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

Share this Blog
0
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 502 - 452

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23Blog Index

502. xcool
98L MOVE TO SSE AT 10Mph jmo
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting clwstmchasr:


At the moment I agree. 1015mb doesn't warrant TD status. Need to see over the next 12 hours is the pressure does fall.


Down to 1013 mb according to the ATCF.
Member Since: July 8, 2005 Posts: 259 Comments: 24578
Spotters Report the Tornado has lifted for the moment

07/17/2011 0108 PM
4 miles SSE of New Rockford, Eddy County.
Tornado, reported by NWS storm survey.
Clear damage path from Highway 281 4s New Rockford through shelter-belt east of 281

Member Since: May 17, 2009 Posts: 2 Comments: 907
496. 7544
Quoting KEEPEROFTHEGATE:
POSS T.C.F.A.
INV98/XX/L
MARK
27.87N/77.97W


looks to be drifting further south ?
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Member Since: July 3, 2005 Posts: 428 Comments: 129902
Interesting to see the 30kt winds within the thunderstorms, but surface pressures are still very high. 98L still has some work to do.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
I'm sticking with my thought from 3 hours ago. They'll go 100% or just call it a TD now, even if it's not meeting the strictest definition of the term. This isn't some blob in the SW carib. It's too close to Florida.
Member Since: November 7, 2009 Posts: 0 Comments: 23
Quoting nymore:
Going from bad to worse for Eastern ND and western Minnesota tornado watch issued with mod. to high values. Tornadoes F2 and above moderate, severe wind high, 65 knts moderate, 2" plus hail high and these numbers have been rising all day
Been looking at this all day... :o(

Looking at 98L.... still got dmin to get through, still needing to get circulation closed up, still needing wind obs to support... I still say 12 hrs min before they call this. More like 18 imo.

But it's looking pretty good for a post-frontal something...
Member Since: Posts: Comments:
IF that 40MPH holds true....
Member Since: March 10, 2006 Posts: 0 Comments: 10804
98L continues to show signs of organization...I would not be surprised to see a depression after the recon is done. Thunderstorm activity is becoming more and more concentrated near the center and overall is looking impressive.
Member Since: Posts: Comments:
Quoting nymore:
A few reports of near baseball size hail


Been like that for weeks now up there. Got hit by some baseball size hail in Wyoming 3 weeks ago while driving from Denver to Rapid City. Luckily had just pulled over to change drivers. Was in the middle of nowhere on a two lane road. Few places to pull over.
Member Since: Posts: Comments:
POSS T.C.F.A.
INV98/XX/L
MARK
27.87N/77.97W
Member Since: Posts: Comments:
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)
Member Since: October 3, 2010 Posts: 40 Comments: 4129
484. ackee
Quoting IpswichWeatherCenter:


I don't think its set up structurally well enough to be a Tropical Depression. The Pressure is way too high for a storm like this.
agree but I have seen the NHC tag some systems TD that has look poorly before
Member Since: July 15, 2008 Posts: 0 Comments: 1376
Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 17th day of the month at 18:49Z
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: 08

Mandatory Data...

Observation Time: Sunday, 18:46Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 28.2N 77.6W
Location: 183 miles (295 km) between the NE and ENE (56°) from West Palm Beach, FL, USA.
Turbulence: Light
Conditions Along Flight Route: In the clear
Pressure Altitude: 180 meters
Flight Level Wind: From 120° at 23 knots (From the ESE at ~ 26.4 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 22°C
Flight Level Dew Point: 18°C
Weather (within 30 nautical miles): Thunderstorm(s)
Mean Sea Level Pressure (MSLP): 1016 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 120° at 30 knots (From the ESE at ~ 34.5 mph)

Remarks Section...

Surface Wind Speed (likely by SFMR): 29 knots (~ 33.4mph)
Member Since: Posts: Comments:
18:40:00Z 28.150N 77.917W 988.4 mb
(~ 29.19 inHg) 238 meters
(~ 781 feet) 1015.9 mb
(~ 30.00 inHg) - From 111° at 28 knots
(From the ESE at ~ 32.2 mph) 21.6°C
(~ 70.9°F) 19.0°C
(~ 66.2°F) 29 knots
(~ 33.3 mph) 31 knots*
(~ 35.6 mph*) 0 mm/hr*
(~ 0 in/hr*) 29.9 knots* (~ 34.4 mph*)
106.9%*
Member Since: July 3, 2005 Posts: 428 Comments: 129902
481. 7544
up now 35k hmmm
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Member Since: Posts: Comments:
Quoting Neapolitan:
ATCF says a 10-knot increase and a 1 mb drop.

