Little change to 90L

By: Dr. Jeff Masters , 13:33 GMT le 25 mai 2010

Share this Blog
2
+

The extratropical low pressure system (90L) approaching North Carolina has weakened some over the past 24 hours, and has a much reduced chance of developing into a subtropical storm. The National Hurricane Center (NHC) is giving 90L a less than 20% chance of developing into a depression or tropical/subtropical storm, and anticipates not writing any more special advisories on it. Last night's ASCAT pass saw a large area of 35 mph winds to the north and east of the center, and buoy 41048 to northeast of 90L's center was seeing sustained E winds of 31 mph, gusting to 36 mph this morning. Bermuda radar showing an area of moderate to heavy rain has now moved north of the island, and seas are running 10 - 15 feet in the outer waters of Bermuda today.


Figure 1. Visible satellite image of 90L and the Central American disturbance this morning.

Strong upper-levels winds out of the west are creating about 20 knots of wind shear over 90L, and the shear has been gradually decreasing over the past day. Visible satellite loops show that 90L has a well-defined surface circulation. The main thunderstorm activity is in a large curved band to the north and northeast of the center. This band is several hundred miles removed from the center, which is characteristic of subtropical storms. Sea surface temperatures are near 24°C today and will remain in the 23 - 24°C range the next two days. These relatively cool SSTs have hampered formation of much heavy thunderstorm activity, as has the presence of a large area of dry air to the west, as seen on water vapor satellite loops .

The system will move slowly towards the Southeast U.S. coast today, making its closest approach to the coast on Wednesday, when most of the models indicate the center will be 300 - 500 miles southeast of Cape Hatteras, North Carolina. All of the major models currently predict that 90L will not make landfall, but will move slowly eastward out to sea on Thursday, when a trough of low pressure moving across the Eastern U.S. picks up the storm. There presently isn't much to be concerned with about this storm, though Bermuda may get more heavy rain and high seas from the storm late this week as it moves out to sea. Wunderbloggers Weather456 and StormW have more on 90L.

Central American disturbance
An area of disturbed weather has developed just off the Pacific coast of Guatemala. The disturbance will move inland over Central America during the last half of the week, potentially bringing flooding rains to portions of Guatemala, El Salvador, Honduras, and Nicaragua. There is the potential for the disturbance to push into the Western Caribbean late this week and pose a threat to develop into a tropical depression. While there is high wind shear over the northern Caribbean, shear should be low enough to allow development should the disturbance stay in the southern reaches of the Caribbean. Any storm that develops in the Caribbean in the coming week would get steered to the northeast and will not pose a threat to the Gulf of Mexico.

Tornadoes rip through the Plains
The Storm Prediction Center logged 17 reports of tornadoes yesterday, with twisters reported in South Dakota, North Dakota, Nebraska, Oklahoma, and Texas. In addition, there were 158 hail reports and 126 reports of damaging winds. Fortunately, there were no deaths or injuries reported, and it was a good day for the Vortex2 tornado field research project. Former wunderblogger Mike Theiss caught up with a very picturesque tornado near Faith, South Dakota, and has posted some spectacular video of the tornado.


Figure 2. Large tornado near Faith, South Dakota on May 24, 2010 just misses hitting a church. Image credit: Mike Theiss, ultimatechase.com. Check out his spectacular video of the tornado.

I'll be back later today to discuss how a hurricane might affect the oil in the Gulf of Mexico.

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: 1067 - 1017

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38Blog Index

Quoting FIU2010:


no te pases conmigo, acerito. y como te atreves a corregir mi espanol impeccable,


Nosotros hablamos ingles y solo ingles. Nosotros no hablamos espanol, porque no sabemos. Yo se espanol, pero los muchacos no saben espanol. Comprendes? :)
Member Since: Posts: Comments:
Quoting nrtiwlnvragn:


Ahh...but. Subtropical cyclones have characteristics of both tropical and extratropical cyclones. Which ones from which. NWS directive states:

However, due to the lack of well-defined criteria for distinguishing subtropical from non-tropical lows, marginally-subtropical systems may be handled as non-tropical gale or storm centers in High Seas forecast products.

So again comes back to subjective judgement by the forecaster.


Ahh! which one from which?

Transition is the key word!

Subtropical cyclones don't form from tropical cyclones. Subtropical cyclones form from non-tropical systems/processes that become under the influence of tropical mechanisms thus acquiring tropical characteristics.


