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 MississippiWx:


The weakness hasn't changed much the last 6 hours or so. It's there and she has finally reached a longitude where it will effect her.


but according to a lot of the data, Emily isnt stacked enough to really feel it...even the mets on TV said that all the models predicted emily would be stronger by now to be affected...
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Quoting charlottefl:
CURRENT STEERING:






3 HOURS PREVIOUS:



6 HOURS PREVIOUS:



Ridge building westward.


All the while, the weakness is still there.
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HH27 - post 1264 - I saw it, too; slight jog WSW
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Quoting floodzonenc:
Yeah b/c w/o the "P", you would be "cola dan".  Actually as hot as it's been, that would be an improvement :P


Quoting PcolaDan:




So, I would be a better person in the heat if I lose my P. ;>)
Member Since: August 22, 2008 Posts: 12 Comments: 6010


Eyewall of Typhoon Muifa on top of Okinawa
Member Since: September 18, 2010 Posts: 0 Comments: 5136
CURRENT STEERING:






3 HOURS PREVIOUS:



6 HOURS PREVIOUS:



Ridge building westward.
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Quoting KEEPEROFTHEGATE:
05L/TS/E
MARK
17.00N/70.33W
Watching that i think i see LLC moving WWSWW or west with i tiny little hint of southern motion.
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1263. WxLogic
Quoting atmoaggie:
Really, I doubt it to be drastically different.
Hopefully the improvement is real, though.

A thought about that, though, is that these models are always being upgraded and biases changing. Coherently using them as guidance in a forecast situation requires us to be informed as to the changes and their effects. Otherwise, in this particular case, some forecaster would possibly account for a bias in the HWRF (they maybe had noticed in past situations) that no longer exists in it's current form.


Quite true.
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Quoting OUSHAWN:


There is no WNW motion I see here...just continued straight W.
It's definitely somewhat north of west, but not much.
Member Since: December 1, 2006 Posts: 2 Comments: 3619
Quoting tiggeriffic:


you are posting that it is opening up, yet a few other people posted the same pic and said the gap is closing...now i am thoroughly confused and cross eyed


The weakness hasn't changed much the last 6 hours or so. It's there and she has finally reached a longitude where it will effect her.
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1258. j2008
Quoting KEEPEROFTHEGATE:
05L/TS/E
MARK
17.00N/70.33W

The last frame, Emilys LLC gets tucked under convection again. Impressive.
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Local met. Dennis Phillips just said if this thing continues tracking west for another day, then the track is wrong, since the NHC has been forecasting a turn to the north which hasn't happened yet, and Emily would come closer to FL. So it looks like it is a wait and see.
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1256. OUSHAWN
Quoting KEEPEROFTHEGATE:
05L/TS/E
MARK
17.00N/70.33W


There is no WNW motion I see here...just continued straight W.
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Quoting hyperanthony:
How long will we need to give to tell if Emily is going to go north into the weakness or continue westward? The models seem pretty well split on the matter.


The models aren't split. The dynamic models are all rather close in that they turn Emily to the NW. I would go with that any day. Emily is still a 1003mb low with a closed circulation, rather shallow but the dynamic models should be able to handle her. Either way, I'd bet on the dynamic models over the Bams and stat models in the first 48hrs of the forecast any day. I think its just a matter of time in that Emily makes a turn. And yes, Emily could turn on a dime! That is real quick!
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1254. GetReal
1244. MississippiWx 9:44 PM GMT on August 03, 2011
Weakness is plenty big enough for her to go towards now. The latest center fixes from recon seem to show that she is following the steering map now. A WNW motion should be more common


If only that azores high would stop ridging westward with emily....
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Quoting tiggeriffic:


you are posting that it is opening up, yet a few other people posted the same pic and said the gap is closing...now i am thoroughly confused and cross eyed
so am i!
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1252. K8eCane
Quoting zoomiami:


You know one of the issues of when and where to post the warnings have to do with the economics. There was an article that I saw that had the cost by miles. Five years ago they would have posted warnings from Miami to West Palm in this type of scenario -- they didn't have the sophistication with the tracking systems. Now they will post the warnings/watches for as small an area as just Miami Dade County.

