000
WTPZ42 KNHC 190231
TCDEP2

TROPICAL STORM LOWELL DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP122014
800 PM PDT MON AUG 18 2014

The cyclone has become slightly better organized over the past
several hours, although the center remains on the northeastern side
of a large area of deep convection.  Dvorak estimates have risen to
35 kt from both TAFB and SAB, so the initial wind speed is raised
to that value.  Lowell has a couple of days to intensify further
while it remains over warm waters with moderate easterly shear.
Only gradual strengthening is anticipated due to the large size of
the system and its large radius of maximum winds.  In a few days,
the storm should traverse cooler waters and begin to slowly weaken.
Model guidance is tightly clustered, and the new NHC intensity
forecast is close to a blend of the previous interpolated forecast
and the latest model consensus.

The storm has turned a little more to the right and is now moving
295/6.  Lowell is expected to move slowly northwestward and then
northward over the next couple of days as it moves into a weakness
in the subtropical ridge caused by an unseasonably strong deep-layer
trough across the U.S. west coast.  Little change was made to the
previous NHC forecast in the first 48 hours with model guidance in
excellent agreement.  The trough should pass the storm by late
Wednesday and then the subtropical ridge is expected to
restrengthen, forcing Lowell to turn to the northwest at an
increasing forward speed after day 3.  Similar to the last forecast
cycle, the guidance has shifted westward at longer range, and the
NHC track prediction is moved in that direction.

A northward surge of moisture into the southwestern United States,
partly caused by the eastern portion of the cyclone's large
circulation, is still forecast by most of the global models to occur
by late Wednesday and Thursday.  Please monitor products issued by
your local National Weather Service office for more details on a
possible heavy rainfall threat.

FORECAST POSITIONS AND MAX WINDS

INIT  19/0300Z 17.0N 118.6W   35 KT  40 MPH
 12H  19/1200Z 17.4N 119.4W   40 KT  45 MPH
 24H  20/0000Z 18.0N 120.0W   45 KT  50 MPH
 36H  20/1200Z 18.6N 120.4W   50 KT  60 MPH
 48H  21/0000Z 19.3N 120.8W   50 KT  60 MPH
 72H  22/0000Z 21.0N 121.9W   45 KT  50 MPH
 96H  23/0000Z 23.4N 124.5W   35 KT  40 MPH
120H  24/0000Z 25.5N 127.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Blake