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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370. wpb
Quoting SouthDadeFish:
Errmm not an impressive wind shift at all.
correct
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Quoting angelafritz:


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

Yeah!
It's like a Court of Law in here sometimes.
With people making interpretations to suit their anxst!
Ridiculous at times.
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368. JLPR2
Emily is like the Energizer bunny. :\

Hello!


Also SAL is choking the wave/low in the CATL.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
.
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Does any of this really matter????
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Quoting EYEStoSEA:


Well, hey there, Grothar....I'm in and out lately....always something going on here in my "neck of the woods" how's things in your "neck of the....beach" ?


I might be coming back to FL tomorrow. Hope I make it back if anything happens. Doesn't look like much yet. Hope you are doing well.
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1003.7 mb
(~ 29.64 inHg)

LOWEST PRESSURE SO FAR...
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Looks like more convection wrapping around. North, East and now starting on the south.
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Quoting pottery:

Priorities!
Get them Right.

Jeff will be unable to help you if you get them wrong, you know.

I believe that we will see a continued west motion for 4-6 hours.
By that time, a NW to N is on the cards IF CONDITIONS REMAIN THE SAME.
If your wrong i can blame you? COOL!!!
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Quoting MiamiHurricanes09:
Not bad; 1003.7mb.

181330 1648N 07020W 8440 01525 0037 +209 +101 124006 007 024 000 00
like you and others have said looks are deceiving She is starting to reorganize
Member Since: July 14, 2009 Posts: 0 Comments: 3026
Errmm not an impressive wind shift at all.

Edit: I just noticed they flew in a circle, scratch my statement.
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Quoting ecflweatherfan:
I definitely would not say that a period of RI is completely out of the question once Emily enters the Atlantic, between Cuba/Haiti and the Bahamas... waters there are in the upper 80s and are very deep, then there is the Gulf Stream, also mid to upper 80s and deep. So long as the other elements are also in place... low vertical wind shear and lack of dry air intrusion.
Well, all that water between Cuba and the Bahamas isn't deep. The great Bahama Bank on the W and S side of Andros is shallow enough in places for you to walk with water at waist/chest height. But along the Cuban and Hispaniolan coasts, along with the east side of Andros, yeah, there's plenty of deep water...
Member Since: October 25, 2005 Posts: 19 Comments: 22561
36. stormpetrol 5:16 PM GMT on August 03, 2011 +0

1757. stormpetrol 5:10 PM GMT on August 03, 2011 +0
I know some might laugh and thats ok , but it wouldn't surprise me if HHs find Emily a bit stronger!

Btw, I see the HHs flying over the south coast of PR/land
Action: Quote | Modify Comment

Remember this post! Look like I "might" be right!
Member Since: April 29, 2007 Posts: 0 Comments: 7980
Quoting angelafritz:


This is true. I should have been more clear about that, so I modified my statement. Apologies.
angela looks like Emily is hanging on and convection is wraping around the NE and East side your thoughts ???
Member Since: July 14, 2009 Posts: 0 Comments: 3026
Quoting bayoubrotha:
18:13:30Z 16.800N 70.333W 844.0 mb
(~ 24.92 inHg) 1,525 meters
(~ 5,003 feet) 1003.7 mb
(~ 29.64 inHg)

Nice. (for Emily, of course)
Member Since: July 7, 2010 Posts: 0 Comments: 5725
Not bad; 1003.7mb.

181330 1648N 07020W 8440 01525 0037 +209 +101 124006 007 024 000 00
Member Since: September 2, 2009 Posts: 130 Comments: 21194
18:13:30Z 16.800N 70.333W 844.0 mb
(~ 24.92 inHg) 1,525 meters
(~ 5,003 feet) 1003.7 mb
(~ 29.64 inHg)
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Quoting msgambler:
Destin, we have a problem!!! My wife told me to take out the trash and your telling me not to. What a pickle I find myself in at the moment.......Takin' Potterys advise and staying out of trouble. I'll pick up the trash in the yard later.

Priorities!
Get them Right.

Jeff will be unable to help you if you get them wrong, you know.

I believe that we will see a continued west motion for 4-6 hours.
By that time, a NW to N is on the cards IF CONDITIONS REMAIN THE SAME.
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349. angelafritz (Admin)
Quoting floodzonenc:
She was not expressing a personal desire to see the storm intensify and kill a bunch of people.... she obviously meant bad news for the storm.


This is true. I should have been more clear about that, so I modified my statement. Apologies.
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I hope the winds dont knock over any of my shiny aluminum cans that would constitute abuse of the highest level..
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346. DVG
Quoting reedzone, I figured you would like this...

I think you have the track right. The storm has continued west because it's been weak. I agree with those who see it currently regaining strength. The shear does seem to have lessened. I think it will need a few hours to reach a strength for the turn north. My guess is it turns at 72 west. Then we watch how the rest plays. What will set the blog on fire after 20n is how strong and when does it arc east. For all the confusion, the mist around this system is starting to become a little more clear.
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florida..yall looking at 40% chance of tropical force winds

Member Since: August 19, 2006 Posts: 13 Comments: 15990
Quoting MiamiHurricanes09:
They haven't reached the circulation yet.
looking at the winds thus far recon, the nhc can keep Emily as a 50 Mph TS
Member Since: July 14, 2009 Posts: 0 Comments: 3026
Quoting ecflweatherfan:
I definitely would not say that a period of RI is completely out of the question once Emily enters the Atlantic, between Cuba/Haiti and the Bahamas... waters there are in the upper 80s and are very deep, then there is the Gulf Stream, also mid to upper 80s and deep. So long as the other elements are also in place... low vertical wind shear and lack of dry air intrusion.


