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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Did the newest cone shift west or east?
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1218. GHOSTY1
Quoting stormpetrol:


More models jumping now on the western track


i like the blue track that goes just south of cuba the one thats about the color of the water on the map
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Quoting GetReal:




Looks like if she stays on that heading for much longer tho, she's gonna outrun the cone.
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Apparently the minds of the west-casters are very powerful ;)
Member Since: December 1, 2006 Posts: 2 Comments: 3619
Quoting robj144:


What the heck? They had the whole hurricane "off season" to work on the models and just now they're fixing something... five storms in already. Seems strange to me.
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.
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Quoting stormpetrol:
A GRADUAL TURN TO THE
WEST-NORTHWEST AND NORTHWEST IS EXPECTED DURING THE NEXT DAY OR SO.

Honestly, how many days now? I could be totally wrong, but Emily would have to turn NNW now just to encounter the mountains of Haiti alone.Man has become to dependent on machines, therefore not that he he doesn't have it in him, but common sense and old time forecasting sames to have taken a back seat( just my opinion)



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.
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Have to be careful before deciding its making a more northerly turn, as it is possible that the LLC is getting tugged at by the convection back the the East. Probably one of the reasons she has slowed down. Some pretty deep convection is now firing just to the East of the LLC.

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Quoting MiamiHurricanes09:
Pretty decent convection developing atop Emily's circulation. Evident lower-level outflow boundaries though.

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What everyone can do in these situations is... wait and watch
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Quoting thunderbug91:
That new cone is a joke! I'm sticking with West Palm at 8 AM Sat Morning... or maybe a track to the west coast of FL but definitely not east of West Palm.


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)
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1209. beell
Only a 20 meter height increase (compared to 42 meters) from the start of the last inbound leg (NW to SE) towards the center over the same distance (60nm).



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1208. GetReal


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Looking at TPW--


And sheer tendency-



It would seem if Emily doesn't end up over land tonight, she could definitely find herself more organized.
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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
Member Since: April 29, 2007 Posts: 0 Comments: 7805
Quoting Drakoen:


Good to hear. Should get a solid HWRF 18z run and obviously the others to come.

gonna be real interested to see what it shows tonight around 7:30.
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Quoting atmoaggie:
? Look at the whole history of Emily on that page. It tracks perfectly well, though the min pressure and max wind is admittedly useless.

Our eyeballs aren't as adept at noting a few more or less square miles warmed or cooled in the cloud tops as a well-coded computer algorithm.

The trend in t-numbers in these SSD analyses show the waxing/waning behaviors well before this blog mood changes from RIP to RI to RIP...


Funny how a little P changes a persons mood.
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1203. robj144
Quoting atmoaggie:
Email says:



What the heck? They had the whole hurricane "off season" to work on the models and just now they're fixing something... five storms in already. Seems strange to me.
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1201. Gaea
Quoting spathy:
Spathy is scratching head as well.
The consensus seems to be a track over Haiti and or to its West when Emily does turn more NNW.
Yet the discussions that follow seem to still talking about Emily going over the 10,000' mountains of Hispaniola and getting destroyed.
Even Levi did it during his last tidbit.
The "finger"peninsulas of Haiti dont have that high of mountains do they?



No, blogger Spathy, I did not put very high mountains over the "fingers" of Haiti, assuming you mean the western side. But the little one Emily will still have interaction with the mountains further east- if indeed that is where she chooses to cross- and I did make some of those mountains rather tall.

Quite a favor for you humans in Florida, I must add.
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More models jumping now on the western track
Member Since: April 29, 2007 Posts: 0 Comments: 7805
Quoting Mucinex:

LoL. Actually, yes, both the shutters and the snowbirds are expensive.
But, I'd expect they would be stealing the shutters to sell for scrap, not personal protection.

they use snowbirds for personal protection??!!!? (sorry...couldn't resist)
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Quoting Seflhurricane:
believe it or not we need emily to come over south florida to help wipe out the drought and fill up lake okeechobee


yep. we need it badly. a nice brush up the coast would help NC/SC as well.
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Pretty decent convection developing atop Emily's circulation. Evident lower-level outflow boundaries though.

