ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM
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
NNNN