Little change to 90L

By: Dr. Jeff Masters , 1:33 PM GMT on May 25, 2010

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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

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Quoting Stormchaser2007:


True.

An area of vort spins off the main circulation, but these runs dont even bring it over CA.
The GFS 18z shows that solution. It has the stronger 90E in the EPAC while a piece of its energy is just east of Belize.

GFS 18z 90 Hours.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
Did the Gulf stream separate lol? Take a look at this graph:


Giant Eddy broke off, right before the oil moved towards the keys. An act of god perhaps? (though I'm not trying to start a religious debate on the blog)
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Quoting StSimonsIslandGAGuy:
I had to do it tazmanian :)

90L is actually about 180 miles closer than it was 24 hours ago, and our pressure in the past 24 hours has fallen. From 1014.7 mb to 1014.5 mb. I need to get the spare oxygen tanks.


dont forget your plywood lol
Member Since: March 10, 2010 Posts: 1 Comments: 7814
Quoting Hurricanes101:


Yea I dont think its 90E itself that gets into the Caribbean, but a piece of energy from it.

It is only one model run, for all we know the next run they will all switch back to the Caribbean again


True.

An area of vort spins off the main circulation, but these runs dont even bring it over CA to complete that process.
Member Since: June 9, 2007 Posts: 4 Comments: 15920
.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1259. pottery
Quoting MiamiHurricanes09:
Yup.
Thanks. Very stupid system....
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Quoting Stormchaser2007:
Looks like 99% of the ATCF models for 90E do not take it into the Caribbean.
True. But you can't trust the first few model runs on an invest, wait another 18 hours or so and then pay attention to them.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
I havent looked at any weather today...way to busy at work. Trying to catch up on all the fun. Looks like I missed how to ignore myself. Maybe that is a good thing from time to time.
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Quoting Stormchaser2007:
Looks like 99% of the ATCF models for 90E do not take it into the Caribbean.


Yea I dont think its 90E itself that gets into the Caribbean, but a piece of energy from it.

It is only one model run, for all we know the next run they will all switch back to the Caribbean again
Member Since: March 10, 2010 Posts: 1 Comments: 7814
Quoting FIU2010:



Yes, that was exactly what i was making reference to, thank you so much. so i guess that doesn't spell out good news for us, now, does it? :(. that would also allow for rapid intensification of storms?


If the atmospheric and thermodynamic environment are favorable, possibly.
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1253. Levi32
Quoting FIU2010:
a question for either 456 or levi, or for both of them. alright, gentlemen, what do those low pressure anomalies that I see over the southeast and the carib. during the months of july, aug. and sept mean for us? Above all, why do i see the lowest pressure readings over the state of florida, what does that mean for floridians during this year's hurricane season, above all, for the peak months? Thanks, guys.


The lowest pressures are not centered over Florida on most of the seasonal forecasts...just thought I'd point that out lol.

The axis of below-normal pressures forecasted over the Caribbean, Bahamas, and Gulf of Mexico foretell an above-average hurricane season, as both myself and 456 have indicated in our hurricane outlooks this year, found on our respective blogs.

The lower pressures, combined with higher pressures to both the north and south, act to focus convergence over the southwest Atlantic basin, increasing precipitation and heat buildup. The lower pressures over the Caribbean combined with higher than normal pressures over Columbia act to weaken the Columbian heat low, which results in slower easterly trade winds across the Caribbean. This allows more air to pile up in the western Caribbean, further increasing convergence and allowing tropical waves/disturbances to amplify and develop.

This is a graphic from my hurricane season outlook illustrating these points.

Member Since: November 24, 2005 Posts: 635 Comments: 26652
Quoting HaboobsRsweet:
On a side note we got rocked on the coast today. I wish I had my camera. The clouds were awesome. Looked like tidal waves. 2 inch hail reported by the border also. Turbulence had to be real high. About time the sea breeze fired up. two massive outflows converged together over LA also.


Those same outflow boundaries generated 35 kt wind gusts in my area, along some of the most intense cloud-to-ground lightning I've seen in quite awhile. We also, I would estimate, received around a half an inch of rain within just 30 minutes. The parking lot at Wal Mart in Gonzales was flooded almost up to the ankles.
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Quoting pottery:
If 90E gets into the west atl, does it become 91L?
Yup.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Never mind.
Member Since: June 9, 2007 Posts: 4 Comments: 15920
Quoting Stormchaser2007:
Looks like 90L is going to pop some convection near the center tonight.

