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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How reliable are these intensity models? Does anyone really believe she could become a cat one Saturday near fl? Or a cat four for that matter in a few days?
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Should start to feel the trough soon with this organization.
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Quoting Seflhurricane:
have they found west winds my info is coming in really slow


Yes... there's some WSW to SW WNDs being reported.
Member Since: August 14, 2008 Posts: 4 Comments: 5038
Just found the center it seems, probably have a vortex message soon. Also much stronger west winds than they have found in the past. Is it possible Emily is IMPROVING her organization now?
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Quoting Seflhurricane:
have they found west winds my info is coming in really slow
Yup the LLC is as defined as ever.
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414. 7544
with this new info

shear going down

1003mb

lots of new conv over the llc again

still moving west might be in the reorganizing phase

seems it might not hit the high mountains and get knocked down

you think we might get a pseacial update before 5pm after the hh sends in the info

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1003.2 mb
(~ 29.62 inHg)
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Quoting pottery:

Yeah!
It's like a Court of Law in here sometimes.
With people making interpretations to suit their anxst!
Ridiculous at times.


That's angst! LOL How you doing, pott?
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Quoting Seflhurricane:
have they found west winds my info is coming in really slow



From 260° at 8 knots
(From the W at ~ 9.2 mph)
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dropping pressure....wrapping convection.

Still moving west......Hmmm.
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NOGAPS 12z

Link
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Quoting reedzone:


Hey Jeff, I figured you would like this...



Thats pretty good reedzone athough i dont see it making such a sharp turn N but i think your close if it makes a turn N tonight
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Marco of 1996 was a mini Ginger: Link

Not too many more abstract than this track, though:



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Emily may avoid the most rugged terrain if she continues moving west and threads the needle between cuba and haiti...
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403. unf97
Convection really beginning to fire around the LLC. It looks remarkably improved since late this morning. Shear may be letting up a bit in that area now and in fact, Emily may be trying to start to really organize right now. Time will tell.
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Quoting FLdewey:


No apology needed. Any reasonable person knew what you meant. ;-)


That's why the blog was full of confusion.
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Quoting MiamiHurricanes09:
There we go:

000
URNT15 KNHC 031830
AF306 0805A EMILY HDOB 13 20110803
182030 1647N 07025W 8433 01531 0042 +204 +103 092002 005 023 000 00
182100 1646N 07024W 8437 01526 0032 +218 +103 256007 009 024 000 00
182130 1644N 07023W 8440 01525 0039 +209 +104 245009 009 024 000 00
182200 1643N 07022W 8436 01528 0037 +213 +104 260008 008 025 000 00
182230 1641N 07021W 8436 01532 0039 +211 +102 243010 011 026 000 03
182300 1640N 07020W 8436 01530 0038 +213 +103 240015 015 028 000 00
182330 1639N 07019W 8437 01533 0040 +209 +104 248014 015 028 000 00
182400 1638N 07017W 8438 01531 0046 +203 +104 251015 016 029 000 00
182430 1636N 07016W 8438 01532 0046 +204 +104 235016 017 028 000 00
182500 1635N 07015W 8433 01537 0049 +200 +104 227017 018 028 000 00
182530 1634N 07014W 8435 01536 0051 +199 +104 231020 021 027 000 00
182600 1633N 07012W 8437 01533 0052 +197 +104 231021 022 027 000 00
182630 1632N 07011W 8436 01536 0055 +195 +104 228022 023 027 000 00
182700 1632N 07011W 8436 01536 0055 +194 +104 227022 023 027 000 03
182730 1630N 07009W 8437 01534 0056 +193 +104 222022 022 027 000 00
182800 1628N 07007W 8436 01536 0060 +187 +103 222021 022 027 000 00
182830 1627N 07006W 8436 01537 0064 +182 +102 219021 021 026 000 00
182900 1626N 07005W 8438 01535 0063 +185 +102 215020 020 027 000 00
182930 1625N 07004W 8433 01541 0064 +185 +100 213021 021 027 000 03
183000 1624N 07003W 8436 01540 0064 +186 +100 212021 021 030 000 00
$$
;
have they found west winds my info is coming in really slow
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There we go:

