[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 131443
TCDAT4

Tropical Storm Karl Discussion Number   9
NWS National Hurricane Center Miami FL       AL142022
1000 AM CDT Thu Oct 13 2022

A burst of deep convection has developed over the southeastern
portion of Karl's circulation since the previous advisory. Data from
an Air Force Reserve reconnaissance aircraft and NOAA buoy 42055
indicate that the low-level center of the tropical cyclone is
located near the northeastern edge of that convection due to
northwesterly vertical wind shear.  Although the aircraft has only
measured flight-level and SFMR winds to support an intensity of
around 40 kt, the advisory wind speed is maintained at 45 kt due to
the recent increase in convection. Also, this gives the plane more
time to fully examine the cyclone, as it is possible the strongest
winds have yet to be sampled. Continued northwesterly shear and the
entrainment of dry mid-level air are likely to cause some weakening
over the next day or so, but Karl is forecast to be a tropical storm
when it nears the coast of Mexico.  After landfall, rapid weakening
and dissipation of the low-level circulation is expected as the
cyclone moves over the mountainous terrain of southern Mexico.

Fixes from the aircraft show that Karl has finally begun its
anticipated south-southeastward turn, and the initial motion
estimate is 155/4 kt. A mid-level ridge to the northwest of Karl is
expected to steer the storm south-southeastward through tonight. A
southward to south-southwestward motion is forecast on Friday which
should bring the center of Karl to the Bay of Campeche coast Friday
night or Saturday.  The guidance envelope has moved slightly
eastward this cycle, and the NHC track forecast has been adjusted in
that direction.  There is still some spread in the models as to how
fast Karl will move southward, which results in some timing
differences regarding landfall in Mexico.  The official forecast is
close to the GFEX and the other consensus aids to account for that.

Based on the latest forecast, the government of Mexico has issued a
Tropical Storm Warning for a portion of the coast of the Bay of
Campeche.

Key Messages:

1. Heavy rainfall associated with Karl could produce 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 Mexico by late Friday.

FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 21.7N  93.9W   45 KT  50 MPH
 12H  14/0000Z 21.0N  93.6W   40 KT  45 MPH
 24H  14/1200Z 20.0N  93.3W   40 KT  45 MPH
 36H  15/0000Z 19.1N  93.4W   40 KT  45 MPH
 48H  15/1200Z 18.0N  94.3W   35 KT  40 MPH...INLAND
 60H  16/0000Z 17.0N  95.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  16/1200Z...DISSIPATED

$$
Forecaster Brown
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