Not saying that they don't post because of the economics, but they try to be cautious to not overextend the warning area.


Theres a lot of money in them hotels and motels and restaurants etc
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Quoting MississippiWx:
Weakness is plenty big enough for her to go towards now. The latest center fixes from recon seem to show that she is following the steering map now. A WNW motion should be more common.



you are posting that it is opening up, yet a few other people posted the same pic and said the gap is closing...now i am thoroughly confused and cross eyed
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1249. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #72
TYPHOON MUIFA (T1109)
6:00 AM JST August 4 2011
==========================================

SUBJECT: Category Four Typhoon In Sea South Of Japan

At 0:00 AM UTC, Typhoon Muifa (945 hPa) located at 24.6N 130.1E has 10 minute sustained winds of 85 knots with gusts of 120 knots. The cyclone is reported as moving west at 8 knots

Dvorak Intensity:

Storm Force Winds
=================
110 NM from the center in north quadrant
90 NM from the center in south quadrant

Gale Force Winds
=================
300 NM from the center in northeast quadrant
200 NM from the center in southwest quadrant

Forecast and Intensity
========================
24 HRS: 24.9N 127.5E - 85 knots (CAT 4/Very Strong Typhoon)
45 HRS: 26.1N 125.4E - 85 knots (CAT 4/Very Strong Typhoon)
69 HRS: 28.2N 122.9E - 75 knots (CAT 3/Strong Typhoon)
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1248. KEEPEROFTHEGATE (Mod)
05L/TS/E
MARK
17.00N/70.33W
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting atmoaggie:

Berlioz: "Time is a great teacher, but unfortunately kills all its pupils."


Great one!
Member Since: April 29, 2007 Posts: 0 Comments: 7692
Wishcasting for Texas. Those lakes and rivers need filling.
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Weakness is plenty big enough for her to go towards now. The latest center fixes from recon seem to show that she is following the steering map and a WNW motion should be more common.

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Quoting WxLogic:


Can't wait to see the 18Z HWRF now... :)
Really, I doubt it to be drastically different.
Hopefully the improvement is real, though.

A thought about that, though, is that these models are always being upgraded and biases changing. Coherently using them as guidance in a forecast situation requires us to be informed as to the changes and their effects. Otherwise, in this particular case, some forecaster would possibly account for a bias in the HWRF (they maybe had noticed in past situations) that no longer exists in it's current form.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
1242. emcf30
Quoting charlottefl:


The NHC isn't gonna jump to make a drastic change in track, especially when it's effects in FL are 3 days off. I think they're waiting to see what happens in the environment this evening, and then you may see track changes beginning at 11PM.(Gradual ones)


I totally agree with you Charlottefl. When any type of watches and warnings are issued it cost a ton of money to the local government agencies. I believe they are awaiting data to be inputted from the gulfstream research flight and the current HH mission. There is still plenty of time to post adequate advisories. additionally, the local news agencies are doing a good job of relaying the potential upcoming threat in the areas that could be effected.
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Quoting Jedkins01:



Well I am going to school for meteorology, and there is so much we learn about the atmosphere, and I am just getting started. I think we are too expected to follow the computers every move rather than using our education to make our own judgments when the computers are obviously off. I have seen the NHC do it before, but there are less forecasters that think for themselves and too many that follow model protocol.

Computer models are designed to solve all the massive amounts of equations in a short time and create forecast plots to help us understand what might occur in the future, but the models were not designed to do the forecast for us, so that we must follow the models always. Like I said, we shouldn't throw them out the window, that is just stupid, they are a huge aid to meteorologists. But there is a fine line between using models to help make a forecast and following everything they do.

I mean, I'm not trying to be critical at all, Ive just always been a "outside the box" kind of person.

On the other hand, maybe there's a lot yet I don't understand that goes into play once you have a job as a meteorologist and lives and property are at stake based on what I or my peers forecast.

