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Tropical Storm HENRIETTE


Tropical Storm Henriette Discussion Number   5
NWS National Hurricane Center Miami FL       EP092019
900 PM MDT Mon Aug 12 2019

Scatterometer data and visible satellite imagery indicate that
Henriette has maintained a robust, compact low-level circulation
despite the pulsing convection. In fact, three earlier ASCAT passes
between 1613Z and 1728Z indicated reliable wind speeds of 37-38 kt,
suggesting that Henriette could have been near 40 kt prior to those
times. However, since 1800Z, northeasterly vertical wind shear
and dry air intrusions have reduced and confined the overall
convective pattern to just intermittent bursts in the southwestern
quadrant. The initial intensity is being maintained at 35 kt based
on the shear pattern, a UW-CIMSS ADT intensity estimate of T2.4/34
kt, and allowing for some slight spin down of the low-level vortex.

The initial motion remains 290/11 kt. A west-northwestward motion
is forecast to continue for the next 24 hours so, followed by a
turn toward the west by early Wednesday as the weakening cyclone
becomes vertically shallow and gets steered by the low-level
easterly tradewind flow. The new NHC forecast track remains
essentially unchanged and is just an extension of the previous
advisory, and lies about midway between the consensus models HCCA
and TVCE.

Although the official intensity forecast calls for steady weakening,
it is possible that Henriette could remain a tropical storm in 12 h
due to the cyclone coming out of the convective maximum period and
still located over SSTs between 26C and 26.5 deg C. However, by 18 h
and beyond, the cyclone will be moving over sub-26C SSTs and into a
drier environment, which is expected to result in significant
weakening, with Henriette degenerating into a remnant low by late
Tuesday and dissipating by late Wednesday. The official intensity
forecast is identical to previous advisory and closely follows the
IVCN and HCCA consensus intensity forecast models.


INIT  13/0300Z 20.7N 114.3W   35 KT  40 MPH
 12H  13/1200Z 21.2N 116.0W   30 KT  35 MPH
 24H  14/0000Z 21.8N 118.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  14/1200Z 22.3N 121.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  15/0000Z...DISSIPATED

Forecaster Stewart