Ex Invest 99L Model Runs

[TreasureIslandFLGal]

I have a hunch this will be reborn around 80W and develop into a tropical system after all.

[gatorcane]

CMC has it just NE of the Leewards in 120 hours:

[blp]

18Z GFS has a stronger Ridge building back towards the end of the below run. It has shown this for a few runs now. Seems like this one will make it further West if it stays weak. It also dissipates it around the islands. We will see....

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

[Hurricaneman]

18Z GFS has a stronger Ridge building back towards the end of the below run. It has shown this for a few runs now. Seems like this one will make it further West if it stays weak. It also dissipates it around the islands. We will see....

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

according to this, this low will be near the bahamas in 7 days, but with all model forecasts anything after 3 days needs to be taken with a grain of salt

[cycloneye]

Moving 270 degrees.

893
WHXX01 KWBC 011352
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1352 UTC FRI AUG 1 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 (AL992008) 20080801 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080801 1200 080802 0000 080802 1200 080803 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 18.4N 35.4W 18.5N 38.9W 18.3N 42.4W 18.4N 45.9W
BAMD 18.4N 35.4W 19.0N 37.8W 19.6N 40.3W 20.5N 42.8W
BAMM 18.4N 35.4W 19.0N 38.3W 19.3N 41.3W 20.1N 44.4W
LBAR 18.4N 35.4W 19.0N 38.8W 19.6N 42.3W 20.5N 45.8W
SHIP 25KTS 27KTS 30KTS 33KTS
DSHP 25KTS 27KTS 30KTS 33KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080803 1200 080804 1200 080805 1200 080806 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 18.6N 49.4W 20.6N 56.0W 23.8N 61.8W 27.0N 64.7W
BAMD 21.6N 45.4W 24.4N 50.6W 27.7N 54.7W 30.5N 53.9W
BAMM 21.2N 47.5W 24.5N 53.7W 28.7N 57.4W 32.1N 54.3W
LBAR 21.7N 49.0W 25.6N 54.2W 30.9N 55.3W 34.5N 52.3W
SHIP 37KTS 43KTS 48KTS 51KTS
DSHP 37KTS 43KTS 48KTS 51KTS

...INITIAL CONDITIONS...
LATCUR = 18.4N LONCUR = 35.4W DIRCUR = 270DEG SPDCUR = 20KT
LATM12 = 18.4N LONM12 = 31.4W DIRM12 = 278DEG SPDM12 = 21KT
LATM24 = 18.1N LONM24 = 25.0W
WNDCUR = 25KT RMAXWD = 45NM WNDM12 = 25KT
CENPRS = 1008MB OUTPRS = 1010MB OUTRAD = 150NM SDEPTH = S
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[DESTRUCTION5]

Least ships says TD this time... A fish TD at that..

[HURAKAN]

[drezee]

BAMS says Bermuda Part Deux...

[KWT]

Well right now we need to use the shallow guidence and extrap movement agrees with that as well. I certainly wouldn't duscount a Bermuda threat given Bertha took that route as well and I don't think steering currents have really changed all that much.

[gatorcane]

I do think these models are recurving much too quickly this time. I see no evidence of such a recurve at this time. Two reasons:

-99L should not be any stronger than a T.S through the forecast period (5 days)
-The North Atlantic ridge is building westward in tandem with 99L as evidence by water vapor imagery analysis

I expect these models to shift left over the next few runs.

[stevetampa33614]

I do think these models are recurving much too quickly this time. I see no evidence of such a recurve at this time. Two reasons:

-99L should not be any stronger than a T.S through the forecast period (5 days)
-The North Atlantic ridge is building westward in tandem with 99L as evidence by water vapor imagery analysis

I expect these models to shift left over the next few runs.

Thank you for this GC.

[curtadams]

I notice the models that actually have something (CMC and GFS, and a very weak TS at that) dissipate it to an open wave as it passes above the islands. Shear? The models really don't like it's prospects when even the CMC has it eventually dissipating.

[gatorcane]

TPC shows a low now on their surface analysis (presumably 99L) moving west (see X on right-hand side of pic). It seems to follow the shallow BAM from the above model plots

[cycloneye]

Yes I know,but the 12z Canadian has it passing over me and ending in the Central Bahamas,although in a very weak stage.

http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[Ed Mahmoud]

12Z GFS not widely enthusiastic about this wave either. Passes just North of N.E. Caribbean before starting to round the Bermuda High.

