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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Tropical Depression 19 and Tropical Storm Sandy to come at 5PM.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
BEGIN
NHC_ATCF
invest_RENUMBER_al902012_al192012.ren
FSTDA
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201210221931
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NOTIFY=ATRP
END
INVEST, AL, L, , ,
Member Since: Posts: Comments:
Quoting Hurricanes305:


How is that wishing casting he simply said Florida needs to keep watch because this is right in our backyard!


Well stated. The rule of thumb for those of us in South FL is that we should keep an eye on any storm to our south or southeast. This does not mean that we are wishcasting, we are being prudent. No track is set in stone this early. Crazy things can happen, like Wilma intensifying before hitting us when it was supposed to be sheared and weakened.
Member Since: July 10, 2011 Posts: 0 Comments: 80
Quoting HurricaneKing:
From my Local NWS out of Newport/ Morehead City NC

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 3 PM MON...LONG TERM PORTION OF THE FORECAST GOES FROM ONE
EXTREME TO THE OTHER. THE BROAD SURFACE HIGH ACROSS THE AREA IN
THE MIDWEEK TIMEFRAME WILL GRADUALLY BECOME ABSORBED INTO THE HIGH
BUILDING SOUTHEAST INTO NORTHERN NEW ENGLAND BY WEEK`S END. CLEAR
SKIES AND MILD TEMPS WILL BE THE RULE. THINGS BEGIN TO CHANGE
BEGINNING THIS WEEKEND. THE REST OF THE FORECAST WILL BE HIGHLY
DEPENDENT ON THE FUTURE TRACK OF WHAT IS LIKELY TO BE TROPICAL
SYSTEM SANDY. WILL NOT REHASH DIFFERENT SCENARIOS FROM VARIOUS
MODELS. WILL KEEP WITH HPC SOLUTION WHICH BRINGS THE SYSTEM VERY
CLOSE TO CAPE HATTERAS BY EARLY NEXT WEEK...WHICH IS CLOSE TO THE
22/00Z ECMWF MODEL.
WILL INTRODUCE SLIGHT CHANCE POPS SATURDAY AND
INCREASE TO LOW CHANCE SUNDAY INTO MONDAY.



with the HPC shifting its track closer to NC, Im not surprise that the NWS in Newport is siding with them
Member Since: August 19, 2006 Posts: 13 Comments: 15288
Quoting 954FtLCane:
Last time I checked the EURO is one of the more reliable models. Between 96 & 120 it seems that Sandy moves NNW on it's approach closet to FL. As you can see the wind field is pretty large.

96 hr

120 hr

There seems to be some sort of westward trend. I suspect this will stay east of S Fla but how far is the question.


If the center is further SW than the one from 2pm. Means it could get close to 80W or pass it by tomorrow morning. This would put S. Florida in the bulls eye with the models.
Member Since: May 25, 2012 Posts: 0 Comments: 2043

invest_RENUMBER_al902012_al192012.ren


Tropical Depression 19. Which one will be Sandy, which one will be Tony.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
Quoting 954FtLCane:
Last time I checked the EURO is one of the more reliable models. Between 96 & 120 it seems that Sandy moves NNW on it's approach closet to FL. As you can see the wind field is pretty large.

96 hr

120 hr

There seems to be some sort of westward trend. I suspect this will stay east of S Fla but how far is the question.
Surf is going to increase up and down the East Coast.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
anyway I'm out again guys
Member Since: June 13, 2009 Posts: 2 Comments: 12019
Quoting Tropicsweatherpr:
Recon found center more SW than where it was at 2 PM.



