[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 140846
TCDAT4

Tropical Storm Karl Discussion Number  12
NWS National Hurricane Center Miami FL       AL142022
400 AM CDT Fri Oct 14 2022

Satellite imagery indicates that Karl remains disorganized this
morning, with the low-level center at the northwestern edge of a
newly-formed convective burst.  Recent scatterometer data and
earlier data from an Air Force Reserve Hurricane Hunter aircraft
did not conclusively indicate any tropical-storm force winds in the
system.  However, the central pressure was near 1001 mb, and based
on likely undersampling of the winds the initial intensity is set
at 35 kt.

The initial motion is southeastward or 140/5 kt. Karl should turn
southward later today and then south-southwestward by tonight as
the system reaches the periphery of a mid-level ridge over
west-central Mexico. This south-southwestward motion is expected to
continue until Karl dissipates over Mexico between 36-48 h.  While
the forecast track follows the consensus models and has not changed
much from the previous advisory, it should be noted that the GFS is
an outlier in that it turns a weak and vertically shallow Karl more
westward and keeps it offshore through 48 h.

Moderate west-northwesterly shear, dry air entrainment, and
upper-level convergence affecting Karl should continue through
landfall.  Thus, little change in strength is likely before
landfall, although it cannot be ruled out that Karl could weaken to
a depression before reaching the coast.  After landfall, the
cyclone should quickly weaken and dissipate between 36-48 h.  Even,
if the cyclone stays over water longer as suggested by the GFS, the
generally hostile environment should not allow strengthening.


Key Messages:

1. Heavy rainfall associated with Karl could produce instances of
flash flooding, with mudslides in areas of higher terrain, across
portions of Veracruz, Tabasco, Chiapas and Oaxaca states in Mexico.

2. Tropical storm conditions are expected to begin within a portion
of the warning area in southern Mexico by late today or tonight.


FORECAST POSITIONS AND MAX WINDS

INIT  14/0900Z 20.2N  92.4W   35 KT  40 MPH
 12H  14/1800Z 19.5N  92.4W   35 KT  40 MPH
 24H  15/0600Z 18.6N  92.8W   35 KT  40 MPH
 36H  15/1800Z 17.7N  93.4W   25 KT  30 MPH...INLAND
 48H  16/0600Z...DISSIPATED

$$
Forecaster Beven
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