Tropical Storm Bertha Model Runs

[jhamps10]

If the models are to verify, the ridge to Bertha's north had better start breaking down soon. As I gaze at the WV loop, I see the ridge that has been stearing Bertha to the W in lock step with her. Kinda almost looks like Dean and Felix last year. Models kept insisting on breaking down the ridge but it didn't happen. I just can't see Bertha passing to the east of Bermuda like a couple of the models are suggesting this afternoon. I would not be surprised to see a shift to the left in track guidance down the road. Kind of having flashbacks when the NHC insisted on taking Katrina NW when she decided to go SW. Models have a horrible poleward bias that have been there for years with CV hurricanes...Georges, Ivan, ect......MGC

nice post, as I look at the loop I too see the same thing. I'm not saying that Florida, or anywhere in the US is in the threat , but everything I see based off the WV tells me that this ridge may not back down like the models show it to do.

[kpost]

how far west is it in that model, i live at about 28 N and -80.5 even if it did not make land fall could it still effect the barrier islands?

[cpdaman]

if my memory serves me correctly Aric the gfs was a joke w/ intensity of felix and dean but dead on with the track.

Just watched twc update and they were concerned Bertha may be around for a long time, seems like that first trough (the one set to reach east coast in couple days) may not be enough to lift her up AND away, obviously that's a big may and we will have a better idea if the next set of guidance is consistent with the first trough not being enough to take her out to sea (yet) but this does take me up a notch as far as my concern with this storm goes for anyone in the S.E. and perhaps even further north (just still something to keep an eye on)

in conclusion: very interested to see if new batch of model guidance lifts bertha out w/ trough.

[cycloneye]

18z GFDL: It recurves around 62w and then it crawls.

WHXX04 KWBC 062330
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL STORM BERTHA 02L

INITIAL TIME 18Z JUL 6

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 17.7 46.4 280./18.0
6 18.2 48.2 285./17.3
12 18.6 50.0 282./18.3
18 18.9 51.3 286./12.4
24 19.6 52.8 295./15.6
30 20.0 53.8 289./10.4
36 20.5 54.9 294./11.4
42 21.0 55.9 298./10.9
48 21.4 56.7 301./ 8.2
54 21.7 57.6 284./ 9.0
60 22.1 58.4 298./ 8.9
66 22.9 59.0 326./ 9.4
72 23.7 59.7 318./10.4
78 24.7 60.2 333./10.3
84 25.6 60.7 328./10.5
90 26.5 61.2 334./10.2
96 27.5 61.4 349./10.2
102 28.4 61.6 346./ 8.4
108 29.1 62.0 336./ 8.3
114 29.7 62.2 341./ 6.3
120 30.2 62.3 348./ 5.3
126 30.7 62.2 10./ 5.0

[Extremeweatherguy]

how far west is it in that model, i live at about 28 N and -80.5 even if it did not make land fall could it still effect the barrier islands?

In this model run (and keep in mind this is only a single model run and not an official forecast), the storm stalls and drifts in the vicinity of 26-29N and 67-70W. If this run were to be 100% accurate, then your area would likely only experience an increase in wave action from Bertha.

[Nimbus]

Looking at the water vapor imagery it is going to be close. The first trough just to her north which is supposed to provide a little shear is all the way down to 20N but it is not digging very fast that I can see. That is enough of a weakness to set Bertha on a WNW course for a while and provide some ventilation for the outflow.. Looks like once she moves into the ridge on the west side of the trough she may turn back on a more westerly track after tomorrow. The second trough which will not arrive till the end of the week is probably going to dig and take Bertha out but stranger scenarios have happened.

[KWT]

Looks like GFDL starts this system off nearly a full degree in latitude too far south, not that it makes much difference as it still recurves, very close to Bermuda mind you, should miss to the east on that track but it would only take a slightly more westerly track for that to be a threat if the GFDL was right.

[kpost]

how far west is it in that model, i live at about 28 N and -80.5 even if it did not make land fall could it still effect the barrier islands?

In this model run (and keep in mind this is only a single model run and not an official forecast), the storm stalls and drifts in the vicinity of 26-29N and 67-70W. If this run were to be 100% accurate, then your area would likely only experience an increase in wave action from Bertha.

my husband would love that he is hoping for some swell. as long as sunny on all land

[cycloneye]

55kts,994 mbs,moving 285 at 18kts.

