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HURRICANE GREG DISCUSSION NUMBER   6
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT MON SEP 06 1999
 
SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 65 KT...SO GREG
IS UPGRADED TO A MINIMAL HURRICANE. AT LEAST A PARTIAL EYE HAS BEEN
PRESENT ON THE LOS CABOS RADAR DURING THE DAY. THAT BEING SAID...THE
SYSTEM IS GIVING THE APPEARANCE OF BEING SHEARED. THERE IS NO
OUTFLOW TO THE NORTHEAST SIDE...AND SOME OF THE LOW CLOUD LINES
NORTHEAST OF THE EYE ARE EXPOSED. WATER VAPOR IMAGERY AND VERTICAL
SHEAR ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN SUGGEST
LESS THAN 20 KT OF SHEAR...SO THE RAGGED APPEARANCE IS A BIT
PUZZLING. THE INTENSITY FORECAST CALLS FOR A LITTLE MORE
INTENSIFICATION BEFORE GREG HITS COOLER WATER...FOLLOWED BY STEADY
WEAKENING. 

THE MOTION HAS BEEN A LITTLE ERRATIC AT TIMES...BUT IS ESTIMATED TO
BE 305/6. THE SYNOPTIC PATTERN HAS NOT CHANGED FROM SIX HOURS
AGO...WITH RIDGING OVER NORTHWEST MEXICO NORTH OF GREG AND AN UPPER
LEVEL LOW NEAR 29N125W. THIS WOULD SUGGEST A CONTINUED WEST-
NORTHWEST TO NORTHWEST MOTION. HOWEVER...THE TRACK FORECAST GUIDANCE
IS QUITE DIVERSE...WITH FORECASTS RANGING FROM STRAIGHT NORTHWEST TO
A TURN TO THE WEST-SOUTHWEST. THE SPEEDS ARE ALSO DIVERSE...WITH THE
GFDL...NOGAPS...UKMET..AND AVN BEING VERY SLOW AND THE OTHER
GUIDANCE BEING FASTER. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE
PREVIOUS PACKAGE...EXCEPT AT 72 HOURS WHERE IT IS SHIFTED TO THE
SOUTH. IT IS DOWN THE MIDDLE OF THE GUIDANCE IN TERMS OF BOTH
DIRECTION AND SPEED.
 
BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     06/2100Z 21.7N 108.7W    65 KTS
12HR VT     07/0600Z 22.2N 109.5W    70 KTS
24HR VT     07/1800Z 22.8N 110.7W    65 KTS
36HR VT     08/0600Z 23.2N 111.9W    55 KTS
48HR VT     08/1800Z 23.5N 113.5W    40 KTS
72HR VT     09/1800Z 24.0N 116.5W    30 KTS
 
 
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