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 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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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.
I am not evacuating for anything!LOL
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Quoting GeorgiaStormz:


Its a very large monsoonal system that wont take too much of a beating, since it is not coming in as a very strong system, and passes over cuba fairly quickly.

Heck even Jamaica is very mountainous.

The circulation of a 70-knot hurricane will be disrupted at least slightly by Cuba. I'd agree if the storm doesn't end up becoming a hurricane.
Member Since: July 6, 2010 Posts: 113 Comments: 31565
Quoting washingtonian115:
Why isn't anyon mentioning the high terrain over Cuba that Sandy has to cross?.


Its a very large monsoonal system that wont take too much of a beating, since it is not coming in as a very strong system, and passes over cuba fairly quickly.

Heck even Jamaica is very mountainous.
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The 006Z late cycle




The 12Z early cycle.



Member Since: July 17, 2009 Posts: 69 Comments: 25489
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.
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Quoting ecupirate:
Anyone have a link to the GFS Model snow forecast? Someone posted the image yesterday (it showed snow in the mid atlantic as Sandy phases and turns into a Noreaster)

Thanks!


GFS doesnt have the noreaster, so no snow.
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Quoting CybrTeddy:


A system that isn't vertically stacked in the Caribbean? In 2012? No way! Seems to be the story of the last few seasons, ever since Dolly.

The two centers aren't horribly far apart, and Sandy should resolve the stacking issue by tomorrow.
Member Since: July 6, 2010 Posts: 113 Comments: 31565
Why isn't anyon mentioning the high terrain over Cuba that Sandy has to cross?.
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Quoting ProgressivePulse:


I don't think it will come too close to FL however a track over the NWrn Bahamas area is looking more and more likely with each passing model run. That would make for a pretty nasty day along the East Coast. One thing is for sure, the beaches will take the hardest punch here.


Member Since: July 17, 2009 Posts: 69 Comments: 25489
Anyone have a link to the GFS Model snow forecast? Someone posted the image yesterday (it showed snow in the mid atlantic as Sandy phases and turns into a Noreaster)

Thanks!
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What im seeing is the model runs themselves are east, but quite a few ensembles stay west the whole time, and then some of them go east similiar to the operational models, and then curve back west and move westward into the northeast.
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Member Since: July 17, 2009 Posts: 69 Comments: 25489
601. JRRP
Quoting SFLWeatherman:
They all going W now

I do not think so
Link
Member Since: August 16, 2007 Posts: 0 Comments: 5482
Quoting TropicalAnalystwx13:

It's definitely difficult to get a storm to recurve in a negative NAO, but it doesn't mean that it won't.


I never realized the NAO had gone so negative.
If only it was january.
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Quoting SFLWeatherman:
Will S FL be in the Cone at 11AM??



I don't think it will come too close to FL however a track over the NWrn Bahamas area is looking more and more likely with each passing model run. That would make for a pretty nasty day along the East Coast. One thing is for sure, the beaches will take the hardest punch here.
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Not expecting much intensification until late this evening, the core needs to become better established, and we all know how long that takes. 50mph tops today, with intensification beginning in earnest tomorrow.
Member Since: July 8, 2005 Posts: 259 Comments: 23638
596. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #13
TROPICAL DEPRESSION 25
21:00 PM JST October 23 2012
====================================

SUBJECT: Tropical Depression In Sea East Of Mindanao

At 12:00 PM UTC, Tropical Depression (1000 hPa) located at 8.3N 128.1E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west at 9 knots.

Dvorak Intensity: T2.0

Forecast and Intensity
========================

24 HRS: 10.2N 124.5E - 35 knots (CAT 1/Tropical Storm) Overland Philippines
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Quoting ncstorm:
Everytime I tried to leave, i find something else but good gracious, the CMC ensembles have shifted west..okay Im off to do some work..have fun



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
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Wow!!
Quoting ncstorm:
Everytime I tried to leave, i find something else but good gracious, the CMC ensembles have shifted west..okay Im off to do some work..have fun

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Sandy now being sheared by the off center anticyclone.
All of the deep convection is being pushed off to the East of the circulation center and preventing the system from becoming vertically aligned.

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Everytime I tried to leave, i find something else but good gracious, the CMC ensembles have shifted west..okay Im off to do some work..have fun

Member Since: August 19, 2006 Posts: 13 Comments: 14629
Will S FL be in the Cone at 11AM??

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Good morning

With Sandy now a sub 1000 mb storm amd likely to strengthen some today, the present steering would seem to suggest a bit of a nudge to the NNW as it comes up below Jamaica. The ridge to the N is still in the process of propagating to the East and as it flattens over Fla. the current motion to the NNE should ease to one of due North or NNW in the short term.

This is what I will be watching for later today.

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The models included on this map continue their west slide in the Bahamas. NHC again the eastern outlier.

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HPC 5 day forecast

Member Since: August 19, 2006 Posts: 13 Comments: 14629
Quoting Stormchaser2007:
Not stacked.

