815
WTNT43 KNHC 291449
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082026
1100 AM AST TUE SEP 29 2026
SATELLITE IMAGERY THIS MORNING SHOWS THAT HANNA CONTINUES AS A
SHEARED TROPICAL CYCLONE WITH THE LOW-LEVEL CENTER MOSTLY EXPOSED TO
THE WEST OF THE MAIN CONVECTIVE AREA. THE CYCLONE ALSO REMAINS JUST
SOUTH OF A WEAK FRONTAL BOUNDARY. BASED ON A JUST RECEIVED ASCAT
OVERPASS, THE INITIAL INTENSITY IS REDUCED TO 35 KT. THE
SCATTEROMETER DATA ALSO SUGGESTS THAT THE CIRCULATION IS BECOMING
LESS WELL DEFINED AS IT INTERACTS WITH THE FRONTAL BOUNDARY.
THE INITIAL MOTION IS NOW 125/10 KT. THERE IS LITTLE CHANGE TO THE
TRACK FORECAST REASONING FROM THE PREVIOUS ADVISORY. HANNA IS
EMBEDDED IN THE FLOW BETWEEN A BROAD MID-LATITUDE TROUGH TO ITS
NORTHEAST AND A LARGER SUBTROPICAL RIDGE TO ITS SOUTH. THIS SYNOPTIC
PATTERN SHOULD RESULT IN A SOUTHEASTWARD OR EAST-SOUTHWARD MOTION
OVER THE NEXT 12-24 H WITH A GRADUAL DECREASE IN FORWARD SPEED. AN
EAST-NORTHEASTWARD MOTION IS THEN EXPECTED AS THE CYCLONE BECOMES
VERTICALLY SHALLOW AND INFLUENCED BY A LOW-LEVEL RIDGE CENTERED
SOUTH OF THE AZORES. THE NEW FORECAST TRACK IS SIMILAR TO THE
PREVIOUS TRACK AND IS IN BEST AGREEMENT WITH THE HFIP CORRECTED
CONSENSUS MODEL.
HANNA SHOULD GRADUALLY WEAKEN DUE TO SHEAR AND DRY AIR ENTRAINMENT,
AND THE SYSTEM IS LIKELY TO STOP PRODUCING CONVECTION AND
DEGENERATE TO A REMNANT LOW BETWEEN 36-48 H BASED ON GLOBAL MODEL
SIMULATED SATELLITE IMAGERY. THE SYSTEM IS EXPECTED TO WEAKEN TO A
TROUGH BY 96 H.
FORECAST POSITIONS AND MAX WINDS
INIT 29/1500Z 34.6N 45.5W 35 KT 40 MPH
12H 30/0000Z 34.0N 44.2W 35 KT 40 MPH
24H 30/1200Z 33.9N 43.0W 35 KT 40 MPH
36H 01/0000Z 34.5N 41.6W 35 KT 40 MPH
48H 01/1200Z 35.3N 39.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 02/0000Z 36.4N 37.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 02/1200Z 37.4N 34.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 03/1200Z...DISSIPATED
FORECASTER BEVEN
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