Maybe the situation of being a professional meteorologists just is a completely different situation and I would be just as conservative. Maybe they want to make sure they don't take on the "boy who cried wolf" appearance that weather forecasters have been looked at for being quick to forecast a change.

I don't know, I don't want to be a know it all, or act like I have better solutions, I'm just talking, and there is much more knowledge and wisdom to acquire in my life as I get older, I am only 20, after all.


You're a smart young man , I understand exactly where you're coming from, also I'm not criticizing the NHC, they do one heck of a good job, they often find themselves between a rock and a hard place, I'm just saying kinda hard to believe the same story when you've heard for days and it ain't happening, not that it won't :)
Member Since: April 29, 2007 Posts: 0 Comments: 7692
Could someone please post where I could find some good wind sheer charts? Specifically 500mb, and to the west of the storm. Thank you :)
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Quoting stormpetrol:


More models jumping now on the western track
The CMC is intriguing me lol.
Member Since: December 1, 2006 Posts: 2 Comments: 3619
Quoting Jedkins01:



Well I am going to school for meteorology, and there is so much we learn about the atmosphere, and I am just getting started. I think we are too expected to follow the computers every move rather than using our education to make our own judgments when the computers are obviously off. I have seen the NHC do it before, but to me it appears that there are less forecasters that think for themselves and too many that follow model protocol.

Computer models are designed to solve all the massive amounts of equations in a short time and create forecast plots to help us understand what might occur in the future, but the models were not designed to do the forecast for us, so that we must follow the models always. Like I said, we shouldn't throw them out the window, that is just stupid, they are a huge aid to meteorologists. But there is a fine line between using models to help make a forecast and following everything they do.

I mean, I'm not trying to be critical at all, Ive just always been a "outside the box" kind of person.

On the other hand, maybe there's a lot yet I don't understand that goes into play once you have a job as a meteorologist and lives and property are at stake based on what I or my peers forecast.

Maybe the situation of being a professional meteorologists just is a completely different situation and I would be just as conservative. Maybe they want to make sure they don't take on the "boy who cried wolf" appearance that weather forecasters have been looked at for being quick to forecast a change.

I don't know, I don't want to be a know it all, or act like I have better solutions, I'm just talking, and there is much more knowledge and wisdom to acquire in my life as I get older, I am only 20, after all.
very well said.
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Quoting hurricanehunter27:
If it takes the southern most models Emily will have a 12 hour plus period to get very strong near cuba beacuse of the high water temps (hotest in the carribian) and very low wind shear.


This actually answered my question as well -- thanks! Hopefully it'll be a good rainmaker and not much else!
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Quoting Jedkins01:



Well I am going to school for meteorology, and there is so much we learn about the atmosphere, and I am just getting started. I think we are too expected to follow the computers every move rather than using our education to make our own judgments when the computers are obviously off. I have seen the NHC do it before, but there are less forecasters that think for themselves and too many that follow model protocol.

Computer models are designed to solve all the massive amounts of equations in a short time and create forecast plots to help us understand what might occur in the future, but the models were not designed to do the forecast for us, so that we must follow the models always. Like I said, we shouldn't throw them out the window, that is just stupid, they are a huge aid to meteorologists. But there is a fine line between using models to help make a forecast and following everything they do.

I mean, I'm not trying to be critical at all, Ive just always been a "outside the box" kind of person.

On the other hand, maybe there's a lot yet I don't understand that goes into play once you have a job as a meteorologist and lives and property are at stake based on what I or my peers forecast.

Maybe the situation of being a professional meteorologists just is a completely different situation and I would be just as conservative. Maybe they want to make sure they don't take on the "boy who cried wolf" appearance that weather forecasters have been looked at for being quick to forecast a change.

I don't know, I don't want to be a know it all, or act like I have better solutions, I'm just talking, and there is much more knowledge and wisdom to acquire in my life as I get older, I am only 20, after all.


