000
WTPZ42 KNHC 191435
TCDEP2

TROPICAL STORM LOWELL DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP122014
800 AM PDT TUE AUG 19 2014

The structure of Lowell has not changed much over the past few
hours, with most of the deep convection located south and southeast
of the center. The initial intensity remains 45 kt based on the
earlier ASCAT pass, which is also in agreement with the latest
Dvorak classification from TAFB. Some strengthening is forecast in
the short term, as Lowell will be in an environment of moderate
vertical shear and over warm waters. After that time, Lowell will
be moving over cooler waters and into a drier and more stable
airmass, which should result in steady weakening to remnant low
status by the end of the forecast period. The NHC intensity
forecast is similar to the previous one and is close to the latest
IVCN intensity consensus.

There is a fair bit of spread in the satellite fixes, which is not
surprising given the sprawling structure of the circulation. The
initial motion estimate of 300/06 is based on a blend of the fixes
and continuity from the previous advisory. The track forecast
reasoning remains unchanged. The subtropical ridge currently
steering Lowell will weaken as a shortwave trough digs southward
along the California coast in the next 24 to 36 hours. After that
time, some ridging rebuilds to the north, which should turn a
weakening Lowell back toward the west-northwest by the end of the
period. The new NHC track forecast is similar to the previous one
and close to the TVCE consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  19/1500Z 17.7N 119.7W   45 KT  50 MPH
 12H  20/0000Z 18.2N 120.5W   50 KT  60 MPH
 24H  20/1200Z 18.8N 121.0W   55 KT  65 MPH
 36H  21/0000Z 19.4N 121.3W   55 KT  65 MPH
 48H  21/1200Z 20.1N 121.8W   55 KT  65 MPH
 72H  22/1200Z 22.5N 124.0W   50 KT  60 MPH
 96H  23/1200Z 25.0N 127.0W   40 KT  45 MPH
120H  24/1200Z 26.5N 130.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan