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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Be back later; we are going to need recon data to try and figure out where a possible coc might be trying to form; a little hard to tell at the moment for me anyway and whether it is further north or south in the disturbance.
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Pre Bret looking very nice. Getting the cyclone look to it. Very interesting indeed..... wonder what this baby has up its sleeve
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Quoting nrtiwlnvragn:
Recent ASCAT, confusing since it shows some clockwise winds on the west side.




Visible satellite imagery definitely doesn't match that.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting emcf30:

Not unless I am missing something, which I might add could be a possibility, I agree with you 100 percent.


Does make ya wonder what they're seeing that we're not.
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POSS T.C.F.A.
XX/INV/98L
MARK
27.77N/77.77W
Member Since: July 15, 2006 Posts: 178 Comments: 56059
Quoting cchsweatherman:
Really having a hard time believing the computer models at this time with this system as there is definite ridging building to the north and expanding southward in time.



Given the building ridge, I really don't understand or see an escape route to the north at all. All that I can see is a general west to southwest motion with this system in time into the Gulf of Mexico.

Not unless I am missing something, which I might add could be a possibility, I agree with you 100 percent.
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Recon still go, what does the bold mean however?


000
NOUS42 KNHC 171615
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1215 PM EDT SUN 17 JULY 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 18/1100Z TO 19/1100Z JULY 2011
TCPOD NUMBER.....11-047

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA
FLIGHT ONE -- TEAL 72
A. 18/1800Z
B. AFXXX 0302A CYCLONE
C. 18/1500Z
D. 28.0N 79.5W
E. 18/1700Z TO 18/2300Z
F. SFC TO 10,000 FT

FLIGHT TWO -- TEAL 73
A. 19/0600Z
B. AFXXX 0402A CYCLONE
C. 19/0300Z
D. 28.5N 79.5W
E. 19/0500Z TO 19/1100Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 12-HRLY
FIXES WHILE SYSTEM REMAINS A THREAT.
3. REMARK: FLIGHT SCHEDULED FOR 18/1800Z WILL CONVERT TO AN
LOW-LEVEL INVEST MISSION IF THE FLIGHT SCHEDULED FOR
17/0600Z IS CANCELLED.
Member Since: July 8, 2005 Posts: 259 Comments: 24575
Recent ASCAT, confusing since it shows some clockwise winds on the west side.








Link
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Morning Gro.

Large flock of Seagulls to your NNE


Sorry, NE, still got that twitch from yesterday and hit two N's
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Quoting muddertracker:
I know Levi is probably still waking up...but I need a "mischief" scale rating on 98L!


Lol. Me too. :)
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Wow, got on not expecting much this morning, and look what i find! 98L looking very impressive this Morning, was going to do a poll, but i forget ive handed that job off to Tropicalanalysts... Although i do believe that it will be upped in more of the lines of 50 or 60% looking much more impressive, and recon will no doubt fly into this invest, time is on 98L's side, so interesting to wait and see what recon finds.
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91. JRRP
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Could the BAMM actually be right for once?
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting Hurricanes101:


I think he was right, about 30 miles west; the system is only about 110 miles off the coast of Melbourne


Here is the general distance of the western edge of the GS from shore off the coast of various SOFL locations fom one of the local fishing blogs down there:

Ocean Ridge ICWW
Distance: 2.56 miles N
Location: 26.5267° -80.0533°

South Delray Beach ICWW
Distance: 3.02 miles S
Location: 26.4467° -80.0650°

Lake Worth Boynton Beach
Distance: 4.04 miles N
Location: 26.5483° -80.0533°

Yamato ICWW
Distance: 6.04 miles S Location: 26.4033° -80.0700°

Lake Wyman ICWW
Distance: 8.33 miles S Location: 26.3700° -80.0700°

Lake Worth Pier Atlantic Ocean FL
Distance: 8.56 miles N Location: 26.6117° -80.0333°

Boca Raton Lake Boca Raton
Distance: 10.20 miles S Location: 26.3433° -80.0767°

Lake Worth West Palm Beach Canal
Distance: 10.73 miles N Location: 26.6450° -80.0450°

Deerfield Beach Hillsboro River
Distance: 12.30 miles S Location: 26.3133° -80.0817°

Measurements are approximate and do not represent actual travel distances.


