ATL: LESLIE - Models

[Macrocane]

Could be a problem for Canada, like Igor and Juan. Leslie will be one of those long tracker and strong system that is very interesting to track if the models verify.

[HURRICANELONNY]

I don't know if anyone posted the 11am nhc discussion about the long range models:

PARTIALLY RELATED TO
KIRK. WHILE THE RIDGE IS EXPECTED TO REBUILD SOMEWHAT AS KIRK MOVES
OUT TO SEA...ALL OF THE GLOBAL MODELS SHOW TROUGHING BETWEEN
60W-70W IN THE MEDIUM RANGE PERIOD...WHICH WILL PROBABLY TURN THE
CYCLONE TO THE NORTHWEST AND NORTH. THERE IS A LOT OF UNCERTAINTY
IN THE LONG RANGE RELATED TO WHETHER THE SYSTEM RECURVES AHEAD OF
THE TROUGH OR GETS TRAPPED BENEATH A REBUILDING RIDGE. THE NHC
FORECAST IS A BIT FASTER AND WEST OF THE CONSENSUS THROUGHOUT THE
PERIOD...BUT THIS FORECAST STILL KEEPS THE CYCLONE WELL TO THE
NORTHEAST OF THE LESSER ANTILLES.

[Frank2]

Interesting to note that Isaac probably would have recurved too, had it not been weak as it approached the islands - not so with strengthening Leslie...

[floridasun78]

12Z NOGAPS

https://www.fnmoc.navy.mil/wxmap_cgi/cg ... t=Tropical

everyone say that nogap bad for tropical forcasting

[fci]

At the end of the period...speed differences become
very important on whether Leslie moves quickly out to sea...as
suggested by the GFS...or gets stuck under a ridge...as forecast by
the ECMWF. This is from the 5:00 Pm discussion.....

Interesting comment about the divergence of models....
I truly expect the classic recurve but there does seem to be a level of uncertainty..

[bonjourno]

Hmm, why does the Euro seem to just stall it between hours 96 and 192? Barely moves around that ~30N 60W position (maybe a tad north)

[Hybridstorm_November2001]

Hmm, why does the Euro seem to just stall it between hours 96 and 192? Barely moves around that ~30N 60W position (maybe a tad north)

as the NHC disco puts it:


THE INITIAL MOTION IS ABOUT 280/18. LESLIE SHOULD TURN TOWARD THE
WEST-NORTHWEST IN THE NEXT 12 HOURS OR SO AS IT MOVES AROUND THE
SOUTHWESTERN SIDE OF THE SUBTROPICAL RIDGE. A SERIES OF TROUGHS IS
EXPECTED TO DIG BETWEEN 60W-70W...WHICH SHOULD CAUSE THE STORM TO
MAKE A GRADUAL TURN TOWARD THE NORTHWEST AND NORTH IN A FEW DAYS.
MODEL GUIDANCE IS IN VERY GOOD AGREEMENT FOR THE FIRST THREE
DAYS...THEN SOME DIVERGENCE OCCURS ON WHICH TROUGH MIGHT RECURVE
THE CYCLONE. AT THE END OF THE PERIOD...SPEED DIFFERENCES BECOME
VERY IMPORTANT ON WHETHER LESLIE MOVES QUICKLY OUT TO SEA...AS
SUGGESTED BY THE GFS...OR GETS STUCK UNDER A RIDGE...AS FORECAST BY
THE ECMWF. THE NHC FORECAST IS BASICALLY AN UPDATE OF THE
PREVIOUS ONE...STILL A BIT FASTER AND WEST OF THE MODEL CONSENSUS.

[storm4u]

18z gfs is way sw of 12z at hr144

[rainstorm]

yea, i noticed that. a big change

[KWT]

Gosh thats real close call for Bermuda, it just stalls and drifts NE a little to the S/SE of the island. Wouldn't take much shift at all to hit.

[cpdaman]

interesting that at least the gfs and euro both have this stall now, on the operational runs, (haven't look'd at ensembles from euro) and (obviously 18z gfs ens aren't out yet)

but do mets really see this as a distinct possibility, is it too far in the future wxman 57 to say this may have a 50/50 shot.....of becoming an " atlantic ocean swell machine for an extended period"

[TheDreamTraveler]

18z GFS following the 12z Euro...yikes

Here's the 18z GFS





12z Euro from earlier today...falling into agreement this far out isn't that good.

[JamesCaneTracker]

Well I guess I need to pay extra close attention to this... A little shift to the west and I could be looking at a landfall... Going to be a very interesting next couple of weeks!

[angelwing]

Looks like I have to watch this one too.

[cycloneye]

00z Models.

Code: Select all

WHXX01 KWBC 310044
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
0044 UTC FRI AUG 31 2012
 
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 LESLIE (AL122012) 20120831 0000 UTC
 
        ...00 HRS...   ...12 HRS...   ...24 HRS. ..   ...36 HRS...
        120831  0000   120831  1200   120901  0000   120901  1200
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    14.5N  45.9W   15.8N  47.9W   17.7N  50.4W   19.8N  53.5W
BAMD    14.5N  45.9W   15.3N  48.4W   16.3N  50.6W   17.3N  52.5W
BAMM    14.5N  45.9W   15.8N  48.3W   17.4N  50.7W   19.1N  53.3W
LBAR    14.5N  45.9W   15.5N  49.1W   16.4N  52.4W   17.3N  55.7W
SHIP        45KTS          56KTS          67KTS          75KTS
DSHP        45KTS          56KTS          67KTS          75KTS
 
        ...48 HRS...   ...72 HRS...   ...96 HRS. ..   ..120 HRS...
        120902  0000   120903  0000   120904  0000   120905  0000
 
         LAT    LON     LAT    LON     LAT    LON     LAT    LON
BAMS    21.6N  57.0W   24.1N  62.8W   25.5N  66.1W   26.0N  64.7W
BAMD    18.5N  54.0W   21.3N  56.5W   24.3N  57.0W   25.8N  55.4W
BAMM    20.6N  56.1W   23.7N  60.7W   27.0N  63.7W   28.2N  64.5W
LBAR    18.4N  58.5W   20.9N  62.2W   25.8N  63.3W   29.7N  63.6W
SHIP        81KTS          83KTS          85KTS          88KTS
DSHP        81KTS          83KTS          85KTS          88KTS
 
         ...INITIAL CONDITIONS...
LATCUR =  14.5N LONCUR =  45.9W DIRCUR = 280DEG SPDCUR =  16KT
LATM12 =  13.8N LONM12 =  42.6W DIRM12 = 280DEG SPDM12 =  18KT
LATM24 =  13.5N LONM24 =  39.1W
WNDCUR =   45KT RMAXWD =   35NM WNDM12 =   35KT
CENPRS = 1002MB OUTPRS = 1013MB OUTRAD =  250NM SDEPTH =   M
RD34NE =   40NM RD34SE =   30NM RD34SW =    0NM RD34NW =  40NM
 


[Hurricaneman]

0zGFS stalls Leslie at 27N 63W for days on this run

[rainstorm]

yea, 0z gfs is far different from 18z.

http://forums.accuweather.com/index.php ... &id=169322

i wonder if that low off florida is isaacs remains.

[rainstorm]

i wonder if that low will force leslie nw like the euro was showing.

[Riptide]

i wonder if that low will force leslie nw like the euro was showing.

Wow Rainstorm, this looks bad. Cutoff low over the ohio valley, this will come very close to the NE.

[Jevo]

0z HWRF Initialized



0z HWRf +24



0z HWRF +48