[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 261003
TCDAT3

Hurricane Lorenzo Special Discussion Number  15
NWS National Hurricane Center Miami FL       AL132019
600 AM AST Thu Sep 26 2019

Shortly after the issuance of the 0900 UTC advisory, Lorenzo's eye
quickly and drastically became more apparent in conventional
satellite imagery. The slightly ragged but clearing eye of the
hurricane is surrounded by very cold cloud tops, and it has become
clear that Lorenzo is rapidly intensifying. A 0900 UTC TAFB Dvorak
classification of 6.0/6.0 (115 kt) was used as the primary basis for
increasing the intensity of Lorenzo. Because objective fixes from
just a few hours ago were much lower, the intensity of the hurricane
has been increased, perhaps conservatively, to 110 kt. Since this is
10 kt above the previous 12-h forecast, a special advisory is
required to update the intensity forecast.

Additional strengthening is possible later today. Earlier intensity
guidance indicated that Lorenzo's intensity should level off in a
day or so, though none of the guidance correctly anticipated the
rate at which the hurricane has strengthened this morning. Now that
the hurricane has a closed eyewall, fluctuations in intensity due to
eyewall replacement cycles are also possible, though this is not
explicitly reflected in the updated forecast. By the end of the
forecast period, the updated NHC forecast is relaxed to the original
forecast and shows some gradual weakening. Further adjustments,
especially at 72 h and beyond, may be required later this morning.

No changes were made to the track forecast, which is based on the
previous regular advisory.

FORECAST POSITIONS AND MAX WINDS

INIT  26/1000Z 15.2N  39.3W  110 KT 125 MPH
 12H  26/1800Z 16.0N  40.6W  120 KT 140 MPH
 24H  27/0600Z 17.7N  41.9W  120 KT 140 MPH
 36H  27/1800Z 19.5N  43.0W  115 KT 130 MPH
 48H  28/0600Z 21.2N  43.8W  110 KT 125 MPH
 72H  29/0600Z 24.6N  43.5W  100 KT 115 MPH
 96H  30/0600Z 28.0N  42.0W  100 KT 115 MPH
120H  01/0600Z 33.0N  38.0W   95 KT 110 MPH

$$
Forecaster Zelinsky
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