WHXX01 KWBC 070040
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0040 UTC MON JUL 7 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) 20080707 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080707 0000 080707 1200 080708 0000 080708 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 18.4N 48.1W 19.4N 51.4W 20.3N 54.1W 21.1N 56.7W
BAMD 18.4N 48.1W 19.5N 50.7W 20.4N 52.5W 21.1N 53.9W
BAMM 18.4N 48.1W 19.2N 51.1W 20.0N 53.5W 20.6N 55.5W
LBAR 18.4N 48.1W 19.5N 51.2W 20.5N 54.0W 21.2N 56.2W
SHIP 55KTS 64KTS 70KTS 74KTS
DSHP 55KTS 64KTS 70KTS 74KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080709 0000 080710 0000 080711 0000 080712 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 22.1N 58.7W 24.5N 63.0W 27.0N 66.2W 28.3N 67.7W
BAMD 21.9N 55.1W 24.0N 57.0W 25.6N 57.8W 25.0N 58.5W
BAMM 21.4N 57.2W 23.6N 60.5W 25.9N 62.9W 26.6N 64.5W
LBAR 22.3N 58.0W 24.6N 61.0W 26.5N 62.5W 27.6N 63.1W
SHIP 76KTS 72KTS 65KTS 67KTS
DSHP 76KTS 72KTS 65KTS 67KTS

...INITIAL CONDITIONS...
LATCUR = 18.4N LONCUR = 48.1W DIRCUR = 285DEG SPDCUR = 18KT
LATM12 = 17.7N LONM12 = 44.4W DIRM12 = 286DEG SPDM12 = 20KT
LATM24 = 16.8N LONM24 = 40.3W
WNDCUR = 55KT RMAXWD = 30NM WNDM12 = 45KT
CENPRS = 994MB OUTPRS = 1012MB OUTRAD = 180NM SDEPTH = D
RD34NE = 75NM RD34SE = 30NM RD34SW = 0NM RD34NW = 75NM

$$

[brunota2003]

Disregard

[HURAKAN]

If I was living in Bermuda I would pay very close atention to the future of Bertha.

[brunota2003]

The BAMD shows it tracking back towards the south at the end of the run (according to the Lat/Long on there)

[cycloneye]

00:00 UTC SHIP Forecast: The most higher shear value is 24kts in 84 hours,but drops after that.

Code: Select all

              *   ATLANTIC SHIPS INTENSITY FORECAST       *
                    *        GOES/OHC INPUT INCLUDED            *
                    *      BERTHA  AL022008  07/07/08  00 UTC   *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    55    60    64    68    70    74    76    74    72    66    65    66    67
V (KT) LAND       55    60    64    68    70    74    76    74    72    66    65    66    67
V (KT) LGE mod    55    59    62    65    67    71    73    74    73    70    67    67    68

SHEAR (KTS)       12     9    10    11    15    17    11    20    20    24     9     4     3
SHEAR DIR        209   227   261   257   248   280   233   260   238   247   242   275   231
SST (C)         26.4  26.7  27.1  27.3  27.5  27.9  27.9  27.9  28.0  27.9  27.7  27.3  26.6
POT. INT. (KT)   120   123   127   128   131   136   135   136   137   136   133   127   118
ADJ. POT. INT.   116   118   120   121   123   126   124   124   125   121   117   109   101
200 MB T (C)   -54.3 -54.5 -54.6 -54.2 -54.4 -54.8 -54.5 -55.0 -54.5 -54.9 -55.1 -55.0 -54.6
TH_E DEV (C)       8     9     9     9    10     9    10     9    10    10    11     9     9
700-500 MB RH     48    47    43    47    47    46    48    49    49    48    44    47    50
GFS VTEX (KT)     12    11    11    13    13    14    13    12    13    11    10    10    10
850 MB ENV VOR    52    46    47    41    22    18     9   -16   -38   -64   -87   -87   -64
200 MB DIV        55    45    29    12     2    10    -1    14    10    -2     1    -8     0
LAND (KM)       1550  1513  1414  1351  1294  1068   904   781   750   808   941  1064  1149
LAT (DEG N)     18.4  18.8  19.2  19.6  20.0  20.6  21.4  22.4  23.8  25.3  26.9  28.4  29.8
LONG(DEG W)     48.1  49.6  51.1  52.3  53.5  55.8  57.7  59.6  61.5  63.2  64.8  65.5  65.6
STM SPEED (KT)    16    15    13    12    12    10    10    11    11    10    10     7     7
HEAT CONTENT       8    17    21    24    29    39    37    33    29    24    19    14     5

  FORECAST TRACK FROM OFCI      INITIAL HEADING/SPEED (DEG/KT):285/ 18      CX,CY: -16/  5
  T-12 MAX WIND:  45            PRESSURE OF STEERING LEVEL (MB):  656  (MEAN=625)
  GOES IR BRIGHTNESS TEMP. STD DEV. 100-300 KM RAD:  14.7 (MEAN=20.0)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  97.0 (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.   2.   2.   3.   4.   4.   4.   5.   4.   3.   1.
  VERTICAL SHEAR         0.   1.   1.   1.   1.   2.   1.   0.  -2.   0.   2.   4.
  PERSISTENCE            2.   3.   4.   4.   5.   5.   4.   4.   3.   2.   1.   0.
  200/250 MB TEMP.       0.   0.   0.   1.   1.   2.   2.   3.   3.   4.   5.   6.
  THETA_E EXCESS         0.   0.   0.  -1.  -1.  -1.  -1.  -2.  -2.  -2.  -3.  -3.
  700-500 MB RH          0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  GFS VORTEX TENDENCY    0.   0.   0.   0.   1.   0.   0.   0.  -2.  -3.  -3.  -3.
  850 MB ENV VORTICITY   0.   0.   0.   0.   0.   0.   0.  -1.  -2.  -3.  -4.  -5.
  200 MB DIVERGENCE      0.   0.   0.   0.   0.   0.  -1.  -1.  -2.  -2.  -2.  -2.
  ZONAL STORM MOTION     0.   0.   1.   1.   2.   3.   4.   5.   5.   6.   7.   8.
  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       4.   7.  11.  13.  17.  20.  20.  19.  14.  14.  14.  14.

