open I can bag as many as the blog needs :)
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My take is that this will end up in the Gulf through the FL Keys..
I expect the model to shift a little south..yet again..!
I have to give credit to the BAM suite of models - they have been consistently prediction a WEST-ward movement for the last 3 days now...GFS and GFDL are now tending to agree with the BAMs... :)
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Quoting TriniGirl26:


lol....will u like a helping? I'm willing to share :P lol


nope, don't it thus far.
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Quoting Weather456:
I cant remember the last time a tropical cyclone like Erika dished out so many crow.


lol....will u like a helping? I'm willing to share :P lol
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Quoting hurricane23:


I somwhat concur with that statement based on the current model trends.



yea...no old fashion forecasting just following models like when they were going out sea. *shakes head*
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Quoting Floodman:
Hey, keys33070, you asked me a while back what tosspot meant? It comes from middle English and means, pretty much, someone who is addled by drink...recently it's become synonomous with a wanker, who is addled by something else entirely



Ahh that explains everything...I now know what's been ailing me all these years...I'm a tosspot wanker...Thanks Dr. Flood :)
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Quoting Floodman:
Hey, keys33070, you asked me a while back what tosspot meant? It comes from middle English and means, pretty much, someone who is addled by drink...recently it's become synonomous with a wanker, who is addled by something else entirely


LOL. I actually just laughed out loud here in the office. thanks, flood!
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is anyone getting the virus scan alert when opening weatherunderground
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Quoting apocalyps:
Never,ever in my lifetime i have seen such a blow up of convention.
Erika is almost in the Carribbean.
Is Texas in the carribbean?
Yeah,...Mon...The Texas Antilles...its irie mon...
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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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