AL, 98, 2011071718, , BEST, 0, 279N, 782W, 30, 1013, DB, 34, NEQ, 0, 0, 0, 0, 1016, 150, 50, 0, 0, L, 0, , 0, 0, INVEST, M,


Every little drop in pressure helps. :)
Member Since: Posts: Comments:
Seems to have put some time in towards organizing and the pressure is trending down, so they may go TD at their convenience.

98L Floater - Visible Loop



Check the boxes Fronts and MSLP
Member Since: July 3, 2005 Posts: 428 Comments: 129902
Quoting TxHurricanedude11:
Post 466:its because of a high to the north


How strong is the high pressure?
Member Since: Posts: Comments:
A few reports of near baseball size hail
Member Since: Posts: Comments:
35.0 knots (~ 40.2 mph)
Tropical Storm

Link

Somebody will have to translate. Just caught my eye.
Member Since: Posts: Comments:
Time: 18:34:00Z
Coordinates: 28.0833N 78.2167W
Acft. Static Air Press: 988.5 mb (~ 29.19 inHg)
Acft. Geopotential Hgt: 233 meters (~ 764 feet)
Extrap. Sfc. Press: 1015.3 mb (~ 29.98 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 110° at 32 knots (From the ESE at ~ 36.8 mph)
Air Temp: 22.1°C (~ 71.8°F)
Dew Pt: 18.5°C (~ 65.3°F)
Peak (10s) Flt. Lvl. Wind: 32 knots (~ 36.8 mph)
SFMR Peak (10s) Sfc. Wind: 34 knots* (~ 39.1 mph*)
SFMR Rain Rate: 0 mm/hr* (~ 0 in/hr*)
(*) Denotes suspect data
Member Since: April 23, 2011 Posts: 104 Comments: 14873
18:33:30Z 28.067N 78.233W 988.5 mb
(~ 29.19 inHg) 232 meters
(~ 761 feet) 1015.3 mb
(~ 29.98 inHg) - From 109° at 32 knots
(From the ESE at ~ 36.8 mph) 22.1°C
(~ 71.8°F) 18.4°C
(~ 65.1°F) 32 knots
(~ 36.8 mph) 35 knots
(~ 40.2 mph) 1 mm/hr
(~ 0.04 in/hr) 35.0 knots (~ 40.2 mph)
Tropical Storm 109.4%
Member Since: April 14, 2007 Posts: 8 Comments: 5169
470. Skyepony (Mod)
Just got a beach report from Indialantic.. It's rough out there & the upwelling is gone, all warm again.
Member Since: August 10, 2005 Posts: 226 Comments: 39438
Time: 18:35:30Z
Coordinates: 28.0833N 78.1667W
Acft. Static Air Press: 988.5 mb (~ 29.19 inHg)
Acft. Geopotential Hgt: 233 meters (~ 764 feet)
Extrap. Sfc. Press: 1015.6 mb (~ 29.99 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 109° at 30 knots (From the ESE at ~ 34.5 mph)
Air Temp: 21.8°C (~ 71.2°F)
Dew Pt: 18.7°C (~ 65.7°F)
Peak (10s) Flt. Lvl. Wind: 32 knots (~ 36.8 mph)
SFMR Peak (10s) Sfc. Wind: 33 knots (~ 37.9 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)

Ok - so it has TD winds, is it structured well enough though?
Member Since: Posts: Comments:
468. JLPR2
Even if it isnt a TC Florida should keep a close eye on it cause it is packing decent winds.

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)
Member Since: Posts: Comments:
ATCF says a 10-knot increase and a 1 mb drop, reflecting what recon is finding.

