HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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HURRICANE BRET DISCUSSION NUMBER  15
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT SUN AUG 22 1999

LATEST REPORTS FROM THE HURRICANE HUNTERS SUGGEST THAT BRET MAY HAVE
STRENGTHENED A LITTLE FURTHER...WITH THE DROPSONDE-MEASURED CENTRAL
PRESSURE DOWN TO 948 MB.  BRETS APPEARANCE ON SATELLITE IMAGERY IS
NOT AS SYMMETRIC AS IT WAS EARLIER.  AN UPPER-LEVEL TROUGH JUST TO
THE WEST OF THE HURRICANE MAY BE CAUSING SOME EROSION OF THE CLOUD
SHIELD OVER THE WESTERN SEMICIRCLE.  NOTWITHSTANDING...THE INNER
CORE OF BRET APPEARS TO BE UNAFFECTED.  SOME FLUCTUATIONS IN
INTENSITY MAY OCCUR BUT CATEGORY FOUR INTENSITY IS FORECAST TO BE
MAINTAINED UNTIL LANDFALL.

WATER VAPOR IMAGERY SUGGESTS A MID-TROPOSPHERIC CYCLONIC VORTEX NEAR
THE LOWER RIO GRANDE...AND THIS MAY HAVE PUSHED THE HURRICANE A
LITTLE MORE NORTHWARD THAN WAS EXPECTED. CENTER FIXES NOW INDICATE A
NORTHWESTWARD MOTION NEAR 9 KNOTS.  THERE WAS AN EXTENSIVE SAMPLING
OF THE STEERING ENVIRONMENT AROUND BRET AND THESE DATA HAVE BEEN
INPUT INTO THE NCEP GLOBAL MODEL. A WEAK MID-TROPOSPHERIC RIDGE LIES
ALONG THE NORTHWEST GULF OF MEXICO COAST AND THE GLOBAL MODEL
FORECASTS THIS FEATURE TO PERSIST.  NOT SURPRISINGLY...THE CONSENSUS
OF THE TRACK PREDICTION MODELS IS FOR A TURN TO THE LEFT...TOWARD
THE SOUTH TEXAS COAST.   ONLY SLIGHT CHANGES HAVE BEEN MADE TO THE
PREVIOUS OFFICIAL FORECAST TRACK...AND NO NORTHWARD EXTENSION OF THE
WARNINGS IS DEEMED NECESSARY AT THIS TIME.

THE OFFICIAL FORECAST...BASED ON THE OBJECTIVE GUIDANCE... SHOWS A
SLOWING OF THE FORWARD SPEED.  IF THIS DOES NOT OCCUR THEN THE
CENTER WILL REACH THE COAST SOONER THAN INDICATED.  DO NOT FOCUS ON
THE EXACT TRACK.  EVEN THOUGH BRET IS EXPECTED TO MOVE ONSHORE IN
THE HURRICANE WARNING AREA...IT IS NOT POSSIBLE TO SPECIFY A PRECISE
POINT AND TIME OF LANDFALL.
 
PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/0900Z 26.0N  95.7W   120 KTS
12HR VT     22/1800Z 26.6N  96.1W   120 KTS
24HR VT     23/0600Z 27.3N  96.9W   120 KTS
36HR VT     23/1800Z 27.5N  97.5W   110 KTS...INLAND
48HR VT     24/0600Z 27.5N  98.2W    70 KTS...INLAND
72HR VT     25/0600Z 27.3N  99.0W    30 KTS...INLAND
 
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