Tropical Storm Henri forms

By: Dr. Jeff Masters , 21:37 GMT le 06 octobre 2009

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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


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657. newenglandnative
14:18 GMT le 07 octobre 2009
As quickly as Henri came to life he may just as quickly fizzle out. NHC is definitely of that opinion due to the immediate adverse environment he'll have to get through today.
Member Since: 24 septembre 2005 Posts: 0 Comments: 118
656. stoormfury
13:50 GMT le 07 octobre 2009
I said in an earlier post .should this new disturbance get into the caribbean, then it will be talk of the 2009 hurricane season
Member Since: 22 août 2006 Posts: 0 Comments: 2720
655. antonio28
13:38 GMT le 07 octobre 2009
Quoting amd:


that would be me. And, yes, since it is embedded within the low-level flow (because pressures with Henri are still relatively high), it will continue to move west.

Also, for those who say don't follow the convection, the shear for Henri is supposed to be out of the sw to ne, however convection is building to the sw. This means two possible things:

1) Shear may be beginning to lessen
2) Henri is trying to move south of due west.

These two things need to be watched closely over the next few hours.

Have to leave for work, everyone have a good day.


I am home sick so I will be entretain by Henri and the NHC folks, they will have it right in the next advisory is too close to land.
Member Since: 15 juillet 2008 Posts: 0 Comments: 799
653. IKE
13:35 GMT le 07 octobre 2009
NEW BLOG!!!
Member Since: 9 juin 2005 Posts: 23 Comments: 37860
652. homelesswanderer
13:35 GMT le 07 octobre 2009
new blog
Member Since: 15 août 2008 Posts: 10 Comments: 3665
651. AwakeInMaryland
13:35 GMT le 07 octobre 2009
644.
Oh, that's easy, that would be the color of your aura.
I've made a promise to myself never to be mean-spirited on this blog; it's a learning and information tool -- so I'm out now, nothing I need to "win" here. Have a nice day, seriously.
Member Since: 19 août 2008 Posts: 32 Comments: 1918
650. Squid28
13:31 GMT le 07 octobre 2009
Quoting StormW:
Where's all the "seasons over" folks?


Maybe they are at the Sams Club or Costco looking for a deal on bulk crow, A1 and maybe a little wsweet and sour sauce....
Member Since: 23 mai 2006 Posts: 0 Comments: 343
649. Orcasystems
13:29 GMT le 07 octobre 2009
Quoting JF939410:
RE: 642

Kissy. kissy, kissy...

I am thinking of the color "brown..."


Thats not only uncalled for, your also wrong.
StormW is a Met.. and when the situation warrants it, he can be quite humorous. He does not do it on here very often.. but when he does its a good one.
Member Since: 1 octobre 2007 Posts: 81 Comments: 26511
648. ackee
13:28 GMT le 07 octobre 2009
does any model devlop pre92L it looks going into SA no surface low either not convince
Member Since: 15 juillet 2008 Posts: 0 Comments: 1376
647. weathermanwannabe
13:28 GMT le 07 octobre 2009
Good Morning. Having trouble interpreting the current CIMSS shear chart. Looks like Henri is slipping west of the noted band of 30-40 knots and the next noted band of 20 knots is to it's W/NW at around 20N/60W with Henri in the middle right now between the two. Anyone have a guess at what the sheer over Henri is right now (during the course of today) or do I just assume anywhere between 20-30 knots for the time being?

Thanks.
Member Since: 8 août 2006 Posts: 0 Comments: 9330
646. FLWeatherFreak91
13:28 GMT le 07 octobre 2009
Quoting PensacolaDoug:
It's also about time for the "its gonna destroy Florida" contingent to show up!
That's going to happen if any model decides to randomly select Florida. Until then, the blog can proceed in peace.
Member Since: 1 décembre 2006 Posts: 2 Comments: 3631
643. TampaSpin
13:26 GMT le 07 octobre 2009


TampaSpins Tropical update
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
642. AwakeInMaryland
13:23 GMT le 07 octobre 2009
Re 636.
He's both; has intelligence AND wit. Take a clue.

G'morning, StormW, really looking forward to your update...coming soon?
Member Since: 19 août 2008 Posts: 32 Comments: 1918
641. PanhandleChuck
13:22 GMT le 07 octobre 2009
Quoting PensacolaDoug:
It's also about time for the "its gonna destroy Florida" contingent to show up!


Yes sir Doug.... Cat 8 with 450 mph winds and a 76 foot storm surge. (incase you didn't know, that was a j/k LOL)
Member Since: 13 mai 2008 Posts: 0 Comments: 1414
640. homelesswanderer
13:21 GMT le 07 octobre 2009
Quoting OSUWXGUY:
Convectiong waning a bit near the center...allowing it to become exposed again...



