Sandy intensifying, headed towards Jamaica

By: Dr. Jeff Masters , 2:49 PM GMT on October 23, 2012

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Tropical Storm Sandy is on the move northwards towards Jamaica, and is slowly intensifying. The Hurricane Hunters are in the storm, and measured surface winds near 50 mph in the storm's northeast quadrant at 9 am EDT. The latest center fix, taken at 10:20 am EDT, found that Sandy's pressure had fallen 2 mb since early this morning, to 995 mb. Intermittent rain squalls from Sandy have been affecting Jamaica since Monday night, and Kingston, Jamaica has picked up 0.82" of rain from Sandy as of 9 am EDT. and Sandy is over very warm waters of 29.5°C, is in an unusually moist environment with relative humidities above 80%, and is experiencing light wind shear of 5 - 10 knots. These conditions are very favorable for intensification, and Sandy's heavy thunderstorms have increased in areal extent, intensity, and organization this morning, as seen on satellite loops.


Figure 1. Morning satellite image of Tropical Storm Sandy.

Sandy a potential threat to New England
Wind shear is forecast to be in the low to moderate range, 5 - 20 knots, through Thursday morning. This should allow continued development of Sandy, and rapid development is possible. The 8 am EDT SHIPS model forecast predicted a 62% chance that Sandy's winds would increase by 30 mph over a 24-hour period. However, the Hurricane Hunters found this morning that the center at 5,000 feet was displaced 7 miles from the surface center, and there was no indication that Sandy was building an eyewall, so I expect that the earliest Sandy could become a hurricane is Wednesday morning. The 5 am EDT NHC Wind Probability Forecast gave a 49% chance that Sandy would 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 and the storm will have to cross the rugged terrain of Cuba, which should weaken Sandy's winds by 20 - 30 mph. By Friday, Sandy should be over warm waters in the Central Bahamas, but only modest re-intensification by 10 - 20 mph should occur, due to high wind shear. At that point, a very complicated meteorological situation unfolds, as Sandy interacts with a trough of low pressure approaching the U.S. East Coast. The trough may steer Sandy northeastwards, out to sea, as predicted by the GFS, HWRF, and GFDL models. However, an alternative solution, shown by the ECMWF and NOGAPS models, is for the trough to inject a large amount of energy into Sandy, converting it to a powerful subtropical storm that hits New England early next week with a central pressure of 948 mb and winds near hurricane-force. The ECMWF and NOGAPS models are off by a full day in their predictions of when the storm would arrive, with the 06Z NOGAPS model predicting Sandy's heavy rains will arrive on North Carolina's Outer Banks on Sunday, then spread into the mid-Atlantic and New England on Sunday. The 00Z ECMWF model forecast predicts that Sandy will arrive in New England on Monday night. Stay tuned.


Figure 2. The Tuesday morning 06Z (2 am EDT) run of the GFS model was done 20 times at lower resolution with slightly varying initial conditions of temperature, pressure, and moisture to generate an ensemble of forecast tracks for Sandy (pink lines). These forecasts show substantial uncertainty in Sandy's path after Friday, with the majority of the forecasts taking Sandy to the northeast, out to sea, but a substantial number predicting a landfall in the Northeast or mid-Atlantic states of the U.S. The white line shows the official GFS forecast, run at higher resolution.


Figure 3. Morning satellite image of Tropical Depression Nineteen.

Tropical Depression Nineteen in the middle Atlantic
There has been little change to Tropical Depression Nineteen since it formed Monday in the middle Atlantic. TD 19 has a modest area of heavy thunderstorms, as seen on visible satellite images, and dry air from an upper-level low pressure system on its west side is slowing development. TD 19 is moving north-northeast at 15 mph, and has moved over waters that are 27°C, a full degree cooler what the storm had to work with on Monday. Wind shear is a moderate 10 - 20 knots, but is forecast to increase to the high range, 20 - 40 knots, on Wednesday. Ocean temperatures will drop below 26°C on Wednesday, so TD 19 has until Wednesday morning to get its act together and develop into Tropical Storm Tony. TD 19 will not threaten any land areas, and will likely be dead by Friday.


Video 1. Impressive weather video of the week: Baseball-sized hail splashing into a swimming pool during a hailstorm in South Africa on Saturday, October 20, 2012. The action gets interesting at about 1 minute into the video.

Tonight (October 23), PBS Frontline airs "Climate of Doubt", which examines the politics of climate change, and how a once generally accepted fact--that humans have contributed to, if not caused, global warming--has been dismissed by many politicians. It's on at 10 pm here in Michigan, but times may vary, depending upon the station.

Jeff Masters

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889. Grothar
12:44 AM GMT on October 24, 2012
Don't pay attention to the models on Sandy, they are old, but look at where they are moving 90L.

Member Since: July 17, 2009 Posts: 69 Comments: 25517
888. Stormchaser2007
12:43 AM GMT on October 24, 2012
00
URNT12 KNHC 240035
VORTEX DATA MESSAGE AL182012
A. 24/00:09:40Z
B. 14 deg 44 min N
077 deg 10 min W
C. 850 mb 1339 m
D. 39 kt
E. 305 deg 29 nm
F. 065 deg 40 kt
G. 312 deg 41 nm
H. 991 mb
I. 16 C / 1519 m
J. 20 C / 1519 m
K. NA / NA
L. Ragged Eye
M. C32
N. 12345 / 8
O. 0.02 / 4 nm
P. AF302 0318A SANDY OB 10
MAX OUTBOUND AND MAX FL WIND 57 KT SE QUAD 00:25:00Z
Additoinal spiral band 20nm dia in eye
;

Member Since: June 9, 2007 Posts: 4 Comments: 15790
887. AussieStorm
12:41 AM GMT on October 24, 2012
Quoting Neapolitan:
The full line:

AL, 19, 2012102400, , BEST, 0, 264N, 498W, 35, 1004, TS, 34, NEQ, 40, 40, 0, 0, 1010, 200, 40, 0, 0, L, 0, , 0, 0, TONY, M,

Of course I'll wait for the NHC to take there time on naming TD19 TS Tony, it's been a TS for almost 24hrs now.
Member Since: September 30, 2007 Posts: 9 Comments: 15932
886. MAweatherboy1
12:41 AM GMT on October 24, 2012
L. Eye Character (Undecoded): Ragged Eye
M. Eye Shape & Diameter: Circular with a diameter of 32 nautical miles (37 statute miles)
Member Since: February 11, 2012 Posts: 82 Comments: 7640
885. TropicalAnalystwx13
12:40 AM GMT on October 24, 2012
Lots of 55 knot flight-level winds.
Member Since: July 6, 2010 Posts: 113 Comments: 31575
884. kimoskee
12:40 AM GMT on October 24, 2012
Of concern is the fact that we are accustomed to storms approaching from the east and not south in Kingston.

Don't have the mountains to protect us this time.

Member Since: August 17, 2008 Posts: 0 Comments: 672
883. HurrikanEB
12:40 AM GMT on October 24, 2012
I like how this morning's GFS ensemble members have her anywhere from Toronto to Spain.....


Member Since: May 2, 2008 Posts: 12 Comments: 1306
882. NCHurricane2009
12:39 AM GMT on October 24, 2012
Quoting Neapolitan:
The full line:

AL, 19, 2012102400, , BEST, 0, 264N, 498W, 35, 1004, TS, 34, NEQ, 40, 40, 0, 0, 1010, 200, 40, 0, 0, L, 0, , 0, 0, TONY, M,

Elllooooooo Tony!

