Tropical Storm Bertha Model Runs

[Aric Dunn]

12z nogaps.. gets pulled north then stalls
.. https://www.fnmoc.navy.mil/wxmap_cgi/cg ... 2008070512

well there is one consensus with the models.. the first trough misses bertha

[cycloneye]

12 z nogaps turns Bertha out to sea..most models have been shifting north throughout the day...next model run will be interesting to see if they continue to show Bertha being picked up by the 2nd trough...

Those models have a stronger storm vs UKMET that has a weak storm.Lets see what the EURO has.

[cycloneye]

Moving 275 at 19kts,Same intensity,45kts.

WHXX01 KWBC 051836
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1836 UTC SAT JUL 5 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

TROPICAL CYCLONE BERTHA (AL022008) 20080705 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080705 1800 080706 0600 080706 1800 080707 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 16.6N 38.4W 17.4N 41.8W 18.3N 45.2W 19.0N 48.5W
BAMD 16.6N 38.4W 17.9N 41.7W 19.1N 45.0W 20.3N 47.6W
BAMM 16.6N 38.4W 17.6N 41.7W 18.6N 45.2W 19.5N 48.2W
LBAR 16.6N 38.4W 17.2N 42.0W 18.4N 45.9W 19.2N 49.6W
SHIP 45KTS 49KTS 53KTS 57KTS
DSHP 45KTS 49KTS 53KTS 57KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080707 1800 080708 1800 080709 1800 080710 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 19.6N 51.6W 20.1N 56.4W 21.4N 59.7W 22.8N 62.4W
BAMD 21.3N 49.3W 23.2N 50.4W 24.4N 49.6W 24.0N 50.0W
BAMM 20.2N 50.5W 21.5N 53.7W 23.1N 55.6W 24.3N 57.7W
LBAR 20.2N 52.8W 21.8N 56.9W 23.7N 57.9W 24.9N 59.5W
SHIP 63KTS 70KTS 69KTS 70KTS
DSHP 63KTS 70KTS 69KTS 70KTS

...INITIAL CONDITIONS...
LATCUR = 16.6N LONCUR = 38.4W DIRCUR = 275DEG SPDCUR = 19KT
LATM12 = 16.3N LONM12 = 34.4W DIRM12 = 280DEG SPDM12 = 18KT
LATM24 = 15.4N LONM24 = 30.8W
WNDCUR = 45KT RMAXWD = 30NM WNDM12 = 45KT
CENPRS = 1000MB OUTPRS = 1012MB OUTRAD = 180NM SDEPTH = D
RD34NE = 75NM RD34SE = 30NM RD34SW = 0NM RD34NW = 75NM

[Ivanhater]

Updated model runs..interesting...

[cycloneye]

Here is the 18:00 UTC SHIP forecast.

Code: Select all

ATLANTIC SHIPS INTENSITY FORECAST       *
                    *        GOES/OHC INPUT INCLUDED            *
                    *      BERTHA  AL022008  07/05/08  18 UTC   *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    45    46    49    51    53    57    63    67    70    66    69    69    70
V (KT) LAND       45    46    49    51    53    57    63    67    70    66    69    69    70
V (KT) LGE mod    45    46    47    48    50    55    60    66    70    70    69    70    70

SHEAR (KTS)        9    13     9     7    11    10     8    21    18    25    16    22    15
SHEAR DIR        185   185   187   188   167   204   199   227   213   237   235   237   246
SST (C)         25.3  25.5  25.8  25.9  26.1  26.7  27.4  27.9  27.8  27.8  28.0  28.1  28.1
POT. INT. (KT)   111   112   115   116   118   124   131   137   135   135   137   139   139
ADJ. POT. INT.   109   110   113   114   115   121   128   131   128   125   125   126   125
200 MB T (C)   -53.9 -54.1 -54.5 -54.7 -54.2 -54.3 -54.3 -54.4 -54.9 -55.0 -55.5 -55.3 -55.9
TH_E DEV (C)       5     6     6     7     7     8    10    10    10    10    10    11    12
700-500 MB RH     55    54    52    49    47    46    39    43    46    43    47    43    42
GFS VTEX (KT)     14    14    14    13    12    12    13    13    15    12    12    10    10
850 MB ENV VOR   115   112   100    82    60    53    39    25    38     4     0   -26   -38
200 MB DIV        23    21    33    52    62    37    46    35    11     4    28    24    19
LAND (KM)       1980  1866  1764  1667  1593  1509  1261  1016   771   623   580   644   646
LAT (DEG N)     16.6  16.9  17.1  17.5  17.8  18.6  19.2  20.1  21.2  22.3  23.3  24.3  25.3
LONG(DEG W)     38.4  40.3  42.1  44.0  45.9  49.5  53.1  56.2  59.0  61.5  63.8  66.0  68.2
STM SPEED (KT)    19    18    18    18    18    17    17    14    14    12    11    11    11
HEAT CONTENT       0     0     0     0     2    16    30    43    38    28    30    34    37

