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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Quoting hydrus:
Good morning old dude..Geritol this mornin....?..:)


LOL...don't need it...

Now the blog, on the other hand
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Good morning, please check out my 9AM CDT blog update on the NC Flooding/97L updates and please leave your comments.

I will be writing a daily news article, starting this week for "The Arlington (TX) Weather Examiner" and this is the article formats I will use, thanks:
Link
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Quoting pottery (#37):
I am interested in the Mechanics of the thing...


Maybe it's part of a massive experiment! :-)
Member Since: November 8, 2009 Posts: 4 Comments: 13568
The chances of anything hitting the US moving N of Puerto Rico from here on out are slim to none. Although it has happened on a rare occasion.
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For those of you that follow my site.. I now have a domain name that has been posted at my blog
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Quoting dayton:
I take it that the U.S. coast is out of the woods for a direct hurricane hit the rest of the season?

I'm not sure why all the forecasters were wrong this year, but it looks like we dodge a major bullet from what was forecasted.



I wouldn't make that comment yet being only the 4th of October. October is the Caribbean's playground and with the pattern set up bringing regular troughs down, most likely would be pulled up and out. Most likely track is across the SE.



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Tropical Update Oct. 4th. 2010
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Invest97L : NHC-ATCF
3Oct 12pmGMT - - 17.6n60.1w - - 25knots -- 1007mb -- NHC-ATCF *17.7n59.8w
3Oct 06pmGMT - - 17.6n61.4w - - 25knots -- 1007mb -- NHC-ATCF *17.8n61.8w
4Oct 12amGMT - - 17.6n62.8w - - 25knots -- 1007mb -- NHC-ATCF *17.8n63.9w
4Oct 06amGMT - - 17.6n64.1w - - 25knots -- 1007mb -- NHC-ATCF *17.8n65.4w
4Oct 12pmGMT - - 17.7n65.4w - - 25knots -- 1007mb -- NHC-ATCF
* Coordinates from 6hours ago, before NHC reevaluated&altered the ATCF numbers

Copy&paste 17.6n60.1w-17.6n61.4w, 17.6n61.4w-17.6n62.8w, 17.6n62.8w-17.6n64.1w, 17.6n64.1w-17.7n65.4w, cbj, pop, fdf into the GreatCircleMapper for a look at the last 24*hours.
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Quoting Floodman:
Hmmm...apparently most folks have decided that the serason IS over...LOL

The blog is certainly dead this morning
Good morning old dude..Geritol this mornin....?..:)
Member Since: September 27, 2007 Posts: 1 Comments: 21432
97 is in the takes 3 weeks to form zone
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Quoting Neapolitan:
But it has been an "unusually active" season, and there's a lot of it left.

A) 2010 has already had more tropical cyclones than six of the previous 15 seasons, all of which, of course, are included in the "current active hurricane era". Just two more named systems--which I'll bet my life on happening--will put 2010 ahead of all but three of those previous 15.

B) It's sort of a misstatement to call GOM SSTs "marginal" at 26.C-28.C. Except for a few very tiny areas, the entire GOM is still capable of generating and sustaining tropical cyclone activity. No, the temps aren't August hot...but they're plenty warm.

No professional forecaster is going to tell anyone that the season is over. In 1991, tropical activity seemed over as of September 12 with the demise of TS Erika. It hadn't been a busy year: two hurricanes and a small handful of tropical storms. And September rolled into October and cold fronts started sweeping southward as they always do, causing people to no doubt proclaim the 1991 Atlantic Hurricane Season as officially over.

But then...

On October 15th, what would become TS Fabian formed in the Gulf of Honduras. On the 24th, TD 10 popped up in the Atlantic. On the 26th--just two days later--Hurricane Grace, which would become a Cat 2 storm--formed in the cold waters just south of Bermuda. Two days after that, the Cat 1 1991 Unnamed Hurricane formed in even colder waters farther north. This storm was an extratropical system that moved south over the Gulf Stream, where it took on tropical characteristics (though the NHC didn't name it "Henri" to avoid scaring the public).

The big deal about that is, of course, that Grace's remains mixed with "Henri's" and a strong cold front to become the deadly and devastating "Perfect Storm".

