Surprise tropical storm forms near the Azores; Invest 91L has potential to develop

By: Dr. Jeff Masters , 5. lokakuuta 2009 klo 14:19 (GMT)

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Surprise! A 70-mph tropical storm popped up seemingly out of nowhere early this morning, in a region of the Atlantic not ordinarily prone to tropical storm formation. Tropical Storm Grace formed at 41.2° north latitude, in a remote ocean area near the Azores Islands. This is the farthest northeast an Atlantic tropical storm has ever formed since satellite observations began in the 1960s. Since 1960, only one tropical storm has formed farther north--Tropical Storm Alberto of 1988, which formed at 41.5°N, off the coast of Cape Cod, Massachusetts. Satellite imagery revealed that Grace formed an eyewall and well-defined eye this morning, though the storm's tropical storm-force winds did not extend out very far from the center. Last night, the center of Grace passed about 20 miles west of Ponta Delgada in the eastern Azores, which recorded sustained winds of 31 mph, gusting to 44 mph. Grace formed over chilly waters of about 23°C, well below the usual threshold of 26°C required for tropical storm formation. Grace's formation was aided by some very cold temperatures in the upper atmosphere (-54°C at 200 mb), which made the atmosphere more unstable than usual. The storm won't be around much longer, as Grace is already over much colder waters of 21°C, and is headed towards even colder waters.


Figure 1. The storm that would later become Tropical Storm Grace passes through the Azores Islands at 14:20 UTC 10/04/09. Image credit: NOAA/CIRA.

Invest 91
A large tropical wave near 12N 46W, about 1000 miles east of the Lesser Antilles Islands, is generating a considerable amount of heavy thunderstorm activity as it moves west-northwest at 15 mph. The wave is under low wind shear, 5 - 10 knots, and is over warm waters, 29°C, which is 3°C above the threshold typically needed to allow tropical storm formation. Last night's QuikSCAT pass showed a large and disorganized region of converging winds in the region, with top winds of 25 mph. There is very little dry air in the vicinity, and conditions appear favorable for some slow development of this wave. The wave is poorly organized at present, with no signs of a surface circulation visible on satellite imagery. None of the computer models develop the wave, but they do show relatively low wind shear along the wave's path for the next five days. The wave should continue to track west-northwest over the next 2 - 3 days, and spread heavy rain showers over the northern Lesser Antilles Islands by Wednesday. By Thursday, the trough of low pressure that is pulling 91L to the north should bypass the storm, allowing a high pressure ridge to build in and force 91L due west. NHC is giving 91L a low (less than 30% chance) of developing into a tropical depression by Wednesday.


Figure 2. latest images of Invest 91L.

Pacific typhoons
In the Philippines, the cleanup continues from Tropical Storm Parma, which hit northern Luzon Island Saturday as a Category 1 typhoon. Parma continues to linger offshore the northern tip of the Philippines' Luzon Island, but its heavy rain is now offshore the Philippines. The storm has been blamed for the deaths of 16 people in the Philippines, but did not have the devastating impact that was earlier feared. Storm chaser James Reynolds took some dangerous looking video of Parma in the Philippines.

Super Typhoon Melor became the second Category 5 tropical cyclone of the year over the weekend, but has weakened slightly to a Category 4 super typhoon with 155 mph winds. Melor is expected to recurve to the northeast and pass within 200 miles of Tokyo, Japan, on Wednesday night or Thursday morning.

Jeff Masters

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874. IKE
6. lokakuuta 2009 klo 14:12 (GMT)
NEW BLOG!
Member Since: 9.06.2005 Posts: 23 Comments: 37858
873. Tazmanian
6. lokakuuta 2009 klo 14:10 (GMT)
Quoting hurricane23:
Just dont think upper level conditions will allow for much of anything to get going as noted by tpc in there last outlook.

Looks pretty good for the caribbean at this point.



yup same here



all so too me any thing pass 72hrs has for has mode runs go i find worth less they has they can be nevere right pass 72hrs
Member Since: 21.05.2006 Posts: 5089 Comments: 114075
872. hurricane23
6. lokakuuta 2009 klo 14:07 (GMT)
Just dont think upper level conditions will allow for much of anything to get going as noted by tpc in there last outlook.