Member Since: September 2, 2009 Posts: 130 Comments: 21098
Quoting violet312s:


I love WRAL's weather team :) Durham here.
That's cool.
Member Since: August 1, 2011 Posts: 28 Comments: 7961
Just registered for membership, but I have been a lurker for ages. Emily is full of surprises, chugging right along, oblivious to our forecasts, and the models.
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1191. Mucinex
Quoting muddertracker:


Are they expensive? *(The shutters...not the snowbirds)

LoL. Actually, yes, both the shutters and the snowbirds are expensive.
But, I'd expect they would be stealing the shutters to sell for scrap, not personal protection.
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God i feel very frustrated with Emily, it just wont do anything, it wont die as of yet and its has not intensifed (good for hisp). I just want it to do somthing.
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1189. Drakoen

Quoting atmoaggie:
Email says:


Good to hear. Should get a solid HWRF 18z run and obviously the others to come.
Member Since: October 28, 2006 Posts: 57 Comments: 30080
That new cone is a joke! I'm sticking with West Palm at 8 AM Sat Morning... or maybe a track to the west coast of FL but definitely not east of West Palm.
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1187. GHOSTY1
what is the point of the plus 1 button, do you get anything useful out of it or is just to let you know someone agrees with you, imo its worthless, i mean maybe if they gave you a upgrade in the use of site for having a lot of points or something but idk.
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Quoting atmoaggie:
Email says:

So the 18z run that comes out in a few hours has the upgraded model? Perfect.
Member Since: September 2, 2009 Posts: 130 Comments: 21098
Quoting Jedkins01:
Although I was shocked about the track forecast not changing, the new discussion at least shows they are preparing to change the forecast significantly if necessary. They are just playing it safe. If the more westward motion continues overnight into tomorrow and the north turn does not materialize, I expect the official forecast to shift significantly left.
I think they're also waiting for the weakness to close. As long as it's open, they're going to expect Emily to turn into it.
Member Since: October 25, 2005 Posts: 19 Comments: 21864
Quoting GHOSTY1:
i dont think Emily is listening to the NHC they keep telling her to go north but she just won't listen its really sad when you see these storms act this way


well, you know, neither the NHC nor everyone else controls weather or cyclones... they just predict....
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1183. 10Speed
Quoting Stormridr911:
Ok, the NHC acknowledges that Emily is continuing west...already west of their earlier tracks...yet still thinks she is going to suddenly make a hard right turn?? IMO, this is why some people wait so long to start their final preps for a storm. I say swallow the pride and move the tracks west if you can see that it's not following the original track.

I also agree with an earlier post...in that I don't understand why watches weren't issued for part of the ECFL (even if it's south of me...I'm on the Treasure Coast).


Because they have determined that the farther the storm moves west, the greater the northerly turn will be. In other words, they still believe the storm will be staying well east the Florida coast even if it does go further west than originally thought.

That's just my take on it.
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1182. scott39
Emily is moving W or 278 degrees at 15mph. I think its going to cross over Eastern Cuba....if then.
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Email says:

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
2113Z WED AUG 03 2011

A CHANGE TO THE HWRF MODEL SAS DEEP CONVECTION PARAMETERIZATION
SCHEME WAS IMPLEMENTED AS OF THE 18Z WED AUG 3 2011 CYCLE TO
CORRECT AN OUT-OF-BOUND ARRAY PROBLEM AND TO PREVENT RELATED MODEL
FAILURES.

TESTING AND EVALUATION FROM THE 2010 AND 2011 SEASONS SHOWED THIS
CHANGE ALSO RESULTED IN:

1. A LARGE REDUCTION IN NORTHWARD BIAS OFTEN SEEN IN EASTERN
PACIFIC HURRICANE TRACKS.

2. A 35 PERCENT IMPROVEMENT IN HURRICANE TRACK FORECAST ERRORS AND
A 20 PERCENT IMPROVEMENT IN INTENSITY FORECASTS.
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If emily does not make the nw turn by 73W we will have a problem for south florida
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Quoting Bluestorm5:
which meteorologist? I follow WRAL meteorologist and NWS Raleigh (i know their team personally).