[gatorcane]

Yes takes a very similar path to Becky 1958. I posted that path in the discussion thread. I do agree with the GFS on path at this point...just NE of the Leewards (maybe by only 100 miles or so) and a recurve farther west than 40-45W. But I think there is a decent chance it will be tropical storm before all is said and done.

The key to the long-range forecast is that strong Low pressure system over the northern US/Canada moving east at the end of that run. That should swing a short-wave through the Eastern CONUS and out into the Western Atlantic that should weaken the western periphery of the subtropical ridge. Of course things are still far out but that is why the GFS is forecasting recurvature. I do buy this scenario and think its likely we will see this happen.

Bermuda may have to watch the evolution of 99L again as they did with Bertha.

[cycloneye]

Hey peeps,look what the first plots from GFDL does,dips,dips,dips until dissipation in 48 hours.

Code: Select all

WHXX04 KWBC 011723
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL DEPRESSION INVEST    99L

INITIAL TIME  12Z AUG  1

DISCLAIMER ...  THIS INFORMATION IS PROVIDED AS GUIDANCE.  IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT.  PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.


FORECAST STORM POSITION

HOUR        LATITUDE        LONGITUDE        HEADING/SPEED(KT)

   0            17.9             35.4           270./20.0
   6            17.5             37.0           256./15.6
  12            17.4             39.1           266./19.8
  18            17.4             41.0           268./19.0
  24            17.4             42.9           270./17.8
  30            17.0             44.7           259./16.8
  36            17.1             46.9           271./21.5
  42            17.2             48.8           273./17.9
  48            15.8             51.0           239./25.2

STORM DISSIPATED AT  48 HRS AT THE ABOVE PSN.

GFDL is the red line:

[gatorcane]

interesting Luis about GFDL, not sure if it was a bad run or not

By the same token, I don't see such rapid recurvature forecasted by the deep BAMs either unless 99L was deepening and organizing more quickly which clearly it is not.

[HURAKAN]

Code: Select all

                    *   ATLANTIC SHIPS INTENSITY FORECAST       *
                    *        GOES/OHC INPUT INCLUDED            *
                    *      INVEST  AL992008  08/01/08  12 UTC   *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    25    26    27    28    30    33    37    41    43    45    48    52    51
V (KT) LAND       25    26    27    28    30    33    37    41    43    45    48    52    51
V (KT) LGE mod    25    25    26    26    27    28    29    31    32    35    38    42    46

SHEAR (KTS)       13    12    16    16    17    14    16    12    14    14    10    11    11
SHEAR DIR        258   249   238   247   255   230   230   220   220   192   224   222   267
SST (C)         25.5  25.7  25.9  26.1  26.2  26.7  27.1  27.3  27.5  27.6  27.2  26.8  26.3
POT. INT. (KT)   112   112   114   116   117   123   127   130   132   133   127   122   118
ADJ. POT. INT.   108   107   108   111   112   117   121   123   123   120   111   106   103
200 MB T (C)   -54.0 -53.9 -54.1 -54.6 -54.8 -54.5 -54.8 -54.2 -54.4 -54.4 -54.8 -54.9 -55.2
TH_E DEV (C)       7     7     7     8     8     9     9     9     9    10     9     9     9
700-500 MB RH     50    51    50    47    44    45    43    43    47    48    50    48    48
GFS VTEX (KT)      8     9     8     8     9     7     7     7     6     5     5     4     3
850 MB ENV VOR    39    39    31    17     0   -13   -30   -48   -81  -100  -118  -127  -131
200 MB DIV        -2   -15   -10    13    18   -16    14     1    -2     5    24    13    -6
LAND (KM)       1946  2090  2183  2095  2005  1894  1847  1645  1419  1357  1432  1617  1574
LAT (DEG N)     18.4  18.7  19.0  19.2  19.3  20.1  21.2  22.7  24.5  26.6  28.7  30.7  32.1
LONG(DEG W)     35.4  36.9  38.3  39.8  41.3  44.4  47.5  50.6  53.7  56.0  57.4  56.8  54.3
STM SPEED (KT)    17    14    14    14    15    15    16    16    16    13    10    11    13
HEAT CONTENT       0     0     0     1     3    12    15    17    16    20     9     5     2

