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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wonder how close recon is getting?
Member Since: Posts: Comments:
Quoting Stormchaser2007:
AL, 98, 2011071712, 03, SHIP, 0, 282N, 788W, 20, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 12, 289N, 793W, 23, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 24, 283N, 800W, 27, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 36, 277N, 810W, 31, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 48, 273N, 819W, 36, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 60, 270N, 827W, 39, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 72, 271N, 830W, 43, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 84, 272N, 832W, 46, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 96, 272N, 832W, 47, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 108, 270N, 833W, 49, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 120, 268N, 835W, 50, 0, , 0, , 0, 0, 0, 0,


Holy cow!!!
Member Since: Posts: Comments:
Quoting jasonweatherman2011:
AT 2PM going up to 40%!!
I concur!
Member Since: June 13, 2009 Posts: 0 Comments: 6732
Quoting CybrTeddy:
IMO, I wouldn't be shocked if 98L got 60% at 2 pm though 50% sounds reasonable.


Not sure since it looks like Stewart is the specialist this cycle.
Member Since: September 23, 2005 Posts: 14 Comments: 10875
Quoting Stormchaser2007:


Wow. Definitely getting that look.
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Quoting FLdewey:
Guess I'm not taking the Donzi out for a dinner cruise...



C'mon, where's your sense of adventure? ;)
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting Stormchaser2007:

That could be a TS right there
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Quoting Stormchaser2007:


I'd say that's a tropical cyclone.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting Stormchaser2007:


Impressive
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Member Since: June 9, 2007 Posts: 4 Comments: 15776
I think he will go RED next update if not a TD
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Quoting CybrTeddy:
IMO, I wouldn't be shocked if 98L got 60% at 2 pm though 50% sounds reasonable.


Thats what I am thinking as well.
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IMO, I wouldn't be shocked if 98L got 60% at 2 pm though 50% sounds reasonable.
Member Since: July 8, 2005 Posts: 259 Comments: 23565
Quoting jasonweatherman2011:
AT 2PM going up to 40%!!

I would say, 80% or even 90%, wouldn't be surprised if it was a TD now
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Probably 50-60% at 2, then a special update if recon find something (which seems likely).
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AL, 98, 2011071712, 03, SHIP, 0, 282N, 788W, 20, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 12, 289N, 793W, 23, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 24, 283N, 800W, 27, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 36, 277N, 810W, 31, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 48, 273N, 819W, 36, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 60, 270N, 827W, 39, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 72, 271N, 830W, 43, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 84, 272N, 832W, 46, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 96, 272N, 832W, 47, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 108, 270N, 833W, 49, 0, , 0, , 0, 0, 0, 0,
AL, 98, 2011071712, 03, SHIP, 120, 268N, 835W, 50, 0, , 0, , 0, 0, 0, 0,
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Just got out of Harry Potter at Sawgrass. The sky has a few whispy sirrus cloud but is just as blue as it gets.
But to the east...grey with low level clouds in the what appears to be the beginnings of spiral bands.

Anyone farther east able to confirm?
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Quoting Patrap:


That's the blob I'm watching. We're supposed to get rain from that before all this dry air sucks the life out of it. Sigh. If it makes it this far.
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One should be prepared come June 1 every year.





Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting jasonweatherman2011:
AT 2PM going up to 40%!!


do you know this or are you guessing because to me it looks more like 60-70%
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Quoting jasonweatherman2011:
AT 2PM going up to 40%!!

I say it goes to a red alert
Member Since: July 22, 2010 Posts: 1 Comments: 3841
Quoting jasonweatherman2011:
AT 2PM going up to 40%!!


If not higher, J.
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Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting leofarnsworth:
According to the best minds in this business, the models did not predict the 'blob' off the coast. But could a train meteorologist who understands the history of cut off lows have at least warned about this? Is it possible people are getting lazy in their reliance on the models since the models seem to consistently miss certain types of development? No offense meant to people relying on the models, but now coastal business people like myself are left scrambling.