So we know who comes from who.
Member Since: Posts: Comments:
Quoting catastropheadjuster:

Go look at the riser know it's something that i haven't seen yet it's kinda weird. Has anyone looked at it lately?
sheri

Something is going on down there. I mean I am not no professional but something has changed.
Sheri
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
90E*

EP, 90, 2010052518, , BEST, 0, 111N, 889W, 20, 1007, DB, 34, NEQ, 0, 0, 0, 0, 1008, 160, 20, 0, 0, E, 0, , 0, 0, INVEST, D,


why are you posting data that is 6 hours old?
Member Since: 10 Mars 2010 Posts: 1 Comments: 7872
90E*

EP, 90, 2010052518, , BEST, 0, 111N, 889W, 20, 1007, DB, 34, NEQ, 0, 0, 0, 0, 1008, 160, 20, 0, 0, E, 0, , 0, 0, INVEST, D,
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
I could not in good conscience name the system as it is right now.



LOL LOL LOL




if i we re call there was a few storms last year that look like crap and they got name in fac a few of them had high wind shear and yet they still got name
Member Since: Posts: Comments:
Quoting mfaria101:
Is anyone else having problems viewing the live feed from the BP site? I cant get it in Ie or Firefox but it work a few hours ago.

Go look at the riser know it's something that i haven't seen yet it's kinda weird. Has anyone looked at it lately?
sheri
Member Since: Posts: Comments:
1058. Levi32
Quoting Weather456:
I think the NHC should stop naming subtropical systems, then there would be less confusion because we gonna get a couple more systems this year that will not get named and have debates over. In my opinion, if we are dealing with tropical prediction we should be concern more about purely tropical systems. And besides subtropical systems form from mid-latitude influences so should be kept out of tropical classifications.


That would be nice. Although some subtropical storms can become quite intense and pose a threat to life and property, I think it would be simpler for the NHC to not bother with them. They don't even really contribute to the season number, because the conditions in the tropics contributing to how active of a season we have usually has little to do with how many subtropical storms we get. To count them in the final season tally is misleading. I think the NHC should leave them alone, but post outlooks on them if they show potential to become fully tropical. For example, Andrea in 2007 looked to have that potential with the symmetric convection, and in a case like that I think the NHC should pay attention. Vince in 2005 was another good example.
Member Since: 24 novembre 2005 Posts: 635 Comments: 26684
Quoting FIU2010:
im back, all, he volvido, todos. rip 90L.
Volvido?

Don't you mean olvido or volver?
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
Quoting Weather456:


I know classification is subjective and we can see it even across regional agencies around the world. Therefore, we cannot always use the "weight" of a name to dictate what a system is. For example, 90L based on objective data or semi-objective data is subtropical but because it does not get a name should not be a reason or argument to think it was non-tropical all together.


Ahh...but. Subtropical cyclones have characteristics of both tropical and extratropical cyclones. Which ones from which. NWS directive states:

However, due to the lack of well-defined criteria for distinguishing subtropical from non-tropical lows, marginally-subtropical systems may be handled as non-tropical gale or storm centers in High Seas forecast products.

So again comes back to subjective judgement by the forecaster.
Member Since: Posts: Comments:
i like yours better!
Member Since: Posts: Comments:
Quoting Acemmett90:

whats the link for the navy site again

Link
Member Since: Posts: Comments:
Quoting Weather456:


For that to occur, we have to a high in the Central Atlantic that is not too far west as in 2008 and 2005 and not too far east as in 2006 and 2009.

A centralized high pressure ridge allows system to curve more towards the NW without ever going out to sea (east coast landfalls).

Now I am expecting a high pressure set-up similar to 2005 and 2008 based on similar conditions in April of all three years. Thus I am not expecting much east coast landfall above 30N this year. Now that does not exclude the area from landfalls, just a lower probability.


Also the highest pressure anomalies forecasted for the peak of the hurricane season favors 2008 and 2005 tracks.

thanks! that is the type of answer i was looking for. you explained in detail what we all should expect. very knowledgeable
Member Since: Posts: Comments:
I think the NHC should stop naming subtropical systems, then there would be less confusion because we gonna get a couple more systems this year that will not get named and have debates over. In my opinion, if we are dealing with tropical prediction we should be concern more about purely tropical systems. And besides subtropical systems form from mid-latitude influences so should be kept out of tropical classifications.
Member Since: Posts: Comments:
Quoting Levi32:


The NHC doesn't seem to think it has acquired that many tropical characteristics, and I myself would not name it yet based on how little convection it has around the center. I could not in good conscience name the system as it is right now. That may change tomorrow.


Yea. Last Night it weakened, but now it appears it's making a comeback.
Member Since: Posts: Comments:
1048. Levi32
Quoting Weather456:


Subtropical systems can have warm-cores, but its normally not as high as 100 mb as you said.


That's why it doesn't make sense. Hurricanes will often show up on 500mb charts as a low but 90L is far from that deep, and the low aloft must be a cold pocket, yet warm anomalies from AMSU are shown through the entire troposphere. I am inclined to believe some of that data may be wrong.
Member Since: 24 novembre 2005 Posts: 635 Comments: 26684
I expect the NHC wont even have a yellow circle on 90L before long, but I do think it will stay activated as an invest through Thursday
Member Since: 10 Mars 2010 Posts: 1 Comments: 7872
I'm out for a bit, Breakfast time.
had 3/4 inch of rain since 9am.

