High wind shear disrupts Emily as it approaches Hispaniola

By: Dr. Jeff Masters , 5:06 PM GMT on August 03, 2011

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In defiance to its forecast, Tropical Storm Emily continues to move due west this morning, and we wonder just how far west it will get before turning toward Hispaniola. Recent Hurricane Hunter missions have shown that Emily is still very poorly organized, and although the center of circulation is plainly obvious on satellite imagery, it's only because it is so displaced from the thunderstorm activity. Wind shear around the storm is just high enough, around 20 knots out of the west, to push the upper levels of circulation and thunderstorm activity to the east, exposing the surface low. In order for tropical cyclones to intensify (or, continue to exist at all), they need to be vertically stacked and standing straight up in the atmosphere. Right now, Emily is tilting to the east. This is bad news for the organization of the storm, and something that Emily will have to work hard at recovering from. In addition to the wind shear, dry air continues to wrap around the north and west of the storm. This isn't as critical as unfavorable wind shear, but it's not helping to create new thunderstorm activity. The strongest winds of 50 mph were found to the north and east of the center this morning, and Emily is not expected to intensify before making landfall in Hispaniola, which is forecast for tonight. The HWRF is forecasting the strongest precipitation to fall on the northeast side of the storm as is passes over Hispaniola. This is relatively good news for Haiti, but the country could still receive up to 5 inches of rain, and since the models have been trending the track west over the past couple of runs, it's something to watch closely. No matter the scenario, Emily is expected to produce heavy rains, flash flooding, and mudslides in Haiti and the Dominican Republic, which are all to common on the mountainous island.


Figure 1. Forecast precipitation accumulation from the HWRF high resolution model's 6Z (2am EDT) run. The color contour scale is in inches. The coastlines are a thin, red line. The Dominican Republic is expected to get the most rain out of Emily. You can view the HWRF model runs on Wundermap.

Forecast for Tropical Storm Emily
The future of Emily remains uncertain, and even the National Hurricane Center is using the "if" word when forecasting Emily's track after crossing Hispaniola. "If" it makes it north of Hispaniola. Over the past couple of runs, the models have been trending their forecast tracks back to the west, most likely because Emily has remained on a westward track longer than expected. This is expected—the longer Emily remains shallow and unorganized, the longer it will track west. It will need to build up taller in the atmosphere to be influenced by the steering winds that can push it north. Given its westward track, today's models are likely closer to reality than what we've seen in the past couple of days. This morning, the CMC, UKMET, and HWRF models send Emily on a northwest track to Florida. This is a change from the past couple of days for the HWRF, but the CMC and UKMET have consistently been the western boundary of model consensus. THE GFDL has also taken a huge swing to the west, and now suggests it will come very close to a southeast Florida landfall. The ECMWF and GFS continue to forecast that Emily will take a harder turn north through the Bahamas, not reaching the Florida coast.


Figure 2. Satellite image of Tropical Storm Emily at 11:15am EDT. The surface circulation is visible to the west of the strongest thunderstorm activity.

Consensus of the models falls between the HWRF/GFDL solution and the ECMWF/GFS solution, and the National Hurricane Center continues to use the consensus for the official track forecast, which calls for Emily to take a turn to the northwest and make landfall in Hispaniola this afternoon, after which continuing northwest until Saturday morning when it's between the island of Grand Bahama and West Palm Beach, Florida. At this point, they expect the storm to jog north and then northeast.

Emily's intensity forecast continues highly dependent on the track it takes. Assuming it can survive the wrath of Hispaniola, Emily will enter slightly more favorable environmental conditions to the north of the islands. This is what the Hurricane Center is forecasting, although they remain cautious. There is a very good chance that, if Emily does turn northwest today, it will not be able to reorganize after crossing Hispaniola. If it does maintain organization, Emily could reach hurricane strength as it moves northeast out to the open Atlantic. The other scenario at this point is that the storm keeps moving west, which will be detrimental to its orgnization. The models that track Emily into the far eastern Gulf of Mexico don't suggest any reintensification—the CMC fizzles the system below tropical storm strength quickly, probably because of the long track over Cuba it would have to take. In any case, Emily remains a threat most certainly to Hispaniola, and potentially to Florida.

I'm planning a quick update later this afternoon/evening for an update on new model runs, and potential Hispaniola landfall.

Angela

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Quoting Grothar:


I've been posting images since last night and no one has commented. They just don't care. :)

Quite the impressive image Gro.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
more than likely the NHC will issue tropical storm warnings for the central bahamas and a tropical storm watch for the northwestern bahamas . IMO
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Quoting CycloneUK:


No offense intended, but do you have a learning disorder?

I mean sure weather and storms are interesting and all but you my friend are obsessive to whole new levels.
Meaning to be rude, do you really have to ask that question in an open blog. Respect other's feelings.
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Quoting Stormchaser2007:
G-IV has taken off from Nassau.
Wow... didn't realize they were staging from here... could have gone down 2 the airport to see the plane.

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Ehhhh...

Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting Drakoen:
I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.




I've been posting images since last night and no one has commented. They just don't care. :)

Member Since: July 17, 2009 Posts: 63 Comments: 23727
Quoting Drakoen:
I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.




Quite a wave indeed.

