[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 050236
TCDAT3

Tropical Depression Cristobal Discussion Number  14
NWS National Hurricane Center Miami FL       AL032020
1000 PM CDT Thu Jun 04 2020

Cristobal is not very well organized at the moment as the
center of the circulation remains inland over northern Guatemala
and southeastern Mexico.  Satellite images and radar data from
Sabancuy, Mexico, indicate that the associated showers and
thunderstorms lack banding features and the center is becoming
less distinct.  The initial intensity is held at 30 kt, but these
winds are likely occurring over water well to the north and east of
the center.

The depression is moving slowly to the east as it nears the
completion of a cyclonic loop around the Central American gyre that
it has been embedded within.  The models show the depression turning
northward soon on the west side of a subtropical ridge over the
western Atlantic.  This should take Cristobal back over the southern
Gulf of Mexico waters by Friday night, and across the central and
northern Gulf of Mexico over the weekend.  A fairly progressive
ridge moving across the central U.S. could cause Cristobal to turn
to the left slightly as it moves across the Gulf coast late this
weekend and early next week. There remains a fair amount of spread
in the model solutions, with the GFS being the fastest and farthest
east and the ECMWF much slower and to the west.  The NHC track
forecast is between those scenarios and lies near the various
consensus aids, which typically have the lowest errors.

Cristobal is forecast to remain inland for another 12 to 24 hours,
so little change in strength is anticipated during that time.  After
the system moves back over water, gradual strengthening seems likely
until Cristobal reaches the northern Gulf coast.  The
intensification rate should be slow since Cristobal is a large
system and will be moving into an environment of moderate wind shear
and some dry air.  The NHC intensity forecast is largely an update
from earlier and lies roughly near the middle of the guidance
envelope.

Cristobal is expected to have a broad and asymmetric wind field as
it approaches the northern Gulf coast.  Given the expected
environmental conditions, the strongest winds, highest storm surge,
and heaviest rains could be well removed from the center of
circulation.  Therefore, it is important that users do not focus on
the exact forecast path of the center of the cyclone.  For more
information on the potential impacts, see the Key Messages below.

Key Messages:

1. Damaging and deadly flooding has already been occurring in
portions of Mexico and Central America.  Cristobal is expected to
produce additional extreme rainfall amounts through the end of the
week.  The heaviest additional rainfall is expected over far
southern Mexico and portions of the Yucatan Peninsula, while also
extending along the Pacific coast from Chiapas to Guatemala and El
Salvador.  This rainfall could cause widespread life-threatening
flash floods and mudslides. Refer to products from your local
weather office for more information.

2. Cristobal is forecast to re-emerge over the southern Gulf of
Mexico on Friday and move northward over the central and northern
Gulf of Mexico over the weekend.  There is a risk of tropical storm
force winds this weekend from Louisiana to the western Florida
Panhandle and a risk of dangerous storm surge from Louisiana to the
Florida Big Bend. These hazards will arrive well in advance of and
extend well east of Cristobal's center.  Storm surge and tropical
storm watches will likely be issued for a portion of the U.S. Gulf
Coast on Friday.

3. Heavy rainfall will spread into portions of the Gulf Coast from
east Texas to Florida this weekend into early next week, with areas
of flash flooding possible.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 17.8N  90.4W   30 KT  35 MPH...INLAND
 12H  05/1200Z 19.1N  90.1W   25 KT  30 MPH...INLAND
 24H  06/0000Z 20.9N  90.2W   30 KT  35 MPH...NEAR THE COAST
 36H  06/1200Z 22.5N  90.6W   40 KT  45 MPH...OVER WATER
 48H  07/0000Z 24.3N  90.5W   45 KT  50 MPH...OVER WATER
 60H  07/1200Z 26.3N  90.4W   50 KT  60 MPH...OVER WATER
 72H  08/0000Z 28.3N  90.9W   50 KT  60 MPH...OVER WATER
 96H  09/0000Z 32.6N  92.7W   30 KT  35 MPH...INLAND
120H  10/0000Z 37.3N  90.8W   25 KT  30 MPH...INLAND

$$
Forecaster Cangialosi
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