Really moistened the low up.

Are you lying? lol, I don't think 90L is going to do anything, looks pretty eh to me.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1248. pottery
If 90E gets into the west atl, does it become 91L?
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Quoting StSimonsIslandGAGuy:
But sirs! It's moving west. IT'S MOVING WEST!!!!!




are you JFV???



THIS KINDING
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On a side note we got rocked on the coast today. I wish I had my camera. The clouds were awesome. Looked like tidal waves. 2 inch hail reported by the border also. Turbulence had to be real high. About time the sea breeze fired up. two massive outflows converged together over LA also.
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Looks like 90L is going to pop some convection near the center tonight.

Really moistened the low up.

Member Since: June 9, 2007 Posts: 4 Comments: 15920
buy 90L now we turn too 90E
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1242. xcool
WHXX01 KMIA 260057
CHGE77
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0057 UTC WED MAY 26 2010

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

EAST PACIFIC OBJECTIVE AIDS FOR

DISTURBANCE INVEST (EP902010) 20100526 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
100526 0000 100526 1200 100527 0000 100527 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 11.2N 89.1W 12.0N 89.5W 13.2N 90.4W 13.9N 91.3W
BAMD 11.2N 89.1W 11.3N 90.0W 11.9N 91.1W 12.7N 92.4W
BAMM 11.2N 89.1W 11.6N 90.0W 12.2N 91.0W 12.8N 92.3W
LBAR 11.2N 89.1W 11.6N 89.6W 12.8N 90.3W 13.9N 91.0W
SHIP 20KTS 26KTS 36KTS 45KTS
DSHP 20KTS 26KTS 36KTS 45KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
100528 0000 100529 0000 100530 0000 100531 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 14.4N 92.3W 15.2N 93.2W 15.9N 91.1W 17.8N 88.4W
BAMD 13.5N 93.7W 14.5N 95.6W 15.0N 96.4W 16.1N 96.8W
BAMM 13.4N 93.4W 14.4N 94.6W 15.7N 93.4W 17.2N 92.5W
LBAR 15.0N 91.1W 17.2N 88.4W 18.6N 81.5W 24.6N 70.3W
SHIP 55KTS 69KTS 59KTS 52KTS
DSHP 55KTS 69KTS 52KTS 30KTS

...INITIAL CONDITIONS...
LATCUR = 11.2N LONCUR = 89.1W DIRCUR = 290DEG SPDCUR = 3KT
LATM12 = 11.0N LONM12 = 88.6W DIRM12 = 289DEG SPDM12 = 3KT
LATM24 = 10.8N LONM24 = 88.0W
WNDCUR = 20KT RMAXWD = 20NM WNDM12 = 20KT
CENPRS = 1007MB OUTPRS = 1008MB OUTRAD = 160NM SDEPTH = D
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting HaboobsRsweet:
I think 90E is our first real shot for a named storm. Conditions will be prime. Is 90L finally RIP? I saw some blogging this morning briefly when some still felt it had a shot?
Yeah I think it's RIP. Good call on this one HaboobsRsweet.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting FIU2010:
a question for either 456 or levi, or for both of them. alright, gentlemen, what do those low pressure anomalies that I see over the southeast and the carib. during the months of july, aug. and sept mean for us? Above all, why do i see the lowest pressure readings over the state of florida, what does that mean for floridians during this year's hurricane season, above all, for the peak months? Thanks, guys.


Basically, the low MSLP anomalies (if you're referring to the map I think you're referring to) means that conditions will be very favorable for tropical cyclogenesis, as well as intensification in those areas. This is because lower surrounding pressure is more conducive to the development and intensification of tropical cyclones.
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I think 90E is our first real shot for a named storm. Conditions will be prime. Is 90L finally RIP? I saw some blogging this morning briefly when some still felt it had a shot?
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Quoting pottery:

That clearly means that you are going to go into Depression.
LMAO!
Member Since: September 2, 2009 Posts: 130 Comments: 21194
i think that on friday, obama will truly intervene concerning the spill.
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Quoting MiamiHurricanes09:
What's everyone's opinion on 90E?


