Dr. Jeff Masters' WunderBlog

Tropical Storm Henri forms
Posted by: Dr. Jeff Masters, 21:37 GMT le 06 octobre 2009 +3
The tropics spawned another October surprise today, when Tropical Storm Henri formed in the face of adverse levels of wind shear. Henri is under about 20 - 25 knots of wind shear, which ordinarily prevents rapid development like we witnessed this afternoon. However, the environment is quite moist, and Henri is over warm waters, 29°C. An ASCAT pass from 11:37am EDT showed Henri had winds of 40 mph. Satellite loops show that Henri has managed to rapidly develop a large area of intense thunderstorms with cold cloud tops in just a few hours, though the high shear is keeping any thunderstorms from developing on the west side of the center. Water vapor satellite images show that there is some dry air to Henri's northwest, and this dry air will act to slow Henri's growth some. The dry air is creating strong downdrafts that are apparent on visible satellite images as arcs of cumulus clouds spreading out from where the downdraft hits the ocean surface, along the northwest side of Henri's center.

None of the reliable global computer models showed Henri would develop, and the models all favor weakening and dissipation of Henri by Thursday, due to high wind shear of 20 - 25 knots. The official NHC forecast goes along with this scenario, but think there is a medium (30 - 50% chance) that Henri will not dissipate. By Friday, wind shear in the vicinity of Henri (or its remains) is predicted to fall to the low to moderate range. Even if Henri has dissipated by that point, regeneration into a tropical storm may occur. The track of Henri after Friday is problematic, as the storm will be in an area of weak steering currents. Several of the models favor a track to the west-southwest into the Caribbean, across Hispaniola. Residents of the Dominican Republic and Haiti should anticipate that Henri or its remains may bring flooding rains to Hispaniola by Saturday. It is also possible that Henri will get pulled northwards and recurved out to sea, and not affect the Caribbean at all, though.


Figure 1. Latest satellite image of Henri.

A little tropical weather for England
The remnant circulation of Tropical Storm Grace is currently making landfall in Southwest England. Grace's remains brought sustained winds of tropical storm force--41 mph--to one buoy off the coast last hour, and 38 mph to the Sevenstones Lightship buoy. you can track the progress of Grace via our wundermap for the region.


Figure 2. The remnant circulation of Tropical Storm Grace scoots by to the south of Ireland in this visible satellite image taken at 1pm EDT 10/06/09. Image credit: UK Met Office.

Jeff Masters


Categories: Hurricane
  Permalink | A A A
Reader Comments
Display: 0, 50, 100, 200 Sort: Newest First - Order Posted
Viewing: 201 - 251

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14Blog Index

201. WaterWitch11 00:35 GMT le 07 octobre 2009    
Quoting markymark1973:
Just another complete mess like Ana and Danny. I hope it just dies. Weak storms like this are so boring to watch and track.


Not to attack you but I think with each storm something is learned. Grace was not suppose to develop in the cool waters but did. Henri should not have developed due to high wind shear but did. I could go on but it would take a while. I just think that "NOTHING" is text book.
Member Since: 11 août 2008 Posts: 3 Comments: 1266
202. antonio28 00:35 GMT le 07 octobre 2009    
I think tha Henri is relocating the COC that why Dpass doesn't show a close low also the COC of this Storm is a very small one, NHC will keep it as TS in the 11pm advidory maybe at 45mph. I expect a more westward track bringing Henri closer to the NE caribbean.
Member Since: 15 juillet 2008 Posts: 0 Comments: 799
203. Cavin Rawlins 00:35 GMT le 07 octobre 2009    
Quoting JLPR:


Erika definitely wins in that comparison xD


at first glance, yet Erika's LLC was never curved around the LLCC, while Henri's convection is curved around the LLCC. Structurally, Henri winds.
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
204. JLPR 00:35 GMT le 07 octobre 2009    
Quoting nrtiwlnvragn:
Slight indication of an LLC on the EUMETSAT Ocean and Sea Ice SAF Wind Processing Center version of the QuikScat data.


Click on image to view original size in a new window








that confuses me more :|
farther to the south?
Member Since: 4 septembre 2007 Posts: 36 Comments: 5223
205. Cavin Rawlins 00:36 GMT le 07 octobre 2009    
Quoting nrtiwlnvragn:
Slight indication of an LLC on the EUMETSAT Ocean and Sea Ice SAF Wind Processing Center version of the QuikScat data.


