Low Pressure near Northern Leewards

[ronjon]

This mornings models showing signs of some sort of tropical development near PR and moving generally W-NW to near Cuba or FL Straits this weekend. The CMC, NAM, NOGAPs, FSU MM5, and GFS all show low pressure development.

http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2007102200&field=Sea+Level+Pressure&hour=Animation

http://moe.met.fsu.edu/cgi-bin/ngptc2.cgi?time=2007102200&field=Sea+Level+Pressure&hour=Animation

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/nam/06/index_slp_s_loop.shtml

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/images/gfs_ten_192s.gif

[cycloneye]

I haved been posting the runs of the models in the Late October/Early November Development thread and they were all over the place in the basin with something forming in the next 10 days,But with what the latest models are showing in less than 200 hours,it is better to continue this new fresh thread to see what comes out of the model scenarios in the next few days.

[Sanibel]

So far the models have been busting for the Caribbean.

[Vortex]

12Z NAM is very agressive with western carribean development. In fact, it's the strongest I've seen the nam in some time...


http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

[GCANE]

I agree, this looks very probable for a system to form somewhere around the Virgin Islands, Puerto Rico around Thursday or Friday, the 25th / 26th.

I believe this will develop from a TUTT that has formed south of an ULL. This can be seen on the WV Image. The ULL is located at 26N 46W. The TUTT exists south of this between the ULL and ITCZ. This can be seen by the UL High that shows on WV and its center is roughly 13N 45W. CIMSS shows this well on the 200-700mb Steering Layers.

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

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm6.html

Anything that develops under the UL High will move west and then NW as it becomes influnced by the High to its north. That high will be moving east and give the system a NW kick in a couple days.

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm1.html

Shear is slowly diminishing under the UL High now:

http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

[boca]

First welcome to S2K GCANE. It looks like the ULL is at 39W and 26N is that the area which your talking about because at 46W and 26N looks like the western edge of that frontal low.
http://www.ssd.noaa.gov/goes/east/catl/avn-l.jpg

Also its getting too late in the year for any system to travel west too long before lifting north due to the westerlies.

[Vortex]

Latest Visible shows the weak LLC/MLC about 120mi ese of Guadeloupe steadily moving W/WNW. Also, the 12z GFS is rolling in and continues development of low pressure

H+42
http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_042l.gif

H+54
http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_054l.gif

H+72 Just NE of San Juan

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_072l.gif

[wxman57]

I don't see any rotation. Just a weak tropical wave in a high-shear environment. Tropical development highly unlikely over the coming week, though I wouldn't rule out 1 or 2 more named storms before the season ends. West Caribbean and the subtropical Atlantic are the most likely areas for late-season development.

And the NAM and Canadian models should not allowed to be posted in a tropical forum.

[GCANE]

Boca:

Thanks for the welcome and thanks for the correction. My mistake, the ULL is indeed at 26N 39W. Also, I agree on the system getting pulled north and that is confirming the models showing a system roughly north of Puerto Rico by the end of the week.

[cycloneye]

10/22/07 12z GFS





GFS continues to show a low near Puerto Rico in 120 hours.

[Derek Ortt]

And the NAM and Canadian models should not allowed to be posted in a tropical forum

lets add the mid latitude EURO model as well. It has had just as stellar of a record as the Canadian and NAM

I'm tempted to start looking at model NCEP again given the other performances this year

[DESTRUCTION5]

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

Umm..is that the Zero Degree line I see dip down into Atlanta? I'd call that if it comes to fruition the offical "Season Cancel" for the CONUS...

[JonathanBelles]

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/index_ten_l_loop.shtml

Umm..is that the Zero Degree line I see dip down into Atlanta? I'd call that if it comes to fruition the offical "Season Cancel" for the CONUS...

that 0°C line come into FL!! I know its about 300 hours out, but thats the earlies I have ever seen that line this far south.

[wxman57]

And the NAM and Canadian models should not allowed to be posted in a tropical forum

lets add the mid latitude EURO model as well. It has had just as stellar of a record as the Canadian and NAM

I'm tempted to start looking at model NCEP again given the other performances this year

Perhaps it was just a coincidence, but the European model was absolutely the best model for Dean and Felix. In 2004, the best model was often LBAR.

[GCANE]

QuikSCAT is showing some convection associated with a surface trough around 11N 46W.

http://manati.orbit.nesdis.noaa.gov/dat ... MBds26.png

This is sitting underneath an UL High:

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm6.html

Shear is about 15 knots, but dropping:

http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

It looks like this is what the GFS is initializing on for the system that will be north of PR by the end of the week:

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

It looks like it may have some trouble with shear for the next couple days however. That will hinder any type of quick development.

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[Steve H.]

