Tropical Storm GILMA
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TROPICAL STORM GILMA DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072012
800 AM PDT WED AUG 08 2012
FIRST-LIGHT VISIBLE IMAGERY SHOWS THAT GILMA HAS A WELL-DEVELOPED
CENTRAL DENSE OVERCAST...WITH OUTER CONVECTIVE BANDS PRESENT IN ALL
QUADRANTS EXCEPT THE NORTHEAST. SATELLITE INTENSITY ESTIMATES ARE
65 KT FROM TAFB AND 55 KT FROM SAB...SO THE INITIAL INTENSITY
REMAINS JUST BELOW HURRICANE STRENGTH AT 60 KT. THE CIRRUS OUTFLOW
IS GOOD TO EXCELLENT IN ALL DIRECTIONS EXCEPT TO THE NORTHEAST.
THE INITIAL MOTION REMAINS 285/11 KT. THE CYCLONE IS BEING STEERED
BY A MID- TO UPPER-LEVEL RIDGE EXTENDING WESTWARD OVER THE
NORTHEASTERN PACIFIC FROM THE SOUTHWESTERN UNITED STATES. THIS
SHOULD KEEP GILMA ON A WEST-NORTHWESTWARD TRACK AT A DECREASING
FORWARD SPEED DURING THE NEXT 24 HR OR SO. AFTER THAT...THE GLOBAL
MODELS CONTINUE TO SHOW INTERACTION WITH A LARGE AREA OF BROAD LOW-
TO MID-LEVEL CYCLONIC FLOW...POSSIBLY INCLUDING THE REMNANTS OF
ATLANTIC HURRICANE ERNESTO...WHICH ARE EXPECTED TO MOVE INTO THE
PACIFIC IN 60-72 HR. THE GUIDANCE BECOMES VERY DIVERGENT BY 120
HR...WITH THE ECMWF AS FAR WEST AS 126W...THE UKMET AS FAR EAST AS
116W...AND THE OTHER DYNAMICAL GUIDANCE SCATTERED BETWEEN THESE
EXTREMES. THE OFFICIAL FORECAST DURING THIS TIME CALLS FOR A SLOW
NORTHWESTWARD MOTION SIMILAR TO THE PREVIOUS FORECAST...WITH THE
NEW TRACK LYING NEAR THE CENTER OF THE TRACK GUIDANCE ENVELOPE.
GILMA IS CURRENTLY NEAR SEA SURFACE TEMPERATURES OF NEAR 28C...AND
THE FORECAST TRACK TAKES THE CYCLONE OVER COOLER WATERS. FAVORABLE
UPPER-LEVEL WINDS SHOULD ALLOW THE CYCLONE TO STRENGTHEN FOR
ANOTHER 12-24 HR. AFTER THAT...THE LOWER SSTS SHOULD CAUSE A
STEADY WEAKENING. THE NEW INTENSITY FORECAST CALLS FOR GILMA TO BE
A HURRICANE FROM 12-36 HR...FOLLOWED BY WEAKENING TO A TROPICAL
DEPRESSION BY 96 HR. THE CYCLONE IS FORECAST TO DEGENERATE TO A
REMNANT LOW BY 120 HR.
FORECAST POSITIONS AND MAX WINDS
INIT 08/1500Z 16.0N 117.1W 60 KT 70 MPH
12H 09/0000Z 16.5N 118.2W 65 KT 75 MPH
24H 09/1200Z 17.1N 119.3W 70 KT 80 MPH
36H 10/0000Z 17.6N 120.1W 65 KT 75 MPH
48H 10/1200Z 18.2N 120.8W 60 KT 70 MPH
72H 11/1200Z 19.5N 121.5W 45 KT 50 MPH
96H 12/1200Z 20.0N 122.0W 30 KT 35 MPH
120H 13/1200Z 20.5N 122.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
FORECASTER BEVEN
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