Click on image to view original size in a new window








Thanks, can I have a link?
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
206. Cavin Rawlins 00:36 GMT le 07 octobre 2009    
Systems like Erika and Henri are far from boring, due to the uncertain they are more interesting than clear-cut storms like Bill.
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
207. WaterWitch11 00:37 GMT le 07 octobre 2009    
How I learned to mind my own business

I was walking past the mental hospital the other day,
And all the patients were outside shouting, '13...13...13.'

The fence was too high to see over, but I saw a
Little gap in the planks, so I looked through to see
What was going on...

Somebody poked me in the eye with a stick!

Then they all started shouting '14...14...14'...

good evening everyone as always nice to read your posts
Member Since: 11 août 2008 Posts: 3 Comments: 1266
208. Cavin Rawlins 00:37 GMT le 07 octobre 2009    
Quoting JLPR:


that confuses me more :|
farther to the south?


well that image was from a few hours ago, so it lines up perfectly with the center we are currently seeing on shortwave imagery.
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
209. JLPR 00:38 GMT le 07 octobre 2009    
Quoting Weather456:


well that image was from a few hours ago, so it lines up perfectly with the center we are currently seeing on shortwave imagery.


ah nice thanks for that clarification :)
Member Since: 4 septembre 2007 Posts: 36 Comments: 5223
210. stormpetrol 00:39 GMT le 07 octobre 2009    
Quoting Weather456:
Systems like Erika and Henri are far from boring, due to the uncertain they are more interesting than clear-cut storms like Bill.

I agree they add to uncertainity and excitement, also a challenge for forecasters, these are the storms that makes weathermen/women smarter imo.
Member Since: 29 avril 2007 Posts: 0 Comments: 6399
211. nrtiwlnvragn 00:40 GMT le 07 octobre 2009    
Quoting CosmicEvents:

LOL...that's a good one.
.
.
I only brought up the whole pronunciation thing because the NHC started it. Today was the first time that I recall the NHC giving out proper pronunciation in a discussion.
.
.
For years, we somehow got by without the pronunciation leson, and we also managed to get by without the "idiot" colors. For most, they never get past just looking at the NHC graphical map. They don't read the discussions. So they don't understand the reasoning behind the colors. Even those of us here, who go way beyond just reading the discussion, for most, I don't think that they understand the 24-48 hour probability window that these idiot colors represent.


NHC has in the past included pronunication in the forecast discussion. They also have a webpage on pronounciation.
Member Since: 23 septembre 2005 Posts: 11 Comments: 8932
212. homelesswanderer 00:40 GMT le 07 octobre 2009    
Quoting WaterWitch11:
How I learned to mind my own business

I was walking past the mental hospital the other day,
And all the patients were outside shouting, '13...13...13.'

The fence was too high to see over, but I saw a
Little gap in the planks, so I looked through to see
What was going on...

Somebody poked me in the eye with a stick!

Then they all started shouting '14...14...14'...

good evening everyone as always nice to read your posts


Lol. Good evening. :)
Member Since: 15 août 2008 Posts: 10 Comments: 3665
213. centex 00:40 GMT le 07 octobre 2009    
October looking to be the surprise month.
Member Since: 10 août 2007 Posts: 0 Comments: 2856
214. nrtiwlnvragn 00:42 GMT le 07 octobre 2009    
Quoting Weather456:


Thanks, can I have a link?


Link

Select on the right hand side.
Member Since: 23 septembre 2005 Posts: 11 Comments: 8932
215. Cavin Rawlins 00:42 GMT le 07 octobre 2009    
Quoting stormpetrol:

I agree they add to uncertainity and excitement, also a challenge for forecasters, these are the storms that makes weathermen/women smarter imo.


well said, you learn and open yourself to multiple possibilities.
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
216. xcool 00:43 GMT le 07 octobre 2009    


Member Since: 26 septembre 2009 Posts: 2 Comments: 15503
217. CybrTeddy 00:43 GMT le 07 octobre 2009    
Dolly lost its LLC while relocating when it was just going over the Yucatan if any of you remember. They'll keep it a TS at 11.

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM DOLLY DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042008
1100 PM EDT SUN JUL 20 2008

DATA FROM A NOAA P3 AIRCRAFT INDICATE THAT DOLLY HAS NOT BECOME ANY
BETTER ORGANIZED THIS EVENING. INDEED...THE SYSTEM PROBABLY
DOESN'T HAVE A CLOSED SURFACE CENTER RIGHT NOW.
HOWEVER...DOLLY IS
MAINTAINING VIGOROUS CONVECTION AND THE STRONGEST WINDS...AS
ESTIMATED BY THE SFMR...HAVE INCREASED TO 45 KT. SINCE DOLLY COULD
REGENERATE A CENTER AT ANY TIME...NO GOOD WOULD BE SERVED BY
HANGING ON A TECHNICALITY
.

