Tropical Storm GABRIELLE (ATL): Global & BAM Models

[TampaFl]

WHXX04 KWBC 041119
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

[b]TROPICAL DEPRESSION INVEST 99L

INITIAL TIME 6Z SEP 4

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 29.6 76.6 115./ 7.0
6 29.3 75.8 108./ 7.3
12 29.2 74.4 95./12.3
18 29.6 72.8 74./14.7
24 30.1 71.7 66./ 9.9
30 31.0 70.7 47./12.7
36 31.6 70.2 42./ 7.1
42 31.6 69.7 86./ 4.4
48 31.7 69.5 67./ 2.0
54 31.7 69.1 90./ 3.7
60 31.7 68.9 85./ .9
66 31.6 69.0 196./ .7
72 31.6 69.4 262./ 4.1
78 31.6 69.6 277./ 1.5
84 32.0 69.9 320./ 4.9
90 32.4 70.4 309./ 5.9
96 33.1 71.0 318./ 8.2
102 33.6 71.8 305./ 8.8
108 34.3 72.2 333./ 7.0
114 35.1 72.4 348./ 8.3
120 36.0 72.3 1./ 8.8
126 36.8 71.9 29./ 9.3
[/b]

http://my.sfwmd.gov/sfwmd/common/images ... r/gfdl.txt
6z GFDL

Cycloneye, is the NHC about to name this a depression? I noticed on the header it says Tropical Depression Invest 99L.

Robert

[canegrl04]

The models don't seem to believe the ridge will build back after the trough passes.Will be interesting to see how they trend over the next few days

[cycloneye]

No,they always have that header in all the invests,but this is not bombing right now for development.

[cycloneye]

867
WHXX01 KWBC 041244
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1244 UTC TUE SEP 4 2007

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 (AL992007) 20070904 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
070904 1200 070905 0000 070905 1200 070906 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 29.4N 75.8W 29.4N 75.7W 29.3N 76.1W 29.0N 76.9W
BAMD 29.4N 75.8W 28.8N 74.2W 29.7N 72.2W 30.8N 71.0W
BAMM 29.4N 75.8W 29.1N 75.1W 29.1N 75.1W 29.1N 75.3W
LBAR 29.4N 75.8W 29.2N 74.5W 29.7N 73.4W 30.8N 72.3W
SHIP 25KTS 29KTS 36KTS 41KTS
DSHP 25KTS 29KTS 36KTS 41KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
070906 1200 070907 1200 070908 1200 070909 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 28.7N 78.6W 28.9N 82.7W 30.1N 85.6W 32.1N 87.4W
BAMD 31.2N 70.1W 31.3N 71.7W 32.0N 74.5W 33.4N 77.0W
BAMM 28.8N 76.0W 28.1N 78.5W 28.0N 80.4W 28.6N 81.9W
LBAR 32.0N 70.5W 34.2N 64.7W 35.9N 59.4W 36.0N 58.0W
SHIP 46KTS 52KTS 54KTS 52KTS
DSHP 46KTS 52KTS 54KTS 31KTS

...INITIAL CONDITIONS...
LATCUR = 29.4N LONCUR = 75.8W DIRCUR = 115DEG SPDCUR = 8KT
LATM12 = 30.0N LONM12 = 77.5W DIRM12 = 114DEG SPDM12 = 7KT
LATM24 = 30.5N LONM24 = 79.0W
WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT
CENPRS = 1009MB OUTPRS = 1014MB OUTRAD = 185NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

$$

[deltadog03]

Here is the EURO.....hurricane going into SC!!!

[LarryWx]

Here are some modeled longitudes as of 12Z Tue 9/4:

1) 12Z MON ECMWF: 77.5 W
2) 12Z MON GEM: 77.0 W
3) 12Z MON NOGAPS: 77.0 W
4) 12Z MON UKMET: 76.5 W
5) 0Z TUE NOGAPS: 76.5 W
6) 0Z TUE GEM: 76.0 W
7) 0Z UKMET: 76.0 W
8) 6Z GFS: 76.0 W
9) 0Z TUE GFS: 75.5 W
10) 18Z MON GFDL 75.5 W
11) 12Z MON GFS: 75.0 W
12) 18Z MON GFS: 75.0 W
13) 0Z TUE GFDL: 75.0 W

The low was initialized at 77.5 W as of the 0Z 9/4 tropical model runs. This seems to be near the current location based on my look at satellite photos. My point is that assuming some continued easterly component of motion between now and 12Z Tue, my feeling is that the 12Z Mon ECMWF/GEM/NOGAPS will very likely and the 12Z Mon UKMET/0Z NOGAPS will quite possibly verify too far west as of 12Z Tue. This would seem to give an early advantage to the further east last three GFS runs, which would appear to lessen the risk to the SE coast below the NC Outer banks at least for now.