Link
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I know Levi is probably still waking up...but I need a "mischief" scale rating on 98L!
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IMO, 98L is organizing a little further eastward along 78.2W
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Really having a hard time believing the computer models at this time with this system as there is definite ridging building to the north and expanding southward in time.



Given the building ridge, I really don't understand or see an escape route to the north at all. All that I can see is a general west to southwest motion with this system in time into the Gulf of Mexico.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
~ 5 minutes to recon takeoff
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting wxhatt:


yes it will hit cape hatteras


says the guy who lives in Cape Hatteras lol
Member Since: March 10, 2010 Posts: 1 Comments: 7874
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wow 98 is starting to get the toilet bowl look
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Quoting jasonweatherman2011:
I think L98 might be trying to form some low level bands and getting better looking to!! i see a new storms pop up right in the center!! lets hope its go out to sea because a little storm like this will get going fast if the wind shear go down!!


yes it will hit cape hatteras
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98L continues to loose lattitude. I think the modules will shift slightly left in the next run.
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I think it will hit Cape Hatteras
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http://www.ndbc.noaa.gov/station_page.php?station=4 1010 Water temps @ this buoy 83.1 Far.
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Quoting weathermanwannabe:


Correct; the Gulf Stream runs just off the Florida coast in this part of the State so 98L is still East of it at this point; I would estimate about 75-100 miles East of it.


I think he was right, about 30 miles west; the system is only about 110 miles off the coast of Melbourne
Member Since: March 10, 2010 Posts: 1 Comments: 7874
severe thunderstorm watch issued for me already this is not good
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~15 minutes till recon takeoff
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting islander101010:
it really not directly over the gulf stream needs to move west 30 miles west


Correct; the Gulf Stream runs just off the Florida coast in this part of the State so 98L is still East of it at this point; I would estimate about 75-100 miles East of it.
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Quoting hurricanehunter27:
I think L98 might be trying to form some low level bands.


You would indeed be correct. You can see low level inflow in the northeast quadrant coming into the storm and more curvature in the cloud structure around the disturbance.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Invest 98L appears to be undergoing evident organization this morning as both surface observations and RGB satellite imagery show a more defined low level circulation developing. In addition, convection has been on the increase including a new intense thunderstorm right over the developing circulation. If surface pressures lower throughout the day, then we could indeed have our next tropical depression and possibly even Tropical Storm Bret considering the numerous gale force winds detected on the most recent WINDSAT posted in comment 15.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
We need this thing to stay weak , drift slightly over the east coast of Florida , RAIN !
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Quoting hurricanehunter27:
I think L98 might be trying to form some low level bands.



I thought that myself so am happy to see that someone else is seeing that. I'm totally untrained so I dont trust my own impressions
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The weaker 98L stays the farther W it will go over time.
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Quoting CanesfanatUT:
When is recon scheduled to take off in EDT? Thanks


25 minutes.
Member Since: July 8, 2005 Posts: 259 Comments: 24575
I think L98 might be trying to form some low level bands.
Member Since: July 22, 2010 Posts: 1 Comments: 3852
it really not directly over the gulf stream needs to move west 30 miles west
Member Since: September 11, 2010 Posts: 1 Comments: 5002
Quoting hurricanehunter27:

If this gets into the GOM and has 72 hours or more in the GOM and enters as a TD or TS how strong do you guys think it will get?


There is only the BAM deep taking it into the Gulf it seems. Seems unlikely, no?
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Hi-res loop

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Quoting xcool:
damm gom sst dam

If this gets into the GOM and has 72 hours or more in the GOM and enters as a TD or TS how strong do you guys think it will get?
Member Since: July 22, 2010 Posts: 1 Comments: 3852
i'd be surprised if they dont fly looks like to me a tropical cyclone is being born hope it stays offshore e cen fl.
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Quoting CanesfanatUT:
When is recon scheduled to take off in EDT? Thanks


12:15
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Quoting xcool:
damm gom sst dam
Dont forget about the low darn wind shear and low darn pressures! If the GOM stays like this in Late Aug/Sept, get the plywood out!!
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Link


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When is recon scheduled to take off in EDT? Thanks
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98L looking to surprise some people, I think. BAM still taking it into the gulf?
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Last few frames on this loop show it spinning like a top. And on the last frame a little 'dimple' appears pretending to be an eye. Starting to get cute.


Link
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damm gom sst dam
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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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