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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602. Skyepony (Mod)
There it is recon found 1010mb, solid west wind, for a moment.. COC ~27.583N 78.267W
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Good, if you come to Texas anytime soon, bring that rain with you please, and thank you... actually got to see rain on the windshield of the car when i was on my vacation(New Mexico/Colorado). those monsoonal showers come in handy over there.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Recent data may indicate a TD, flight level winds at least higher than SFMR and 1010 mb.
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599. ackee
I think the NHC needs to issue a special disturbance statement and up 98L chance to 60 percent dont think this should be upgraded to an TD until sometime tonight or the next 24 hours
Member Since: July 15, 2008 Posts: 0 Comments: 1373
Significant pressure drops reported by Hurricane Hunters down to 1010 mb.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Eh if convection starts to fire again in the center i say TD or TS

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recon is finding lower pressures now... down to 1014 mb and not at center yet
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Quoting nrtiwlnvragn:


I haven't seen any data come in from any synoptic flights. There were two other Air Force planes out earlier, but they appeared to be training missions. Only two dropsonde reports have come in, one from the invest mission and one from one of the other Air Force planes.


I stand corrected. I thought that they were out there sampling the atmosphere.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Member Since: July 3, 2005 Posts: 426 Comments: 128668
Fleet Weather Center Norfolk Tropical Feed
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (FWC-N CDO) from Fleet Weather Center Norfolk Virginia. Published on Sun, Jul 17, 2011.

As of Sun, 17 Jul 2011 19:30:02 GMT
Member Since: July 15, 2006 Posts: 174 Comments: 54434
Classic North Dakota Tornado Signature. Bean shape on the southern flank where the tornado is on the ground.
Member Since: May 17, 2009 Posts: 2 Comments: 904
Not looking like there's much wind from the south on the east side.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
Quoting cchsweatherman:
Something to keep in mind is that while there is one flight investigating Invest 98L, there are two others sampling the atmosphere around the system to give the models later on a better handle of the upper and mid level air patterns.


I haven't seen any data come in from any synoptic flights. There were two other Air Force planes out earlier, but they appeared to be training missions. Only two dropsonde reports have come in, one from the invest mission and one from one of the other Air Force planes.
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Northern portion of the circulation looks decent.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Quoting VirgilSolozzo:
Waiting to get Knabb off the phone. He's frantically begging his old buds to not upgrade here and now, so he doesn't look like a fool.


Now thats funny but "So True"

Quoting HurricaneDean07:
Hey Taco, how are you?
:o)


Doing Good but kinda wanted to go fishing but rained out for the 2nd day.... But again not complaining though we need this 5" today to go with the 2 1/2 we got yesterday :o)

Good to see ya on today, How are You my Friend?

Taco :o)
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Quoting nymore:
And a moderate risk for severe weather goes up ND and MN


it's missed Fargo, so far. We need a good T-storm here, maybe it will suck up some of this humidity and turn it into rain.
Member Since: August 29, 2008 Posts: 0 Comments: 324
Tropical/Subtropical cyclones which initially form in this general position east of Florida almost always seem to end up moving northeast (away from us). At least, this is what I have noticed over the last several years. I sure wouldn't mind a weak, gusty tropical storm that brings rain and harms nobody.
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Quoting Dakster:
I am sure someone is monitoring the Navy site. Please post if they do a "rename".




2011 Storms
All Active Year


Atlantic
98L.INVEST

East Pacific
94E.INVEST

Central Pacific

West Pacific
08W.MA-ON

Indian Ocean

Southern Hemisphere
Member Since: July 15, 2006 Posts: 174 Comments: 54434
Quoting PakaSurvivor:


Thanks Pat. I remember a friend talking about Hurricane Danny in 1997 caught everyone by surprise on the Panhandle and Mobile, AL and was wondering if this is the same type setup?



I member it well,,


check out that Highest rain total,,something dosent have to be a cat 5 to do the nasty on a locale.