Only 2 letters stand between us and the Greek alphabet...never thought I'd say that after 2005. But its happened again in 2010 and now 2012....wow...
Member Since: September 15, 2009 Posts: 448 Comments: 3623
881. AussieStorm
12:39 AM GMT on October 24, 2012
Quoting evilpenguinshan:
right, but the pressures (and thus surge levels) were in Cat 3 territory. remember all the hullabaloo about adjusting the scale after that? it's a legitimate concern.

Yeah I know, I was also talking about a new scale. But the fact is Tropical Cyclones are judged on wind speed and not storm surge or surface pressure.
Member Since: September 30, 2007 Posts: 9 Comments: 15932
880. Tropicsweatherpr
12:38 AM GMT on October 24, 2012
Quoting MAweatherboy1:
Still no impressive winds in the new data set. 51mph was the highest 1 minute reading with rain rates under .75 inches per hour.


Plane has not gone to the East and NE quads.
Member Since: April 29, 2009 Posts: 75 Comments: 14076
879. Tazmanian
12:38 AM GMT on October 24, 2012
Quoting TropicalAnalystwx13:
Three straight years with the third highest amount of named storms in a season on record.



so marh for EL nino lol
Member Since: May 21, 2006 Posts: 5091 Comments: 114783
878. evilpenguinshan
12:37 AM GMT on October 24, 2012
thank you much.

look at all those greens on the Funktop tonight. gonna be a long night tonight with all the F5'ing on the imagery =D



Quoting Stormchaser2007:


2232 Zulu was when the pass was completed.
Member Since: March 20, 2012 Posts: 0 Comments: 506
877. NCHurricane2009
12:36 AM GMT on October 24, 2012
Quoting ProgressivePulse:
I leave you with the models converging on the NHC track.


That means the GFS has been the better horse to bet on this year...Euro maybe old news....
Member Since: September 15, 2009 Posts: 448 Comments: 3623
876. TropicalAnalystwx13
12:36 AM GMT on October 24, 2012
Three straight years with the third highest amount of named storms in a season on record.
Member Since: July 6, 2010 Posts: 113 Comments: 31575
875. Neapolitan
12:35 AM GMT on October 24, 2012
The full line:

AL, 19, 2012102400, , BEST, 0, 264N, 498W, 35, 1004, TS, 34, NEQ, 40, 40, 0, 0, 1010, 200, 40, 0, 0, L, 0, , 0, 0, TONY, M,
Member Since: November 8, 2009 Posts: 4 Comments: 13473
874. AussieStorm
12:35 AM GMT on October 24, 2012
Member Since: September 30, 2007 Posts: 9 Comments: 15932
873. padirescu
12:35 AM GMT on October 24, 2012
Quoting evilpenguinshan:
right, but the pressures (and thus surge levels) were in Cat 3 territory. remember all the hullabaloo about adjusting the scale after that? it's a legitimate concern.


Some of us in the western communities of West Palm Beach were also flooded for 5 days due to Isaac's rainbands the day after it passed the keys.
Member Since: September 2, 2008 Posts: 0 Comments: 57
872. SFLWeatherman
12:35 AM GMT on October 24, 2012
Member Since: May 23, 2012 Posts: 0 Comments: 4424
871. MAweatherboy1
12:34 AM GMT on October 24, 2012
Still no impressive winds in the new data set. 51mph was the highest 1 minute reading with rain rates under .75 inches per hour.
Member Since: February 11, 2012 Posts: 82 Comments: 7640
870. kimoskee
12:33 AM GMT on October 24, 2012
Quoting kmanhurricaneman:
worried for the portmoore area kimoskee


They usually have flooding problems. :-(
Member Since: August 17, 2008 Posts: 0 Comments: 672
869. CaicosRetiredSailor
12:33 AM GMT on October 24, 2012


Member Since: July 12, 2007 Posts: 0 Comments: 5999
868. ProgressivePulse
12:33 AM GMT on October 24, 2012
Or was it the NHC converging on the models track?

