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Hurricane LORENZO


Hurricane Lorenzo Discussion Number  18
NWS National Hurricane Center Miami FL       AL132019
1100 PM AST Thu Sep 26 2019

Lorenzo has intensified even more this evening, with a clear eye
characterized by warm temperatures of up to 17 degrees
Celsius. The eye is now completely surrounded by a ring of
convection with cold cloud tops less than minus 70 degrees Celsius.
The subjective Dvorak intensity estimates from both TAFB and SAB,
as well as the objective intensity estimate from UW-CIMSS ADT
unanimously support increasing the initial intensity to 125 kt.
Lorenzo is a very large hurricane, with tropical storm force winds
extending over 200 n mi from the center in the northern semicircle,
and a cirrus cloud canopy that spans greater than a 10 degree
latitude by 10 degree longitude area.

The initial motion is now north-northwest, or 330/12 kt. Model
guidance is in very good agreement throughout the 5 day period on
the future track of Lorenzo. The hurricane will move through a break
in the subtropical ridge currently to its northwest over the next
couple of days, gradually turning to the north then northeast as it
rounds the periphery of a ridge to its east. Late in the forecast
period, Lorenzo will begin to accelerate as it gets caught in
southwesterly flow ahead of an approaching mid-latitude trough. The
model guidance made a slight shift to the left since the previous
advisory, but since the same guidance shifted right earlier today, I
did not want to make much of a change to the track. The official
forecast track is very near the previous one, and is now on the
right side of the consensus guidance.

The environment around Lorenzo is expected to change little over
the next day or so. Both dynamical and statistical guidance are
suggesting that the hurricane is nearing peak intensity. Therefore
only fluctuations in strength due to eyewall replacement cycles are
expected through about Friday night. Over the weekend, some moderate
westerly shear ahead of the approaching mid-latitude trough could
begin to slowly weaken the cyclone. Late in the forecast period,
the combination of strong upper level southwesterly winds and
cooler sea surface temperatures should cause a faster weakening
trend. The official forecast is essentially an update of the
previous one, and a little higher than most of the guidance through
the first 48 hours.


INIT  27/0300Z 17.6N  41.5W  125 KT 145 MPH
 12H  27/1200Z 19.1N  42.3W  125 KT 145 MPH
 24H  28/0000Z 21.0N  43.3W  120 KT 140 MPH
 36H  28/1200Z 22.7N  43.8W  115 KT 130 MPH
 48H  29/0000Z 24.4N  43.6W  110 KT 125 MPH
 72H  30/0000Z 27.8N  41.8W  100 KT 115 MPH
 96H  01/0000Z 31.8N  39.0W   95 KT 110 MPH
120H  02/0000Z 37.5N  33.2W   85 KT 100 MPH

Forecaster Latto