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 Chiggy007:
Alaina.. you have been reported to Admin..not sticking to tropics....!!!!!!!


You have been reported to admin for not staying on topic.
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Time: 17:58:00Z
Coordinates: 16.3N 60.5W

Acft. Static Air Press: 959.4 mb (~ 28.33 inHg)
Acft. Geopotential Hgt: 424 meters (~ 1,391 feet)
Extrap. Sfc. Press: 1007.1 mb (~ 29.74 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 217° at 14 knots (From the SW at ~ 16.1 mph)
Air Temp: 23.0°C (~ 73.4°F)
Dew Pt: 18.9°C (~ 66.0°F)
Peak (10s) Flt. Lvl. Wind: 15 knots (~ 17.2 mph)
SFMR Peak (10s) Sfc. Wind: 26 knots (~ 29.9 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
(*) Denotes suspect data
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959. 789
Quoting LBAR:
What kind of clouds are those streaming southeast/east away from Erika ?
that was from 2006
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Quoting Drakoen:
The HWRF is overdone and not likely. Hpa is equivalent to millibars. You should be able to make the conversion knowing that.


Yeah, right. I'm lucky I know how to add!
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Quoting jeffs713:

Seriously? You should be reporting a good third of the blog then. I reserve the reporting feature for people who spam, are disruptive, or being completely inappropriate (ie: personal attacks). Alaina did none of those, and regularly contributes to the blog.


My gosh thank you!
Member Since: August 2, 2006 Posts: 0 Comments: 1240
Q & A for NHC - James Franklin
Member Since: July 3, 2005 Posts: 430 Comments: 130817
Quoting Floodman:


You can beat it...you just have to be patient and know the registry very well. It also helps to have an ultimate bootdisk to start the machine with tools but not off the HDD


I have a two good UBB's (Hiren's was one of them) and I tried the off HDD scans. It finds the virus, but the darn thing keeps coming back. I even deleted and reinstalled a whole bunch of infected .DLL's and .SYS files from the windows/system32 directory. I at least got the wallpaper back permanently and at times I can get the resolution back to normal, but as soon as the computer goes online - bam... I just copied the data off, a reformat was quicker in the long run.
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A more mellow version for the older folks on here.
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Shear looks promising ahead of the 20-30kt shear. Could see some strengthening.


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950. LBAR
Quoting IKE:
OMG...this airport is within 6 miles of the latest center on Erika. Note the winds...

"Le Raizet Airport, GP (Airport)
Updated: 47 min 23 sec ago
Mostly Cloudy
86 °F
Mostly Cloudy
Humidity: 79%
Dew Point: 79 °F
Wind: 7 mph from the ESE
Pressure: 29.83 in (Falling)
Heat Index: 99 °F
Visibility: 6.2 miles
UV: 9 out of 16
Clouds:
Scattered Clouds 1200 ft
Mostly Cloudy 4000 ft
(Above Ground Level)
Elevation: 26 ft"


Maybe that airport is in the eye! Teehee
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IKE - They already did.

36 knots
(~ 41.4 mph)
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isee convection starting to pull towards and around "the so called coc" mmmmmmm..... could this mean .... nah not possible!!
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thank you :o)
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Quoting Chiggy007:
Alaina.. you have been reported to Admin..not sticking to tropics....!!!!!!!

Seriously? You should be reporting a good third of the blog then. I reserve the reporting feature for people who spam, are disruptive, or being completely inappropriate (ie: personal attacks). Alaina did none of those, and regularly contributes to the blog.
Member Since: August 3, 2008 Posts: 16 Comments: 5895
944. Relix
Quoting Weather456:


the most i'm expecting is alot of rain, beneficial rains


Me too. Should cool down the days ahead, leave some water supplies full, etc, etc, etc. Not much more than that.
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943. IKE
OMG...this airport is within 6 miles of the latest center on Erika. Note the winds...

"Le Raizet Airport, GP (Airport)
Updated: 47 min 23 sec ago
Mostly Cloudy
86 °F
Mostly Cloudy
Humidity: 79%
Dew Point: 79 °F
Wind: 7 mph from the ESE
Pressure: 29.83 in (Falling)
Heat Index: 99 °F
Visibility: 6.2 miles
UV: 9 out of 16
Clouds:
Scattered Clouds 1200 ft
Mostly Cloudy 4000 ft
(Above Ground Level)
Elevation: 26 ft"
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting Relix:
They will probably downgrade it at 5PM. Should past south of PR since it's so weak leaving some rains and gusty conditions here in PR. Not so much thought. Right now my serving of crow is in the fridge, let's see how it pans out. Not expecting winds over 30MPH at all in PR.


