Tropical Depression 18 forms south of Jamaica

By: Dr. Jeff Masters , 3:34 PM GMT on October 22, 2012

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Tropical Depression Eighteen is here, and appears poised to become Tropical Storm Sandy by early Tuesday morning. TD 18 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 TD 18's heavy thunderstorms are steadily organizing into curved spiral bands, as seen on visible satellite loops. An Air Force hurricane hunter aircraft will investigate TD 18 this afternoon.


Figure 1. Morning satellite image of Tropical Depression Eighteen.

Forecast for TD 18
Wind shear is forecast to be in the low to moderate range, 5 - 20 knots, through Tuesday night. This should allow for some steady development of TD 18. On Tuesday, a trough of low pressure to the north is expected to pull TD 18 to the north-northeast, which should put the storm in the vicinity of Jamaica on Wednesday and Eastern Cuba on Thursday. The 11 am EDT NHC Wind Probability Forecast gives a 32% chance that TD 18 will be a hurricane by 8 am EDT Wednesday, when the center should be close to Jamaica. Wind shear will rise to a high 25 - 30 knots by Thursday, which should make it difficult for TD 18 to intensify. By Friday, TD 18 should be in the Central or Eastern Bahamas, and wind shear may increase further, making TD 18 more of a hybrid subtropical storm. It is unclear at this point whether or not the trough pulling TD 18 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 TD 18 and force the storm to the west-northwest, with a potential threat to the Northwestern Bahamas and U.S. East Coast by Saturday, as predicted by the ECMWF model. TD 18 will be capable of bringing heavy rains of 5 - 10 inches, with isolated amounts of up to 15 inches in mountainous areas, to Jamaica and Haiti, Monday night through Thursday. Heavy rains will begin on Tuesday in Eastern Cuba, and spread northwards into the Central and Eastern Bahamas by Wednesday. Heavy rains of 3 - 6 inches can be expected in the Cayman Islands and Dominican Republic, Tuesday through Thursday.

Invest 90L in the middle Atlantic
A small low pressure system (Invest 90L) about 700 miles east-northeast of the northernmost Lesser Antilles Islands is headed northward at about 10 mph. The disturbance has a modest area of heavy thunderstorms, as seen on visible satellite images, and is struggling with cool, dry air from the upper-level low pressure system that it is trying to form underneath. This upper-level low has provided 90L the spin it needs to become a tropical cyclone, though. Wind shear is a moderate 10 - 20 knots, and is forecast to remain in the moderate range until Wednesday morning. This may allow 90L to develop into a tropical cyclone before it encounters high wind shear of 20 - 30 knots on Wednesday. It's unlikely that 90L will affect any land areas. In their 8 am EDT tropical weather outlook, NHC gave 90L a 50% chance of developing into a tropical cyclone by Wednesday morning.

Jeff Masters

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464. Skyepony (Mod)
Quoting TropicalAnalystwx13:

We've had four already (Oscar, Patty, Rafael, Sandy). Tropical Depression Nineteen should make it five tonight.


Thanks! Has been a busy blur..
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My own official 2012 hurricane season forecast that I've kept secret until now calls for 21 named storms!!
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I'm a little surprised how quickly the spin got going.
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i think in NOV we could see 2 name storms
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459. WunderAlertBot (Admin)
JeffMasters has created a new entry.
Quoting Skyepony:


I think I went with 19 or 20. Didn't buy an official El Nino.

Had minimum of 3, probilby more for Oct. There is 3.. 4 is looking probable.

We've had four already (Oscar, Patty, Rafael, Sandy). Tropical Depression Nineteen should make it five tonight.
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457. Skyepony (Mod)
Quoting TropicalAnalystwx13:

Most everybody did. And the ones that didn't did not even forecast to be as active as it has been.


I think I went with 19 or 20. Didn't buy an official El Nino.

Had minimum of 3, probilby more for Oct. There is 3.. 4 is looking probable.
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456. HadesGodWyvern (Mod)
Philippines Atmospheric Geophysical Astronomical Services and Administration
Tropical Cyclone Advisory #2
TROPICAL DEPRESSION OFEL
5:00 AM PhST, October 23 2012
==============================

Tropical Depression "OFEL" has maintained its strength as it moves west towards northern Mindanao-eastern Visayas Area

At 4:00 AM PhST, Tropical Depression Ofel [1000 hPa] located at 9.4°N 130.1°E or 460 km east of Surigao City, Surigao Del Sur has 10 minute sustained winds of 30 knots. The depression is reported as moving west at 7 knots.

