Tropical Storm Henri forms

By: Dr. Jeff Masters , 9:37 PM GMT on October 06, 2009

Share this Blog
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


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: 407 - 357

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

407. JLPR
Henri and a little interesting TW to the SE

Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting TampaSpin:


The ONLY ONE!....OK


Maybe if I said "Am I the only one?"

That sounds better.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


It seems I'm the only who took time to track and learn from the 8 systems we had. It might not been 2005 but its been a hurricane season regardless, and once there is tropical activity there is always something to learn. And I am sure others here have learn quite alot. the season has been inactive yes but not boring.


The ONLY ONE!....OK
Member Since: Posts: Comments:
I have been following the Tropical Atlantic,for 2009, very closely. Also kept tabs on the E, C, and W PAC storms.
Learned how a mild El Nino can totally wreak havoc on the Tropical ATL.

Wind shear in Severe Weather Country (lived in N TX for 29yrs) creates supercells/tornadic activity. Turning of wind with height in a baroclinic environment is like C4 explosives and you hit the switch! Seen many storms build in 1 hr or less from a cloud to a towering 50,000' super-cell. The super-cell that caused the F4 Lancaster, TX tornado, the cloud height was 73,000'!

In the Tropics, it's like garlic/silver spike to a vampire, it kills them..The E, C and W PAC systems truely benefitted from the low shear/warmer than normal SST there.

There are many people like myself on the blog, who track or watch it all. Weather456, you're a great forecaster and you're not alone!
Member Since: Posts: Comments:
Quoting Weather456:


I will be there for it, so anytime. My 2009 Hurricane Season Forecast Verification is next April after climate data on rainfall, pressure, etc and all post season analysis is already conducted.


I'll be glad to host such a blog forum. We should discuss ideas as to what we should address. I really want to have a good discussion regarding wind shear since it has been such a major player this season and since I still don't have a full understanding regarding the issue.
Member Since: Posts: Comments:

AOI

AOI

AOI

AOI


Daily Chuckles in Comments section
Member Since: October 1, 2007 Posts: 81 Comments: 26512
Quoting atmoaggie:
Of the intensity models, the dynamical models are the ones the NHC clearly is leaning towards...but these dynamical models were not initialized with much of Henri's more recent data. Much more going into the 0 Z models, not due out for a hour or so yet, like sounding data.



Is the LGEM the only dynamical model in the growth area?
Member Since: Posts: Comments:
400. JLPR
I see the center a little farther to the south of the NHC position
near to 17.8 55W
maybe Henri has multiple swirls in a broad area o low pressure?
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting Progster:


24 hr (poor man's ensemble) fcst spread > 30 degrees. Yah, we know where its going :)

Hah. There is a lot of spread just in day one...
Quoting Weather456:


I think how you read it different from how I meant, I know most persons actually learned from the 8 storms we had not just myself. Actually its better understood if said than typed since its in slang form.

Right. Some things have a whole different tone in typed form.
Member Since: Posts: Comments:
Quoting cchsweatherman:


After hurricane season comes to a close, we should hold a blog forum dedicated to trying to understand the various factors that played big roles this hurricane season and analyze their affects on particular systems this year. It would be great to enrich the understanding of future and current forecasters while providing a wealth of knowledge for those who are enthusiasts wanting to learn this field.


I will be there for it, so anytime. My 2009 Hurricane Season Forecast Verification is next April after climate data on rainfall, pressure, etc and all post season analysis is already conducted.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Of the intensity models, the dynamical models are the ones the NHC clearly is leaning towards...but these dynamical models were not initialized with much of Henri's more recent data. Much more going into the 0 Z models, not due out for a hour or so yet, like sounding data.

Member Since: Posts: Comments:
Quoting Weather456:


That is the point I have been trying to make all season. We have already established the season is "dead", call it whatever you want, fine. But instead of reinstating everyday, talk about why and actually contribute to a discussion.

