ATL: TROPICAL DEPRESSION BONNIE - DISCUSSION

[Explodo]

For everyone that was so bullish the euro models over the GFS, not one of the 50 member euro ensemble develops it. Does this mean everyone is going to become GFS lubbers?

Why does everyone think the Euro is god. It can be wrong sometimes. Other models can be right. I don't think the EURO has a clue and the only systems it does develop are distinctly strong systems that are guaranteed to form.

well...from what can tell, differrent models tend to be more accurate given different set ups. Seems this year is favoring the Euro in terms of what numerical inputs drive the model. Watching the Euro perform this year (And it's been a difficult year to begin with) it's been really accurate IMO. Thus, until another model starts performing better, The Euro is the Delphi of models.

If the more experienced folks can correct me...please do...I need the education

[cycloneye]

Discussions about models can continue in the 97L models thread.

[HURAKAN]

Great vantage point

[gatorcane]

Doesn't seem to be moving much the past several hours looking at the floater. Does anybody agree with this observation?

Also convection seems to be on the increase.

[Meso]

Looking very good, taking on that 'tropical depression' look. Don't think it will be too long before proper banding takes place.

[Frank2]

I won't bother with 97L until Thursday. Right now there is nearly 30 knots of wind shear by it due to that stationary TUTT/ULL that's been there for over a month.

That's also my opinion (about the TUTT/ULL), though as Gatorcane mentioned that feature is forecast to move WNW as a ridge builds in - we'll see, though right now the ULL is pretty formidable looking...

Frank

[tolakram]

Loop: http://wwwghcc.msfc.nasa.gov/cgi-bin/ge ... mframes=15

Does not appear to be any better organized to my eyes.

Observations:

http://www.wunderground.com/wundermap/? ... .7&zoom=10

I'm curious how people are measuring the wind shear.

[SFLcane]

Convection near greatest vorticity...

[Blown Away]

Doesn't seem to be moving much the past several hours looking at the floater. Does anybody agree with this observation?

Also convection seems to be on the increase.

It's been hovering around for almost 24 hours now and I think this delay will be trouble for Bahamas and SFL/NE GOM down the road. Hopefully it's nothing more than a wave.

[cycloneye]

Below is this mornings Dr Jeff Masters discussion about the future of 97L:

Forecast for 97L
The storm is in a fairly straightforward steering current environment, and 97L should progress steadily to the west-northwest through Saturday. The rains from 97L's thunderstorms will bring the threat of flooding to the Dominican Republic today and Wednesday, and to Haiti on Wednesday and Thursday. Heavy rains from 97L will begin moving into eastern Cuba, the Turks and Caicos Islands, and the eastern Bahamas on Wednesday, and South Florida can expect heavy rains to arrive as early as Thursday night. We do have several models developing 97L into a tropical depression or tropical storm. The GFS and HWRF both take 97L to tropical storm status over the Bahamas by Thursday, with the storm then tracking over South Florida on Friday and entering the Gulf of Mexico on Saturday. The NOGAPS is similar, but portrays a weaker system. All of these models foresee a threat to the oil spill region by Saturday night or Sunday, with the storm making a second landfall somewhere between the Florida Panhandle and Louisiana. One factor potentially aiding the storm will be the Madden-Julian oscillation, which currently favors upward motion over the Gulf of Mexico and Caribbean. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased. Also in favor of development are the warm ocean temperatures of 29°C. The SHIPS model predicts shear will remain moderate, 10 - 20 knots, over the next 4 - 5 days, and I believe the primary detriment to development of 97L over the next two days will be the presence of dry, stable air in its path over the Bahamas, thanks to the upper-level low to the north of the Dominican Republic. NHC is giving 97L a 40% chance of developing into a tropical depression by Thursday, which is a reasonable forecast. I think there is a 60% chance 97L will eventually become Tropical Storm Bonnie, sometime in the next five days. Sudden rapid development today or on Wednesday is unlikely, due to the dry air over the Bahamas, and I put the odds of 97L making it to hurricane strength before reaching Florida at 10%. There is a better chance that 97L could attain hurricane strength in the Gulf of Mexico, perhaps 20%. These probabilities will depend heavily upon how long 97L (or Bonnie) spends over land or interacting with land over the next four days, which is very uncertain.

[Bocadude85]

I am not sure I see what everyone else is talking about.. all I see is a pulsing tropical wave.

[HurrMark]

Still looks pretty disorganized. I would think that it might have a shot to develop into something by Wed or Thurs. If nothing develops by then, Its forward speed will be critical to see how much time it has before it runs aground...looks like another Gulf weather system at this point.

[Blown Away]

I am not sure I see what everyone else is talking about.. all I see is a pulsing tropical wave.

That's what we see rate now, but compared to yesterday we now have a wave with some model support bringing a TS or hurricane to Bahamas, SFL, and GOM. More importantly the NHC continues to increase the probability of development. 97L was not expected to hang out over Eastern PR for a day.

[Frank2]

The bottom line is that as long as that ULL/TUTT feature is to the west, 97L will have a hard time doing more than it's doing now...

http://www.goes.noaa.gov/HURRLOOPS/huwvloop.html

P.S. The WV is my favorite loop, because it can show what the other loops cannot, and it's those "invisible" factors that make all the difference - I'm sure the NHC is taking the ULL into account as we speak (that, or they're drinking a coka-cola - lol)...

[poof121]

Can someone answer this question for me? Why is the CIMSS product showing westerly shear, but the visible satellite seems to be showing the clouds moving towards the west?

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Thanks.

[Comanche]

The bottom line is that as long as that ULL/TUTT feature is to the west, 97L will have a hard time doing more than it's doing now...

http://www.goes.noaa.gov/HURRLOOPS/huwvloop.html

P.S. The WV is my favorite loop, because it can show what the other loops cannot, and it's those "invisible" factors that make all the difference...

Mine as well, and I agree 100%.

[Comanche]

Snippet from Jeff this am-

97L:

Disorganized area of showers and thunderstorms is the result on a tropical wave interacting with a upper level low near Puerto Rico. Radar images out of San Juan do not suggest a surface circulation has developed although there does appears to be a mid level spin near the eastern coast of Puerto Rico this morning. Forecast models have become more aggressive overnight in developing this system as it moves generally toward the W or WNW. Hard to determine at this time where/if any surface circulation will develop so guidance is not of much use. Steering pattern suggest a general WNW track over the next 2-3 days with the system nearing the Cuba/S FL/Bahamas area by the end of this week and possibly entering into the SE/E Gulf of Mexico early next week.

[Frank2]

Glad that Jeff Masters is acknowleding the ULL factor since that's the primary reason for the flare-up...

[Gustywind]

LATEST

[Frank2]

Thanks, but those photos are misleading, because what is seen are mostly high clouds - look at the difference:

http://www.ssd.noaa.gov/goes/flt/t1/vis-l.jpg