[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 240237
TCDAT3

Tropical Storm Lorenzo Discussion Number   5
NWS National Hurricane Center Miami FL       AL132019
1100 PM AST Mon Sep 23 2019

Infrared satellite imagery and microwave data indicate that
convection and banding has been on the increase this evening very
near the the center of Lorenzo, while the existing bands that
extend well away from the center have been growing in size.
This improving organization supports raising the initial intensity
to 45 kt, and this is in agreement with the latest subjective Dvorak
estimates from both TAFB and SAB. A recent ASCAT-C overpass
sampled tropical-storm-force winds that now extend up to 80 n
mi in the northern semicircle and suggested that the initial wind
speed could be a little conservative.

Lorenzo will be in an environment favorable for intensification for
the next several days.  And, given the recent increase in convection
near the storm's center, there is now greater confidence that
Lorenzo could become a hurricane by late tomorrow. If the near-term
forecast trend verifies, then it will raise confidence that
Lorenzo may become a major hurricane in the medium range. Only at
the very end of the forecast period does it appear that the system
will begin to encounter increasing shear and some drier air, which
should limit any further strengthening. The official NHC wind speed
prediction shows intensification a little faster than the last
forecast through the first couple of days, but is near the previous
advisory thereafter. This forecast is very close to the HFIP
corrected-consensus HCCA.

Lorenzo is moving westward at 13 kt. A strong mid-level ridge to
the north of the cyclone will steer it generally westward to
west-northwestward over the next few days. Late in the forecast
period, a break in the ridge is forecast to develop between 40-45W,
which should cause Lorenzo to turn to the northwest. The official
NHC forecast is very close to the previous one, and near the
tightly clustered consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 11.6N  26.7W   45 KT  50 MPH
 12H  24/1200Z 12.1N  28.9W   55 KT  65 MPH
 24H  25/0000Z 12.8N  31.5W   65 KT  75 MPH
 36H  25/1200Z 13.4N  34.3W   75 KT  85 MPH
 48H  26/0000Z 14.0N  37.0W   80 KT  90 MPH
 72H  27/0000Z 16.1N  41.3W   90 KT 105 MPH
 96H  28/0000Z 19.0N  44.2W  100 KT 115 MPH
120H  29/0000Z 22.0N  46.0W  100 KT 115 MPH

$$
Forecaster Latto
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