  FORECAST TRACK FROM OFCI      INITIAL HEADING/SPEED (DEG/KT):275/ 19      CX,CY: -18/  2
  T-12 MAX WIND:  45            PRESSURE OF STEERING LEVEL (MB):  653  (MEAN=625)
  GOES IR BRIGHTNESS TEMP. STD DEV. 100-300 KM RAD:  22.5 (MEAN=20.0)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  76.0 (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.   0.   1.   2.   4.   6.   9.  10.  11.  12.  12.
  VERTICAL SHEAR         0.   1.   2.   3.   4.   6.   4.   3.   1.   0.  -1.  -1.
  PERSISTENCE            0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.   0.   0.
  200/250 MB TEMP.       0.   0.   0.   0.   1.   1.   2.   2.   3.   4.   5.   6.
  THETA_E EXCESS         0.  -1.  -1.  -2.  -2.  -2.  -3.  -3.  -4.  -4.  -4.  -4.
  700-500 MB RH          0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  GFS VORTEX TENDENCY    0.   0.  -1.  -1.  -2.  -1.  -1.   0.  -3.  -3.  -5.  -5.
  850 MB ENV VORTICITY   1.   1.   2.   2.   2.   3.   3.   3.   3.   2.   2.   1.
  200 MB DIVERGENCE      0.   0.   0.   1.   1.   2.   2.   2.   1.   1.   1.   1.
  ZONAL STORM MOTION     0.   0.   1.   2.   3.   3.   4.   5.   6.   7.   8.   9.
  STEERING LEVEL PRES    0.   0.   0.   0.   0.  -1.  -1.  -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.   7.  12.  19.  23.  26.  23.  26.  26.  27.

  SATELLITE ADJUSTMENTS ----------------------------------------------------------
  MEAN ADJUSTMENT        0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -2.
  GOES IR STD DEV        0.   0.   0.   1.   1.   0.   0.   0.   0.   0.   0.   0.
  GOES IR PIXEL COUNT    0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  OCEAN HEAT CONTENT     0.   0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.
                        ----------------------------------------------------------
  TOTAL ADJUSTMENT       0.   0.   0.   0.   0.   0.  -1.  -2.  -2.  -2.  -2.  -2.
                        ----------------------------------------------------------
  TOTAL CHANGE (KT)      1.   4.   6.   8.  12.  19.  22.  25.  21.  24.  24.  25.

   ** 2008 ATLANTIC RI INDEX AL022008     BERTHA 07/05/08  18 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) :   9.7 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.8/  1.3
 D200 (10**7s-1)       :  38.2 Range:-20.0 to 149.0 Scaled/Wgted Val:  0.3/  0.5
 POT = MPI-VMAX (KT)   :  67.1 Range: 25.1 to 130.7 Scaled/Wgted Val:  0.4/  0.5
 850-700 MB REL HUM (%):  71.0 Range: 56.0 to  88.0 Scaled/Wgted Val:  0.5/  0.2
 % area w/pixels <-30 C:  64.0 Range: 17.0 to 100.0 Scaled/Wgted Val:  0.6/  0.1
 STD DEV OF IR BR TEMP :  13.0 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.7/  0.9
 Heat content (KJ/cm2) :   0.4 Range:  0.0 to 132.0 Scaled/Wgted Val:  0.0/  0.0
 
 Prob of RI for 25 kt RI threshold=    22% is   1.8 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) AL022008     BERTHA 07/05/08  18 UTC         ##
   ## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3                          ##
   ## AHI=  0   (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
   ##     ANNULAR INDEX RAN NORMALLY     

[tailgater]

For entertainment purposes only.
http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

[Aric Dunn]

http://www.nhc.noaa.gov/archive/2008/gr ... p_5W.shtml

[Aric Dunn]

new update ..

[cycloneye]

The 12z EURO has a strong Bertha just off the coast of New Jersey and Long island.

http://www.ecmwf.int/products/forecasts ... 7091412!!/

[Aric Dunn]

The 12z EURO has a strong Bertha just off the coast of New Jersey and Long island.

http://www.ecmwf.int/products/forecasts ... 7091412!!/

wow hows that loop it does.. geezz that would be interesting...

[Cyclone1]

Holy... talk about a shift. Haven't check the models in a while.. this is news.

[Ivanhater]

The 12z EURO has a strong Bertha just off the coast of New Jersey and Long island.

http://www.ecmwf.int/products/forecasts ... 7091412!!/

wow hows that loop it does.. geezz that would be interesting...

