From Wunderblog:
After spending ten days in meteorological limbo-land frustrating forecasters as an “Invest”, 99L finally developed into Tropical Depression Nine,
confirmed a NOAA hurricane hunter aircraft late Sunday afternoon. But
the storm isn’t done perplexing us yet—the model predictions for the
future intensity of the storm remain wildly divergent, even if we now
have growing confidence that this storm will track into the coast of
Florida north of Tampa on Thursday.
Satellite images on Sunday evening showed a steady increase in the intensity and areal coverage of TD 9’s heavy thunderstorms, though Key West radar
showed only a few spiral bands trying to form near the center. The
depression is not likely to organize quickly, as it was dealing with wind shear that was a moderately high 15 - 20 knots. TD 9 was also struggling with dry air, as seen on water vapor satellite imagery. Sea surface temperatures (SSTs) remained favorable for development, though, near 30 - 30.5°C (86 - 87°F)....
... Intensity forecast for TD 9
The SHIPS model
on Sunday afternoon predicted moderately favorable conditions for
intensification, with wind shear falling to a moderate 10 - 15 knots,
Monday through Wednesday. SSTs will be a very warm 30°C (86°F), and
mid-level relative humidity was predicted to be a reasonably moist 65 -
70%. However, the usually reliable European and GFS models showed little
to no development of TD 9 in their latest 12Z Sunday (8 am EDT) runs.
Our best intensity model, the HWRF model, had TD 9 rapidly intensifying
into a strong Category 2 hurricane just before landfall. Other intensity
models like the DSHIPS and LGEM models had TD 9 as a borderline
Category 1 hurricane at landfall. This storm’s history has been to
under-perform....MORE
Here's the Cone of Uncertainty for 9:
