ATL : TROPICAL DEPRESSION ERIKA (06L)

[otowntiger]

I think you'll be just fine in Baton Rouge.

Well these shifts mean I will definitely be keeping an eye on this one.

And you'll be just fine in Houston too!

[Aric Dunn]

seems to have lost the good inflow it did yesterday

a low level easterly jet associated with a SAL surge does that every time. I have no clue what this will do now

But seriously, you can't honestly say you're surprised at this system's waning and diminishing once again can you?

waning is much different than diminishing or dieing..

this is simply confused or sick .. lol

clearly some dynamics we are just not capable of predicting have taken place and exactly how it pans out is a mystery. we can only make a series of short term forecast on the time scale of hours rather than days that eventually lead to a semi-complete picture of the future track.

[HURAKAN]

Tropical Storm Erika's future highly uncertain

Posted by: JeffMasters, 2:21 PM GMT on September 02, 2009
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.

[Stormcenter]

I agree with Frank2 at this moment Erika "does not" look good.
What looks like the center is completely exposed.

You must be speaking of someone else - this has never looked that impressive, other than a few days ago when the MLC was showing decent banding, but other than that, it's similar to Danny when it comes to disorganization, so don't be surprised if they do downgrade it, since it's very poorly organized (even for a TD) at this time...

Frank

This is a joke right? You aren't serious...you can't be...

[Sanibel]

I wouldn't expect too much with the dry air riding ahead and possible island interaction.


2009 is undermining these systems with sick air layered shear that robs them of their structure and moisture.

['CaneFreak]

seems to have lost the good inflow it did yesterday

a low level easterly jet associated with a SAL surge does that every time. I have no clue what this will do now

But seriously, you can't honestly say you're surprised at this system's waning and diminishing once again can you?

waning is much different than diminishing or dieing..

this is simply confused or sick .. lol

clearly some dynamics we are just not capable of predicting have taken place and exactly how it pans out is a mystery. we can only make a series of short term forecast on the time scale of hours rather than days that eventually lead to a semi-complete picture of the future track.

Yeah...until this thing throws out the dry air thats been injected into it (SOUNDINGS DON'T LIE)...you can forget strengthening...this is going to be an interesting discussion...

[Stormcenter]

Jeff Masters= sitting on the fence.

[otowntiger]

For now, the "All Clear For Florida" has been discontinued.

While that may be true it appears that the storm will not develop into anything to get too worked up over. Certainly right now she's not feeling too good and no one really knows what she could do intensity wise.

['CaneFreak]

I agree with Frank2 at this moment Erika "does not" look good.
What looks like the center is completely exposed.

You must be speaking of someone else - this has never looked that impressive, other than a few days ago when the MLC was showing decent banding, but other than that, it's similar to Danny when it comes to disorganization, so don't be surprised if they do downgrade it, since it's very poorly organized (even for a TD) at this time...

Frank

This is a joke right? You aren't serious...you can't be...

see the picture above your post...its not exposed

[Bocadude85]

For now, the "All Clear For Florida" has been discontinued.

While that may be true it appears that the storm will not develop into anything to get too worked up over. Certainly right now she's not feeling too good and no one really knows what she could do intensity wise.

Exactly no one knows what she will really do.. so how can you say she wont be anything to get worked up about?

[Aric Dunn]

Tropical Storm Erika's future highly uncertain

Posted by: JeffMasters, 2:21 PM GMT on September 02, 2009
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.

That is by far the best analysis i have read from him ..
and its absolutely dead on.. you should just keep re-posting that every page.. lol

[ConvergenceZone]

I guess from what Jeff Masters is saying is that in order to get a recurve the storm will need to intensify, but if it doesn't intensify and just remains a weak storm, then the east coast may be a threat

['CaneFreak]

" 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."

YESSSS...GOOD POST...Finally, someone with some sense

[HURAKAN]

While that may be true it appears that the storm will not develop into anything to get too worked up over. Certainly right now she's not feeling too good and no one really knows what she could do intensity wise.

I don't trust anything that moves towards the Bahamas

[knotimpaired]

For now, the "All Clear For Florida" has been discontinued.

While that may be true it appears that the storm will not develop into anything to get too worked up over. Certainly right now she's not feeling too good and no one really knows what she could do intensity wise.

I cannot read who the blue line is that has it coming right over us. Can anyone read it and are they reliable?

[HURAKAN]

634
WTNT31 KNHC 021447
TCPAT1
BULLETIN
TROPICAL STORM ERIKA ADVISORY NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062009
1100 AM AST WED SEP 02 2009

...ERIKA APPROACHING THE LEEWARD ISLANDS...

AT 11 AM AST...1500 UTC...THE GOVERNMENT OF FRANCE HAS ISSUED A
TROPICAL STORM WARNING FOR GUADELOUPE. A TROPICAL STORM WARNING IS
NOW IN EFFECT FOR GUADELOUPE...ST. MARTIN AND ST. BARTHELEMY.

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

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24 HOURS.