Signal Warnings
=================

Signal Warning #1
----------------

Visayas Region
=============
1. Leyte
2. Southern Leyte
3. Eastern Samar
4. Western Samar

Mindanao Region
--------------
1. Surigao Del Norte
2. Dinagat Island
3. Surigao Del Sur
4. Agusan Provinces
5. Camiguin Island


Additional Information
=========================

Residents living in low lying and mountainous areas under public storm warning signal #1 are alerted against possible flash floods and landslides.

Estimated rainfall amount is from 5-20 mm per hour (moderate to intense) within the 400 km diameter of the tropical depression.

Fishing boats and other small seacrafts are advised not to venture out into the eastern seaboards of southern Luzon, Visayas and Mindanao due to Tropical Depression "OFEL" and the northeast Monsoon.

The public and the disaster coordinating councils concerned are advised to take appropriate actions and watch for the next bulletin to be issued at 11 AM today.
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Quoting TropicalAnalystwx13:

Most everybody did. And the ones that didn't did not even forecast to be as active as it has been.
I predict 16 name storms but I never thought 18 may get 19 soon with TD 19 strengthening into Tony.
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Here is an interesting story on TS Sandy, looking at a possible worst-case scenario:
Grim Storm Scenarios Loom for Mid-Atlantic, Northeast
October 22nd, 2012, By Andrew Freedman

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Quoting PalmBeachWeather:
Even though September 10th is considered the peak day of the season, I vote for the middle and end of October for Florida..
Never to forget Wilma
Member Since: October 3, 2008 Posts: 0 Comments: 5940
In 24 hours from this:



To this:



Just a wee bit of organization there.
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Quoting ncstorm:
too much going on in the Atlantic..unreal

Even though September 10th is considered the peak day of the season, I vote for the middle and end of October for Florida..
Member Since: October 3, 2008 Posts: 0 Comments: 5940
Quoting TropicalAnalystwx13:

Most everybody did. And the ones that didn't did not even forecast to be as active as it has been.


I don't think anyone could have predicted this year would have 18 named storms and 9 hurricanes. The one major hurricane though..
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Quoting ncstorm:
and to think NOAA predicted a below average hurricane season due to El Nino..

Most everybody did. And the ones that didn't did not even forecast to be as active as it has been.
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too much going on in the Atlantic..unreal

Member Since: August 19, 2006 Posts: 13 Comments: 16083
This caught my eye in the discussion, I had a feeling we might be dealing with this.
THE AIR FORCE HURRICANE HUNTERS FOUND A BAND OF SURFACE WINDS NEAR
35 KT OVER THE SOUTHEASTERN QUADRANT OF THE CYCLONE...SO THE SYSTEM
IS BEING NAMED AT THIS TIME. THE ENVIRONMENT SHOULD BE
CHARACTERIZED BY WEAK SHEAR...AND THE STORM WILL BE OVER WARM
WATERS...FOR THE NEXT COUPLE OF DAYS SO ADDITIONAL STRENGTHENING IS
LIKELY. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
FORECAST AND CLOSE TO THE MODEL CONSENSUS. THIS COULD BE
CONSERVATIVE...HOWEVER...AS THE RAPID INTENSIFICATION INDEX SHOWS A
SIGNIFICANT POSSIBILITY OF RAPID STRENGTHENING DURING THE NEXT DAY
OR SO.
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Quoting ncstorm:
and to think NOAA predicted a below average hurricane season due to El Nino..



oops
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and to think NOAA predicted a below average hurricane season due to El Nino..
Member Since: August 19, 2006 Posts: 13 Comments: 16083
No doubt we've got an organizing tropical storm on our hands. Also, the minimum pressure recorded was displaced 12NM from the center, according to the vortex. That means there is some disorganization of the core, but no were near as bad as it could be.
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I think the NHC has their forcast too low. It looks like it is really organizing. I do kind of want it to come my way to mabye shed a day or two off school but not another one like irene. Pffft. servpro
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Quoting floridafisherman:


so you have changed your september forecast when you called the season over and now think there will be more storms? just curious on why you changed your position so radically



