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Hurricane Linda Discussion Number 27
NWS National Hurricane Center Miami FL EP122021
1100 AM HST Mon Aug 16 2021
Linda still has a very striking appearance on visible satellite
imagery, with a well-defined large eye, and multiple eyewall
mesovorticies rotating about the mean center. However, the ring of
cold cloud tops associated with the eyewall has become just a touch
more ragged over the last few hours, and an earlier SSMIS microwave
pass at 1518 UTC showed a break in the singular eyewall on the south
side. The 1800 UTC Dvorak CI numbers were steady from SAB and TAFB,
but the data-T numbers have decreased a bit from earlier today. In
addition, the latest UW-CIMSS ADT intensity estimate was down to
T4.8/85-kt. Therefore, Linda is estimated to be a bit weaker this
advisory, with maximum sustained winds near 85-kt.
The initial motion is beginning to turn a bit more westward, now at
260/8 kt. A well-established mid-level ridge north of Linda is
expected to build in gradually to the northeast, allowing the storm
to begin gaining latitude starting tomorrow. This west-northwest
track is then expected to continue through the forecast period. The
latest NHC track forecast is very close to the previous one, and is
closest to the GEFX consensus, which is a simple blend of the most
recent GFS and ECMWF forecasts.
As discussed in previous advisories, Linda is expected to remain in
a low deep-layer vertical-wind-shear environment (below 10 kt) for
the next 4-5 days. Thus, Linda's intensity forecast is expected to
be driven by a combination of thermodynamic factors and the
cyclone's stable annular inner-core structure. While sea-surface
temperatures (SSTs) are only between 25-26 C under the hurricane
right now, the forecast track takes Linda back over slightly warmer
SSTs in the 12-36 h period, and this could delay weakening in the
short-term. The NHC intensity forecast continues to be above much of
the intensity guidance, showing little change in intensity over the
next 24-36 hours. In fact, when Linda moves over slightly warmer
SSTs tomorrow, it would not be surprising to see a bit of
restrengthening, assuming nearby dry-air does not disrupt the stable
eyewall structure. However by 48 hours, SSTs decrease below 26 C in
earnest and Linda is expected to begin a pronounced weakening trend.
Towards the end of the forecast, Linda should become devoid of deep
convection as indicated by the latest GFS and ECMWF IR brightness
temperature forecast, and Linda is expected to become a
post-tropical gale by Friday.
FORECAST POSITIONS AND MAX WINDS
INIT 16/2100Z 17.7N 124.6W 85 KT 100 MPH
12H 17/0600Z 17.6N 125.9W 85 KT 100 MPH
24H 17/1800Z 17.7N 127.7W 85 KT 100 MPH
36H 18/0600Z 18.2N 129.8W 85 KT 100 MPH
48H 18/1800Z 19.0N 132.2W 75 KT 85 MPH
60H 19/0600Z 19.9N 134.8W 60 KT 70 MPH
72H 19/1800Z 20.7N 137.5W 50 KT 60 MPH
96H 20/1800Z 22.0N 142.6W 40 KT 45 MPH...POST-TROPICAL
120H 21/1800Z 23.0N 146.8W 35 KT 40 MPH...POST-TROPICAL
$$
Forecaster Papin/Brown
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