AL, 98, 2011071718, , BEST, 0, 279N, 782W, 30, 1013, DB, 34, NEQ, 0, 0, 0, 0, 1016, 150, 50, 0, 0, L, 0, , 0, 0, INVEST, M,
Member Since: Posts: Comments:
Quoting ackee:
98L does have TD winds will the NHC upgrade or wait for it to get more convection


I don't think its set up structurally well enough to be a Tropical Depression. The Pressure is way too high for a storm like this.
Member Since: Posts: Comments:
464. Skyepony (Mod)
28.067N 78.233W is the closest to a center there is with 1015.3mb low, center is not closed yet.
Member Since: August 10, 2005 Posts: 226 Comments: 39438
Quoting nymore:
Pcoladan that is a nasty looking cell in nd had a tornado warning with for over 2.5 hours


Been watching that. Flood affected areas can't seem to get a break.
Member Since: Posts: Comments:
462. xcool
i say waiting.
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Looks like it headed in the right direction. NHC might issue a special tropical disturbance statement later today given the close proximity and need for marine interests to keep a close eye on it.....JMO.
Member Since: Posts: Comments:
Quoting HurricaneDean07:
Latest SFMR show 37.9 Winds, near TS winds, but dont expect a TD or TS for another 6 to 12 hours.


Is it rain affected though HurricaneDean07?

I just looked and:
Time: 18:32:00Z
Coordinates: 28.0667N 78.3W
Acft. Static Air Press: 985.7 mb (~ 29.11 inHg)
Acft. Geopotential Hgt: 261 meters (~ 856 feet)
Extrap. Sfc. Press: 1015.8 mb (~ 30.00 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 103° at 29 knots (From the ESE at ~ 33.3 mph)
Air Temp: 21.5°C (~ 70.7°F)
Dew Pt: 18.4°C (~ 65.1°F)
Peak (10s) Flt. Lvl. Wind: 30 knots (~ 34.5 mph)
SFMR Peak (10s) Sfc. Wind: 33 knots* (~ 37.9 mph*)
SFMR Rain Rate: 0 mm/hr* (~ 0 in/hr*)
(*) Denotes suspect data
Member Since: Posts: Comments:
Pcoladan that is a nasty looking cell in nd had a tornado warning with for over 2.5 hours
Member Since: Posts: Comments:
458. ackee
98L does have TD winds will the NHC upgrade or wait for it to get more convection
Member Since: July 15, 2008 Posts: 0 Comments: 1376
Quoting HurricaneDean07:
Latest SFMR show 37.9 Winds, near TS winds, but dont expect a TD or TS for another 6 to 12 hours.


That data is listed as suspect.
Member Since: Posts: Comments:
Quoting TxHurricanedude11:

but thats not affecting at all
Look at the NW quadrant and see what it is absorbing.
Member Since: October 28, 2010 Posts: 0 Comments: 65
Quoting Stormchaser2007:


Impressive, really beginning to wrap around. Is RECON going out today?
Member Since: Posts: Comments:
Latest SFMR show 37.9 Winds, near TS winds, but dont expect a TD or TS for another 6 to 12 hours.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Time: 18:32:00Z
Coordinates: 28.0667N 78.3W
Acft. Static Air Press: 985.7 mb (~ 29.11 inHg)
Acft. Geopotential Hgt: 261 meters (~ 856 feet)
Extrap. Sfc. Press: 1015.8 mb (~ 30.00 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 103° at 29 knots (From the ESE at ~ 33.3 mph)
Air Temp: 21.5°C (~ 70.7°F)
Dew Pt: 18.4°C (~ 65.1°F)
Peak (10s) Flt. Lvl. Wind: 30 knots (~ 34.5 mph)
SFMR Peak (10s) Sfc. Wind: 33 knots* (~ 37.9 mph*)
SFMR Rain Rate: 0 mm/hr* (~ 0 in/hr*)
strongest so far
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 17th day of the month at 18:33Z
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: 07

Mandatory Data...

Observation Time: Sunday, 18:32Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 28.1N 78.3W
Location: 142 miles (229 km) to the E (90°) from Melbourne, FL, USA.
Turbulence: Light
Conditions Along Flight Route: In the clear
Pressure Altitude: 210 meters
Flight Level Wind: From 100° at 31 knots (From the E at ~ 35.6 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 22°C
Flight Level Dew Point: 18°C
Weather (within 30 nautical miles): Thunderstorm(s)
Mean Sea Level Pressure (MSLP): 1016 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 80° at 30 knots (From the E at ~ 34.5 mph)

Remarks Section...

Surface Wind Speed (likely by SFMR): 31 knots (~ 35.7mph)
Member Since: Posts: Comments:

Viewing: 502 - 452

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23Blog Index

Top of Page

About

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

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron