98L may develop into a tropical depression near Florida; Ma-on a threat to Japan

By: Dr. Jeff Masters , 3:09 PM GMT on July 17, 2011

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A tropical disturbance (Invest 98L) has formed off the east coast of Florida, along the tail end of a cold front that pushed off the coast late last week. This disturbance has the potential to develop into a tropical depression that will bring heavy rains to the northern Bahamas and east coast of Florida today through Tuesday. Satellite imagery shows that the disturbance has become more organized this morning, with an expanding area of intense thunderstorms, the beginnings of a surface circulation, and upper-level outflow on the east and north sides of the storm. Some rotation of 98L is also evident on long-range radar out of Melbourne, Florida, but the rain showers are poorly organized and there is little evidence of low-level spiral banding. Wind shear is a moderate 10 - 20 knots, and sea surface temperatures are 27 - 28°C, which is plenty warm enough to support a tropical storm. There is dry, continental air over North Florida, and upper level winds out of the northwest are driving this dry air into the center of 98L, retarding development.


Figure 1. Morning satellite image of Invest 98L.

Forecast for 98L
The models are shy about developing 98L; only the HWRF model shows a tropical depression developing. The SHIPS model predicts that wind shear will be in the low to moderate range, 5 - 15 knots, over the next five days. NHC is giving 98L a 30% chance of developing into a tropical depression by Wednesday. Given the recent satellite and radar presentation of the storm, I'd put those odds higher, at 50%. A hurricane hunter aircraft is scheduled to investigate 98L this afternoon.

Steering currents are weak off the coast of Florida, and 98L can be expected to move slowly at less than 5 mph over the next two days. The HWRF and GFDL models predict 98L will execute a clockwise loop, heading towards the coast of Florida on Monday, then looping northeastwards towards South Carolina later in the week. The track of 98L will depend strongly on how intense the storm gets; a weak system is likely to stay farther to the south, while a stronger system will "feel" upper level winds with a west-to-east component, and tend to move to the northeast, parallel to the coast.

None of the reliable models predict tropical cyclone development over the remainder of the Atlantic through July 23.

U.S. heat wave to last at least another week
An unusually intense, widespread, and long-lasting heat wave over the majority of the U.S. continues to set numerous daily record highs. The latest long-range forecasts from the GFS and ECMWF models predict that the ridge of high pressure responsible for the heat wave will remain entrenched over the center or eastern portion of the country during the coming week, so the heat wave should continue for all but the Pacific Northwest through July 23. The GFS model does show that the ridge will break down some during the period 10 - 16 days from now, but such long range forecasts have low skill, and the heat wave could easily continue through the remainder of July. I'll present a more detailed look at the heat wave later this week.


Figure 2. Microwave satellite image of Typhoon Ma-on at 08:26 UTC July 17, 2011, over the West Pacific Ocean. The typhoon was undergoing an eyewall replacement cycle, with the inner eyewall collapsing and a new, larger eyewall forming from an outer spiral band. Image credit: Navy Research Lab, Monterey.

Typhoon Ma-on headed towards Japan
Powerful Category 3 Typhoon Ma-on is headed northwestward towards Japan, and is expected to brush the east coast of the main island of Honshu on Tuesday. The typhoon has weakened some over the past day, thanks to an eyewall replacement cycle where the inner eyewall collapsed, and a new, larger eyewall formed from an outer spiral band. Once this process completes, Ma-on is expected to intensify into a Category 4 storm. With water temperatures along the path of the typhoon ranging from 29 - 30°C, and wind shear expected to remain in the low to moderate range of 5 - 15 knots, Ma-on has the potential to hit Japan as a major Category 3 storm. The typhoon is unusually large, with winds of tropical storm force (39+ mph) extending out almost 350 miles to the north of the storm. A large portion of the south coast of Japan will receive tropical storm-force winds and large battering waves from Ma-on. Although the typhoon is currently a minimal Category 3 storm, its large size means that Ma-on has a tremendous amount of total kinetic energy, characteristic of a Category 5 storm. This means that Ma-on has the potential to bring a large and highly destructive storm to the coast on the right front side of where the eye makes landfall. If the eye remains just offshore, as some models are predicting, this storm surge will largely miss Japan, though.

Jeff Masters

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Quoting KEEPEROFTHEGATE:
jfv if i could i would spin one up right over your head and wrap you up in teh shower curtain to the top of you're head


LOL!! Too funny for sure...good ole JFV
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900. JLPR2
Quoting cloudburst2011:
70% chance that bret is going to be a fish storm no trouble to anyone but the fish and ships....with that being said everyone needs to turn there interest to the blob that just moved off the african coast...very impressive and the saharan dust has really diminished...this could be upgraded to cindy in 48 hours...



