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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gooooooooooooooooooooooooooooooAL
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I call posting Td two on wikapedia first!!!!!!!!
Member Since: October 3, 2010 Posts: 40 Comments: 4129
goal
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Just had some 50 mph winds and looks like it starting to build to the west again
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2011 Storms
All Active Year


Atlantic
02L.TWO

East Pacific
94E.INVEST

Central Pacific

West Pacific
08W.MA-ON

Indian Ocean

Southern Hemisphere
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732- joe- you're a barrel of laughs, aren't you?

TEASE-CASTER!
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Greenball 02L.TWO on NRL site.
Member Since: July 8, 2005 Posts: 259 Comments: 23574
No need for that,any changes pop up here now
Member Since: July 3, 2005 Posts: 421 Comments: 127569
Quoting txjac:
Dangit ...got to go grocery shopping ...just when things get exciting ...

See ya all when I get back ...anyone need anything since I'm going out?
Bring back some ranch dorritos.
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Quoting TxHurricanedude11:
Hey so much for that 40% issued by the nhc lol told ya it should've been around 60%...crow for the stewart man.


Crow for everyone this time. The TWO issues 48 hour potential percentages. 48 hours ago, there was no mention of this system, not even a near 0%. This was one of those quick spinners.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
*on NHC site.

F5..F5.. F5.. Fresca.. F5.. F5..
Member Since: July 8, 2005 Posts: 259 Comments: 23574
Quoting fsumet:
TD 2, Tropical Storm Watch for the Bahamas. Forecast to get up to 50 knots.


where do you see watches posted yet?
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Quoting txjac:
Dangit ...got to go grocery shopping ...just when things get exciting ...

See ya all when I get back ...anyone need anything since I'm going out?

RediWhip.
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Well, assuming we get Bret out of this, we're about 5 days ahead of last season in terms of number of storms.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
Member Since: July 3, 2005 Posts: 421 Comments: 127569
Quoting txjac:
Dangit ...got to go grocery shopping ...just when things get exciting ...

See ya all when I get back ...anyone need anything since I'm going out?


Sure. If ya see any rain point it my way. ;)
Member Since: August 24, 2010 Posts: 0 Comments: 677
734. 7544
Quoting txjac:
Dangit ...got to go grocery shopping ...just when things get exciting ...

See ya all when I get back ...anyone need anything since I'm going out?


we need a cone we need a cone
Member Since: May 6, 2007 Posts: 0 Comments: 6690
Quoting TxHurricanedude11:
Hey so much for that 40% issued by the nhc lol told ya it should've been around 60%...crow for the stewart man.



sould have been 70 too 80% at lest
Member Since: May 21, 2006 Posts: 5091 Comments: 114731
Quoting AllStar17:


What are your thoughts on a possible track?


I think it's going to take the "perfect track",going to head sw and dump 8-10 inches of rain on s.e. florida, head west and re-energize over the everglades, head north hit naples,ft myers,sarasota,tampa/st pete all with enough rain to erase any YTD rainfall totals, it will then drift nw and re-energize again over the north central gulf, will become a minimal hurricane,trk wnm, making a landfall in texas and going inland and stall, erasing all rainfall deficits for Texas.
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Quoting nrtiwlnvragn:
NHC has not classified yet in ATCF, still have as "DB".


They did that when the renumber came out for Arlene too.
Member Since: July 8, 2005 Posts: 259 Comments: 23574
Quoting Hurricanes101:
based on the numbers from the atcf, I would say TD2
Info for the system is not up yet on the Navy page but it does say 02L which is a TD, correct ?
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729. txjac
Dangit ...got to go grocery shopping ...just when things get exciting ...

See ya all when I get back ...anyone need anything since I'm going out?
Member Since: April 24, 2010 Posts: 1 Comments: 2457
can't there be other facility that can classify tropical cyclones here in the Atlantic?
These people are so sssssslllllloooooowwwwwww.....
Member Since: April 23, 2011 Posts: 104 Comments: 14871
NHC has not classified yet in ATCF, still have as "DB".
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Quoting NICycloneChaser:
Here, NHC, let me pick that ball up off the floor for you.


ROFLMAO...
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Quoting cchsweatherman:


I'm talking about ridging building over Florida by mid-week.
Right, it will long after its out to sea.
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well see a special update of 100% TC in the next 48 hrs. then at 5pm advisory TD 2
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Well we have T.D 2 eh?.That was really fast.
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AL, 02, 2011071718, , BEST, 0, 277N, 783W, 30, 1011, DB, 34, NEQ, 0, 0, 0, 0, 1016, 150, 50, 0, 0, L, 0, , 0, 0, TWO, M,

It's TD 2, not Bret, but we have classification!
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Heck we all knew it was going to be a TD#2...
But now how soon before it is called a TS "Bret"???

