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 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: 20734
Quoting MrstormX:


What did the TWC kids say this time?


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.
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And a moderate risk for severe weather goes up ND and MN
Member Since: July 6, 2011 Posts: 0 Comments: 2210
Quoting FLdewey:
Wow this storm got a Katrina reference yesterday, and an Andrew reference today.

It'll be typhoon Tip by Monday at this rate.
By Tuesday a hypercane
Member Since: July 22, 2010 Posts: 1 Comments: 3813
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Quoting Stormchaser2007:
FULL IMAGE




What are your thoughts on this system? TIA!
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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.
If in fact it developes it won't become much.These things can happen.And people on the blog have been warning about this situation a week in advance.These type of systems can be 'missed" by the models.Their not very reliable when it comes to these types of things in some cases.
Member Since: August 14, 2010 Posts: 10 Comments: 15716
Quoting AllStar17:
Dr. Rick Knabb on TWC may have to eat some crow.


What did the TWC kids say this time?
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FULL IMAGE


Member Since: June 9, 2007 Posts: 4 Comments: 15718
Dr. Rick Knabb on TWC may have to eat some crow.
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BahaHurican:Though they were talking something further north, I think.... ncstorm?

yes, I can say I have been pointing out this scenario for a while now..some of the models even the ECWMF was predicting this set up..the question was where the low would develop..but If I remember correctly, NOGAPS had this stalling for three days off of SC..I do think this storm will stall and intensify off of Fl as a ts and I am going out on the limb and say a weak cat 1 if this turns up to the north as what most experts are saying and gets in the gulf stream heading towards NC..seen it happen before with Charley when it crossed Fl..imo
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Quoting hurricane23:
Dont want to speculate any futher on track until recon gets in there. I think its a good bet recon finds a pretty well developed surface circulation.


Hey "killer," good to see you.
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looks like it;s trying to wrap around some sort of center
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Blog update!
98L becoming better organized off Florida 7/17/11
Member Since: July 8, 2005 Posts: 259 Comments: 23013
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Fresh OPC Map, no doubts it is detached now.

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Quoting BahaHurican:
Hey, h23. I'm thinking we're going to have a bit of a drifter anyway for the next 24 at least. Steering doesn't seem strong and the system is still basically getting its act together.
for the first 24
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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.
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Quoting BadHurricane:




lol lmao not likely but if u notice wind shear is dropping a bit fast
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Quoting KEEPEROFTHEGATE:
we know more soon may be 02L coming up


I hope, I'm getting bored.
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Quoting hurricane23:
Dont want to speculate any futher on track until recon gets in there. I think its a good bet recon finds a pretty well developed surface circulation.
Hey, h23. I'm thinking we're going to have a bit of a drifter anyway for the next 24 at least. Steering doesn't seem strong and the system is still basically getting its act together.
Member Since: October 25, 2005 Posts: 19 Comments: 20734
Quoting MrstormX:


Inbound as we speak.
we know more soon may be 02L coming up
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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....
Member Since: August 14, 2010 Posts: 10 Comments: 15716
Quoting MrstormX:


Recon should tell us.
.
Just looked at sat images of 98L, I would say it has a COC. Convection is being pushed SE.
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In the suburbs north of Chicago we have a heat index of 92 and dew point of 69, along with an Ozone Action Day. It's not noon yet, so I expect the numbers will get worse. Don't want to catch up to Fargo, though.

I hope 98L (or whatever it becomes) stays away from the GOM! That would be really bad with those SST.

There's a blob off Apalachicola that bears watching.
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Quoting mgdimarco:
Doesn't this appear to be a set-up for the Hurricane Andrew scenario?


Ohhhhh....
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Quoting AussieStorm:
It;s up now? or later ?


Inbound as we speak.
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Quoting MrstormX:


Recon should tell us.
It;s up now? or later ?
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I don't think 98L will go into the GOM.Their is a low percentage of that happening(for now).
Member Since: August 14, 2010 Posts: 10 Comments: 15716


Unfortunately the rain chances are dropping for the state. Last night the chances were 40 to 50 percent each day for the next week. This morning they have dropped to 20 to 30 percent with exception of today. Moisture will be sucked away unless of coarse the blob moves West.
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Recon away.
Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 17th day of the month at 16:37Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 01

Mandatory Data...