1st off none of your bee WAX 2nd you been reported
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Quoting trHUrrIXC5MMX:

Tropical Storm SANDY Forecast Discussion

Home Public Adv Fcst Adv Discussion Wind Probs Graphics Archive

000
WTNT43 KNHC 222101
TCDAT3

TROPICAL STORM SANDY DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012
500 PM EDT MON OCT 22 2012

THE AIR FORCE HURRICANE HUNTERS FOUND A BAND OF SURFACE WINDS NEAR
35 KT OVER THE SOUTHEASTERN QUADRANT OF THE CYCLONE...SO THE SYSTEM
IS BEING NAMED AT THIS TIME. THE ENVIRONMENT SHOULD BE
CHARACTERIZED BY WEAK SHEAR...AND THE STORM WILL BE OVER WARM
WATERS...FOR THE NEXT COUPLE OF DAYS SO ADDITIONAL STRENGTHENING IS
LIKELY. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
FORECAST AND CLOSE TO THE MODEL CONSENSUS. THIS COULD BE
CONSERVATIVE...HOWEVER...AS THE RAPID INTENSIFICATION INDEX SHOWS A
SIGNIFICANT POSSIBILITY OF RAPID STRENGTHENING DURING THE NEXT DAY
OR SO.


Yes, I hate to say that it looks like it would like to do a WPac. it was looking so dogged last night and then today, what a change...and is just looking ominous to me
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Quoting CybrTeddy:


Several sustained winds of 50mph, non contaminated.

snady intensifiying more than expected.....
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hi y'all
i see that we have sandy and td 19(future ts tony)
dang,we might just go exhaustion
title for the season is....
2012,the little season that could loll
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Quoting TropicalAnalystwx13:

Based on what?


Several sustained winds of 50mph, non contaminated.
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How this season currently stands...

Total depressions: 19
Total storms: 18
Total hurricanes: 9
Total majors: 1

Total Accumulated Cyclone Energy: 107.855 units
Storm with highest ACE: Nadine - 25.6 units
Storm with lowest ACE: Sandy - 0.1225 (Joyce/Helene - 0.2450)

May: 2-0-0
June: 2-1-0
July: 0-0-0
August: 8 (record)-4-0
September: 2-2-1
October: 4-1-0
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I would love to listen to one of those calls..

NWS, Wilmington, NC

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...THE LONG TERM STARTS OUT WITH VERY PLEASANT
WEATHER WITH HIGH PRESSURE EXTENDING INTO THE CAROLINAS FROM THE
NORTHEAST. MEANWHILE AN UPPER LEVEL RIDGE BUILDS ALONG THE EAST
COAST. MUCH OF THE EASTERN U.S. WILL BE EXPERIENCING NEARLY FULL
SUNSHINE AND UNSEASONABLY WARM TEMPERATURES. EVEN LOCALLY THIS SEEMS
LIKELY TO BE THE CASE THROUGH FRIDAY.

