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
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 — Blog Index
Is the LGEM the only dynamical model in the growth area?
AOI
AOI
AOI
AOI
Daily Chuckles in Comments section
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.
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!
The ONLY ONE!....OK
Maybe if I said "Am I the only one?"
That sounds better.
LOL.......Bro...its ok.......we know what you ment...YOU keep up your great work. It is really appreaciated a ton on here!
Well, it is a statistical model that uses some dynamical model results as input (mostly GFS?).
Full details here (midway down): http://www.nhc.noaa.gov/modelsummary.shtml
Thanks. I looked it up on the NHC website prior to your post. A hint of history and a bit of thermal forcing from the surface...as good as anything without much of an analysis to go by.
If anyone by chance has had an error message "ERROR: It appears this user does not have a WunderBlog" while you are trying to make a new blog post, I've found a fix (that's what I've been doing for the past half hour). If you have that problem, you can let me know.
By the way, the tropical latitudes in the Atlantic have gotten more interesting. There is a nice 200 mb anticyclone off of Africa and one big one that is coming in from the west over the Gulf of Mexico and western Caribbean. Does anyone understand how that happens? I've just accepted it as "these things just blow in," but I feel there's more to it. How can you look down next week and say, aha there's going to be a favorable 200 mb anticyclone here or there, etc.?
Yeah, me too. Couldn't remember exactly what type that model is.
G'Nite all.
looking good evry hour xcool we may see a 50mph strom at damx up tonight
Link
That sounds like a great idea! I'm all in for that. Sounds like a great learning opportunity!
On another note, Dr. Paul Kocin (from the HPC and formerly from TWC) spoke in a seminar today at Texas A&M today. I made sure to make room for it in my schedule, and boy did that pay off. The seminar was very good and I actually got to talk with him afterwards. I even got a picture with him too! :)
Yeah, that would be exciting to have a forum on that:)! I also keep a journal of Atlantic tropical cyclone activity that I maintain for about about 15 minutes everyday. For this season, I noted some upper atmospheric patterns on a September 15 post I made on my blog (Trends in 2009 Atlantic Hurricane Season). I believe part of it what related to El Nino. But, I am stuck on understanding more shorter term evolutions of the upper atmosphere (how do we get stuck in patterns of aggressive upper troughs one week, and the next we see a nice 200 mb anticyclone in the Gulf of Mexico and western Caribbean like we do today?)
got to agreee with this
Here's one thing I don't quiet get though. How is that REGARDLESS of how the upper atmospheric pattern sets up that there is ALWAYS a Bermuda-Azores surface high producing surface winds in the tropics that are easterly??
This is how I believe Henri is getting sheared, because its embedded in low-level easterlies in the tropics, but the upper winds are westerly.
me too
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm
----- Current Analysis -----
Date : 07 OCT 2009 Time : 024500 UTC
Lat : 18:22:30 N Lon : 55:14:55 W
CI# /Pressure/ Vmax
2.8 /1002.0mb/ 41.0kt
Final T# Adj T# Raw T#
(3hr avg)
2.8 3.0 3.0
Latitude bias adjustment to MSLP : +0.0mb
Center Temp : -28.3C Cloud Region Temp : -29.4C
Scene Type : CURVED BAND with 0.54 ARC in LT GRAY
Positioning Method : FORECAST INTERPOLATION
Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC
Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
maintaining itself
me too xD
Tropical Update with Henri
I was just fixing to ask if I was the only one who thinks it's moving west. Glad its not just me. :)
lol to tell you the truth I have no idea xD
it seemed like it was but the NHC says wnw and they are the experts =)
Yep possibly so......i have it identified above.....It is part of the ITCZ and needs to come out soon to have a chance.
Close.
Big difference between 18.4N/55.3W and 17.2N/54.7W. And, by far the most W winds to date from sat wind data.
Only caught the western edge, but center is S of official, imo. Bedtime. Goodnight.
Link
oh wow!!!!
I give up.. whats the yellow circle for?
Viewing: 401 - 451
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 — Blog Index