Tropical Storm HERNAN
ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM HERNAN DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082014
800 AM PDT SUN JUL 27 2014
Enhanced BD-curve infrared imagery and an earlier GCOM-W1 (AMSR2)
microwave overpass indicate that Hernan has continued to strengthen
this morning. The imagery shows an impressive well-developed
banding feature over the northwest quadrant of the cyclone with -80
to -90 deg C cloud tops, while the microwave pass reveals a more
distinct inner core with a partial eyewall feature. Based on a
blend of the Dvorak classifications from TAFB and SAB, and the
latest UW-CIMSS SATCON estimate, the NHC initial intensity is raised
to 60 kt.
Current favorable environmental conditions should allow for further
intensification during the next 8-12 hours, and Hernan still has a
chance to become a hurricane today or tonight. Afterward,
increasing westerly shear and decreasing sea surface temperatures
are expected to weaken Hernan through the remainder of the forecast
period. The available statistical/dynamical guidance agree with
weakening Hernan into a remnant low in 96 hours.
The initial motion is estimated to be northwestward, or 305/13 kt.
Hernan continues to be steered by the mid-level southeasterly flow
produced by a ridge over the southwestern United States. The
cyclone should move in this general direction through the 36 hour
period, and then turn westward within the low-level trade wind flow
as a degenerated, vertically shallow system. The official NHC
forecast is based on the multi-model consensus and is slightly to
the right of the previous forecast beyond 48 hours.
FORECAST POSITIONS AND MAX WINDS
INIT 27/1500Z 17.8N 111.1W 60 KT 70 MPH
12H 28/0000Z 19.0N 112.8W 65 KT 75 MPH
24H 28/1200Z 20.5N 115.2W 60 KT 70 MPH
36H 29/0000Z 21.9N 117.6W 50 KT 60 MPH
48H 29/1200Z 22.9N 119.8W 45 KT 50 MPH
72H 30/1200Z 23.9N 123.0W 30 KT 35 MPH
96H 31/1200Z 24.0N 126.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 01/1200Z 24.0N 129.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Roberts
NNNN