That can't be, there was no defiant west wind shift. It appears to be more north.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
255. 7544
Quoting wunderkidcayman:
I seeing a shift of forecast cone to the W soon


agree maybe they will wait till 11pm update tho its only 4 days away give or take
Member Since: May 6, 2007 Posts: 0 Comments: 6812
BEGIN
NHC_ATCF
invest_RENUMBER_al902012_al192012.ren
FSTDA
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040
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0000
201210221931
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NOTIFY=ATRP
END
INVEST, AL, L, , , , , 19, 2012, DB, O, 2012102012, 9999999999, , , , , , METWATCH, , AL192012
Member Since: April 29, 2009 Posts: 75 Comments: 14253
http://www.ssd.noaa.gov/goes/east/carb/flash-rb.htm l

Check out the last frame on the Caribbean rainbow loop. You can see a man's face clearly just to the SW of the Center. Just an observation, pretty eerie.
This Storm does look to be intensifying at a good clip this afternoon
Member Since: Posts: Comments:
From my Local NWS out of Newport/ Morehead City NC

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 3 PM MON...LONG TERM PORTION OF THE FORECAST GOES FROM ONE
EXTREME TO THE OTHER. THE BROAD SURFACE HIGH ACROSS THE AREA IN
THE MIDWEEK TIMEFRAME WILL GRADUALLY BECOME ABSORBED INTO THE HIGH
BUILDING SOUTHEAST INTO NORTHERN NEW ENGLAND BY WEEK`S END. CLEAR
SKIES AND MILD TEMPS WILL BE THE RULE. THINGS BEGIN TO CHANGE
BEGINNING THIS WEEKEND. THE REST OF THE FORECAST WILL BE HIGHLY
DEPENDENT ON THE FUTURE TRACK OF WHAT IS LIKELY TO BE TROPICAL
SYSTEM SANDY. WILL NOT REHASH DIFFERENT SCENARIOS FROM VARIOUS
MODELS. WILL KEEP WITH HPC SOLUTION WHICH BRINGS THE SYSTEM VERY
CLOSE TO CAPE HATTERAS BY EARLY NEXT WEEK...WHICH IS CLOSE TO THE
22/00Z ECMWF MODEL.
WILL INTRODUCE SLIGHT CHANCE POPS SATURDAY AND
INCREASE TO LOW CHANCE SUNDAY INTO MONDAY.

Member Since: Posts: Comments:
251. wunderkidcayman
7:37 PM GMT on October 22, 2012
I seeing a shift of forecast cone to the W soon
Member Since: June 13, 2009 Posts: 2 Comments: 12019
250. GTcooliebai
7:36 PM GMT on October 22, 2012
Quoting PalmBeachWeatherBoy:
(In)Accuweather has been predicting lows in the 50s for South Florida for Oct.29-Nov 2 for a few days now. That would be great this early in the fall.
If that were the case we would have 40s here in the Tampa Bay area.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
249. 954FtLCane
7:35 PM GMT on October 22, 2012
Last time I checked the EURO is one of the more reliable models. Between 96 & 120 it seems that Sandy moves NNW on it's approach closest to FL. As you can see the wind field is pretty large.

96 hr

120 hr

There seems to be some sort of westward trend. I suspect this will stay east of S Fla but how far is the question.
Member Since: September 30, 2008 Posts: 0 Comments: 108
248. Hurricanes305
7:34 PM GMT on October 22, 2012
Quoting kmanislander:


No surprise. I mentioned earlier that the 925 mb vort was West of the position in the advisory.

See map below which I previously posted but now updated.



So the center is further SW which means it more aligned with its mid-level circulation. If thats the cast this makes that eventually NNE turn quite a bit harder for the trough. The cone may coming more in line with the Euro/CMC rather than the GFS run from this morning
Member Since: May 25, 2012 Posts: 0 Comments: 2043
247. 7544
7:34 PM GMT on October 22, 2012
it be interesting to see the model runs once they get the hh data
Member Since: May 6, 2007 Posts: 0 Comments: 6812
246. Tropicsweatherpr
7:31 PM GMT on October 22, 2012
Member Since: April 29, 2009 Posts: 75 Comments: 14253
245. trHUrrIXC5MMX
7:30 PM GMT on October 22, 2012
Im pretty sure many people have gone there today...

