000
WTPZ42 KNHC 310838
TCDEP2
 
TROPICAL STORM GIL DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072013
200 AM PDT WED JUL 31 2013
 
GIL CONTINUES TO BECOME BETTER ORGANIZED...WITH MICROWAVE IMAGERY
SHOWING A WELL-DEFINED CONVECTIVE BAND WRAPPING AT LEAST 3/4 OF THE
WAY AROUND THE CENTER.  DVORAK ESTIMATES HAVE INCREASED TO T3.0
FROM TAFB AND THE OBJECTIVE UW-CIMSS ADT...WARRANTING AN INITIAL
INTENSITY OF 45 KT.  NEGLIGIBLE DEEP-LAYER SHEAR...WARM SSTS...AND
A MOIST ENVIRONMENT FAVOR STRENGTHENING FOR THE NEXT COUPLE OF
DAYS.  IN THE LATTER PART OF THE FORECAST PERIOD...GIL COULD BEGIN
TO INGEST A LITTLE MORE STABLE AIR...AND VERTICAL SHEAR WILL LIKELY
BEGIN TO INCREASE.  THE NHC INTENSITY FORECAST IS CLOSE TO A BLEND
OF THE SHIPS AND LGEM MODELS...SHOWING GIL REACHING HURRICANE
STATUS IN 36 HOURS AND THEN WEAKENING ON DAYS 3 THROUGH 5.

THE INITIAL MOTION REMAINS 285/13 KT.  STRONG MID-LEVEL RIDGING
EXTENDING FROM THE SOUTHWESTERN U.S. AND NORTHERN MEXICO WESTWARD
INTO THE EASTERN PACIFIC WILL CONTINUE TO FORCE GIL WESTWARD TO
WEST-NORTHWESTWARD FOR THE ENTIRE FORECAST PERIOD.  HOWEVER...THE
RIDGE WILL BE WEAKENING DURING THE NEXT 2 TO 3 DAYS...AND GIL
SHOULD RESPOND BY SLOWING DOWN CONSIDERABLY FROM DAY 3 THROUGH 5. 
THE TRACK GUIDANCE ENVELOPE IS BOUNDED BY THE STRONGER GFS SOLUTION
ON THE NORTHERN EDGE AND THE WEAKER ECMWF SOLUTION ON THE SOUTHERN
EDGE...AND THE ENTIRE SUITE OF MODELS HAS SHIFTED A BIT TO THE
SOUTH ON THIS CYCLE.  THE OFFICIAL TRACK FORECAST IS ALSO NUDGED
SOUTHWARD...ENDING UP CLOSE TO THE MULTI-MODEL CONSENSUS TVCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  31/0900Z 13.3N 118.9W   45 KT  50 MPH
 12H  31/1800Z 13.8N 120.8W   55 KT  65 MPH
 24H  01/0600Z 14.4N 123.0W   60 KT  70 MPH
 36H  01/1800Z 14.8N 125.1W   65 KT  75 MPH
 48H  02/0600Z 15.2N 127.1W   65 KT  75 MPH
 72H  03/0600Z 15.7N 130.4W   60 KT  70 MPH
 96H  04/0600Z 16.0N 133.5W   50 KT  60 MPH
120H  05/0600Z 16.0N 137.0W   35 KT  40 MPH
 
$$
FORECASTER BERG