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Hurricane Dora Discussion Number   7
NWS National Hurricane Center Miami FL       EP042017
900 AM MDT Mon Jun 26 2017

Dora has continued to rapidly intensify with a 20-nmi-diameter,
cloud-filled eye now evident in visible satellite imagery.  The
upper-level outflow pattern remains quite impressive and continues
to expand in all quadrants.  Satellite intensity estimates are a
consensus T4.5/77 kt from TAFB and SAB, and T4.7/82 kt from CIMSS
ADT, which supports an initial intensity of 75 kt. Dora could be a
little stronger, but recent infrared imagery indicates that the
inner-core convection has eroded significantly since the 1200 UTC
fixes, so the initial intensity will remain on the low end of
estimates for this advisory.

Dora has been holding on a steady west-northwestward course or
295/11 kt for the past 12 hours. A strong deep-layer subtropical
ridge entrenched to the north of the hurricane is expected to keep
Dora moving in a general west-northwestward motion for the next 3
days or so.  By 72 hours, the cyclone is expected to weaken
significantly and become a more vertically shallow system, steered
westward by the low-level trade wind flow until Dora dissipates by
day 5.  The new NHC track forecast is essentially just an update of
the previous advisory track, and lies a little south of the
consensus track model TVCE out of respect for the more southerly
ECMWF solution.

Dora has about another 12 hours or so to strengthen.  However, the
rapid intensification event that the hurricane has undergone for the
past 30 hours has likely ended.  The aforementioned erosion of the
inner-core convection is possibly due to the entrainment of cooler
and more stable air into the western semicircle now that Dora is
beginning to encroach upon 26-deg C SSTs.  The vertical wind
shear is expected to remain low at less than 5 kt and the favorable
upper-level outflow pattern is forecast to persist for the next few
days as well.  The only hindering factor will be the decreasing
thermodynamics due to the hurricane moving over sub-26C SSTs within
12-18 hours. Steady weakening should begin by 24 h, but the rate of
the weakening trend should be lessened due to proximity to warmer
water just south of the path of Dora and the aforementioned
favorable dynamic conditions. The NHC official intensity forecast is
similar to the previous advisory, and closely follows the consensus
model IVCN.

Although the center of Dora is forecast to remain well offshore, the
outer bands of the cyclone could bring brief locally heavy rainfall
to portions of coastal southwestern Mexico into this evening.

FORECAST POSITIONS AND MAX WINDS

INIT  26/1500Z 17.3N 106.3W   75 KT  85 MPH
 12H  27/0000Z 17.9N 107.7W   80 KT  90 MPH
 24H  27/1200Z 18.6N 109.5W   70 KT  80 MPH
 36H  28/0000Z 19.1N 111.1W   60 KT  70 MPH...NEAR SOCORRO ISLAND
 48H  28/1200Z 19.5N 112.7W   50 KT  60 MPH
 72H  29/1200Z 20.2N 115.7W   35 KT  40 MPH...POST-TROPICAL
 96H  30/1200Z 20.4N 118.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  01/1200Z...DISSIPATED

$$
Forecaster Stewart

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