Skypony and I had a long debate over 90L last weekend, and it was very stimulating with valid arguments on both side....then you have those on the side lines "just another naked swirl, season dead, ect, etc"


After hurricane season comes to a close, we should hold a blog forum dedicated to trying to understand the various factors that played big roles this hurricane season and analyze their affects on particular systems this year. It would be great to enrich the understanding of future and current forecasters while providing a wealth of knowledge for those who are enthusiasts wanting to learn this field.
Member Since: Posts: Comments:
Quoting atmoaggie:
BAM statistical suite all stretched out to the west now. And the BAMD doing a little loop-de- (not a whole loop-de-loop).



24 hr (poor man's ensemble) fcst spread > 30 degrees. Yah, we know where its going :)
Member Since: Posts: Comments:
I'm out for the night.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting atmoaggie:

Okay, I know everyone is glad you are here and I think you make a great contribution, but I think you know better.
Humility will earn you almost as much respect as a quality synopsis. Fake it like I do.
;-P


I think how you read it different from how I meant, I know most persons actually learned from the 8 storms we had not just myself. Actually its better understood if said than typed since its in slang form.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
BAM statistical suite all stretched out to the west now. And the BAMD doing a little loop-de- (not a whole loop-de-loop).

Member Since: Posts: Comments:
391. JLPR
Quoting Weather456:
That southern band may clip the northern islands, I have not realize Henri is so close to me.



yeah he is close, and yikes if a band like that passes through here its going to rain, rain hard

im not buying the continued WNW motion, im thinking more of a west movement probably meeting the DR
Member Since: September 4, 2007 Posts: 36 Comments: 5223
After the season, something that really needs closer studying and scrutiny is the fundamentals of wind shear and their true impacts on tropical activity and cyclones. It seems that some systems this year have formed in the face of what seemed to be high wind shear while others struggled with marginally favorable wind shear. There must be other factors associated with wind shear that play a bigger role than we may know.
Member Since: Posts: Comments:
Quoting Weather456:
That southern band may clip the northern islands, I have not realize Henri is so close to me.



*In a whispering voice* i'm closer than you think!
Member Since: Posts: Comments:
I guess that was a little bit of a surprise when they increased intensity at 11. Surprise is my Oct word for the month. Jeff used it on both systems.
Member Since: August 10, 2007 Posts: 0 Comments: 3293
Quoting sporteguy03:


Agreed, not everything is learned in an active season, what about less active seasons? Why are they less active? To me that is interesting as well, I rather hear why it is less active and why these storms struggle then to hear "the blog is dead or season is over" That is why I spend little time on here now.


That is the point I have been trying to make all season. We have already established the season is "dead", call it whatever you want, fine. But instead of reinstating everyday, talk about why and actually contribute to a discussion.

Skypony and I had a long debate over 90L last weekend, and it was very stimulating with valid arguments on both side....then you have those on the side lines "just another naked swirl, season dead, ect, etc"
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


It seems I'm the only who took time to track and learn from the 8 systems we had.

Okay, I know everyone is glad you are here and I think you make a great contribution, but I think you know better.
Humility will earn you almost as much respect as a quality synopsis. Fake it like I do.
;-P
Member Since: Posts: Comments:
Quoting Stormchaser2007:
On the verge of the heavy convection. We'll have to see if a new burst can suck the LLC back under.



there's a mid level vort max to the SSW of Ann-Ree. Its difluent effects will force convection to the S and West of the area of current maximum convection over the next few hours. Short term strengthening is in the cards overnight for sure.
Member Since: Posts: Comments:
That southern band may clip the northern islands, I have not realize Henri is so close to me.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


It seems I'm the only who took time to track and learn from the 8 systems we had. It might not been 2005 but its been a hurricane season regardless, and once there is tropical activity there is always something to learn. And I am sure others here have learn quite alot. the season has been inactive yes but not boring.


