18z update of tropical models tracks shows a west shift

#1 Postby **cycloneye** » Thu Jul 31, 2003 2:43 pm

http://files.hurricanealley.net/storms/90LTRP.html

Only GFDL has a north bias but that run is old so that will change with the next run tonight.What a day makes from a fish system to a threatening one to be for the islands but hopefully if it develops it is not a strong system meaning a hurricane.

mf_dolphin · #2 Postby **mf_dolphin** » Thu Jul 31, 2003 2:50 pm

Well the good new Luis is if the average track was to verify then it should stay well south of you :-)

ColdFront77 · #3 Postby **ColdFront77** » Thu Jul 31, 2003 2:56 pm

As I mentioned in another thread, I wouldn't consider the former model run showing a "fish storm" -- it showed a curve, but the end points of all models were far from showing a turn to the N, NNE to eventually NE as of course the models can't go out beyond so many hours.

Johnny · #4 Postby **Johnny** » Thu Jul 31, 2003 3:03 pm

This looks pretty reasonable BUT the models will change again. As I said yesterday.....people down in the islands need to start preparing for the worst just in case.

ColdFront77 · #5 Postby **ColdFront77** » Thu Jul 31, 2003 3:13 pm

It only makes sense that the models change from what they say now.

The more the model guidance changes the more interesting the track of a tropical disturbance/tropical cyclone is.

How can this system possibly dissipate 102 hours from the time these forecast models were made?

southerngale · #6 Postby **southerngale** » Thu Jul 31, 2003 3:32 pm

As the Models Turn...

OtherHD · #7 Postby **OtherHD** » Thu Jul 31, 2003 3:39 pm

Speaking of models...most of the globals lose the system...

Lindaloo · #8 Postby **Lindaloo** » Thu Jul 31, 2003 3:40 pm

Luis.. I pray that this system, wherever it may go, stays far away from you!!

Good one Kelly!! :lol:

Stormsfury · #9 Postby **Stormsfury** » Thu Jul 31, 2003 3:58 pm

IMO, this is getting complicated ...

The GFDL may be initializing the wrong area, period ... and focusing on what looks like the MLC, or what's left of it. In fact, the LLC is nowhere near that area (so this may be quite an old run of the GFDL).

The LLC, though, not as pronounced as yesterday, is more embedded in the around 9ºN around the convective ring, and more in line where the clustering of the other models are now ... Invest 90L still suffers from easterly shear and I believe the LLC is around 9.3ºN, and 37ºW ... or just NE of the deeper convection ...

Whatever the case, looks like we're witnessing a separation of the MLC and LLC ...

SF

ColdFront77 · #10 Postby **ColdFront77** » Thu Jul 31, 2003 4:08 pm

A tropical cyclone has a surface low with low pressure circulations aloft northwest of each other, the higher up into the atmosphere. So the MLC and LLC separating in the "right locations" would be prime for development.

Stormsfury · #11 Postby **Stormsfury** » Thu Jul 31, 2003 4:49 pm

ColdFront77 wrote:A tropical cyclone has a surface low with low pressure circulations aloft northwest of each other, the higher up into the atmosphere. So the MLC and LLC separating in the "right locations" would be prime for development.

In this case, the decaying area northeast of the LLC is somewhat robbing the LLC's moisture on the northern end ... however, as that area pulls away and weakens, I'm expecting a better inflow and an increase of convection around the northern end of the LLC and IMO, Invest 90L will be a depression very soon ... if not, by tonight.

SF

ColdFront77 · #12 Postby **ColdFront77** » Thu Jul 31, 2003 4:51 pm

I understand, Mike. I wanted to make a point with lows aloft in relation to the surface low pressure which is in fact a tropical cyclone's center. Thanks.

#13 Postby **Air Force Met** » Thu Jul 31, 2003 5:07 pm

Most of the models are also moving it too slow. The GFS only has it at 40W by Sat morning...it is only 180 miles from that long right now. So...take all that into account as well.

ColdFront77 · #14 Postby **ColdFront77** » Thu Jul 31, 2003 6:34 pm

We are 36 hours from Saturday morning now, 180 miles away from 40.0ºW will put it to 5 miles per hour. I'll say that would be quite a slow down.

Stormsfury · #15 Postby **Stormsfury** » Thu Jul 31, 2003 6:49 pm

The GFS model data ingested was likely the 12z run, not the 18z run (if the updates come from PSU)

Like Tom stated, we all know that 90L will not move at 5 mph in a deep easterly environment.

SF

18z update of tropical models tracks shows a west shift

18z update of tropical models tracks shows a west shift

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