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Tropical Storm Boris Discussion Number 7
NWS National Hurricane Center Miami FL EP032020
500 PM HST Thu Jun 25 2020
Deep convection associated with Boris has decreased in coverage
since the previous advisory, however a new band of convection has
recently developed over the eastern semicircle of the cyclone. The
initial wind speed remains 35 kt and is based on the earlier ASCAT
data and a Dvorak current intensity (CI) number of T2.5 or 35 kt
from SAB. Boris remains within an area of low vertical wind shear
and over warm sea surface temperatures, however dry mid-level air
just to the north and northwest of the storm continues to be
entrained into the circulation. As a result, little change in
strength is anticipated over the next 12 h or so, and after that
time, Boris will be moving into the drier and more stable air
mass which should cause gradual weakening. The new NHC intensity
forecast is unchanged from the previous advisory, and calls for
Boris to degenerate into a remnant low by 60 h, and dissipate
between 72 and 96 h.
The initial motion estimate is west-northwestward or 290 at 8 kt.
The track forecast reasoning remains unchanged from the previous
advisory. Boris should move west-northwestward during the next 24
hours while it remains to the south of a low- to mid-level ridge.
After that time, the cyclone should turn westward, then west-
southwestward later in the forecast period as the cyclone weakens
and is steered by the low-level trade wind flow. The updated NHC
forecast track is very close to the previous official forecast, and
along the southern side of the guidance envelope.
FORECAST POSITIONS AND MAX WINDS
INIT 26/0300Z 11.4N 137.9W 35 KT 40 MPH
12H 26/1200Z 11.8N 138.9W 35 KT 40 MPH
24H 27/0000Z 12.1N 140.0W 30 KT 35 MPH
36H 27/1200Z 12.3N 141.2W 30 KT 35 MPH
48H 28/0000Z 12.3N 142.8W 25 KT 30 MPH
60H 28/1200Z 12.1N 144.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/0000Z 11.8N 146.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 30/0000Z...DISSIPATED
$$
Forecaster Brown
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