A broad mid-tropospheric trough over the southeastern United States spawned an area of convection over the lower Mississippi River Valley on July 13, and drifted southward towards the warm waters of the Gulf of Mexico. As it moved into the Gulf of Mexico, a weak and isolated surface low pressure area formed off the coast of Louisiana. The circulation in the system steadily expanded, and initially the surface winds and convection were intermittent. On July 16, deep convection increased and organized near the center, and oil rigs and surface buoys reported surface winds of 30 mph (50 km/h). Based on the observations, it is estimated the system developed into Tropical Depression Four on July 16 while about 150 miles (240 km) south of the southwestern Louisiana coastline.
Hurricane Danny seen after passing over Southeastern Louisiana

The depression slowly organized for the next day, as it drifted to the northeast. On July 17, the rate of organization and development of deep convection increased considerably, and the depression strengthened into Tropical Storm Danny later that day. From the night of July 17 through July 18, Danny quickly developed deep convection and banding features in the favorable environment of the Gulf of Mexico, and reached hurricane status later on July 18. Located between two high pressure systems, Danny continued its unusual July track to the northeast, and crossed over southeastern Louisiana near the Mississippi River Delta. A small storm, Danny continued to strengthen after reaching the coastal waters off Mississippi on the night of July 18, and attained a peak of 80 mph (130 km/h) early on July 19. The hurricane force winds, however, were confined to the eyewall. After stalling near the mouth of Mobile Bay on July 19, Hurricane Danny turned to the east, and made its final landfall near Mullet Point, Alabama later that day
Member Since: July 3, 2005 Posts: 426 Comments: 128668
Quoting VirgilSolozzo:
Waiting to get Knabb off the phone. He's frantically begging his old buds to not upgrade here and now, so he doesn't look like a fool.


I don't know, but if it was me, I better eat a crow at the NHC than having to surprise people with a sudden tropical storm. This close to land and whith these conditions, I would not dare being conservative. Dang at least give it a higher perentage so we know they are not sleeping or on lunch break.
Member Since: August 1, 2007 Posts: 0 Comments: 182
582. Skyepony (Mod)
Quoting AllStar17:


?


Cross through the center again...
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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.


Many places have laid off their veteran meteorologists because it's cheaper to hire an attractive 28yo bimbo to read off the model data.

Our local NBC affiliate fired our local well-loved meteorologist "too tall" Tom Szymanski because it was cheaper to have a young rookie just regurgitate the models.

I really miss Too Tall Tom, he is a brilliant meteorologist and has a very intuitive understanding of out local winter weather.
Member Since: August 29, 2008 Posts: 0 Comments: 324
Hey Taco, how are you?
:o)
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Quoting Skyepony:


Didn't look closed at the surface last recon pass. They are about to hit it again..


You're jumping the gun since they've only investigated the northern portion of the disturbance.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting Skyepony:


Didn't look closed at the surface last recon pass. They are about to hit it again..


Awesome point. Question, how strenght will influence steering then? My take is that the weaker the more westerly track it will take and the stronger it is, the more to the north.
Member Since: August 1, 2007 Posts: 0 Comments: 182
Quoting CaneHunter031472:
Forgive my ignorance but I really think that this is already a TD if not a TS. What is the NHC waiting for?
Waiting to get Knabb off the phone. He's frantically begging his old buds to not upgrade here and now, so he doesn't look like a fool.
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Quoting Patrap:


In the Tropics and esp the GOM, I never rule out a lingering Low with convection heading to warm ,tepid SST's.

The Atmosphere has a LOT of extra "Oomph" to offer as it trends towards chaos given a opportunity this time of year forward thru October and beyond.


Thanks Pat. I remember a friend talking about Hurricane Danny in 1997 caught everyone by surprise on the Panhandle and Mobile, AL and was wondering if this is the same type setup?
Member Since: September 20, 2010 Posts: 0 Comments: 235
Quoting cchsweatherman:
Something to keep in mind is that while there is one flight investigating Invest 98L, there are two others sampling the atmosphere around the system to give the models later on a better handle of the upper and mid level air patterns.


What are your thoughts on a possible track?
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573. 7544
Quoting taco2me61:


I'm going to say

"B"

And from what I'm seeing on radar it looks to be moving SSE at 5 MPH....

Taco :o)


b also cause its getting closer to land but still may move away to the ne
Member Since: May 6, 2007 Posts: 0 Comments: 6858
I am sure someone is monitoring the Navy site. Please post if they do a "rename".
Member Since: March 10, 2006 Posts: 0 Comments: 10469
Something to keep in mind is that while there is one flight investigating Invest 98L, there are two others sampling the atmosphere around the system to give the models later on a better handle of the upper and mid level air patterns.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting Skyepony:


Didn't look closed at the surface last recon pass. They are about to hit it again..