  FORECAST TRACK FROM BAMM      INITIAL HEADING/SPEED (DEG/KT):270/ 20      CX,CY: -19/  0
  T-12 MAX WIND:  25            PRESSURE OF STEERING LEVEL (MB):  764  (MEAN=625)
  GOES IR BRIGHTNESS TEMP. STD DEV. 100-300 KM RAD:  21.6 (MEAN=20.0)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  24.0 (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.   0.  -1.   0.   2.   6.  11.  16.  20.  23.  24.  26.
  VERTICAL SHEAR         1.   2.   3.   4.   5.   4.   4.   3.   2.   3.   3.   4.
  PERSISTENCE            0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.   0.   0.
  200/250 MB TEMP.       0.   0.   0.   0.   1.   2.   2.   2.   3.   3.   4.   5.
  THETA_E EXCESS         0.  -1.  -1.  -1.  -1.  -2.  -2.  -3.  -4.  -4.  -5.  -5.
  700-500 MB RH          0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  GFS VORTEX TENDENCY    0.   0.   0.   0.  -1.  -1.  -2.  -3.  -4.  -4.  -5.  -6.
  850 MB ENV VORTICITY   0.   0.   0.   0.   0.  -1.  -2.  -3.  -4.  -6.  -7.  -9.
  200 MB DIVERGENCE      0.  -1.  -1.  -1.  -2.  -2.  -2.  -3.  -3.  -3.  -3.  -3.
  ZONAL STORM MOTION     0.   0.   1.   2.   3.   4.   5.   6.   6.   8.   9.   9.
  STEERING LEVEL PRES    0.  -1.  -1.  -1.  -2.  -3.  -2.  -4.  -4.  -4.  -3.  -3.
  DAYS FROM CLIM. PEAK   0.   0.   0.   0.  -1.  -1.  -2.  -2.  -2.  -2.  -2.  -3.
                        ----------------------------------------------------------
  SUB-TOTAL CHANGE       1.   2.   3.   5.   8.  12.  17.  19.  21.  24.  27.  28.

  SATELLITE ADJUSTMENTS ----------------------------------------------------------
  MEAN ADJUSTMENT        0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -2.
  GOES IR STD DEV        1.   1.   2.   2.   2.   2.   1.   0.  -1.   0.   0.   0.
  GOES IR PIXEL COUNT   -1.  -1.  -2.  -2.  -2.  -1.  -1.   1.   2.   2.   2.   0.
  OCEAN HEAT CONTENT     0.   0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.
                        ----------------------------------------------------------
  TOTAL ADJUSTMENT       0.   0.   0.   0.   0.  -1.   0.   0.  -1.  -1.  -1.  -2.
                        ----------------------------------------------------------
  TOTAL CHANGE (KT)      1.   2.   4.   5.   8.  12.  16.  18.  20.  23.  27.  26.

   ** 2008 ATLANTIC RI INDEX AL992008     INVEST 08/01/08  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) :  14.9 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.6/  1.0
 D200 (10**7s-1)       :   0.8 Range:-20.0 to 149.0 Scaled/Wgted Val:  0.1/  0.2
 POT = MPI-VMAX (KT)   :  84.1 Range: 25.1 to 130.7 Scaled/Wgted Val:  0.6/  0.6
 850-700 MB REL HUM (%):  70.8 Range: 56.0 to  88.0 Scaled/Wgted Val:  0.5/  0.2
 % area w/pixels <-30 C:  22.0 Range: 17.0 to 100.0 Scaled/Wgted Val:  0.1/  0.0
 STD DEV OF IR BR TEMP :  26.5 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.3/  0.4
 Heat content (KJ/cm2) :   0.8 Range:  0.0 to 132.0 Scaled/Wgted Val:  0.0/  0.0
 
 Prob of RI for 25 kt RI threshold=    13% is   1.1 times the sample mean(12.3%)
 Prob of RI for 30 kt RI threshold=     3% is   0.3 times the sample mean( 7.8%)
 Prob of RI for 35 kt RI threshold=     1% is   0.3 times the sample mean( 4.5%)

   ##         ANNULAR HURRICANE INDEX (AHI) AL992008     INVEST 08/01/08  12 UTC         ##
   ## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=6 NFAIL=1                          ##
   ## AHI=  0   (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
   ##     ANNULAR INDEX RAN NORMALLY             

[Blown Away]

Explain why the GFS & GFDL have 99L going WSW and the Bamms have 99L recurving? I thought the Bamms were more reliable in the deep tropics?

http://www.wunderground.com/tropical/tr ... model.html