[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 262048
TCDAT3

Hurricane Lorenzo Discussion Number  17
NWS National Hurricane Center Miami FL       AL132019
500 PM AST Thu Sep 26 2019

Lorenzo has continued to intensify this afternoon, as the 20 n mi
wide eye has become better defined and the cloud tops in the
eyewall have gotten colder.  Various subjective and objective
satellite intensity estimates are now in the 115-125 kt range, so
the initial intensity is increased to a possibly conservative 120
kt.  The hurricane has excellent outflow in all directions except
to the west, where it is starting to interact with an upper-level
trough.

The hurricane has turned toward the northwest since the last
advisory, with the 12-h average motion now 310/10 kt and the shorter
term motion is even more toward the north.  Lorenzo is approaching a
break in the subtropical ridge caused by a series of mid-latitude
troughs to the northwest of the hurricane, and the track guidance
models remain in excellent agreement that Lorenzo should recurve
through the break during the forecast period.  After 24-36 h, the
guidance has shifted a little more to the right, and this part of
the new track forecast has been nudged a little to the right.

Data from the SHIPS model suggest that Lorenzo will be in an area
of maximum potential intensities of 125-135 kt for the next 3-4
days.  This suggests that the current intensification should end
soon as the actual intensity approaches or reaches those speeds.
Fluctuations in strength due to eyewall replacement cycles are
expected during the 12-24 h period.  The global models suggest that
Lorenzo's interaction with the aforementioned upper-level trough
should increase during recurvature, which should cause increased
shear and a gradual weakening of the cyclone.  As Lorenzo
subsequently moves northeastward in the mid-latitude westerlies,
increased shear and cooler sea surface temperatures should lead to
at least a continued slow weakening.  The new intensity forecast
has only minor changes from the previous forecast.

While its exact ranking will be determined later, Lorenzo is one of
the largest and most powerful hurricanes of record for the central
tropical Atlantic, with the only comparable hurricane in recent
times near there being Gabrielle of 1989.


FORECAST POSITIONS AND MAX WINDS

INIT  26/2100Z 16.5N  40.8W  120 KT 140 MPH
 12H  27/0600Z 17.6N  41.9W  125 KT 145 MPH
 24H  27/1800Z 19.6N  43.0W  120 KT 140 MPH
 36H  28/0600Z 21.3N  43.6W  115 KT 130 MPH
 48H  28/1800Z 22.9N  43.8W  110 KT 125 MPH
 72H  29/1800Z 26.5N  42.3W  100 KT 115 MPH
 96H  30/1800Z 30.5N  39.5W   95 KT 110 MPH
120H  01/1800Z 35.5N  35.0W   90 KT 105 MPH

$$
Forecaster Beven
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