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 HCW:
Latest model runs for Emily. Have a great day :)

Shift west?
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Quoting Seflhurricane:
you just read my mind !!!


:)...great minds think alike....
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Wanna know how warm the water is off the Central Florida coast... according to the NDBC, the current water temperature is 88 degrees at buou 41009- 20 NMI East of Port Canaveral, FL... and at 41010- 120 NMI East of Port Canaveral, FL, the water is 87 degrees. That is warm!
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615. 996tt
Quoting CitikatzSouthFL:


How about everyone puts Lucreto on IGNORE???? He is posting stuff just to get a rise out of folks. That is not polite behaviour in our WU playground. Just saying.


Its part of what makes this entertaining, except when it runs off good people like stormw. I would venture to say most are wishcasters on here. Most would like to be a part of a nice or little cat 1 or 2 or like to watch bigger stuff come in whether they admit it or not. Me, been through some bad ones, but gotta say I could use some nice 20 foot storm swells to surf and dang tourists, traffic, lines and poor cell phone reception has already gotten on mast last nerve so a nice little clear out would be sweet. Haha, I moved to the beach to get away from traffic . . .
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614. HCW
Latest model runs for Emily. Have a great day :)

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Quoting tiggeriffic:


personally wish there was such a thing as a cyber rubberband shooter to ward off the trolls and pop em between the eyes at the same time...
you just read my mind !!!
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Member Since: July 20, 2010 Posts: 0 Comments: 225
Quoting Seflhurricane:
how have you been dewey , seems like we are in the middle of a fire storm


personally wish there was such a thing as a cyber rubberband shooter to ward off the trolls and pop em between the eyes at the same time...
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Quoting stormwatcherCI:
Looks like she tucked her coc back under the convection.


Actually, shear is blowing the convection away as fast as the storm tries to pull it over the top of the center. Take a look at the visible loop and you will see that only a wisp remains of the latest blow up that was trying to cover the center
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Gonzo (G-IV) is out sampling now the Bahamas.

Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 3rd day of the month at 19:10Z
Aircraft: Gulfstream IV-SP (G-IV) (Reg. Num. N49RF)
Storm Number: 05
Storm Name: Emily (flight in the North Atlantic basin)
Mission Number: 9
Observation Number: 03
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Also notice the MLC circulation moving up from the SE very close now the to LLC, Emily is organizing!
Member Since: April 29, 2007 Posts: 0 Comments: 7805
Exposed center, arc clouds to the south east. Hard to believe this thing might survive Hispanola.
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Quoting FLdewey:


Yeah they can't seem to figure that out. Maybe I can post it in Braille.
how have you been dewey , seems like we are in the middle of a fire storm
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Quoting Hurricanes12:
Does the Eastern tip of Cuba have any terrain that would hinder Emily when she passes over it?


Peaks near 1000m on the East tip, but nothing like a brick wall.
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It's all greek to me ... just what does IT mean?? :) Fellow Lauderdale gal here ...
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599. 7544
so we went from a rip emily to a can u believe this ms emily lol
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Quoting Grothar:


thank you for posting that..I have been looking on NWS for projected wave heights and couldnt find it..
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* ATLANTIC SHIPS INTENSITY FORECAST *
* GOES AVAILABLE, OHC AVAILABLE *
* EMILY AL052011 08/03/11 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 45 45 46 47 48 50 56 61 66 68 72 66 61
V (KT) LAND 45 45 46 46 47 47 53 57 63 65 69 63 58
V (KT) LGE mod 45 45 46 46 46 45 48 53 62 69 75 77 74
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 15 12 15 16 17 16 4 5 9 6 6 23 14
SHEAR ADJ (KT) 4 3 4 9 0 -3 -1 -3 2 -1 2 -2 4
SHEAR DIR 267 252 266 266 269 275 12 2 87 44 354 3 360
SST (C) 28.8 28.8 28.9 29.0 29.2 29.4 29.7 29.9 29.5 28.8 28.6 28.0 26.9
POT. INT. (KT) 149 149 151 153 156 159 164 168 160 149 147 140 126
ADJ. POT. INT. 144 142 145 148 151 150 150 151 141 130 130 125 113
200 MB T (C) -52.5 -52.4 -52.2 -52.1 -51.6 -51.8 -51.2 -50.9 -50.4 -50.2 -50.0 -50.3 -50.4
TH_E DEV (C) 10 11 11 11 11 11 10 11 11 10 12 11 10
700-500 MB RH 61 56 56 56 57 54 56 56 57 63 66 63 66
GFS VTEX (KT) 14 12 12 12 11 11 13 13 16 15 18 14 13
850 MB ENV VOR 35 42 35 32 41 35 14 4 4 -29 2 -5 22
200 MB DIV 59 62 60 54 42 8 2 10 28 23 38 18 17
700-850 TADV 5 2 1 15 12 -3 -2 -5 -1 9 6 15 26
LAND (KM) 146 34 28 42 43 76 201 183 67 148 260 277 556
LAT (DEG N) 16.8 17.4 17.9 18.8 19.7 21.8 23.7 25.5 27.3 29.2 31.3 33.1 34.6
LONG(DEG W) 70.3 71.2 72.1 73.2 74.2 76.0 77.2 78.4 79.5 79.3 77.6 74.3 69.9
STM SPEED (KT) 11 10 12 13 13 12 11 10 10 11 14 18 19
HEAT CONTENT 94 86 90 62 81 76 66 3 61 41 44 18 16