Anyone else have any comments on this issue?

Well, using the 12Z Tue BAM suite initialization of 75.8 W for the 12Z Tue position, the bolded model runs in the above list verified the closest. The most west model runs (77.5-77.0 W) are verifying quite a bit too far west and, therefore, have little credibility in my mind.

What does all of this tell me? The overall trend is for a significant reduction in the threat to the SE US outside of the NC Outer banks. The low is moving too far east vs. many of the earlier expectations. The 12Z Mon ECMWF run of a NW hit into GA is very likely way off. Also, although I don't have a 0Z Tue ECMWF position as of 12Z Tue, I'm guessing it is going to verify too far west with its SC hit.

My feeling as of now is for the threat below NC to have reduced significantly. I'm not yet giving the all-clear for those areas in my mind, but I'm getting closer to that point. The greatest U.S. threat imho as of now would be for the NC Outer banks and New England. However, if recent eastward trends continue, the threat for even those areas will drop quite a bit in my mind.

[flwxwatcher]

I don't think the models will have a real good handle on this system until we see for sure where the actual LLC takes shape. Interesting week ahead

[BensonTCwatcher]

Yeah , even split on freak out or get some sleep in the upcoming week. (consensus HAH)

Nonetheless it will be interesting to see which verfies. NOGAPS and Euro, not your typical high confidence combination, but I have to say the euro has been good this year on TC's I know it's a good mid-level model.

[Meso]

12z NAM heh

[Weatherfreak14]

I say this is going to be very intresting for Savannah,GA all the way up the carolinias.

[LarryWx]

I say this is going to be very intresting for Savannah,GA all the way up the carolinias.

Based on recent eastward trends in the low's movement vs. earlier model runs (it is already approaching 75 W), I now think that the threat for all of SC has diminished considerably. I feel that the greatest threat to the SE US is near the NC Outer Banks as of now. If further eastward trends continue, I'll even be reducing the threat in my mind for the Outer Banks as well.

[ericinmia]

I say this is going to be very intresting for Savannah,GA all the way up the carolinias.

Based on recent eastward trends in the low's movement vs. earlier model runs (it is already approaching 75 W), I now think that the threat for all of SC has diminished considerably. I feel that the greatest threat to the SE US is near the NC Outer Banks as of now. If further eastward trends continue, I'll even be reducing the threat in my mind for the Outer Banks as well.

Remember with all storms where steering currents are forecasted to be weak, anything can happen. They don't need to be named but many a storm has done loopty-loops and amazing things. Everyone should continue to watch this for possible development in the event it goes anywhere from central/north florida (storm waits out for a building ridge) to the outer banks (Ridge builds in weaker and storm moves along periphery).

Of course it could simply not develop at all. Or be trapped at see and eventually be persuaded into the graveyard!

P.s. I guess I left it out, but in the most rare case this could end up coming back down to the bahamas/S. Fla. (Stronger ridge pushes the storm further south, and then rides it west/wsw). So technically all on the easter seaboard should be "Bear Watching"

In general the models haven't impressed me much this year, except to some degree the Euro. So I would give that most credence.

[LarryWx]

Now, I'm suddenly starting to wonder if the eastward trend has ceased. The 12Z GFS' 42 hour map has the low a whopping 150 miles SW of the 6Z GFS' 48 hour position fwiw. That's a fairly sig. shift. Let's see if the low ends up a good bit further SW of its 6Z GFS track.

[LarryWx]

The 12Z GFS 84 hour position is a whopping ~300 miles WSW of the 6Z GFS 90 hour and ~100 miles west of the 0Z GFS 96 hour position. Is this the start of a westward model shift??

[caneman]

Larrywx,
Daggumit you just made me choke on my Ham sandwich.

[x-y-no]

12Z GFS takes it inland into South Carolina on day 5.

[vacanechaser]

12Z GFS takes it inland into South Carolina on day 5.

nope... takes inland just south of hatteras... .... right over the outer banx with the eastern eyewall right over hatteras..







Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team

[ronjon]

The BAMs and NOGAPs are showing about a 7 degree longitude move toward the west starting in about 48 hrs. The key is how far this system moves east and/or south between now and then - if it stays around 75W then the entire east coast from FL to Hatteras could be in the cyclone LF zone.

[x-y-no]

Sorry - you're right. I was being lazy and just glancing at the small 4 panel view ...

Day 6 it's sweeping up the coast towards Cape Cod ... nasty scenario if it's a storm of any strength.

[vacanechaser]

The BAMs and NOGAPs are showing about a 7 degree longitude move toward the west starting in about 48 hrs. The key is how far this system moves east and/or south between now and then - if it stays around 75W then the entire east coast from FL to Hatteras could be in the cyclone LF zone.

it seems to be stationary right now... could be a slightward drift, but in the visible seems to be stationary to me




Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team