Karl Parker says there could be "double-digit" rainfall in Haiti (also they have not fully recovered from the 7.0 quake of 2010.

Member Since: April 23, 2011 Posts: 104 Comments: 14873
244. TropicTraveler
7:30 PM GMT on October 22, 2012
There is an air of alarm being expressed but it seems too soon to say when the factors involved are so complex. This is the kind of situation where WU is at its most interesting.

Laughed at loud at Grothar's "No need for mead."
Member Since: July 24, 2007 Posts: 2 Comments: 924
243. kmanislander
7:29 PM GMT on October 22, 2012
Quoting Tropicsweatherpr:
Recon found center more SW than where it was at 2 PM.



No surprise. I mentioned earlier that the 925 mb vort was West of the position in the advisory.

See map below which I previously posted but now updated.

Member Since: August 19, 2006 Posts: 0 Comments: 15816
242. Hurricanes305
7:29 PM GMT on October 22, 2012
Quoting pmzqqzmp:


More wishcasting. Someone needs to control these people. No models have suggested in the least that it will strike So Fla.


How is that wishing casting he simply said Florida needs to keep watch because this is right in our backyard!
Member Since: May 25, 2012 Posts: 0 Comments: 2043
241. weaverwxman
7:28 PM GMT on October 22, 2012
IMHO I don't think saying S.Fla should watch this closely is a wishcast just a statement that maybe needed to be said.
Member Since: November 17, 2009 Posts: 0 Comments: 348
240. 7544
7:27 PM GMT on October 22, 2012
Quoting pmzqqzmp:


More wishcasting. Someone needs to control these people. No models have suggested in the least that it will strike So Fla.


d have you seen the models yet its going to be pretty close that so fla will still get some bad weather esp if it bloosoms on the west side p
Member Since: May 6, 2007 Posts: 0 Comments: 6812
238. Hurricanes305
7:26 PM GMT on October 22, 2012
Good Afternoon everyone, it seems that TD 18 continues to organize rather quickly since this morning. We may have Sandy by 5pm. In the short term it continues to crawl to the west it may still have a chance to get to 80W before a trough digs in and send it to the north or NNE. From there its still highly uncertain how close this gets to the US east coast. I'm not buying into the cone which forecast it to head out to sea. There is a narrow ridge to its north that can steer this back to the west and get close to Florida and eventually the east coast. However its too early and its all about timing.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
237. Abacosurf
7:25 PM GMT on October 22, 2012
Quoting Tropicsweatherpr:
Recon found center more SW than where it was at 2 PM.

I think it's clear on visible that it is SW of initial position. This confirms it.
Member Since: August 28, 2008 Posts: 0 Comments: 361
236. yqt1001
7:25 PM GMT on October 22, 2012
22/1745 UTC 22.0N 51.7W T2.0/2.0 90L

Well...this should be enough for classification.
Member Since: November 19, 2010 Posts: 1 Comments: 1286
235. Abacosurf
7:24 PM GMT on October 22, 2012
Quoting pmzqqzmp:


More wishcasting. Someone needs to control these people. No models have suggested in the least that it will strike So Fla.
But 3 models put it within 150 miles. Close enough for concern.
Member Since: August 28, 2008 Posts: 0 Comments: 361
234. Tropicsweatherpr
7:24 PM GMT on October 22, 2012
Recon found center more SW than where it was at 2 PM.

Member Since: April 29, 2009 Posts: 75 Comments: 14253
232. ncstorm
7:22 PM GMT on October 22, 2012
the HPC has come back west since this morning..duh duh duh..


