97L still disorganized, but bringing heavy rains to the northeast Caribbean

By: Dr. Jeff Masters , 12:27 PM GMT on October 04, 2010

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A large region of disturbed weather (Invest 97L) covers the Lesser Antilles Islands and waters near Puerto Rico and the Virgin Islands. The storm is headed west-northwest at about 10 mph, and will bring heavy rain showers and gusty winds to the Lesser Antilles, Puerto Rico, the Virgin Islands, and the Dominican Republic today. These showers can be seen on Martinique radar this morning, and Martinique reported a wind gust of 35 mph this morning during one of 97L's heavy squalls. An upper level trough of low pressure is contributing to the heavy rain showers by making the atmosphere more unstable. This same trough is also bringing moderate wind shear of 10 - 20 knots, which will keep any development today very slow to occur. Recent satellite imagery shows a large area of intense thunderstorms associated with 97L, but the activity is not well organized, and there are no signs of a surface circulation. Long range radar out of Puerto Rico also shows no signs of rotation.


Figure 1. Morning satellite image of Invest 97L.

Forecast for 97L
The SHIPS model predicts that wind shear over 97L will slowly fall over the next three days, reaching the low range, 5 - 10 knots, by Thursday, which may allow the storm to develop into a tropical depression, if its center can stay over water. All of the major computer models now show development of 97L into a tropical depression Wednesday or Thursday, just north of Hispaniola. By Thursday, a passing trough of low pressure is expected to pull 97L to the northeast away from Hispaniola, and rains should end by Friday on the island if this forecast verifies. NHC is giving 97L a 20% chance of developing into a tropical depression by Wednesday. 97L will move at about 5 - 10 mph today through Wednesday, bringing the potential for an extended 3-day period of heavy rains for the islands in its path. These rains may result in life-threatening flash flooding and mudslides in Puerto Rico and the Dominican Republic today through Wednesday, and for Haiti Tuesday through Thursday. Flash flood watches are posted for the Virgin Islands and Puerto Rico today.

Elsewhere in the tropics
An area of disturbed weather near 10N, 47W is under a high 20 knots of wind shear, and is headed northwest into a region of even higher wind shear of 20 - 30 knots. Satellite imagery shows only a limited amount of heavy thunderstorms, and there is plenty of dry air in the vicinity that is interfering with development. NHC is giving the disturbance a 10% chance of developing into a tropical depression by Wednesday.

Most of the models indicate the possibility that a strong tropical disturbance capable of becoming a tropical depression will form in the Central or Southern Caribbean 6 - 8 days from now.

Next update
I'll have an update Tuesday morning.

Jeff Masters

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In late May, NOAA predicted an "extremely active" season ranging from a low of 14-8-3 to a high of 23-14-7. In August they revised downward to between 14-8-4 and 20-12-6.

Meanwhile, Klotzbach & Gray at CSU originally called for between 11-6-3 to 16-8-5; that was revised in June to 18-10-5.

In mid-June, the UK Met Office called for 20 storms, with a 70% chance of between 13 and 27, and a 70% chance of an ACE index between 90 to (a ludicrously high) 319.

So: we're at, obviously, 14-7-5, with an ACE of 131. That means we've reached the low end of the NOAA forecast for named storms, we're just one hurricane away from reaching their low end prediction for hurricanes, and we've almost doubled the minimum number of intense hurricanes they called for. It also means we've reached the low end of the CSU forecasts for named storms and hurricanes, and we've reached their predicted number of major storms. And, finally, it also means we've exceeded the low end of the UK Met prediction for both storms and ACE.

Ther bottom line: we're here at the start of October having already fallen in line with at least the low end of most of the pre-season predictions, despite the late start to anything more than minimal activity. There are nearly two months left in the regular season, there are still very-high SSTs across most of the MDR, and there are currently two AOIs, one looking healthier and healthier.

