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 lucreto:


Systems do tend to thread the needle more often than statistically expected, it could be a masters thesis for someone I suppose.


Can you site some? Off the top of my head, I don't remember any.
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Quoting Buhdog:


Charley did it....even blinked at ya few times as it passed under cuba.
How about Ivan who turned slightly on approach to Jamaica, missed the island, then turned back to continue its straight line across the Caribbean?
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Quoting winter123:


Both of you are wishcasting. The odds of it threading the needle like that just to stay over water are minimal. Cyclones do not have brains. Due to the current west motion I think it's more likely it will pass over eastern cuba, which is also very mountainous. But if it really cannot get it's act together, stays an exposed low like this, I think it could miss the trough and continue WNW even into the gulf, such as a couple models are suggesting.


I agree that those odds are really pretty poor of staying completely over water. However, I do see the current center running into the terrain and a new center forming further south. Mapped out on a chart, it would look like it continued westward and even made a little jog.
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Quoting MiamiHurricanes09:
Miami looks like emily is trying to come back nice convection firing hopefully it cane expand
Member Since: July 14, 2009 Posts: 0 Comments: 2990
storms much closer to center now. we will see....
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Member Since: September 2, 2009 Posts: 130 Comments: 21032
Emily putting her clothes back on:
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Quoting FLWeatherFreak91:
Absolutely. Looking at a record of all Caribbean storms, the majority of them somehow parallel the island chain, avoiding much interaction.


Charley did it....even blinked at ya few times as it passed under cuba.
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Quoting weatherman566:
Southerly shear west of Emily will likely force the convection further north. Maybe she'll eventually feel the weakness and push NW by that point.
I can definitely see the southerly shear out ahead of Emily, but I can clearly see the low level clouds moving just north of west. The trof has yet to veer the winds around in the Caribbean.
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Quoting FLWeatherFreak91:
Yes, out to sea would be NE lol


Oops! Yeah, a little brain dead today.
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Quoting Grothar:
GFDL

check out GFDL strength on this track.
Link
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Quoting winter123:


Both of you are wishcasting. The odds of it threading the needle like that just to stay over water are minimal. Cyclones do not have brains. Due to the current west motion I think it's more likely it will pass over eastern cuba, which is also very mountainous. But if it really cannot get it's act together, stays an exposed low like this, I think it could miss the trough and continue WNW even into the gulf, such as a couple models are suggesting.

Wishcasting? How is it wishcasting when even the National Hurricane Center has it taking a similar path? I guess the experts are wishcasting too, huh?



P451, borrowing your image for a minute.


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Looks like convection is catching up
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Personally, I think that IF Emily goes across the southwestern peninsula of Haiti into the Windward Passage, it will mean that Emily will spend minimal time over land, e.g. less weakening. When it emerges back into the Windward Passage, it will begin to pick up some strength. As a stronger system then, the more likely it would be to miss the CONUS.
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Southerly shear west of Emily will likely force the convection further north. Maybe she'll eventually feel the weakness and push NW by that point.
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Quoting Buhdog:


I have trekked many systems that sure acted like it had a brain...threading the needle at every chance it has, strengthening phase while hitting land. Sometimes they even have one good eye to see with.
Absolutely. Looking at a record of all Caribbean storms, the majority of them somehow parallel the island chain, avoiding much interaction.
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Quoting FLWeatherFreak91:
Yep. Eastern Cuba isn't too friendly looking.


The mountains in Eastern Cuba are the Oriente Mountains... yes they are daunting to a swamped LLC...
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Tropical Storm EMILY Storm Archive
...EMILY STILL MOVING WESTWARD...APPEARS TO BE LESS ORGANIZED.....
2:00 PM EDT Wed Aug 3
Location: 16.8°N 70.3°W
Max sustained: 50 mph
Moving: W at 14 mph
Min pressure: 1006 mb
Member Since: Posts: Comments:
195. IKE
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 PM EDT...1800 UTC...THE CENTER OF TROPICAL STORM EMILY WAS
LOCATED NEAR LATITUDE 16.8 NORTH...LONGITUDE 70.3 WEST. EMILY IS
MOVING TOWARD THE WEST NEAR 14 MPH...22 KM/H. A TURN TO THE
NORTHWEST IS EXPECTED LATER TODAY. ON THE FORECAST TRACK...THE
CENTER OF EMILY WILL MOVE VERY NEAR OR OVER CABO BEATA IN THE
DOMINICAN REPUBLIC LATE TODAY...OVER HAITI TONIGHT...AND INTO THE
SOUTHEASTERN BAHAMAS AND TURKS AND CAICOS ISLANDS ON THURSDAY.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 50 MPH...85 KM/H...WITH HIGHER
GUSTS. A RECONNAISSANCE AIRCRAFT IS CURRENTLY APPROACHING EMILY AND
WILL GIVE A BETTER ESTIMATE OF THE INTENSITY. LITTLE CHANGE IN
STRENGTH IS FORECAST TODAY BEFORE THE CENTER REACHES THE WESTERN
PORTION OF HISPANIOLA...FOLLOWED BY WEAKENING AS THE CENTER MOVES
OVER THE HIGH TERRAIN.
SOME RE-STRENGTHENING IS POSSIBLE AFTER THE
CENTER MOVES AWAY FROM HISPANIOLA.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115 MILES...185 KM
TO THE NORTH AND EAST OF THE THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB...29.71 INCHES.
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WX logic i was refering to the 12z run I know it is current but will be old run soon was trying to say I guess is that one model run is not enough you have to look at model trends from run to run then make your statement. Was not really saying you are wrong or any thing just stating how I come to my opinion. Sorry for the bad wording.
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000
WTNT35 KNHC 031746
TCPAT5

BULLETIN
TROPICAL STORM EMILY INTERMEDIATE ADVISORY NUMBER 8A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052011
200 PM EDT WED AUG 03 2011

...EMILY STILL MOVING WESTWARD...APPEARS TO BE LESS ORGANIZED.....


