[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 260235
TCDAT3

Hurricane Lorenzo Discussion Number  13
NWS National Hurricane Center Miami FL       AL132019
1100 PM AST Wed Sep 25 2019

A small eye has been intermittently appearing in infrared satellite
imagery over the past few hours, and a recent WINDSAT microwave
overpass showed that the inner-core of Lorenzo is trying to
consolidate. There is still some dry air wrapping in toward the
center of circulation as seen in an SSMIS overpass at 2020 UTC. This
could be the reason why the hurricane has not been able to develop a
well-defined eye as of yet. An ASCAT-B scatterometer pass this
evening showed a still expanding wind field associated with Lorenzo,
and the 50-kt winds now extend up to 90 n mi from the center in the
northern semicircle. A blend of the subjective intensity estimates
from TAFB and SAB support the initial intensity of 85 kt for this
advisory.

Based on the improving inner-core structure, large central dense
overcast, and an expanding cirrus shield around the hurricane, it is
believed that the dry air that has been entrained near the center
will mix out soon. This should allow for the eyewall to completely
develop and Lorenzo should reach major hurricane intensity within
the next 24 hours. Lorenzo will continue over warm waters and in a
light shear environment during the next couple of days, which should
allow for some additional strengthening. By 72 hours, increasing
shear due to west to southwest winds aloft ahead of an approaching
mid-latitude trough should begin to weaken the hurricane. The
official intensity forecast is very near the previous one, and is on
the high end of the guidance through 72 hours.

Lorenzo is moving west-northwest at 13 kt to the south of a
mid-level ridge. The model guidance is in very good agreement on a
break developing in the ridge between 45W-50W in the next couple of
days, which should result in a turn to the northwest. From day 3-5,
the cyclone is expected to turn north then northeast around the
periphery of the mid-level ridge to its east. The official forecast
was nudged just a little to the right of the previous one starting
at 36 h and is on the left side of tightly clustered consensus
guidance.


FORECAST POSITIONS AND MAX WINDS

INIT  26/0300Z 14.7N  38.1W   85 KT 100 MPH
 12H  26/1200Z 15.2N  39.6W   95 KT 110 MPH
 24H  27/0000Z 16.8N  41.2W  105 KT 120 MPH
 36H  27/1200Z 18.5N  42.3W  110 KT 125 MPH
 48H  28/0000Z 20.4N  43.3W  110 KT 125 MPH
 72H  29/0000Z 23.8N  43.9W  105 KT 120 MPH
 96H  30/0000Z 27.5N  42.4W  100 KT 115 MPH
120H  01/0000Z 31.9N  39.1W   95 KT 110 MPH

$$
Forecaster Latto
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