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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Hurricane Hunters crossing over Central Florida and about to head out over the Atlantic Ocean towards the disturbance. I'm expecting that recon will find a better organized system than the NHC is currently suggesting.
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351. Skyepony (Mod)
AF304 is descending into the storm.
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Quoting CybrTeddy:
Interesting second system, models have been showing a low pressure system out here and I mentioned we'd have to watch this area for tropical development over the weekend on Friday.
Is that the front holding onto 98L?
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Quoting lazerpointernerd:


What feature of google earth are you using to see this?

Tropicalatlantic
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Quoting Patrap:
Its not weird at all. A P-3 NOAA, A AF HH Teal Flight and a NOAA G-4 are all relevant atm.


Exactly. One will be investigating the actual disturbance while the other two are sampling the atmosphere around the disturbance gathering information that could make the forecasting better on this.
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Here, take a look, you need a decoder plug-in:

Link

Quoting lazerpointernerd:


What feature of google earth are you using to see this?
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LOL 98L is going too get mad with all the HH flying a round
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting Patrap:
Did dey drop a sonde CT ?

: )


Yea, went out to look at it and they plopped it straight on my head ;)
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Quoting lazerpointernerd:


What feature of google earth are you using to see this?


http://www.tropicalatlantic.com/recon/ge/Atlantic .kmz
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Ingesting dry air, pressures not lowering, and the attachment to the front is keeping 98L from developing today.
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342. Skyepony (Mod)
Quoting CybrTeddy:
FWIW the recon just passed directly over my house at 26 thousand feet.


Oh good someone saw it..I ran out to look.
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Interesting second system, models have been showing a low pressure system out here and I mentioned we'd have to watch this area for tropical development over the weekend on Friday.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
339. Skyepony (Mod)
If it wasn't so cloudy I could probably spot AF304 flying over.
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Quoting KeithInSoFL:


It is working now in Google Earth.


What feature of google earth are you using to see this?
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Did dey drop a sonde CT ?

: )
Member Since: July 3, 2005 Posts: 428 Comments: 129903
336. 7544
do we have a llc yet ?
Member Since: May 6, 2007 Posts: 0 Comments: 6874
At 17:32:30Z (first observation), the observation was 10 miles (16 km) to the NNW (335°) from Tampa, FL, USA.
At 17:42:00Z (last observation), the observation was 35 miles (56 km) to the SSW (207°) from Orlando, FL, USA.

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Quoting HurricaneDean07:
Wow, weird 3 recon planes in the air,
1 going into 98L
2 and 3 flying around in the gulf


Actually it looks like 4 aircraft... 302, 303, 304 are all in the GOM area with Teal 70 apparently in route to the blob east of FL
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FWIW the recon just passed directly over my house at 26 thousand feet.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Quoting Bonz:
God, the Weather Channel tropical update is useless. They did what, 15 seconds on this? Thanks for nothing.


I know, which is why I hate TWC. If you are looking for gardening tips, then it is fine.
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My son is flying to Beijing Tuesday. How will Ma-on affect flights?Looks like a huge storm
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330. Bonz
God, the Weather Channel tropical update is useless. They did what, 15 seconds on this? Thanks for nothing.
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Its not weird at all. 3 AF HH Teal Flights and a NOAA P-3 are all relevant atm.
Member Since: July 3, 2005 Posts: 428 Comments: 129903
Quoting SLU:


The GFS suggests development and carries it ENE ahead of 98L.


Thanks. Looks like things are heating up out there finally. Hopefully we'll have advantageous steering this year.
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Pretty surprised that the NHC states that this has changed little in organization when all surface observations, WINDSAT, ASCAT, and visible satellite imagery clearly show an increasingly more defined low level circulation and organizing low level structure. Would have placed the chances at around 50 to 60% for development into a tropical cyclone within the next 48 hours.
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Quoting AussieStorm:

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.
Wow... not often we get to dish it to the Doc.... lol... of course if this never makes it to TD... which I doubt... he'd be right, wouldn't he? LOL

Frankly, though, I don't think this is going to wait until Thursday to do something. More like within the next 48 seems a more legit. time frame for upgrade to TD or even TS... and while I seriously doubt we'll see more than that, I do think we'll get at least a TS out of it...
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315. Recon is still enroute.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Quoting KeithInSoFL:


It is working now in Google Earth.