I think a lil of both..
Member Since: August 19, 2005 Posts: 5 Comments: 5045
867. Stormchaser2007
12:33 AM GMT on October 24, 2012
Quoting evilpenguinshan:
whoa.

how exactly does one read that timestamp, though? i'm confused as to when it is supposed to be...



2232 Zulu was when the pass was completed.
Member Since: June 9, 2007 Posts: 4 Comments: 15790
866. GeoffreyWPB
12:32 AM GMT on October 24, 2012
Sleep well Largo...You are going to be busy tomorrow.
Member Since: September 10, 2007 Posts: 0 Comments: 11012
865. ProgressivePulse
12:32 AM GMT on October 24, 2012
I leave you with the models converging on the NHC track.

Member Since: August 19, 2005 Posts: 5 Comments: 5045
864. SFLWeatherman
12:32 AM GMT on October 24, 2012
Rain off and on all day for me!
Member Since: May 23, 2012 Posts: 0 Comments: 4424
863. Thing342
12:32 AM GMT on October 24, 2012
Considering that this storm has a nearly-complete eyewall and a 991mb pressure, I think that it is at least 60 mph.
Member Since: August 1, 2012 Posts: 0 Comments: 436
862. LargoFl
12:32 AM GMT on October 24, 2012
Quoting GeoffreyWPB:
Largo...You are on overdrive tonight..huh...:)
LOL yeah, my eyes are tired..think im going to call it a night, hope everyone on the islands get thru this safe..have a great night folks..tomorrow should be quite interesting LOL...nite all
Member Since: August 6, 2011 Posts: 4 Comments: 37103
861. Neapolitan
12:31 AM GMT on October 24, 2012
AL, 19, 2012102400, , BEST, 0, 264N, 498W, 35, 1005, TS, 34, NEQ, 40, 40, 0, 0, 1010, 200, 60, 0, 0,
Member Since: November 8, 2009 Posts: 4 Comments: 13473
860. NCHurricane2009
12:31 AM GMT on October 24, 2012
Quoting 954FtLCane:


Good choice!!! Now that is intensification music if I've ever heard it!!

Too bad techno like that doesn't end up TWC's Local on the 8s....
Member Since: September 15, 2009 Posts: 448 Comments: 3623
859. MAweatherboy1
12:30 AM GMT on October 24, 2012
Quoting MAweatherboy1:
I think the NHC will pull the trigger and give us Tony at 11.

23/2345 UTC 26.5N 49.8W T2.5/2.5 19L -- Atlantic

Actually I know they will now.

AL, 19, 2012102400, , BEST, 0, 264N, 498W, 35, 1005, TS
Member Since: February 11, 2012 Posts: 82 Comments: 7640
858. kimoskee
12:30 AM GMT on October 24, 2012
Kingston, Jamaica. Kingston Airport closes as of 10pm tonight and Mobay airport closes tomorrow (Wednesday)
Member Since: August 17, 2008 Posts: 0 Comments: 672
857. evilpenguinshan
12:30 AM GMT on October 24, 2012
whoa.

how exactly does one read that timestamp, though? i'm confused as to when it is supposed to be...

Quoting Stormchaser2007:


Member Since: March 20, 2012 Posts: 0 Comments: 506
856. MAweatherboy1
12:30 AM GMT on October 24, 2012
I think the NHC will pull the trigger and give us Tony at 11.

23/2345 UTC 26.5N 49.8W T2.5/2.5 19L -- Atlantic
Member Since: February 11, 2012 Posts: 82 Comments: 7640
855. ProgressivePulse
12:29 AM GMT on October 24, 2012
And of course it updates just as I post it, lol. Looks much better now, lol.

Member Since: August 19, 2005 Posts: 5 Comments: 5045
854. kmanhurricaneman
12:28 AM GMT on October 24, 2012
worried for the portmoore area kimoskee
Member Since: August 14, 2008 Posts: 0 Comments: 1002
853. GeoffreyWPB
12:28 AM GMT on October 24, 2012
Largo...You are on overdrive tonight..huh...:)
Member Since: September 10, 2007 Posts: 0 Comments: 11012
852. Stormchaser2007
12:27 AM GMT on October 24, 2012
Quoting TropicalAnalystwx13:
Well that can't be good.