What?
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The NAM found a nugget :)


Member Since: September 23, 2005 Posts: 14 Comments: 10839
Quoting Guaricandilla2011:
Next indeed, Scott Guillet! Better enjoy this fish storm while you can, folks! Because this will ''NOT'' be the expected trend with storms this year, as you all have heard. Anyhow, I am pleased to say that the ECMW expects Cindy to hit Florida before month's end, now there's something to look forward to.
What the hell?
Quoting BaltOCane:
NOAA/NHC have yet to update their Facebook page.
I guess they have priorities, lol.

Activity in the Atlantic looks to be picking up.

Heat wave in the middle of the country will be here in Baltimore by Weds/Thurs. :-(
I with ya sista.I'll know how you feel as well since we live only 40 miles apart.
Member Since: August 14, 2010 Posts: 10 Comments: 16327
Quoting Guaricandilla2011:
Good afternoon, all; it's extremely unfortunate to see how TD-2 is forecast to head on out to sea, oh well, I guess.


You're either very sadistic or a troll.
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Quoting UKHWatcher:
100 weather related posts in 22 minutes!?!

This is why I keep laughing at the pple complaining about GW posts in here.... when there's real tropical wx to talk about, the only problem is how fast can you read 200 posts.... lol

Member Since: October 25, 2005 Posts: 19 Comments: 21190
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Guaricandilla2011:
Good afternoon, all; it's extremely unfortunate to see how TD-2 is forecast to head on out to sea, oh well, I guess.
jfv if i could i would spin one up right over your head and wrap you up in teh shower curtain to the top of you're head
Member Since: July 15, 2006 Posts: 168 Comments: 53285
this will go too the gulf i dont see it going out too sea not with that strong high
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Does anyone have some steak sauce and a Samuel Adams that I can wash some crow down with? I would have never guessed, that 98L would be a TD today!
Member Since: June 13, 2009 Posts: 0 Comments: 6728
Even the three-day cone is about 5 degrees of latitude wide.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
NOAA/NHC have yet to update their Facebook page.
I guess they have priorities, lol.

Activity in the Atlantic looks to be picking up.

Heat wave in the middle of the country will be here in Baltimore by Weds/Thurs. :-(
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I, for one, would like to see it meander north. The rain would be most welcome.
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Quoting AllStar17:
Remember that things can and will change. That path is not etched in stone. If I were in North Carolina I would keep an eye on the situation.


That means you presslord.
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884. 7544
so much for it going west west
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I knew jason would freak out over this.... lol.... prepared for it..... jk
Member Since: October 3, 2010 Posts: 40 Comments: 4129
000
WTNT42 KNHC 172042
TCDAT2

TROPICAL DEPRESSION TWO DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
500 PM EDT SUN JUL 17 2011

AN AIR FORCE HURRICANE HUNTER PLANE INVESTIGATING THE LOW PRESSURE
AREA JUST NORTH OF THE NORTHWEST BAHAMAS FOUND A WELL-DEFINED
LOW-LEVEL CENTER OF CIRCULATION...AND THE SYSTEM IS BEING
DESIGNATED AS A TROPICAL CYCLONE AT THIS TIME. ALTHOUGH WINDS OF
TROPICAL STORM FORCE WERE MEASURED BY THE SFMR INSTRUMENT ON BOARD
THE PLANE...THESE OBSERVATIONS WERE FLAGGED AS QUESTIONABLE. PEAK
FLIGHT-LEVEL WINDS REPORTED BY THE AIRCRAFT WERE 44 KT WHICH WOULD
NORMALLY INDICATE A SYSTEM OF TROPICAL STORM STRENGTH. HOWEVER...
THE CONVECTION NEAR THE CENTER IS RELATIVELY WEAK...AND IN THIS
CASE THE STRONGEST WINDS ARE LIKELY NOT MIXING DOWN TO THE SURFACE
AS MUCH AS TYPICALLY OCCURS. THE CURRENT INTENSITY ESTIMATE IS 30
KT. THE ATMOSPHERIC ENVIRONMENT IS NOT IDEAL FOR STRENGTHENING
WITH SOME DRIER AIR JUST TO THE NORTH AND NORTHWEST OF THE CYCLONE.
THE OFFICIAL INTENSITY FORECAST CLOSELY FOLLOWS THE LGEM AND
INTENSITY CONSENSUS GUIDANCE. NONE OF THE CURRENT MODEL RUNS SHOW
THE SYSTEM STRENGTHENING INTO A HURRICANE.

