Sandy forms south of Jamaica; TD 19 forms in middle Atlantic

By: Dr. Jeff Masters , 9:48 PM GMT on October 22, 2012

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The Hurricane Hunters found a band of 40 mph winds on the southeast side of Tropical Depression Eighteen this afternoon, prompting NHC to upgrade the system to Tropical Storm Sandy. Sandy is over very warm waters of 29.5°C, is in a moist environment, and has light wind shear of 5 - 10 knots. These conditions are very favorable for intensification, and Sandy's heavy thunderstorms are steadily organizing into curved spiral bands, as seen on satellite loops.


Figure 1. Late afternoon satellite image of Tropical Storm Sandy.

Forecast for Sandy
Wind shear is forecast to be in the low to moderate range, 5 - 20 knots, through Wednesday afternoon. This should allow continued development of Sandy, and rapid development is possible. The latest SHIPS model forecast is calling for a 52% chance that Sandy's winds will increase by 30 mph over a 24-hour period. The 5 pm EDT NHC Wind Probability Forecast gave a 25% chance that Sandy will be a hurricane by 2 pm EDT Wednesday, when the center should be close to Jamaica. Wind shear will rise to a high 25 - 30 knots by Thursday, which should weaken Sandy. By Friday, Sandy should be in the Central or Eastern Bahamas, and wind shear may increase further, making Sandy more of a hybrid subtropical storm. It is unclear at this point whether or not the trough pulling Sandy to the north will be strong enough to pull the storm all the way out to sea to the northeast; a very complicated steering environment will develop late this week, and it is possible that a narrow ridge of high pressure could build in over Sandy, and force the storm to the northwest, with a potential threat to the Northwestern Bahamas and U.S. East Coast by Saturday, as predicted by the ECMWF model. Sandy is not a threat to be a hurricane at that time, due to very high wind shear. Heavy rains are the main threat from Sandy.

Sandy's place in history
Sandy is the eighteenth named storm of the 2012 Atlantic hurricane season, tying this year with 1969 for seventh busiest Atlantic season since record keeping began in 1851. Here are the busiest Atlantic hurricane seasons on record:

2005 (28 named storms)
1933 (20 named storms, according to a new re-analysis)
1887 (19 named storms)
2010 (19 named storms)
2011 (19 named storms)
1995 (19 named storms)
1969 (18 named storms)
2012 (18 named storms)

There are two weak and short-lived storms from 2012 that stayed far out sea, and would likely have gone unnoticed in the pre-satellite era (before 1960): Tropical Storm Joyce and Tropical Storm Oscar. And while this season has been very busy for total number of named storms, we've had a below-average number of major hurricanes (just Hurricane Michael), and the total destructive power of the 2012 hurricane season as measured by the Accumulated Cyclone Energy (ACE) is only about 20% above average. See our newly-launched Accumulated Cyclone Energy (ACE) page for a storm-by-storm breakdown of this years ACE, plus historical ACE stats for each ocean basin. Thanks go to Angela Fritz for putting this together!


Figure 2. MODIS satellite image of TD 19 taken at 12:30 pm EDT October 22, 2012. Image credit: Navy Research Lab, Monterey.

Tropical Depression Nineteen forms in the middle Atlantic
Tropical Depression Nineteen is here, and appears poised to become Tropical Storm Tony by early Tuesday morning. TD 19 has a modest area of heavy thunderstorms, as seen on visible satellite images, and dry air from the upper-level low pressure system that it formed underneath is slowing development. TD 19 is over warm waters of 28°C, and wind shear is a moderate 10 - 20 knots. This shear is forecast to remain in the moderate range until Wednesday morning, which should allow TD 19 to develop into Tropical Storm Tony over the next day. On Wednesday, TD 19 is expected to encounter high wind shear of 20 - 30 knots, which should prevent further strengthening. TD 19 will not threaten any land areas, and is unlikely to reach hurricane strength.

Jeff Masters

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Quoting ncstorm:
From Facebook-how true is this?

Henry Margusity Fan Club
Let me be clear, a Neg NAO means a storm should be along the coast despite what the GFS says.

It's definitely difficult to get a storm to recurve in a negative NAO, but it doesn't mean that it won't.
Member Since: July 6, 2010 Posts: 113 Comments: 32346
Good Morning/Evening

Looks like Sandy is still pushing her twin off to the East. Her circulation doesn't look strong enough to reabsorb the spin off blob.
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06z Nogaps
Member Since: August 19, 2006 Posts: 13 Comments: 15745
From Facebook-how true is this?

