ATL GUSTAV: Tropical Depression - Discussion

[BigA]

My comment is not based on great shear knowledge, but it looks like the general consensus on the experimental tropical cyclone genesis potential fields model shows the TUTT lifting north in the next 48 hours, and a decrease of shear in the southern Caribbean.

[deltadog03]

Derek, I agree, there is some shear right now over the eastern Carrib...It looks fairly light and when through there..(as of now/forecasted) should give it a go at development.

[Gustywind]

Dr. Jeff Masters' WunderBlog

Last Updated: 14:18 GMT le 23 août 2008 —http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1037&tstamp=200808

Disturbance 94L approaching the Lesser Antilles
Heavy thunderstorms associated with a tropical wave (94L) near 11N, 57W, about 200 miles east of the Lesser Antilles Islands, have steadily grown more concentrated over the past day. This morning's QuikSCAT pass showed no closed circulation, but did show a pronounced wind shift associated with the disturbance. Top sustained winds were about 30 mph. Visible satellite loops show no evidence of rotation, and the area covered by heavy thunderstorms is relatively modest. The storm has moistened its environment considerably, and dry air should be less and less of a problem for the storm over the next few days. Wind shear has fallen to a modest 10 knots over 94L and is expected to remain in the low range, 5-10 knots, for the next four days. NHC is giving this system a medium (20%-50% chance) of developing into a tropical depression by Monday morning.

The forecast for 94L
The GFDL model, which with yesterday's run was developing 94L into a powerful hurricane that threatens Jamaica, is no longer developing the storm. The ECMWF, NOGAPS, and Canadian model all develop 94L. They foresee the system will enter the eastern Caribbean Sunday, jog northwest and affect the Dominican Republic on Tuesday, then develop into a tropical depression by Thursday near the Dominican Republic or eastern Bahama Islands. The wind shear forecast for the Caribbean calls for very low values of wind shear below 5 knots for most of the coming week (Figure 2). Residents of the Lesser Antilles can expect heavy rain and 40 mph wind gusts from 94L when it blows through Saturday night through Sunday. Residents of the Dominican Republic, Haiti, and Jamaica should keep a careful eye on this potentially dangerous disturbance.

Wind shear forecast for the Atlantic for 2 am EDT Monday August 25 2008, as predicted by this morning's 2 am EDT run of the GFS model. Very low values of winds shear (red colors) are predicted for the entire Caribbean and Gulf of Mexico. Winds shear values less than 8 m/s (approximately 16 knots, the three red colors) are conducive for troical storm formation.

[caribepr]

Worth keeping an eye on...

[SouthFloridawx]

Below 5kts huh? Could be an interesting week coming up.

[cycloneye]

[cycloneye]

Recon for monday if necessary.

000
NOUS42 KNHC 231430
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT SAT 23 AUGUST 2008
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 24/1100Z TO 25/1100Z AUGUST 2008
TCPOD NUMBER.....08-084

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY: POSSIBLE LOW LEVEL
INVEST NEAR 15.0N 67.5W AT 25/1800Z.

[masaji79]

94L is at such a low latitude that it looks like it will run into South America. Doesn't seem like there is too much of a chance of development at this moment.

[gatorcane]

time to maybe look at 95L

[ConvergenceZone]

The question is, when will 94L begin to pull up???? Usually these systems begin to pull up by now......Well, we always have 95L if this one doesn't make it.. I"m sure one of them will develop.

[CrazyC83]

Kinda reminds me of Felix with its position and projected track.

[cheezyWXguy]

time to maybe look at 95L

Are you joking me?
94L will easily clear south america...it already has. In addition, it is showing signs of at least a mid level circulation and has very favorable conditions ahead in about 1 a day.

[gatorcane]

I think 94L and 95L should be watched --- 95L is not getting the attention it may need though.....

[Ed Mahmoud]

Barfing out an outflow boundary. Not in any hurry to develop...

[Derek Ortt]

Recon for monday if necessary.

000
NOUS42 KNHC 231430
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT SAT 23 AUGUST 2008
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 24/1100Z TO 25/1100Z AUGUST 2008
TCPOD NUMBER.....08-084

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY: POSSIBLE LOW LEVEL
INVEST NEAR 15.0N 67.5W AT 25/1800Z.

this is the second consecutive day that recon has been delayed. Two days ago, the TCPOD has a possible flight for today... then tomorrow... now Monday

[cheezyWXguy]

Barfing out an outflow boundary. Not in any hurry to develop...

Yes, but this was not from the center. That was from the convection to the southeast, and that is dissipating, while new convection forms closer to what may be the mlc. This is the most persistence 94L has shown its whole life and does not deserve to be played down. This could become a rather strong storm if it does develop, and based on the strength of the ridge, probably will become a US threat down the road.

[jlauderdal]

Recon for monday if necessary.

000
NOUS42 KNHC 231430
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT SAT 23 AUGUST 2008
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 24/1100Z TO 25/1100Z AUGUST 2008
TCPOD NUMBER.....08-084

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY: POSSIBLE LOW LEVEL
INVEST NEAR 15.0N 67.5W AT 25/1800Z.

this is the second consecutive day that recon has been delayed. Two days ago, the TCPOD has a possible flight for today... then tomorrow... now Monday

maybe they are watching the wallet after following fay all over the place

[Ed Mahmoud]

Barfing out an outflow boundary. Not in any hurry to develop...

Yes, but this was not from the center. That was from the convection to the southeast, and that is dissipating, while new convection forms closer to what may be the mlc. This is the most persistence 94L has shown its whole life and does not deserve to be played down. This could become a rather strong storm if it does develop, and based on the strength of the ridge, probably will become a US threat down the road.

I'm not playing anything down, JB sees a Labor Day weekend hurricane threat to the SE US.

Just noting this does not seem well organized at the moment.

[cycloneye]

Will the John Hope rule apply here? The late John Hope said in his Tropical Updates that if a system didnt form before it reached the islands,then it will wait to form in the Western Caribbean.

[Blown Away]

Where is the circulation center? Is it near where the models initialize?