Tropical Storm Helene,Analysis,Sat Pics,Models Thread #3

[Meso]

Thread #2

[chadtm80]

Helene 48-hour loop:



And would someone please be so kind as to re-post this in the new thread that will start shortly after I post this?

[storms in NC]

Looking at the wvloop of all you can see that Gordon has a pull on Helene. That is why she is going NNW Imo

http://www.ssd.noaa.gov/goes/east/nwatl/loop-wv.html

[Nimbus]

And here is a quick loading single frame image of all the players.

http://www.ssd.noaa.gov/goes/east/natl/wv-l.jpg

Just noticed the new westward motion starting.. Gordon and the little low that was to the north of Helene are pulling out. If Helene goes cat 4 she may pump up the ridge more than the models predicted. Usually troughs dig and recurve hurricanes but the flow has been almost zonal over Gordon the last few days.

Actually its the strength and geometry of the ridge that causes troughs to detour like that. The GFS assumed a weaker ridge developing which seems a little strange considering the circumstances? Any pro mets have the explanation for that?

[Thunder44]

Did anybody see the last two GFDL runs for Gordon? Look what it does to Helene:

http://moe.met.fsu.edu/tcgengifs/

[gatorcane]

And here is a quick loading single frame image of all the players.

http://www.ssd.noaa.gov/goes/east/natl/wv-l.jpg

Just noticed the new westward motion starting.. Gordon and the little low that was to the north of Helene are pulling out. If Helene goes cat 4 she may pump up the ridge more than the models predicted. Usually troughs dig and recurve hurricanes but the flow has been almost zonal over Gordon the last few days.

Actually its the strength and geometry of the ridge that causes troughs to detour like that. The GFS assumed a weaker ridge developing which seems a little strange considering the circumstances? Any pro mets have the explanation for that?

What does "pump up the ridge mean?"

[gatorcane]

Did anybody see the last two GFDL runs for Gordon? Look what it does to Helene:

http://moe.met.fsu.edu/tcgengifs/

I can't see it. What does it do?

[jusforsean]

Did anybody see the last two GFDL runs for Gordon? Look what it does to Helene:

http://moe.met.fsu.edu/tcgengifs/

I can't see it. What does it do?

it cuts off

[Brent]

...GORDON FORECAST TO TURN WESTWARD...EXPECTED TO REMAIN OVER OPEN
WATERS...



Gordon?

[CronkPSU]

Hurricane Helene Discussion Number 25

Statement as of 11:00 am EDT on September 18, 2006


Helene and Gordon were basically at the same longitude this morning
and there was a weakening on the ridge north of Helene. This
resulted in Helene moving in a north-northwestward track for the
past several hours. However...it appears that the hurricane is
ready to begin the westward turn anticipated by the global models.
In fact...Helene has already turned a little bit and is now moving
toward the northwest or 310 degrees at 8 knots. The trough
currently located over the western Atlantic is forecast to weaken
while a ridge to the north of Helene is expected to amplify. This
pattern would temporarily steer Helene on a westward track for a
couple of days. Thereafter...global models show another large
trough approaching the eastern United States. This trough will
force Helene slowly northward. Although...the confidence is quite
high that Helene will eventually turn northward...it is very
difficult to forecast the longitude this will occur. There are some
indications from the last run of the global models that by days 4
and 5...the steering currents will weaken and Helene will be moving
very slowly.

There has no significant change in the cloud pattern...just a small
increase in the Dvorak T-numbers. Therefore...the intensity has
been adjusted upward to 110 knots. A NOAA P3 plane and NOAA g4
jet...currently on a research mission in the area will be providing
valuable data this afternoon and we could have a better estimate of
the structure of the hurricane and the steering. Helene could
strengthen just little bit more since the shear is low and the
ocean is warm. However...most of the intensity guidance forecast
little change or gradual weakening.


Forecast positions and Max winds


initial 18/1500z 23.2n 50.2w 110 kt
12hr VT 19/0000z 23.9n 51.0w 110 kt
24hr VT 19/1200z 24.3n 52.8w 115 kt
36hr VT 20/0000z 24.3n 54.5w 115 kt
48hr VT 20/1200z 24.5n 56.0w 110 kt
72hr VT 21/1200z 27.0n 58.0w 105 kt
96hr VT 22/1200z 29.5n 59.5w 100 kt
120hr VT 23/1200z 31.5n 60.5w 95 kt


$$
forecaster Avila

[Thunder44]

Did anybody see the last two GFDL runs for Gordon? Look what it does to Helene:

http://moe.met.fsu.edu/tcgengifs/

I can't see it. What does it do?

it cuts off

Yeah, but you see it turn Helene west instead of north.

Anyway, I was just looking at 0z GFS Esembles, I counted 8 out 11 members showing a track further west than the OP run. The first one is you see is the OP run.

http://www.meteo.psu.edu/~gadomski/GFSE ... rloop.html

[Nimbus]

What does "pump up the ridge mean?"

The outflow from Helene builds a high pressure dome over herself.

[gatorcane]

Helene slowly northward. Although...the confidence is quite
high that Helene will eventually turn northward...it is very
difficult to forecast the longitude this will occur. There are some
indications from the last run of the global models that by days 4
and 5...the steering currents will weaken and Helene will be moving
very slowly.

Slowly which way?

[jusforsean]

Helene slowly northward. Although...the confidence is quite
high that Helene will eventually turn northward...it is very
difficult to forecast the longitude this will occur. There are some
indications from the last run of the global models that by days 4
and 5...the steering currents will weaken and Helene will be moving
very slowly.

Slowly which way?

How does the "slowing" affect her steering?

[Josephine96]

Boy that says a lot

[CronkPSU]

climo says except for isabelle, none of the storms in this area even come close to the US, I am guessing it will slow down and then that second trough will push her right out to sea

[OuterBanker]

The more I look at the great wall of China troughs we have been having the more relaxed I get. It's ok by me to have nothing but killer fish this year. Looks like the only way the US mainland will be affected this season by any tropical system is home grown, and I see no signs of that. I see no way Helene could strike the US mainland and that's a good thing. Who knows maybe we will luck out for the entire season. We have only four more weeks of the real season (oct 15) sure hope we make ith through. It looks like we have at least a week of nothing so far, that leaves only three weeks. An eternal optimist.

[Thunder44]

The 12z NOGAPS out 108hrs, now recurves before reaching 60W:

https://www.fnmoc.navy.mil/PUBLIC/index.html

Click MYWXMAP and login as guest.

[Dave C]

Don't know if anyone mentioned this already but neither floater from the TPC is on Helene. Floater 1 is on area near New Foundland while floater 2 is on Gordon.

[Pebbles]

Don't know if anyone mentioned this already but neither floater from the TPC is on Helene. Floater 1 is on area near New Foundland while floater 2 is on Gordon.

That's because you need to look at floater 3

Edit: Here's a link http://www.ssd.noaa.gov/PS/TROP/float3.html