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TROPICAL DEPRESSION TWO-E DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
1000 PM CDT SUN MAY 31 2015
The cloud pattern of the depression has not changed much during the
past few hours. The center, a tight swirl of low clouds, has
disappeared underneath new convective growth and a veil of cirrus
clouds. Deep convection is primarily confined to the southeastern
semicircle of the depression's circulation, indicative of strong
northwesterly shear associated with strong outflow of Hurricane
Andres. Satellite intensity estimates are T2.0 and T1.5 from TAFB
and SAB, respectively, so the initial intensity is kept at 30 kt.
The initial motion is a somewhat uncertain 300/04. A mid-level
ridge over Central America should give the depression a push toward
the west-northwest during the next 24 hours. An erratic motion with
a turn toward the south or south-southeast is expected between 24
and 72 hours, when the depression reaches a col area and then is
caught up in the weak flow around a mid-level anticyclone to its
west. After this time, global models show a trough arriving along
the U.S. West Coast, which causes a ridge over Baja California to
shift eastward into northern Mexico. This change in the steering
flow should result in a northwestward motion at a faster forward
speed toward the end of the forecast period. The NHC track forecast
has not changed much over the first 72 hours but is adjusted to the
right after 96 hours to be in better agreement with the multi-model
consensus (TVCE).
Moderate to strong northwesterly shear over the depression should
continue during the next 24 hours, but the shear appears to be
confined to the upper troposphere and not over a deep enough layer
to prevent slow intensification. Model guidance is unanimous in
showing the the shear diminishing to very low values by 36 to 48
hours. The more conducive upper-level winds, combined with very warm
sea surface temperatures of around 30 deg C as well as a very moist
and unstable environment, favor a substantial intensification after
48 hours. The NHC intensity forecast is increased to nearly match
the SHIPS model output, at the upper end of the intensity guidance,
and shows the cyclone reaching major hurricane status in 4 days.
Some increase in easterly shear late in the period is possible, and
the intensity forecast is therefore leveled off after 96 hours.
FORECAST POSITIONS AND MAX WINDS
INIT 01/0300Z 12.7N 103.3W 30 KT 35 MPH
12H 01/1200Z 13.1N 103.9W 35 KT 40 MPH
24H 02/0000Z 13.4N 104.2W 40 KT 45 MPH
36H 02/1200Z 13.2N 104.4W 50 KT 60 MPH
48H 03/0000Z 12.6N 104.2W 65 KT 75 MPH
72H 04/0000Z 12.2N 104.0W 90 KT 105 MPH
96H 05/0000Z 13.5N 105.1W 105 KT 120 MPH
120H 06/0000Z 16.2N 107.7W 105 KT 120 MPH
$$
Forecaster Kimberlain
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