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Tropical Storm Carlotta Discussion Number 11
NWS National Hurricane Center Miami FL EP042018
400 AM CDT Sun Jun 17 2018
The Acapulco Radar from the Mexican Weather Service has been very
useful in diagnosis and tracking Carlotta tonight. Now that a
portion of the circulation is interacting with land, the radar
presentation has deteriorated compared with several hours ago, and
the cloud pattern observed on satellite has become shapeless. The
cyclone is so tiny than even the ASCAT did not completely identified
the cyclone, but at least it measured a few 35-kt wind vectors.
None of the global models acknowledge the presence of Carlotta in
the analysis. Dvorak T-numbers from al agencies are decreasing, and
on this basis, the initial intensity has been lowered to 45 kt.
Since the interaction with land is expected to continue, the NHC
forecast calls for gradual weakening, and this will occur at a
faster rate if the cyclone moves inland within the next 12 to 24
hours as anticipated.
Yesterday, the forecast was for Carlotta to move northeastward or
northward. The steering currents changed slightly tonight, and
instead, the tiny cyclone is now moving toward the northwest at
about 6 kt or faster. The limited available guidance suggests that
this general motion should continue until dissipation in 36 hours or
so. Since the cyclone is not depicted by the global models, the
forecast is highly uncertain.
Given the northwest track, the Government of Mexico has extended the
Tropical Storm Warning westward along the coast. It must be
emphasized that regardless of whether the center moves inland or
continues moving along the coast, the main threat of heavy rainfall
and potential of life-threatening flash floods and mudslides
continue over the southern parts of Guerrero, Oaxaca and Michoacan.
The rainfall threat will be enhanced by moist southwesterly flow
over the southern Sierra Madre mountains of Mexico. For details,
please see products issued by your local weather office.
FORECAST POSITIONS AND MAX WINDS
INIT 17/0900Z 17.0N 100.7W 45 KT 50 MPH
12H 17/1800Z 17.4N 101.3W 35 KT 40 MPH
24H 18/0600Z 17.9N 101.7W 30 KT 35 MPH...INLAND
36H 18/1800Z 18.5N 102.0W 20 KT 25 MPH...POST-TROP/INLAND