AT THE SAME TIME HOWEVER SOME THINGS WILL BE TAKING SHAPE THAT COULD
POTENTIALLY HAVE A TREMENDOUS IMPACT ON EAST COAST WEATHER TOWARDS
THE END OF THE PERIOD. ONE WILL BE THE YET TO DEVELOP BUT PROBABLY
SOON TO BE NAMED TROPICAL STORM SANDY LIFTING NORTH OUT OF THE
CARIBBEAN. THE OTHER BIG PLAYER WILL BE THE DEEP TROUGH AND LEADING
COLD FRONT SINKING SOUTH AND EASTWARD ACROSS THE CENTRAL U.S. THE
DEGREE TO WHICH THE TWO INTERACT IS BOTH HIGHLY UNCERTAIN AND OF
INCREASING POTENTIAL SIGNIFICANCE TO INTERESTS ALONG THE EAST COAST.
AS INTERESTING AS SOME OF THE POSSIBILITIES ARE FURTHER TO THE NORTH
THE POTENTIAL LOCAL EFFECTS ARE SIMILARLY UNCERTAIN ALTHOUGH NOT SO
EXTREME. A FASTER/MORE AGGRESSIVELY DIGGING UPPER TROUGH WILL SOONER
CAPTURE THE TROPICAL SYSTEM AND BRING IT CLOSER TO THE CAROLINA
COAST OVER THE WEEKEND BRINGING INCREASED WINDS AND MAYBE EVEN SOME
RAINFALL. THE BIGGEST IMPACT STILL SEEMS MORE LIKELY TO BE SOME
DANGEROUS SURF/RIP CURRENTS. A SLOWER/LAZIER UPPER TROUGH TO THE
WEST WILL MEAN A MUCH FURTHER EAST TRACK AND CONFINE LOCAL EFFECTS
TO THE WAVES AND RIPS. THE LONG RANGE CONFERENCE CALL BETWEEN HPC
AND NHC FAVORED THE MORE WESTERN SOLUTIONS.
AS SUCH HAVE ONCE AGAIN
RAISED THE WEEKEND WIND FORECAST BUT HAVE KEPT RAIN CHANCES CAPPED
AT SLIGHT.
Member Since: August 19, 2006 Posts: 13 Comments: 16083
I would like to hear from Dr. Masters
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Quoting stormpetrol:
If the center makes it to 80-81W, The Caymans and Florida could be in play.


yes so true and something tells me that we will see a few more cones shifts to the W stormpetrol we need tokeep a close eye on this one
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Quoting PalmBeachWeather:
Cruel


yeah...That was not nice.
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Interesting year to say the least; 18th storm of the Atlantic Season in mid-October and right in line with the general formation location and track direction we normally see in October storms based on climatology. Could well skirt the US East Coast in the coming week depending on the ridging set-up but Jamaica is first in line.

Here's hoping that it will remain as a tropical storm for the duration with minimal impacts for everyone concerned.
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Brand new discussion from the National Weather Service in Taunton, MA.

SUNDAY AND MONDAY...

A VERY LOW CONFIDENCE FORECAST OVER THIS TIME PERIOD AND BEYOND.
TROPICAL STORM SANDY HAS DEVELOPED EARLY THIS EVENING ACROSS THE
CARIBBEAN. SANDY WILL TRACK VERY SLOWLY NORTH FOR THE REST OF THIS
WEEK. MEANWHILE...BY EARLY NEXT WEEK AN UPPER LEVEL TROUGH AND COLD
FRONT WILL BE APPROACHING SOUTHERN NEW ENGLAND.

THE MAIN QUESTION WILL BE IN REGARDS TO TIMING OF THE UPPER TROUGH
AND WHETHER OR NOT PHASING OCCURS WITH THE TROPICAL/HYBRID SYSTEM.
IT APPEARS THAT THE MAIN POTENTIAL WOULD BE BETWEEN NEXT MONDAY
THROUGH WEDNESDAY. THAT WOULD DEPEND ON PHASING AND IF THE TRACK IS
CLOSE ENOUGH TO OUR REGION. IF AND ONLY IF ALL THE POTENTIAL
INGREDIENTS COME TOGETHER A SIGNIFICANT TROPICAL/HYBRID SYSTEM WOULD
AFFECT OUR REGION. KEEP IN MIND...THIS POTENTIAL SYSTEM IS 7 TO 9
DAYS IN THE FUTURE. CONFIDENCE IS EXTREMELY LOW AND A SYSTEM
PASSING HARMLESSLY OUT TO SEA IS A VERY REAL POSSIBILITY AS WELL.
THE MAIN REASON WE DO NOT ISSUE HEADLINES MUCH MORE THAN 48 HOURS IN
ADVANCE IS BECAUSE TRACK ERRORS REMAIN TOO LARGE. WE ARE CURRENTLY
TALKING ABOUT A POTENTIAL STORM THAT IS A WEEK OR EVEN LONGER AWAY
FROM OUR AFFECTING OUR REGION. THERE CERTAINLY IS POTENTIAL FOR A
SIGNIFICANT SYSTEM...BUT WE ARE AND WILL REMAIN OUTSIDE THE TIME
RANGE FOR AT LEAST SEVERAL MORE DAYS TO HAVE MUCH CONFIDENCE IN ANY
SOLUTION.