I'll repeat--until I'm blue in the face, or at least until December 1st, whichever comes first--the 2010 hurricane season isn't over. :-)
I believe there are quite a few storms in our future..The water temperatures are still warmer than normal in most parts of the Atlantic. I am betting November will be an eventful month...Just my harmless opinion..:)
Member Since: September 27, 2007 Posts: 1 Comments: 21432
0945 AM EDT MON 04 OCTOBER 2010
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 05/1100Z TO 06/1100Z OCTOBER 2010
TCPOD NUMBER.....10-125

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK: POSSIBLE LOW LEVEL INVEST AT 06/1800Z NEAR 21N 69W.
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Quoting txag91met:
35F in East Texas this morning...

Link And it looks legit.


mid 50s in west Houston this morning , and we could conceivably hit the upper 40s the next couple of mornings.

The house geckos and the frogs that hang around the front porch aren't liking it. Haven't really seen the frogs much in the last week, and didn't see any of the geckos this morning.
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Hmmm...apparently most folks have decided that the serason IS over...LOL

The blog is certainly dead this morning
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Quoting dayton:
I take it that the U.S. coast is out of the woods for a direct hurricane hit the rest of the season?

I'm not sure why all the forecasters were wrong this year, but it looks like we dodge a major bullet from what was forecasted.


You take it wrong...the CONUS is nearly always at risk; the reasons for not being hit are generally environmental and episodic
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But it has been an "unusually active" season, and there's a lot of it left.

A) 2010 has already had more tropical cyclones than six of the previous 15 seasons, all of which, of course, are included in the "current active hurricane era". Just two more named systems--which I'll bet my life on happening--will put 2010 ahead of all but three of those previous 15.

B) It's sort of a misstatement to call GOM SSTs "marginal" at 26.C-28.C. Except for a few very tiny areas, the entire GOM is still capable of generating and sustaining tropical cyclone activity. No, the temps aren't August hot...but they're plenty warm.

No professional forecaster is going to tell anyone that the season is over. In 1991, tropical activity seemed over as of September 12 with the demise of TS Erika. It hadn't been a busy year: two hurricanes and a small handful of tropical storms. And September rolled into October and cold fronts started sweeping southward as they always do, causing people to no doubt proclaim the 1991 Atlantic Hurricane Season as officially over.

But then...

On October 15th, what would become TS Fabian formed in the Gulf of Honduras. On the 24th, TD 10 popped up in the Atlantic. On the 26th--just two days later--Hurricane Grace, which would become a Cat 2 storm--formed in the cold waters just south of Bermuda. Two days after that, the Cat 1 1991 Unnamed Hurricane formed in even colder waters farther north. This storm was an extratropical system that moved south over the Gulf Stream, where it took on tropical characteristics (though the NHC didn't name it "Henri" to avoid scaring the public).

The big deal about that is, of course, that Grace's remains mixed with "Henri's" and a strong cold front to become the deadly and devastating "Perfect Storm".

I'll repeat--until I'm blue in the face, or at least until December 1st, whichever comes first--the 2010 hurricane season isn't over. :-)
Member Since: November 8, 2009 Posts: 4 Comments: 13568
Quoting pottery:

Well, I have not gone out on a limb. Yet!
But I am cautiously setting the stage, for a succinct remark pertaining to the imminent demise of the 2010 season.
Of course, as you know, timing is everything in these important matters.


Yup.. your going to need it
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Thanks Dr. Masters for the update.
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Back in a few...
the 'sweepers and moppers' require my removal so that they can perform....
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Quoting Orcasystems:


Oh oh... what did you do?

Well, I have not gone out on a limb. Yet!
But I am cautiously setting the stage, for a succinct remark pertaining to the imminent demise of the 2010 season.
Of course, as you know, timing is everything in these important matters.
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35F in East Texas this morning...

Link And it looks legit.
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Quoting pottery:
Hi Orca!
I may need to refer to your 'busted forecast alibi' soon...


Oh oh... what did you do?
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Hi Orca!
I may need to refer to your 'busted forecast alibi' soon...
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WV
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Complete Update


AOI
AOI AOI AOI

AOI AOI AOI

TS BUSTED FORECAST ALIBI
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Quoting Neapolitan:


First part: absolutely untrue. See the image below, which shows all post-September hurricanes and tropical storms in the GOM over the past 150 years.