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...16.8N 70.3W
ABOUT 120 MI...190 KM SSW OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES
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When all said and done, my guess is the 12Z CMC has the actual outcome nailed.
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I don't see the circulation coming ashore anywhere in Hispaniola. I think it will skirt by just south of the tiburon peninsula.
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GFDL

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Quoting winter123:


Both of you are wishcasting. The odds of it threading the needle like that just to stay over water are minimal. Cyclones do not have brains. Due to the current west motion I think it's more likely it will pass over eastern cuba, which is also very mountainous. But if it really cannot get it's act together, stays an exposed low like this, I think it could miss the trough and continue WNW even into the gulf, such as a couple models are suggesting.


I have trekked many systems that sure acted like it had a brain...threading the needle at every chance it has, strengthening phase while hitting land. Sometimes they even have one good eye to see with.
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Quoting winter123:


Both of you are wishcasting. The odds of it threading the needle like that just to stay over water are minimal. Cyclones do not have brains. Due to the current west motion I think it's more likely it will pass over eastern cuba, which is also very mountainous. But if it really cannot get it's act together, stays an exposed low like this, I think it could miss the trough and continue WNW even into the gulf, such as a couple models are suggesting.


They are not, they are well respected and reliable folks on this blog.
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You see good storms like Gustav (2008), Ernesto (2006), and Jeanne (2004) get ripped apart by going over Haiti.. However weak storms like Fay (2008)survive hard trips.. I got my eye on Emily, especially if she shoots the gap, not much weakening there, unless shear continues on but there are signs that shear is weakening, according to the CIMMS map, wind shear is lifting out.
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2 pm is out
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185. wpb
gfs 12z open wave through 36 hors
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Quoting NavarreMark:


Thanks Reed. I knew buying 6 cases of beer was the proper thing to do. We still don't know where Emily is going. Stay Safe.
But reading this blog, you'll be out by the time the storm reaches you. The stores will be out and you will have to drink water.
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Quoting PcolaDan:
thatthatthatthatthatthatthatthatthatthat

edit: good catch Gro and thanks Angela


anytime.
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Near naked swirl barreling west on vis sat loop. FL is going to get hit.... by a naked swirl.
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Looks like southerly shear just west of Emily
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179. unf97
Quoting cat5hurricane:
I don't see any breaking down of the western periphery of the LLC whatsoever. If anything, it consolidating as it is firing up and sucking more convection and heat in from the northern fringe of the surface circulation.


I agree. Convection has been re-firing from the NE of the LLC so far this afternoon. The LLC still appears to be still fairly well defined on visible satellite imagery.
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Quoting patrikdude2:
http://www.swellinfo.com/tropical/hw3.php?forecas t=plotsystemmodels&storms=®ion=NT&year=&a mp;eventnum= 5&hwvstormid=5&usemap=AUTO2&zoom=0& ;size=&config=tr opsys640x480,tropimap_all&pn=1&ptm=

GFDL model has it a Cat3 right off the Florida East coast. (LINK: Hover over the GFDL model path next to Florida.)
and 125 MPH winds offshore of North Carolina (where I live)? Wow... this is too extreme IMO.
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Quoting winter123:


Both of you are wishcasting. The odds of it threading the needle like that just to stay over water are minimal. Cyclones do not have brains. Due to the current west motion I think it's more likely it will pass over eastern cuba, which is also very mountainous. But if it really cannot get it's act together, stays an exposed low like this, I think it could miss the trough and continue WNW even into the gulf, such as a couple models are suggesting.
Yep. Eastern Cuba isn't too friendly looking.

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emily doesnt care what the models say,didnt the nogaps actually predict a simular path that she's taken over the last 48hrs,days ago?
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...EMILY STILL MOVING WESTWARD...APPEARS TO BE LESS ORGANIZED.....
2:00 PM EDT Wed Aug 3
Location: 16.8°N 70.3°W
Max sustained: 50 mph
Moving: W at 14 mph
Min pressure: 1006 mb
Member Since: Posts: Comments:
173. IKE
11:00 AM AST Wed Aug 3

Location: 16.7N 69.7W

Max sustained: 50 mph

Moving: W at 14 mph

Min pressure: 1006 mb
................................................. ...............

...EMILY STILL MOVING WESTWARD...APPEARS TO BE LESS ORGANIZED.....






2:00 PM EDT Wed Aug 3

Location: 16.8N 70.3W

Max sustained: 50 mph

Moving: W at 14 mph

Min pressure: 1006 mb
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172. 7544
cmc Link
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Quoting djboca:
Right now, Emily is tilting to the east. This is bad news, and something that Emily will have to work hard at recovering from.

Bad news? Are you seriously "championing" a storm that may cause death and destruction? Can you PLEASE keep your comments limited to facts and restrict your opinions to weather predictions while avoiding "scare tactics" (ie: worst summer, worst this, worst that) and "cheering" for storms?

This type of blogging by an intelligent and respected scientist is getting to be as bad as our national politicians' behavior.

Good Grief!!!!
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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.