Looks pretty good for the caribbean at this point.
Member Since: 14.05.2006 Posts: 8 Comments: 13597
871. Tazmanian
6. lokakuuta 2009 klo 14:05 (GMT)
how many times this year you seen the mode runs say there will be low shear 5 to 14 days out and have mode runs been right about that??
Member Since: 21.05.2006 Posts: 5089 Comments: 114075
870. bwi
6. lokakuuta 2009 klo 14:04 (GMT)
Quoting Canesinlowplaces:
From the RGB loop, it sure looks like a llc is starting - it gets covered up by the big burst of convection on the last couple of frames


About 17n 52w, right?
Member Since: 4.09.2007 Posts: 0 Comments: 1360
869. lowerbamagirl
6. lokakuuta 2009 klo 14:04 (GMT)
I've been lurking all this season and have not been posting. I have a question for y'all though. What do the "Ensemble Models" mean? When I look at the computer models and then the ensemble models, they seem radically different. Not just with this invest, but all year. TIA.
Member Since: 8.07.2007 Posts: 0 Comments: 198
867. OSUWXGUY
6. lokakuuta 2009 klo 14:01 (GMT)
The track forecast will continue to be important down the road, if some semblance of a LLC can be maintained.

If it bends to the southwest or WSW and gets into the eastern Caribbean at around 15-16N then it would likely develop. If it stays on a WNW heading...it will likely struggle for at least 48-60 hours.

866. OSUWXGUY
6. lokakuuta 2009 klo 13:59 (GMT)
Quoting hurricane23:
GFS in particular has done beyond horrible this year when it comes to forcasting upper conditions this season. Models a day or two ago were somewhat indicating a better environment for this thing but as you can clearly see this morning as i pointing out a few days ago it continues to be impacted by moderate shear. Dont see 91L dont much of anything.

Models are just tools.


The GFS never said the shear was going to be low where 91L is currently...

The simple fact is that 91L was drawn north by a weakness in the mid-latitude ridge...and with a sharp south (low) to north (high) shear gradient, this little jog has made all the difference. If our little LLC was down at 14, shear would be low!

864. Tazmanian
6. lokakuuta 2009 klo 13:53 (GMT)
Quoting hurricane23:
GFS in particular has done beyond horrible this year when it comes to forcasting upper conditions this season. Models a day or two ago were somewhat indicating a better environment for this thing but as you can clearly see this morning as i pointing out a few days ago it continues to be impacted by moderate shear. Dont see 91L dont much of anything.

Models are just tools.



thank you 23 was about too say the same thing
Member Since: 21.05.2006 Posts: 5089 Comments: 114075
863. hurricane23
6. lokakuuta 2009 klo 13:50 (GMT)
GFS in particular has done beyond horrible this year when it comes to forcasting upper conditions this season. Models a day or two ago were somewhat indicating a better environment for this thing but as you can clearly see this morning as i pointing out a few days ago it continues to be impacted by moderate shear. Dont see 91L dont much of anything.

Models are just tools.
Member Since: 14.05.2006 Posts: 8 Comments: 13597
862. Canesinlowplaces
6. lokakuuta 2009 klo 13:41 (GMT)
From the RGB loop, it sure looks like a llc is starting - it gets covered up by the big burst of convection on the last couple of frames
Member Since: 12.07.2006 Posts: 0 Comments: 133
861. TampaSpin
6. lokakuuta 2009 klo 13:30 (GMT)
I believe this is true...that 91L is old TD8
Member Since: 2.09.2007 Posts: 177 Comments: 20430
860. TampaSpin
6. lokakuuta 2009 klo 13:23 (GMT)
Quoting Stormchaser2007:



Exactly.

It does bear watching though over the next 48 hours.


Its gotta stay south of 20N if it survives and even then shear might be too strong.
Member Since: 2.09.2007 Posts: 177 Comments: 20430
859. Stormchaser2007
6. lokakuuta 2009 klo 13:21 (GMT)

Quoting JLPR:


yep I was impressed to see it jump from 14N to 17N
now 91L will have to fight to survive until better conditions become available, if they ever do


Exactly.

It does bear watching though over the next 48 hours.
Member Since: 9.06.2007 Posts: 4 Comments: 15718
858. Orcasystems
6. lokakuuta 2009 klo 13:20 (GMT)
I see Parma is getting ready to make landfall again...