Member Since: 8 juillet 2005 Posts: 253 Comments: 20248
218. Cavin Rawlins 00:44 GMT le 07 octobre 2009    
I wonder why the two QS versions differ considering it is basically the same pass.
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
219. JLPR 00:44 GMT le 07 octobre 2009    
if this: Link

equals this: Link

why do I see a LLC on one and not on the other :|
Member Since: 4 septembre 2007 Posts: 36 Comments: 5223
220. JLPR 00:45 GMT le 07 octobre 2009    
Quoting Weather456:
I wonder why the two QS versions differ considering it is basically the same pass.


i said the same thing =P
Member Since: 4 septembre 2007 Posts: 36 Comments: 5223
221. tropics21 00:46 GMT le 07 octobre 2009    
Quoting Weather456:


This was an image of 91L earlier today and met the criteria and thus was named. Whether or not it lost its LLC and became an open wave has nothing to do with earlier this afternoon.



IMO I think there needs to be a specific period of time that the established LLC has to sustain before a tropical storm is named heck the way they are off again On again they could run out of names in a given year with 12 hour cyclones But that's just my opinion
Member Since: 23 août 2008 Posts: 0 Comments: 263
222. Cavin Rawlins 00:48 GMT le 07 octobre 2009    
Quoting tropics21:
IMO I think there needs to be a specific period of time that the established LLC has to sustain before a tropical storm is named heck the way they are off again On again they could run out of names in a given year with 12 hour cyclones But that's just my opinion


I think Henri LLC has been forming since 5 am this morning, just after we began receiving GOES-12 images from the eclipse.
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
223. lakeEFX 00:48 GMT le 07 octobre 2009    
Quoting Weather456:
Systems like Erika and Henri are far from boring, due to the uncertain they are more interesting than clear-cut storms like Bill.

I agree. Goes to show you, even Mother Nature can "think outside the box."
Member Since: 29 Mars 2008 Posts: 0 Comments: 114
224. centex 00:49 GMT le 07 octobre 2009    
For some reason October means, develop in hostile environment. Either develops in cold water and now with high shear very Interesting.
Member Since: 10 août 2007 Posts: 0 Comments: 2856
225. CandiBarr 00:49 GMT le 07 octobre 2009    
Quoting Weather456:
I wonder why the two QS versions differ considering it is basically the same pass.


most likely becuase its two different organizations reading, organizating, displaying the data.

it could be a simple as the difference between the programming code, graphics resolution etc.
226. nrtiwlnvragn 00:49 GMT le 07 octobre 2009    
Quoting Weather456:
I wonder why the two QS versions differ considering it is basically the same pass.


EUMETSAT must use a slightly different automatic algorithm for wind solutions.

From The Operational Use of QuikSCAT Ocean Surface Vector Winds at the
National Hurricane Center


The design of the QuikSCAT instrument results in up
to four possible wind solutions, or ‘‘ambiguities,’’ in
each wind vector cell (WVC) over which the retrieval
is performed. An ambiguity removal filter chooses a
solution (hereafter the ‘‘automated’’ solution) from
among the ambiguities in each WVC (Hoffman and
Leidner 2005). The ambiguity removal filter utilized in
the NESDIS NRT retrievals is initialized with a 6–9-h
forecast 10-m wind field from the NCEP Global Forecast
System (GFS) model. Both the automated solutions
and the ambiguities are displayable in N-AWIPS at
NHC, which is important since the ambiguities are often
manually analyzed by a forecaster to properly interpret
the QuikSCAT retrievals, especially in TCs.


Tropical cyclone center locations derived from the
automated QuikSCAT wind solutions are often unreliable,
showing large positional errors or the absence of a
closed circulation altogether. Therefore, forecasters at
NHC perform a manual analysis of all the possible wind
solutions (i.e., an ‘‘ambiguity analysis’’) in an attempt to
locate the surface circulation or determine if one exists.
This manual procedure is essentially a streamline
analysis that is performed by examining all of the possible
ambiguities, working inward toward a suspected
center and attempting to choose ambiguities that correspond
to a closed cyclonic circulation.1 The starting
point for the analysis is chosen, if possible, in a region
where either the wind direction is known from other
observations, or at points in the QuikSCAT swath that
show only two or three potential wind directions (i.e.,
two- or three-way ambiguities), implying less uncertainty
in the wind direction
Member Since: 23 septembre 2005 Posts: 11 Comments: 8932
227. Bordonaro 00:50 GMT le 07 octobre 2009    
Quoting nrtiwlnvragn:


NHC has in the past included pronunication in the forecast discussion. They also have a webpage on pronounciation.


