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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So if Emily stalled, that could mean that the predicted turn to the NW is about to start. If that's not the case then I wonder if it will get pull NW at all.
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1719. WxLogic
...EMILY STALLS...STILL PRODUCING HEAVY RAIN OVER HISPANIOLA...

8:00 PM EDT Wed Aug 3
Location: 16.9°N 70.6°W
Max sustained: 50 mph
Moving: Stationary
Min pressure: 1004 mb
Member Since: Posts: Comments:
Atlantic ACE:

Arlene (TS): 1.63
Bret (TS): 2.95
Cindy (TS): 1.84
Don (TS): 1.50
Emily (TS): 1.38 (Ongoing)
-------
Total: 9.29 (Up to 8/3/2011)

Eastern Pacific ACE:

Adrian (C4): 11.9
Beatriz (C1): 3.00
Calvin (C1): 2.43
Dora (C4): 14.7
Eugene (C4): 8.66 (Ongoing)
--------
Total: 40.6 (Up to 8/3/11)
Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting TropicalAnalystwx13:


And I posted it second ;)


both of you posted after me....
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Question, I just logged back in from being away all day at work. What is emily doing now and should I worry if in Jax, NE Florida? Back to lurking...
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Quoting kmanislander:
There is the stall I posted about LOL


Hi Kman,

Great to see you back! What do you think this means? NHC says an initial westward track with a turn to WNW/NW, they are very hung up on this NW turn that has not materialized , just saying
Member Since: April 29, 2007 Posts: 0 Comments: 7862
Quoting GTcooliebai:
sigh...Emily has stalled. One very weird storm she continues to be.
she might as well move southeast at 1 mph the the next advisory to complete the limbo she has been doing.
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Quoting BahaHurican:
I'm starting to think they didn't do the 5th vortfix because the centre had moved so little since their last passthrough....


Yes, the stall was to be expected based upon the collapsed steering regime. The next move will likely be either to the W or the WNW.
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Quoting DoubleAction:
This is nuts. Now the GFS ie. NHC shows Emily hitting a wall and bouncing north. The trough is not that strong and Emily is not that strong. I expect a gradual turn clipping Hispaniola then slow development and a turn into the weakness. This thing is still trucking WNW.


This thing is now stationary, I'm afraid. Models have been all over the place with Emily, and with the whole season so far, it must be said.
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Quoting TropicalAnalystwx13:
Muifa has been undergoing a lot of Eyewall Replacement Cycles (EWRC) lately. Must not have been satisfied with the pinhole eye it had the other day.







Ya that was just insane, easily rivaled Wilma's intensity IMO.

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Sorry my typo, has anyone posted about the swirl at 21 69?
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I'm starting to think they didn't do the 5th vortfix because the centre had moved so little since their last passthrough....

Edit: Looks like I was right, given the 8 p.m. update... lol
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This is nuts. Now the GFS ie. NHC shows Emily hitting a wall and bouncing north. The trough is not that strong and Emily is not that strong. I expect a gradual turn clipping Hispaniola then slow development and a turn into the weakness. This thing is still trucking WNW.
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1705. hotrods
So what could be next if she has stalled?
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Stormpetrol,
Rainfall rate is still slightly too high for recon to consider using this dropsonde for the NHC, and 55 mph is not used in advisories due to it being 47.5 knots(they dont use it becuase it would make it difficult for them to say its a 55 mph, because of it being between 45 to 50 knots...) So they would have to find 60 mph that arent with a rainfall rate higher than .5 inches per hr, and not denoted as suspect...
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Quoting Seflhurricane:
so its a slight NE relocation and not by much and it appears she is meandering which coincides with what the current steering maps indicate
she better hit that gap soon for those who want that result or else it's west by west young lady
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sigh...Emily has stalled. One very weird storm she continues to be.
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Emily doesn't have a clue where she wants her centre to be. Could well be (pretty much) stationary. Longer she sits there, the more time for the high pressure to build in before she's clear of the CONUS East Coast.
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1700. JLPR2
I see the GFS is saying CV storm by mid month. Well we are heading into the heart of the season, so not surprising at all if it materializes.

Keeping an eye on this:


I see Emily is staying south of the DR, I hope it makes the turn further ahead, don't want to see it in Haiti.
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Quoting WeatherNerdPR:

Hey! I posted it first!


And I posted it second ;)
Member Since: July 6, 2010 Posts: 113 Comments: 32072
can someone please post the 18Z models, have they shifted west again or remained
Member Since: July 14, 2009 Posts: 0 Comments: 3022
I have a question.

How important is the location of the storm in the hurricane models? It seems to me that the close tracking of starting and ending positions of a storm in a particular time period is important in evaluating which models are accurately predicting the weather factors that steer the storm.

But, if a storm gets torn apart and then assembles a hundred miles away, does that significantly affect the predicted location a few days out?

Sorry if this is a dumb question.
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Quoting TropicalAnalystwx13:
...EMILY STALLS...STILL PRODUCING HEAVY RAIN OVER HISPANIOLA...


SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...16.9N 70.6W
ABOUT 75 MI...125 KM SE OF ISLA BEATA DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...STATIONARY
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES
Quoting Hurricanejer95:
...EMILY STALLS...STILL PRODUCING HEAVY RAIN OVER HISPANIOLA...
8:00 PM EDT Wed Aug 3
Location: 16.9°N 70.6°W
Max sustained: 50 mph
Moving: Stationary
Min pressure: 1004 mb

Hey! I posted it first!
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Quoting jonelu:
Honestly Im "wishcasting" it north towards FL now. We could use the rain...badly. As long as she is a TS...BRING IT!
that's what I thought,got friends in SW Florida saying it's bone dry and need a couple depressions/trp storms to get back to even, kinda like texas,but not as severe
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Quoting TropicalAnalystwx13:
Another image of Eugene.



Weakening finally
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There is the stall I posted about LOL
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...EMILY STALLS...STILL PRODUCING HEAVY RAIN OVER HISPANIOLA...
8:00 PM EDT Wed Aug 3
Location: 16.9°N 70.6°W
Max sustained: 50 mph
Moving: Stationary
Min pressure: 1004 mb
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:
What's with all these beautiful Eastern Pacific storms so far this season?

Hurricane Adrian:



Hurricane Dora:



Hurricane Eugene:

It's to balance off all the nasty-looking ones we've had on this side of Central America.... lol
Member Since: Posts: Comments:
...EMILY STALLS...STILL PRODUCING HEAVY RAIN OVER HISPANIOLA...


SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...16.9N 70.6W
ABOUT 75 MI...125 KM SE OF ISLA BEATA DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...STATIONARY
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES
Member Since: July 6, 2010 Posts: 113 Comments: 32072
...EMILY STALLS...STILL PRODUCING HEAVY RAIN OVER HISPANIOLA...
8:00 PM EDT Wed Aug 3
Location: 16.9°N 70.6°W
Max sustained: 50 mph
Moving: Stationary
Min pressure: 1004 mb
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18z GFDL should be starting up any second here.
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AT 800 PM EDT...0000 UTC...THE CENTER OF TROPICAL STORM EMILY WAS
LOCATED BY AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT NEAR
LATITUDE 16.9 NORTH...LONGITUDE 70.6 WEST. EMILY HAS MOVED LITTLE
OVER THE PAST FEW HOURS...BUT IS EXPECTED TO RESUME A WESTWARD
MOTION OF ABOUT 14 MPH...22 KM/H IN THE NEXT FEW HOURS. A GRADUAL
TURN TO THE WEST-NORTHWEST AND NORTHWEST IS EXPECTED DURING THE
NEXT DAY OR SO. ON THIS TRACK...THE CENTER OF EMILY WILL MOVE
ACROSS THE SOUTHWESTERN PENINSULA OF HAITI EARLY THURSDAY AND MOVE
OVER EXTREME EASTERN CUBA THURSDAY NIGHT.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 50 MPH...85 KM/H...WITH HIGHER
GUSTS. SOME WEAKENING IS POSSIBLE AS EMILY INTERACTS WITH THE HIGH
TERRAIN OF HAITI AND EASTERN CUBA. SOME RE-STRENGTHENING IS
POSSIBLE WHEN THE CYCLONE MOVES OVER THE BAHAMAS.

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

THE LATEST MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE
RECONNAISSANCE PLANE WAS 1004 MB...29.65 INCHES.
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Muifa has been undergoing a lot of Eyewall Replacement Cycles (EWRC) lately. Must not have been satisfied with the pinhole eye it had the other day.





Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting TropicalAnalystwx13:
Another image of Eugene.

amazing, look at the symmetry of the eye, almost perfect, is this what you call an angular hurricane?
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1684. hotrods
the 8:00 pm is out, don't know how to post it but emily has stalled.
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Quoting MiamiHurricanes09:
They're still in there. New page of data has them still flying at 842/3mb towards the southeast.


Just saw that.
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FULL STALL
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Quoting kmanislander:


If the base is St Croix that would make sense. We will know when the next page of data downloads as the aircraft height will reflect a climb out.


I edited my origonal post, they have another 1/2 hour to go per the schedule.
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Quoting kmanislander:


If the base is St Croix that would make sense. We will know when the next page of data downloads as the aircraft height will reflect a climb out.
They're still in there. New page of data has them still flying at 842/3mb towards the southeast.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting MiamiHurricanes09:
Run complete; 126 hours.



Thanks so much for posting these. Very informative! (and as a NCer breathing a bit easier). Time will tell.
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Quoting GTcooliebai:
or head back east, like one Blogger said with Don.
I'm beginning to wonder anymore!
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Another image of Eugene.

Member Since: July 6, 2010 Posts: 113 Comments: 32072
HHs turning S again looks like anyway
Member Since: April 29, 2007 Posts: 0 Comments: 7862
Quoting nrtiwlnvragn:


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


If the base is St Croix that would make sense. We will know when the next page of data downloads as the aircraft height will reflect a climb out.
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Quoting LBAR:
Obvious swirl in Bay of Campeche...although very small may it bring rain to Texas!


Don't count on this:



To bring Texas any measurable rainfall, if any.
Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting stormpetrol:
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


Probably not, as flight level winds are much lower than the surface level winds in that reading. NHC usually instantly throws those readings out when that happens.
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Just wanted to look at our local guy... basically just said to expect deteriorating conditions in the SE Bahamas tomorrow. My cousins and the other guys from the settlement of Pirates Well, Mayaguana actually went fishing today. Apparently the wx was pretty good down there...
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Quoting tropicalweather2011:


The models might say that, but Emily is moving due west. We rely too much on computers now days.
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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:


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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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