AOI

AOI

AOI

AOI


Daily Chuckles in Comments section

Member Since: 1.10.2007 Posts: 81 Comments: 26493
857. TampaSpin
6. lokakuuta 2009 klo 13:19 (GMT)
91L is trying......
Member Since: 2.09.2007 Posts: 177 Comments: 20430
856. TampaSpin
6. lokakuuta 2009 klo 13:17 (GMT)
I believe by this time next year we will be back to LaNina status....its already starting to go the other direction....Said that 2 weeks ago!
Member Since: 2.09.2007 Posts: 177 Comments: 20430
855. JLPR
6. lokakuuta 2009 klo 13:14 (GMT)
Quoting Stormchaser2007:


Well you get my point. The disturbance as a whole has made it too far north.


yep I was impressed to see it jump from 14N to 17N
now 91L will have to fight to survive until better conditions become available, if they ever do
Member Since: 4.09.2007 Posts: 36 Comments: 5223
854. PensacolaDoug
6. lokakuuta 2009 klo 13:14 (GMT)
Joe Bastardi last eve. Make sure you read the comment on the EL NINO.


MONDAY 8 P.M.
BASEBALL IN COLORADO IN OCTOBER... HOW'S THAT WORKING OUT FOR YOU?

People like me love seeing this... the baseball playoffs in Denver this weekend as one of the biggest cold shots in October in years invades. Brutal cold is likely for the games out there this weekend, and it's liable to snow during the weekend. How much? Probably light but guess what, it's a problem.

And next Tuesday, if the series is back in PHL, look out. It's not going to be warm.

The fans at COORS field will be turning blue, along with the beer (see the Coors Commercial).

Ciao for now. *****

MONDAY 7:30 P.M.

NOT MUCH OF A NINO.

The latest MEI value has dropped to .75

There is an interesting comment on this on the MEI site:

http://www.cdc.noaa.gov/people/klaus.wolter/MEI/

"... context of recent positive MEI values, this section features a comparison figure of weak-to-moderate El Nino events that emerge from La Nina conditions in the same calendar year. Note that there was a 30-year hiatus with no such transitions between 1976 and 2006, attesting mostly to the lack of La Nina conditions in this period (as well as the lack of fast transitions from La Nina into El Nino)...."

This observation by Klaus Wolter is very significant as the 1976 example was at the end of the cold PDO and the 2006 example is arguably in the starting time of the new cold PDO. During the warm PDO, the ninos ran rampant for the most part and most of those winters were warm.

The mei contributing value is .75 Current glaam is -.3 The soi contributor for 30 days The sign used is opposite and divided by 10, as is the 90 day is -.25 the 90 day is 0. The Lima contributor (30-day running mean) is plus .4 The Indian Ocean Dipole is giving us a value of 0 Latest Nino 3.4 is .7 the 1.2 is now MINUS .3 The running 90 day only is .8

The Bastardi Scale for all of this is calculated by adding all these, then dividing by all the factors and it comes out to .2. For my purposes, this has weakened to less than a Nino category for the overall global pattern as we are not even at .5 The fact is there are enough cold signals to balance out what warmth there is. Cooling is taking place in all the nino areas I refer my readers to the NOAA El Nino discussion site http://www.cpc.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-stat us-fcsts-web.pdf


I would also like to remind the reader that when I see excellence in sites, I bring them up. The MEI site is outstanding and comes out of the CDC maproom and is maintained by Klaus Wolter. The enso updates, whether I agree or not with the ideas there, should be read by all that are serious about watching this event's effect on the weather. I am transparent with what I am doing and trying to show the whys before the fact. Since most people are skeptical on ideas they do not come up, I have no fear of people stealing my ideas until they are obviously the way to go. For instance, the idea put forth in a recent Drudge Report article by another met mimicked ideas released publicly by ACCUWEATHER ON JULY 15TH. So yes, I may see, with time, some of the ideas here come to front, but again, like that, and NOAA announcing in June the NINO idea we had here in late winter had merit, I expect these things I am showing you will only come to the front after the fact.

If indeed they have merit. That, of course, is not yet determined, which is why these ideas are not being touted and in fact, probably being chastised.

The one that has to be the most aggravating to people that research this is the Lima, Peru, temp. But notice what has happened. Nino 1.2 is colder than normal. Lima told us what was going on before the data actually showed nino 1.2 dropping that much. That -.3 is already below what the model said it would dip too.

Which leaves us with this question... are we having fun yet?

Ciao for now. ******
Member Since: 25.07.2006 Posts: 0 Comments: 519
853. Stormchaser2007
6. lokakuuta 2009 klo 13:13 (GMT)
Quoting JLPR:


it kinda obeyed you by staying at 17N xD


Well you get my point. The disturbance as a whole has made it too far north.
Member Since: 9.06.2007 Posts: 4 Comments: 15718
852. TampaSpin
6. lokakuuta 2009 klo 13:11 (GMT)
The Shear from the SW of about 20kts is hurting 91L from developing!
Member Since: 2.09.2007 Posts: 177 Comments: 20430
851. JLPR
6. lokakuuta 2009 klo 13:11 (GMT)
Quoting Stormchaser2007:


Looks like 91L didnt want to follow my advice.

