000
WTPZ44 KNHC 070236
TCDEP4
 
TROPICAL STORM NARDA DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142013
800 PM PDT SUN OCT 06 2013
 
DEEP CONVECTION ASSOCIATED WITH THE CYCLONE HAS BEEN INCREASING NEAR
THE CENTER AND IN A CURVED BAND OVER THE WESTERN PORTION OF THE
CIRCULATION DURING THE LAST SEVERAL HOURS. SATELLITE INTENSITY
ESTIMATES HAVE NUDGED UPWARD...AND THE INITIAL INTENSITY IS SET AT
35 KT IN ACCORDANCE WITH A DVORAK CLASSIFICATION FROM TAFB AND A
CIRA AMSU ESTIMATE. THIS MAKES THE CYCLONE TROPICAL STORM NARDA.
THE ATMOSPHERIC CONDITIONS ARE EXPECTED TO BE GENERALLY FAVORABLE
FOR STRENGTHENING DURING THE NEXT FEW DAYS...WITH THE SHEAR
FORECAST TO BECOME QUITE LOW BY 48 HOURS WHILE NARDA REMAINS OVER
WARM WATER. BEYOND 72 HOURS...A CONSIDERABLE INCREASE IN
SOUTHWESTERLY SHEAR...DRIER AIR...AND SLIGHTLY COOLER WATER SHOULD
PROMOTE WEAKENING. THE NHC INTENSITY FORECAST IS A LITTLE HIGHER
THAN THE PREVIOUS ONE AND MORE OR LESS IN LINE WITH THE INTENSITY
MODEL CONSENSUS.
 
NARDA IS MOVING WESTWARD AT ABOUT 11 KT ON THE SOUTH SIDE OF A
MID-LEVEL RIDGE LOCATED OVER NORTHWESTERN MEXICO AND THE
SOUTHWESTERN UNITED STATES. THIS RIDGE IS ANTICIPATED TO WEAKEN AND
SHIFT EASTWARD DURING THE NEXT COUPLE OF DAYS...CAUSING NARDA TO
SLOW DOWN A LITTLE AND TURN WEST-NORTHWESTWARD. THE MODELS BECOME
QUITE DIVERGENT IN ABOUT 3 DAYS WHEN THE STORM MOVES INTO A REGION
OF WEAK STEERING FLOW BETWEEN A TROUGH TO ITS NORTH AND RIDGES TO
ITS EAST AND WEST. THE GFDL AND HWRF MODELS SHOW NARDA BEING PICKED
UP BY THE TROUGH...WHILE THE GFS...ECMWF...AND FIM SHOW THE SYSTEM
STALLING AND THEN TURNING BACK TOWARD THE WEST TO THE SOUTH OF A
BUILDING LOW- TO MID-LEVEL RIDGE. THE LATTER SOLUTION IS
PREFERRED...AND THE OFFICIAL FORECAST IS NEAR THE CONSENSUS OF
THOSE MODELS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/0300Z 13.2N 119.8W   35 KT  40 MPH
 12H  07/1200Z 13.5N 121.6W   40 KT  45 MPH
 24H  08/0000Z 14.0N 123.6W   45 KT  50 MPH
 36H  08/1200Z 14.8N 125.3W   55 KT  65 MPH
 48H  09/0000Z 15.5N 126.6W   65 KT  75 MPH
 72H  10/0000Z 16.1N 127.7W   65 KT  75 MPH
 96H  11/0000Z 16.4N 128.3W   50 KT  60 MPH
120H  12/0000Z 16.7N 129.0W   35 KT  40 MPH...POST-TROPICAL
 
$$
FORECASTER CANGIALOSI