I go to ULM for meteorology (if you go to FSU as your photo suggests then you'll know who ULM is after the first football game) and my professors have been stressing the fact that models are no where near perfect. Data points are too far apart and they make major generalizations in their forecasts. We have been told to look at all the models, look at what is currently happening and try our best to forecast what should happen. I am by far no NHC meteorologist but looking at how Emily has acted and how the models have done with her- that extreme turn to the north is something I never would forecast personally but as I said- I am by far no way an expert.
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1234. robj144
Quoting atmoaggie:
They needed to test against some 2011 tropical systems to be sure they didn't break anything and that the gains were real, from what I understand.


They could test it on past seasons though.
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1233. GHOSTY1
alrite guys im goin and be back later till then good bye :)
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Can't help but wonder if the best thing for us in FL would be for Emily to shift her COC eastward and get pulled northward because of her increased strength, get dashed on the mountains. Emily's persistence in heading westward, in defiance of official predictions, is becoming worrisome. I didn't see massive amounts of sheer too close by, and the water should just continue to grow warmer the further west she goes.

If she doesn't die tonight, tomorrow's going to be a VERY interesting day....
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Quoting Mucinex:

LoL! Absolutely!
You don't ever try to change lanes near a Buick with Quebec tags.


LOL!
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Quoting Jedkins01:
there is much more knowledge and wisdom to acquire in my life as I get older, I am only 20, after all.

Berlioz: "Time is a great teacher, but unfortunately kills all its pupils."
Member Since: August 16, 2007 Posts: 6 Comments: 12461
Quoting kmanislander:
If you run this WV loop and check the boxes for the HDW- High winds as well as the box for fronts it gives a good picture of how far South the effects of the trough are now and where the flow diverges between the trough in the N Atl and the high over the CONUS

I dont see the trough catching Emily where it is now and will need to dig a lot further South real soon to do so as Hispaniola is nearly off the image at the bottom.


Kman, just trying to learn how to read the maps. It appears that the low has stopped its progression southward and the area near Bermuda seems to be doing what i think you refer to as a split. Is that correct?
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Quoting stormpetrol:


More models jumping now on the western track
If it takes the southern most models Emily will have a 12 hour plus period to get very strong near cuba beacuse of the high water temps (hotest in the carribian) and very low wind shear.
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Winds are higher than before from the SSW.
Quoting stormpetrol:
Time: 21:15:00Z
Coordinates: 16.5N 69.4833W
Acft. Static Air Press: 842.6 mb (~ 24.88 inHg)
Acft. Geopotential Hgt: 1,563 meters (~ 5,128 feet)
Extrap. Sfc. Press: 1010.0 mb (~ 29.83 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 191° at 29 knots (From the S/SSW at ~ 33.3 mph)
Air Temp: 15.3°C (~ 59.5°F)
Dew Pt: 6.0°C (~ 42.8°F)
Peak (10s) Flt. Lvl. Wind: 35 knots (~ 40.2 mph)
SFMR Peak (10s) Sfc. Wind: 49 knots (~ 56.3 mph)
SFMR Rain Rate: 25 mm/hr (~ 0.98 in/hr)
(*) Denotes suspect data
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I would like to hear from Levi, CCHweather, and Reedzone on their views of the latest updates and their take on the future track of Emily.
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1224. WxLogic
Quoting atmoaggie:
Email says:



Can't wait to see the 18Z HWRF now... :)
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I don't see much change in the forecast. This is one of the times when putting the line in between the dots helps. Basically that line has stayed on one side or the other of New Providence - the little island between Andros and Eleuthera - all day. There's been more change at the bottom end of the cone to accommodate Emily's Wward motion, but other than that, no real change seen.

I am waiting, as, I am sure, the NHC forecasters, to see how the G-IV info impacts the model performance.
Member Since: October 25, 2005 Posts: 19 Comments: 21548
Quoting GetReal:




From that vis loop, Emily has decided she doesn't wanna be a tropical cyclone anymore and wants to be a volcano.

Explains why she doesn't want to go anywhere in a hurry...

...and wanting to be unpredictable.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
How long will we need to give to tell if Emily is going to go north into the weakness or continue westward? The models seem pretty well split on the matter.
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Did the newest cone shift west or east?
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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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