HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM BRET DISCUSSION NUMBER   8
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT FRI AUG 20 1999
 
THE LATEST FIX FROM THE AIR FORCE RESERVE HURRICANE HUNTER SHOWS
BRET TO BE NORTH OF THE PREVIOUS FIXES. THE MINIMUM PRESSURE HAS
DROPPED TO 993 MB WITH 850 MB FLIGHT LEVEL WINDS OF 55 KT LESS THAN
10 NM FROM THE CENTER. THE MAXIMUM WINDS ARE SET TO 50 KT FOR THIS
ADVISORY.

BASED ON THE AIRCRAFT DATA...THE INITIAL MOTION IS 360/06. WATER
VAPOR IMAGERY AND LARGE SCALE MODEL GUIDANCE INDICATES AN UPPER
TROUGH OVER SOUTH TEXAS AND NORTHEAST MEXICO OVERLYING A LOW/MID
LEVEL RIDGE THROUGH THE FORECAST PERIOD. NHC HURRICANE GUIDANCE IS
SCATTERED. THE NHC98 AND CLIPER...THE BEST VERIFYING ON THE CURRENT
NORTHWARD MOTION...CONTINUE A SLOW NORTHWARD MOTION THROUGH 48
HOURS. THE BAM MODELS...LBAR...AND NHC90UK ALL TURN THE STORM
WESTWARD TOWARD THE MEXICAN COAST. THE GFDL...WHICH HAS HAD PROBLEMS
WITH RUN-TO-RUN CONSISTENCY...TURNS BRET BACK TO THE SOUTHWEST. THE
OFFICIAL FORECAST TRACK IS A BLEND OF THE CURRENT MOTION AND A LATER
NORTHWESTWARD TURN...AND IS SHIFTED NORTH OF THE PREVIOUS PACKAGE.

AN UPPER LEVEL RIDGE OVER BRET IS PROVIDING GOOD OUTFLOW WITH LIGHT
SHEAR. THE SHIPS MODEL BRINGS THE CYCLONE TO HURRICANE STRENGTH IN
LESS THAN 24 HOURS AND TO 90 KT IN 48 HOURS. THE INTENSITY FORECAST
IS A LITTLE MORE CONSERVATIVE...BUT STILL MAKES BRET A HURRICANE IN
LESS THAN 24 HOURS.

WITH THE CURRENTLY NORTHERLY MOTION AND THE UNCERTAINTY IN THE
FORECAST...ALL INTERESTS ALONG THE TEXAS COAST SHOULD MONITOR THE
PROGRESS OF BRET OVER THE WEEKEND.
 
BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     20/1500Z 20.9N  94.6W    55 KTS
12HR VT     21/0000Z 21.6N  94.7W    60 KTS
24HR VT     21/1200Z 22.3N  95.1W    70 KTS
36HR VT     22/0000Z 23.0N  95.6W    75 KTS
48HR VT     22/1200Z 23.5N  96.5W    80 KTS
72HR VT     23/1200Z 24.0N  98.5W    65 KTS
 
 
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