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TROPICAL STORM BLANCA DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
400 PM CDT MON JUN 01 2015
Blanca continues to gradually organize, and satellite imagery shows
a developing CDO and numerous banding features. The initial
intensity has been raised to 40 kt based on a recent ASCAT-B
pass and a blend of the latest Dvorak estimates from TAFB and SAB.
Steady if not rapid intensification is expected during the next
couple of days while the shear is forecast to decrease over the
cyclone. In fact the SHIPS RI index has the highest probabilities
that I've seen, including an almost 90 percent chance of a 40-kt
increase in 24 hours. However, the regional hurricane models
continue to be much less bullish. The NHC official forecast
continues to be closest to the SHIPS model and shows Blanca becoming
a hurricane on Tuesday and nearing major hurricane intensity in 48
hours. It is possible that the rate of intensification could be even
faster than indicated here. Some weakening is expected by day 5 as
the cyclone begins to encounter cooler waters accompanied by an
increase in shear.
Blanca may have drifted a bit eastward over the past few hours, but
the initial motion estimate is stationary. Little net motion is
forecast during the next 72 hours while the steering currents remain
weak. At days 4 and 5 a northwestward track is expected to begin as
a ridge builds to the northeast of Blanca over northern Mexico. The
latest NHC track forecast is similar to the previous one during the
first 72 hours and has been adjusted eastward at days 4-5 following
the trend of the latest multi-model consensus.
Blanca is expected to remain well offshore of the southwestern coast
of Mexico through the forecast period. However, some rainbands on
the outer periphery of the circulation could affect portions of the
coast during the next couple of days.
FORECAST POSITIONS AND MAX WINDS
INIT 01/2100Z 13.3N 103.9W 40 KT 45 MPH
12H 02/0600Z 13.4N 104.3W 55 KT 65 MPH
24H 02/1800Z 13.3N 104.5W 70 KT 80 MPH
36H 03/0600Z 13.1N 104.7W 85 KT 100 MPH
48H 03/1800Z 12.8N 104.8W 95 KT 110 MPH
72H 04/1800Z 13.2N 105.1W 110 KT 125 MPH
96H 05/1800Z 16.0N 107.5W 110 KT 125 MPH
120H 06/1800Z 19.0N 109.5W 90 KT 105 MPH
$$
Forecaster Brennan
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