[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 121454
TCDAT4

Tropical Storm Karl Discussion Number   4
NWS National Hurricane Center Miami FL       AL142022
1000 AM CDT Wed Oct 12 2022

Despite the ragged satellite presentation, Karl has slightly
strengthened this morning.  An Air Force Reserve Hurricane Hunter
aircraft investigating the storm found SFMR wind speeds of 37 kt
and a decreased extrapolated minimum central pressure.  Given these
data, the initial intensity was raised to 40 kt on the earlier
intermediate advisory, and it remains at that value for now.

Karl is slowly moving northward at about 3 kt.  A general northward
motion is forecast for the next 12 hours.  Thereafter, a building
ridge over northern Mexico is expected to steer Karl generally
southward until it makes landfall between 60-72 h.  The model
guidance has continued to shift eastward and shows Karl making the
hairpin turn to the right, instead of left as shown in earlier
cycles.  The official track forecast has been shifted rather
significantly to the east in order to remain within the model
guidance envelope.  The NHC track, however, is on the westernmost
edge of the envelope, and should the guidance continue to shift
eastward, further adjustments may be needed in future advisories.
The Tropical Storm Watch has been extended eastward to Frontera,
Mexico to account for the shift in the track forecast.

Based on the satellite appearance, the deep-layer vertical wind
shear over Karl seems to be increasing.  Global model guidance
suggests the shear will continue to increase and possible force
dry mid-level humidities located upshear into the circulation.
Therefore, the official intensity forecast no longer shows
additional strengthening and instead holds Karl at 40 kt for the
next day or so followed by slight weakening before landfall.  The
cyclone is expected to rapidly decay and dissipate once it moves
inland.

Key Messages:

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

2. Tropical storm conditions are possible in the watch area in
Mexico starting on Thursday night or Friday.


FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 21.7N  94.7W   40 KT  45 MPH
 12H  13/0000Z 22.0N  94.8W   40 KT  45 MPH
 24H  13/1200Z 21.6N  94.8W   40 KT  45 MPH
 36H  14/0000Z 20.9N  94.6W   40 KT  45 MPH
 48H  14/1200Z 20.0N  94.5W   35 KT  40 MPH
 60H  15/0000Z 19.1N  94.8W   35 KT  40 MPH
 72H  15/1200Z 18.1N  95.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  16/1200Z...DISSIPATED

$$
Forecaster Bucci/Brown
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