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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damm gom sst dam
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the models were correct with this one, i will drink to that ;)
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Quoting scott39:
98L is one of those that looks worse than what it is right now.
I meant looks better.
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Quoting ncwxman68:
sort of an analog for Hurricane Charley 1986.
I was thinking the same,but they had charley's origin point off the west coast of Fla.
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#37 Thank you Teddy for the link!
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I'd say that visually 98L looks better than TS Bonnie from last year.
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98L is one of those that looks worse than what it is right now.
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Quoting AllStar17:
Is an Ophelia-like track possible with 98L? That's one comparison that I can make.
any systems in mid july???
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Well ill call it a TD as soon as a start to see some banding.
Member Since: July 22, 2010 Posts: 1 Comments: 3851
Start cooking the popcorn at 12:15, lets hope recon checks this out today.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting AllStar17:


Looks like a developing cyclone to my untrained eyes.
2#
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Is an Ophelia-like track possible with 98L? That's one comparison that I can make.
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I'd say it's pretty close...

At least 50-70% at 2pm.

Member Since: June 9, 2007 Posts: 4 Comments: 15945
Quoting MrstormX:
Thunderstorms are really starting to pop now.



Looks like a developing cyclone to my untrained eyes.
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98L has to cough out all that dry air from the NW first, before any significant developement. I still think HH will still fly out today because of proximity to land and conditions are becoming more favorable.
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Once again for today's recon - keep this site up for good data, you'll need it! Bookmark it.
Link
Member Since: July 8, 2005 Posts: 259 Comments: 24455
some showers on the banana river misting and hazy winds picking up from the ne a sign its alittle s. of the port secure your boats e cen. flordians
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Thunderstorms are really starting to pop now.

Member Since: May 27, 2009 Posts: 0 Comments: 4438
sort of an analog for Hurricane Charley 1986.
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Quoting ProgressivePulse:


Not 100% sure however, I am pretty sure the pressure compared to it's surroundings is most important. Yes 1013 however it's forming in a higher pressure environment.


That is correct.
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Quoting scott39:
Higher pressures= slower developing TC.


Not 100% sure however, I am pretty sure the pressure compared to it's surroundings is most important. Yes 1013 however it's forming in a higher pressure environment.
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Quoting scott39:
Higher pressures= slower developing TC.
It needs to stay out of the GOM!! The ingredients there have the potential to bake a bad TC!
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Quoting CybrTeddy:
Man the curtains!
I'll be having my own blog update soon.


Curtains manned and standing by.
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Recon. will be interesting.
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IMO, no TD until tomorrow at the earliest.
Member Since: July 8, 2005 Posts: 259 Comments: 24455
Quoting weathermanwannabe:
Thanks Dr.; agree 100% with your analysis on 98L.....It's basically a wait and see until the storm develops and recon data is fed into the models for a better handle on potential track.....I would still be a little bit nervous if I was on the East coast of Florida if sheer was to really drop while the storm was near the Gulf Stream......... :)



It will be there 48hrs. PWATs over 2 inches in the area, one to watch for sure.
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Quoting ProgressivePulse:



Higher pressures= slower developing TC.
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I have a feeling that 98L has some surprises in store.
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Quoting nrtiwlnvragn:
Recent WindSat




A lot of rain contaminated readings however, moving right along in terms of closing off.
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Quoting ProgressivePulse:



I see some 1013 on the east coast.
Member Since: July 22, 2010 Posts: 1 Comments: 3851
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Quoting neutralenso:
the pattern is changing soon. 98L will move either into the carolinas, florida, or out to sea. in august the ridge protecting the US and the atlantic ridge will move meaning that the US gulf coast and east coast wont be protected. 98L could become a ts but a weak one
Ok, so this pattern is normal and last season was unusual in Aug and Seot?
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Quoting scott39:
That looks impressive on the visible. Do you have any current pressure readings in that area?



