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Tropical Depression FOURTEEN-E


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Tropical Depression Fourteen-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP142019
900 AM MDT Tue Sep 17 2019

Deep convection has intensified over the small area of low pressure
that NHC has been monitoring for several days.  Both SAB and TAFB
estimates indicate that there is now enough organized thunderstorm
activity to initiate advisories on a tropical depression, and the
initial wind speed of 30 kt matches the overnight scatterometer
data and the subjective Dvorak estimates.

The initial motion is an uncertain 335/8 kt, with steering provided
by a distant low-level ridge to the east.  The cyclone is forecast
to gradually turn toward the northwest and west-northwest during the
next several days as it runs into the southwestern side of a mid-
latitude ridge centered over northwestern Mexico. The biggest
complication is Tropical Storm Lorena to the northeast, which some
of the model guidance, such as the 6Z GFS, shows a binary
interaction with at longer term, which could induce a more northward
motion. While I can't rule that out, the forecast will stay closer
to the models that show less interaction, such as the more westward
HWRF and ECMWF solutions, and the NHC forecast is close to a blend
of those models.

While almost all of the guidance indicates strengthening of this
depression into a hurricane in a few days, this forecast is
problematic because of the proximity to Lorena.  Convective outflow
from Lorena could induce more easterly shear than is currently
forecast if the tracks get closer together.  For now, since the
cyclones are forecast to remain a fair distance from one another,
this wind speed prediction assumes that the low-shear environment in
most of the models materializes, and the forecast follows the
corrected-consensus intensity guidance HCCA.

FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 11.9N 108.2W   30 KT  35 MPH
 12H  18/0000Z 12.9N 108.9W   35 KT  40 MPH
 24H  18/1200Z 14.5N 110.2W   45 KT  50 MPH
 36H  19/0000Z 15.7N 111.8W   50 KT  60 MPH
 48H  19/1200Z 16.5N 113.0W   55 KT  65 MPH
 72H  20/1200Z 17.1N 114.1W   70 KT  80 MPH
 96H  21/1200Z 17.3N 115.3W   75 KT  85 MPH
120H  22/1200Z 17.5N 117.0W   60 KT  70 MPH

$$
Forecaster Blake

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