ATL: TROPICAL DEPRESSION HENRI (10L)

[tolakram]

http://www.ssd.noaa.gov/goes/flt/t1/flash-avn.html

Pop, sheared off, pop.

What impresses me is how deep the convection is each burst. There's a lot of energy out there but poor conditions. Hopefully shear will increase again and finish this thing off.

[wxman57]

I don't know that I've ever seen a first advisory as a TS with a forecast for dissipation in 36 hours or less.

TROPICAL STORM GRACE DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092009
1100 PM AST SUN OCT 04 2009

INITIAL 05/0300Z 41.2N 20.3W 55 KT
12HR VT 05/1200Z 44.0N 18.0W 50 KT
24HR VT 06/0000Z 48.0N 16.0W 45 KT
36HR VT 06/1200Z...DISSIPATED

Besides Henri and Grace. What a season.

[ozonepete]

[HURAKAN]

Another burst

[cycloneye]

Here is Dr Jeff Masters interesting discussion about Henri.

Posted by: JeffMasters, 9:37 PM GMT on October 06, 2009

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.

[caribepr]

Well, at this point that seems to be as much sense as we're going to get. Which is WHY we should all be prepared, all of the time, because bottom line, we never know what will happen next.

[cycloneye]

Well, at this point that seems to be as much sense as we're going to get. Which is WHY we should all be prepared, all of the time, because bottom line, we never know what will happen next.

We have to watch 2 things for our area.First,how the storm will track when is around 62-63W as some models want to dip it towards us or to Hispanola.Second is that tail that goes very far south.Even if the center of the system passes to our north,it will depend on how far it passes to get more or less bad weather from the tail.

[jlauderdal]

Here is Dr Jeff Masters interesting discussion about Henri.

Posted by: JeffMasters, 9:37 PM GMT on October 06, 2009

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.

he's covered on the track

[JonathanBelles]

Wow! I left for school this afternoon with a naked swirl and came back to TS Henri. I was certainly surprised. Looks quite good on satellite though. That front is gonna tear it up though.

[caribepr]

Well, at this point that seems to be as much sense as we're going to get. Which is WHY we should all be prepared, all of the time, because bottom line, we never know what will happen next.

We have to watch 2 things for our area.First,how the storm will track when is around 62-63W as some models want to dip it towards us or to Hispanola.Second is that tail that goes very far south.Even if the center of the system passes to our north,it will depend on how far it passes to get more or less bad weather from the tail.

Yes. A friend of mine sailing down island has headed back to the nearest hurricane hole (lucky for him only 7 miles - sailing, that takes awhile) for safe harbour, just in case.

[Emmett_Brown]

Hard to tell without vis, but the convection appears to be holding together in spite of the shear. Some dark tops on IR:

http://www.ssd.noaa.gov/goes/flt/t1/avn-l.jpg

[leanne_uk]

2009, year of the strangest storms

I am loving it.

[Stephanie]

Imagine what kind of season we would've had if it wasn't for the sheer? There's been some tough storms that tried their hardest to survive.

The season isn't over and I don't want to count all of my blessings yet but it seems like Mother Nature has given the Atlantic hurricane region a break this year.

I hope Henri follows the path of all of the others and doesn't adversely affect the Leeward Islands, etc.

[cycloneye]

00 UTC Best Track

AL, 10, 2009100700, , BEST, 0, 181N, 547W, 35, 1007, TS

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 009.invest

[Emmett_Brown]

This upper level wind chart suggests that there is some anticyclonic flow forming over Henri (although Henri is not perfectly situated under it). This is probably why Henri has yet to be completely sheared apart:

[Emmett_Brown]

00 UTC Best Track

AL, 10, 2009100700, , BEST, 0, 181N, 547W, 35, 1007, TS

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 009.invest

Seems to be moving along pretty briskly. Luis, does best track show a forward speed anywhere?

[cycloneye]

00 UTC Best Track

AL, 10, 2009100700, , BEST, 0, 181N, 547W, 35, 1007, TS

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 009.invest

Seems to be moving along pretty briskly. Luis, does best track show a forward speed anywhere?

Waiting for the 00 utc models to see the direction and speed. If my math is right,from 17.8N to 18.1N is three up and 53.4W to 54.7W is 13 to the left.Its moving fast and has not gained much latitud in the past 6 hours.

[cycloneye]

WHXX01 KWBC 070046
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0046 UTC WED OCT 7 2009

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE HENRI (AL102009) 20091007 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
091007 0000 091007 1200 091008 0000 091008 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 18.1N 54.7W 19.2N 57.5W 20.4N 59.8W 21.1N 61.7W
BAMD 18.1N 54.7W 19.3N 56.4W 20.4N 57.9W 21.4N 59.3W
BAMM 18.1N 54.7W 19.2N 56.7W 20.1N 58.4W 20.9N 60.1W
LBAR 18.1N 54.7W 19.6N 56.7W 21.5N 58.2W 23.1N 58.9W
SHIP 35KTS 36KTS 37KTS 37KTS
DSHP 35KTS 36KTS 37KTS 37KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
091009 0000 091010 0000 091011 0000 091012 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 21.6N 63.0W 21.1N 66.2W 20.4N 71.2W 20.7N 77.3W
BAMD 21.9N 60.1W 20.2N 63.3W 18.8N 68.9W 18.7N 74.8W
BAMM 21.3N 61.2W 19.9N 65.4W 18.9N 72.0W 19.0N 78.7W
LBAR 24.5N 57.4W 26.9N 50.0W 28.4N 45.1W 27.7N 38.6W
SHIP 40KTS 45KTS 49KTS 51KTS
DSHP 40KTS 45KTS 49KTS 51KTS

...INITIAL CONDITIONS...
LATCUR = 18.1N LONCUR = 54.7W DIRCUR = 290DEG SPDCUR = 15KT
LATM12 = 16.9N LONM12 = 51.8W DIRM12 = 303DEG SPDM12 = 17KT
LATM24 = 14.9N LONM24 = 48.3W
WNDCUR = 35KT RMAXWD = 45NM WNDM12 = 30KT
CENPRS = 1007MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M
RD34NE = 60NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[caribepr]

Do I tie up the grill again? I hate that!

[Blown Away]

Ships showing slight intensification through 120 hours, for whatever it's worth.