ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM HURRICANE IVAN DISCUSSION NUMBER 25 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT WED SEP 08 2004 LAST FIX FROM A RECONNAISSANCE PLANE EARLIER THIS MORNING INDICATED THAT THE PRESSURE INCREASED TO 955 MB BUT FLIGHT-LEVEL WINDS WERE STILL 133 KNOTS IN THE NORTHERN EYEWALL. SINCE THEN...HIGH RESOLUTION VISIBLE SATELLITE IMAGES REVEAL THAT THE EYE IS NOT AS DISTINCT AS EARLIER BUT STILL VISIBLE. INITIAL INTENSITY REMAINS AT 120 KNOTS. BECAUSE THE HURRICANE WILL HAVE TO FIGHT SOME SHEAR AND WILL BE MOVING JUST NORTH OF THE SOUTH AMERICAN COAST...THERE MAY BE SOME WEAKENING DURING THE NEXT 12 TO 24 HOURS. THEREAFTER...THE HURRICANE WILL BE OVER THE NORTHWESTERN CARIBBEAN SEA WHERE THERE IS HIGH OCEANIC HEAT CONTENT AND LOWER SHEAR. SO...IVAN IS EXPECTED TO INTENSIFY BEFORE REACHING CUBA. NEVERTHERELESS...THESE ARE BASICALLY FLUCTUATIONS IN INTENSITY AND THE BOTTOM LINE IS THAT IVAN IS EXPECTED TO REMAIN A VERY DANGEROUS HURRICANE. SATELLITE AND EARLIER RECONNAISSANCE FIXES INDICATE THAT IVAN IS MOVING TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 14 KNOTS. DURING THE NEXT 24 TO 48 HOURS...THE SUBTROPICAL RIDGE TO THE NORTH OF IVAN IS EXPECTED TO CHANGE LITTLE...FORCING IVAN TO MOVE TOWARD THE WEST-NORTHWEST. THEREAFTER...THE RIDGE IS FORECAST TO WEAKEN AND A BROAD MID-LEVEL TROUGH WILL LIKELY BECOME ESTABLISHED OVER THE GULF OF MEXICO. THIS PATTERN SHOULD MOVE THE HURRICANE ON A NORTHWEST AND NORTH-NORTHWEST TRACK WITH A DECREASE IN FORWARD SPEED. IT MUST BE EMPHASIZED THAT THE FORECAST TRACK BEYOND 72 HOURS IS HIGHLY UNCERTAIN SINCE STEERING CURRENTS WILL BE WEAK AND ARE CURRENTLY NOT WELL-DEFINED IN THE FORECAST MODELS. IN FACT...SOME RELIABLE MODELS BRING IVAN OVER FLORIDA AND ANOTHER RELIABLE GROUP MOVE THE HURRICANE TOWARD THE GULF OF MEXICO. THERE IS NO APPARENT REASON TO FAVOR ONE SCENARIO OVER THE OTHER AT THIS TIME. THEREFORE...THE OFFICIAL FORECAST REMAINS NEAR THE GLOBAL MODEL CONSENSUS AND PRESUMES THAT THERE WILL BE ENOUGH RIDGING TO KEEP THE HURRICANE ON A NORTHWEST TO NORTH-NORTHWEST TRACK... BRINGING DANGEROUS IVAN OVER WESTERN CUBA IN 4 DAYS AND INTO THE EASTERN GULF OF MEXICO BY DAY FIVE. FORECASTER AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 08/1500Z 12.7N 66.2W 120 KT 12HR VT 09/0000Z 13.3N 68.3W 115 KT 24HR VT 09/1200Z 14.5N 71.0W 120 KT 36HR VT 10/0000Z 16.0N 73.5W 125 KT 48HR VT 10/1200Z 17.5N 76.0W 125 KT NEAR JAMAICA 72HR VT 11/1200Z 19.5N 79.0W 125 KT 96HR VT 12/1200Z 22.5N 82.0W 125 KT OVER WESTERN CUBA 120HR VT 13/1200Z 26.0N 84.0W 115 KT $$ NNNN
Alternate Formats
About Alternates -
E-Mail Advisories -
RSS Feeds
Cyclone Forecasts
Latest Advisory -
Past Advisories -
About Advisories
Marine Forecasts
Latest Products -
About Marine Products
Tools & Data
Satellite Imagery -
US Weather Radar -
Aircraft Recon -
Local Data Archive -
Forecast Verification -
Deadliest/Costliest/Most Intense
Learn About Hurricanes
Storm Names
Wind Scale -
Prepare -
Climatology -
NHC Glossary -
NHC Acronyms -
Frequently Asked Questions -
AOML Hurricane-Research Division
About Us
About NHC -
Mission/Vision -
Other NCEP Centers -
NHC Staff -
Visitor Information -
NHC Library
NOAA/
National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Wednesday, 08-Sep-2004 14:52:55 UTC