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):280/ 13 CX,CY: -12/ 2
T-12 MAX WIND: 45 PRESSURE OF STEERING LEVEL (MB): 680 (MEAN=623)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 29.6 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 44.0 (MEAN=65.0)

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
-------------------------------------------------- --------
SAMPLE MEAN CHANGE 1. 2. 3. 4. 6. 8. 9. 11. 12. 12. 13. 13.
SST POTENTIAL 1. 2. 3. 4. 7. 10. 14. 16. 18. 19. 19. 18.
VERTICAL SHEAR MAG 0. 0. 1. 1. 1. 3. 5. 6. 7. 8. 7. 6.
VERTICAL SHEAR ADJ 0. 0. -1. -1. -1. 0. 0. 0. 0. 0. 0. 0.
VERTICAL SHEAR DIR 0. -1. -2. -2. -3. -3. -4. -4. -4. -5. -5. -5.
PERSISTENCE 0. -1. -1. -1. -1. -1. -1. -1. -1. 0. 0. 0.
200/250 MB TEMP. 0. 0. -1. -1. -2. -3. -4. -6. -7. -8. -10. -11.
THETA_E EXCESS 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 0.
700-500 MB RH 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1.
GFS VORTEX TENDENCY 0. -1. -1. -2. -2. -1. -2. 1. 0. 2. -2. -3.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. -1.
200 MB DIVERGENCE 0. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. 0.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. -1.
ZONAL STORM MOTION 0. 0. 1. 1. 2. 2. 2. 2. 3. 3. 3. 3.
STEERING LEVEL PRES 0. 0. 0. 0. -1. -1. -1. -1. -1. -1. -1. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. 0. -1.
GOES PREDICTORS -1. -2. -3. -3. -3. -3. -2. -2. -1. -1. -1. -1.
OCEAN HEAT CONTENT 0. 1. 1. 1. 1. 1. 0. 0. 0. 0. 0. 0.
-------------------------------------------------- --------
TOTAL CHANGE 0. 1. 2. 3. 5. 11. 16. 21. 23. 27. 21. 16.

** 2011 ATLANTIC RI INDEX AL052011 EMILY 08/03/11 18 UTC **

12 HR PERSISTENCE (KT): 0.0 Range:-45.0 to 30.0 Scaled/Wgted Val: 0.6/ 2.0
850-200 MB SHEAR (KT) : 14.9 Range: 26.2 to 3.2 Scaled/Wgted Val: 0.5/ 0.9
STD DEV OF IR BR TEMP : 29.6 Range: 34.1 to 3.2 Scaled/Wgted Val: 0.1/ 0.3
D200 (10**7s-1) : 55.4 Range:-21.0 to 165.0 Scaled/Wgted Val: 0.4/ 0.9
POT = MPI-VMAX (KT) : 100.9 Range: 33.8 to 126.5 Scaled/Wgted Val: 0.7/ 0.8
850-700 MB REL HUM (%): 67.6 Range: 56.0 to 85.0 Scaled/Wgted Val: 0.4/ 0.2
Heat content (KJ/cm2) : 82.6 Range: 0.0 to 130.0 Scaled/Wgted Val: 0.6/ 0.0
% area w/pixels <-30 C: 37.0 Range: 17.0 to 100.0 Scaled/Wgted Val: 0.2/ 0.1