000
URNT15 KNHC 031830
AF306 0805A EMILY HDOB 13 20110803
182030 1647N 07025W 8433 01531 0042 +204 +103 092002 005 023 000 00
182100 1646N 07024W 8437 01526 0032 +218 +103 256007 009 024 000 00
182130 1644N 07023W 8440 01525 0039 +209 +104 245009 009 024 000 00
182200 1643N 07022W 8436 01528 0037 +213 +104 260008 008 025 000 00
182230 1641N 07021W 8436 01532 0039 +211 +102 243010 011 026 000 03
182300 1640N 07020W 8436 01530 0038 +213 +103 240015 015 028 000 00
182330 1639N 07019W 8437 01533 0040 +209 +104 248014 015 028 000 00
182400 1638N 07017W 8438 01531 0046 +203 +104 251015 016 029 000 00
182430 1636N 07016W 8438 01532 0046 +204 +104 235016 017 028 000 00
182500 1635N 07015W 8433 01537 0049 +200 +104 227017 018 028 000 00
182530 1634N 07014W 8435 01536 0051 +199 +104 231020 021 027 000 00
182600 1633N 07012W 8437 01533 0052 +197 +104 231021 022 027 000 00
182630 1632N 07011W 8436 01536 0055 +195 +104 228022 023 027 000 00
182700 1632N 07011W 8436 01536 0055 +194 +104 227022 023 027 000 03
182730 1630N 07009W 8437 01534 0056 +193 +104 222022 022 027 000 00
182800 1628N 07007W 8436 01536 0060 +187 +103 222021 022 027 000 00
182830 1627N 07006W 8436 01537 0064 +182 +102 219021 021 026 000 00
182900 1626N 07005W 8438 01535 0063 +185 +102 215020 020 027 000 00
182930 1625N 07004W 8433 01541 0064 +185 +100 213021 021 027 000 03
183000 1624N 07003W 8436 01540 0064 +186 +100 212021 021 030 000 00
$$
;
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Grothar:


I think that is 50.644 mph. :) You must be specific here, PP or they'll get you.



I didn't do so well in Algebra Gro, I just can't do it.
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Quoting ProgressivePulse:



It's been consistent past few runs in both track and showing a formidable hurricane just off the FL coast.


Definitely... GFDL has been jumping too much on the other hand. Will still be interesting to see how it looks on the 12Z run.
Member Since: August 14, 2008 Posts: 4 Comments: 5038
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Quoting DestinJeff:


That clearly spells DOOM for Florida.
Member Since: July 6, 2010 Posts: 113 Comments: 32877
Well, this Sea Surface Temperature map is back, but...looks a little screwy.

Member Since: July 6, 2010 Posts: 113 Comments: 32877
Quoting WxLogic:
12Z HWRF



It's been consistent past few runs in both track and showing a formidable hurricane just off the FL coast.
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Quoting FLdewey:


No apology needed. Any reasonable person knew what you meant.


Becoming an extinct species.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting JLPR2:
Emily is like the Energizer bunny. :\

Hello!


Also SAL is choking the wave/low in the CATL.

Hey JLPR, Check this out:

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Quoting BahaHurican:


The banks usually show up pretty well in the TCHP maps.


Member Since: July 6, 2010 Posts: 113 Comments: 32877
Quoting ProgressivePulse:
44 knots
(~ 50.6 mph)


I think that is 50.644 mph. :) You must be specific here, PP or they'll get you.
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I wonder, will the NHC have Emily moving Eastward soon in the cone, just to make sure she doesn't blow the forecasted movement along that track?? For three days we have been hearing how it will start to move NW. For three days the cone has slightly shifted west. It is now a near vertical movement to the North, which is likely not happening. At what point do they abandon that track and plot a realistic one?
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Once Em makes her turn, does that do anything to the atmosphere for following AOI's? CC,TX here and i know some of you would consider this wish casting but we need something SMALL to come through here and help us out. Don just did not do the trick!
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whats the site you can go to to view those vortex messages that miami09 just posted??
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The banks usually show up pretty well in the TCHP maps.
Member Since: October 25, 2005 Posts: 19 Comments: 22736
12Z HWRF
Member Since: August 14, 2008 Posts: 4 Comments: 5038
Quoting niederwaldboy:
Does any of this really matter????


Does anything really ever matter?
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Quoting MiamiHurricanes09:
They didn't find west winds though. They're looking around in the circulation.
The wind shift they found matched well with where they are in the circulation. they aren't on the south side yet.
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Quoting JLPR2:
Emily is like the Energizer bunny. :\

Hello!


Also SAL is choking the wave/low in the CATL.


That wave does not look friendly one bit.

--

Emily:

Member Since: July 6, 2010 Posts: 113 Comments: 32877
Quoting cloudburst2011:


emily will never enter the atlantic if she keeps moving west...those highs are getting closer together as the trof moves on out...emilys window is running out of time for that turn over haiti..


The highs may be building back in somewhat, but it still leaves a weakness in between the two domes. If the highs would consolidate into one massive high over the eastern seaboard, then yes, westward it will go for quite a while farther, until it gets drawn northward into the GOMEX. With as stout of a ridge over the Plains, it is unlikely that the two would be able to consolidate.
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They didn't find west winds though. They're looking around in the circulation.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting angelafritz:


This is true. I should have been more clear about that, so I modified my statement. Apologies.


You were clear about that, I'm pretty sure he/she was just trying to stir the blog.
Member Since: July 6, 2010 Posts: 113 Comments: 32877
370. wpb
Quoting SouthDadeFish:
Errmm not an impressive wind shift at all.
correct
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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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