HURRICANE JOYCE DISCUSSION NUMBER 15
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT FRI SEP 29 2000

ALTHOUGH INFRARED IMAGERY DOES NOT SHOW A WELL DEFINED CENTER...A
RECENT SSMI PASS SHOWS A SMALL EYE TYPE FEATURE. BASED ON
THIS...THE INITIAL MOTION ESTIMATE IS 250/10 COMPARED TO 260/10 SIX
HOURS AGO. MOST OF THE GUIDANCE MODELS TURN THE HURRICANE TO THE
WEST-NORTHWEST OR NORTHWEST IN 72 HOURS. IT IS NOT CLEAR WHY THIS
IS SO EXCEPT THAT THE 00Z AVIATION RUN SHOWS A VERY WEAK LITTLE
TROUGH AT 500 MB NOT TOO FAR NORTH OF JOYCE IN 72 HOURS. IN ANY
CASE THE OFFICIAL FORECAST TRACK IS SHIFTED SLIGHTLY SOUTH OF THE
PREVIOUS ADVISORY BASED ON THE INITIAL MOTION UNTIL 72 HOURS WHEN
THE FORECAST IS SLIGHTLY NORTH OF THE PREVIOUS ADVISORY. THE 72
HOUR FORECAST POSITION SLIGHTLY FAVORS THE UKMET WHICH HAS THE
CENTER JUST WEST OF THE WINDWARD ISLANDS IN 72 HOURS. THE GFDL AND
THE FSU EXPERIMENTAL SUGGEST THAT THE TRACK COULD COMPLETELY MISS
THE ISLANDS. IN ANY CASE IT IS TOO EARLY TO TELL ABOUT THIS.

THE ORGANIZATION OF THE DEEP CONVECTION HAS LOOKED PRETTY CRUMMY
OVERNIGHT...BUT THE LAST COUPLE OF IMAGES SHOW A SMALL CDO POSSIBLY
REDEVELOPING NEAR THE CENTER. OTHERWISE I MIGHT HAVE DECREASED THE
CURRENT 75 KNOT WIND SPEED A LITTLE. THE SHIPS GUIDANCE INDICATES A
FAVORABLE ENVIRONMENT AND BRINGS THE WINDS TO 98 KNOTS IN 72 HOURS.
SO THE WIND SPEED FORECAST IS IDENTICAL TO THE PREVIOUS ADVISORY.

There's a high in the mid-Atlantic pushing Joyce towards the south: http://www.goes.noaa.gov/browsh3.html (Isaac is really impressive!)

Computer models, however, predict that Joyce will return to the WNW after 50W, which is bad news for us.
http://www.wunderground.com/tropical/tracking/at200014.html

Let's hope these predictions are wrong and that she will continue this WSW track. If so, South Americans should keep an eye on this one.
Victor