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Tropical Storm Lowell Discussion Number   6
NWS National Hurricane Center Miami FL       EP172020
900 PM MDT Mon Sep 21 2020
 
Lowell's satellite presentation has changed little during the past 
several hours.  Lowell remains a sheared tropical cyclone with a 
few new bursts of deep convection evident to the west of the rather 
poorly defined and exposed surface circulation center.  The initial 
intensity is held at 40 kt for this advisory and is in best 
agreement with the various subjective and objective satellite 
intensity estimates. 
 
Modest northeasterly shear is still impinging over the eastern half 
of the cyclone and this inhibiting factor should relax within the 
next 12 hours or so.  As a result, Lowell should strengthen with 
time through the 48 to 60 hour period as the cyclone traverses warm 
water and continues moving within a moist surrounding environment.  
Through the remaining portion of the forecast, Lowell is expected to 
enter a more stable and drier marine layer which should cause the 
cyclone to gradual weaken.  The NHC intensity forecast is close to 
the NOAA HCCA consensus and the Decay SHIPS, and above the LGEM 
which indicates very little change in strength during the next 5 
days.
 
The initial motion is estimated to be westward, or 280/11 kt.
Low- to mid tropospheric easterly flow produced by a subtropical
ridge anchored to the north of Lowell should steer it in a
generally west-northwestward motion through Wednesday night.  
Around the 60 hour period, a turn back toward the west is expected 
as the aforementioned ridge builds farther west.  The official 
forecast is basically an update of the previous advisory and is 
close to the HFIP Corrected Consensus Approach model.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 17.7N 114.5W   40 KT  45 MPH
 12H  22/1200Z 18.4N 116.2W   45 KT  50 MPH
 24H  23/0000Z 19.0N 118.3W   50 KT  60 MPH
 36H  23/1200Z 19.5N 120.1W   55 KT  65 MPH
 48H  24/0000Z 19.9N 121.8W   60 KT  70 MPH
 60H  24/1200Z 20.0N 123.4W   60 KT  70 MPH
 72H  25/0000Z 20.0N 125.0W   60 KT  70 MPH
 96H  26/0000Z 20.0N 128.4W   55 KT  65 MPH
120H  27/0000Z 20.1N 131.8W   45 KT  50 MPH
 
$$
Forecaster Roberts
 
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