the most i'm expecting is alot of rain, beneficial rains
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Quoting hurricane23:


Dynamical models do not need a center, unless there are moving nests.
Quoting hurricane23:


Dynamical models do not need a center, unless there are moving nests.
How would they do it before computer models? I doubt it had anything to do with nests! Look im not saying models are not very useful in forecasting 99% of storms but this one is different, and i was hoping someone with some old school experience could help.
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Interesting area emerging off Africa.
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Quoting dolphingalrules:
what is a obx storm..in simple words


An OBX storm is a TS or Hurricane that hits the Outer Banks of NC.
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I am still holding on to my prediction from yesterday at around this time. This storm will pass very close to puerto rico and may have little interaction with the north coast of hispanola. Might miss florida completely
on its way to the GOM or it may began a northerly turn over the state of florida
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Quoting Dakster:


BTW - I just finished trying to fix a computer with that particular virus on it. The only way to succeed if it entrenches itself is to reformat the hard drive and reinstall from scratch. I would like to be alone, in a room, with the person that wrote that virus... 'enuf said.


You can beat it...you just have to be patient and know the registry very well. It also helps to have an ultimate bootdisk to start the machine with tools but not off the HDD
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting dolphingalrules:
what is a obx storm..in simple words


One that hits the "outer banks" of NC... obx = outer banks.
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Quoting justalurker:




one of my favorite intriguing radar series :)
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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 :)
Yes,Please....I am in need of much,much crow......We our having delicious crow buffet extravaganza......including our new Erika Crunchy Crow.....:):):)Quite a few of the models are showing Erika strengthening over the Southern Bahama Islands. It looks interesting.
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.ERIKA NEAR GUADELOUPE...
2:00 PM AST Wed Sep 2
Location: 16.2°N 61.1°W
Max sustained: 40 mph
Moving: W at 10 mph
Min pressure: 1008 mb
Member Since: Posts: Comments:
931. Relix
They will probably downgrade it at 5PM. Should past south of PR since it's so weak leaving some rains and gusty conditions here in PR. Not so much thought. Right now my serving of crow is in the fridge, let's see how it pans out. Not expecting winds over 30MPH at all in PR.
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000
ABNT20 KNHC 021755
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED SEP 2 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM ERIKA LOCATED VERY NEAR GUADELOUPE IN THE LEEWARD ISLANDS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

PUBLIC ADVISORIES ON ERIKA ARE ISSUED UNDER WMO HEADER WTNT31 KNHC
AND UNDER AWIPS HEADER MIATCPAT1. FORECAST/ADVISORIES ARE ISSUED
UNDER WMO HEADER WTNT21 KNHC AND UNDER AWIPS HEADER MIATCMAT1.

$$
FORECASTER BLAKE


Nothing new.
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Quoting FLWeatherFreak91:
It was looking as if that was a possibility yesterday, but from what I've seen today, I'd say no.
what is a obx storm..in simple words
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The convention is astounding!
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Alaina.. you have been reported to Admin..not sticking to tropics....!!!!!!!
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Quoting tropicfreak:


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.


Just ignore stormno, he's nothing more than a troll that downcasts systems to get the blog ralled up.
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have you read the 2:00 PM advisory???
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924. IKE
MAXIMUM SUSTAINED WINDS REMAIN NEAR 40 MPH...65 KM/HR...WITH HIGHER
GUSTS. HOWEVER...SATELLITE IMAGES INDICATE THE STORM MAY BE
WEAKENING.


Oops...I sense a downgrade coming if recon can't find TS winds.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting NoNamePub:
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!


BTW - I just finished trying to fix a computer with that particular virus on it. The only way to succeed if it entrenches itself is to reformat the hard drive and reinstall from scratch. I would like to be alone, in a room, with the person that wrote that virus... 'enuf said.
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Quoting ConchHondros:


Dont forget Claudette


Not sure but I think he's referencing the ladies who paid our islands a visit. Claudette did not make an appearance for us. :)
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Quoting NoNamePub:
Flood - I plan on being tosspot this evening...HAHA Does that work -

Whats your opinion man - Erika going to make it to dmax?


Yes, I think she will; I base that on past experience and the data itself...whether we'll be talking about her tomorrow other than apocryphally is anyone's guess

Have fun tossing your pot, lad!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Jeffs:

Yes I know the about the details of BAM models... simplistic or not they have been performing the best for 94L/Erika - and generally if all three BAM flavors (BAMS, BAMM, BAMD) are in agreement then one needs to give a little more weight...

They also didn't too bad with IKE last year...