Yep. Just goes to show how some satellite shots are deceiving. I thought it was at 18n that clearly looks like 19n. And moving just north of west. Thanks for posting that.
Member Since: 15 août 2008 Posts: 10 Comments: 3665
639. PensacolaDoug
13:20 GMT le 07 octobre 2009
It's also about time for the "its gonna destroy Florida" contingent to show up!
Member Since: 25 juillet 2006 Posts: 0 Comments: 591
635. TampaSpin
13:16 GMT le 07 octobre 2009
They are in the Daily Chuckles section! That's where they belong.......LOL
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
634. OSUWXGUY
13:15 GMT le 07 octobre 2009
Convectiong waning a bit near the center...allowing it to become exposed again...

633. superpete
13:15 GMT le 07 octobre 2009
Quoting StormW:
Where's all the "seasons over" folks?
They have gone real quiet this morning(good morning to you)
Member Since: 10 octobre 2007 Posts: 0 Comments: 708
632. Orcasystems
13:13 GMT le 07 octobre 2009

AOI

AOI

AOI

AOI


Daily Chuckles in Comments section


MELOR
Forecast Storm Position
Oct 7 - 18:00 UTC
Typhoon
Maximum winds of 075 knots
Gusts to 090 knots
Latitude: 33.6
Longitude: 135.5
Member Since: 1 octobre 2007 Posts: 81 Comments: 26511
631. TampaSpin
13:12 GMT le 07 octobre 2009
Quoting kmanislander:


LOL

Seriously though, I hope nothing makes it to the NW Caribbean. Cat 5 if it does.


ON a very serious note your correct if its under low shear....the Heat Content there is unreal and deep depths.
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
630. CUBWF
13:10 GMT le 07 octobre 2009
Quoting GeoffreyWPB:
07/1145 UTC 18.7N 56.4W T2.5/2.5 HENRI -- Atlantic

I think I was close. lol
629. TampaSpin
13:10 GMT le 07 octobre 2009
if you look at post 612 the BAM models just switched South again.......heck 10minutes ago they stayed over water into the Bahamas! Models are going to bounce around a bit more with this as it nearly stalls.
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
628. OSUWXGUY
13:09 GMT le 07 octobre 2009
Interesting to look at all the pieces to Henri's future...

SHIPS shows weakening westerly shear swinging around to the north and then to the northeast...which would be a postive for strengthening.

However, the 200mb divergence goes from being favorable (+) now to negative (convergence) in 12 hours which should reduce convection.

Also, the 850 environmental vorticity becomes VERY unfavorable as anti-cyclonic flow around the ridge centered over Florida builds in.

12UTC SHIPS FORECAST
627. GeoffreyWPB
13:09 GMT le 07 octobre 2009
07/1145 UTC 18.7N 56.4W T2.5/2.5 HENRI -- Atlantic
Member Since: 10 septembre 2007 Posts: 0 Comments: 11432
626. kmanislander
13:09 GMT le 07 octobre 2009
Quoting TampaSpin:


Out trying to sell some!


LOL

Seriously though, I hope nothing makes it to the NW Caribbean. Cat 5 if it does.
Member Since: 19 août 2006 Posts: 0 Comments: 15882
625. TampaSpin
13:07 GMT le 07 octobre 2009
Quoting kmanislander:


Putting up shutters !


Out trying to sell some!
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
624. homelesswanderer
13:07 GMT le 07 octobre 2009
MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
330 AM EDT WED OCT 07 2009

CARIBBEAN AND TROPICAL N ATLC...
TROPICAL STORM HENRI AT 18.4N 55.3W AT 0300 UTC WITH WINDS OF 40
KT WITHIN GUSTS TO 50 KT IS FORECAST TO WEAKEN TO A MINIMAL
TROPICAL STORM NEAR 18.4N 55.3W WED MORNING AND WEAKEN FURTHER
TO A 30 KT DEPRESSION BY 20.5N59/7W WED NIGHT BEFORE DIMINISHING
TO A REMNANT LOW NEAR 21.8N 61.9W THU MORNING AS A HIGHLY
AMPLIFIED NORTHERN STREAM TROUGH SWEEPS THROUGH THE CENTRAL N
ATLC. WINDS AND SEAS ASSOCIATED WITH HENRI SHOULD DIMINISH BELOW
20 KT/8 FT CRITERIA OVER THE TROPICAL N ATLC ZONE AROUND MID-DAY
THU.

