Sunday, August 30, 2015

Erika dissipates over eastern Cuba; heavy rain still possible for Florida

Erika dissipates over eastern Cuba; heavy rain still possible for Florida
By Brian McNoldy August 29 at 9:50 AM

Like a broken record, Erika is still very disorganized, and has still
not turned toward the northwest. Since a surface circulation could not
be found by aircraft reconnaissance — the latest best guess of a surface
center is now near the northern coast of Cuba — it no longer qualifies
as a tropical cyclone. But several inches of rain are still possible
across parts of central and southern Florida starting Sunday.

Erika has been forecast to turn toward the northwest for several days
now, and it did not. Only recently did it start to nudge slightly to
the west-northwest. The persistence in track forecasts is illustrated
in the chart below, which shows a series of model consensus track
forecasts overlaid, with the oldest in light blue and the most recent in
dark blue. The red Xs show the actual observed center. The official
National Hurricane Center tracks look nearly identical to these.

With that in mind, below is the 8 a.m. update to the official forecast,
which does notably include a northwest turn today. The funny-looking
curve over Cuba is not a real forecast, it's caused by the 8 a.m.
updated position not agreeing at all with the 5 a.m. forecast track.
Finding the center of such a sloppy system is extremely challenging,
and this morning's update illustrates that. What's left of the center
was repositioned to the north side of Cuba.

The forecast also indicates that Erika could reorganize into a tropical
storm over the eastern Gulf. But the abnormally large uncertainty in
this forecast cannot be overstated. It's a case where the cone needs a
cone! It is absolutely possible that Erika's remnants will never
recover and regenerate.

As the Lesser Antilles, Puerto Rico, Dominican Republic, Haiti, and soon
Cuba can attest to, even a messy weak tropical cyclone or disturbance is
quite capable of producing a LOT of rain. The official intensity of the
storm (tropical depression, Category 1 hurricane, Category 3 hurricane,
etc) is only gauged by the peak wind somewhere in the entire storm, but
other impacts are also destructive and must not be ignored. The latest
5-day precipitation forecast below shows substantial amounts of rain for
basically all of Florida, but particularly along the west coast. This
is by far the biggest anticipated impact from Erika, or what's left of it.

Stay tuned for further updates on Erika and its potential impacts.

Brian McNoldy works in cyclone research at the University of Miami's
world-renowned Rosenstiel School of Marine and Atmospheric Science
(RSMAS). His website hosted at RSMAS is also quite popular during
hurricane season.

Source: Erika dissipates over eastern Cuba; heavy rain still possible
for Florida - The Washington Post -

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