Tropical Storm NARDA

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TROPICAL STORM NARDA DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142013
200 AM PDT MON OCT 07 2013
 
RECENT MICROWAVE IMAGES INDICATE THAT NARDA HAS BEEN GETTING MORE
ORGANIZED.  A LONG CURVED BAND WRAPS AROUND THE WESTERN SIDE OF THE
CIRCULATION AND CONNECTS TO AN INNER RING OF CONVECTION THAT IS
OPEN TO THE NORTH OF THE CENTER.  THE INITIAL INTENSITY IS RAISED
TO 40 KT BASED ON DVORAK ESTIMATES OF T3.0/45 KT FROM TAFB AND
T2.5/35 KT FROM SAB...AS WELL AS ADT AND AMSU ESTIMATES NEAR 40 KT. 
EASTERLY SHEAR IS GRADUALLY DIMINISHING AND SHOULD FALL BELOW 10 KT
DURING THE NEXT 24 HOURS AS NARDA MOVES BENEATH AN UPPER-LEVEL
RIDGE.  OCEAN WATERS ARE PLENTY WARM AT AROUND 28C...AND THE
STRUCTURE OF THE CYCLONE FAVORS CONTINUED STRENGTHENING FOR THE NEXT
2 TO 3 DAYS.  GIVEN THESE FACTORS...THE NHC INTENSITY FORECAST
GENERALLY FOLLOWS THE STATISTICAL MODELS...WHICH LIE AT THE UPPER
RANGE OF THE GUIDANCE...AND SHOWS FASTER STRENGTHENING THAN
INDICATED IN THE PREVIOUS ADVISORY FOR THE FIRST 48 HOURS. 
THEREAFTER...INCREASING VERTICAL SHEAR AND DRY STABLE AIR SHOULD
CAUSE NARDA TO WEAKEN BY DAYS 4 AND 5.

THE INITIAL MOTION IS 275/12 KT.  NARDA IS LOCATED TO THE SOUTH OF A
MID-LEVEL RIDGE THAT SHOULD STEER THE CYCLONE ON THIS TRAJECTORY
FOR THE NEXT 36 HOURS OR SO.  AFTER THAT TIME...THE STEERING PATTERN
IS FORECAST TO COLLAPSE DUE TO A MID- TO UPPER-LEVEL TROUGH THAT
WILL BE DIGGING SOUTHEASTWARD ACROSS THE U.S. WEST COAST...CAUSING
NARDA TO SLOW TO A CRAWL BEGINNING IN 72 HOURS AND LASTING THROUGH
THE END OF THE FORECAST PERIOD.  THERE IS SOME SIGNIFICANT SPREAD
AMONG THE TRACK GUIDANCE LATER IN THE PERIOD.  THE GFS MAINTAINS A
STRONGER CYCLONE THAT GETS PULLED NORTHWARD BY THE AMPLIFYING
TROUGH WHILE THE ECMWF SHOWS A WEAKER SYSTEM BEING ADVECTED MORE
QUICKLY TO THE WEST BY THE LOW-LEVEL FLOW.  GIVEN THE
UNCERTAINTY...THE NHC TRACK FORECAST SHOWS ONLY SLOW MOTION BETWEEN
DAYS 3 THROUGH 5.  THIS SOLUTION IS A LITTLE FASTER THAN THE
MULTI-MODEL CONSENSUS TVCE AND VERY CLOSE TO THE NOAA FIM MODEL.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/0900Z 13.2N 120.9W   40 KT  45 MPH
 12H  07/1800Z 13.6N 122.6W   50 KT  60 MPH
 24H  08/0600Z 14.2N 124.6W   60 KT  70 MPH
 36H  08/1800Z 15.0N 126.5W   65 KT  75 MPH
 48H  09/0600Z 15.5N 127.9W   70 KT  80 MPH
 72H  10/0600Z 15.7N 129.2W   65 KT  75 MPH
 96H  11/0600Z 15.8N 130.0W   50 KT  60 MPH
120H  12/0600Z 15.9N 130.9W   35 KT  40 MPH...POST-TROPICAL
 
$$
FORECASTER BERG
 
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