Henri is "AHN ree"! Earlier, I called Henri a "she" earlier and mispronounced his name! And I am "Smarter than a 5TH grader"!

TS Henri is still firing off plenty of deep convection.
Member Since: 25 août 2009 Posts: 20 Comments: 6785
228. WaterWitch11 00:50 GMT le 07 octobre 2009    
Is it possible for these 2 storms to merge? Anyone?
Member Since: 11 août 2008 Posts: 3 Comments: 1266
229. homelesswanderer 00:50 GMT le 07 octobre 2009    
What this means, other than a fleeting at best cold front, is that this trough anyway may not make it far south enough to have any affect on Henri. Of course this is the NW GOM. The trough may swing deeper off the east coast, I don't know.

GFS SUGGEST FRONT ONLY GETS INTO NORTHERN GULF THEN
STALLS...AS HAS BEEN THE CASE SO FAR THIS FRONTAL SEASON. THE
ECMWF IS MORE AGGRESSIVE IN BRINGING THE FRONT CLEANLY THROUGH THE
COASTAL WATERS WITH CONTINTENTAL INFLUENCES OF DRIER AND COOLER
AIR. GIVEN STRENGTH OF SURFACE HIGH...THIS FRONT SHOULD HAVE MORE
INTEGRITY THAN PREVIOUS FRONTS CLOSER TO ECMWF SOLUTION. HIGH
PRESSURE THEN BUILDS AND MOVES EAST IN TIME SATURDAY THROUGH
MONDAY.

&&

.MARINE...
LIGHT ONSHORE FLOW TONIGHT AND MUCH OF WEDNESDAY WILL INCREASE TO
MODERATE LEVELS THURSDAY IN ADVANCE OF THE COLD FRONT. A WIND
SHIFT TO NORTHEAST DOES TAKE PLACE FRIDAY WITH FRONTAL PASSAGE BUT
AIR MASS WILL BE LOSING INTEGRITY IN THE PROCESS...WHICH SHOULD
BRING EAST TO SOUTHEAST WINDS BACK THROUGH THE COASTAL WATERS
SATURDAY AND SUNDAY. ONSHORE FLOW SHOULD THEN PREVAIL AT LIGHT TO
MODERATE LEVELS MONDAY THROUGH WEDNESDAY.
Member Since: 15 août 2008 Posts: 10 Comments: 3665
230. tropics21 00:54 GMT le 07 octobre 2009    
Quoting Weather456:


I think Henri LLC has been forming since 5 am this morning, just after we began receiving GOES-12 images from the eclipse.
Thanks weather456
Member Since: 23 août 2008 Posts: 0 Comments: 263
232. tornadofan 00:56 GMT le 07 octobre 2009    
For those familiar with the NFL or NCAA football, when using instant replay, the video has to show irrefutable evidence to reverse the call on the field. Similarly, I believe the NHC will have to see irrefutable evidence before stating Henri has lost it's LLC.
Member Since: 5 avril 2007 Posts: 83 Comments: 12345
233. nrtiwlnvragn 00:56 GMT le 07 octobre 2009    
AL 10 2009100700 BEST 0 181N 547W 35 1007 TS
Member Since: 23 septembre 2005 Posts: 11 Comments: 8932
235. GeoffreyWPB 00:57 GMT le 07 octobre 2009    
06/2345 UTC 17.9N 54.4W T1.5/1.5 HENRI -- Atlantic
Member Since: 10 septembre 2007 Posts: 0 Comments: 9124
236. Cavin Rawlins 00:58 GMT le 07 octobre 2009    
Quoting nrtiwlnvragn:
AL 10 2009100700 BEST 0 181N 547W 35 1007 TS



this confirms it GeoffreyWPB and stormpetrol

That's the infrared center
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
237. GeoffreyWPB 00:58 GMT le 07 octobre 2009    
Quoting StSimonsIslandGAGuy:
The storm Ruth merged with was Pat.


Sounds like a skit on SNL..:)
Member Since: 10 septembre 2007 Posts: 0 Comments: 9124
238. homelesswanderer 00:59 GMT le 07 octobre 2009    
Quoting tornadofan:
For those familiar with the NFL or NCAA football, when using instant replay, the video has to show irrefutable evidence to reverse the call on the field. Similarly, I believe the NHC will have to see irrefutable evidence before stating Henri has lost it's LLC.