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 1100 AM AST...1500 UTC...THE CENTER OF TROPICAL STORM ERIKA WAS
ESTIMATED TO BE NEAR LATITUDE 16.5 NORTH...LONGITUDE 60.4 WEST OR
ABOUT 100 MILES...165 KM...EAST-SOUTHEAST OF 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 HAVE DECREASED TO NEAR 40 MPH...
65 KM/HR...WITH HIGHER GUSTS. 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 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 1100 AM AST INFORMATION...
LOCATION...16.5N 60.4W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST OR 275 DEGREES AT 10 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 200 PM AST FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 500
PM AST.

$$
FORECASTER BLAKE/FRANKLIN

893
WTNT41 KNHC 021447
TCDAT1
TROPICAL STORM ERIKA DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062009
1100 AM AST WED SEP 02 2009

VISIBLE SATELLITE IMAGES AND AIR FORCE RESERVE HURRICANE HUNTER
DATA SHOW THAT ERIKA IS A POORLY ORGANIZED SYSTEM. THERE ARE
MULTIPLE SWIRLS APPARENT ON THE SATELLITE IMAGERY ROTATING IN THE
LARGER CIRCULATION ENVELOPE WITH A MEAN CENTER TO THE WEST OF THE
DEEP CONVECTION. THE SFMR EARLIER REPORTED WINDS OF ABOUT 35
KT...WHICH IS IN GOOD AGREEMENT WITH SATELLITE INTENSITY
ESTIMATES...SO THAT VALUE WILL BE USED AS THE INITIAL INTENSITY.

VERTICAL WIND SHEAR HAS INCREASED EARLIER THAN EXPECTED...WITH CIMSS
DIAGNOSING ABOUT 15-20 KT OF SHEAR. AT FIRST GLANCE...THE SHEAR DOES
NOT APPEAR TO BE TOO STRONG OVER THE SYSTEM WITH SOUTH OR
SOUTHEASTERLY WINDS REPORTED AT 200 MB OVER THE NORTHERN LEEWARD
ISLANDS. HOWEVER...UPPER-AIR DATA FROM GUADELOUPE AND ST. MAARTEN
SUGGEST THAT THE SHEAR IS PRIMARILY COMING FROM SOUTHWESTERLY WINDS
BETWEEN 300 MB-250 MB...AND THIS IS APPARENTLY UNDERCUTTING THE
OUTFLOW LAYERS AT 200 MB AND ABOVE. MOST OF THE GLOBAL MODELS DO
NOT SHOW MUCH RELAXATION OF THIS SHEAR...AND ACTUALLY SHOW IT
INCREASING SIGNIFICANTLY IN A COUPLE OF DAYS. DESPITE ALL THIS
SHEAR...ALL RELIABLE GUIDANCE RESTRENGTHENS THIS SYSTEM TO NEAR
HURRICANE STRENGTH IN A FEW DAYS. THIS REINTENSIFICATION
DOES NOT SEEM VERY LIKELY AND THE NHC FORECAST IS MUCH LOWER THAN
THE GUIDANCE. GIVEN THE POSSIBLE SHEAR DURING THE FORECAST
PERIOD...IT WOULD NOT BE SURPRISING IF ERIKA DISSIPATED.

A 24-HOUR MOTION IS ABOUT 275/9. A WEST-NORTHWESTWARD TRACK IS
PREDICTED TO RESUME AS THE STORM MOVES TO THE SOUTH OF A WEAK
SUBTROPICAL RIDGE FOR A COUPLE OF DAYS. THIS RIDGE IS FORECAST TO
WEAKEN SOMEWHAT IN A FEW DAYS...AND A NORTHWESTWARD MOTION IS
POSSIBLE BY THE END OF THE FORECAST. THE OFFICIAL FORECAST HAS BEEN
SHIFTED LEFT OF THE PREVIOUS ONE AND IS LEFT OF THE DYNAMICAL
CONSENSUS DUE TO THE ANTICIPATION OF ERIKA REMAINING WEAK. IT
SHOULD BE EMPHASIZED THAT...OVERALL...THIS IS A LOW-CONFIDENCE
TRACK FORECAST.

TROPICAL STORM WATCHES COULD BE REQUIRED FOR THE U.S. AND BRITISH
VIRGIN ISLANDS AS WELL AS PUERTO RICO LATER TODAY.


FORECAST POSITIONS AND MAX WINDS

INITIAL 02/1500Z 16.5N 60.4W 35 KT
12HR VT 03/0000Z 16.9N 61.5W 35 KT
24HR VT 03/1200Z 17.4N 62.8W 40 KT
36HR VT 04/0000Z 18.0N 64.2W 45 KT
48HR VT 04/1200Z 18.6N 65.5W 40 KT
72HR VT 05/1200Z 20.0N 68.5W 35 KT
96HR VT 06/1200Z 21.5N 71.5W 30 KT
120HR VT 07/1200Z 23.5N 73.5W 30 KT

$$
FORECASTER BLAKE/FRANKLIN

[Stormcenter]

We can't even get this thing past the islands and you have it the GOM already.
If it made it in there (GOM) it would be short lived if it survived.

The center found by RECON is under the convection or very close to it, not the one over the Lesser Antilles. Strong convection is developing over the estimated position of the center, therefore, the NHC won't downgrade the system to TD without RECON information.

yeah even though there is clearly a vortex rotating sw the ball of convection that is firing is the main center or at least more dominate.

the models are just not going to have a easy time at all for the 12z run this is farther south than any model except the bam models from 3 days ago when they had it entering the NE carrib.

expect yet another shift west and south .. possibly across DR which does not bode well for strengthening...

not withstanding the potential for this entering the gulf if it hold together is increasing quickly and of course the bahamas and florida before that.

[Sanibel]

10% humidity air injected into a system will really weaken the fuel mix.


The system still has enough energy to make that healthy upper outflow to the south quadrant.

[HURAKAN]

...SUMMARY OF 1100 AM AST INFORMATION...
LOCATION...16.5N 60.4W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...WEST OR 275 DEGREES AT 10 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

['CaneFreak]

10% humidity air injected into a system will really weaken the fuel mix.


The system still has enough energy to make that healthy upper outflow to the south quadrant.