And yet I keep reading over and over here how the pre-season forecasts were wrong. How so? I never saw anyone reputable claim 2010 would be the Mother Of All Seasons (that title will likely long belong to 2005); I merely saw predictions of a very active to hyperactive season. Well, we're already at very active, and there's plenty of time left to reach hyperactive. Doing a post-mortem at this point seems about eight weeks premature...
Member Since: Posts: Comments:
Quoting cat5hurricane:
Gulf coast sure lucked out.

Well, luck is sometimes needed in this Life.
But in terms of tropical storms, there is more to it than that.
Something caused the thing.....
Member Since: October 24, 2005 Posts: 0 Comments: 24881
568. JLPR2
Looking more and more interesting and arrg! And got to be sleeping before 2am :(

Member Since: September 4, 2007 Posts: 7 Comments: 8747
567. Relix
Wouldn't surprise me to see a TCFA tomorrow at morning or midday.
Member Since: Posts: Comments:
Quoting Orcasystems:


Especially when his blog points you right to another website and separate blog... he catches on quick.


AH!
Member Since: October 24, 2005 Posts: 0 Comments: 24881
Quoting pottery:

Very quick...


Especially when his blog points you right to another website and separate blog... he catches on quick.

Member Since: Posts: Comments:
Quoting Gearsts:
Invest 97
Wind: 30 MPH — Location: 17.5 64.5W — Movement: WSW
This area of disturbed weather has the potential for tropical development.Moving wsw?

Where did you see WSW?
Member Since: October 24, 2005 Posts: 0 Comments: 24881
Quoting Orcasystems:


Since you have been a member for almost a whole day now.. I doubt I have seen it.

Very quick...
Member Since: October 24, 2005 Posts: 0 Comments: 24881
Invest 97
Wind: 30 MPH — Location: 17.5 64.5W — Movement: WSW
This area of disturbed weather has the potential for tropical development.Moving wsw?
Member Since: Posts: Comments:
558. JLPR2
Quoting kmanislander:
I'm out for tonight as well. May be back tomorrow, depending on what happeans with 97L and the other area to the South of the DR.

Gnite all.
Quoting Patrap:



G'night chicklit..Im heading up too.
Quoting HurricaneDean07:
Im getting off,
Good night all
I'll have a new blog post in the morning


Night!
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Hard to beleive no gulf coast strikes this year
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Quoting Orcasystems:


Since you have been a member for almost a whole day now.. I doubt I have seen it.

Actually i've been following since 2008 but, I just joined.
Member Since: Posts: Comments:
I'm out for tonight as well. May be back tomorrow, depending on what happeans with 97L and the other area to the South of the DR.

Gnite all.
Member Since: Posts: Comments:
Quoting Chicklit:
Cool patrap. my sound doesn't work since i rearranged my office. don't know why i cannot figure out this, but just hasn't happened yet.
anyway gn.



G'night chicklit..Im heading up too.
Member Since: July 3, 2005 Posts: 428 Comments: 129841
Im getting off,
Good night all
I'll have a new blog post in the morning
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Conditions are changing: Where is the shear we had this morning around 22N, 45W??? It's gone.... No shear for blob behind 97L....
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Quoting HurricaneDean07:

D.O.O.M.
If you check my blog i'm expecting at least another 3 storms


Since you have been a member for almost a whole day now.. I doubt I have seen it.
Member Since: Posts: Comments:
Quoting kmanislander:


If you look at the tracks this season, the vast majority of storms recurved well East of the CONUS. The reason for this is clearly associated with the strong La Nina that developed and the train of troughs that paraded off the East coast one after the other.
Historically, neutral years see more storms track due West. La Nina see more storms recurve.

As for the lower numbers, well it is largely attributed to dry air and shear. The shear forced dry into many fledgling systems disrupting them in the formative stages and preventing several from developing. Those that did took forever to do so.

Consequently, I would summarise this season as being known for three key elements that prevented it from being the " mother of all seasons ".

1. La Nina
2. Dry air
3 Shear

One final note. Why the dry air ??

Remember the jet stream that got locked into the flow pattern that created the fires and record heat in Russia ?. It also created record heat across the CONUS.

