On 25/06/2012 20:22, Liam Steele wrote:
I've been looking at the forecast for TS Debby over the past few days,
and it's interesting how the forecast has changed.

After gaining TS status, Debby was predicted to move westwards towards
Texas, eventually reaching hurricane-strength. This track was
subsequently altered over the next few days, and when I looked yesterday
Debby was instead predicted to move northwards towards Alabama. I've
just looked now, and the track has changed to eastwards, moving over
Florida.

Does anyone know what the problems have been in predicting this storm
track? I know from previous years that paths are constantly amended, but
I can't recall seeing one turn in the complete opposite direction before
(though admittedly I have only been viewing the path predictions for a
short while).


.... Yes, it's been a real 'wanderer' hasn't it!

If you look through the various issues of the 'Discussions', you can see
the hair-tearing-out that's going on in Miami ....

http://www.nhc.noaa.gov/archive/2012.../175401.shtml?

It looks, to try and answer your question, that the problem lies with
the actual behaviour and model prognoses of various upper air features
(which govern the broader steering flow adjacent to the T/S) which vary
from run-to-run within one model, and equally frustrating, vary between
the various models. And of course the T/S itself has some influence on
the environment within which it is being steered ... and there are
doubts about the activity which feed back etc.

Incidentally, if this thing manages to slip across to the south of the
Panhandle, it is forecast by some models to really wind up ....

Martin.


--
West Moors / East Dorset
Lat: 50deg 49.25'N, Long: 01deg 53.05'W
Height (amsl): 17 m (56 feet)
COL category: C1 overall