From lasts nights update,

Shear is very unfavorable to the north of 91L so it would be in its best interest to stay below 18N.


it kinda obeyed you by staying at 17N xD
Member Since: 4.09.2007 Posts: 36 Comments: 5223
850. GTcooliebai
6. lokakuuta 2009 klo 13:08 (GMT)
Quoting TheCaneWhisperer:
ENSO Normal (Neutral)


Nice Graphic
Member Since: 31.08.2009 Posts: 0 Comments: 5628
849. Stormchaser2007
6. lokakuuta 2009 klo 13:07 (GMT)
Quoting JLPR:
windshear of 20 - 25knts giving 91L a hard time



Looks like 91L didnt want to follow my advice.
Last nights update.

Shear is very unfavorable to the north of 91L so it would be in its best interest to stay below 18N.
Member Since: 9.06.2007 Posts: 4 Comments: 15718
848. TampaSpin
6. lokakuuta 2009 klo 13:07 (GMT)
I see 91L is back to yellow.....i really could not figure out yesterday why they ever put it to Orange...as i stated yesterday.
Member Since: 2.09.2007 Posts: 177 Comments: 20430
847. stormsurge39
6. lokakuuta 2009 klo 13:04 (GMT)
Quoting stormsurge39:
Accuweather says there may be some evidence of a closed surface circulation at 16N 50W,
correction, not a closed low instead a surface low.
846. stormsurge39
6. lokakuuta 2009 klo 13:01 (GMT)
Accuweather says there may be some evidence of a closed surface circulation at 16N 50W,
845. ackee
6. lokakuuta 2009 klo 12:58 (GMT)
2009 seasons is almost over if anything does develop looking on SW carrb later in the month 91L will remain a TW
Member Since: 15.07.2008 Posts: 0 Comments: 1341
844. JLPR
6. lokakuuta 2009 klo 12:56 (GMT)
windshear of 20 - 25knts giving 91L a hard time

Member Since: 4.09.2007 Posts: 36 Comments: 5223
843. stormsurge39
6. lokakuuta 2009 klo 12:56 (GMT)
Quoting MahFL:
I see convection building.
It is building and the new convection looks like it trying to wrap NW towards broad level of circulation.
842. MahFL
6. lokakuuta 2009 klo 12:51 (GMT)
I see convection building.
Member Since: 9.06.2004 Posts: 0 Comments: 2913
841. Relix
6. lokakuuta 2009 klo 12:50 (GMT)
I am pretty sure 91L won't develop at all. Quite, quite sure. Upper Level winds and shear won't allow it.
Member Since: 3.08.2006 Posts: 0 Comments: 2639
840. stormsurge39
6. lokakuuta 2009 klo 12:45 (GMT)
Quoting StormW:
Good morning!

TROPICAL WEATHER SYNOPSIS OCTOBER 06, 2009 ISSUED 8:15 A.M. EDT
Storm W, Do you think with an October weather setup fot 91L, that its future would be different then what weve seen all season with other invests and storms?
838. KEEPEROFTHEGATE (Mod)
6. lokakuuta 2009 klo 12:43 (GMT)


91l looks rough
Member Since: 15.07.2006 Posts: 165 Comments: 52390
837. stormpetrol
6. lokakuuta 2009 klo 12:41 (GMT)
91l has a very well defined llc this morning even though convection is lacking.
Member Since: 29.04.2007 Posts: 0 Comments: 7506
836. RitaEvac
6. lokakuuta 2009 klo 12:41 (GMT)
grass is greener now in October than its been all summer
Member Since: 14.07.2008 Posts: 1 Comments: 9625
835. RitaEvac
6. lokakuuta 2009 klo 12:40 (GMT)
Summer continues here with dewpoints near 80 this morning, highs in the 90s and heat index values well over 100+
Member Since: 14.07.2008 Posts: 1 Comments: 9625
834. stormsurge39
6. lokakuuta 2009 klo 12:39 (GMT)
Quoting StormW:
Good morning!

