000
WTPZ41 KNHC 240832
TCDEP1
TROPICAL STORM JULIO DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP112008
200 AM PDT SUN AUG 24 2008

ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN INDICATE THAT
JULIO IS EXPERIENCING ABOUT 20 KT OF EASTERLY VERTICAL WIND SHEAR. 
THIS HAS RESULTED IN A PARTLY EXPOSED LOW-LEVEL CENTER JUST TO THE
EAST OF THE MAIN CONVECTIVE MASS.  SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB ARE 45 KT AND 35 KT RESPECTIVELY...WHILE A
QUIKSCAT PASS AT 0135 UTC SHOWED NO RELIABLE WINDS ABOVE 35 KT. 
BASED ON THIS AND THE RELATIVELY UNCHANGED SATELLITE APPEARANCE
SINCE THAT TIME...THE INITIAL INTENSITY REMAINS 35 KT.

THE INITIAL MOTION IS 330/12.  JULIO IS ON THE WEST SIDE OF A
MID/UPPER-LEVEL RIDGE OVER NORTHERN MEXICO AND HEADING FOR A
WEAKNESS IN THE RIDGE SEEN IN WATER VAPOR IMAGERY OVER NORTHERN
BAJA CALIFORNIA.  THE TRACK GUIDANCE MODELS FORECAST JULIO TO MOVE
GENERALLY NORTH-NORTHWESTWARD THROUGH THE FORECAST PERIOD IN
RESPONSE TO THIS PATTERN...WITH THE GUIDANCE CLUSTERED AROUND A
TRACK NEAR OR OVER THE BAJA CALIFORNIA PENINSULA.  THE NEW FORECAST
TRACK IS SHIFTED A LITTLE TO THE LEFT OF THE PREVIOUS TRACK BASED
ON THE CURRENT POSITION AND MOTION...AND IT IS IN BEST AGREEMENT
WITH THE GFDL MODEL.  IT SHOULD BE NOTED THAT THE GFS...UKMET...AND
ECMWF SUGGEST THE POSSIBILITY OF ERRATIC MOTION NEAR THE END OF THE
FORECAST PERIOD.  HOWEVER...THERE MAY NOT BE MUCH LEFT OF JULIO BY
THAT TIME.
 
THE LARGE-SCALE MODELS FORECAST THE UPPER-LEVEL RIDGE TO SHIFT
WESTWARD...WITH JULIO PASSING ON THE RIDGE AXIS IN ABOUT 24 HOURS. 
THE RESULTING DECREASE IN SHEAR SHOULD ALLOW SOME INTENSIFICATION
AS LONG AS THE CENTER IS OVER WARM WATER OR NOT OVER LAND.  AFTER
48 HOURS...JULIO IS LIKELY TO ENCOUNTER STRONG WESTERLY SHEAR...
WHICH SHOULD AT LEAST PREVENT INTENSIFICATION EVEN IF THE CENTER
EMERGES OVER THE GULF OF CALIFORNIA.  THE NEW INTENSITY FORECAST IS
ESSENTIALLY AN UPDATE OF THE PREVIOUS PACKAGE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0900Z 21.5N 109.6W    35 KT
 12HR VT     24/1800Z 22.7N 110.2W    45 KT
 24HR VT     25/0600Z 24.1N 111.1W    45 KT
 36HR VT     25/1800Z 25.5N 112.1W    40 KT...INLAND
 48HR VT     26/0600Z 26.7N 112.7W    35 KT...INLAND
 72HR VT     27/0600Z 28.5N 113.5W    25 KT...INLAND
 96HR VT     28/0600Z 30.5N 114.5W    20 KT...OVER WATER REMNANT LOW
120HR VT     29/0600Z...DISSIPATED
 
$$
FORECASTER BEVEN