Tropical Storm HILARY
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TROPICAL STORM HILARY DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092011
800 PM PDT WED SEP 21 2011
THE CLOUD PATTERN HAS CONTINUED TO CONSOLIDATE AND DEEP CONVECTION
HAS INCREASED NEAR THE CENTER. IN FACT...MICROWAVE DATA DURING THE
AFTERNOON AND EARLY EVENING REVEAL A DISTINCT RING OF DEEP
CONVECTION INDICATING THAT THE INNER CORE IS BECOMING BETTER
ORGANIZED. T-NUMBERS FROM BOTH TAFB AND SAB HAVE INCREASED TO 3.0
YIELDING AN INITIAL INTENSITY OF 45 KNOTS. GIVEN THE LOW SHEAR AND
THE WARM OCEAN...STRENGTHENING IS INDICATED AND HILARY IS EXPECTED
TO BECOME A HURRICANE BY THURSDAY WITH THE GOOD POSSIBILITY OF
RAPID INTENSIFICATION. THE OFFICIAL FORECAST FOLLOWS VERY CLOSE
THE STATISTICAL LGEM MODEL BUT IS NOT AS AGGRESSIVE AS THE HWRF.
HILARY IS MOVING TOWARD THE WEST-NORTHWEST AT ABOUT 6 KNOTS. THE
STEERING CURRENTS ARE WEAK BUT MOST OF THE GLOBAL MODELS GRADUALLY
BUILD THE SUBTROPICAL RIDGE TO THE NORTH OF THE CYCLONE. THIS
PATTERN SHOULD FAVOR A CONTINUATION OF THE WEST-NORTHWESTWARD MOTION
WITH A SLIGHT INCREASE IN FORWARD SPEED. WITH THE EXCEPTION OF THE
HWRF/GFDL PAIR WHICH TURNS HILARY NORTHWARD TOWARD BAJA CALIFORNIA
OR THE GULF OF CORTES BY THE END OF THE FORECAST PERIOD...THE REST
OF THE GUIDANCE KEEPS HILARY ON A GENERAL WEST-NORTHWEST TRACK
THROUGH FIVE DAYS AND SO DOES THE OFFICIAL FORECAST.
GIVEN THE GOOD PROSPECTS FOR INTENSIFICATION...A TRACK NOT TOO FAR
TO THE SOUTHWEST COAST OF MEXICO...AND THE WIND RADII...A TROPICAL
STORM WARNING HAS BEEN ISSUED FOR A PORTION OF THE COAST.
FORECAST POSITIONS AND MAX WINDS
INIT 22/0300Z 14.4N 97.2W 45 KT 50 MPH
12H 22/1200Z 14.7N 98.0W 55 KT 65 MPH
24H 23/0000Z 15.2N 99.5W 65 KT 75 MPH
36H 23/1200Z 15.8N 101.5W 75 KT 85 MPH
48H 24/0000Z 16.5N 103.5W 80 KT 90 MPH
72H 25/0000Z 18.0N 107.0W 90 KT 105 MPH
96H 26/0000Z 18.5N 110.5W 90 KT 105 MPH
120H 27/0000Z 19.0N 113.5W 80 KT 90 MPH
$$
FORECASTER AVILA
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