INITIAL MOTION IS A SOUTHWARD DRIFT. STEERING CURRENTS ARE LIKELY
TO REMAIN QUITE WEAK OVER THE NEXT DAY OR SO...AS THE SYSTEM IS
SITUATED IN A WEAKNESS IN THE SUBTROPICAL RIDGE. IN A COUPLE
OF DAYS...THE MID-LEVEL RIDGE TO THE SOUTHEAST OF THE TROPICAL
CYCLONE IS FORECAST TO STRENGTHEN SLIGHTLY AND THIS...ALONG WITH A
WEAK TROUGH PASSING NORTH OF THE CYCLONE...SHOULD INDUCE A GENERAL
NORTHEASTWARD MOTION. LATER IN THE FORECAST PERIOD...THE TRACK
GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON AN EAST-NORTHEASTWARD
MOTION AT AN INCREASING FORWARD SPEED. THE OFFICIAL FORECAST IS
RATHER CLOSE TO THE MODEL CONSENSUS AND TO THE LATEST ECMWF TRACK.

FORECAST POSITIONS AND MAX WINDS

INIT 17/2100Z 27.5N 78.2W 30 KT 35 MPH
12H 18/0600Z 27.4N 78.2W 40 KT 45 MPH
24H 18/1800Z 28.2N 77.8W 45 KT 50 MPH
36H 19/0600Z 29.0N 77.3W 50 KT 60 MPH
48H 19/1800Z 30.4N 76.5W 50 KT 60 MPH
72H 20/1800Z 32.0N 73.5W 50 KT 60 MPH
96H 21/1800Z 34.0N 67.0W 45 KT 50 MPH
120H 22/1800Z 36.0N 60.0W 40 KT 45 MPH

$$
FORECASTER PASCH/STEWART
Member Since: July 8, 2005 Posts: 259 Comments: 23501
Quoting Guaricandilla2011:
Good afternoon, all; it's extremely unfortunate to see how TD-2 is forecast to head on out to sea, oh well, I guess.


Things are really starting to look up i pray the U.S. Gulf Coast will be spared again this year and its looking good so far! Let them go out to sea!
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So in looking at the models we can start waving a big goodbye to TD2 eh? Looks like it will be going to live with the FISHES LoL!
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Quoting charlottefl:


NHC is and probably always will be conservative when it comes to forecasting. And I think probably for good reason. The exception is when there is an immediate threat to life and property, which there isn't with this system at the moment.


It's not far from land though. I don't like to criticise the NHC, I think they do very well generally, but they really dropped the ball here.
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Let's not forget how many times the NHC had to move the cone west for several systems last year....
Member Since: August 14, 2010 Posts: 10 Comments: 16327
It's nice to see the model-hugging folk get a pie in the face every once in a while...
Member Since: June 9, 2007 Posts: 4 Comments: 15776
876. Bonz
Good, looks like it'll stay away from me. That's a relief.
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Full update:
Tropical Depression Two:

35 Mph Winds
1010 MB
South @ 2
27.5 N ; 78.2 W

Forecast Track~



Wind Forecast(strength): 14% chance Hurricane

Member Since: October 3, 2010 Posts: 40 Comments: 4129
SPECIAL UPDATE Tropical Depression two forms 7/17/11

Enjoy!
Member Since: July 8, 2005 Posts: 259 Comments: 23501
The NHC cone is rather wide, too.
Member Since: June 29, 2009 Posts: 13 Comments: 5300

Quoting HarryMc:

So it looks like TD2 might get named tomorrow night?
Probably sooner than that. Conditions are conducive for development, warm waters of the Gulf Stream and wind shear is light: 5-10 knots.
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Das Feesh

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Serious delay in the discussion. Probably trying to figure out how to word their explanation for being so wrong.
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581 TaylorSelseth "Many places have laid off their veteran meteorologists because it's cheaper to hire an attractive 28yo bimbo to read off the model data.
Our local NBC affiliate fired our local well-loved meteorologist "too tall" Tom Szymanski because it was cheaper to have a young rookie just regurgitate the models.
"

Blame the NationalWeatherService for being too good at their job.
Some guest economists for Freakonomics ran a statistical study on TV weather forecaster vs the NWS. The sample size was too small to be a strong study but the representatives chosen were randomly selected. And the results were that over the long term, NWS beat every TVmeteorologist whose predictions differed from that of the NWS.
Not that the TVmeteorologists lost to the NWS every time they differed. But rather that for each prediction that they made that was more correct than that of the NWS's, they made more than one that was less correct. And the more often they disagreed with the NWS, the higher their percentage of blown forecasts.

Kinda like going to Vegas and "breaking even": most folks always remember their wins more than their losses. And can somehow ignore the fact that those billion-dollar casinos were built&operated from funds provided by people who "break even".