Don't know where you are located but you should read the Forecast Discussion from your local NWS office. Both Melbourne and Miami have mentioned the possibility of development since last tue-wed.
Member Since: September 23, 2005 Posts: 14 Comments: 10875
Looks like the main circulation center is forming around 78-28
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Quoting MrstormX:


I miss Lyons, good guy... got it wrong sometimes, but never overlooked anything. I bet he got fed up with how hokey the Weather Channel has become.


Yes but everyone gets one wrong and some point.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Blog Update!
Invest 98L ; Typhoon Ma-on threatens Japan
Comment, and if you have questions about the subjects on my blog, or just have a question about whats going on in the tropics today, i will do my best to answer it.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
lets have a cheeer for darren clarke british open champion hip hip hooray
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Quoting AllStar17:


Why don't they make Jim Cantore the expert? Knabb only is on in the morning and talks for like 15 seconds. Dr. Lyons was really good but isn't there anymore unfortunately.


I miss Lyons, good guy... got it wrong sometimes, but never overlooked anything. I bet he got fed up with how hokey the Weather Channel has become.
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Quoting MrstormX:


Thats why they had to bring in Norcross last year as well, Knabb is a good forecaster but he can be pretty complacent as well.
That's why I come here for tropical weather insted of TWC.
Member Since: August 14, 2010 Posts: 10 Comments: 16406
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting hurricanehunter27:

Wow....total reliance on the models, now thats no good.


Thats why they had to bring in Norcross last year as well, Knabb is a good forecaster but he can be pretty complacent as well.
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Quoting MrstormX:


I know TWC snubbed the storm twice last night, no mention at all. This morning it got like a 30 second discussion, and then they began talking about digital media.


Why don't they make Jim Cantore the expert? Knabb only is on in the morning and talks for like 15 seconds. Dr. Lyons was really good but isn't there anymore unfortunately.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
pretty sure the hunters will take a look at it this evening
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Quoting AllStar17:


Yesterday he said he didn't expect any development over the next few days, including 98L. I believe it was posted on his Facebook page.

Dr Masters has a nice dish of CROW ready for him too.
From 14July
The Atlantic is quiet
None of the reliable models predict tropical cyclone development over the next seven days.

From last blog 15 July
The Atlantic is quiet
None of the reliable models predict tropical cyclone development through July 21.
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Quoting AllStar17:


What are your thoughts on this system? TIA!



I think we have a developing system on our hands.

Not going to go into too much detail until recon has made it's run, but I don't think that this system is Gulf-bound.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
783

URNT10 KNHC 171656

97779 16554 10277 85808 73100 03012 67683 /5763

RMK AF302 WXWXA 110717151118302 OB 04

SWS = 21 KTS
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting CybrTeddy:


Knabbs said development wasn't going to happen and that this would dissipate due to lack of model support.

Wow....total reliance on the models, now thats no good.
Member Since: July 22, 2010 Posts: 1 Comments: 3841
Quoting MrstormX:


I know TWC snubbed the storm twice last night, no mention at all. This morning it got like a 30 second discussion, and then they began talking about digital media.


Well, I just watched the 12:50 tropical update and it was pretty good. Warren Madden was doing it and he usually is very good IMO.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting AllStar17:


Yesterday he said he didn't expect any development over the next few days, including 98L. I believe it was posted on his Facebook page.


I know TWC snubbed the storm twice last night, no mention at all. This morning it got like a 30 second discussion, and then they began talking about digital media.
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POSS T.C.F.A.
XX/INV/98L
MARK
27.87N/77.97W
Member Since: July 15, 2006 Posts: 169 Comments: 53296
According to the 0z forecast steering charts a NNE movement is more likely as we head toward Monday afternoon. Just a wait and see game..

Photobucket
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.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Quoting MrstormX:


What did the TWC kids say this time?


Knabbs said development wasn't going to happen and that this would dissipate due to lack of model support.
Member Since: July 8, 2005 Posts: 259 Comments: 23565
Nice looking TD we have here.
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Quoting washingtonian115:
Does anybody see that large complex of thunderstorms coming off of Africa?.I know their's a low percentage of it developing.But it may be signs off things to come....
I talked about it in my post 116. This looks like first real threat for a CV cyclone to me...

Meanwhile the EPac low still embedded in the monsoon trough....

BRB...

Member Since: October 25, 2005 Posts: 19 Comments: 21484

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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.