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 bigwes6844:
SANDY SHOULD BE UP TO 60 MPH AT 5 EDT. RI IS HAPPENING


no it isn't.
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If you get more good ones i will put them up!
Quoting nigel20:

Thanks much!
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the NHC track is east of the models but yet the HPC is west of the GFS..didnt they have a conference call..arent these agencies suppose to come to a mutual agreement when it comes to hurricanes?
Member Since: August 19, 2006 Posts: 13 Comments: 16223
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting SFLWeatherman:
If you have FB go to this Link

Thanks much!
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Quoting washingtonian115:
I can't believe a storm by the name of Sandy might affect me...Hopefully TWC doesn't use those ugly names...


"You betta shape up, because you need a plan"
Member Since: August 19, 2006 Posts: 13 Comments: 16223
I can't believe a storm by the name of Sandy might affect me...Hopefully TWC doesn't use those ugly names...
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Quoting ncstorm:


Sandy is coming..

Yes indeed
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If you have FB go to this Link
Quoting nigel20:

I'm in Arcadia, Kingston, Jmaica.
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Quoting Grothar:
FIM9 as it crosses Jamaica.




The FIM as is moves into the Bahamas.




Again the only thing I do not understand with this system, is that each model has the worst weather and winds in the NW quadrant rather than the NE. I wonder is anyone could explain why.

It's Irish. lol
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Quoting SFLWeatherman:
Where are you i will put it up on my Weather blog on FB

I'm in Arcadia, Kingston, Jmaica.
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Quoting WxLogic:


Pressure gradient due to the orientation of the E CONUS/ W ATL high to the N and NW of Sandy as it noses down on the W side prior to the next approaching TROF. That would be my explanation of the pooling of moisture on the N and W side of Sandy on those runs.


The local met here said that the pressure gradient could give us stronger winds that the wind field from Sandy. Makes sense.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting ecupirate:
Im hoping it leaves Eastern NC alone. Irene was a mess and the last thing I want is to have to clean up trees again.


If the CMC and Euro are right, you will be cleaning up more than trees..close brush with NC according to those models..
Member Since: August 19, 2006 Posts: 13 Comments: 16223
Quoting BoyntonBeachFL:
Lake Worth Pier on Friday morning based on GFS, winds 44 knots gusting to 61 knots.

Link


No surprise given how one sided to the west this system is going to be, if one believes the GFS.
Member Since: July 8, 2005 Posts: 259 Comments: 24574
Link
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Quoting kmanislander:


I have favoured the CMC track from several days ago and still lean that way with Sandy passing just immediately West of Jamaica but East of the Cayman Islands. Cayman Brac and Little Cayman would get more of the system than Grand Cayman would if that happens

Which island is Pottery on?
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Quoting GeorgiaStormz:


I know on www.twisterdata.com if you click on GFS and then on winter, you can then look at snow depth for any hour.
Would be useful if the GFS decided to bring the Noreaster back again.

Also Wunderground Models/Maps
has a snowfall feature under GFS and ECMWF

The ECMWF snowfall forecast for 174hrs shows a major snowfall event for Pennsylvania and New York:



Where is the key to that image?
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Im hoping it leaves Eastern NC alone. Irene was a mess and the last thing I want is to have to clean up trees again.
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850MB winds in the same model run. Surface reduction would still yield TS conditions.



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Lake Worth Pier on Friday morning based on GFS, winds 44 knots gusting to 61 knots.

Link
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Quoting GeorgiaStormz:


I know on www.twisterdata.com if you click on GFS and then on winter, you can then look at snow depth for any hour.
Would be useful if the GFS decided to bring the Noreaster back again.

Also Wunderground Models/Maps
has a snowfall feature under GFS and ECMWF

The ECMWF snowfall forecast for 174hrs shows a major snowfall event for Pennsylvania and New York:



That was it, it was the ECMWF map. Thanks! I will have to bookmark that one!
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Quoting nigel20:
I took these about 20 minutes ago.





Sandy is coming..
Member Since: August 19, 2006 Posts: 13 Comments: 16223
Where are you i will put it up on my Weather blog on FB
Quoting nigel20:
I took these about 20 minutes ago.



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Press going down now at 996.1
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Based on the EMCWF snowfall model, it appears that after copious amounts of moisture are dumped as snow in NY, PA, and MD, the whole batch of precipitation begins to drift south towards the end of the WU snowfall model output at 180 hrs, and this is on October 30th.

This means if the snow area was to rotate south a tad more, it could snow in DC on the 31st before the low takes off north, making Washingtonian115 a very unhappy lady.

