Replies

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WTNT43 KNHC 292025
TCDAT3
Tropical Storm Bill discussion number 2
National Weather Service Tropical Prediction Hurricane Center Miami, Florida
5 PM EDT Sunday, June 29, 2003

Reports from an air force reserve reconnaissance aircraft this afternoon indicate that low level circulation center is not very well defined. This makes the initial motion rather uncertain. The initial motion estimate is 335/11. The track guidance is in good agreement about turning the storm north and then eastward around the western periphery of a mid level high pressure ridge extending eastward from the eastern Gulf of Mexico. However the guidance also shifts the tracks eastward about 100 n mi from the previous advisory and so does the official forecast. This is partially due to shifting the initial position eastward. This also requires an eastward shift to the watch area which will also be changed to a warning.

The aircraft measured a central pressure of 1010 millibars, not very low, but the pressure gradient to the east of the storm is large. A 15Z ship report of 40 knots about 80 nautical miles northeast of the center, along with aircraft observations, is the basis for increasing the wind speed to 40 knots. The ships model brings the wind to 62 knots in 24 hours under light shear and warm sea-surface temperatures. In contrast none of the global models show strengthening. Also the present deep convection pattern is not very impressive. The official forecast is a compromise 55 knots at 24 hours.

Forecaster Lawrence

Forecast positions and max winds

Initial 29/2100Z 24.8°N, 91.1°W 40 knots
12 hour 30/0600Z 26.4°N, 91.9°W 45 knots
24 hour 30/1800Z 28.5°N, 92.5°W 55 knots
36 hour 01/0600Z 30.5°N, 92.0°W 30 knots, inland
48 hour 01/1800Z 31.5°N, 90.5°W 20 knots, inland
72 hour 02/1800Z 33.0°N, 86.0°W 20 knots, inland
96 hour 03/1800Z, inland

WTNT33 KNHC 292023
TCPAT3
Bulletin
Tropical Storm Bill advisory number 2
National Weather Service Tropical Prediction Hurricane Center Miami, Florida
5 PM EDT Sunday, June 29, 2003

At 4 PM CDT, 2100Z, a tropical storm warning is in effect from east of High Island, Texas to Pascagoula, Mississippi. The tropical storm watch from San Luis Pass to High Island is discontinued. A tropical storm warning means that tropical storm conditions are expected within the warning area within the next 24 hours.

At 4 PM CDT, 2100z, the center of tropical storm bill was located near latitude 24.8 north, longitude 91.1 west or about 325 miles south of Morgan City, Louisiana.

Bill is moving toward the north-northwest near 13 mph and a turn toward the north is expected during the next 24 hours.

Maximum sustained winds have increased to near 45 miles per hour with higher gusts. Some strengthening is forecast during the next 24 hours.

Tropical storm force winds extend outward up to 175 miles mainly to the east of the center.

The estimated minimum central pressure is 1010 millibars, 29.83 inches of mercury.

Storm surge coastal flooding is expected to be about 3 to 5 feet above normal tide levels near and to the east of where the center moves inland.

Heavy rain is expected to move inland late tonight and Monday with amounts in the 5 to 8 inch range.

Repeating, the 4 PM CDT position is 24.8°N, 91.1° W. Movement is toward north-northwest near 13 miles per hour. Maximum sustained winds are 45 miles per hour. Minimum central pressure is 1010 millibars.

For storm information specific to your area, please monitor products issued by your local weather office.

An intermediate advisory will be issued by the National Hurricane Center at 7 PM CDT followed by the next complete advisory at 10 PM CDT.

Forecaster Lawrence