It becomes Agatha.
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1235. Buhdog
the link did not work try this if anyone can

there is something down there right now..from live feed..

http://www.wunderground.com/wximage/viewsingleimage.html?mode=singleimage&orig_handle=Buhdog&orig_n umber=&handle=Buhdog&number=14&album_id=8#slideanchor
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1234. pottery
Quoting FIU2010:
456, what do the low pressures over SF during the months of july, aug, and sept could mean for us? im referring to the anomolies, of course.

That clearly means that you are going to go into Depression.
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Did the Gulf stream separate lol? Take a look at this graph:

Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting StSimonsIslandGAGuy:
But sirs! It's moving west. IT'S MOVING WEST!!!!!


Westcaster!!
Member Since: March 10, 2010 Posts: 1 Comments: 7814
Latest Windsat on 90L


Member Since: September 23, 2005 Posts: 14 Comments: 11210
Quoting StSimonsIslandGAGuy:
Well on a creepy yet ultimately unimportant note, the center of the low moved north only 0.2 degrees between 18Z and 00Z, while moving west 0.9 degrees.

Gentlemen and sirs, is that ominous or unimportant?
No, that just means it was moving WNW, lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting winter123:
90L's last gasp? convection stopped firing, too much shear.
I think so too. Get ready for the 12,000 RIP's coming. lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1225. pottery
Quoting AussieStorm:

I'm going to grab my hot pack from the microwave, strap it to my neck and lay in bed. back in a few hours.

Top Priority for Immediate Broadcast
NSW SEVERE WEATHER WARNING
Flash Flooding

For people in Illawarra, Sydney Metropolitan and eastern Hunter districts.
Issued at 11:00 am on Wednesday 26 May 2010

Synoptic Situation: 9:00 am EST Wednesday
A low pressure system off Sydney coast is bringing local heavy rain to Illawarra and Sydney Metropolitan. As the low moves north-northeast heavy rain is expected to extend to eastern
parts of Hunter districts and ease in Illawarra and Sydney Metropolitan.

Rain, heavy at times may cause local flash flooding.

Severe Weather Warning for South Coast and eastern parts of Southern Tablelands has been cancelled.
Emergency services advise do not enter flood water. Stay well clear of creeks, storm drains and causeways.

Seriously. I would ice it instead of heat.
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Member Since: June 9, 2007 Posts: 4 Comments: 15920
90L's last gasp? convection stopped firing, too much shear.
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What's everyone's opinion on 90E?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Hurricanes101:


90L looks the most tropical and yet NHC says its chances are diminishing

Something doesn't seem right

Maybe they just don't want to name it, Being more stricter in naming systems.
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Quoting nrtiwlnvragn:
Ships still indictes possible rapid intensification with 90E.


Prob of RI for 25 kt RI threshold= 49% is 4.3 times the sample mean(11.5%)
Prob of RI for 30 kt RI threshold= 32% is 4.2 times the sample mean( 7.7%)
Prob of RI for 35 kt RI threshold= 25% is 4.8 times the sample mean( 5.2%)



Not surprising considering how favorable conditions are.
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Quoting pottery:

Close Call. Take care, Aussie. Sounds dread!

I'm going to grab my hot pack from the microwave, strap it to my neck and lay in bed. back in a few hours.

Top Priority for Immediate Broadcast
NSW SEVERE WEATHER WARNING
Flash Flooding

For people in Illawarra, Sydney Metropolitan and eastern Hunter districts.
Issued at 11:00 am on Wednesday 26 May 2010

Synoptic Situation: 9:00 am EST Wednesday
A low pressure system off Sydney coast is bringing local heavy rain to Illawarra and Sydney Metropolitan. As the low moves north-northeast heavy rain is expected to extend to eastern
parts of Hunter districts and ease in Illawarra and Sydney Metropolitan.

Rain, heavy at times may cause local flash flooding.

Severe Weather Warning for South Coast and eastern parts of Southern Tablelands has been cancelled.
Emergency services advise do not enter flood water. Stay well clear of creeks, storm drains and causeways.
Member Since: Posts: Comments:

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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.