Looks like pressures in the area are not falling, instead, they actually went up.

http://www.capeweather.com/buoy-data-florida.html
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Wow, weird 3 recon planes in the air,
1 going into 98L
2 and 3 flying around in the gulf
Member Since: October 3, 2010 Posts: 40 Comments: 4129
The HH should have some good data, but nothing suprising.
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Member Since: July 3, 2005 Posts: 428 Comments: 129903
320. SLU
Quoting AtHomeInTX:


Was wondering about that.


The GFS suggests development and carries it ENE ahead of 98L.
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Quoting KeithInSoFL:


It is working now in Google Earth.


YO! Thanks for the heads up... back to Google Earth
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Quoting HarryMc:


Same here... Tail No 304, operating west of Tampa


It is working now in Google Earth.
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Quoting HarryMc:


Same here... Tail No 304, operating west of Tampa


I just reloaded Google and all 3 missions are now showing
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Quoting Tazmanian:



its out now


Thanks, They should be able to clear things out for us, I am surprised at how conservative the NHC are being with this since it seems to me by looking at visible that this storm is exploding fast except for dry air intrusion of course but developing fast nevertheless.
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Recon turned back.... :(

1. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A BROAD AREA OF LOW
PRESSURE LOCATED ABOUT 125 MILES EAST OF MELBOURNE FLORIDA
HAVE CHANGED LITTLE IN ORGANIZATION OVER THE PAST SEVERAL HOURS.
UPPER-LEVEL WINDS HAVE BECOME A LITTLE MORE CONDUCIVE FOR
DEVELOPMENT TODAY...AND THIS SYSTEM HAS A MEDIUM CHANCE...40
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES LITTLE. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT
IS ENROUTE TO INVESTIGATE THE AREA LATER TODAY.

Member Since: October 3, 2010 Posts: 40 Comments: 4129
As long as this system is attached to the front, NHC will NOT classify it..it has to be an entity of its own
Member Since: August 19, 2006 Posts: 13 Comments: 16225
Quoting Goldenblack:
Hi all,

Lurking all year so far, but have been following along at times. I live just north of Tampa and have noticed on Google earth that the HH plane is on course to fly right over this area....too bad it is cloudy!


Back to lurking.....


lol
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Mission 01 into Second Suspect Area
1
AF304 - Air Force WC-130J
Updated on our site at:
17:38Z on Jul 17, 2011

-83.5333
28.1167
0
0.06265365604476392
0
248032.0323319686
relativeToGround

1

http://www.tropicalatlantic.com/recon/archiv e/2011/BB/URNT15/AF/01/map.kmz
onInterval
300





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Quoting Stormchaser2007:
LOL


40%


Conservative to a fault, I'd say. Could be a TS this time tomorrow.
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Hi all,

Lurking all year so far, but have been following along at times. I live just north of Tampa and have noticed on Google earth that the HH plane is on course to fly right over this area....too bad it is cloudy!


Back to lurking.....
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Quoting emcf30:
Is anyone seeing the recon on Googlearth into 98L ? I am only seeing the 2 non tasked missions going on in the Northern GOM South of Fl and South of TX / LA
















































Same here... Tail No 304, operating west of Tampa
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Why does Google show the HH going WNW
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I think 40% is right on! Have you looked at the 850mb vorticity and the attachment to the front? 98L has at least 12 or more like 24 hours before any real potential developement into a TD.
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Rain, Rain, Rain, over Pensacola today HOORAY! Interesting to ... it has circulation and is just hanging here unlike the usual storms that pass through.

Any weather expert care to comment? Anyway we needed the rain BAD!!
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Quoting CaneHunter031472:
When is the HH mission scheduled for?



its out now
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting CaneHunter031472:
When is the HH mission scheduled for?


Inbound now
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When is the HH mission scheduled for?
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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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