Interesting tidbit: Form the HPC Disco
WESTERN CARIBBEAN SEA...
BY THIS WEEKEND...A FRONTAL DROPPING DOWN FROM THE NORTH AND A
TROPICAL WAVE MOVING IN FROM THE EAST COMBINE WITH DIVERGENCE
ALOFT TO LOWER PRESSURES ACROSS THE WESTERN CARIBBEAN SEA. THE
CANADIAN FORMS VARIOUS TROPICAL LOWS NEAR THE WEST INDIES ON ITS
00Z AND 12Z RUN...WHILE THE ECMWF FORMS A SYSTEM DUE TO A
SHORTWAVE MOVING THROUGH THE GULF OF MEXICO. THE GFS FORMS
GRIDSCALE FEEDBACK BULLS EYES WHICH MOVE ALONG THE GREATER
ANTILLES THROUGH THE YUCATAN CHANNEL INTO THE YUCATAN PENINSULA BY
LATE IN THE PERIOD. THE LATEST RUN FROM THE ROUNDY TROPICAL
CYCLONE PROBABILITY WEBSITE INDICATES A GREATER THAN 80 PERCENT
CHANCE OF A TROPICAL CYCLONE ACROSS THE NORTHWEST CARIBBEAN THIS
WEEKEND INTO EARLY NEXT WEEK. AFTER COORDINATION WITH TPC...FORM
THE LOW BY SATURDAY MORNING BEFORE DRIFTING IT WEST.

NOGAPS shows it in the SE Bahamaas and moving WNW throught the Florida Staits

[cycloneye]

14n looks like the area to watch NE of Barbados and east of Martinique.But shear is strong there.

And NOGAPS joins the GFS forming something North of PR.

12z NOGAPS

[wxman57]

I suggest looking at a long-term water vapor satellite loop. Quite strong WSW winds aloft in the path of this weak tropical wave. The wave axis, by the way, is approaching 60W. I don't see anything at 46W (except for a weak upper-level high and no convection). GFS is forecasting 40-50kt WSW winds at 200mb across the NW Caribbean by this weekend into early next week. Not exactly a favorable environment for development. Wind shear would be low in the SW Caribbean north of Panama, however.

A lot of grasping at straws in this thread. We do still need to watch the SW-W Caribbean fro development potential over the coming weeks. But there may be more of a chance of development east of Nicaragua (Beta 2005) than in the NW Caribbean.

QuikSCAT is showing some convection associated with a surface trough around 11N 46W.

http://manati.orbit.nesdis.noaa.gov/dat ... MBds26.png

This is sitting underneath an UL High:

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm6.html

Shear is about 15 knots, but dropping:

http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

It looks like this is what the GFS is initializing on for the system that will be north of PR by the end of the week:

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

It looks like it may have some trouble with shear for the next couple days however. That will hinder any type of quick development.

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[ronjon]

TPC indicates a wave axis along the Lesser Antilles tomorrow at 8 am moving it west over 72 hrs. Shear is strong now but perhaps it will weaken in a couple of days. I noticed todays 12Z CMC basically bombs out a hurricane in the northern Leewards in 3-5 days. Here's the 12Z NOGAPs that Steve H referred to:

http://moe.met.fsu.edu/cgi-bin/ngptc2.cgi?time=2007102212&field=Sea+Level+Pressure&hour=Animation

[wxman57]

Paul Roundy's forecast model actually forecasts development in the NW Caribbean between tomorrow and Friday, not over the weekend. Chances drop off significantly by Saturday. But it's just an experimental forecast scheme. Development chances look remote over the next 3-5 days. Here's Paul's forecast page:

http://www.atmos.albany.edu/facstaff/roundy/tcforecast/tcforecast.html

Interesting tidbit: Form the HPC Disco
WESTERN CARIBBEAN SEA...
BY THIS WEEKEND...A FRONTAL DROPPING DOWN FROM THE NORTH AND A
TROPICAL WAVE MOVING IN FROM THE EAST COMBINE WITH DIVERGENCE
ALOFT TO LOWER PRESSURES ACROSS THE WESTERN CARIBBEAN SEA. THE
CANADIAN FORMS VARIOUS TROPICAL LOWS NEAR THE WEST INDIES ON ITS
00Z AND 12Z RUN...WHILE THE ECMWF FORMS A SYSTEM DUE TO A
SHORTWAVE MOVING THROUGH THE GULF OF MEXICO. THE GFS FORMS
GRIDSCALE FEEDBACK BULLS EYES WHICH MOVE ALONG THE GREATER
ANTILLES THROUGH THE YUCATAN CHANNEL INTO THE YUCATAN PENINSULA BY
LATE IN THE PERIOD. THE LATEST RUN FROM THE ROUNDY TROPICAL
CYCLONE PROBABILITY WEBSITE INDICATES A GREATER THAN 80 PERCENT
CHANCE OF A TROPICAL CYCLONE ACROSS THE NORTHWEST CARIBBEAN THIS
WEEKEND INTO EARLY NEXT WEEK. AFTER COORDINATION WITH TPC...FORM
THE LOW BY SATURDAY MORNING BEFORE DRIFTING IT WEST.

NOGAPS shows it in the SE Bahamaas and moving WNW throught the Florida Staits