000
WTNT43 KNHC 100259
TCDAT3
 
HURRICANE MICHAEL DISCUSSION NUMBER  28
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL132012
1100 PM AST SUN SEP 09 2012
 
THE ENHANCED INFRARED SATELLITE PRESENTATION THIS EVENING INDICATES
SIGNIFICANT WEAKENING OF THE INNER CORE OF MICHAEL...WITH AN
OPENING OF THE EYE WALL IN THE NORTHWEST QUADRANT. IT APPEARS THAT
THE MUCH ANTICIPATED INCREASING NORTHERLY SHEAR IS FINALLY
BEGINNING TO AFFECT THE CYCLONE. A BLEND OF THE SUBJECTIVE AND
OBJECTIVE SATELLITE INTENSITY ESTIMATES SUPPORTS LOWERING THE
INITIAL INTENSITY TO 75 KT. THE NORTHERLY SHEAR...PRIMARILY
ASSOCIATED WITH THE OUTFLOW OF TROPICAL STORM LESLIE...SHOULD
CONTINUE TO IMPACT THE CLOUD PATTERN DURING THE NEXT 24-36 HOURS.
AFTER THAT TIME...INCREASING SOUTHWESTERLY SHEAR DOWNSTREAM FROM A
DEEP-LAYER BAROCLINIC SYSTEM AND COOLER SEAS SURFACE TEMPERATURES
SHOULD CAUSE THE CYCLONE TO WEAKEN SUBSTANTIALLY. SUBSEQUENTLY...
MICHAEL IS FORECAST TO LOSE SUFFICIENT TROPICAL CHARACTERISTICS AND
BECOME A POST-TROPICAL CYCLONE IN 48 HOURS...THEN TRANSITION TO AN
EXTRA-TROPICAL CYCLONE IN 72 HOURS. MICHAEL SHOULD ULTIMATELY
BECOME ABSORBED BY A FRONTAL SYSTEM AROUND DAY 4...OR EARLIER. THE
NHC INTENSITY FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS
ADVISORY AND IS BASED ON THE IVCN MODEL CONSENSUS.
 
THE INITIAL MOTION IS 265/5.  A MID-LEVEL RIDGE LOCATED NORTH OF
THE CYCLONE SHOULD KEEP IT ON A GENERAL WESTWARD MOTION DURING THE
NEXT 12 HOURS OR SO.  AFTERWARD...THE LARGE-SCALE MODELS SHOW
MICHAEL TURNING NORTHWESTWARD THEN NORTH-NORTHWESTWARD IN THE
WESTERN PERIPHERY OF THE AFOREMENTIONED EASTWARD-MOVING SHORTWAVE
RIDGE.  BEYOND 36 HOURS...A TURN TOWARD THE NORTH-NORTHEAST AND A
SIGNIFICANT INCREASE IN FORWARD SPEED IS FORECAST IN RESPONSE TO A
MID- TO UPPER-LEVEL TROUGH APPROACHING FROM THE ATLANTIC CANADIAN
MARITIMES.  THE OFFICIAL TRACK FORECAST IS A LITTLE TO THE LEFT OF
THE PREVIOUS ONE AND IS HEDGED TOWARD THE TVCA CONSENSUS AND THE
FLORIDA STATE SUPER ENSEMBLE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0300Z 33.6N  44.4W   75 KT  85 MPH
 12H  10/1200Z 33.8N  45.6W   70 KT  80 MPH
 24H  11/0000Z 34.8N  47.2W   60 KT  70 MPH
 36H  11/1200Z 37.3N  48.1W   50 KT  60 MPH
 48H  12/0000Z 40.9N  46.9W   45 KT  50 MPH...POST-TROPICAL
 72H  13/0000Z 48.0N  40.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  14/0000Z...ABSORBED BY A FRONT
 
$$
FORECASTER ROBERTS