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Tropical Storm Mario Discussion Number 4
NWS National Hurricane Center Miami FL EP142019
300 AM MDT Wed Sep 18 2019
Mario has done well in fighting off northeasterly shear that
continues to impact it, with deep convection extending across the
center for much of the night. A recent scatterometer pass indicated
that tropical storm force winds now extend up to 80 n mi in the
southeast quadrant, and 60 n mi in the northeast quadrant. This pass
also indicated that the maximum winds have increased to 40 kt, and
this will be the initial advisory intensity.
Mario has turned a little to the left, and the initial motion is now
310/09 kt. A mid-level ridge to the northeast of the cyclone should
continue to steer it in this general direction through Thursday
morning. By late Thursday, a trough digging into the western United
States is expected to erode the ridge, and the steering currents
will collapse. This will result in a decrease in forward speed and
eventually Mario is expected to become nearly stationary through
Friday night. By Saturday, the ridge is forecast to rebuild over
Mexico, which would result in Mario beginning a north-northwest
motion. The official forecast track is high confidence through 72
hours and in the middle of tightly clustered consensus guidance.
After 72 hours when the cyclone is expected to begin moving again,
the guidance diverges and has shifted a little to the east. The
official forecast was also shifted a little to the east, but remains
west of the consensus aids during that time frame.
The shear affecting Mario is expected to continue for the duration
of the forecast period, while tropical cyclone Lorena remains to the
northeast. Warm waters and a favorable atmospheric environment
aside from the shear should allow for gradual strengthening for the
next couple of days, and Mario is forecast to become a hurricane by
Friday. By Saturday, Mario will begin to move into a drier and more
stable environment, while the shear remains. This should cause a
weakening trend to begin and continue through the end of the
forecast period. The official forecast is similar to the previous
one, and is on the higher end of the consensus aids.
FORECAST POSITIONS AND MAX WINDS
INIT 18/0900Z 13.7N 110.1W 40 KT 45 MPH
12H 18/1800Z 14.7N 111.0W 45 KT 50 MPH
24H 19/0600Z 15.7N 112.2W 50 KT 60 MPH
36H 19/1800Z 16.4N 112.8W 60 KT 70 MPH
48H 20/0600Z 16.7N 113.0W 65 KT 75 MPH
72H 21/0600Z 17.5N 112.9W 65 KT 75 MPH
96H 22/0600Z 19.0N 113.6W 60 KT 70 MPH
120H 23/0600Z 21.0N 114.5W 55 KT 65 MPH
$$
Forecaster Latto
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