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TROPICAL STORM LORENA DISCUSSION NUMBER  10
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT THU OCT 04 2001

MULTISPECTRAL IR IMAGERY INDICATES THAT THE CENTER OF LORENA IS
AND EXPOSED SWIRL OF LOW CLOUDS WELL REMOVED FROM ANY CONVECTION.
THE INITIAL INTENSITY IS A BIT OF AN UNKNOWN.  EARLIER RECON AND
SATELLITE MICROWAVE DATA DID NOT CONCLUSIVELY SHOW ANY TROPICAL
STORM WINDS IN THE CIRCULATION.  HOWEVER...SATELLITE INTENSITY
ESTIMATES...BASED MAINLY ON RULES FOR WEAKENING SYSTEMS...ARE STILL
AT TROPICAL STORM STRENGTH.  THE INITIAL INTENSITY WILL REMAIN
35 KT FOR THIS PACKAGE IN DEFERENCE TO THE POSSIBILITY THAT SOME
TROPICAL STORM WINDS MAY BE OCCURRING IN THE CONVECTION WELL TO
THE EAST OF THE CENTER.  MICROWAVE DATA LATER IN THE DAY MAY HELP
DETERMINE IF LORENA HAS ACTUALLY WEAKENED TO A DEPRESSION.
 
THE INITIAL MOTION IS 350/7.  DEEP-LAYER TROUGHING OVER BAJA
CALIFORNIA SHOULD MOVE LORENA ALONG A NORTHWARD AND THEN
NORTHEASTWARD MOTION...AND THIS IS REFLECTED BY MOST OF THE NHC
HURRICANE GUIDANCE.  THE NEW FORECAST TRACK IS IN BEST AGREEMENT
WITH THE BAMS...CALLING FOR LANDFALL ON THE WEST COAST OF MEXICO
IN ABOUT 36 HR.  IT SHOULD BE NOTED THAT WHILE CLIPER AND THE UKMET
WANT TO MOVE LORENA CLOSER TO SOUTHERN BAJA CALIFORNIA THAN THE
OTHER MODELS...THE CYCLONE WOULD LIKELY DIE BEFORE IT COULD BECOME
A SERIOUS THREAT TO THAT AREA.
 
REGARDLESS OF THE EXACT INITIAL INTENSITY OF LORENA...IT WILL NOT
BE A TROPICAL STORM MUCH LONGER.  THE CIRCULATION IS VERY SHALLOW...
AND THE CENTER IS EMBEDDED IN AN AREA OF DRY AIR ALOFT AND
INCREASING VERTICAL SHEAR.  THE INTENSITY FORECAST CALLS FOR
CONTINUED WEAKENING UNTIL LANDFALL...WITH DISSIPATION OVER THE 
MOUNTAINS OF MEXICO THEREAFTER.

RAINFALL IS THE MAJOR THREAT FROM LORENA.  SATELLITE IMAGERY SHOWS
DEEP LAYER MOISTURE AND SOUTHWESTERLY FLOW ASSOCIATED WITH THE
CONVECTION EAST OF THE CENTER...AND THIS SHOULD SPREAD NORTHWARD
OVER THE NEXT DAY OR TWO AS THE CENTER APPROACHES THE COAST.  THERE 
IS A CHANCE THIS MOISTURE MAY INTERACT WITH A JET STREAM OVER
NORTHERN MEXICO...POSSIBLY PRODUCING HEAVY RAINS OVER CENTRAL AND
NORTHERN MEXICO EVEN AFTER LORENA DISSIPATES.

FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     04/0900Z 17.9N 107.1W    35 KTS
12HR VT     04/1800Z 19.1N 107.0W    30 KTS
24HR VT     05/0600Z 20.6N 106.4W    25 KTS
36HR VT     05/1800Z 22.0N 105.7W    25 KTS
48HR VT     06/0600Z 23.4N 104.9W    20 KTS...INLAND AND DISSIPATING
72HR VT     07/0600Z...DISSIPATED
 
 
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