Just my take..
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...SUMMARY OF 200 PM AST INFORMATION...
LOCATION...16.2N 61.1W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST OR 265 DEGREES AT 10 MPH
MINIMUM CENTRAL PRESSURE...1008 MB


Still at 40mph.
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Quoting Patrap:
I've got anew Neighbor Uptown I see.

Actress Sandra Bullock purchases home in New Orleans' Garden District
by Rebecca Mowbray, The Times-Picayune


Tuesday September 01, 2009, 10:20 PM
AP Photo/Chris Pizzello

Actress Sandra Bullock, who has donated generously to Warren Easton Senior High School since Hurricane Katrina, has purchased a historic home in the Garden District from entrepreneur John Russell Lee Sr., whose I CAN Learn educational software was at the center of the Mose Jefferson trial.



OMG I love her. Shes one of my fave actresses.
Member Since: August 2, 2006 Posts: 0 Comments: 1240
Quoting hurricane23:
dynamical models do not need a center, unless there are moving nests.

True. But their forecasting skill is greatly increased once a center is initialized into the model.
Member Since: August 3, 2008 Posts: 16 Comments: 5895
914. IKE
...ERIKA NEAR GUADELOUPE...
2:00 PM AST Wed Sep 2
Location: 16.2°N 61.1°W
Max sustained: 40 mph
Moving: W at 10 mph
Min pressure: 1008 mb
Member Since: June 9, 2005 Posts: 23 Comments: 37860
913. LBAR
What kind of clouds are those streaming southeast/east away from Erika ?
Member Since: Posts: Comments:
000
WTNT31 KNHC 021754
TCPAT1
BULLETIN
TROPICAL STORM ERIKA INTERMEDIATE ADVISORY NUMBER 4A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062009
200 PM AST WED SEP 02 2009

...ERIKA NEAR GUADELOUPE...

A TROPICAL STORM WARNING REMAINS IN EFFECT FOR GUADELOUPE...ST.
MARTIN...ST. BARTHELEMY...ANTIGUA...BARBUDA...MONTSERRAT...ST.
KITTS...NEVIS...ANGUILLA...ST. MAARTEN...SABA...AND ST. EUSTATIUS.

INTERESTS ELSEWHERE IN THE LEEWARD ISLANDS...THE U.S. AND BRITISH
VIRGIN ISLANDS...AND PUERTO RICO SHOULD MONITOR THE PROGRESS OF
ERIKA. TROPICAL STORM WATCHES OR WARNINGS COULD BE REQUIRED FOR A
PORTION OF THESE AREAS LATER TODAY.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA
OUTSIDE OF THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR NATIONAL METEOROLOGICAL SERVICE.

AT 200 PM AST...1800 UTC....THE CENTER OF THE POORLY ORGANIZED
TROPICAL STORM WAS ESTIMATED TO BE NEAR LATITUDE 16.2 NORTH...
LONGITUDE 61.1 WEST OR VERY NEAR GUADELOUPE IN THE LEEWARD ISLANDS.

ERIKA IS MOVING TOWARD THE WEST NEAR 10 MPH...17 KM/HR. A WEST-
NORTHWESTWARD MOTION IS EXPECTED TO BEGIN LATER TODAY. ON THE
FORECAST TRACK...ERIKA WILL BE MOVING THROUGH THE LEEWARD ISLANDS
TONIGHT AND TOMORROW.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 40 MPH...65 KM/HR...WITH HIGHER
GUSTS. HOWEVER...SATELLITE IMAGES INDICATE THE STORM MAY BE
WEAKENING. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS
CURRENTLY EN ROUTE TO DETERMINE THE INTENSITY OF ERIKA. LITTLE
CHANGE IN STRENGTH IS FORECAST TODAY WITH SOME SLIGHT
RESTRENGTHENING POSSIBLE TOMORROW.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 105 MILES...165 KM
MAINLY WELL TO THE EAST OF THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB...29.77 INCHES.

ERIKA IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 2 TO 4
INCHES OVER MUCH OF THE LESSER ANTILLES DURING THE NEXT COUPLE OF
DAYS...WITH ISOLATED MAXIMUM AMOUNTS OF 6 INCHES POSSIBLE. OVER
PUERTO RICO...3 TO 5 INCHES OF RAIN ARE POSSIBLE DURING THE NEXT
FEW DAYS...WITH ISOLATED MAXIMUM AMOUNTS OF 8 INCHES.

...SUMMARY OF 200 PM AST INFORMATION...
LOCATION...16.2N 61.1W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST OR 265 DEGREES AT 10 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
500 PM AST.

$$
FORECASTER BLAKE/FRANKLIN



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Quoting ConchHondros:


Dont forget Claudette


lol, I mean the Islands
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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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