Taco :o)
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Quoting ncstorm:
the stronger the storm is, the more it will feel the effects of that northward pull..remember, we have another DMAX..might be waking up to a TS in the morning..


Correct. An out to sea track sounds like a likely scenario.
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TD 2, Tropical Storm Watch for the Bahamas. Forecast to get up to 50 knots.
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717. SLU
Cindy?

Member Since: July 13, 2006 Posts: 12 Comments: 4859
NHC Model Overview


Meteorologists at the National Hurricane Center (NHC) have a variety of prediction models available to provide guidance for their forecasts of tropical cyclone tracks and intensity. The intent of this paper is to provide a brief overview of each of the models. Forecasters may find this information helpful when considering NHC discussions which mention the performance of individual models. A primary reference is provided after the summary of each model for readers who desire more information. NOTE: All thumbnail graphics in this Web document are linked to larger version of the graphics. Just click the thumbnail to view the larger version.

As noted by Neumann (1979), models for the prediction of tropical cyclone motion and intensity may be classified as either statistical or dynamical. Statistical models rely on what has happened-the climatology of past storms, for example. Dynamical models can be classified as either barotropic or baroclinic. Statistical-dynamical models are an intermediate class that incorporate numerically forecast data into a statistical prediction framework, similar to the Model Output Statistics used to provide guidance for specific parameters such as temperature and probability of precipitation.



BAM - The Beta and Advection Model

The Beta and Advection Model is a baroclinic-dynamical track prediction model. It produces a forecast track by following a trajectory in the vertically averaged horizontal wind starting at the current storm location out to 120 hours. The trajectory is corrected to account for the variation of the Coriolis force with latitude, the so-called Beta effect. (Beta is the Greek letter frequently used in meteorological equations to represent the change in the Coriolis parameter with latitude.)

The figure shows how the conservation of absolute vorticity results in the formation of anticyclonic relative vorticity in the northeast quadrant of the storm, and the formation of cyclonic relative vorticity in the southwest quadrant of the storm: Diagram of absolute vorticity advection and relative vorticity formation in the vicinity of a tropical cyclone.. The result adds a component of motion to the northwest to the storm's trajectory.

Three versions of the BAM model are run with shallow (850-700 mb), medium (850-400 mb), and deep (850-200 mb) layers. All three versions of the model are run operationally four times per day.

Reference: Marks, D. G., 1992: The beta and advection model for hurricane track forecasting. NOAA Tech. Memo. NWS NMC- 70, 89 pp.

Member Since: July 3, 2005 Posts: 421 Comments: 127569
Here, NHC, let me pick that ball up off the floor for you.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
Quoting Stormchaser2007:
And if this becomes Bret...

We will be ahead of last year.

Food for thought.


Well last year didn't blow up until late August so it isn't too difficult to overtake 2010 in early season activity.
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Quoting TampaFLUSA:

Which one?? NWS Miami agrees w E movement as of 2pm discussion, and Melbourne says nothing about it moving over the state. Sorry.


I'm talking about ridging building over Florida by mid-week that all NWS offices had forecast this morning.
Member Since: April 14, 2007 Posts: 8 Comments: 5163
WHOOOP!!
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Navy site gone amuck, they dont know what happened
Member Since: October 3, 2010 Posts: 40 Comments: 4129
I am curious if this is either TD#2 or TS Bret. But we defiantly just cranked out our 2nd system of the year.
Member Since: July 8, 2005 Posts: 259 Comments: 23574
based on the numbers from the atcf, I would say TD2
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20 posts in less than 4 minutes...
Member Since: October 25, 2005 Posts: 19 Comments: 21487
As is typical with these, instead of bringing us rain, 98L will effectively supress Florida's normal diurnal showers and thunderstorms for several days. Nothing else of note from it here in Florida, but it will still be interesting to watch the system develop.
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And if this becomes Bret...

We will be ahead of last year.

Food for thought.
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i think i just pooped by pants, and spit my coke everywhere...

So Td eh? okay.... let the crow flinging begin. who's first?
Member Since: October 3, 2010 Posts: 40 Comments: 4129
it's cool Virgil, I was laughing at your post, too. :)
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the stronger the storm is, the more it will feel the effects of that northward pull..remember, we have another DMAX..might be waking up to a TS in the morning..
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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.