A quickie lesson on ridge strength prediction!

[TPACane04]

from NHC Ivan discussion on 9/09 (a week before Ivan hit, while he was still in Caribbean) and models try to bring Ivan up to FL west coast.

THE INITIAL MOTION IS NOW 300/11. THERE IS HIGH CONFIDENCE IN THE FIRST 36-48 HR OF THE FORECAST TRACK...AS THE SUBTROPICAL RIDGE TO THE NORTHEAST OF IVAN SHOULD STEER IT GENERALLY WEST-NORTHWESTWARD.
CONFIDENCE DIMINISHES BEYOND THAT TIME AS THE RIDGE WEAKENS DUE TO AN UPPER-LEVEL TROUGH OVER THE EASTERN UNITED STATES AND AN UPPER-LEVEL LOW OVER THE ATLANTIC CURRENTLY NEAR 31N52W. ALL GUIDANCE AGREES ON A TURN TOWARD THE NORTH...WITH DIFFERENCES ON HOW FAR EAST THAT TURN WILL OCCUR. THE GFS WEAKENS THE RIDGE THE MOST AND BRINGS IVAN NORTHWARD THROUGH THE FLORIDA PENINSULA. THE
UKMET AND NOGAPS KEEP MORE RIDGING NORTH OF IVAN AND THUS KEEP A MORE NORTH-NORTHWESTWARD MOTION. THE NOGAPS AND GFS HAVE BOTH SHIFTED A LITTLE TO THE LEFT...WHILE THE GFDL HAS SHIFTED TO THE RIGHT.

Point: GFS and GFDL did very poorly on ridge strength..and UKMET and NOGAPS had some clue as to it's strength by virtue of poitning him more west, which is where he ultimately headed.

NOW..how this applies to us today remains to be seen..but if Jeanne stays westbound under the ridge, perhaps NOGAPS will show that it is best at indicating ridge strentgh tendency.

[Cookiely]

Maybe something good can come from this terrible season. Perhaps your right and they will realize which models are consistent in certain areas and time frames.