ATL: Dolly Model Runs

[ronjon]

06Z HWRF shows a path similar to the GFDL although weaker - this run turns it north toward La at the end of its run. It looks like both the GFDL and HWRF are showing a weakness develop over the west-central GOM due to a low pressure trough dropping southward over the central plains to near NW MO in 5 days.

http://moe.met.fsu.edu/cgi-bin/hwrftc2.cgi?time=2008071806-invest94l&field=Sea+Level+Pressure&hour=Animation

[Portastorm]

No doubt the 0z and 6z model cycles are interesting but I wouldn't be too concerned because:

1) No system yet thus no actual center from which a model can initialize

2) While the known models are showing a trend toward Texas and Louisiana, they are primarily the deep tropics models (BAMM, BAMD) and useless ones (CLIP5).

3) The Euro, CMC, and GFS all show the center of whatever system exists by then impacting the NE Mexican coast. These models at least consider the overall synoptics and offer a more "global" approach.

4) The GFDL has been kinda wild in its last few runs, going from NE Mexico to Louisiana. Would like to see more consistency.

[KWT]

Also the other thing is the GFDL has been known to be a little quick in sending systems northwards in the past. I think the global models are in pretty good agreement so no reason not to trust them unless this really does develop quickly in the western Caribbean.

[ronjon]

I wouldn't discount the GFDL since it is one of the best dynamic models available. I agree that the other globals showing a more southern track does make the window pretty large toward the 4 to 5 day period. I'm not making the case that the GFDL is spot on - especially given its sometimes right bias. And of course, it all depends on intensity of the cyclone which is difficult to forecast. All the models have been trending north with time so this could be BOC mexican threat or further north - too soon to tell. Another east coast trough is expected to amplify on Tuesday so this will likely weaken the mid-level ridge somewhere along the gulf coast - whether this system is far enough north to be influenced I have no idea at this time.

[Portastorm]

I wouldn't discount the GFDL since it is one of the best dynamic models available. I agree that the other globals showing a more southern track does make the window pretty large toward the 4 to 5 day period. I'm not making the case that the GFDL is spot on - especially given its sometimes right bias. And of course, it all depends on intensity of the cyclone which is difficult to forecast. All the models have been trending north with time so this could be BOC mexican threat or further north - too soon to tell. Another east coast trough is expected to amplify on Tuesday so this will likely weaken the mid-level ridge somewhere along the gulf coast - whether this system is far enough north to be influenced I have no idea at this time.

Hey ronjon, I think you nailed the questions at hand pretty darn well! The points you raise are all things we need to be watching as this system further develops (or not!). I have to admit, I have been lurking mostly on 94L but the entire episode to date has been fascinating to watch!

[Ed Mahmoud]

From main 94L thread, but I think its worth a double post...

I'm thinking if there is a LLC it may reform under the deepest convection. Right now that is NE of earlier.

I was thinking something similar as well, would not be surprised if that happened, but with this system all bets are off...

This is more of a model thread caveat, but since the center hasn't really been fixed, and may even reform, neither intensity or track models may be exactly properly initialized.


I think I'll copy and paste this in the model thread as well

[cycloneye]

No TD yet:

WHXX01 KWBC 181322
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1322 UTC FRI JUL 18 2008

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

DISTURBANCE INVEST (AL942008) 20080718 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080718 1200 080719 0000 080719 1200 080720 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 13.7N 71.0W 14.7N 74.4W 15.7N 78.0W 16.8N 81.6W
BAMD 13.7N 71.0W 14.2N 73.4W 15.0N 76.1W 16.1N 78.8W
BAMM 13.7N 71.0W 14.6N 73.8W 15.6N 76.8W 16.8N 79.8W
LBAR 13.7N 71.0W 14.5N 74.1W 15.5N 77.5W 16.7N 80.8W
SHIP 30KTS 35KTS 42KTS 48KTS
DSHP 30KTS 35KTS 42KTS 48KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080720 1200 080721 1200 080722 1200 080723 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 17.6N 85.0W 18.6N 89.8W 19.5N 92.8W 21.0N 94.6W
BAMD 17.2N 81.4W 19.1N 86.2W 21.2N 90.2W 22.7N 92.6W
BAMM 18.0N 82.7W 19.9N 87.6W 22.2N 91.6W 24.2N 94.2W
LBAR 17.9N 84.1W 20.3N 89.9W 23.2N 94.4W 25.0N 96.6W
SHIP 54KTS 67KTS 74KTS 74KTS
DSHP 54KTS 56KTS 44KTS 44KTS

...INITIAL CONDITIONS...
LATCUR = 13.7N LONCUR = 71.0W DIRCUR = 280DEG SPDCUR = 16KT
LATM12 = 13.2N LONM12 = 68.0W DIRM12 = 281DEG SPDM12 = 17KT
LATM24 = 12.6N LONM24 = 64.2W
WNDCUR = 30KT RMAXWD = 45NM WNDM12 = 30KT
CENPRS = 1008MB OUTPRS = 1011MB OUTRAD = 150NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

$$
NNNN

[KWT]

SHIPS takes this upto 56kts, makes it upto a strong tropical storm then so we will have to wait and see what happens.

