NHC亦升格為TD-07E

ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM

Tropical Depression Seven-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP072020
1100 PM HST Sun Jul 19 2020

The small low pressure are that the National Hurricane Center has
been tracking for the past couple of days has finally developed
enough persistent organized deep convection for the  system to
classified as Tropical Depression Seven-E. An earlier burst of
strong convection with cloud tops colder than -80C helped to spin up
the low-level wind field and cause the center to become better
defined based on a 0529 UTC ASCAT-A overpass. The aforementioned
scatterometer data showed surface winds of 29-30 kt in the western
semicircle, which is the basis for the 30-kt initial intensity. This
intensity is also supported by 06Z Dvorak satellite intensity
estimates of T2.0/30 kt from both TAFB and SAB.

The initial motion estimate is 310/10 kt based on conventional,
microwave, and scatterometer satellite fix data over the past 12
hours. The small cyclone is expected to be steered northwestward to
west-northwestward at about the same forward speed for the next day
or so due to a strong subtropical ridge situated to the north of the
depression. By 24-36 h, the system is forecast to degenerate into a
shallow remnant low and be steered westward through 48-60 h,
followed by a turn toward the southwest before dissipating by 96 h.
The NHC official forecast track lies close to the tightly packed
simple consensus models, which is consistent with the NOAA
corrected-consensus model, HCCA.

Although the vertical wind shear is expected to remain low at less
than 5 kt for the next 24 h or so, the small cyclone is already
moving over sub-26 deg C sea-surface temperatures (SST), with
slightly cooler water ahead of the system. The ingestion of cooler
and drier air, along with the cool SSTs, is expected to weaken the
system below depression status by 24 h. Although it is possible that
the system could hold on to tropical cyclone status a little longer
than currently indicated, especially when the system moves
southwestward toward warmer water, moderate to strong southwesterly
vertical wind shear should cause the small cyclone to dissipate by
96 h. The official intensity forecast closely follows the IVCN
intensity consensus model.

FORECAST POSITIONS AND MAX WINDS

INIT  20/0900Z 18.0N 129.3W   30 KT  35 MPH
12H  20/1800Z 18.7N 130.7W   30 KT  35 MPH
24H  21/0600Z 19.3N 132.6W   25 KT  30 MPH...POST-TROPICAL
36H  21/1800Z 18.9N 134.8W   25 KT  30 MPH...POST-TROPICAL
48H  22/0600Z 18.0N 137.2W   20 KT  25 MPH...POST-TROPICAL
60H  22/1800Z 16.0N 139.6W   20 KT  25 MPH...POST-TROPICAL
72H  23/0600Z 13.7N 141.9W   20 KT  25 MPH...POST-TROPICAL
96H  24/0600Z...DISSIPATED

$$
Forecaster Stewart

NNNN

JTWC 05Z 風速測得30kt以上，故於20/06Z升格為07E

EP, 07, 2020072006, , BEST, 0, 177N, 1289W, 30, 1007, TD, 34, NEQ, 0, 0, 0, 0, 1011, 120, 30, 0, 0, E, 0, , 0, 0, SEVEN, D, 0, , 0, 0, 0, 0, genesis-num, 013, TRANSITIONED, epA92020 to ep072020,