What I think the models are having a hard time right now is they are picking up on the 2nd trough to try picking Bertha up but is not strong enough to do the job so Bertha stalls out while the ridge builds back in and pushes her back west..Wxman alluded to this earlier, and this may be what the models are just now sniffing out..something to look for in the next runs..look for a turn towards to NW but look for the models to bend her back west later in the forecast.

[deltadog03]

I think most models are still moving here more on a NW or WNW line in the short term....Clearly she is moving more of the DUE WEST right now, (and has been for 12 hours)

[MiamiensisWx]

I'll repost an original summary from the other thread here, since it pertains to the model "cluster".

The northward shift evident in several global models is likely influenced by a combination of factors.

1) They are picking up on the overall progression and evolution of the pattern, which favors weaker ridging in the W Atlantic from the lower levels to the upper levels
2) They are (again) overestimating the intensity and intensification of Bertha within the short to medium term; intensification of Bertha will likely occur, but the most significant gradual deepening will not occur until the medium to longer range
3) They are not taking the long term movement (faster/just N of due west) of Bertha into account

In regards to the last statement, the current movement of the LLC suggests it will pass very slightly south of the next TPC forecast position. The system looks very unimpressive in terms of organization.

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

Latest ATCF entry indicates west movement as well:

AL, 02, 2008070518, , BEST, 0, 165N, 384W, 45, 1000, TS, 34, NEQ, 75, 30, 0, 75,

[Aric Dunn]

I think most models are still moving here more on a NW or WNW line in the short term....Clearly she is moving more of the DUE WEST right now, (and has been for 12 hours)

agreed

[cheezyWXguy]

The 12z EURO has a strong Bertha just off the coast of New Jersey and Long island.

http://www.ecmwf.int/products/forecasts ... 7091412!!/

haha I remember last night I brought up the possibility of this happening in the chatroom...of course that was for entertainment though

[Hybridstorm_November2001]

It is still VERY far out. However this thing went from near certain fish a few days ago, to a potential long range mainland threat today. Just serves to emphasis (especially for newbies) how unpredictable forecasting in the tropics can often times be.

[ROCK]

>>Definitely the western outlier of all the models. NHC just split the difference. My guess is the UK keeps her so weak that she tracks with the low level flow before stengthening.

I'm waiting to see what the 12z NOGAPS and 12Z ECMWF do in comparison. Btw, what up Rock?

Steve

Hello Steve...long time....crawled out from my under rock (no pun intended) for the season. Should be interesting....

[SouthFloridawx]

The UKMET shift towards the west is due to the lack of intensity with the system. On the last forecast point it has it below tropical storm strength.

Sat Jul 5 16:19:13 EDT 2008



928

WTNT80 EGRR 051731



MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC



AND ATLANTIC



GLOBAL MODEL DATA TIME 12UTC 05.07.2008



TROPICAL STORM BERTHA ANALYSED POSITION : 17.1N 36.3W



ATCF IDENTIFIER : AL022008



VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

12UTC 05.07.2008 17.1N 36.3W MODERATE

00UTC 06.07.2008 17.0N 40.3W MODERATE INTENSIFYING SLIGHTLY

12UTC 06.07.2008 17.4N 44.2W MODERATE WEAKENING SLIGHTLY

00UTC 07.07.2008 18.1N 47.9W MODERATE WEAKENING SLIGHTLY

12UTC 07.07.2008 18.5N 51.5W WEAK WEAKENING SLIGHTLY

00UTC 08.07.2008 18.3N 55.3W WEAK WEAKENING SLIGHTLY

12UTC 08.07.2008 18.9N 58.8W WEAK LITTLE CHANGE

00UTC 09.07.2008 19.2N 62.3W WEAK WEAKENING SLIGHTLY

12UTC 09.07.2008 19.6N 66.1W WEAK LITTLE CHANGE

00UTC 10.07.2008 20.5N 68.9W WEAK LITTLE CHANGE

12UTC 10.07.2008 21.9N 72.2W WEAK LITTLE CHANGE

00UTC 11.07.2008 BELOW TROPICAL STORM STRENGTH

[Nimbus]

Looking at the water vapor imagery things look busier than usual to me, its no wonder they are hedging on the long range forecast.

A second trough scenario would seem like a good bet going with the odds, but the upper air environment is just a little too random to predict right now beyond about 36 hours. Short term we have a weakening system under a strong ridge headed west, thats a no brainer.

I would not be surprised if Bertha went a little south of the forecast track after temporarily poofing, but she has held up fairly well considering the cold SST's. The 17-20 knot forward speed will probably get her back over warmer water before she can dissipate.