000
WTPZ44 KNHC 072043
TCDEP4
 
TROPICAL STORM NARDA DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142013
200 PM PDT MON OCT 07 2013
 
AFTER INCREASING IN ORGANIZATION RAPIDLY OVERNIGHT...NARDA APPEARS
TO HAVE ENTERED A PERIOD OF ARRESTED DEVELOPMENT. WHILE A 1625 UTC
SSMI/S PASS SHOWS THAT THE INNER CORE STRUCTURE OF THE CYCLONE HAS
CHANGED LITTLE SINCE EARLIER THIS MORNING...CLOUD TOP TEMPERATURES
HAVE WARMED CONSIDERABLY WITH THE APPROACH OF THE DIURNAL
CONVECTIVE MINIMUM. SINCE THE OVERALL ORGANIZATION OF THE CYCLONE
HAS NOT BEEN DEGRADED...THE INITIAL INTENSITY HELD AT 55 KT IN
ACCORDANCE WITH TAFB AND SAB SATELLITE INTENSITY ESTIMATES.

SATELLITE FIXES DURING THE LAST SEVERAL HOURS HAVE BEEN IN EXCELLENT
AGREEMENT...AND MAKE THE INITIAL MOTION ESTIMATE A FAIRLY CONFIDENT
285/13. NARDA SHOULD CONTINUE TO MOVE WEST-NORTHWESTWARD AT A
SLOWER FORWARD SPEED DURING THE NEXT COUPLE OF DAYS WHILE IT NEARS
THE WESTERN EDGE OF A MID-LEVEL RIDGE EXTENDING WESTWARD FROM
MEXICO.  AFTER THAT...THERE HAS BEEN A SIGNIFICANT SHIFT IN THE
GUIDANCE...WITH THE GFS AND ECMWF NOW IN AGREEMENT THAT AN
AMPLIFIED MID-LEVEL TROUGH NEAR THE U.S. WEST COAST WILL HAVE LESS
EFFECT ON NARDA WHILE IT WEAKENS CONSIDERABLY AND BECOMES A
SHALLOWER SYSTEM. THE NHC OFFICIAL TRACK FORECAST HAS BEEN SHIFTED
TO THE LEFT AFTER 36 HOURS AND IS MUCH FASTER LATER IN THE FORECAST
PERIOD...TO BETTER MATCH THE LATEST MULTI-MODEL CONSENSUS TVCE.

NARDA SHOULD BE MOVING OVER WARM BUT GRADUALLY DECREASING SEA
SURFACE TEMPERATURES WHILE IT PASSES UNDERNEATH AN UPPER-LEVEL
RIDGE AXIS DURING THE NEXT 24 TO 36 HOURS.  EXCEPT FOR THE PROXIMITY
OF A SOMEWHAT DRIER AND MORE STABLE AIR MASS LURKING TO THE
NORTHWEST...THESE FAVORABLE ENVIRONMENTAL FACTORS SHOULD ALLOW
NARDA TO INTENSIFY INTO A HURRICANE WITHIN A DAY OR SO.  AFTER A
COUPLE OF DAYS...INCREASING WESTERLY SHEAR ASSOCIATED WITH THE U.S.
WEST COAST TROUGH AND COOLER WATERS SHOULD RESULT IN WEAKENING...
WITH THE SHEAR BECOMING QUITE STRONG AND LIKELY CAUSING NARDA TO
DEGENERATE INTO A REMNANT LOW BY DAY 5...IF NOT SOONER.  THE NHC
INTENSITY FORECAST HAS BEEN LOWERED A BIT COMPARED TO THE PREVIOUS
FORECAST AND IS CLOSE TO THE SHIPS/LGEM...BUT HIGHER THAN THE
REGIONAL DYNAMICAL MODELS.

FORECAST POSITIONS AND MAX WINDS
 
INIT  07/2100Z 14.4N 123.7W   55 KT  65 MPH
 12H  08/0600Z 14.8N 125.3W   60 KT  70 MPH
 24H  08/1800Z 15.4N 127.2W   65 KT  75 MPH
 36H  09/0600Z 15.8N 128.6W   70 KT  80 MPH
 48H  09/1800Z 16.0N 129.5W   65 KT  75 MPH
 72H  10/1800Z 16.0N 130.5W   50 KT  60 MPH
 96H  11/1800Z 16.0N 132.0W   35 KT  40 MPH
120H  12/1800Z 16.0N 134.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER KIMBERLAIN