00z Tropical Guidance vs. reality ...

[Stormsfury]

This thread for comparisons and some verifications of the 00z tropical model guidance vs. the future 9/9/04 8 am advisory ...

Ivan will eventually turn NW ... but NOT so soon ... Ivan has tracked continually further SOUTH than guidance suggests and short term errors of 20-30 Statute miles has HUGE implications down the road ... furthermore, between the 8 pm and 11 pm advisory, Ivan is estimated to have moved 0.2ºN, 0.7ºW ... (13.6ºN, 69.1ºW at 11 am ) ... BASED on that current rate, by 8 am - 14.2ºN, 71.2ºW ... from the SOUTHERNMOST tropical model, it'll be off by 18 miles to the closest, to as much as 0.7º latitude SOUTH of the 14.9ºN, 71.2ºW depicted by the LBAR ... which is 42 STATUTE MILES only 12 hours out!) ...

Code: Select all

HURRICANE IVAN       (AL092004) ON 20040909  0000 UTC

          ...00 HRS...   ...12 HRS...   ...24 HRS...   ...36 HRS...
          040909  0000   040909  1200   040910  0000   040910  1200

           LAT    LON     LAT    LON     LAT    LON     LAT    LON
  BAMD    13.4N  68.4W   14.7N  70.9W   16.1N  73.2W   17.0N  74.9W
  BAMM    13.4N  68.4W   14.5N  70.8W   15.6N  72.7W   16.4N  74.1W
  A98E    13.4N  68.4W   14.5N  71.1W   15.7N  73.6W   16.7N  76.0W
  LBAR    13.4N  68.4W   14.9N  71.2W   16.6N  73.7W   17.9N  76.0W
  SHIP       125KTS         122KTS         117KTS         116KTS
  DSHP       125KTS         122KTS         117KTS         116KTS

          ...48 HRS...   ...72 HRS...   ...96 HRS...   ..120 HRS...
          040911  0000   040912  0000   040913  0000   040914  0000

           LAT    LON     LAT    LON     LAT    LON     LAT    LON
  BAMD    17.7N  76.1W   18.6N  77.6W   20.0N  78.9W   21.7N  79.8W
  BAMM    17.2N  74.8W   19.3N  75.4W   22.6N  75.7W   26.2N  74.4W
  A98E    16.9N  78.0W   17.9N  80.2W   18.8N  81.0W   20.5N  80.1W
  LBAR    18.7N  77.9W   19.9N  80.5W   21.7N  81.2W   24.6N  80.3W
  SHIP       120KTS         124KTS         126KTS         112KTS
  DSHP        85KTS          89KTS          76KTS          62KTS

               ...INITIAL CONDITIONS...
  LATCUR =  13.4N LONCUR =  68.4W DIRCUR = 290DEG SPDCUR =  15KT
  LATM12 =  12.5N LONM12 =  65.5W DIRM12 = 286DEG SPDM12 =  15KT
  LATM24 =  12.0N LONM24 =  62.6W
  WNDCUR =  125KT RMAXWD =   10NM WNDM12 =  120KT
  CENPRS =  938MB OUTPRS = 1008MB OUTRAD =  200NM SDEPTH =   D
  RD34NE =  140NM RD34SE =  125NM RD34SW =   75NM RD34NW = 140NM

The ridge bumped up in the wake of Frances offshore of South Carolina (extension of the large N ATL high) has generally built westward over Florida, and continues to build westward towards the EC of the US ... look at water vapor loops for what I mean, and ...

http://www.ssd.noaa.gov/PS/TROP/DATA/RT/watl-wv-loop.html

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/movies/wg8dlm5/wg8dlm5java.html

[donsutherland1]

Great discussion, SF. I strongly agree with you and believe that Ivan will ultimately move into the Gulf of Mexico rather than escape out to sea as per the GFS and BAMM.

[Ixolib]

Does that mean, in laymen's terms, that the building ridge will hold ivan off the W. coast of FL more than the models are showing?

[Stormsfury]

Ivan went almost DUE WEST for 6½ hours and that IVAN again went SOUTH of the 00z model progs and the error ended up being with the least the A98E, and BAMM with 20 NM to LBAR of nearly 50 NM ... in 12 hours ... on the 00z Guidance

The observations from 5 am to 11 am also show a track near 290° and that's west-northwest:

5 am: 13.9N 70.0W
8 am: 14.2N 70.7W
11 am: 14.5N 71.4W

I was expecting that Ivan would cross 71ºW at 14.1ºN, and in reality, it crossed roughly around 14.3ºN ... not bad in a 12 hour time frame ...

[dhweather]

In the WV loop, around 65/25, it looks like the ridge is meeting the outflow from Ivan, and I'm beginning to think the rdige will continue to push him West, much more than forecast.