000
URNT12 KNHC 231240
VORTEX DATA MESSAGE AL182012
A. 23/11:51:40Z
B. 13 deg 22 min N
077 deg 53 min W
C. 850 mb 1391 m
D. 22 kt
E. 307 deg 29 nm
F. 044 deg 24 kt
G. 307 deg 88 nm
H. 997 mb
I. 17 C / 1519 m
J. 20 C / 1519 m
K. 16 C / NA
L. NA
M. NA
N. 1345 / 8
O. 0.02 / 3 nm
P. AF301 0218A SANDY OB 08
MAX OUTBOUND AND MAX FL WIND 48 KT SE QUAD 12:18:30Z
Sfc cntr 340/12nm from flight level center. Flight level center up against convection


A system that isn't vertically stacked in the Caribbean? In 2012? No way! Seems to be the story of the last few seasons, ever since Dolly.
Member Since: July 8, 2005 Posts: 259 Comments: 23638
from my local NWS in Wilmington, NC...will be back later

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...EXCITING YET UNCERTAIN DEVELOPMENTS IN THE
EXTENDED RELATED TO NEWLY DEVELOPED TROPICAL STORM SANDY AND HOW SHE
WILL EVOLVE THROUGH THE WKND.

UNFORTUNATELY...OVER THE PAST 2 DAYS...GUIDANCE HAS ACTUALLY COME
INTO LESS-AGREEMENT, AND THERE ARE TWO "CAMPS" AT THIS TIME. THE
GFS-CAMP DEVELOPS SANDY RAPIDLY NEAR CUBA AND THEN PUSHES HER WELL
OFF TO THE NORTHEAST AWAY FROM THE US EAST COAST. THE MORE TROUBLING
ECMWF/CMC CAMP DEVELOPS SANDY IN ROUGHLY THE SAME TIME FRAME...AND
THEN BRINGS HER ALMOST DUE NORTH INTO NEW ENGLAND AS A VERY
STRONG...REALLY AN HISTORIC...SYSTEM.

THE MAJOR DIFFERENCES LIE IN THE EVOLUTION OF THE 500MB TROUGH
PROGGED TO DEVELOP AND DIVE INTO THE GREAT PLAINS EARLY NEXT
WKND...AND THE LEVEL OF RIDGE/BLOCKING THAT OCCURS DOWNSTREAM ACROSS
THE NORTH ATLANTIC. THE GFS HAS A WEAKER TROUGH WHICH THEN CANNOT
CAPTURE SANDY TO SPIN HER BACK TO THE NORTH...AND A MORE RAPIDLY
WEAKENING UPPER RIDGE WHICH ENABLES SANDY TO DRIFT EAST BENEATH THE
WEAKNESS. THE ECMWF/CMC SHOW AN ANOMALOUSLY STRONG TROUGH WHICH IS
ABLE TO PULL SANDY BACK TOWARDS THE COAST...ESPECIALLY SINCE SHE IS
SLOWED BY MORE PRONOUNCED DOWNSTREAM BLOCKING. WHILE THE ECMWF
TROUGH LOOKS ALMOST TOO STRONG...WE HAVE SEEN ALREADY THIS SEASON
TWO -3/-4 SD 500MB TROUGHS DEVELOP...SO IT CANNOT BE RULED OUT HERE.
ADDITIONALLY...GUIDANCE HAS A TENDENCY TO BREAK DOWN RIDGES TOO
QUICKLY...WHICH WOULD FAVOR A TRACK AT LEAST SOMEWHAT WEST OF THE
CURRENT GFS SOLUTIONS. HOWEVER...ECMWF IS THE OUTLIER BEING SO FAR
WEST...AND THE GFS HAS SUPPORT FROM ALL OF ITS ENSEMBLES. NHC/HPC
CURRENTLY SUPPORT A TRACK SOMEWHERE BETWEEN THE TWO...CLOSE TO THE
CMC.

ONE THING APPEARS NEARLY CERTAIN...WARM WATER TEMPS AND GREAT 300MB
VENTILATION/COUPLED JET STRUCTURE (70 KT JETS ON BOTH SIDES OF THE
STORM) AS THE SYSTEM TRANSITIONS TO EXTRA-TROPICAL WILL SUPPORT A
VERY LARGE AND INTENSE CYCLONE...EVEN IF THE DIRECT EFFECTS
(WIND/RAIN) ARE MINIMAL IN THE LOCAL AREA. STILL...A CONSENSUS TRACK
WOULD BRING SOME ENHANCED NORTH WINDS AND AT LEAST SCHC OF
PRECIP...HIGHEST AT THE COAST...WHICH AGREES WITH CONTINUITY AND
WILL MAKE ONLY MINOR ADJUSTMENTS AT THIS TIME. LARGE SURF, STRONG
RIP CURRENTS, AND SOME COASTAL EROSION APPEAR LIKELY DUE TO SEVERAL
DAYS OF HIGH AMPLITUDE/LONG PERIOD SWELL COINCIDING WITH
ASTRONOMICAL HIGH TIDES NEXT WKND.
Member Since: August 19, 2006 Posts: 13 Comments: 14629
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They all going W now
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I see the Euro is still the stubborn outlier.
Is there anything else I've missed since yesterday?
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Not stacked.