So hiring a "bimbo" who is bright and ambitious enough to learn what the NWS means when they issue their reports&charts ain't that bad a deal... especially considering that most of those women have a degree in meteorology, and just need to put in the time necessary to gain expertise (~10,000hours of actually doing the job, more or less depending on the field).
Brains and beauty ain't mutually exclusive. Far far more often than not, they're paired.

The problem with men is WAY too much ego, so way too much one-upmanship. And all too often for TVmeteorologists, disagreeing with the NWS is how they go for TopGun.
Taken as a whole, women aren't likely to have nearly the same level of overconfidence as men. And even when they do have high confidence in their abilities, they're far less likely to play TopGun for the sake of one-upmanship.
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Member Since: July 3, 2005 Posts: 419 Comments: 127377
865. JLPR2
Well look at that, I'm gone for an hour and we get a new TD.
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Remember that things can and will change. That path is not etched in stone. If I were in North Carolina I would keep an eye on the situation.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting hurricanehunter27:
ok who agrees with the NHC track?
Me.
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Quoting NICycloneChaser:
I can't believe they got something so close to land so wrong. Granted, it isn't going to cause any serious problems to land immediately, but nevertheless...


NHC is and probably always will be conservative when it comes to forecasting. And I think probably for good reason. The exception is when there is an immediate threat to life and property, which there isn't with this system at the moment.
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As long as T.D two stays out over water we won't have a problem....
Member Since: August 14, 2010 Posts: 10 Comments: 16327
Quoting hurricanehunter27:
ok who agrees with the NHC track?
I do agree that it will end up heading NE or ENE, but I don't think it will begin that motion as quickly as the hurricane center predicts.

The NHC must have some uncertainty in its track as well, or else they wouldn't have issued the watches for the bahama islands south of the storm's current location.
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Quoting Drakoen:


So it looks like TD2 might get named tomorrow night?
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Quoting hurricanehunter27:
ok who agrees with the NHC track?


I agree with the general track, I just think it's a little fast.
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I think their track north is too fast, could have more time in a good environment for strengthening. Just my opinion.
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18z Early Cycle NHC model tracks
Invest98
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)




Early Model Wind Forecasts

Member Since: July 3, 2005 Posts: 419 Comments: 127377
293

WTNT32 KNHC 172034

TCPAT2



BULLETIN

TROPICAL DEPRESSION TWO ADVISORY NUMBER 1

NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011

500 PM EDT SUN JUL 17 2011



...TROPICAL DEPRESSION FORMS JUST NORTH OF THE NORTHWEST BAHAMAS...





SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION

----------------------------------------------

LOCATION...27.5N 78.2W

ABOUT 100 MI...165 KM NW OF GREAT ABACO ISLAND

MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H

PRESENT MOVEMENT...S OR 180 DEGREES AT 2 MPH...4 KM/H

MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES





WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY...



THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A TROPICAL STORM WATCH FOR

GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST BAHAMAS.



SUMMARY OF WATCHES AND WARNINGS IN EFFECT...



A TROPICAL STORM WATCH IS IN EFFECT FOR...

* GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST BAHAMAS





FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR

PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.





DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

AT 500 PM EDT...2100 UTC...THE CENTER OF TROPICAL DEPRESSION TWO WAS

LOCATED NEAR LATITUDE 27.5 NORTH...LONGITUDE 78.2 WEST. THE

DEPRESSION IS DRIFTING TOWARD THE SOUTH NEAR 2 MPH...4 KM/H...AND

LITTLE MOVEMENT IS EXPECTED OVERNIGHT...FOLLOWED BY A SLOW

NORTH-NORTHEASTWARD MOTION ON MONDAY.



MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/H...WITH HIGHER

GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 48

HOURS...AND THE DEPRESSION COULD BECOME A TROPICAL STORM TONIGHT.



THE MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE RESERVE UNIT

HURRICANE HUNTER AIRCRAFT WAS 1010 MB...29.83 INCHES.





HAZARDS AFFECTING LAND

----------------------

RAINFALL...THE DEPRESSION COULD PRODUCE TOTAL RAINFALL AMOUNTS OF 2

TO 3 INCHES OVER THE NORTHWEST BAHAMAS.



SURF...LOCALLY HIGH SURF CONDITIONS CAN BE EXPECTED ALONG NORTH AND

WESTERN FACING BEACHES IN THE NORTHWEST BAHAMAS THROUGH TONIGHT.





NEXT ADVISORY

-------------

NEXT INTERMEDIATE ADVISORY...800 PM EDT.

NEXT COMPLETE ADVISORY...1100 PM EDT.



$$

FORECASTER PASCH/STEWART
Member Since: July 15, 2006 Posts: 168 Comments: 53285
ok who agrees with the NHC track?
Member Since: July 22, 2010 Posts: 1 Comments: 3841

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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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