TROPICAL WEATHER SYNOPSIS OCTOBER 06, 2009 ISSUED 8:15 A.M. EDT
Thanks Storm! Which senario are you leaning towards 1 or 2?
833. kmanislander
6. lokakuuta 2009 klo 12:38 (GMT)
Quoting StormW:
Good morning!

TROPICAL WEATHER SYNOPSIS OCTOBER 06, 2009 ISSUED 8:15 A.M. EDT


New burst of convection now attempting to cover the circulation. I suspect there are more surprises in store with 91L

Catch you later.
Member Since: 19.08.2006 Posts: 0 Comments: 15671
832. KEEPEROFTHEGATE (Mod)
6. lokakuuta 2009 klo 12:38 (GMT)
Quoting TropicalBruce:
It looks as if 91L may be encountering difficulties, just like most of its predecessors this season. Hopefully it will soon fizzle out and not give anyone any problems, although it still needs to be watched awhile longer.

Here's to a very subdued tropical Atlantic hurricane season in 2009. May those supressed hurricane seasons continue indefinately.
no you really would not want that canes are heat transfer stations if the heat don't transfer then then may be other abnormal patterns to affect weather some may be extreme
Member Since: 15.07.2006 Posts: 165 Comments: 52390
829. Relix
6. lokakuuta 2009 klo 12:25 (GMT)
Local met here, Ada Monzon, said the system posed no threat as a tropical system to the islands since it wouldn't be able to develop. She does expect for the low pressure to cross PR and die over, but aside from that she expects nothing from this.

My forecast was spot on =P
Member Since: 3.08.2006 Posts: 0 Comments: 2639
827. amd
6. lokakuuta 2009 klo 12:14 (GMT)
91L looks like crap this morning. It seems that the higher shear has come a bit earlier than expected.

Also, Melor is very close to a small Japanese island called Minamidaitojima
Member Since: 29.08.2005 Posts: 0 Comments: 1024
826. TheCaneWhisperer
6. lokakuuta 2009 klo 12:01 (GMT)
ENSO Normal (Neutral)

825. TheCaneWhisperer
6. lokakuuta 2009 klo 11:56 (GMT)
Shear trumps the galley, AGAIN. ARRRGH

I agree with the likes saying El Nino may be on it's way out or Modoki style anyway.
824. homelesswanderer
6. lokakuuta 2009 klo 11:53 (GMT)
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
526 AM CDT TUE OCT 6 2009



DISCUSSION...
LATEST SFC ANALYSIS SHOWS HIGH PRESSURE OVER THE EAST COAST
CONTINUING TO MOVE EAST...PROVIDING A VERY MOISTURE RICH SOUTHERLY
FLOW OFF THE GULF. THIS IS ESPECIALLY TRUE OVER SE TX...WHERE
TEMPS/DEWPTS ARE IN THE UPPER 70S TO NEAR 80 ON THE COAST...WHICH
IS VERY UNUSUAL EVEN FOR EARLY OCTOBER.


TEMPS TODAY WILL REACH NEAR 90/LOWER 90S AHEAD OF THE FRONT ACROSS
THE I-10 CORRIDOR...WHICH IS A COUPLE OF DEGREES SHY OF RECORD
VALUES
...TO THE UPPER 80S ACROSS INLAND SE TX/C LA. LOWS TONIGHT
WILL ONLY REACH THE LOWER TO MID 70S ONCE AGAIN. KEEP IN MIND THE
NORMALS FOR THIS TIME OF YEAR SHOW NEAR 60 FOR LOWS AND NEAR 80
FOR HIGHS!

LETS DO IT AGAIN FOR FRI...WITH ANOTHER STRONG STORM SYSTEM TO
BRING ANOTHER FRONT ACROSS THE REGION LATE FRI/SAT TIME
FRAME...ALONG WITH ANOTHER GOOD CHANCE OF SHRA/TSRA. THIS FRONT
MAY HAVE A LITTLE MORE S PROGRESSION...EXPECTING THE FRONT TO HANG
UP ACROSS THE N GULF.
THE GFS/ECMWF HAVE SLIGHT TIMING DIFFERENCES
IN FROPA...AND HOW MUCH CLEARING AND CAA WILL TAKE PLACE THIS
WEEKEND.

The year of shear and stalling cold fronts. Lol.

Beaumont, Texas (Airport)
Updated: 58 min 39 sec ago
Scattered Clouds
79 °F
Scattered Clouds
Humidity: 100%
Dew Point: 79 °F

A perfect score. :)
Member Since: 15.08.2008 Posts: 10 Comments: 3665

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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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