WHAT WE DO KNOW IS THAT A COLD FRONT AND UPPER LEVEL TROUGH WILL BE
APPROACHING OUR REGION FROM THE WEST. WE MAY SEE SOME SHOWERS
DEVELOP SUNDAY AND/OR MONDAY AHEAD OF AND ALONG THE FRONT SO
INCLUDED SOME CHANCE POPS.
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429. Skyepony (Mod)
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 22nd day of the month at 21:14Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 301)
Mission Purpose: Investigate fourth suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 14
A. Time of Center Fix: 22nd day of the month at 20:35:30Z
B. Center Fix Coordinates: 12°26'N 78°19'W (12.4333N 78.3167W)
B. Center Fix Location: 235 miles (378 km) to the NW (307°) from Cartagena, Colombia.
C. Minimum Height at Standard Level: Not Available
D. Estimated (by SFMR or visually) Maximum Surface Wind: 39kts (~ 44.9mph)
E. Location of the Estimated Maximum Surface Wind: 37 nautical miles (43 statute miles) to the ENE (77°) of center fix
F. Maximum Flight Level Wind Inbound: From 165° at 42kts (From the SSE at ~ 48.3mph)
G. Location of Maximum Flight Level Wind Inbound: 37 nautical miles (43 statute miles) to the ENE (71°) of center fix
H. Minimum Sea Level Pressure: 1001mb (29.56 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 22°C (72°F) at a pressure alt. of 446m (1,463ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 24°C (75°F) at a pressure alt. of 444m (1,457ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 22°C (72°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration and Wind
N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 1,500 feet
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 5 nautical miles
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 42kts (~ 48.3mph) in the east quadrant at 20:20:30Z
Sea Level Pressure Extrapolation From: Below 1,500 feet
Maximum Flight Level Temp: 25°C (77°F) which was observed 10 nautical miles (12 statute miles) to the NNE (28°) from the flight level center
Remarks Section - Additional Remarks...
MIN SLP 999MB DISPLACED FROM WIND CTR 045/12NM
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Quoting floridafisherman:


so you have changed your september forecast when you called the season over and now think there will be more storms? just curious on why you changed your position so radically
Cruel
Member Since: October 3, 2008 Posts: 0 Comments: 5940
Afternoon everyone. Sandy is starting to fill out.

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Quoting floridafisherman:


so you have changed your september forecast when you called the season over and now think there will be more storms? just curious on why you changed your position so radically


do you track people down...stalker?
lol

well. no that many people though we could make it this far... I was one of them
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It's hard to imagine a Halloween storm in 2012 being tricky to navigate.





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Quoting Dakster:
TAz - I was thinking of a different picture of Sandy Cheeks... Ones that you might find on a beach.



oh
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Quoting Wunderwood:


On what info do you base your statement?
recon observations and wind info from recon
Member Since: July 14, 2009 Posts: 0 Comments: 3029
Not to get ahead of ourselves, but IF the European model is to be trusted with a landfall pressure at 926 mb it would surely be one of the most intense Nor'easter's in recorded history. To put it into perspective "The Storm of the Century" was 960 mb, and Katrina had the 3rd lowest pressure making landfall at 920 mb.

Does anyone have thoughts on the kind of impact / damage something like this could cause? Is there a way to prepare for something of this magnitude? TIA
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Quoting Tazmanian:
will now if TD 18 be comes the S storm and TD 19 be comes the T storm i think that would mark the 3rd or 4th time in a row we had 19 name storms in a season


dos any one still think this sesson is a bust ???



all so we still have nov and i think we could see one or two more name storms


so you have changed your september forecast when you called the season over and now think there will be more storms? just curious on why you changed your position so radically
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TAz - I was thinking of a different picture of Sandy Cheeks... Ones that you might find on a beach.
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2012 is now the 4th most active on record...should TD19 becomes TS Tony then it will join 2010, 2011 and 1887 for the third place.

IF ANOTHER ONE FORMS...Valerie (might happen) we join 1933..a record for an El Nino-like season
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19L. Should become Tony soon.
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Member Since: July 15, 2006 Posts: 175 Comments: 54864
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415. 7544
the cone can still shift west at 11pm imo stay tuned
Member Since: May 6, 2007 Posts: 0 Comments: 6874

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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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