Member Since: June 9, 2007 Posts: 4 Comments: 15790
851. ProgressivePulse
12:27 AM GMT on October 24, 2012
.
Member Since: August 19, 2005 Posts: 5 Comments: 5045
Member Since: August 6, 2011 Posts: 4 Comments: 37103
Quoting kimoskee:
Kingston, Jamaica.

Curfew orders issued in strategic locations island-wide. ODPEM moving to level 2 at 10pm.
Certain flood prone areas have recommended evacuation orders.
Pedro Cays evacuated.
PM Simpson-Miller expected back on island tonight (she was in Canada on official visit).
Member Since: August 14, 2008 Posts: 0 Comments: 1002
Quoting LostTomorrows:


I'm going to tell my friend in Bermuda, and she's going to be mad at you.
LOL, im sorry hahaha
Member Since: August 6, 2011 Posts: 4 Comments: 37103
Down to 990mbs

Member Since: June 9, 2007 Posts: 4 Comments: 15790
The 18z GFDL has finished running. End of the run at 126 hours:

Member Since: February 11, 2012 Posts: 82 Comments: 7640
Winds died off as they hit the center, down to 14mph with the lowest pressure. Nothing special with the winds yet, though I'm certain they're around there somewhere.
Member Since: July 8, 2005 Posts: 259 Comments: 23641
Quoting caneswatch:
WPTV showing the Tropical Storm-force wind field affecting South Florida, Treasure Coast, and Brevard if i'm not mistaken.


Hey buddy...I'm more concerned about the rainfall amounts than the wind. Will it be right or left loaded?
Member Since: September 10, 2007 Posts: 0 Comments: 11012
Quoting caneswatch:
WPTV showing the Tropical Storm-force wind field affecting South Florida, Treasure Coast, and Brevard if i'm not mistaken.



More than likely you will see TS watches go up for the immediate coastal areas from Juptier Inlet Southward tonight at 11.
Member Since: August 19, 2005 Posts: 5 Comments: 5045
Time: 00:09:30Z
Coordinates: 14.7333N 77.1667W
Acft. Static Air Press: 843.0 mb (~ 24.89 inHg)
Acft. Geopotential Hgt: 1,408 meters (~ 4,619 feet)
Extrap. Sfc. Press: 990.8 mb (~ 29.26 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 249° at 24 knots (From the WSW at ~ 27.6 mph)
Air Temp: 19.3°C (~ 66.7°F)
Dew Pt: 8.3°C (~ 46.9°F)
Peak (10s) Flt. Lvl. Wind: 27 knots (~ 31.0 mph)
SFMR Peak (10s) Sfc. Wind: 19 knots (~ 21.8 mph)
SFMR Rain Rate: 4 mm/hr (~ 0.16 in/hr)
(*) Denotes suspect data

Probably the center.
Member Since: Posts: Comments:
Kingston, Jamaica.

Curfew orders issued in strategic locations island-wide. ODPEM moving to level 2 at 10pm.
Certain flood prone areas have recommended evacuation orders.
Pedro Cays evacuated.
PM Simpson-Miller expected back on island tonight (she was in Canada on official visit).
Member Since: August 17, 2008 Posts: 0 Comments: 672
right, but the pressures (and thus surge levels) were in Cat 3 territory. remember all the hullabaloo about adjusting the scale after that? it's a legitimate concern.
Quoting AussieStorm:

Why not, Isaac had only Cat 1 winds, no Cat 2 winds were found.
Member Since: March 20, 2012 Posts: 0 Comments: 506
839. JLPR2
Quoting NCHurricane2009:




I want some Frosted Flakes...


They're Grrrrreat!
Member Since: Posts: Comments:

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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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