Agreed, not everything is learned in an active season, what about less active seasons? Why are they less active? To me that is interesting as well, I rather hear why it is less active and why these storms struggle then to hear "the blog is dead or season is over" That is why I spend little time on here now.
Member Since: Posts: Comments:
382. xcool



update!
Member Since: Posts: Comments:
381. JRRP
bbl
Member Since: August 16, 2007 Posts: 0 Comments: 6209
Henri was embedded in a NW mid-level flow just a few hours ago...changed now.

Mostly just straight west right now.

Member Since: Posts: Comments:
Quoting Weather456:


It seems I'm the only who took time to track and learn from the 8 systems we had. It might not been 2005 but its been a hurricane season regardless, and once there is tropical activity there is always something to learn. And I am sure others here have learn quite alot. the season has been inactive yes but not boring.


You're not the only one man. I've been with you all the way trying to track all these crazy storms this year and understand why forecasts went wrong or try to understand the environmental conditions that caused changes in systems. But, through your analysis and explanations, I have learned more than through my own analysis. Like Chicklit stated, you have been very consistent this season and have never wavered from your approach. Keep up the great work.
Member Since: Posts: Comments:
Quoting Weather456:
This is really just too much, I just like the tropics, nothing more, nothing less. And yea I do work in the field.

I'm not trained or knowledgable enough in the field to say what's what.
.
.

To me, the fact that Dr. Master's made you a feaured blogger, who he recommended in his absence, is good enough for me. Give yourself some credit.
Member Since: Posts: Comments:
Quoting Weather456:


It seems I'm the only who took time to track and learn from the 8 systems we had. It might not been 2005 but its been a hurricane season regardless, and once there is tropical activity there is always something to learn. And I am sure others here have learn quite alot. the season has been inactive yes but not boring.


You do a terrific job with your blogs and posting right or wrong you do put in a lot of work into your material, no one on WU pays you to do this it is greatly appreciated.
Member Since: Posts: Comments:
Quoting Relix:


Steering Layers. You can see the weakness and the weak steering flows, but, you can already see the High building back. If it does before expected it could definitely push the system WSW.
if the sistem survives, do you think
it affect us..(Puerto Rico)
Member Since: Posts: Comments:
375. xcool








Member Since: Posts: Comments:
Quoting ElConando:


There may be stronger westerlies coming in later into the night. Adrian said this earlier, and I believe the NHC believes so too, now if they come is what the question is.
understand, one thing I learned this year is shear forecast seem to be the most unreliable factor. Shear has killed many systems this year. I'm going to watch and see if change in type of shear kills this one to. Are we expecting 30 to 40 Knot shear or just a different form of 20 to 25?
Member Since: August 10, 2007 Posts: 0 Comments: 3293
before you write off this season look at water temps and heat content....so far the high levels of shear have kept them from forming into anything substantial other than Bill. But thats going to relax now...
We could easily have a very active late season..and worse backwards storms like Lenny or Omar of last year..
Member Since: Posts: Comments:
This is really just too much, I just like the tropics, nothing more, nothing less. And yea I do work in the field.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
On the verge of the heavy convection. We'll have to see if a new burst can suck the LLC back under.

Member Since: Posts: Comments:
Quoting Bordonaro:


This year, the NHC did well with Bill. They didn't do well with any other storm.

My $.02 is to watch Henri carefully! Computer models and shear forecasts haven't been real good this season. IF shear decreases, he might ramp up quick.

And the are finally admitting that is moving more to left than previously expected. Plus despise the NHC downcasting odds, the storm continues to improve inprove in organization.
Member Since: Posts: Comments:
369. JRRP
Quoting KoritheMan:


You are forgetting about the unnamed subtropical storm that developed on May 31. So, number wise, we are currently tied with 1997.

is true...
Member Since: August 16, 2007 Posts: 0 Comments: 6209
Quoting Chicklit:

Not kind Sweetie. Honest. You work really hard and study and post and put a lot of thought into this. You should get paid for it!!!
lol.