Second part: because of the first part, it's far too early to say, "...all the forecasters were wrong this year" If Nicole was the season's last, then go ahead and restate that on December 1 and I'll try to explain...


I understand the points you are making.
But conditions are now changing, and as it stands now, SST are marginal in the GOM for development of a major storm (I am NOT saying that we could not see a system bring bad news due to rains ect)
And I am not saying that the season has not been "active".
I am saying that the forecasts for an UNUSUALLY active season have not verified.
I am interested in the Mechanics of the thing...
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Quoting dayton (#22):
I take it that the U.S. coast is out of the woods for a direct hurricane hit the rest of the season?

I'm not sure why all the forecasters were wrong this year, but it looks like we dodge a major bullet from what was forecasted.


First part: absolutely untrue. See the image below, which shows all post-September hurricanes and tropical storms in the GOM over the past 150 years.

Second part: because of the first part, it's far too early to say, "...all the forecasters were wrong this year" If Nicole was the season's last, then go ahead and restate that on December 1 and I'll try to explain...

Post-September tropical cyclones in the GOM over the past 15 decades (click for larger image):

Appropriate tropical weather-related image


Member Since: November 8, 2009 Posts: 4 Comments: 13568
Invest97L : NHC-ATCF
3Oct 06amGMT - - 17.6n58.7w - - 25knots -- 1007mb -- NHC-ATCF *17.5n58.4w
3Oct 12pmGMT - - 17.6n60.1w - - 25knots -- 1007mb -- NHC-ATCF *17.7n59.8w
3Oct 06pmGMT - - 17.6n61.4w - - 25knots -- 1007mb -- NHC-ATCF *17.8n61.8w
4Oct 12amGMT - - 17.6n62.8w - - 25knots -- 1007mb -- NHC-ATCF *17.8n63.9w
4Oct 06amGMT - - 17.6n64.1w - - 25knots -- 1007mb -- NHC-ATCF *17.8n65.4w
* Coordinates 6hours ago, before NHC reevaluated&altered the ATCF numbers
New numbers already well overdue past their normal 45minutes after the reporting-hour

Copy&paste 17.6n58.7w-17.6n60.1w, 17.6n60.1w-17.6n61.4w, 17.6n61.4w-17.6n62.8w, 17.6n62.8w-17.6n64.1w, azs, uvf into the GreatCircleMapper for a look at the last 24*hours.
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Quoting PensacolaDoug:



Over and over again. It seems like we have to keep relearning the same things. Long-range forecasting is little more than a crap-shoot beyond a week.

Apparently, LOL!
But all the known and assumed conditions were seemingly perfect for an unusual season.
Were the conditions "too perfect?"
Did the record heat (SST and Land) tend to create a 'damping' effect?
Or what???
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Quoting JRRP:
see you later

Walk with your umbrella.....
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Quoting pottery:

It will be very interesting to see some analysis of this season, after it is all over.
The season did not live up to the expectations of major storms in record numbers.
Why is that?



Over and over again. It seems like we have to keep relearning the same things. Long-range forecasting is little more than a crap-shoot beyond a week.
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Post 24.
West winds and pressure of 1002.6 in Barbados.
Interesting
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28. JRRP
see you later
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56 degrees on my porch here in N. Texas, I hardly know what to do with myself.
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Quoting dayton:
I take it that the U.S. coast is out of the woods for a direct hurricane hit the rest of the season?

I'm not sure why all the forecasters were wrong this year, but it looks like we dodge a major bullet from what was forecasted.

It will be very interesting to see some analysis of this season, after it is all over.
The season did not live up to the expectations of major storms in record numbers.
Why is that?
Member Since: Posts: Comments:
24. JRRP

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I take it that the U.S. coast is out of the woods for a direct hurricane hit the rest of the season?

I'm not sure why all the forecasters were wrong this year, but it looks like we dodge a major bullet from what was forecasted.
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Good Morning everyone. Well it certainly feels like fall in the keys with a north wind blowing and cloud cover. WONDERFUL!!! I am hoping it will stay this way, but really don't think it will. Way too early.
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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.