?
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Plus. I want to see model run consistency before I call a fish or land falling storm.
Member Since: March 10, 2006 Posts: 0 Comments: 10469
Observed at: Toronto Pearson Int'l Airport
Date: 3:00 PM EDT Sunday 17 July 2011
Condition: Partly Cloudy
Pressure: 30.04 inches
Tendency: falling
Visibility: 15 miles
Air Quality Health Index: 5

Temperature: 94.3°F
Dewpoint: 64.4°F
Humidity: 37 %
Wind: W 15 mph
Humidex: 105
Member Since: July 15, 2006 Posts: 174 Comments: 54434
Its gonna be a close call on it,,they have the conn,so I always defer to the Pro's..

Based on Winds and a trending down of pressure almost a given seems, TD is my guess.




Member Since: July 3, 2005 Posts: 426 Comments: 128668
564. Skyepony (Mod)
Quoting CaneHunter031472:
Forgive my ignorance but I really think that this is already a TD if not a TS. What is the NHC waiting for?


Didn't look closed at the surface last recon pass. They are about to hit it again..
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Quoting ackee:
when do u think 98L will be a TD

A 5PM
b 11pm
c 24 hours
D 48 HOURS
E 72 HOURS


I'm going to say

"B"

And from what I'm seeing on radar it looks to be moving SSE at 5 MPH....

Taco :o)
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Quoting CaneHunter031472:
Forgive my ignorance but I really think that this is already a TD if not a TS. What is the NHC waiting for?


Slide rules and Pencils?
Member Since: July 3, 2005 Posts: 426 Comments: 128668
SOMETHING HAS LEFT AFRICA OVER WATER NOW KEEP WATCH

Member Since: July 15, 2006 Posts: 174 Comments: 54434
Time: 18:33:30Z
Coordinates: 28.0667N 78.2333W
Acft. Static Air Press: 988.5 mb (~ 29.19 inHg)
Acft. Geopotential Hgt: 232 meters (~ 761 feet)
Extrap. Sfc. Press: 1015.3 mb (~ 29.98 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 109° at 32 knots (From the ESE at ~ 36.8 mph)
Air Temp: 22.1°C (~ 71.8°F)
Dew Pt: 18.4°C (~ 65.1°F)
Peak (10s) Flt. Lvl. Wind: 32 knots (~ 36.8 mph)
SFMR Peak (10s) Sfc. Wind: 35 knots (~ 40.2 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)
(*) Denotes suspect data

I suspect it will be upgraded to 35mph TD/ possible TS Bret
Member Since: April 29, 2007 Posts: 0 Comments: 7932
Quoting CaneHunter031472:
Forgive my ignorance but I really think that this is already a TD if not a TS. What is the NHC waiting for?


Hurricane Hunters have only gone through northern part of the system. The Hurricane Hunters still have to cross through the system and confirm a closed surface circulation before any update.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Some of those storms in ND and MN nearing 55,000 feet and growing rapidly
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Quoting neutralenso:
The Track i think 98L will take is what the CLIP 5 model is showing. check it out tell me if you agree and tell me what model track you think 98L will take
you do know the CLIP is based on statistics, not current conditions...hence, I would not use that as a guidance model.
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Quoting cchsweatherman:
Hurricane Hunters running their classic X pattern now. So far, so good this mission with several solid tropical depression force winds and even a tropical storm force wind reading. Also wind pattern so far so good for a closed circulation.


North side certainly coherent with a good circulation, interesting to see if the south side has westerlies.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
if 94E were to parallel the central american coast(not likely) then we wont see Dora, this is because that means it would be attatched to the ITCZ, but seriously Dora probably on the way in the EPAC in the next day and a half.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
553. Skyepony (Mod)
Quoting FLdewey:


Just took it on the boardwalk in Indialantic.

5th & A1A


Did you see recon fly over? I thought I heard it just a touch south of me. The clouds are piled up just inland.
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552. 7544
Quoting jasonweatherman2011:
FISH STORM!!!!!


tada tada very typical lol
Member Since: May 6, 2007 Posts: 0 Comments: 6858

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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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