  SATELLITE ADJUSTMENTS ----------------------------------------------------------
  MEAN ADJUSTMENT        0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -2.
  GOES IR STD DEV        0.   1.   1.   1.   1.   1.   1.   0.   0.   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.  -1.  -1.  -1.  -1.  -1.  -1.
                        ----------------------------------------------------------
  TOTAL ADJUSTMENT       1.   1.   2.   2.   1.   1.   0.  -2.  -3.  -3.  -3.  -3.
                        ----------------------------------------------------------
  TOTAL CHANGE (KT)      5.   9.  13.  15.  19.  21.  19.  17.  11.  10.  11.  12.

   ** 2008 ATLANTIC RI INDEX AL022008     BERTHA 07/07/08  00 UTC **
           ( 25 KT OR MORE MAX WIND INCREASE IN NEXT 24 HR)
 
 12 HR PERSISTENCE (KT):  10.0 Range:-45.0 to  30.0 Scaled/Wgted Val:  0.7/  1.3
 850-200 MB SHEAR (KT) :  11.3 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.7/  1.2
 D200 (10**7s-1)       :  28.6 Range:-20.0 to 149.0 Scaled/Wgted Val:  0.3/  0.4
 POT = MPI-VMAX (KT)   :  64.5 Range: 25.1 to 130.7 Scaled/Wgted Val:  0.4/  0.4
 850-700 MB REL HUM (%):  64.0 Range: 56.0 to  88.0 Scaled/Wgted Val:  0.2/  0.1
 % area w/pixels <-30 C:  89.0 Range: 17.0 to 100.0 Scaled/Wgted Val:  0.9/  0.2
 STD DEV OF IR BR TEMP :   7.6 Range: 35.1 to   3.2 Scaled/Wgted Val:  0.9/  1.1
 Heat content (KJ/cm2) :  19.8 Range:  0.0 to 132.0 Scaled/Wgted Val:  0.1/  0.0
 
 Prob of RI for 25 kt RI threshold=    24% is   1.9 times the sample mean(12.3%)
 Prob of RI for 30 kt RI threshold=    18% is   2.3 times the sample mean( 7.8%)
 Prob of RI for 35 kt RI threshold=     9% is   1.9 times the sample mean( 4.5%)

   ##         ANNULAR HURRICANE INDEX (AHI) AL022008     BERTHA 07/07/08  00 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

[boca]

LONG TERM...TUESDAY THROUGH SUNDAY...FINALLY, A SIGNIFICANT
CHANGE IN THE WX CONDITIONS ACROSS MAINLAND SOUTH FLORIDA. AS THE
DEEP LAYER RIDGE BUILDS WESTWARD NORTH OF THE LOCAL AREA, NOT ONLY
THE CONVECTIVE PATTERN WILL CHANGE, BUT ALSO DRIER AIR WILL BE
ADVECTED OVER S. FL AND A SLIGHT INCREASE IN M/U SUBSIDENCE IS
EXPECTED. YET, DIURNAL HEATING AND LOCAL SEA/LAKE BREEZES COULD
COMBINE TO INDUCE THE DEVELOPMENT OF AFTERNOON SHWRS/TSTMS. WL
EXPECT THEM TO CONCENTRATE MAINLY OVER WEST COAST/WRN INTERIOR
WITH LESS COVERAGE OVER ERN AREAS

The reason why I post this is because the models have this turning about 65w but the high is building north of S FL. Why would Bertha turn if high pressure is building westward.

[ekal]

A full-latitude trof is not necessary to turn a cyclone. A weakness in the ridge is sufficient, which is expected to be present around 65W.

[CourierPR]

A full-latitude trof is not necessary to turn a cyclone. A weakness in the ridge is sufficient, which is expected to be present around 65W.

I'll believe it when I see it.

[ekal]

A full-latitude trof is not necessary to turn a cyclone. A weakness in the ridge is sufficient, which is expected to be present around 65W.

I'll believe it when I see it.

With all the models projecting a northward turn between 60W and 70W, I will believe a westerly track when I see it.

[Steve]

operational early cycle link for 00z

http://euler.atmos.colostate.edu/~vigh/ ... early1.png

[senorpepr]

operational early cycle link for 00z

http://euler.atmos.colostate.edu/~vigh/ ... early1.png

AHHHHHH OMG!!!!!!!!!!!1
The XTRP Model has it coming straight to Key West!!!!!!!









Sorry... I had to be the first one to say that.
Of course, for those who are playing at home, XTRP is not a model, but rather an extrapolation of the current movement, projected out for five days. It takes no dynamics into play.

[HURAKAN]

XTRP is usually my favorite!!!