That heat inland on the continents created very dry sinking air ( subsidence ) across the Atlantic which in turn suppressed the development of tropical systems. I think that the post season analysis will focus on this as a key element that was not foreseen.

Many Thanks...
I have been trying to get to the bottom of this for a while.
You are the first to give it the attention it needs, as far as I can see.
Although Masters did a blog some time ago (during the Russia heatwave) that alluded to it, the overall conditions tended to confound the more localised ones.
Most interesting, and brings into sharp focus the relationship between Climate and Weather, in my op.
Nice...
Member Since: October 24, 2005 Posts: 0 Comments: 24881
549. JLPR2
Quoting Relix:
97L rains are in bands, center south of St. Croix... falling pressures... organizing convection.. hmm... HMMMM.....


yeah, but once again I'll bite my tongue unless something impressive shows up on radar.

----------------
Rather large 850mb vort
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Quoting Orcasystems:


I am not to worried about 97L... I am a little concerned about the two following it... someone one this blog.. who is notorious for starting invests over his house... is going to do a double whammy.

He is going to call the season over... and open a new Bottle... can you spell doom?

D.O.O.M.
If you check my blog i'm expecting at least another 3 storms
Member Since: Posts: Comments:
546. Relix
97L rains are in bands, center south of St. Croix... falling pressures... organizing convection.. hmm... HMMMM.....
Member Since: Posts: Comments:
Cool patrap. my sound doesn't work since i rearranged my office. don't know why i cannot figure out this, but just hasn't happened yet.
anyway gn.
Member Since: Posts: Comments:
Quoting Chicklit:

Yeah, that's just how we roll...


U betcha my Lady.

Were screening a few more to Help as StormJunkie did a fine Job re conning for us up there over 2 Days.


SJ's portlight coverage of N. Carolina Gov. Perdue press Conference in the Flooded area.



Member Since: July 3, 2005 Posts: 428 Comments: 129841
Quoting pottery:

I am not seeing any removed comments....
?????


Go back a page P. I've refreshed several times. Hope I'm wrong.
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Quoting Patrap:


Thanx chicklit,,shes a fine woman and were gonna help her get her Chair Back and a lot more.

Yeah, that's just how we roll...
Member Since: Posts: Comments:
good grief. tomorrow is another herculean day.
prayers that you get all the rain and sunshine you want...and not any more than you need!
goodnight.
RE: KMAN:
One final note. Why the dry air ??

Remember the jet stream that got locked into the flow pattern that created the fires and record heat in Russia ?. It also created record heat across the CONUS.

That heat inland on the continents created very dry sinking air ( subsidence ) across the Atlantic which in turn suppressed the development of tropical systems. I think that the post season analysis will focus on this as a key element that was not foreseen.


good point.
Member Since: Posts: Comments:
Finally!! Here it comes.... keep on moving....

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Quoting PSLFLCaneVet:



Grothar, I'll have to go with an Ahh. Comments removed seem a bit over the top. Guess I'll retreat. There's a new sheriff in town, and his name, is Reggie Hammond. Have a nice night all. Can't say hello to friends? Whatever. Admin: ???

I am not seeing any removed comments....
?????
Member Since: October 24, 2005 Posts: 0 Comments: 24881
Quoting pottery:

I was one of the 'bandies' LOL.
What, (in spite of the many favourable conditions) do you think caused the lower than forecast numbers?
And the lack of CONUS hits?

I dont mean "dry air" or "shear"..

What were the conditions that were NOT taken into consideration, that resulted in the lower numbers?

Any ideas?


If you look at the tracks this season, the vast majority of storms recurved well East of the CONUS. The reason for this is clearly associated with the strong La Nina that developed and the train of troughs that paraded off the East coast one after the other.
Historically, neutral years see more storms track due West. La Nina see more storms recurve.

As for the lower numbers, well it is largely attributed to dry air and shear. The shear forced dry into many fledgling systems disrupting them in the formative stages and preventing several from developing. Those that did took forever to do so.

Consequently, I would summarise this season as being known for three key elements that prevented it from being the " mother of all seasons ".

1. La Nina
2. Dry air
3 Shear

One final note. Why the dry air ??