Observation Time: Sunday, 16:30Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 28.7N 88.1W
Location: 132 miles (212 km) to the SSE (153°) from Gulfport, MS, USA.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 7,310 meters
Flight Level Wind: From 80° at 15 knots (From the E at ~ 17.2 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: -17°C
Flight Level Dew Point: -18°C
Weather (within 30 nautical miles): Overcast / Undercast
400 mb Surface Altitude: 7,630 geopotential meters
Member Since: July 8, 2005 Posts: 259 Comments: 23013
Quoting AussieStorm:
Any Idea if 98L has a COC?


Recon should tell us.
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Dont want to speculate any futher on track until recon gets in there. I think its a good bet recon finds a pretty well developed surface circulation.
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Any Idea if 98L has a COC?
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Quoting MrstormX:
Could the BAMM actually be right for once?
I thought it was BAMS taking it west.... which might be the case if it stays shallow.

Quoting AllStar17:


Although I do remember some people pointing out the possibility of this situation a couple days ago.
Though they were talking something further north, I think.... ncstorm?

Quoting mgdimarco:
Doesn't this appear to be a set-up for the Hurricane Andrew scenario?
Not really. Closest thing, if it developed AND still went west, might be maybe Jeanne... from recent times, anyway. Andrew was pretty much a straight arrow through the heart of the Bahamas and S FL....

Member Since: October 25, 2005 Posts: 19 Comments: 20734
Large tornado couplet near Harvey ND
Member Since: July 6, 2011 Posts: 0 Comments: 2210
I guess something erodes that ridge to the north of 98L

only explanation, because current steering does not match what the models are stating and that is on any level of steering; winds would push this West and WSW; something must change drastically for the model tracks to pan out
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Quoting hurricane23:


Leaning towards minimal impact in FL.



Hey H23,


Whats your thoughts on 98L?
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Quoting AllStar17:


Yes but it is continuing to move south.


This is what is pushing it South for now. Expected to change. (Hey, what happened to your weather Trivia this year in the off-season. We enjoyed them last year.

Link
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Quoting hurricane23:


Leaning towards minimal impact in FL.
This looks more like a South/North Carolina event rather than Florida.
Member Since: August 14, 2010 Posts: 10 Comments: 15716
Quoting hurricane23:


Leaning towards minimal impact in FL.



Hold hope Adrian, we need all the rain we can get.
Member Since: August 19, 2005 Posts: 5 Comments: 4863
Certainly wasn't what I was expecting to see this morning.

Couple of comments: I agree that going north against the ridge doesn't look possible, going to have to wait and see how that plays out.

Hurricane Andrew set-up: no - Andrew came across the Atlantic and had time to develop -- this is already close to the coast -- there would not be time for this to develop in the same manner.

Hopefully it will bring a lot of rain to central & North florida, will help a lot towards the drought.
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Looks like Recon is on the way


Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 17th day of the month at 16:37Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 01

Mandatory Data...

Observation Time: Sunday, 16:30Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 28.7N 88.1W (View map)
Location: 132 miles (212 km) to the SSE (153) from Gulfport, MS, USA.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 7,310 meters
Flight Level Wind: From 80 at 15 knots (From the E at ~ 17.2 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: -17C
Flight Level Dew Point: -18C
Weather (within 30 nautical miles): Overcast / Undercast
400 mb Surface Altitude: 7,630 geopotential meters
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Quoting mgdimarco:
Doesn't this appear to be a set-up for the Hurricane Andrew scenario?


Not even close
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Quoting Grothar:


Morning PP, Seems most of the models have it moving back North at this time.






Stalled to a slight S drift. Appears to me that it's consolidating a little further E than where the low is currently depicted.
Member Since: August 19, 2005 Posts: 5 Comments: 4863
Quoting mgdimarco:
Doesn't this appear to be a set-up for the Hurricane Andrew scenario?

Nope.
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000
URNT10 KNHC 171626
97779 16250 11289 94200 70100 08015 64//2 /5765
RMK AF303 WXWXA 110717150241303 OB 02
;


Playing the waiting game at this point...
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.