000
URNT12 KNHC 231240
VORTEX DATA MESSAGE AL182012
A. 23/11:51:40Z
B. 13 deg 22 min N
077 deg 53 min W
C. 850 mb 1391 m
D. 22 kt
E. 307 deg 29 nm
F. 044 deg 24 kt
G. 307 deg 88 nm
H. 997 mb
I. 17 C / 1519 m
J. 20 C / 1519 m
K. 16 C / NA
L. NA
M. NA
N. 1345 / 8
O. 0.02 / 3 nm
P. AF301 0218A SANDY OB 08
MAX OUTBOUND AND MAX FL WIND 48 KT SE QUAD 12:18:30Z
Sfc cntr 340/12nm from flight level center. Flight level center up against convection
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580. JRRP
Quoting AussieStorm:

Why, cause they all pretty much have Sandy going over Jamaica?

Sandy is moving in the east part of the models
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579. HadesGodWyvern (Mod)


Depression in Arabian Sea near Socotra Island (Yemen)
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Quoting JRRP:
Interesting

Why, cause they all pretty much have Sandy going over Jamaica?
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Tornado Touches Down In Northern California, San Francisco Storms Tonight

A Tornado hit after 3:15pm PDT on Monday afternoon in Northern California, striking near Yuba City, or 40 miles north of Sacramento.

No injuries have been reported with the tornado. "We've had reports of power lines down and some outbuildings damaged," the weather service said. "Some kind of a small outbuilding was lifted about 200 feet from where it was located."



The storms came with a tornado warning as the tornado hit and several other funnel clouds were seen. The tornado (in the image above) was likely no stronger than an EF0-1.

"It was a weak tornado," said TheWeatherSpace.com Senior Meteorologist Kevin Martin. "HS readings were high in the area and the ingredients came together suddenly for this to happen. The dynamics really came together quickly."


Martin is saying thunderstorms will hit San Francisco tonight.

"Oh we know the big Giants game is happening, however late at night after the game we will be seeing late night thunderstorms and gusty conditions to boot across the San Francisco Bay area,"
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Sandy looks stronger than 40kt. Probably closer to 50kt.
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from facebook:

Sandy and the Fork in the Road
Posted by: bnorcross, 12:12 PM GMT on October 23, 2012

The forecast dilemma for Sandy continues as we look ahead to the weekend and beyond. For the next few days, the center of the strengthening tropical storm and likely hurricane will move north out of the Caribbean with direct, life-threatening impacts on Jamaica, eastern Cuba, Haiti, and the Dominican Republic tomorrow into Thursday. These islands all need to move to an alert status.

It also appears likely that much of the Bahamas will get flooding and high winds Friday into Saturday, similar to Hurricane Noel in 2007, with Florida feeling fringe effects, especially along the east coast.

Then things get murky, with the two groups of computer forecast models heading in different directions... two forks in the road. Both the American GFS and the European ECMWF show the jet stream dipping down from the north and beginning to affect the storm. The GFS affects it in the traditional sense of pushing it out to sea.

The European develops a jet-stream dip of VERY unusual shape and intensity, however, which wants to grab Sandy, inject significant energy into the system, and pull it north as a MEGA nor'easter.

This is an extremely unusual pattern which yields an extreme result, but it can't be totally discounted as a possibility. The European model has been the most accurate computer model for the last few years, though it has had some spectacular misses as well.

The upper-air disturbance that is forecast to turn into the jet-stream dip that grabs or doesn't grab Sandy is still developing off of western Canada... and there are a lot of pieces to fall into place. So for now our concern is for our friends in the northern Caribbean, but we watch for developments as the northern pattern develops over the next few days.

The fork comes around Saturday, so everybody from the Mid-Atlantic to the Northeast and well inland will need to pay close attention to developments.
Member Since: August 19, 2006 Posts: 13 Comments: 14629
125 mph cat 3...941 mb (could reach major status though)

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573. JRRP
Interesting
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Quoting TropicalAnalystwx13:

It's definitely difficult to get a storm to recurve in a negative NAO, but it doesn't mean that it won't.


Thanks TA!
Member Since: August 19, 2006 Posts: 13 Comments: 14629
Circulation seems to be somewhat more defined than last night, but Sandy still needs at least 12 hours before it can start the process of developing a respectable inner-core. If that can happen, there is some moderate instability and strong OHC to work with until this hit Cuba.

I will say that this system has the most favorable conditions to work with since Ernesto, if not all season.

Should be quite the sight to watch Sandy's wind field explode once it interact with the PV anomaly shooting down from Canada.
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Sfc. Press:996.8 mb
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Woah hello there
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Bye guys.

Member Since: July 6, 2010 Posts: 113 Comments: 31565
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: 31565

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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.