ATL: GABRIELLE - Remnants - Discussion

['CaneFreak]

Sounds familiar. This is what I wrote last night:

The height gradient from the upper level high in the eastern Caribbean and the upper level low to the north is causing a BUNCH of shear in the path of this disturbance (moving northwest). If you want this thing to develop, you better hope the upper low to the north weakens.

It's nearly under an anti-cyclone, but it may be moving northwest into a more unfavorable environment.

[ScottNAtlanta]

This doesn't look like its in a hurry to go anywhere right now. It looked to be moving NW last night, but not much of that now. I'm not sure I'm buying the out to sea just yet, especially if this slow movement continues. Plus, I think the models are more locked on to the eastern feature which I think is going to be ingested into the other one.

[ninel conde]

When was the last time we saw convection maintain like this for a system in the Atlantic basin? Looks well on it's way to becoming a depression and possibly our next named system - Gabrielle.

Stay safe Luis (cycloneye) and all in the Caribbean islands!

its been stuck in the same place for too long. whenever that happens conditions for development usually deteriorate.

[Alyono]

looks like a fairly well defined circ is now forming

[Gustywind]

looks like a fairly well defined circ is now forming

Where do see that circulation Alyono? Thanks.

[Alyono]

near 16N and 65.5W

['CaneFreak]

Agreed. I see an arm of convection developing to the northwest of that area moving into that area. A sign that inflow is improving. Maybe this will develop briefly afterall.

near 16N and 65.5W

[NDG]

I now see the possible LLC near 15.9N & 65.7W
Still appears to be somewhat elongated.
I am fairly confident that the recon will find it to be at least a TD, IMO

[NDG]

Sounds familiar. This is what I wrote last night:

The height gradient from the upper level high in the eastern Caribbean and the upper level low to the north is causing a BUNCH of shear in the path of this disturbance (moving northwest). If you want this thing to develop, you better hope the upper low to the north weakens.

It's nearly under an anti-cyclone, but it may be moving northwest into a more unfavorable environment.

Models continue to show that the ULL to the north of 97L will slowly move eastward and the anticyclone about on top of 97L to move along with it northward, at least in the short term, so by the time 97L gets north of Hispaniola UL conditions will be much better in that area than they are now.

[Alyono]

Agreed. I see an arm of convection developing to the northwest of that area moving into that area. A sign that inflow is improving. Maybe this will develop briefly afterall.

near 16N and 65.5W

conditions will be favorable north of Hispañiola. Much of that shear is due to the anti-cyclone. That should move in tandem with the disturbance

[Hammy]

I'm wondering if the easterward disturbance might keep going west for now and work to pull 97L straight north for about ~12 hours once it passes, and then merge after that.

['CaneFreak]

Oh ok. Thanks guys. I guess I was viewing this through the wrong frame of reference. I think I now see the split now in the upper levels between the UL disturbance over the central Caribbean and the UL disturbance over the central western Atlantic. You may have dual outflow channels going by the time this gets north of Hispaniola. Good thing there is a trough coming off the east coast.

http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor1&zoom=&time=

[Gustywind]

Interrestinf discussion from Dr. Jeff Masters.

Posted by: Dr. Jeff Masters, 15:31 GMT le 04 septembre 2013
Dr. Jeff Masters' WunderBlog

http://www.wunderground.com/blog/JeffMa ... rynum=2511

97L Dumping Heavy Rains on Puerto Rico, Virgin Islands

A tropical wave over the Northeast Caribbean (Invest 97L) is slowly growing more organized as it moves west-northwest at 10 mph towards Puerto Rico and the Dominican Republic. Winds gusts of 36 mph have been recorded this morning at buoy 41052 south of St. John in the Virgin Islands, and heavy thunderstorms from 97L have dumped over an inch of rain in many locations in the Virgin Islands and Northern Puerto Rico as of 11 am AST Wednesday. Puerto Rico doesn't need the rain, as they have had one of their wettest years on record; San Juan is nearly two feet (23.49") above average in rainfall for the year. Satellite loops show that 97L has a moderate amount of spin and heavy thunderstorms, with a respectable upper-level outflow channel to the north.

There is no sign of a well-organized surface circulation. Long-range radar out of San Juan, Puerto Rico shows some modest spin to 97L's echoes, but no well-organized low-level spiral bands. Upper level winds are favorable for development, with wind shear a low 5 - 10 knots. There is some dry air from the Saharan Air Layer (SAL) that is interfering with development, but this is becoming less of an issue as heavy thunderstorms from 97L continue to moisten the storm's environment.

