000
WTPZ42 KNHC 052046
TCDEP2
 
TROPICAL STORM LORENA DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP122013
200 PM PDT THU SEP 05 2013

VISIBLE IMAGERY HAS NOT BEEN AS HELPFUL AS IT USUALLY IS IN LOCATING
THE CENTER THIS AFTERNOON WITH A LARGE CONVECTIVE BURST OBSCURING
THE CIRCULATION FEATURES.  ASCAT DATA SUGGEST THE CENTER IS A BIT
ELONGATED...AND THE INITIAL POSITION IS RELOCATED NORTHWARD...
CLOSER TO A CENTER INDICATED ON MICROWAVE PASSES.  STILL...THE
SURFACE CENTER APPEARS TO BE DISPLACED A FAIR DISTANCE SOUTHWEST OF
THE MAIN CONVECTIVE MASS.  THE INITIAL INTENSITY IS SET TO 35
KT...IN AGREEMENT WITH THE ASCAT AND THE LATEST DVORAK ESTIMATES.  
 
THE INITIAL STRUCTURE OF THE CYCLONE WOULD NOT SEEM TO FAVOR RAPID
INTENSIFICATION...BUT WITH LIGHT SHEAR AND WARM WATERS...SOME
STRENGTHENING SEEMS PROBABLE DURING THE NEXT 36H OR SO. LAND
INTERACTION AND COOLER WATERS SHOULD CAUSE LORENA TO WEAKEN AFTER
THAT TIME.  THE NHC INTENSITY FORECAST IS A BIT HIGHER THAN THE
PREVIOUS ONE...BUT IS STAYING ON THE CONSERVATIVE SIDE OF THE
GUIDANCE PLUME...GIVING SOME WEIGHT TO THE GLOBAL MODELS WHICH
GENERALLY DO NOT SHOW MUCH STRENGTHENING.  

RECENTLY LORENA HAS BEEN MOVING TO THE NORTH-NORTHWEST...PERHAPS DUE
TO A MID/UPPER-LEVEL LOW OVER NORTHWESTERN MEXICO TEMPORARILY
WEAKENING THE RIDGE.  A LONG-TERM MOTION IS 325/10...NOTABLY TO THE
RIGHT OF THE PREVIOUS ESTIMATE.  THE LOW SHOULD MOVE FARTHER AWAY
FROM LORENA...ALLOWING THE STORM TO TURN MORE TO THE NORTHWEST
TOWARD THE BAJA CALIFORNIA PENINSULA.  MODEL GUIDANCE CONTINUES TO
TREND A BIT FASTER AND NORTHWARD...AND THE NHC FORECAST IS SHIFTED
IN THAT WAY.
 
A TROPICAL STORM WARNING WILL LIKELY BE REQUIRED FOR THE SOUTHERN
PART OF BAJA CALIFORNIA SUR LATER TONIGHT.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  05/2100Z 19.2N 106.6W   35 KT  40 MPH
 12H  06/0600Z 20.3N 107.7W   40 KT  45 MPH
 24H  06/1800Z 21.6N 108.9W   45 KT  50 MPH
 36H  07/0600Z 22.5N 109.7W   45 KT  50 MPH
 48H  07/1800Z 23.3N 110.3W   40 KT  45 MPH
 72H  08/1800Z 24.5N 110.7W   30 KT  35 MPH
 96H  09/1800Z 26.0N 111.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  10/1800Z...DISSIPATED
 
$$
FORECASTER BLAKE