97L growing more organized, will bring heavy rain to the Lesser Antilles

By: Dr. Jeff Masters , 3:55 PM GMT on July 19, 2009

Share this Blog
1
+

The tropical wave near 12N 52W, about 600 miles east of the Lesser Antilles Islands (97 L), has grown more organized this morning as it tracks west at about 20 mph. This wave is surrounded by an area of very dry air from the Sahara Desert, but 97L has been able to steadily moisten a large region of the atmosphere over the past day, insulating itself from the dry air. This moistening process has been aided by sea surface temperatures (SSTs) that have steadily increased from 26.5°C to 27.5°C, plus the presence of only 10 knots of wind shear. The system now has a small area of intense thunderstorms near its center, with some rotation of the cloud pattern evident at mid-levels of the atmosphere. An upper-level outflow channel has opened to the north, and there is evidence that surface spiral bands are beginning to form. This morning's QuikSCAT pass missed 97L, so we don't know what is happening at the surface.

Wind shear is a modest 10 knots over the disturbance, and is forecast to remain in the moderate 10 - 15 knot range through Monday morning. This should allow further development to occur today, and 97L could be approaching tropical depression strength on Monday as it moves through the central Lesser Antilles Islands. Monday night, shear is expected to rise to 20 - 30 knots, thanks to the presence of a trough of low pressure at upper levels of the atmosphere over the eastern Caribbean. Since 97L is a relatively small system, it is very vulnerable to wind shear. This shear may be able to drive some of the dry air west of 97L deep into its interior, significantly disrupting the disturbance. Shear will remain high along 97L's path through Thursday, when the storm should be in the western Caribbean near Cuba. If there is anything left of 97L by then, some development is possible. The National Hurricane Center gave 97L a low (less than 30% chance) of developing into a tropical depression in the next 48 hours in their 8am Tropical Weather Outlook. However, I'd say the odds are now in the medium range (30 - 50%).

None of the computer models are forecasting tropical storm development over the next seven days.


Figure 1. Current satellite image of African wave 97L.

I'll have an update Monday morning. As 97L approaches the islands, you may want to follow local observations there using our wundermap for 97L.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1665 - 1615

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48Blog Index

Looks like a new burst of convection firing near the center of 97.
Member Since: Posts: Comments:
1664. KEEPEROFTHEGATE (Mod)
Quoting StormW:


Been a while...I think Mother Nature thinks it's October or something.


evening storm

feels like october where iam
Member Since: July 15, 2006 Posts: 170 Comments: 53553
1663. WxLogic
Quoting JRRP:



It has been managing since it has been able to stay away from the SAL up north... as you mentioned it could be interesting if it's able to get ahead of the SAL and gain some latitude.
Member Since: August 14, 2008 Posts: 4 Comments: 4965
1662. Ossqss
Quoting StormW:


Been a while...I think Mother Nature thinks it's October or something.


I am not a Met, but I have been watching a long time (20+ years) and that just looks unusual to me. Worth watching, IMHO.
Member Since: Posts: Comments:
It seems the weather has been all over the place so far this season.

A front in the GOM? A ULL instead of a Twave bringing moisture to S Florida?

Hmmmm.....
Member Since: Posts: Comments:
1660. JRRP
Quoting stormwatcherCI:
I think we need to watch the wave(blob)east of 30 w although it is pretty far south looks pretty healthy.

Member Since: Posts: Comments:
1659. IKE
Quoting StormJunkie:
We have 134 to go and.....it's over.
27% of the season is behind us.


Ike, please don't mock The Season™...It will last til January just to spite you...lol


LOL....

My prediction was no named storm through July. I still may be right.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting barbadosjulie:
Should Barbados get any rain out of this?


Of course we will, but now sure how much yet (maybe an inch or even less)

have to wait till morning...
Member Since: Posts: Comments:
1656. JRRP
Quoting BurnedAfterPosting:
97L still has good rotation, it lost some convection, some is starting to build already, it is a long way away from DMAX, if it can keep building it might be able to survive

structure of the system still looks good, just an hour ago the NHC said it "continued to get better organized", so lets go with that for now.

at least the rotation is there
Member Since: Posts: Comments:
We have 134 to go and.....it's over.
27% of the season is behind us.


Ike, please don't mock The Season™...It will last til January just to spite you...lol
Member Since: Posts: Comments:
Quoting Barbados:
Come on 97L. At least bring us something to cool us down.


tomorrow will be very interesting...
Member Since: Posts: Comments:
1652. IKE
Quoting Ossqss:
StormW, when was the last time you saw a sat with the hard turn over the GoM like this ?

It looks impressive now, and I really don't remember a time as such.



You see it a few times in the winter. I'm in the panhandle of Florida. Just got a beneficial quarter inch of rain.

Who needs 97L?

For the record....

We are through 49 days of the tropical season.
We have 134 to go and.....it's over.
27% of the season is behind us.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Should Barbados get any rain out of this?
Member Since: Posts: Comments:
1650. WxLogic
Hi Pot...
Member Since: August 14, 2008 Posts: 4 Comments: 4965
Pretty weak, but well defined...



Microwave pass that is under 2 hours old.
Member Since: Posts: Comments:
1647. pottery
Greetings.
No rains for me today in central Trinidad, but some heavy showers, for long periods, along the north of the island, and heavy rains in Tobago, Grenada, St.Vincent.
The system looks pretty unhealthy now, at d-min, will it pull itself back together tonight?
I have my doubts, now.
Member Since: Posts: Comments:
1646. WxLogic
Quoting IKE:


Yes.

BREAKING NEWS: It's raining at my house as cloud tops are cooling.

Rain and 76.3 outside my window as I type.


lol!!!
Member Since: August 14, 2008 Posts: 4 Comments: 4965
1645. Ossqss
StormW, when was the last time you saw a sat with the hard turn over the GoM like this ?

It looks impressive now, and I really don't remember a time as such.

Member Since: Posts: Comments:
New CIMSS maps in 21 minutes
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Ode to 97L?
Member Since: Posts: Comments:
Evening BAP...

I agree, the structure is much improved over yesterday and it did manage to keep at least some convection for most of the day. All up to the night time cooling now.Also looks like it might be starting to feel the shear a little more.
Member Since: Posts: Comments:
1641. surfmom
Quoting Barbados:
Come on 97L. At least bring us something to cool us down.


perhaps some ground swell - I like
'dem TS's not 'canes ..but a little TS would make me happy
Member Since: Posts: Comments:
Quoting StormJunkie:
Thanks alania! He is a blast :~) He is 7.5 months and just started saying umamma and igda (daddy) I think...lol


LOL! I miss Julian being that small. Well at least your son is attempting daddy. Julian calls his daddy by his name! LOL. Something he picked up on his own from hearing everyone call him by his name instead of daddy.
Member Since: Posts: Comments:
1639. IKE
Quoting CaneWarning:
Could we be witnessing RIP #2?


Yes.

BREAKING NEWS: It's raining at my house as cloud tops are cooling.

Rain and 76.3 outside my window as I type.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1638. surfmom
Quoting Sockets:
I see 97l has felt the wrath of Bill Gates
Mr. Gates needs to keep his hands on his Motherboard --not Mother Nature . 'cause she'll spit him and the rest of us out out in heartbeat --should she be in the mood
Member Since: Posts: Comments:
Quoting StormJunkie:
Thanks alania! He is a blast :~) He is 7.5 months and just started saying umamma and igda (daddy) I think...lol


Your son is adorable, SJ. :)
Member Since: Posts: Comments:
Quoting CaneWarning:
Could we be witnessing RIP #2?


Yep and than "omg its a td" tomorrow morning

Member Since: Posts: Comments:
Come on 97L. At least bring us something to cool us down.
Member Since: Posts: Comments:
Quoting StormW:


1544. StormW 8:21 PM EDT on July 19, 2009
Quoting Nolehead:
StormW

what's your feel on the convection in the GOM...