Henry Margusity Fan Club
Let me be clear, a Neg NAO means a storm should be along the coast despite what the GFS says.
Member Since: August 19, 2006 Posts: 13 Comments: 15745


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Center appears to be:

Coordinates: 13.3667N 77.8833W

with a 997MB
Member Since: August 14, 2008 Posts: 4 Comments: 4977
Good morning/Evening everyone. I have a workshop today, so got to sleep in a little. My thoughts and prayers to Haiti, this could be very bad for them.
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Quoting TropicalAnalystwx13:

No recon, 19L is no concern.

If recon went to TD19 they would find its now a TS. Satellite presentation looks like a TS
Member Since: September 30, 2007 Posts: 9 Comments: 15940
I wrote a blog on Sandy and TD19, check it out.
I have to go to school early again, bye everyone. It should be interesting to see what Sandy has done when I get home.
Member Since: March 16, 2012 Posts: 127 Comments: 7952
We will see if my theory works in regards to rapid intensification. I've been going back through some of the tropical cyclone image archives from storms during the 2005, 2008, and 2010 Atlantic hurricane season. One thing I've noticed is that, just before rapid intensification begins, very deep convection fires in the outer bands, and then cloud tops warm and overshooting tops begin near the center.

Watch Sandy:



If we have a rapidly intensifying cyclone this afternoon we'll know my theory worked.
Member Since: July 6, 2010 Posts: 113 Comments: 32346
Quoting AussieStorm:

Is recon going to fly into 19L or they not to worried about it now?

No recon, 19L is no concern.
Member Since: July 6, 2010 Posts: 113 Comments: 32346

Good morning Sandy and all you others ...
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Quoting TropicalAnalystwx13:
Recon is now about to enter into Sandy, we shall see what they find. Something tells me it won't be below 60 mph.


Is recon going to fly into 19L or they not to worried about it now?
Member Since: September 30, 2007 Posts: 9 Comments: 15940
Sandy....


19L

Click for bigger image
Member Since: September 30, 2007 Posts: 9 Comments: 15940
Recon is now about to enter into Sandy, we shall see what they find. Something tells me it won't be below 60 mph.

Member Since: July 6, 2010 Posts: 113 Comments: 32346
Quoting AussieStorm:
Anyone else notice 19L has the same D.I numbers as Sandy? Could we see an upgrade to Tony soon?



Good catch Aussie.
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Quoting CybrTeddy:
My guess is we will have TS Tony by the end of the day.


Sun is about to come over TS Sandy.

nice banding on 19L.








But dry are could become an issue soon.
Member Since: September 30, 2007 Posts: 9 Comments: 15940
My guess is we will have TS Tony by the end of the day.


Sun is about to come over TS Sandy.
Member Since: July 8, 2005 Posts: 259 Comments: 24255
a lot more ensembles are now keeping the North path instead of NE
00z







Member Since: August 19, 2006 Posts: 13 Comments: 15745
Anyone else notice 19L has the same D.I numbers as Sandy? Could we see an upgrade to Tony soon?

Member Since: September 30, 2007 Posts: 9 Comments: 15940
Quoting GTcooliebai:
Good Morning everyone...Sandy and an ULL to the north of her.


Is that ULL causing this projected shear?


I guess this AC is not helping either.
Member Since: September 30, 2007 Posts: 9 Comments: 15940
so even though the GFS goes NE rather than North it is still the farthest west than the Euro and CMC after exiting cuba and tags south florida
Member Since: August 19, 2006 Posts: 13 Comments: 15745
My forecasts for Sandy and TD19.
Member Since: March 16, 2012 Posts: 127 Comments: 7952
Quoting flcanes:
so my sandy forecast is over 5 days
today:expect to attain 60mph winds
tommorow:jaimaca landfall
thursday:cuba landfall
friday:attains cat1 and hits bahamas

SO I guess you don't agree with this...



with the help of this?
Member Since: September 30, 2007 Posts: 9 Comments: 15940
Good Morning everyone...Sandy and an ULL to the north of her.

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so my sandy forecast is over 5 days
today:expect to attain 60mph winds
tommorow:jaimaca landfall
thursday:cuba landfall
friday:attains cat1 and hits bahamas
Member Since: August 20, 2012 Posts: 13 Comments: 1254
Quoting psuweathernewbie1:
Any status updates on the hurricane hunter aircraft going into Sandy this morning? The NHC mentioned it in the 5am EDT discussion.


They're still on their way, but they're close. They're about 270 miles away from Sandy. I would expect them to start descending in 15 to 20 min.
Member Since: August 14, 2008 Posts: 4 Comments: 4977
Quoting SFLWeatherman:
They are going in to Sandy now!!
They are still a couple hundred miles north of Sandy now.
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Quoting psuweathernewbie1:
Any status updates on the hurricane hunter aircraft going into Sandy this morning? The NHC mentioned it in the 5am EDT discussion.
Link
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They are going in to Sandy now!!
Quoting psuweathernewbie1:
Any status updates on the hurricane hunter aircraft going into Sandy this morning? The NHC mentioned it in the 5am EDT discussion.
Member Since: May 23, 2012 Posts: 0 Comments: 4716
Quoting Grothar:


I think the pressure gradient difference alone would cause extremely windy conditions even if Sandy were to stay well off the coast. She looks like she might be a slow mover which would cause severe beach erosion. Even if there were no I would say the possibility is high that a good portion of the coast would have TS watches at least. Looks like it will go right over Jamaica, eastern Cuba and right through the central Bahamas.