Member Since: August 19, 2006 Posts: 13 Comments: 15288
231. CybrTeddy
7:22 PM GMT on October 22, 2012
90L is probably a tropical cyclone also.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
230. pmzqqzmp
7:22 PM GMT on October 22, 2012
Quoting Seflhurricane:
South florida needs to keep a close watch


More wishcasting. Someone needs to control these people. No models have suggested in the least that it will strike So Fla.
Member Since: August 25, 2011 Posts: 0 Comments: 46
229. stormpetrol
7:21 PM GMT on October 22, 2012
Time: 19:12:30Z
Coordinates: 12.9667N 78.7833W
Acft. Static Air Press: 983.9 mb (~ 29.05 inHg)
Acft. Geopotential Hgt: 160 meters (~ 525 feet)
Extrap. Sfc. Press: 1002.0 mb (~ 29.59 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 64° at 4 knots (From the ENE at ~ 4.6 mph)
Air Temp: 25.0°C (~ 77.0°F)
Dew Pt: 23.1°C (~ 73.6°F)
Peak (10s) Flt. Lvl. Wind: 5 knots (~ 5.8 mph)
SFMR Peak (10s) Sfc. Wind: -
SFMR Rain Rate: -
(*) Denotes suspect data
Member Since: April 29, 2007 Posts: 0 Comments: 7862
228. trHUrrIXC5MMX
7:21 PM GMT on October 22, 2012
who says TD18 or Sandy/Tony this is The EAST COAST KATRINA
Member Since: April 23, 2011 Posts: 104 Comments: 14873
227. ncstorm
7:20 PM GMT on October 22, 2012
well basically we are rolling dice and atlantic city looks to be oblilerated according to the CMC and Euro..LOL

PRELIMINARY UPDATE...

USED ONE-PART 00Z/22 ECMWF AND TWO-PARTS 00Z/22 ECENS MEAN TO
UPDATE THE PRELIMINARY FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7.
THERE ARE TWO MAJOR FEATURES AT THE MEDIUM RANGE INFLUENCING THE
FLOW- THE TROPICAL LOW EMERGING FROM THE CARIBBEAN SEA NORTHWARD
TO THE BAHAMAS, AND THE AMPLIFYING POLAR JET OVER THE CENTRAL AND
EASTERN UNITED STATES. JUST HOW THESE FORCES INTERACT IS CRUCIAL,
BUT AT THE TIME RANGE AT HAND, PREDICTING THEIR DANCE IS DICEY AT
BEST. FOR NOW, HAVE KEPT THE INCREASINGLY HYBRID CYCLONE OFF THE
EAST COAST, THOUGH NOT AS FAR OUT TO SEA AS THE GFS AND GEFS
MEMBERS. WILL COORDINATE WITH THE NATIONAL HURRICANE CENTER FOR
THE FINAL ISSUANCE. THE TROUGH DIGGING INTO THE INTERIOR IS
CONSIDERABLE, WITH MUCH OF THE NATION COOLING SUBSTANTIALLY. WEST
OF THE CONTINENTAL DIVIDE WILL BE DOMINATED BY MARITIME POLAR AIR,
WITH A MIXTURE OF CONTINENTAL POLAR AND ARCTIC AIR TO THE EAST
OVER THE NORTHERN PLAINS.


FINAL...

CHOOSE TO KEEP THE CIRCULATION THAT IS CURRENTLY TROPICAL
DEPRESSION 18 IN PLAY OFF THE EAST COAST THROUGH THE PERIOD, AND
CONSIDERING THE WILDLY DIVERSE DETERMINISTIC SOLUTIONS AND
ENSEMBLE MEMBERS FROM THE 12Z/22 CYCLE, THAT SEEMS TO HAVE BEEN A
SAFE BET. MADE NO CHANGES UPSTREAM OVER MOST OF THE UNITED STATES
FOR THE FINAL ISSUANCE, SAVE SOME COSMETIC TWEAKS. CONFIDENCE
REMAINS LOW, WITH THE POTENTIAL SENSIBLE WEATHER IMPACTS HIGH.
Member Since: August 19, 2006 Posts: 13 Comments: 15288
226. CybrTeddy
7:19 PM GMT on October 22, 2012
Quoting Thrawst:


That would be sort of insane. I'd project it to become a hurricane in 36 hours or so. needs to build an inner core.