Now
55.4°F steady
Updated at 10:00 EST
Member Since: Posts: Comments:
1044. Levi32
Quoting Snowlover123:


How come it's not named?


The NHC doesn't seem to think it has acquired that many tropical characteristics, and I myself would not name it yet based on how little convection it has around the center. I could not in good conscience name the system as it is right now. That may change tomorrow.
Member Since: 24 novembre 2005 Posts: 635 Comments: 26684
1043. KEEPEROFTHEGATE (Mod)
Quoting AussieStorm:
Getting active.
90L


90E

93W


98S
6 days to go lets see how it all unfolds
Member Since: Posts: Comments:
1042. Drakoen
No more special feature in the TWD
Member Since: Posts: Comments:
1041. txjac
I'm watching it, viewing through IE8 ...its quite messy, I think that they are preparing the area for the top kill
Member Since: Posts: Comments:
1040. Patrap
BP

Live video link from the ROV monitoring the damaged riser


Currently obscured
Member Since: 3 juillet 2005 Posts: 426 Comments: 129093
Quoting Hurricanes101:
Its the battle of the Invests

How many of the 4 Invests get classified?

Which one gets classified 1st?

Which one in the end becomes the strongest?


Place your bets now


I think the ones in the Indian Ocean will get classified first. The one in the EPAC looks very disorganized right now, can't find a rotation. With 90L in the Atlantic, you can see at least a broad rotation. Not sure about it. Thought it would form, then not, now I'm not sure...:o
Member Since: Posts: Comments:
NAO might go positive briefly.

Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
Quoting Levi32:


It is not fully tropical, or the upper low would not exist above it. The AMSU data showing warm anomalies all the way through 100mb confuses me, but the upper low represents a cold pocket, not a warm pocket like you would find in a fully-tropical system. 90L is subtropical.


Subtropical systems can have warm-cores, but its normally not as high as 100 mb as you said.
Member Since: Posts: Comments:
1035. KEEPEROFTHEGATE (Mod)
Quoting Patrap:
IMO..


Invest Madness Overhype
by the time something real big comes along they will be poppin out there eyes and screaming uncontroled into there computers and talking nothing but gibberish
Member Since: Posts: Comments:
Is anyone else having problems viewing the live feed from the BP site? I cant get it in Ie or Firefox but it work a few hours ago.
Member Since: Posts: Comments:
back later, american idol finale :) (Vote for Lee)
Member Since: Posts: Comments:
1031. Patrap
Id Like to buy a vowel Vanna..
Member Since: 3 juillet 2005 Posts: 426 Comments: 129093
Quoting nrtiwlnvragn:


As I thought, another semi-subjective characteristic.


I know classification is subjective and we can see it even across regional agencies around the world. Therefore, we cannot always use the "weight" of a name to dictate what a system is. For example, 90L based on objective data or semi-objective data is subtropical but because it does not get a name should not be a reason or argument to think it was non-tropical all together.
Member Since: Posts: Comments:
Quoting Acemmett90:


in my opinion
Quoting MiamiHurricanes09:
In My Opinion

In My Opinion. :P
Member Since: Posts: Comments:
Quoting Patrap:
IMO..


Invest Madness Overhype


Hahahaha... funny... ;)
Member Since: Posts: Comments:
Its the battle of the Invests

How many of the 4 Invests get classified?

Which one gets classified 1st?

Which one in the end becomes the strongest?


Place your bets now
Member Since: 10 Mars 2010 Posts: 1 Comments: 7872
Quoting AussieStorm:

you mean the four I's


Oops... I didn't see the 4th one. :o)
Member Since: Posts: Comments:
1024. Patrap
IMO..


Invest Madness Overhype
Member Since: 3 juillet 2005 Posts: 426 Comments: 129093
Quoting Snowlover123:

The three Ts. Triple Tropical Trouble. Also Three "Ts as in Tropical Invests!" :)

you mean the four I's
Member Since: Posts: Comments:
Quoting Acemmett90:


in my opinion


Quoting MiamiHurricanes09:
In My Opinion


Thanks. :)
Member Since: Posts: Comments:
Quoting Snowlover123:


What exactly does IMO mean?
In My Opinion
Member Since: 2 septembre 2009 Posts: 130 Comments: 21194
Quoting Levi32:


It is not fully tropical, or the upper low would not exist above it. The AMSU data showing warm anomalies all the way through 100mb confuses me, but the upper low represents a cold pocket, not a warm pocket like you would find in a fully-tropical system. 90L is subtropical.


How come it's not named?
Member Since: Posts: Comments:

Viewing: 1067 - 1017

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38Blog 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.

Local Weather

Clear
53 ° F
Ciel dégagé