Remember the jet stream that got locked into the flow pattern that created the fires and record heat in Russia ?. It also created record heat across the CONUS.

That heat inland on the continents created very dry sinking air ( subsidence ) across the Atlantic which in turn suppressed the development of tropical systems. I think that the post season analysis will focus on this as a key element that was not foreseen.
Member Since: Posts: Comments:
Quoting Chicklit:
Hi Patrick,
Okay, you got me.
Will do this in the a.m.
Thanks,
J


Thanx chicklit,,shes a fine woman and were gonna help her get her Chair Back and a lot more.
Member Since: July 3, 2005 Posts: 428 Comments: 129841
Quoting Grothar:
Is this an OOHH or an AHHHH?




Grothar, I'll have to go with an Ahh. Comments removed seem a bit over the top. Guess I'll retreat. There's a new sheriff in town, and his name, is Reggie Hammond. Have a nice night all. Can't say hello to friends? Whatever. Admin: ???
Member Since: Posts: Comments:
St. Marteen Radar

Link
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Quoting Krycek1984:


Interesting that with so much warm water nothing of real consequence has developed in the Caribbean. Of course, warm water isn't the only ingredient, but still...

That's why Kman says 'season closed' at 14 lol.
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Quoting Krycek1984:


Interesting that with so much warm water nothing of real consequence has developed in the Caribbean. Of course, warm water isn't the only ingredient, but still...

My point all day.....
What's up with that????
Member Since: October 24, 2005 Posts: 0 Comments: 24881
Hi Patrick,
Okay, you got me.
Will do this in the a.m.
Thanks,
J
Member Since: Posts: Comments:
Quoting Orcasystems:


I am not to worried about 97L... I am a little concerned about the two following it... someone one this blog.. who is notorious for starting invests over his house... is going to do a double whammy.

He is going to call the season over... and open a new Bottle... can you spell doom?

heheheh
Member Since: October 24, 2005 Posts: 0 Comments: 24881
Quoting Chicklit:
The Caribbean has been a pressure cooker all season. If you get out unscathed this year, then you will be extremely lucky.


Interesting that with so much warm water nothing of real consequence has developed in the Caribbean. Of course, warm water isn't the only ingredient, but still...
Member Since: Posts: Comments:
As StormJunkie and portlight assessed the situation in N. Carolina,,,we came across this elderly woman who can use a hand from us.

Presslord just got off the phone with this kind soul and she was in tears over hearing were gonna help her.

So I ask everyone to consider helping us help her.

We can change Lives for the better,,and thats what were gonna do here.

Cuz we can.


Dayle White is a widow from Jacksonville, NC, who lost about 60% of her belongings and her landlord is unsure when or if she'll be able to return to her home. Her renters' insurance (Nationwide) is denying her coverage due to lack of flood coverage. She is on a limited fixed income. She is in need of a place to live...as well as clothes and furniture. We want to help her get another apartment, as well as some clothing and furniture. She is particularly upset over the loss of her recliner chair, which was destroyed.

Please help as you can. And know that Ms. White will be grateful.

We are identifying others in need and will post their stories as things come into focus.


portlight.org


Member Since: July 3, 2005 Posts: 428 Comments: 129841
Quoting Orcasystems:


Ahhh would require depends?

Depends....
Member Since: October 24, 2005 Posts: 0 Comments: 24881
524. JLPR2


I like fast updating images. :]
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Quoting HurricaneDean07:
Thanks Orca, can't believe models are calling for a hurricane out of 97L now. I still put this at the most a strong 65 Mph tropical storm.


I am not to worried about 97L... I am a little concerned about the two following it... someone one this blog.. who is notorious for starting invests over his house... is going to do a double whammy.

He is going to call the season over... and open a new Bottle... can you spell doom?
Member Since: Posts: Comments:
Pass Go, do not collect $200.00

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Thanks Orca, can't believe models are calling for a hurricane out of 97L now. I still put this at the most a strong 65 Mph tropical storm.
Member Since: Posts: Comments:

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

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