It's happened every year since 2007.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
225. mo999999999
7:19 PM GMT on October 22, 2012
I hope that doom storm doesn't end up being insanely strong if it hits the US east coast.I live in canada anyway.
Member Since: September 23, 2012 Posts: 0 Comments: 21
224. CybrTeddy
7:18 PM GMT on October 22, 2012
Member Since: July 8, 2005 Posts: 259 Comments: 24018
223. ncstorm
7:18 PM GMT on October 22, 2012
12z JMA model..out to 144 hours
Member Since: August 19, 2006 Posts: 13 Comments: 15288
222. Tropicsweatherpr
7:15 PM GMT on October 22, 2012
Member Since: April 29, 2009 Posts: 75 Comments: 14253
221. Wunderwood
7:13 PM GMT on October 22, 2012
Quoting 7544:
with all these major models shifting west could we see a new cone by nhc shift further west tia


If they were to shift the cone, it would be a gradual shift. They don't put all their eggs in one basket. Just my opinion.
Member Since: July 10, 2011 Posts: 0 Comments: 80
220. 7544
7:10 PM GMT on October 22, 2012
with all these major models shifting west could we see a new cone by nhc shift further west tia
Member Since: May 6, 2007 Posts: 0 Comments: 6812
219. CybrTeddy
7:09 PM GMT on October 22, 2012
Recon flying in the clear, approaching TD18.
Member Since: July 8, 2005 Posts: 259 Comments: 24018
218. PalmBeachWeatherBoy
7:08 PM GMT on October 22, 2012
(In)Accuweather has been predicting lows in the 50s for South Florida for Oct.29-Nov 2 for a few days now. That would be great this early in the fall.
Member Since: August 30, 2006 Posts: 1 Comments: 477
217. Jedkins01
7:08 PM GMT on October 22, 2012
Quoting MAweatherboy1:
Um... yeah....




926 mb? Really? What's wrong with the models? How do they come to a conclusion like that?
Member Since: August 21, 2008 Posts: 0 Comments: 7440
216. HadesGodWyvern (Mod)
7:08 PM GMT on October 22, 2012
Philippines Atmospheric Geophysical Astronomical Services and Administration
Tropical Cyclone Advisory #1
TROPICAL DEPRESSION OFEL
11:00 PM PhST, October 22 2012
==============================

The Low Pressure Area east of Surigao Del Sur has developed into a tropical depression and was named "OFEL".

At 10:00 PM PhST, Tropical Depression Ofel [1000 hPa] located at 9.0°N 130.8°E or 460 km east of Hinatuan City, Surigao Del Sur has 10 minute sustained winds of 30 knots. The depression is reported as moving west at 8 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 300 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 5 AM tomorrow.
Member Since: May 24, 2006 Posts: 50 Comments: 45301
215. aspectre
7:08 PM GMT on October 22, 2012
Finally, invest_al182012.invest
AL18, 2012 10 22 12, 13.6n78.1w, 25knots, 1003millibars, TropicalDepression
AL18, 2012 10 22 18, 13.5n78.7w, 25knots, 1003millibars, TropicalDepression
Member Since: August 21, 2007 Posts: 0 Comments: 4860
214. HadesGodWyvern (Mod)
7:07 PM GMT on October 22, 2012
Japan Meteorological Agency
Tropical Cyclone Advisory #7
TROPICAL DEPRESSION 25
3:00 AM JST October 23 2012
====================================

SUBJECT: Tropical Depression In Sea East Of Mindanao

At 18:00 PM UTC, Tropical Depression (1004 hPa) located at 9.2N 131.4E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving west at 6 knots.

Dvorak Intensity: T2.0

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

24 HRS: 10.5N 128.6E - 35 knots (CAT 1/Tropical Storm) Sea East Of The Philippines
Member Since: May 24, 2006 Posts: 50 Comments: 45301

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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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