000
WTNT45 KNHC 171432
TCDAT5
 
TROPICAL STORM ERIN DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052013
1100 AM AST SAT AUG 17 2013
 
THE CLOUD PATTERN OF ERIN HAS CHANGED LITTLE DURING THE LAST SEVERAL
HOURS. THE LOW-LEVEL CENTER IS EXPOSED TO THE SOUTH OF AN AREA OF
DEEP CONVECTION DUE TO STRONG SOUTHERLY FLOW ALOFT. THE INITIAL
WIND SPEED IS HELD AT 35 KT...A LITTLE HIGHER THAN THE DVORAK
CLASSIFICATIONS. ERIN IS STILL OVER 25-26C WATERS...AND ALTHOUGH THE
SSTS INCREASE ALONG THE FORECAST TRACK...THE CONTINUED IMPACT OF
DRY STABLE AIR COMBINED WITH EVEN STRONGER SHEAR SHOULD CAUSE THE
CYCLONE TO SLOWLY WEAKEN. THE NHC FORECAST SHOWS ERIN DEGENERATING
TO A REMNANT LOW BY DAY 4 AND DISSIPATING BY DAY 5...HOWEVER...THIS
CERTAINLY COULD OCCUR SOONER AS SHOWN BY AT LEAST A FEW MODELS.
 
VISIBLE SATELLITE IMAGES INDICATE THAT ERIN HAS JOGGED TO THE NORTH
DURING THE LAST 6 HOURS. A SMOOTHED INITIAL MOTION ESTIMATE IS
315/10. A TURN TO THE LEFT...OR WEST-NORTHWEST...IS EXPECTED
TO BEGIN LATER TODAY AND PERSIST THROUGH MONDAY WHILE A SUBTROPICAL
RIDGE BECOMES MORE ESTABLISHED TO THE NORTH OF THE STORM. IF ERIN
SURVIVES BEYOND A FEW DAYS...IT WILL LIKELY TURN BACK TO THE
NORTHWEST TOWARD ANOTHER WEAKNESS IN THE RIDGE. THE NHC TRACK
FORECAST HAS BEEN ADJUSTED NORTHWARD...MAINLY TO ACCOUNT FOR THE
INITIAL POSITION.

FORECAST POSITIONS AND MAX WINDS
 
INIT  17/1500Z 19.8N  35.7W   35 KT  40 MPH
 12H  18/0000Z 20.5N  37.2W   35 KT  40 MPH
 24H  18/1200Z 21.1N  39.0W   30 KT  35 MPH
 36H  19/0000Z 21.8N  41.0W   30 KT  35 MPH
 48H  19/1200Z 22.6N  43.4W   30 KT  35 MPH
 72H  20/1200Z 25.0N  47.8W   30 KT  35 MPH
 96H  21/1200Z 28.5N  50.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  22/1200Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI