000
WTPZ44 KNHC 281405
TCDEP4
 
TROPICAL STORM NORMAN DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142012
800 AM PDT FRI SEP 28 2012
 
SATELLITE DATA AND SHIP OBSERVATIONS INDICATE THAT THE LOW
PRESSURE AREA BETWEEN THE WEST COAST OF MAINLAND MEXICO AND BAJA
CALIFORNIA NOW HAS A CLOSED SURFACE CIRCULATION. SHIPS OBSERVATIONS
OF 45 TO 50 KT FROM ELEVATED ANEMOMETERS SUGGEST THAT THE INITIAL
INTENSITY IS AROUND 40 KT...AND ADVISORIES ARE BEING INITIATED ON
TROPICAL STORM NORMAN AT THIS TIME. NORMAN IS SITUATED IN AN
ENVIRONMENT OF 15 TO 20 KT OF SOUTHWESTERLY SHEAR...AS MICROWAVE
IMAGERY INDICATES THAT THE SURFACE CENTER IS DISPLACED ABOUT A
DEGREE TO THE SOUTHWEST OF THE MID-LEVEL CIRCULATION. THIS SHEAR IS
FORECAST BY THE GLOBAL MODELS TO CONTINUE UNTIL THE CENTER MOVES
INLAND...SO THE NHC FORECAST ONLY SHOWS A LITTLE INTENSIFICATION
BEFORE LANDFALL. AFTER THE CENTER MOVES INLAND...QUICK WEAKENING IS
EXPECTED...AND THE CYCLONE IS EXPECTED TO DISSIPATE BY 48 HOURS. 

THE INITIAL MOTION ESTIMATE IS 360/14...AS NORMAN IS SITUATED
BETWEEN A SUBTROPICAL RIDGE CENTERED OVER THE GULF OF MEXICO AND A
MID-LEVEL LOW TO THE WEST. A GENERAL NORTHWARD MOTION IS EXPECTED
DURING THE NEXT DAY OR SO...AND NORMAN IS FORECAST TO MAKE LANDFALL
WITHIN 24 HOURS. AFTER LANDFALL...THE WEAKENING CYCLONE MAY TURN
NORTHWESTWARD BEFORE DISSIPATING. THE NHC FORECAST IS NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE THROUGH LANDFALL.

USERS ARE REMINDED NOT TO FOCUS ON THE EXACT TRACK OF THE
CENTER SINCE NORMAN HAS A LARGE AREA OF TROPICAL-STORM FORCE
WINDS. IN ADDITION...HEAVY RAINFALL AND FLASH FLOODING ARE ALSO
EXPECTED OVER PORTIONS OF THE MEXICAN STATES OF SINALOA AND FAR
WESTERN DURANGO.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/1500Z 22.8N 108.6W   40 KT  45 MPH
 12H  29/0000Z 24.8N 108.8W   45 KT  50 MPH
 24H  29/1200Z 26.5N 109.2W   30 KT  35 MPH...INLAND
 36H  30/0000Z 27.5N 109.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  30/1200Z...DISSIPATED
 
$$
FORECASTER BRENNAN/ROBERTS