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Tropical Storm COSME


Tropical Storm Cosme Discussion Number   4...Corrected
NWS National Hurricane Center Miami FL       EP032019
200 AM PDT Sun Jul 07 2019

Corrected to show dissipated at 10/0600Z

Dry air appears to be taking its toll on Cosme. Deep convection
mostly dissipated earlier tonight and water vapor imagery shows very
dry air impinging on the northwestern side of the cyclone, and
wrapping into the southern semicircle of the circulation. There has
been some new convection developing about 100 n mi northeast of the
center over the past few hours, which is likely associated
with the approaching diurnal convective maximum time period. A
recent scatterometer pass that partially captured Cosme's wind field
indicated weakening had occurred over the western portion of the
cyclone over the past several hours which suggests that an overall
weakening trend has begun. Therefore the initial intensity has been
lowered to 35 kt and this is in agreement with the latest TAFB and
ADT satellite intensity estimates.

Cosme will continue to battle dry air while moving over marginally
favorable SSTs today. There is a chance for the regenerating
convection to expand toward the cyclone's center over the next
several hours, thus prolonging the time Cosme will remain a tropical
storm. However, later today the cyclone will begin to cross the 26 C
isotherm and also will enter an even drier environment. This should
cause Cosme to weaken to a tropical depression. Thereafter, the dry
air and cooler SSTs will cause Cosme to become devoid of deep
convection and the cyclone should degenerate into a remnant low
either by tonight, or on Monday. The latest official intensity
forecast shows a weakening trend that is a little faster than
previously forecast, and is in agreement with the latest intensity
guidance as well as model simulated satellite imagery.

Cosme continues on a generally west-northwest track, and has slowed
slightly to around 9 kt. The cyclone will be steered toward a
weakness in the subtropical ridge developing to its northwest over
the next couple of days while gradually decreasing in forward
speed. The latest track guidance is close to the previous forecast
and near the consensus aids.


INIT  07/0900Z 16.9N 118.0W   35 KT  40 MPH
 12H  07/1800Z 17.6N 119.1W   30 KT  35 MPH
 24H  08/0600Z 18.4N 120.3W   25 KT  30 MPH
 36H  08/1800Z 19.1N 121.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  09/0600Z 19.7N 121.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  10/0600Z...DISSIPATED

Forecaster Latto/Pasch