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Quoting ProgressivePulse:
Thanks for the Update Dr. Masters

As always, your opinion is greatly appreciated.


Thinking recon is indeed going to find a TD this afternoon, if not, flight 2. 98L seems to have made that commitment to develop looking at visible this morning.


I concur, plus NHC seems to really be relying on them more in this post QuikSCAT era.


Member Since: May 27, 2009 Posts: 0 Comments: 4438
the pattern is changing soon. 98L will move either into the carolinas, florida, or out to sea. in august the ridge protecting the US and the atlantic ridge will move meaning that the US gulf coast and east coast wont be protected. 98L could become a ts but a weak one
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Thanks Dr.; agree 100% with your analysis on 98L.....It's basically a wait and see until the storm develops and recon data is fed into the models for a better handle on potential track.....I would still be a little bit nervous if I was on the East coast of Florida if sheer was to really drop while the storm was near the Gulf Stream......... :)
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Man the curtains!
I'll be having my own blog update soon.
Member Since: July 8, 2005 Posts: 259 Comments: 24455
Recent WindSat


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Thanks for the Update Dr. Masters

As always, your opinion is greatly appreciated.


Thinking recon is indeed going to find a TD this afternoon, if not, flight 2. 98L seems to have made that commitment to develop looking at visible this morning.
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Quoting KEEPEROFTHEGATE:
POSS T.C.F.A.
XX/INV/98L
MARK
27.55N/77.77W
That looks impressive on the visible. Do you have any current pressure readings in that area?
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Last frame you can see new convection shooting up
Member Since: July 22, 2010 Posts: 1 Comments: 3851
from last blog

Quoting nrtiwlnvragn:
Offshore Waters Forecast

Excerpt:

SYNOPSIS FOR THE SW N ATLC INCLUDING THE BAHAMAS
1130 AM EDT SUN JUL 17 2011

.SYNOPSIS...A 1014 MB LOW NEAR 28N79W. THE LOW WILL MOVE S
THROUGH TONIGHT THEN TRACK IN A GENERAL WESTERLY DIRECTION MON
THROUGH TUE POSSIBLY MOVING ACROSS NORTHERN AND CENTRAL FLORIDA
WED. THE LOW COULD POSSIBLY DEVELOP INTO A TROPICAL CYCLONE.


there is couple of thing I have to argue about

ok

SYNOPSIS FOR THE SW N ATLC INCLUDING THE BAHAMAS
1130 AM EDT SUN JUL 17 2011
.SYNOPSIS...A 1014 MB LOW NEAR 28N79W. THE LOW WILL MOVE S THROUGH TONIGHT THEN TRACK IN A GENERAL WESTERLY DIRECTION MON THROUGH TUE POSSIBLY MOVING ACROSS NORTHERN AND CENTRAL FLORIDA WED. THE LOW COULD POSSIBLY DEVELOP INTO A TROPICAL CYCLONE

look at words in bold more so in italic ok
#1 its now 10:14 am my time 98L is already past the Northern Fl mark and is currently passing the Central Fl mark they say that S movement will continue tonight well if this happens at the speed I see it at it may even pass the Fl Keys Mark and just maybe the the Northern Cuba mark before MON/TUE when it does its westerly track
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Quoting hurricanehunter27:
As soon as the pressure starts to drop....
Thats definitely missing right now.
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POSS T.C.F.A.
XX/INV/98L
MARK
27.55N/77.77W
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Can't wait for recon.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
As soon as the pressure starts to drop....
Member Since: July 22, 2010 Posts: 1 Comments: 3851
Thanks DRM.
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thanks doc always depend on ya to set em straight
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I look for it to stay weak and Fl. may get a TD. Thanks Dr. Masters
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Thanks Dr. Masters!
Member Since: August 19, 2006 Posts: 13 Comments: 15996
nice blob off florida I see maybe some more rain for florida
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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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