More likely High Wind advisories. This morning Sandy looks lopsided a bit with dry air to her north & west, which has inhibited development. If she stays lopsided you will see just HW advisories or South Fla.
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84HR

Member Since: May 23, 2012 Posts: 0 Comments: 4716
Any status updates on the hurricane hunter aircraft going into Sandy this morning? The NHC mentioned it in the 5am EDT discussion.
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Good Morning
Member Since: August 14, 2008 Posts: 4 Comments: 4977
Member Since: May 23, 2012 Posts: 0 Comments: 4716
6Z!!
Member Since: May 23, 2012 Posts: 0 Comments: 4716
This is from me yesterday and this is the 6Z GFS

Member Since: May 23, 2012 Posts: 0 Comments: 4716
Good morning. Sandy's looking rather blobbish right now:



I continue to believe the GFS track solution, and it appears the NHC is leaning that way as well. I'd say South Florida could see some decent rain and some wind with high surf and rip currents being the only threats for the rest of the East Coast.
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WOW!!


Member Since: May 23, 2012 Posts: 0 Comments: 4716
Good morning everyone, Sandy is looking better and we should have Tony today. My NWS has started mentioning the possibility of Sandy tracking into the eastern lakes.
Member Since: March 16, 2012 Posts: 127 Comments: 7952
Hi all... not sure how much time I'll have to post in the blog today, but I will certainly be monitoring the progress of Sandy.

If I have any news of interest from the local scene, I'll post that, and will try to get a blog post of my own up sometime in the next 24 hours.

I'm just thinking it's pretty amazing I haven't really needed to post much in my blog this year, despite the 18 named storms.... lol

Have a good day!
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good morning folks..7-day for the tampa bay area.......
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Quoting Hurricanes305:
Sandy getting better organize after some dry air overnight. Its now building a CDO and by 11am we could see a 50 or 60mph cyclone and a another westward shift in the cone. As a big low over the Atlantic will block any NE turn out to sea and a narrow area of high pressure might step in and force NW towards The Northwest Bahamas and Florida as been mentioned by Dr. M for a couple of blogs now.
Good morning. IDK if it is my eyes but it looks like a very slow movememnt to the NW now.

Link
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6Z GFS go W now S FL is going to get big rain!!
Member Since: May 23, 2012 Posts: 0 Comments: 4716
Sandy getting better organize after some dry air overnight. Its now building a CDO and by 11am we could see a 50 or 60mph cyclone and a another westward shift in the cone. As a big low over the Atlantic will block any NE turn out to sea and a narrow area of high pressure might step in and force NW towards The Northwest Bahamas and Florida as been mentioned by Dr. M for a couple of blogs now.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
519. vis0
Lets see how Tropical Storm Sandy - 201210-23 .moves. My 2 cents?,: please read the blog (if read, yes i state i created a device that can influence weather:) Lets see if it becomes an Express superstorm, though i don't like the way superstorm is used anytime 2 Low formations join.

http://www.wunderground.com/blog/vis0/comment.htm l?entrynum=109
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The EURO ensemble mean is really impressive,


They are very confident this will get knocked to the NW by the low in the Atlantic.

As is the operational run


Consistent for 2-3 days on a "doomsday" like scenario.
1993 Storm of the Century's pressure bottomed out to 960 mlb. The EURO shows the strongest East Coast storm in quite sometime. Very interesting.
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All times in GMT. Derived from NHC_ATCF data for TropicalStormSandy @ 23Oct.6am

GCM-GrandCayman :: PVA-Providencia :: ADZ-SanAndres :: MBJ-MontegoBay

The easternmost unlabeled dot is where Invest99L became TropicalDepressionEighteen
The next unlabeled dot southsouthwest is where TD.18 became TropicalStormSandy
The southernmost dot on the longest line is TS.Sandy's most recent position

The longest line is a straightline projection through TS.Sandy's 2 most recent positions to its closest approach to an inhabited coastline.
23Oct.6am: TS.Sandy had been heading toward passage 5.8miles(20kilometres)WNWest of GrandCayman

Click this link to the GreatCirleMapper for more info
And the previous mapping for comparison
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Quoting KoritheMan:


Wasn't that cyclonebuster's idea? He called them "tunnels", I believe.


Yes yes! I couldn't remember the details!
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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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