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..
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Quoting MiamiHurricanes09:
The NHC has Emily moving northwest immediatly. Do you really think that's plausible considering it's moving around 272˚ right now?



Nope.
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Quoting TropicalAnalystwx13:


Where did you download that from? Not GREarth, but the wind product thing (lol)?


That's just the 10-M wind analysis.

Changed the arrows to barbs.
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Quoting Seflhurricane:
do we have a vortex message yet ???
They haven't reached the circulation yet.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
339. myway
Quoting islander101010:
you got to be kidding


Nope.....we need the business.
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do we have a vortex message yet ???
Member Since: July 14, 2009 Posts: 0 Comments: 3026
Quoting Stormchaser2007:


Yeah.

Had it since October.


Where did you download that from? Not GREarth, but the wind product thing (lol)?
Member Since: July 6, 2010 Posts: 113 Comments: 32499
Hello everyone. Looking at latest satellite in motion pictures, looks like Emily may miss Dominican Republic, an head further west, also see some organization occurring.Hope Emily is no sister of Cleo 196o's fame.
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I definitely would not say that a period of RI is completely out of the question once Emily enters the Atlantic, between Cuba/Haiti and the Bahamas... waters there are in the upper 80s and are very deep, then there is the Gulf Stream, also mid to upper 80s and deep. So long as the other elements are also in place... low vertical wind shear and lack of dry air intrusion.
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Quoting Grothar:


You just haven't been around long enough. How would the blog have dealt with this one.

you are correct. I haven't been alive that long and I have just started to track storms. I wanted to learn more about hurricanes, so I came on here. TS Emily was going to be my first lesson, but it turn out I should have waited until the next storm, lol.
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Time: 17:58:00Z
Coordinates: 17.4N 69.7W
Acft. Static Air Press: 842.9 mb (~ 24.89 inHg)
Acft. Geopotential Hgt: 1,563 meters (~ 5,128 feet)
Extrap. Sfc. Press: 1010.9 mb (~ 29.85 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 118° at 35 knots (From the ESE at ~ 40.2 mph)
Air Temp: 14.5°C (~ 58.1°F)
Dew Pt: 7.4°C (~ 45.3°F)
Peak (10s) Flt. Lvl. Wind: 37 knots (~ 42.5 mph)
SFMR Peak (10s) Sfc. Wind: 42 knots (~ 48.3 mph)
SFMR Rain Rate: 9 mm/hr (~ 0.35 in/hr)
(*) Denotes suspect data
Member Since: April 29, 2007 Posts: 0 Comments: 7980
Quoting myway:


Come on down. The weather is beautiful. Bright sun, calm seas and the wildlife on the beaches is great. Even if Emily does pay a visit it will be really nice the day before and the day after.
you got to be kidding
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Destin, we have a problem!!! My wife told me to take out the trash and your telling me not to. What a pickle I find myself in at the moment.......Takin' Potterys advise and staying out of trouble. I'll pick up the trash in the yard later.
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Quoting TropicalAnalystwx13:


Is that GREarth?


Yeah.

Had it since October.
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Quoting FLWeatherFreak91:




This hypothesis may be out on a limb, but does anyone reckon the geography and curvature of Hispaniola may be helping to strengthen and define Emily's vortex by enhancing lift?


Not an absurd theory, the orographic lifting effect can certainly induce rain/convection, I am unsure however if it would have an effect on the circulation itself, but if nothing else it can provide convection.
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Quoting Stormchaser2007:
Convection now covering up the center

FULL IMAGE



Is that GREarth?
Member Since: July 6, 2010 Posts: 113 Comments: 32499
are the models predicting a stronger storm closer to S.fl im going on vaca there on friday
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Quoting Grothar:


Thanks, Jup, I do my best.


Well, hey there, Grothar....I'm in and out lately....always something going on here in my "neck of the woods" how's things in your "neck of the....beach" ?
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325. myway
Quoting ChrisDcat5Storm:
WAIT is this true modles are predicting a strong storm closer to FL say it aint so im going on vacation there


Come on down. The weather is beautiful. Bright sun, calm seas and the wildlife on the beaches is great. Even if Emily does pay a visit it will be really nice the day before and the day after.
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Quoting Bluestorm5:
Yea, I've never seen a tropical system this weird before.


You just haven't been around long enough. How would the blog have dealt with this one.

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EMILY has strengthened. Down 2mb's actually.
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Quoting ChrisDcat5Storm:
WAIT is this true modles are predicting a strong storm closer to FL say it aint so im going on vacation there
couple of models are now saying Category 1 offshore of Florida, and one of the model is saying Category 3 for Florida rising to near Category 4 offshore of Carolinas. Wonderful news for people living on beaches... not.
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321. 7544
there she goes again ms emily she heading for the passage and may not get knocked out for the count according to the above map is shear might be letting up little today hmmm
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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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