000
WTNT44 KNHC 012043
TCDAT4
 
TROPICAL STORM NADINE DISCUSSION NUMBER  77
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
500 PM AST MON OCT 01 2012
 
THE CONVECTIVE ORGANIZATION OF THE NEARLY THREE-WEEK-OLD NADINE HAS
NOT CHANGED MUCH THIS AFTERNOON...AND DEEP CONVECTION REMAINS
CONFINED TO A SINGLE BAND WHICH IS SLOWLY ROTATING AROUND THE
CENTER. DVORAK CI NUMBERS FROM TAFB AND SAB HAVE FALLEN TO 3.5 AND
3.0...RESPECTIVELY. THE INITIAL INTENSITY HAS BEEN LOWERED TO 55 KT
BASED ON THESE...AND A RECENT ASCAT PASS WHICH SHOWED WINDS OF
45-50 KT IN A CONVECTIVE-FREE LOCATION OF THE CIRCULATION.
 
NADINE HAS DRIFTED TO THE SOUTH THIS AFTERNOON...AND THE LONG-TERM
MOTION ESTIMATE IS NOW 180/4. WHILE THE TROPICAL STORM IS CURRENTLY
CAUGHT IN WEAK STEERING FLOW ON THE EASTERN SIDE OF A RIDGE OVER
THE CENTRAL ATLANTIC...IT IS EXPECTED TO PICK UP SPEED AND TURN TO
THE EAST AHEAD OF AN APPROACHING DEEP-LAYER TROUGH. BY DAY 3...MOST
OF THE MODELS SHOW NADINE BEING ADVECTED QUICKLY TO THE NORTH AS A
POST-TROPICAL LOW...BEFORE BECOMING COMPLETELY ABSORBED BY THE
TROUGH. THE GFS CONTINUES TO BE AN OUTLIER FROM THIS SOLUTION...AND
SHOWS THE RESILIENT CIRCULATION OF NADINE PUSHING EASTWARD ALL THE
WAY TO GREAT BRITAIN. OUT OF RESPECT FOR THE GFS...THE OFFICIAL
FORECAST SPLITS THE DIFFERENCE BETWEEN THESE TWO
POSSIBILITIES...HOWEVER...IT NOW SHOWS NADINE BEING ABSORBED BY DAY
5. THE DYNAMICAL GUIDANCE HAS SHIFTED A LITTLE TO THE SOUTH THIS
CYCLE...SO THE FORECAST HAS BEEN NUDGED IN THAT DIRECTION.
 
ADDITIONAL WEAKENING IS EXPECTED AS NADINE EXPERIENCES AN
INCREASINGLY HOSTILE ENVIRONMENT AHEAD OF THE TROUGH. THE MODEL
GUIDANCE IS IN GOOD AGREEMENT SHOWING STEADY WEAKENING FOR THE NEXT
FEW DAYS. MOST OF THE DYNAMICAL GUIDANCE INDICATES THAT ENOUGH OF A
PRESSURE GRADIENT WILL BE PRESENT TO MAINTAIN GALE-FORCE WINDS...
EVEN AS THE CYCLONE BECOMES POST-TROPICAL. THE NEW FORECAST IS A
LITTLE LOWER THAN THE PREVIOUS...AND REMAINS NEAR THE MODEL
CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/2100Z 35.4N  39.4W   55 KT  65 MPH
 12H  02/0600Z 35.0N  38.7W   50 KT  60 MPH
 24H  02/1800Z 34.7N  37.4W   45 KT  50 MPH
 36H  03/0600Z 34.7N  35.6W   45 KT  50 MPH
 48H  03/1800Z 35.8N  33.2W   40 KT  45 MPH
 72H  04/1800Z 42.4N  27.7W   40 KT  45 MPH...POST-TROPICAL
 96H  05/1800Z 47.5N  27.0W   40 KT  45 MPH...POST-TROPICAL
120H  06/1800Z...ABSORBED
 
$$
FORECASTER ZELINSKY/BROWN