High wind shear disrupts Emily as it approaches Hispaniola

By: Dr. Jeff Masters , 5:06 PM GMT on August 03, 2011

Share this Blog
26
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 520 - 470

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41Blog Index

Member Since: Posts: Comments:
Quoting weatherman566:
I'm not impressed with Emily at the moment. I agree with Levi, very asymmetrical system. She might be trying to organize, but the southerly shear will get her again. Plus, the mountains over Hispaniola will hinder or hurt Emily more. The key to this forecast is:

How far west will she travel until she begins to move NW?

Will Emily hold together when she moves through Hispaniola?

I don't expect her to strengthen much at all today, not after looking at the current conditions.

Don't let the lower pressure and increase of convection fool you.


Lets see, Lower preasure an increase in convection but she won't strengthen today? HMmmm
Member Since: Posts: Comments:
Pinhole eye! LOL
Member Since: Posts: Comments:
Quoting patrikdude2:
52 knots
(~ 59.8 mph)


Highly questionable.
Member Since: June 9, 2007 Posts: 4 Comments: 15947
Member Since: Posts: Comments:
Quoting stormhank:
Could someone give me a link to the vortex messages site..thanks!!


Link
Member Since: Posts: Comments:
Whoa buddy! Flight level winds were a lot below SFMR winds though.

184900 1548N 06939W 8441 01544 0102 +146 +079 185025 029 052 018 00
Member Since: September 2, 2009 Posts: 130 Comments: 21194


Nice wave coming off Africa
Member Since: Posts: Comments:
Member Since: Posts: Comments:
HH found winds 52 knots
(~ 59.8 mph)
Member Since: Posts: Comments:
507. 7544
oh hmmm back to where the first cone wes this might be the cone at 5pm
Link
Member Since: Posts: Comments:
Quoting stormhank:
Could someone give me a link to the vortex messages site..thanks!!
http://www.nhc.noaa.gov/reconlist.shtml
Member Since: September 2, 2009 Posts: 130 Comments: 21194
I doubt the NHC will move anything, the TVCN maintained at 18Z.

Member Since: Posts: Comments:
Member Since: Posts: Comments:
Could someone give me a link to the vortex messages site..thanks!!
Member Since: Posts: Comments:
Emily looks like she's thinking about that turn to a WNW heading.
Member Since: Posts: Comments:
Cone about the same for 2pm. Looks like some convection trying to re-fire around COC. She's tenacious...
Member Since: Posts: Comments:


center getting covered fast, Emily pulling one the hat this afternoon!Very interesting storm indeed
Member Since: Posts: Comments:
497. DVG
Thx BayouB for pointing that out.

I like reed's track. Because Em's making a run at strengthening again, I think the turn north isn't too far off. At about 20N it looks like Em will sorta dodge most of Cuba and Hispaniola.

Will look forward to what everyone has to say from there on.
Member Since: Posts: Comments:
Quoting OUSHAWN:
Key word there is should...just like Emily should have already been going the NW route.
I miss the old days,when we had no idea where they were going.
Member Since: Posts: Comments:
18z Suite

FULL IMAGE

Models have this moving NW when it's heading WNW or W.

Member Since: June 9, 2007 Posts: 4 Comments: 15947
somehow I doubt it will reach category 3 strength
Member Since: Posts: Comments:
Not bad at all.

000
URNT12 KNHC 031850
VORTEX DATA MESSAGE AL052011
A. 03/18:20:40Z
B. 16 deg 47 min N
070 deg 24 min W

C. 850 mb 1465 m
D. 44 kt
E. 050 deg 48 nm
F. 138 deg 41 kt
G. 048 deg 77 nm
H. 1003 mb
I. 17 C / 1517 m
J. 21 C / 1520 m
K. 10 C / NA
L. NA
M. NA
N. 1345 / 08
O. 0.02 / 1 nm
P. AF306 0805A EMILY OB 04
MAX FL WIND 41 KT NE QUAD 17:51:20Z
MAX FL TEMP 21 C 325 / 6 NM FROM FL CNTR
;
Member Since: September 2, 2009 Posts: 130 Comments: 21194
490. Hugo7
Anyone got anything on the blob that moved into the gulf?
Member Since: Posts: Comments:
Still seems to be a bit of shear over top of the center at the moment, albeit seems to be less than a few hours ago. WWD motion for the next 6 hours probably then WNW-NW over the Tiburon Peninsula and into the Windward Passage and southeastern Cuba.
Member Since: Posts: Comments:
Time: 18:40:00Z
Coordinates: 16.0333N 69.65W
Acft. Static Air Press: 843.7 mb (~ 24.91 inHg)
Acft. Geopotential Hgt: 1,548 meters (~ 5,079 feet)
Extrap. Sfc. Press: 1009.0 mb (~ 29.80 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 202° at 26 knots (From the SSW at ~ 29.9 mph)
Air Temp: 16.4°C (~ 61.5°F)
Dew Pt: 9.5°C (~ 49.1°F)
Peak (10s) Flt. Lvl. Wind: 27 knots (~ 31.0 mph)
SFMR Peak (10s) Sfc. Wind: 40 knots (~ 46.0 mph)
SFMR Rain Rate: 14 mm/hr (~ 0.55 in/hr)
(*) Denotes suspect data
Member Since: Posts: Comments:
Anticyclone expanding in size, providing some air for Emily to breath. This is the updated CIMMS shear map, wind shear decreasing a bit to the north of Emily, which is why re-organization is happening.