Ah I see. Nice analogy.
Member Since: 15 août 2008 Posts: 10 Comments: 3665
240. Bordonaro 01:00 GMT le 07 octobre 2009    
Quoting lakeEFX:

I agree. Goes to show you, even Mother Nature can "think outside the box."

Atmospheric dynamics do NOT always "color between the lines"!

In math 1 + 1 always equals 2. The atmospheric dynamics may be similar but are never, ever the same. So many variables, not even a computer can accurately assess and predict an outcome.

That's why I love weather :0)!
Member Since: 25 août 2009 Posts: 20 Comments: 6785
241. Bordonaro 01:03 GMT le 07 octobre 2009    
Quoting GeoffreyWPB:


Sounds like a skit on SNL..:)


I remember that SNL skit, "Pat"! Ha, ha, ha :0).

Member Since: 25 août 2009 Posts: 20 Comments: 6785
242. Drakoen 01:06 GMT le 07 octobre 2009    
The SHIPS analyzes shear at 25 knots over the system. Conditions, according to the SHIPS, should remain unfavorable for significant development over the 24 hours before upper level winds and directional shear become more conducive. Assuming the system lasts that long, it may organize further before running into the Greater Antilles.
Member Since: 28 octobre 2006 Posts: 57 Comments: 29010
243. homelesswanderer 01:07 GMT le 07 octobre 2009    
Quoting Bordonaro:


I remember that SNL skit, "Pat"! Ha, ha, ha :0).



And her/his? date Chris. Lol.
Member Since: 15 août 2008 Posts: 10 Comments: 3665
244. WxLogic 01:08 GMT le 07 octobre 2009    
Guys don't forget QS is starting to die little by little. I believe atmogie posted some info on it a while back so... it sure looking like NHC and/or other organization(s) are starting to look into ASCAT instead of QS as the Euro version is more reliable... IMO.
Member Since: 14 août 2008 Posts: 4 Comments: 4667
245. hurricanexo 01:09 GMT le 07 octobre 2009    
just catching up.

waterwitch that was a great one. thanks for the entertainment.
246. nrtiwlnvragn 01:11 GMT le 07 octobre 2009    
Quoting Drakoen:
The SHIPS analyzes shear at 25 knots over the system. Conditions, according to the SHIPS, should remain unfavorable for significant development over the 24 hours before upper level winds and directional shear become more conducive. Assuming the system lasts that long, it may organize further before running into the Greater Antilles.


Also NHC may not dissipate the storm as quickly since the track used on the latest SHIPS is the interpolated official forecast, which shows it going out to 96 hours.
Member Since: 23 septembre 2005 Posts: 11 Comments: 8932
247. ElConando 01:13 GMT le 07 octobre 2009    
Quoting Drakoen:
The SHIPS analyzes shear at 25 knots over the system. Conditions, according to the SHIPS, should remain unfavorable for significant development over the 24 hours before upper level winds and directional shear become more conducive. Assuming the system lasts that long, it may organize further before running into the Greater Antilles.


It could miss Haiti, which would definitly boost its chances.
Member Since: 6 septembre 2009 Posts: 2 Comments: 3703
248. Cavin Rawlins 01:14 GMT le 07 octobre 2009    
Quoting WxLogic:
Guys don't forget QS is starting to die little by little. I believe atmogie posted some info on it a while back so... it sure looking like NHC and/or other organization(s) are starting to look into ASCAT instead of QS as the Euro version is more reliable... IMO.


I did not had QS in 1998 and I did not know to use it until 2001, we have to go back to old fashion forecasting. It might be a bit more difficult but ASCAT has a narrower swath and the same time lapse as QS, which is a downgrade. Tonight is a perfect example. We were able to get a center without using QS and it verified per the 0000UTC, so this is what we might be in for, so start learning (not in a rude way though).
Member Since: 24 juillet 2005 Posts: 407 Comments: 19076
249. xcool 01:14 GMT le 07 octobre 2009    



Member Since: 26 septembre 2009 Posts: 2 Comments: 15503
251. Drakoen 01:17 GMT le 07 octobre 2009    
What the NHC is looking at to dissipate the storm is that large trough to northwest of Henri. As that trough advects eastward, shear will increase over the next 24 hours.
Member Since: 28 octobre 2006 Posts: 57 Comments: 29010

Viewing: 201 - 251

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14Blog Index

New Comment
Community Standards Policy Comments will take a few seconds to appear.
Post Your Comments
Please sign in to post comments.
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.
About JeffMasters
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 Rain
66 ° F
Pluie fine
Community Activity