Looks like the energy that's supposed to be left behind when the trof split occurs. The upper level environment is forecast at the moment not to be that conducive over the GOMEX.



I should have known you would notice it before me, Storm. :P
Member Since: Posts: Comments:
Thanks alania! He is a blast :~) He is 7.5 months and just started saying umamma and igda (daddy) I think...lol
Member Since: Posts: Comments:
Quoting StormW:


1544. StormW 8:21 PM EDT on July 19, 2009
Quoting Nolehead:
StormW

what's your feel on the convection in the GOM...

Looks like the energy that's supposed to be left behind when the trof split occurs. The upper level environment is forecast at the moment not to be that conducive over the GOMEX.



Thanks Storm, I missed this post.
Member Since: Posts: Comments:
97L still has good rotation, it lost some convection, some is starting to build already, it is a long way away from DMAX, if it can keep building it might be able to survive

structure of the system still looks good, just an hour ago the NHC said it "continued to get better organized", so lets go with that for now.
I think we need to watch the wave(blob)east of 30 w although it is pretty far south looks pretty healthy.
Member Since: October 9, 2008 Posts: 0 Comments: 8333
Quoting StormJunkie:
Evening all

Ike, I agree...Looks pretty ragged right now and it won't survive shear looking like that. It is going to have to really take advantage of diurnal cooling if it is going to make it through any significant shear.


I have been wanting to say how adorable I think your son is. I have a 2 year old son as well. Arent they just so much fun? (and work lol)
Member Since: Posts: Comments:
1627. KEEPEROFTHEGATE (Mod)


latest 901 pm edt wv image enhanced
Member Since: July 15, 2006 Posts: 170 Comments: 53553
Could we be witnessing RIP #2?
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting STORMMASTERG:
Link 18Z WRF SHEAR.


Please enough with the wrf model
Member Since: Posts: Comments:
Evening all

Ike, I agree...Looks pretty ragged right now and it won't survive shear looking like that. It is going to have to really take advantage of diurnal cooling if it is going to make it through any significant shear.
Member Since: Posts: Comments:
1623. Sockets
I see 97l has felt the wrath of Bill Gates
Member Since: Posts: Comments:
Quoting Ossqss:


You did not get banned for fighting, LoL

No kidding, there is a huge amount of talent here and it should not be stifled by disagreement.

Just my take.

I agree...and also your own input this year has been a good addition.
.
.
Member Since: Posts: Comments:
Quoting KoritheMan:
I'm surprised no one has mentioned the northern Gulf of Mexico trough yet. Upper winds may be marginally favorable for slow development over the next few days. But in case anyone is wondering, it is not going to remain in the Gulf for very long, as the steering flow will carry it eastward across the Florida peninsula and into the western Atlantic over the next few days.

This is also climatologically possible, and Edouard last year formed from a similar situation at a similar time of year.


I been watching it!
Member Since: Posts: Comments:
1620. Mikla
Member Since: Posts: Comments:
1619. Ossqss
Quoting CosmicEvents:

What....no love for those who provide common sense input? There's plenty of room for both.


You did not get banned for fighting, LoL

No kidding, there is a huge amount of talent here and it should not be stifled by disagreement.

Just my take.


Edit, I asked about the sloppy trough earlier in the GOM. Looks familiar to me.
Member Since: Posts: Comments:
I'm surprised no one has mentioned the northern Gulf of Mexico trough yet. Upper winds may be marginally favorable for slow development over the next few days. But in case anyone is wondering, it is not going to remain in the Gulf for very long, as the steering flow will carry it eastward across the Florida peninsula and into the western Atlantic over the next few days.

This is also climatologically possible, and Edouard last year formed from a similar situation at a similar time of year.
Member Since: Posts: Comments:
1617. IKE
Ain't much left, right now...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Bay News 9 has their own model and they show "tropical moisture" going through the Bahamas and off the east coast of Florida.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Link 18Z WRF SHEAR.
Member Since: Posts: Comments:

Viewing: 1665 - 1615

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Overcast
75 °F
Overcast