TROPICAL STORM KEVIN DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142015
200 AM PDT THU SEP 03 2015
Recent ASCAT data indicate that the cyclone is producing a sizable
area of 35-kt winds, especially beneath a burst of deep convection
which has persisted during the past few hours. The scatterometer
data also indicated that the low-level center is now embedded
beneath the southeastern edge of the convective canopy, and Dvorak
estimates are a consensus T2.5/35 kt from TAFB and SAB. Based on
these data, the cyclone is being upgraded to Tropical Storm Kevin.
Although some southerly shear is expected to continue affecting
Kevin during the next several days, warm sea surface temperatures
and a moist environment could support just a little more
strengthening during the next 24 hours. The NHC intensity forecast
has been adjusted slightly upward during that period and shows a
peak intensity close to the ICON intensity consensus and the Florida
State Superensemble. After 36 hours, the shear is likely to allow
drier air to get into the circulation, leading to weakening. Kevin
is forecast to degenerate to a remnant low by day 3 and dissipate
around day 5.
With the help of the ASCAT data, the low-level center was adjusted
a tad west of where it was previously estimated, and the initial
motion estimate is 350/5 kt. Kevin should continue northward
between a mid-level anticyclone over Mexico and a deep-layer trough
off the west coast of North America for the next 36 hours. Once the
cyclone weakens and is no longer producing significant deep
convection, the center is expected to turn westward in the low-level
flow. The global models appear to be in better agreement on when
this turn will occur, and the bulk of the guidance now shows a
sharper westward turn after 48 hours. The new NHC track forecast is
therefore a bit west of the previous forecast and is close to the
TVCE dynamical consensus.