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Tropical Depression ONE-E


Tropical Depression One-E Discussion Number   3
NWS National Hurricane Center Miami FL       EP012019
300 AM MDT Wed Jun 26 2019

The overall convective pattern of the cyclone has changed little
since the previous advisory. However, passive microwave images
indicate that the low-level center has become less distinct and that
the inner-core convection has become ragged. In addition, the
coldest cloud tops have migrated from north through east to now
south of the center during the past 12 hours, another indication
that the inner-core of the depression is undergoing some structural
changes. Although no ASCAT wind data are available over the
cyclone's core, a 0417Z ASCAT-C pass did catch the western portion
of the circulation and only showed northerly winds of 5-10 kt within
30 nmi of the center, which suggests that the surface wind field
might not be as well developed as the circulation aloft is.

The initial position and the 275/13-kt motion are based on a blend
of microwave and conventional fixes, and also continuity with the
previous motion vector. The latest track model guidance is in decent
agreement on a westward to west-northwestward motion accompanied by
a gradual decrease in forward speed over the next few days as a
strong deep-layer subtropical ridge holds steady to the north of the
cyclone. The new NHC track forecast is similar to but south of the
previous advisory track, mainly due to the more southerly initial
position. As mentioned in the previous forecast package, the 00Z
ECMWF model continues to show a more southward dip in the track
during the next 24 h. That is a viable alternate track scenario if
the center redevelops farther south closer to the coldest
overshooting cloud tops later this morning.

There is a narrow window of opportunity for the system to strengthen
into a tropical storm during the next 24 h or so while the cyclone
remains over warm water and in low vertical wind shear conditions.
By 36-48 hours, the cyclone is expected to move over sub-26C SSTs
and into a more stable environment that is not conducive for
generating vigorous convection despite the favorable low-shear
conditions forecast at that time. The combination of cooler waters,
drier mid-level air, and increasing southwesterly wind shear shear
are expected to induce steady weakening in 48-96 hours, with
dissipation forecast by 120 h. The official intensity forecast is
similar to the previous advisory, and follows the IVCN and ICON
intensity consensus models.


INIT  26/0900Z 15.5N 108.3W   30 KT  35 MPH
 12H  26/1800Z 15.6N 110.3W   35 KT  40 MPH
 24H  27/0600Z 15.8N 112.7W   35 KT  40 MPH
 36H  27/1800Z 16.4N 114.9W   35 KT  40 MPH
 48H  28/0600Z 17.0N 116.9W   30 KT  35 MPH
 72H  29/0600Z 18.1N 120.4W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  30/0600Z 18.8N 123.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  01/0600Z...DISSIPATED

Forecaster Stewart