Tropical Storm Henri forms
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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Daily Chuckles in Comments section
It certainly has a superior environment compared to Henri but systems that far S lack the assist from the Coriolis effect to start " spinning ". I know that they can organise even that far S but it takes a lot longer and this wave is already close to SA.
Have to work on dinner now but will be back later.
storm
010L/TS/H
WIDE SHOT DIRECTLY OVERHEAD
Where is Henri's LLC? xD
Quikscat this evening does not show a closed low with Henri IMO but does show 45 knot TS winds.
Should they hold the TS classification ?.
I suspected this might well be the case from all that shear.
XD
looks good but its missing a good LLC
LOL...that's a good one.
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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.
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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.
yep me too
good winds but no LLC
If there is no closed low it is not technically a tropical cyclone. BUT, the NHC maintained Dolly as a TS without a closed low.
Anyway, I did want to see that QS because this reminded so much of those systems that look like a TS on satellite but lack the true qualification to be so classified.
Gone to grill now LOL
maybe if convection persists tonight, tomorrow morning QS could show more of a LLC
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The 00z GFDL run for 91L showed that spinning up briefly. Lowered it to 1008. You can also see on the 00z GFS MSLP that they briefly thought about sending it into the SE Caribbean too. With the way this year has been going and forecasted anything could happen.
Link
well that's true, so its up the NHC for final verdict on whether they will go with continuity or downgrade Henri, I'm leaning towards the former since it may eventually get one.
nope the supposed center is right on the edge of the westernmost area of convection
Seemed everyone on this board wanted to bash the NHC for their actions and look what kind of mess they have to deal with. One hour it's a TD or TS and the next it is an open wave. Weak Systems like these imo shouldn't get a name. I'm with Neil Frank on this one. Guess i'm just old school.
456, wouldn't this new development of LLCless Henri make the forecast track somewhat unreliable since the system hasn't actually consolidated a LLC?
Got 2" of much-needed rain here today (Trinidad). Looks like more to come too, especially from that wave east of here and heading west fast.
Plenty of moist stuff around all of a sudden....
to the east yep but not much to the north =P
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.
Well, if the NHC was to go by "their established Tropical Cyclone rules" this year; they'd have had TS, then TD Danny every other advisory update. Same with Erika.
Excellent point, really reinforces, don't jump on the model wagon so readily. Yes it is likely Henri has been altered by it and probably explain amd's post that is being steered at the levels of tropical waves - more west than wnw. However, i am not a 100% sure that this is open due to the conflict between shortwave imagery and QS.
Yeah Ike did too. Looked like he was headed out to sea. Then he just turned around and went the other way. You're right last year had a lot of people scratching their heads too. Track-wise anyway.
17.9N /54W flat is closest I see to a closed LLC? Does anyone agree?
and the question is where will the center consolidate farther north or farther south?
also the more west than WNW makes sense, I hope it gets its LLC soon so it passes to my NE =)
I would say you're correct, look at my post, we're just 6 miles different, thats well within the margin of error:)
yea that's where I'm seeing the shortwave center
Erika
My mistake...you are correct.
Erika definitely wins in that comparison xD
Click on image to view original size in a new window
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.
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