[cycloneye]

SHIP forecast from 12:00 UTC: Shear looks like not a problem.RI goes up to 40%.

Code: Select all

ATLANTIC SHIPS INTENSITY FORECAST       *
                    *        GOES/OHC INPUT INCLUDED            *
                    *      INVEST  AL942008  07/18/08  12 UTC   *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    30    32    35    39    42    48    54    63    67    72    74    75    74
V (KT) LAND       30    32    35    39    42    48    54    63    56    38    44    44    44
V (KT) LGE mod    30    30    30    31    32    35    40    45    45    33    43    51    58

SHEAR (KTS)       23    17    10    12    11    10    12     6     2     7     8     6    14
SHEAR DIR        318   333   290   289   318   267   327   232   299   221   352   336   354
SST (C)         27.5  27.7  27.9  28.0  28.1  28.3  28.4  28.7  28.0  27.7  28.1  28.5  28.4
POT. INT. (KT)   132   134   137   139   140   143   144   148   137   133   138   143   141
ADJ. POT. INT.   132   134   137   139   140   142   140   142   129   123   126   128   124
200 MB T (C)   -54.8 -54.3 -54.0 -54.3 -54.3 -53.8 -53.9 -53.2 -53.6 -52.5 -53.2 -52.7 -53.1
TH_E DEV (C)       9    11    10    10    10    11     8    11     8    10     7    10     8
700-500 MB RH     67    68    70    68    66    63    66    66    69    69    67    67    67
GFS VTEX (KT)      9     9     8     9     8     8     8    10    10    11    11     8     7
850 MB ENV VOR    16    17    25    39    38    34    30    32    28    12    11    26    22
200 MB DIV        35    59    56    40    51    48     9    54    27    82     6    37    18
LAND (KM)        153   198   325   314   237   222   291   228   -23   -16   189   385   349
LAT (DEG N)     13.7  14.2  14.6  15.1  15.6  16.8  18.0  19.1  19.9  21.0  22.2  23.4  24.2
LONG(DEG W)     71.0  72.4  73.8  75.3  76.8  79.8  82.7  85.3  87.6  89.7  91.6  93.0  94.2
STM SPEED (KT)    14    14    15    15    15    16    14    13    11    11    10     8     7
HEAT CONTENT      27    28    49    61    74    70    74    57  9999     0    18    49    27

  FORECAST TRACK FROM BAMM      INITIAL HEADING/SPEED (DEG/KT):280/ 16      CX,CY: -15/  3
  T-12 MAX WIND:  30            PRESSURE OF STEERING LEVEL (MB):  639  (MEAN=625)
  GOES IR BRIGHTNESS TEMP. STD DEV. 100-300 KM RAD:  17.4 (MEAN=20.0)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  98.0 (MEAN=68.6)

                        INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
                         6   12   18   24   36   48   60   72   84   96  108  120
                        ----------------------------------------------------------
  SAMPLE MEAN CHANGE     1.   2.   3.   4.   6.   8.   9.  10.  11.  12.  12.  13.
  SST POTENTIAL          0.   1.   1.   2.   6.  11.  17.  20.  24.  26.  28.  29.
  VERTICAL SHEAR         0.   1.   1.   2.   3.   3.   4.   5.   7.   7.   8.   8.
  PERSISTENCE            0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.   0.   0.
  200/250 MB TEMP.       0.   0.   0.   1.   1.   1.   1.   1.   1.   1.   1.   1.
  THETA_E EXCESS         0.   0.   0.   0.   0.  -1.  -1.  -1.  -2.  -3.  -3.  -4.
  700-500 MB RH          0.   0.   0.   0.   0.   0.   0.   0.   0.   0.  -2.  -2.
  GFS VORTEX TENDENCY    0.   0.   0.  -1.  -2.  -1.   0.   0.   0.   0.  -2.  -3.
  850 MB ENV VORTICITY   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  200 MB DIVERGENCE      0.   0.   1.   1.   2.   2.   2.   3.   4.   3.   3.   3.
  ZONAL STORM MOTION     0.   0.   1.   1.   2.   3.   3.   4.   4.   5.   6.   6.
  STEERING LEVEL PRES    0.   0.   0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.
  DAYS FROM CLIM. PEAK   0.   0.   0.  -1.  -1.  -2.  -2.  -2.  -2.  -3.  -3.  -4.
                        ----------------------------------------------------------
  SUB-TOTAL CHANGE       1.   3.   6.   9.  16.  22.  32.  38.  45.  48.  48.  47.