Member Since: Posts: Comments:
Quoting lucreto:
I believe RECON is having equipment issues so the NHC might abort the flight and disregard all information gathered.


Goodbye! Poof! Adios!
Member Since: Posts: Comments:
Keep in mind everyone... The weaker Emily stays the further west she will track before getting picked up by the trough. She will really need to deepen for the far easterly solutions to verify. Still too early to say whether the E.Coast is in the clear. Let's see how she does crossing the mountains...
Member Since: Posts: Comments:
Quoting lucreto:


I currently have a self-imposed 2011 tropical season ban, if Emily is ever classified a tropical storm in the Gulf of Mexico.

No your self ban was if it hit Florida as per your post 1 or 2 days ago...Ill be sure to remind you again if you try to re-negotiate.
Member Since: Posts: Comments:
1003mb (Surface) 27.8°C (82.0°F) 26.4°C (79.5°F)
931mb 23.6°C (74.5°F) 23.0°C (73.4°F)
871mb 21.6°C (70.9°F) 20.3°C (68.5°F)
850mb 21.8°C (71.2°F) Approximately 16°C (61°F)
843mb 21.4°C (70.5°F) Approximately 10°C (50°F)
Member Since: Posts: Comments:
Quoting gaweatherboi:
Well on another note....its HOT!!! Millen, GA 102F feels like 110F Dewpoint 70F


Hey Millen, Statesboro here.
Member Since: Posts: Comments:
Quoting Jedkins01:
Lucreto is just being a jerk, trying to start trouble. Don't feed his/her appetite for attention. That's what the main goal is for the immature and trouble makers. They just want to get negative attention and ruin other peoples day. Don't give in!


That's why some people don't go to the ignore list.

Once there, you lose the ability to "!" the more stupid and misleadiing statements he makes.
Member Since: Posts: Comments:
Quoting lucreto:
I believe RECON is having equipment issues so the NHC might abort the flight and disregard all information gathered.


Ummm, where are you getting all those theories.
Member Since: Posts: Comments:
Quoting lucreto:
I believe RECON is having equipment issues so the NHC might abort the flight and disregard all data gathered.


I must say you're excellent at what you do, lmao!!!
Member Since: Posts: Comments:
Interesting statement on Dropsonde data

Dropsonde Location: Dropped in eye.


She has an eye?
Member Since: Posts: Comments:
I'm not impressed with Emily at the moment. I agree with Levi, very asymmetrical system. She might be trying to organize, but the southerly shear will get her again. Plus, the mountains over Hispaniola will hinder or hurt Emily more. The key to this forecast is:

How far west will she travel until she begins to move NW?

Will Emily hold together when she moves through Hispaniola?

I don't expect her to strengthen much at all today, not after looking at the current conditions.

Don't let the lower pressure and increase of convection fool you.
Member Since: Posts: Comments:
I do notice that Emily started this trek through the CAR at 15N and is currently almost at 17N.... but no Nward movement seen, I agree.....


Don't be surprised if Emily does in fact make that right turn sometime during the next 12 hours.... west of the original forecast, which makes it potentially more dangerous in a variety of ways for the Bahamian archipelago.

We still have to see what shape the system is in tomorrow before we can speculate with any seriousness on FL impacts... but right now still looking relatively low.

Member Since: October 25, 2005 Posts: 19 Comments: 22687
Quoting WxLogic:


Sure is... of course we know that won't happen.


dont be so sure..I aint counting nothing out..even that curve..
Member Since: August 19, 2006 Posts: 13 Comments: 16215
Well on another note....its HOT!!! Millen, GA 102F feels like 110F Dewpoint 70F
Member Since: Posts: Comments:

Viewing: 520 - 470

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Light Snow
29 °F
Light Snow