Forecast for 97L
Wind shear is expected to be low through Friday night, and ocean temperatures will be warm, 29°C. One wild card is how 97L will interact with a strong tropical wave about 500 miles to its east, just east of the Lesser Antilles Islands. This new tropical wave may compete for moisture, slowing development of 97L, and could also modify the track of 97L.

The models take 97L to the west-northwest, bringing the center over the eastern tip of the Dominican Republic on Thursday morning. This track will allow the high mountains of Puerto Rico and Hispaniola to disrupt the circulation of 97L, forcing the storm to regroup on Friday over the Southeast Bahamas and Turks and Caicos Islands. The best chance for development of 97L would appear to be on Saturday, after the storm has had time to recover from its encounter with Hispaniola. The UKMET model predicts that 97L will become a tropical depression just north of the Southeast Bahamas and Turks and Caicos Islands on Saturday, but the GFS and European models show little development over the next three days. There will be a strong trough of low pressure off the U.S. East Coast this weekend, and the models predict that this trough will be strong enough to turn 97L to the north and northeast by Sunday, keeping 97L well offshore from the U.S. East Coast, but with a possible threat to Bermuda next week. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC boosted the 5-day odds of formation of 97L to 60%, and 2-day odds to 40%.
The Hurricane Hunters are on call to investigate 97L Wednesday afternoon. The Hurricane and Severe Storm Sentinel Mission, a 5-year field project utilizing two remotely crewed Global Hawk aircraft to overfly tropical storms and hurricanes, will have one of their aircraft investigate 97L today. You can follow the progress of the aircraft using NASA's live-plane tracker map (Global Hawk AV6 is tail number NASA872, and Global Hawk AV1 is tail number NASA871.)

Regardless of whether or not 97L becomes a tropical depression today, the major danger from this slow-moving storm will be heavy rains. Three to six inches of rain are predicted to fall over Puerto Rico and the Virgin Islands by Thursday morning, with 3-day rainfall totals of 5 - 10 inches expected along the south and southeast shores of Puerto Rico. These rains are capable of causing dangerous flash flooding and mudslides, and a Flash Flood Watch has been posted. Similar rainfall amounts will fall in the eastern Dominican Republic, and heavy rains of 3 - 6 " are also likely to affect the Southeast Bahamas and Turks and Caicos Islands later in the week. Since 97L is relatively small, Haiti may see lower rainfall amounts of 2 - 4 inches.

[Zanthe]

I don't think they'll call it a TD very soon. Maybe by the end of the day, but for now, it looks like a developing TD. The system seems to be getting more and more organized -- slowly. With the lack of quality systems this year, though, we want to believe that any blow up could be a TD. That isn't true, and remember how many systems have fallen apart this year.

I still think this system will eventually be a TD, but I don't think it is quite yet.

[Gustywind]

near 16N and 65.5W

Ok thanks for you input

[floridasun78]

hurr hunter going fly today?

[cycloneye]

hurr hunter going fly today?

Yes. Plane departs at 1:00 PM EDT. Go to 97L recon thread

[floridasun78]

hurr hunter going fly today?

Yes. Plane departs at 1:00 PM EDT. Go to 97L recon thread

it say sep 5 on report

[cycloneye]

hurr hunter going fly today?

Yes. Plane departs at 1:00 PM EDT. Go to 97L recon thread

it say sep 5 on report

Here is the mission that will go shortly.

SUSPECT AREA (CARIBBEAN)
FLIGHT ONE -- TEAL 70
A. 04/1800Z
B. AFXXX 01DDA INVEST
C. 04/1700Z
D. 16.8N 65.5W
E. 04/1730Z TO 04/2130Z
F. SFC TO 10,000 FT

[MaineWeatherNut]

I don't think they'll call it a TD very soon. Maybe by the end of the day, but for now, it looks like a developing TD. The system seems to be getting more and more organized -- slowly. With the lack of quality systems this year, though, we want to believe that any blow up could be a TD. That isn't true, and remember how many systems have fallen apart this year.

I still think this system will eventually be a TD, but I don't think it is quite yet.

If they call it a TD today it will be before the end of the day. Recon flies today at 1pm EDT so as soon as they get confirmation of a LLC from Recon then they will upgrade it to a TD or TS depending on what sort of Winds Recon finds.