  SATELLITE ADJUSTMENTS ----------------------------------------------------------
  MEAN ADJUSTMENT        0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -2.
  GOES IR STD DEV        1.   2.   2.   2.   2.   2.   1.   0.  -1.   0.   0.   0.
  GOES IR PIXEL COUNT    0.   1.   1.   1.   1.   1.   0.   0.  -1.  -1.  -1.   0.
  OCEAN HEAT CONTENT     0.   0.   0.   0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.
                        ----------------------------------------------------------
  TOTAL ADJUSTMENT       1.   2.   3.   3.   3.   2.   1.  -1.  -4.  -3.  -3.  -3.
                        ----------------------------------------------------------
  TOTAL CHANGE (KT)      2.   5.   9.  12.  18.  24.  33.  37.  42.  44.  45.  44.

   ** 2008 ATLANTIC RI INDEX AL942008     INVEST 07/18/08  12 UTC **
           ( 25 KT OR MORE MAX WIND INCREASE IN NEXT 24 HR)
 
 12 HR PERSISTENCE (KT):   0.0 Range:-45.0 to  30.0 Scaled/Wgted Val:  0.6/  1.1
 850-200 MB SHEAR (KT) :  14.4 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.7/  1.0
 D200 (10**7s-1)       :  48.2 Range:-20.0 to 149.0 Scaled/Wgted Val:  0.4/  0.6
 POT = MPI-VMAX (KT)   : 106.2 Range: 25.1 to 130.7 Scaled/Wgted Val:  0.8/  0.9
 850-700 MB REL HUM (%):  73.0 Range: 56.0 to  88.0 Scaled/Wgted Val:  0.5/  0.2
 % area w/pixels <-30 C:  95.0 Range: 17.0 to 100.0 Scaled/Wgted Val:  0.9/  0.2
 STD DEV OF IR BR TEMP :   5.3 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.9/  1.2
 Heat content (KJ/cm2) :  47.8 Range:  0.0 to 132.0 Scaled/Wgted Val:  0.4/  0.0
 
 Prob of RI for 25 kt RI threshold=    40% is   3.2 times the sample mean(12.3%)
 Prob of RI for 30 kt RI threshold=    22% is   2.9 times the sample mean( 7.8%)
 Prob of RI for 35 kt RI threshold=     9% is   2.0 times the sample mean( 4.5%)

   ##         ANNULAR HURRICANE INDEX (AHI) AL942008     INVEST 07/18/08  12 UTC         ##
   ## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=3 NFAIL=4                          ##
   ## AHI=  0   (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
   ##     ANNULAR INDEX RAN NORMALLY 

[KWT]

Yep shear is really progged to drop readily soon, indeed SHIPS has this down to 10kts in just 12hrs though IMO this may have already happened but conditions do look better coming up for some steady strengthening to occur.

[gatorcane]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Here is the GFS at 72 hours:



Note how it has 94L moving into the NW Caribbean a little South of Cuba. That is quite a NW turn. The bottom-line with 94L is this. If it deepens more quickly than expected expect more of a NW turn quicker. A weaker system would tend to stay W with a gradual WNW turn into the Yucatan or farther south.

Looking at the synoptics as shown by the GFS I am not seeing any good heights across the Eastern CONUS really at least for the next 3-4 days. For example here is the GFS forecast for 84 hours.



Beyond that heights build in which could allow for a bend back to the West. My current thinking is that 94L strengthens with favorable conditions in the Western Caribbean with a bend to the WNW then NW for some small amount of time, then bends back to the WNW and W as heights increase over the Eastern CONUS. I do think 94L has a chance of becoming a hurricane though.

[oyster_reef]

[quote="RL3AO"]Wake me up when its not an outlier. Right now the most likely track is an open tropical wave into Central America.


someone wake up RL3AO...

[gatorcane]

Wake me up when its not an outlier. Right now the most likely track is an open tropical wave into Central America.


someone wake up RL3AO...

Indeed the faster 94L organizes the better chance it has in curving NW and away from Central America and the yucatan. There are clear weaknesses NW of 94L at least for the next 3-4 days, after that some ridging *should* (hopefully) build in.

To say it will crash into central america as an open wave is not accurate at this time.

[RL3AO]

Wake me up when its not an outlier. Right now the most likely track is an open tropical wave into Central America.


someone wake up RL3AO...

I did actually just wake up.

[Portastorm]

The 12z GFS run develops 94L and puts the 850mb vortmax in the Yucatan Channel at 54 hrs:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/images/gfs_85v_054l.gif

[Portastorm]

The 12z GFS run at 72 hrs, clearly a surface cyclone in the western Gulf:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/images/gfs_85v_072l.gif

[Wx_Warrior]

Nice high...Let's hope it stays there!!!!

[Portastorm]

Indeed ... it really puts the squeeze on the system as evidenced at 96 hrs:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/images/gfs_85v_096l.gif

[Stormcenter]

Nice high...Let's hope it stays there!!!!

It "should" stay there through next week but we all know things can change.

[Portastorm]

Jinkies!! ... a Brownsville hit @ 120 hrs, so says the 12z GFS:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/images/gfs_85v_120l.gif