I must go now, and will be back around lunchtime.
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I took these about 20 minutes ago.



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GFS model shifted left if trends continue the nw bahamas are going to get nailed bad . I have a gut feeling se florida will be under a tropical storm watch towards thurs or friday very bad weather will be close or over the coastal areas if the track over the nw bahamas does materialize
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Halo 4 Soundtrack is out!!!:)
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Quoting Grothar:
FIM9 as it crosses Jamaica.




The FIM as is moves into the Bahamas.




Again the only thing I do not understand with this system, is that each model has the worst weather and winds in the NW quadrant rather than the NE. I wonder is anyone could explain why.


Pressure gradient due to the orientation of the E CONUS/ W ATL high to the N and NW of Sandy as it noses down on the W side prior to the next approaching TROF. That would be my explanation of the pooling of moisture on the N and W side of Sandy on those runs.
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Sandy go out to sea!.Those poor people in the Caribbean will have to deal with her because she is land locked.
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Sandy's MLC and LLC don't seem stacked, but they look very close.

Member Since: July 6, 2010 Posts: 113 Comments: 32812
06Z GFS @ 78hrs. Notice how tight the gradient is on the west side compared to the east. SEFL would be under a TS warning in this model run.

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633. 7544
Quoting Grothar:


morning could se fl get more of sandy than expected esp if she builds in on the western side today now hmm only 3 days out
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Quoting ProgressivePulse:


Widening wind field is the key there. Irene's TS wind field stayed just offshore on it's closest approach to FL. Move Sandy over 50 miles or so and widen the wind field and you'll have a much different experience. On top of that, some of the models are indicating a Wrn loaded storm, unlike the traditional east loaded sheared cyclone.


I remember that. We had Tropical Depression conditions for 5 minutes then it was gone... That was my experience with Irene here in Palm Coast.
Member Since: July 1, 2008 Posts: 13 Comments: 7437
Quoting reedzone:


Just the change in the temp really.. Plus the wind field will widen. Other then that, the pressure should continue to drop and conditions will only get worse.


Widening wind field is the key there. Irene's TS wind field stayed just offshore on it's closest approach to FL. Move Sandy over 50 miles or so and widen the wind field and you'll have a much different experience. On top of that, some of the models are indicating a Wrn loaded storm, unlike the traditional east loaded sheared cyclone.
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Quoting ecupirate:


Someone posted a graphic of the GFS snowfall forecast for the US. That is what I am looking for.


I know on www.twisterdata.com if you click on GFS and then on winter, you can then look at snow depth for any hour.
Would be useful if the GFS decided to bring the Noreaster back again.

Also Wunderground Models/Maps
has a snowfall feature under GFS and ECMWF

The ECMWF snowfall forecast for 174hrs shows a major snowfall event for Pennsylvania and New York:

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Quoting ProgressivePulse:
But one should also note that unlike Irene in 2011 there may be some Barclonic Forcing going on at that time which could greatly change the impacts felt on the East Coast.
Right,I think Irene weakened considerably when it pulled in the air from land.
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She doing good now!!!
Quoting nigel20:
It's not looking good for us (Jamaica) ATM.
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Quoting ProgressivePulse:
But one should also note that unlike Irene in 2011 there may be some Barclonic Forcing going on at that time which could greatly change the impacts felt on the East Coast.


Just the change in the temp really.. Plus the wind field will widen. Other then that, the pressure should continue to drop and conditions will only get worse.
Member Since: July 1, 2008 Posts: 13 Comments: 7437
It's not looking good for us (Jamaica) ATM.
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But one should also note that unlike Irene in 2011 there may be some Barclonic Forcing going on at that time which could greatly change the impacts felt on the East Coast.
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Good morning all!

NEWS RELEASE
October 23 2012 at 8 a.m..

BULLETIN No:7 TROPICAL STORM WARNING and HURRICANE WATCH IN EFFECT …TROPICAL STORM SANDY BEGINS TO TURN TOWARDS THE NORTH-NORTHEAST

TROPICAL STORM WARNING and HURRICANE WATCH IN EFFECT …TROPICAL STORM SANDY BEGINS TO TURN TOWARDS THE NORTH-NORTHEAST


The TROPICAL STORM WARNING and HURRICANE WATCH remain in effect for Jamaica as Tropical Storm Sandy makes a turn in the direction of the island.

This means that tropical storm conditions, including possible sustained wind speeds of 34-63 knots or 63-118 km/h (40-74 mph), are expected in 36 hours or less and that hurricane conditions also pose a possible threat to the country within 48 hours.

