Tropical Storm IVO

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TROPICAL STORM IVO DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092013
800 PM PDT FRI AUG 23 2013
 
THE CLOUD PATTERN HAS NOT BECOME ANY BETTER ORGANIZED DURING THE
PAST FEW HOURS...AND IVO STILL CONSISTS OF A LARGE CIRCULATION
DEVOID OF AN INNER CORE. IN FACT...THE CENTER OF CIRCULATION OR THE
AREA OF MINIMUM PRESSURE HAS BEEN PIVOTING WITHIN A LARGER CYCLONIC
GYRE. IN ADDITION...THE AREA OF DEEP CONVECTION IS CURRENTLY
DIMINISHING...AND THERE IS LITTLE THUNDERSTORM ACTIVITY NEAR THE
ESTIMATED CENTER. ALTHOUGH THE SUBJECTIVE AND OBJECTIVE DVORAK
ESTIMATES SUGGEST LOWER WINDS...EARLIER ASCAT DATA AS WELL AS SHIP
REPORTS SUGGEST THAT THE MAXIMUM WINDS ARE STILL 40 KNOTS. THESE
STRONG WINDS ARE WELL REMOVED FROM THE CENTER. IVO HAS A SMALL
OPPORTUNITY TO STRENGTHEN SLIGHTLY BEFORE THE CYCLONE MOVES OVER
COOLER WATERS IN ABOUT 24 HOURS OR SOONER.  

SINCE THE CENTER HAS BEEN REFORMING WITHIN THE LARGE GYRE...THE
INITIAL MOTION IS HIGHLY UNCERTAIN. IT APPEARS...HOWEVER...THAT THE
CYCLONE IS MOVING NORTHWARD OR 350 DEGREES AT 10 KNOTS...A LITTLE
FASTER THAN EARLIER TODAY. IVO CONTINUES TO BE LOCATED ON THE
WESTERN EDGE OF A MID-LEVEL RIDGE AND IS HEADING TOWARD A WEAKNESS
INDUCED BY AN AMPLIFYING TROUGH TO THE NORTHWEST. THIS PATTERN
SHOULD CONTINUE TO STEER IVO NORTH-NORTHWESTWARD UNTIL THE CYCLONE
WEAKENS...BECOMES SHALLOW...AND THEN BEGINS TO MEANDER WITHIN THE
LOW-LEVEL FLOW IN ABOUT 3 TO 4 DAYS. MOST OF THE TRACK GUIDANCE IS
CONSISTENT WITH THE NORTH-NORTHWEST TRACK FOR THE NEXT 24 TO 36
HOURS. AFTER THAT TIME...THE SPREAD IN THE GUIDANCE IS QUITE LARGE
WITH SOME MODELS SHOWING A NORTHWARD TRACK AND OTHERS A TURN TO THE
SOUTHWEST. THE LATTER SCENARIO...WHICH INCLUDE THE ECMWF...IS
PROBABLY THE RESULT OF THE MODELS ASSUMING IVO TO BE A MUCH WEAKER
AND SHALLOW CYCLONE. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0300Z 20.7N 112.0W   40 KT  45 MPH
 12H  24/1200Z 22.1N 112.4W   45 KT  50 MPH
 24H  25/0000Z 23.8N 113.0W   45 KT  50 MPH
 36H  25/1200Z 25.5N 114.0W   40 KT  45 MPH
 48H  26/0000Z 26.5N 114.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  27/0000Z 28.0N 116.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  28/0000Z 28.0N 116.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  29/0000Z...DISSIPATED
 
$$
FORECASTER AVILA
 
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