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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And....more importantly, those are runs that completed at mid-day today....what Miami and others have been posting are quite a change, even if ALL of them are on top of each other again.

Quoting tropicalweather2011:


Member Since: Posts: Comments:
Quoting lovemamatus:
But if Emily finds the ultimate loop current, and the pressure drops to 866 mb, with winds of 210 gusting to 245.....WE ARE DOOOOOMED!!!!!!!!!!!
We could always nuke the LLC.
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Quoting TropicalAnalystwx13:
What's with all these beautiful Eastern Pacific storms so far this season?

Hurricane Adrian:



Hurricane Dora:



Hurricane Eugene:


Well you try telling mother nature to stop being beautiful! LOL
Member Since: July 7, 2010 Posts: 0 Comments: 5725
Time: 23:11:00Z
Coordinates: 17.0333N 70.1667W
Acft. Static Air Press: 842.9 mb (~ 24.89 inHg)
Acft. Geopotential Hgt: 1,557 meters (~ 5,108 feet)
Extrap. Sfc. Press: 1009.0 mb (~ 29.80 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 158° at 26 knots (From the SSE at ~ 29.9 mph)
Air Temp: 16.2°C (~ 61.2°F)
Dew Pt: 7.5°C (~ 45.5°F)
Peak (10s) Flt. Lvl. Wind: 31 knots (~ 35.6 mph)
SFMR Peak (10s) Sfc. Wind: 47 knots (~ 54.0 mph)
SFMR Rain Rate: 15 mm/hr (~ 0.59 in/hr)
(*) Denotes suspect data

Wonder if NHC will raise it 55-60mph at 8pm
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Quoting MiamiHurricanes09:
I would be looking towards the west based off of how the winds shifted in the location that they dropped the sonde.


If it is meandering I would look near 17.1 and 70.3,
just NE of the advisory center fix
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Quoting kmanislander:
17.100N 69.700W 842.4 mb
(~ 24.88 inHg) 1,568 meters
(~ 5,144 feet) 1010.1 mb
(~ 29.83 inHg)

Time to change course for the HH


Think they are heading back to base, scheduled mission complete.

They have another 1/2 hour to go per schedule
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1662. LBAR
Obvious swirl in Bay of Campeche...although very small may it bring rain to Texas!
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That isn't all of them, but point made....

Quoting tropicalweather2011:


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BRB
Member Since: October 25, 2005 Posts: 19 Comments: 22736
1659. zawxdsk
Quoting ncstorm:
954 mb..and this is why i was asking how wide is Emily..thats too close for comfort


Instead of 5-0-0 I think that would put us at 5-1-1. Haha, we'll see...
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1658. ncstorm
Quoting zawxdsk:


The NHC has maintained for most of the updates that they do expect hurricane status when the storm falls due east of Jacksonville, FL.

I don't think this is quite what they had in mind though...


no this is not what they were thinking.. I believe they had a 3% chance of a category 3..
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Quoting BahaHurican:
kman, did u see a 5th Vortfix circle?


Not yet.
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Quoting HurricaneHunterJoe:
depends which wishcaster you talk to......lol


Good one lmao!!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Quoting kmanislander:
Pressure much higher as they fly East. No lower readings there.
I would be looking towards the west based off of how the winds shifted in the location that they dropped the sonde.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
What's with all these beautiful Eastern Pacific storms so far this season?

Hurricane Adrian:



Hurricane Dora:



Hurricane Eugene:

Member Since: July 6, 2010 Posts: 113 Comments: 32874
Quoting zawxdsk:


The NHC has maintained for most of the updates that they do expect hurricane status when the storm falls due east of Jacksonville, FL.

I don't think this is quite what they had in mind though...


It's only one model, no reason to get to worried yet. If others start backing that up, then it will be something to be concerned about.
Member Since: Posts: Comments:
17.100N 69.700W 842.4 mb
(~ 24.88 inHg) 1,568 meters
(~ 5,144 feet) 1010.1 mb
(~ 29.83 inHg)

Time to change course for the HH
Member Since: Posts: Comments:
Quoting kmanislander:
The HH is now flying due East along the 17 degree lat line , perhaps looking to see if the 1003 mb reading is "circling around"
kman, did u see a 5th Vortfix circle?
Member Since: October 25, 2005 Posts: 19 Comments: 22736
The models are not providing any run to run consistency, as many of you have said. This is truly a wait and see kinda storm. More twists and turns than a good suspense novel. Yet, nothing to be suspenseful about, it is still just a 50 MPH TS (I know, try telling that to the people of Hispanola).
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I think they will be flying back in from the East to west to get another fix, even if not , the pattern clearly represents meandering or center relocation, no clear movement as of yet , just my opinion.
Member Since: April 29, 2007 Posts: 0 Comments: 8134
1647. zawxdsk
Quoting ncstorm:
959 mb..a category 3


The NHC has maintained for most of the updates that they do expect hurricane status when the storm falls due east of Jacksonville, FL.

I don't think this is quite what they had in mind though...
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Pressure much higher as they fly East. No lower readings there.
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Run complete; 126 hours.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting tiggeriffic:


i still have a funny feeling that the timing with the models is off and the high is gonna flatten out blocking Emily...she isn't strong enuf now to feel the trough and when she crosses over HP and Cuba, she may not be that much weaker but cant see a strengthen until she is completely over...by then...the gap will be closed...and im not talkin bout the one where you buy your jeans from either
Haha like the last part.
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Quoting Chucktown:


Not worried here, ain't gonna happen. Why do we continue to post worst case scenarios while we are tracking a naked swirl...just sayin.


It's called discussing all possibilities XD.

I've said from day one I think this will recurve east of the US (although I never called it a fish, as it is hitting the NE Caribbean islands). I just mentioned that SC/NC should watch it carefully (as should everybody, really), although they appear to be safe in that run.
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Quoting Chucktown:


Not worried here, ain't gonna happen. Why do we continue to post worst case scenarios while we are tracking a naked swirl...just sayin.


Probably not going to happen, but it's another possibility.
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Dropsondes from HH, only found 1003.8 at the lowest...
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Quoting Chucktown:


Not worried here, ain't gonna happen. Why do we continue to post worst case scenarios while we are tracking a naked swirl...just sayin.
Not a naked swirl.

And conditions are favorable for intensification once Emily gets into the southwestern Atlantic. Not saying that intensification like that will happen, but it's just another possibility that's on the table.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
I nearly spit out my drink I laughed so hard...Everyone is being pretty good-natured about it though...

Quoting HurricaneHunterJoe:
depends which wishcaster you talk to......lol
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1638. ncstorm
954 mb..and this is why i was asking how wide is Emily..thats too close for comfort
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1637. WxLogic
Quoting MiamiHurricanes09:
Damn.

Moving NE at 114 hours.



18Z GFDL could be same...
Member Since: August 14, 2008 Posts: 4 Comments: 5038
Quoting TropicalAnalystwx13:
I'll put a lot more stock in the HWRF now that it has received an upgrade.



I won't, as far as I can tell none of the models have been consistent or reliable with this storm so far.
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18Z HWRF has Emily recurving right along the Gulf Stream basically, so no wonder it keeps intensifying like that lol.
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Quoting TropicalAnalystwx13:
I'll put a lot more stock in the HWRF now that it has received an upgrade.



It gets upgraded almost every year, so to me... eh
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Time: 23:03:30Z
Coordinates: 17.0167N 70.5667W
Acft. Static Air Press: 842.6 mb (~ 24.88 inHg)
Acft. Geopotential Hgt: 1,538 meters (~ 5,046 feet)
Extrap. Sfc. Press: 1004.4 mb (~ 29.66 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 89° at 8 knots (From the E at ~ 9.2 mph)
Air Temp: 20.1°C (~ 68.2°F)
Dew Pt: 9.3°C (~ 48.7°F)
Peak (10s) Flt. Lvl. Wind: 9 knots (~ 10.3 mph)
SFMR Peak (10s) Sfc. Wind: 16 knots* (~ 18.4 mph*)
SFMR Rain Rate: 1 mm/hr* (~ 0.04 in/hr*)
(*) Denotes suspect data

Unless they do another pass, is this the new fix?!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Quoting tropicalweather2011:
Tropical Storm Emily going out to sea


Poser, I was saying this in late July.

J/K, hahaha.
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Quoting HurricaneSwirl:


964 mb. All you people in SC/NC better hope this recurves sharply, although you look safe in this run so far :P


Not worried here, ain't gonna happen. Why do we continue to post worst case scenarios while we are tracking a naked swirl...just sayin.
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Quoting ackee:
WHAT DIRECTION is EMILY MOVING NOW ?
depends which wishcaster you talk to......lol
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Quoting HurricaneSwirl:


964 mb. All you people in SC/NC better hope this recurves sharply, although you look safe in this run so far :P


i still have a funny feeling that the timing with the models is off and the high is gonna flatten out blocking Emily...she isn't strong enuf now to feel the trough and when she crosses over HP and Cuba, she may not be that much weaker but cant see a strengthen until she is completely over...by then...the gap will be closed...and im not talkin bout the one where you buy your jeans from either
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Quoting NICycloneChaser:


Pressure can be deceiving, look at Cat 2 Alex last year, had a pressure of 947mb. Still, 9,64 is a potent hurricane.
My fav cane!
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Quoting MrstormX:


If that even is the center, hard to figure out what is going on right now.


Ya, i've given up forecasting Emily. Im just sitting back and watching the show, letting the experts do there job.

HWRF really deepens it off the coast this run.
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I'll put a lot more stock in the HWRF now that it has received an upgrade.

So far, the HWRF's solution is definitely plausible, IMO.
Member Since: July 6, 2010 Posts: 113 Comments: 32874
Quoting extreme236:


Gettin close to major hurricane status


Yep.. Drops to 959mb next frame. Theoretically a Cat 3, but varies by storm of course.
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Quoting ncstorm:
964 mb..thats almost a category 3


Pressure can be deceiving, look at Cat 2 Alex last year, had a pressure of 947mb. Still, 964 is a potent hurricane.
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Damn.

Moving NE at 114 hours.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting HurricaneSwirl:


964 mb. All you people in SC/NC better hope this recurves sharply, although you look safe in this run so far :P


Gettin close to major hurricane status
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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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