I'm thinking this might be a little off. :)
Member Since: 15 août 2008 Posts: 10 Comments: 3665
623. CaicosRetiredSailor
13:07 GMT le 07 octobre 2009
Quoting StormW:
Where's all the "seasons over" folks?


passed out behind the "Taco" stand...

heh heh
Member Since: 12 juillet 2007 Posts: 0 Comments: 6065
622. TampaSpin
13:07 GMT le 07 octobre 2009
Quoting kmanislander:


Putting up shutters !


LMAO
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
621. CUBWF
13:06 GMT le 07 octobre 2009
Good Morning everyone. The center appear to be exposed again moving a more to the wnw. 18.8 and 56.7. Some dry air to the nw could be another problem for Henri to deal with.
620. kmanislander
13:06 GMT le 07 octobre 2009
Quoting StormW:
Where's all the "seasons over" folks?


Putting up shutters !
Member Since: 19 août 2006 Posts: 0 Comments: 15882
619. TampaSpin
13:06 GMT le 07 octobre 2009
Quoting StormW:
Where's all the "seasons over" folks?


Up in Canada where its turning cold....lol
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
617. homelesswanderer
13:04 GMT le 07 octobre 2009
Quoting StormW:
Good morning!


Good Morning Storm. :)
Member Since: 15 août 2008 Posts: 10 Comments: 3665
616. kmanislander
13:03 GMT le 07 octobre 2009
Quoting amd:


that would be me. And, yes, since it is embedded within the low-level flow (because pressures with Henri are still relatively high), it will continue to move west.

Also, for those who say don't follow the convection, the shear for Henri is supposed to be out of the sw to ne, however convection is building to the sw. This means two possible things:

1) Shear may be beginning to lessen
2) Henri is trying to move south of due west.

These two things need to be watched closely over the next few hours.

Have to leave for work, everyone have a good day.


See my post 594. Shear has been falling quickly
Member Since: 19 août 2006 Posts: 0 Comments: 15882
613. amd
12:53 GMT le 07 octobre 2009
Quoting antonio28:
Henri is moving Westward as a pointed out by me and other blogger yesterday night. Advisories should be issue at 11am for the nothermost Leeward island it is not going north anytime soon, NHC compleatly miss this one. Remember when the post it the red alert "Henri will pass Far north of the noethen island" when I read that only one exprecion came to my mind was LOL! They are smoking good stuff.


that would be me. And, yes, since it is embedded within the low-level flow (because pressures with Henri are still relatively high), it will continue to move west.

Also, for those who say don't follow the convection, the shear for Henri is supposed to be out of the sw to ne, however convection is building to the sw. This means two possible things:

1) Shear may be beginning to lessen
2) Henri is trying to move south of due west.

These two things need to be watched closely over the next few hours.

Have to leave for work, everyone have a good day.
Member Since: 29 août 2005 Posts: 0 Comments: 1024
612. TampaSpin
12:51 GMT le 07 octobre 2009
BAM models
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448
611. ElConando
12:51 GMT le 07 octobre 2009
Henri too a jog to the SW last night but had resumed a generally Western motion with a little northern component. Too small infact to be considered WNW thus W is the call.
Member Since: 6 septembre 2009 Posts: 2 Comments: 3779
610. IKE
12:48 GMT le 07 octobre 2009
My hometown....

WZEP AM 1460 DeFuniak Springs, FL, DeFuniak Springs, Florida (PWS)
Updated: 0 sec ago
Clear
76.1 °F
Clear
Humidity: 100%
Dew Point: 76 °F

Wind: 0.0 mph
Wind Gust: 0.0 mph
Pressure: 30.01 in (Steady)
Heat Index: 75 °F
Visibility: 3.0 miles
UV: 0 out of 16
Clouds:
Clear -
(Above Ground Level)
Elevation: 174 ft
Member Since: 9 juin 2005 Posts: 23 Comments: 37860
609. CandiBarr
12:47 GMT le 07 octobre 2009
Quoting IKE:
Henri appears to be moving just north of west.


KK, must just be the appearance the deep convention is giving me. b/c my eyes see due west, my brain see's somethin else. LOL
608. antonio28
12:46 GMT le 07 octobre 2009
Henri is moving Westward as a pointed out by me and other blogger yesterday night. Advisories should be issue at 11am for the nothermost Leeward island it is not going north anytime soon, NHC compleatly miss this one. Remember when the post it the red alert "Henri will pass Far north of the noethen island" when I read that only one exprecion came to my mind was LOL! They are smoking good stuff.
Member Since: 15 juillet 2008 Posts: 0 Comments: 799
607. TampaSpin
12:46 GMT le 07 octobre 2009
Member Since: 2 septembre 2007 Posts: 179 Comments: 20448

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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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