Doesn't he? Dr. Masters said he worked as a local forecaster.

I agree with you, I really saw it with several systems this year. This season has been difficult for most of us even the NHC, but 456 has nailed several systems on several occasions especially Erika, Grace and this afternoon's Henri. He took heat for it though but came out on top.
Quoting centex:
They only have him surviving TS status until 2AM. They may need to extend that some.


There may be stronger westerlies coming in later into the night. Adrian said this earlier, and I believe the NHC believes so too, now if they come is what the question is.
Member Since: Posts: Comments:
We love you 456...! But we like Drakoen too.
Get used to it. Competition is good.
Anyway, I'm off.
See y'all and thanks for the company.
Regards,
je.
Member Since: July 11, 2006 Posts: 14 Comments: 11407
365. Skyepony (Mod)
I was thinking Grace returned from extratropical death then noticed the cordinates..someone wrote Grace in for Henri.

DATE/TIME LAT LON CLASSIFICATION STORM
06/2345 UTC 17.9N 54.4W T1.5/1.5 GRACE
06/0000 UTC 48.8N 14.3W EXTRATROPICAL GRACE
05/1800 UTC 46.7N 15.5W T2.0/3.0 GRACE
05/1200 UTC 44.3N 17.1W T3.5/3.5 GRACE
Member Since: Posts: Comments:
I second the kudos to weather456.
Apart from Dr. Master's, there's no other blogger that really means more to me.
.
.

When Weather456 speaks...I listen.
Member Since: Posts: Comments:
45mph, this ones another fighter. But will he have enough when conditions become better? The plot thickens!!!
Member Since: Posts: Comments:
Quoting Weather456:


It seems I'm the only who took time to track and learn from the 8 systems we had. It might not been 2005 but its been a hurricane season regardless, and once there is tropical activity there is always something to learn. And I am sure others here have learn quite alot. the season has been inactive yes but not boring.
yes, agree 100 %. AS for me its been a very interesting season. For instance you can say that nothing is written in stones, many expert including Dr. Masters, many of the so call experts here, NHC, and models have failed forecasting. Others have been pretty accurate. Plus another thing that i learn that a moderate "el niño year" can be very tricky for forecasting. Lets see now what we can learn about Henri.
Member Since: Posts: Comments:
They only have him surviving TS status until 2AM. They may need to extend that some.
Member Since: August 10, 2007 Posts: 0 Comments: 3293
Quoting Weather456:


Well thank you for those kind thoughts.

Not kind Sweetie. Honest. You work really hard and study and post and put a lot of thought into this. You should get paid for it!!!
lol.
Member Since: July 11, 2006 Posts: 14 Comments: 11407
Quoting nrtiwlnvragn:
342. cchsweatherman

However SHIPS also shows Henri moving into a dry environment, realtive humidity in the mid twenty percent range after 48 hours.


Don't really see that playing a major role considering the massive, deep moisture field the storm has created over the past few days.
Member Since: Posts: Comments:
358. Relix


Steering Layers. You can see the weakness and the weak steering flows, but, you can already see the High building back. If it does before expected it could definitely push the system WSW.
Member Since: Posts: Comments:
Quoting Chicklit:

Weather456, you deserve a lot of credit and a huge pat on the back for hanging in there. Plus, you had several mentions by Dr. Masters himself! You made it interesting all along the way. I'm not writing the epitaph of the season, especially since Dr. Masters mentioned we could see something in the latter part of October, and in fact we do have two named storms in one week with Grace and Henri...both rather tenuous, but 456 you have really been consistent. This was no easy feat with so little developing. Shear may relax and we may finally see something materialize, but at this point, we'll just have to wait until the end of November. And until then, we do depend on you Weather456 to keep us all on track. So hang in there. You are appreciated.
je


Well thank you for those kind thoughts.
Member Since: July 24, 2005 Posts: 407 Comments: 19076

Viewing: 407 - 357

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

Overcast
56 °F
Overcast