I love WRAL's weather team :) Durham here.
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1178. WxLogic
Quoting angiest:


Or trying to find a new COC. Let's see if she jumps backwards at all.


Won't be surprised of a new one if deeper convection develops elsewhere.
Member Since: August 14, 2008 Posts: 4 Comments: 4960
Quoting Mucinex:

They haven't shown the story yet, but alot of people leave their shutters stacked up outside in the yard or in view of open garage doors.
They've been stealing large commercial-size A/C units recently, so, even though, I find it unlikely they took installed shutters off a house, it's certainly not beyond the realm of possibility. Especially, with the snowbirds gone for the season (many put up their shutters before they leave).


Are they expensive? *(The shutters...not the snowbirds)
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Gap is closing:

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1175. ncstorm
Quoting snotly:
Looks like the NAM splits the remnant lows into two voracity centers after Hispaniola


Looking at the 850 vort.


Link

Will there be 2?


a long time ago when emily was being predicted by the models in their intial runs, its was splitting it into two..one taking the east coast and one going into the GOM..
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1174. GHOSTY1
i dont think Emily is listening to the NHC they keep telling her to go north but she just won't listen its really sad when you see these storms act this way
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1173. Mucinex
Quoting muddertracker:

People actually steal hurricane shutters? They unbolt them from houses? That sounds crazy!

They haven't shown the story yet, but alot of people leave their shutters stacked up outside in the yard or in view of open garage doors.
They've been stealing large commercial-size A/C units recently, so, even though, I find it unlikely they took installed shutters off a house, it's certainly not beyond the realm of possibility. Especially, with the snowbirds gone for the season (many put up their shutters before they leave).
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believe it or not we need emily to come over south florida to help wipe out the drought and fill up lake okeechobee
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If Emily makes it to 73W and is not above 18N look for watches , possibly warnings for Jamaica
Member Since: April 29, 2007 Posts: 0 Comments: 7805
Quoting MississippiWx:


That reading will most likely be thrown out then.
You know it, lol. Plenty of pretty decent readings in the southeastern quadrant. All are pretty suspect though.

000
URNT15 KNHC 032120
AF306 0805A EMILY HDOB 30 20110803
211030 1613N 06928W 8427 01561 0100 +150 +056 180030 032 049 014 00
211100 1615N 06928W 8429 01555 0096 +154 +057 181031 033 044 012 00
211130 1617N 06928W 8429 01556 0094 +158 +058 188030 032 038 011 00
211200 1619N 06928W 8432 01553 0097 +153 +059 184033 035 038 009 00
211230 1621N 06928W 8421 01565 0105 +139 +060 172038 039 038 018 03
211300 1623N 06928W 8440 01544 0103 +141 +061 175032 037 048 028 00
211330 1625N 06929W 8419 01566 0100 +145 +061 188029 031 044 031 03
211400 1626N 06929W 8431 01554 0100 +147 +061 182027 030 047 019 03
211430 1628N 06929W 8430 01555 0100 +148 +060 188027 028 040 015 03
211500 1630N 06929W 8426 01563 0100 +153 +060 191029 035 049 025 00
211530 1632N 06929W 8446 01542 0093 +165 +060 178039 040 044 013 03
211600 1634N 06929W 8423 01564 0091 +168 +058 187035 036 032 007 00
211630 1636N 06930W 8432 01558 0097 +163 +057 185035 037 033 007 00
211700 1638N 06930W 8426 01561 0096 +161 +057 184034 035 033 007 00
211730 1640N 06930W 8437 01552 0108 +143 +058 183035 035 034 008 00
211800 1642N 06930W 8425 01563 0092 +166 +058 179034 035 035 005 00
211830 1644N 06930W 8430 01559 0096 +164 +058 176033 034 033 003 00
211900 1646N 06930W 8425 01564 0095 +163 +059 173033 033 034 002 00
211930 1648N 06930W 8426 01564 0094 +166 +060 168035 035 034 001 00
212000 1650N 06931W 8428 01563 0093 +166 +061 165036 037 035 001 00
$$
;
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.

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