364  
WTNT42 KNHC 202033  
TCDAT2  
 
TROPICAL STORM ROSE DISCUSSION NUMBER 7  
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172021  
500 PM AST MON SEP 20 2021  
 
SATELLITE IMAGES SHOW THAT ROSE HASN'T CHANGED MUCH DURING THE PAST  
SEVERAL HOURS, WITH THE CENTER ON THE NORTHERN SIDE OF THE CLOUD  
SHIELD. THE LAST MICROWAVE PASS FROM A FEW HOURS AGO SHOWED THAT  
THE MID- AND LOW-LEVEL CENTERS OF THE CYCLONE REMAINED 60-90 N MI  
APART, WHICH IS PROBABLY A SIGN THAT IT ISN'T STRENGTHENING. THE  
INITIAL WIND SPEED REMAINS 35 KT BASED ON CONTINUITY, AND HOPEFULLY  
SCATTEROMETER DATA WILL BE AVAILABLE FOR THE NEXT ADVISORY DUE TO  
THE RECENT HIGH BIAS OF THE CONVENTIONAL SATELLITE ESTIMATES.  
 
THE WINDOW FOR STRENGTHENING OF THE TROPICAL CYCLONE IS CLOSING SOON  
DUE TO INCREASING SHEAR AND LIKELY INTRUSIONS OF DRY MID-LEVEL AIR.  
THESE FACTORS SHOULD CAUSE THE STORM TO START A WEAKENING TREND  
SOMETIME TOMORROW. THE LONG-TERM FUTURE OF ROSE DOESN'T LOOK GOLDEN  
EITHER DUE TO FURTHER INCREASING SHEAR FROM AN INCOMING UPPER- LEVEL  
TROUGH. THE NEW FORECAST IS JUST A SHADE LOWER THAN THE PREVIOUS  
ONE, NEAR THE MODEL CONSENSUS, WITH ROSE LIKELY SINKING TO A  
DEPRESSION IN A FEW DAYS AND DEGENERATING TO A REMNANT LOW BY DAY 5.  
 
THE INITIAL MOTION REMAINS NORTHWESTWARD AT ABOUT 14 KT. ROSE IS  
IS LIKELY TO CONTINUE MOVING IN THAT GENERAL DIRECTION DURING  
THE NEXT COUPLE OF DAYS AROUND THE SOUTHWESTERN AND WESTERN  
PERIPHERY OF A STRONG SUBTROPICAL RIDGE. BEYOND THAT TIME,  
GUIDANCE IS COMING INTO GOOD AGREEMENT ON A MID- TO UPPER-LEVEL  
TROUGH OVER THE NORTH-CENTRAL ATLANTIC CAUSING THE CYCLONE TO  
RECURVE TO THE NORTH, NORTHEAST AND EVEN EAST-NORTHEASTWARD BY  
THE WEEKEND. WHILE THE MODELS DON'T AGREE ON HOW SHARP OF A  
TURN WILL OCCUR, THEY ARE AT LEAST CONSISTENT THAT THIS TROUGH  
WILL TAKE THE STORM INTO A HOSTILE ENVIRONMENT AND DECAY. THE NEW  
FORECAST IS AGAIN ADJUSTED WELL TO NORTHEAST AT LONG RANGE, AND  
STILL MIGHT NOT BE FAR ENOUGH TO THE EAST.  
 
 
FORECAST POSITIONS AND MAX WINDS  
 
INIT 20/2100Z 18.4N 34.4W 35 KT 40 MPH  
12H 21/0600Z 20.0N 35.6W 40 KT 45 MPH  
24H 21/1800Z 21.8N 36.7W 35 KT 40 MPH  
36H 22/0600Z 23.3N 37.8W 35 KT 40 MPH  
48H 22/1800Z 24.5N 38.9W 30 KT 35 MPH  
60H 23/0600Z 26.0N 39.9W 30 KT 35 MPH  
72H 23/1800Z 27.3N 40.2W 30 KT 35 MPH  
96H 24/1800Z 29.2N 38.8W 25 KT 30 MPH  
120H 25/1800Z 31.5N 34.5W 25 KT 30 MPH...POST-TROP/REMNT LOW  
 

 
FORECASTER BLAKE  
 
 
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