At 7:00 a.m. the centre of Tropical Storm Sandy was located near Latitude 13.4 degrees North, Longitude 77.9 degrees West, or about 525 kilometres (325 miles) south-southwest of Kingston, Jamaica or 400 kilometres (250 miles) south of the Pedro Cays.

Tropical Storm Sandy has begun to move towards the north-northeast near 6 km/h (3 mph) and this motion is expected to continue with some increase in forward speed today and tomorrow. On this forecast track, the centre of Sandy will begin to move across Jamaica, from south to north, on Wednesday afternoon.

Maximum sustained winds remain near 75 km/h (45 mph), with higher gusts; however, strengthening is expected during the next 24 hours and Sandy is forecast to be a hurricane nearing Jamaica tomorrow. Tropical storm force winds extend outward up to 150 kilometres (90 miles), primarily east of the centre.

Over the next 24-36 hours, rainfall is expected to increase significantly over Jamaica to produce over 250 millimeters (10 inches), especially over central and eastern sections of the island. Flash flooding and landslides are likely. Tropical storm conditions are expected by early Wednesday morning and hurricane conditions later in the day. Storm surge is also possible along the southeastern coastline of the island.

All small craft operators including fishers from the cays and banks should by now have completed all the necessary safety precautions and are advised to remain in safe harbour until all warning messages have been lifted and wind and sea conditions have returned to normal

It is likely that a Hurricane Warning will be issued for Jamaica later today. The next Bulletin on Tropical Storm Sandy will be issued at 11:00 a.m. today.


pef
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Wow as this system moves further inland and weakens its pull on the very cold canadian airmass greatly increases per the Euro:


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6Z GFS ENSEMBLE!! all of them at 78HR!!






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If the eroupean models are right...

...Snowicane Sandy!
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Quoting GeorgiaStormz:


GFS doesnt have the noreaster, so no snow.


Someone posted a graphic of the GFS snowfall forecast for the US. That is what I am looking for.
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Quoting Grothar:





That's pretty close lol. Just going off the effects we had when Irene 2011 passed through a similar location as a CAT 3. Windy but not too bad.

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Miami NWS Disco

AFTER COLLABORATING WITH MELBOURNE AND KEY WEST IT WAS AGREED THAT
WE WILL NOT INCLUDE TROPICAL WORDING IN THE CWF IN THIS MORNING
PACKAGE UNTIL WE ARE MORE CERTAIN OF THE EXTENT OF THE WIND FIELD.

A MORE CLEAR PICTURE OF THE EXTENT OF THE TROPICAL FORCE WINDS IS
EXPECTED IN THE NEXT ADVISORIES WITH THE POSSIBILITY THAT THE
WORDING *TROPICAL STORM CONDITIONS POSSIBLE* CAN BE ADDED TO THE
CWF IN THE NEXT PACKAGES. ALSO...NEAR GALE CONDITIONS ARE POSSIBLE
OVER THE COASTAL WATERS BEGINNING ON THURSDAY AFTERNOON BASED ON
THE WINDS USED IN THIS FORECAST PACKAGE. HOWEVER, NO GALE WATCH IS
ISSUED AT THIS TIME. A HIGH RISK OF RIP CURRENTS WILL CONTINUE
FOR THE ATLANTIC WATERS BETWEEN NOW AND FRIDAY WITH A VERY GOOD
POSSIBILITY THAT IT COULD BE EXTENDED BEYOND FRIDAY DEPENDING ON
THE EXACT PATH OF SANDY.
Member Since: September 10, 2007 Posts: 0 Comments: 11539
FIM9 as it crosses Jamaica.




The FIM as is moves into the Bahamas.




Again the only thing I do not understand with this system, is that each model has the worst weather and winds in the NW quadrant rather than the NE. I wonder is anyone could explain why.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting reedzone:
Just think what would happen if this became a reality. Evacuations from Maryland to Maine, winter storm warnings inland.. the Superstorm of 2012, Storm of the Century. This would beat the 1993 Superstorm in terms of pressure. You would see Hurricane force winds from Cape Cod to Long Island, perhaps New Jersey and PA since it all backs to the west. It would be a rare phenomenon if this panned out.


This is the EURO and it's ensemble members are in strong agreement of a north to NNW track after the Bahamas. Not to mention the NAO is very low, which usually indicates an East Coast Storm of some sort. Elements to consider.


Nothing would match that earlier Euro run a few days back or this current CMC:



I think that other Euro was 920mbs or 930mbs and had an effect over practically the whole US east of the Mississippi River and brought the snow line to northern GA.
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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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