Tropical Cyclone Forecasts/Advisories

Tropical cyclone forecasts/advisories are intended mainly for ships at sea and other marine interests, but they are also very useful to emergency managers because they contain wind field information in the standard format of 12-, 24-, 36-, 48-, and 72-hour forecast positions (see the example below from Hurricane Georges, 1998). These products generally include the following information
  • Watches and warnings
  • Present conditions and accuracy
  • Eye diameter
  • 72-hour forecast maximum sustained wind speeds and gusts
  • 72-hour forecast wind radii for the 34 kt, 50 kt, 64 kt winds (shown in red below)
  • Tides
  • Request for ship reports
  • Time of next advisory
  • The forecaster's name

Tropical cyclone forecasts/advisories are issued at 6-hour intervals, but special forecasts/advisories may be issued to provide information about any abrupt or significant change that may have occurred since the time of the last regular forecast/advisory.

 
ZCZC MIATCMAT2 TTAA00 KNHC 240901
HURRICANE GEORGES FORECAST/ADVISORY NUMBER 36
NATIONAL WEATHER SERVICE MIAMI FL AL0798

0900Z THU SEP 24 1998             [Explanation of the "Z" time system]

AT 5 AM EDT...0900Z...A HURRICANE WARNING IS NOW IN EFFECT FOR SOUTH FLORIDA...FROM DEERFIELD BEACH SOUTHWARD ON THE EAST COAST AND FROM BONITA BEACH SOUTHWARD ON THE WEST COAST...INCLUDING THE FLORIDA KEYS. THIS INCLUDES MONROE...MIAMI DADE...BROWARD AND COLLIER COUNTIES.

A HURRICANE WATCH IS NOW IN EFFECT FROM STUART TO DEERFIELD BEACH ON THE FLORIDA EAST COAST AND FROM SOUTH OF LONGBOAT KEY SOUTHWARD TO BONITA BEACH ON THE FLORIDA WEST COAST. THIS INCLUDES PALM BEACH...MARTIN...SARASOTA...CHARLOTTE AND LEE COUNTIES...

HURRICANE WARNINGS ARE DISCONTINUED FOR HAITI. INTERESTS THERE SHOULD EXERCISE CAUTION UNTIL WINDS AND SEAS SUBSIDE.

A TROPICAL STORM WARNING REMAINS IN EFFECT FOR CAYMAN BRAC...AND LITTLE CAYMAN ISLAND. TROPICAL STORM WARNINGS ARE DISCONTINUED FOR JAMAICA.

HURRICANE CENTER LOCATED NEAR 21.1N 76.7W AT 24/0900Z
POSITION ACCURATE WITHIN 90 NM

PRESENT MOVEMENT TOWARD THE WEST NORTHWEST OR 300 DEGREES AT 10 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 992 MB
MAX SUSTAINED WINDS 65 KT WITH GUSTS TO 80 KT
64 KT....... 30NE 0SE 0SW 0NW
50 KT.......100NE 100SE 30SW 30NW
34 KT.......135NE 125SE 75SW 125NW
12 FT SEAS..300NE 150SE 150SW 300NW
ALL QUADRANT RADII IN NAUTICAL MILES

REPEAT...CENTER LOCATED NEAR 21.1N 76.7W AT 24/0900Z
AT 24/0600Z CENTER WAS LOCATED NEAR 20.7N 76.2W

FORECAST VALID 24/1800Z 21.9N 78.1W
MAX WIND 65 KT...GUSTS 80 KT
64 KT... 30NE 0SE 0SW 0NW
50 KT...100NE 100SE 30SW 30NW
34 KT...135NE 125SE 75SW 125NW

FORECAST VALID 25/0600Z 23.3N 79.9W
MAX WIND 70 KT...GUSTS 85 KT
64 KT... 30NE 0SE 0SW 0NW                                    [Explanation of this table]
50 KT...100NE 100SE 30SW 30NW
34 KT...135NE 125SE 75SW 125NW

FORECAST VALID 25/1800Z 24.8N 81.8W
MAX WIND 80 KT...GUSTS 95 KT
64 KT... 30NE 30SE 30SW 30NW
50 KT...100NE 75SE 50SW 50NW
34 KT...150NE 125SE 75SW 125NW

STORM SURGE FLOODING OF 4 TO 7 FEET ABOVE NORMAL TIDE LEVELS... ACCOMPANIED BY LARGE AND DANGEROUS BATTERING WAVES ARE EXPECTED ALONG THE COAST IN THE WARNING AREA.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.1N 76.7W

EXTENDED OUTLOOK...USE FOR GUIDANCE ONLY...ERRORS MAY BE LARGE

OUTLOOK VALID 26/0600Z 26.2N 83.3W
MAX WIND 85 KT...GUSTS 105 KT
50 KT...100NE 75SE 50SW 50NW

OUTLOOK VALID 27/0600Z 29.0N 86.0W
MAX WIND 85 KT...GUSTS 105 KT
50 KT...100NE 75SE 50SW 50NW

NEXT ADVISORY AT 24/1500Z

LAWRENCE

STRIKE PROBABILITIES ASSOCIATED WITH THIS ADVISORY NUMBER CAN BE FOUND UNDER AFOS HEADER MIASPFAT2 AND WMO HEADER WTNT72 KNHC.