簽到天數: 2141 天 [LV.Master]伴壇終老
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周子堯@FB|2020-8-26 17:35
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NHC於稍早升格TD-13E,首報預估有短暫成為TS的機會
468
WTPZ43 KNHC 260849
TCDEP3
Tropical Depression Thirteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP132020
300 AM MDT Wed Aug 26 2020
The broad area of low pressure that the NHC has been tracking the
past few days has become better defined based on a 0356Z ASCAT-B
scatterometer overpass. Although the system is slightly elongated
northeast-to-southwest, the center is well defined and deep
convection has persisted west of the center despite strong easterly
vertical wind shear of 25-30 kt. Thus, the low has been upgraded to
Tropical Depression 13-E. The initial intensity of 30 kt is based
on scatterometer surface wind speeds of 30-32 kt, which are
consistent with T2.0/30-kt satellite classifications from TAFB-SAB.
The initial motion estimate is slowly north-northeastward or 025/04
kt. The depression is embedded within an east-to-west oriented
cyclonic gyre with a high-amplitude mid-level ridge located over
the southwestern U.S. and northern Mexico. These gyre will cause the
cyclone to move slowly northward today and northwestward on
Thursday, with the ridge acting as a poleward block and forcing to
system to turn west-northwestward to westward on Friday and
Saturday. On the forecast track, the cyclone is expected to remain
just offshore the southwestern coast of Mexico today and Thursday,
and pass near or just south of the southern tip of Baja California
Sur on Friday and Saturday. The NHC official track forecast closely
follows the simple consensus model TVCE, and lies a little to
the left or west of the corrected-consensus model HCCA and the
ECMWF model tracks.
Strong easterly shear is forecast to persist through the next 24
hours, so little if any strengthening is expected during that time.
In fact, convection is likely to erode a little during the day
today, and then redevelop closer to the center tonight when the
shear begins to abate somewhat. In the 36-60 hour period, the shear
is forecast to weaken considerably from the northeast, allowing for
some slight strengthening to occur. However, the intensity is not
expected to increase to more than 35-40 kt, with the strongest
winds and heaviest rains remaining offshore the southwestern coast
of Mexico. For those reason, a tropical warning has not been issued
for southwestern Mexico at this time. The official intensity
forecast follows a blend of the HCCA, HWRF, and ECMWF models
intensity forecasts.
FORECAST POSITIONS AND MAX WINDS
INIT 26/0900Z 17.5N 106.7W 30 KT 35 MPH
12H 26/1800Z 18.1N 106.3W 30 KT 35 MPH
24H 27/0600Z 19.0N 106.3W 35 KT 40 MPH
36H 27/1800Z 20.1N 107.0W 35 KT 40 MPH
48H 28/0600Z 21.3N 108.1W 35 KT 40 MPH
60H 28/1800Z 22.3N 109.4W 35 KT 40 MPH
72H 29/0600Z 23.3N 111.3W 30 KT 35 MPH
96H 30/0600Z 23.3N 114.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 31/0600Z 22.7N 115.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Stewart
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