Not sure if that's the wave the JMA model develops.
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Quoting ecflweatherfan:
As for Watches and Warnings... anyone think any US mainland watches will be posted at 5pm???
dont think so maybe tomorrow if she reorganizes well and conti ues to be a threat
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Emily LLC still firing off thunderstorms and they still getting sheared off the center,but alive she is and trying hard. looks like she will mis Hispaniola all together unless she hooks hard right,something she has shown no tendency to do.

I watched Levi's Tidbits and feel that he pretty much has it right. Looks like Florida for landfall to me, and I'm picking the west coast town of Bonita Springs as the bullseye so to speak. It may parallel to the southwest florida coast for a bit and hit land with a heading of NE Or ENE, As a Tropical Storm Or Cat 1/Minimal Hurricane.

JMHO
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Quoting ncstorm:


The GFS and NAM solutions on here make it look like they are redeveloping the center of circulation further to the south. Levi was pointing out that recon is still finding lowering pressure that way.

Still think we are going to see a new center once that first starts to hit the mountains - even if in the windward passage. Don't discount them - they are tall!
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Quoting weatherman12345:
JK LOL


you realize you made me go back several pages to see if i missed it on a F5 ya know :P
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I think on the next pass, they'll find the center just a tad southwest of the previous fix.
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706. emguy
Quoting ecflweatherfan:
As for Watches and Warnings... anyone think any US mainland watches will be posted at 5pm???


Higly doubt that would happen due to the timeframe. However, that may be a possibility in about 24 hours.
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cant help notice that T-storms r building near the center
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Quoting tiggeriffic:


reported for what? coc=center of convection...tucking it under is pulling it together to get stacked...
Stacked is good.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
Watch this loop of the NHC forecast tracks. They're obviously overestimating the severity of the northern turn:

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Quoting TropicalAnalystwx13:


Please...Just:



1000+++
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Quoting tiggeriffic:


personally wish there was such a thing as a cyber rubberband shooter to ward off the trolls and pop em between the eyes at the same time...

Oh my gosh tigger....I needed a good laugh....so very true....DITTO :)
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Emily has really kept status quo and I see no real chance of intensification over the next 24 hours do to land interaction and current state she is in right now.
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Quoting Drakoen:
I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.


just saw that very impressive Next TD ??
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Quoting Drakoen:
I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.




Drak: I think we are out of practice having more than one to think about at a time. Few years of relative loners does that to you.

Pulling on what I have learned though, is that systems following close behind another system tend to go in the same general direction.
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This one moved a lot over the past few days.

Member Since: July 17, 2009 Posts: 63 Comments: 23727
Quoting Drakoen:
I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.




Very nice. I wonder if there is any future for that one.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting Drakoen:
I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.



Very impressive.
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Quoting BoroDad17:
Tstorm over the COC is popping up again. She really is trying hard to get some clothes back on.


Maybe if she didnt have such a broad middle, it would be easier for her to clothe herself?!?
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Quoting emguy:
This whole setup has a similar feel to Tropical Storm Ernesto in 2006 and Fay in 2008. Will be interesting if this passes between Jamaica and Cuba.


Could follow a similar track or maybe a little farther east.
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Quoting tiggeriffic:


reported for what? coc=center of convection...tucking it under is pulling it together to get stacked...
He/She was joking because the way my comment looked.
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Quoting Drakoen:
The HWRF, GFDL, and ECMWF 12z runs look to have a good track with a system that crosses over the narrow strip of Haiti and through the Windward Passage on a track in the general direction of South Florida.


Thanks, just wanted I wanted to hear. Anyway you can revise them?
Member Since: July 17, 2009 Posts: 63 Comments: 23727
Thank you! :)

Quoting 7544:


Link
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Quoting kmanislander:


She's a fighter for sure but most systems that battle 20 knots of shear persist like this. 20 knots is just enough to expose the center but not quite enough to destroy a tenacious circulation. The shear eases off near the Western tip of the Tiburon peninsula so if the track continues to the West and she can hold on it could get very interesting to the South of Cuba.
Thanks for clarifying that. I thought you were expecting her demise.
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Quoting carolinabelle:
Could someone post a good reliable link to the HWRF model? The one I have keeps breaking on me... thanks so much!

HWRF
NOAA HFIP Experimental HWRF
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Quoting patrikdude2:
Where do you get the old NHC cone path from???
Advisory archive.
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As for Watches and Warnings... anyone think any US mainland watches will be posted at 5pm???
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Tstorm over the COC is popping up again. She really is trying hard to get some clothes back on.
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678. 7544
Quoting carolinabelle:
Could someone post a good reliable link to the HWRF model? The one I have keeps breaking on me... thanks so much!


Link
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Thanks Levi, Kman -- so Emily is a storm, but still attached to a part of the low that it moved across with. That's an interesting set up. It doesn't want to let go of its roots!
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Quoting MiamiHurricanes09:
First track in contrast with the 2p.m position. Pretty good with timing.



Still hugging the left edge of the cone.
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Quoting PrivateIdaho:


re ported!
LOL. I didn't realize how it looked until you re ported me.
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I know everyone is fixed on Emily but there is an very impressive wave just off the coast of Africa.


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Could someone post a good reliable link to the HWRF model? The one I have keeps breaking on me... thanks so much!
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Quoting MiamiHurricanes09:
First track in contrast with the 2p.m position. Pretty good with timing.

Where do you get the old NHC cone path from???
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About JeffMasters

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