Prob of RI for 25 kt RI threshold= 18% is 1.4 times the sample mean(12.8%)
Prob of RI for 30 kt RI threshold= 11% is 1.3 times the sample mean( 8.4%)
Prob of RI for 35 kt RI threshold= 2% is 0.3 times the sample mean( 5.0%)
Prob of RI for 40 kt RI threshold= 1% is 0.3 times the sample mean( 3.4%)

## ANNULAR HURRICANE INDEX (AHI) AL052011 EMILY 08/03/11 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL052011 EMILY 08/03/2011 18 UTC **
TIME(HR) 0-12 12-24(0-24) 24-36(0-36) 36-48(0-48)
CLIMO(%) 0 0( 0) 0( 0) 0( 0) <-- PROB BASED ON INTENSITY ONLY
PROB(%) 0 0( 0) 0( 0) 0( 0) <-- FULL MODEL PROB (RAN NORMALLY)
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Quoting KEEPEROFTHEGATE:
05L/TS/E
MARK
16.90N/70.13W
Looks like she tucked her coc back under the convection.
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Quoting TropicalAnalystwx13:


Please...Just:


This one is too dangerous to just /ignore, as he uses made up models and tells people to ignore storms. Folks finding this blog for the first time might believe his poison.
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Quoting WPBHurricane05:
Thunderstorms are collapsing around the center. Conditions are still unfavorable for any strengthening before Haiti landfall. Will be interesting to see whats left tomorrow night.


Agree. Dry Air and some southerly shear is currently inhibiting Emily from strengthening. Like I said earlier today, Emily will probably become an open wave by tomorrow night.
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593. Jax82
IMO, i bet she'll start turning when she gets to the west of that Southern point of Hispanoila that divides the country.
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Big change in the SHIPS. DSHPS and LGEM show no weakening during the next couple days. Must not be as much land interaction on this run. Link
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Quoting extreme236:
It would definitely be something for this strange and disorganized cyclone to make it past Hispanola and up to a hurricnae.
very hot water in the bahamas and off the east coast of florida, many systems have gone from a TS to hurricane status rather quickly
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Quoting Hurricanes12:
Does the Eastern tip of Cuba have any terrain that would hinder Emily when she passes over it?


Eastern Cuba is highly mountainous.
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Quoting Torgen:


So, the gate to the Gulf has been closed?
No. He is saying the model is showing a storm there
Member Since: December 1, 2006 Posts: 2 Comments: 3619
I have an idea-- instead of wishcast how bout westcast and eastcast. It's more easily understandable and a lot less offensive. Back to lurking until midnight-ish.
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Quoting msgambler:
Levi, what is the BAM suite? I have noticed for the last few days that it has been almost spot on with EM. I don't remember BAM being that reliable last year.


It's short for the Beta and Advection Model. It is basically a steering layer model, producing forecasts based on vertically-averaged winds out to 120 hours. The BAMS depicts the shallow layer, the BAMM the medium layer, and BAMD the deep layer flow. The BAM forecasts also include the "Beta Effect" as a parameter, the effect of increasing Coriolis force with latitude that causes relative vorticity asymmetry about the storms's circulation. Basically, all this does is cause the storm to move more northwestward the farther north it goes.
Member Since: November 24, 2005 Posts: 635 Comments: 26585
Quoting Hurricanes12:
Does the Eastern tip of Cuba have any terrain that would hinder Emily when she passes over it?
yes has alot of mountains not as large as hispaniola
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It would definitely be something for this strange and disorganized cyclone to make it past Hispanola and up to a hurricnae.
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05L/TS/E
MARK
16.90N/70.13W
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this sort of reminds me of ike. they had it going out to sea and then model run after model run brought it more west. I'm looking forward to seeing model runs with G-IV data
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Does the Eastern tip of Cuba have any terrain that would hinder Emily when she passes over it?
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Quoting MiamiHurricanes09:
I don't like the location of the weakness.
yeah i see right over the florida Se coast to grand bahama
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For those interested in learning more about the models, here is a web based video TC Track Model Guidance used by NHC
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Quoting Levi32:
12z UKMET has a closed isobar southeast of the keys.



So, the gate to the Gulf has been closed?
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the more people quote lucredo the crazier things he says
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Quoting chevycanes:


pretty clear there is a break in the ridge and it should turn WNW-NW very soon.
I don't like the location of the weakness.
Member Since: September 2, 2009 Posts: 130 Comments: 21098

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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.