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Tropical Storm Cosme Discussion Number 6
NWS National Hurricane Center Miami FL EP032019
200 PM PDT Sun Jul 07 2019
Deep convection has been pulsing since the previous advisory, with a
small burst of thunderstorms having recently developed in the
northwestern quadrant. Satellite data indicate that the low-level
center is less than 45 nmi from the -30 deg C cloud tops and cirrus
has been blowing off toward the southeast across the center,
indications that convective feedback is still maintaining Cosme as a
tropical cyclone. The initial intensity remains 35 kt for this
advisory based on a few 30-33 kt vectors that were present in an
1813Z ASCAT-B partial scatterometer pass over the northwestern
quadrant of Cosme's surface wind field.
The initial motion estimate is 315/09 kt. Cosme is expected to move
northwestward tonight and then turn toward the west-northwest by
Monday afternoon, maintaining that motion throughout the remainder
of the forecast period as the shallow circulation comes under the
influence of the low-level easterly trade wind flow. The new NHC
track forecast is a little north of the previous advisory track and
is similar to a blend of the HCCA, TVCE, and TVDG consensus models.
Cosme has just passed over the 26-deg-C SST isotherm and water
temperatures ahead of the cyclone are forecast to cool to near 24C
in about 24 hours. The combination of cooler waters, entrainment of
dry stable air, and increasing northwesterly wind shear is expected
to bring about the demise of Cosme in 12-24 hours. The cyclone is
expected to weaken to a tropical depression later tonight,
becoming a post-tropical system on Monday, and dissipating by 96
hours, if not sooner. The new official intensity forecast is similar
to the previous advisory, and closely follows the HCCA, FSSE, and
IVCN intensity consensus models.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 18.6N 119.0W 35 KT 40 MPH
12H 08/0600Z 19.2N 119.9W 30 KT 35 MPH
24H 08/1800Z 19.9N 120.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 09/0600Z 20.4N 121.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 09/1800Z 20.9N 122.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 10/1800Z 21.7N 124.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 11/1800Z...DISSIPATED
$$
Forecaster Stewart
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