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HURRICANE JULIETTE DISCUSSION NUMBER  11
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT SUN SEP 23 2001
 
JULIETTE HAS CONTINUED TO RAPIDLY INTENSIFY DURING THE PAST 6 HOURS 
AND IS NOW A CATEGORY 4 HURRICANE ON THE SAFFIR-SIMPSON HURRICANE 
SCALE.  THE INITIAL INTENSITY IS INCREASED TO 115 KT BASED ON A 
DVORAK SATELLITE INTENSITY ESTIMATE OF 115 KT...T6.0...FROM TAFB... 
A 3-HOUR AVERAGE OBJECTIVE DVORAK INTENSITY ESTIMATE OF 140 
KT...ODT7.0...AND A SMALL PINHOLE EYE. THE INITIAL INTENSITY WAS 
HELD BELOW THE ODT VALUE BASED ON THE LOW-LEVEL WIND FIELD REQUIRING 
SOME ADDITIONAL TIME TO SPIN UP AND CATCH UP WITH THE SATELLITE 
SIGNATURES. UPPER-LEVEL OUTFLOW IS IMPRESSIVE AND IS EXPANDING.
 
THE INITIAL MOTION ESTIMATE IS 275/03...BASED ON AN EXPECTED 
RESUMPTION OF A WESTWARD COURSE.  DURING THE PAST 6 HOURS...JULIETTE 
HAS ACTUALLY MADE SEVERAL SMALL CYCLONIC LOOPS... BUT THE GENERAL 
MOTION HAS BEEN A SLOW DRIFT TO THE WEST.  THIS TYPE OF ERRATIC 
MOTION IS NOT UNUSUAL FOR TROPICAL CYCLONES THAT UNDERGO RAPID 
DEEPENING.  HOWEVER...THE SYNOPTIC FLOW PATTERN FAVORS A RETURN TO A 
WEST-NORTHWESTWARD AND EVENTUALLY A NORTHWESTWARD MOTION IN TIME.  
ALL OF THE NHC MODEL GUIDANCE TAKE JULIETTE NORTHWESTWARD FROM ITS 
CURRENT POSITION...EXCEPT FOR NOGAPS WHICH TAKES THE CYCLONE WEST 
AND THEN WEST-NORTHWESTWARD.  NOGAPS IS THE FARTHEST WEST OF ALL THE 
MODELS.  THE REST OF THE NHC MODEL SUITE TAKE JULIETTE TOWARD BAJA 
CALIFORNIA OR INTO THE GULF OF CALIFORNIA.  THE GFDL AND GFDN MODELS 
CONTINUE THEIR TREND OF A SHARP RIGHT-OF-TRACK BIAS AND HAVE THE 
HURRICANE INLAND NEAR MANZANILLO MEXICO IN 36 TO 48 HOURS...WHICH I 
FEEL IS A LITTLE PREMATURE AT THIS TIME GIVEN THE STRENGTH OF THE 
CURRENTLY RIDGE ACROSS NORTHERN MEXICO. THE OFFICIAL TRACK IS CLOSE 
TO THE PREVIOUS FORECAST AND BETWEEN THE AVN AND UKMET MODELS.

JULIETTE APPEARS TO BE ABOUT 18 HOURS INTO A TYPICAL 30-HOUR RAPID 
INTENSIFICATION TREND.  AS SUCH...ANOTHER 12 HOURS OF RAPID 
INTENSIFICATION IS FORECAST BASED ON THE 140 KT ODT SATELLITE 
SIGNATURE AND A VERY FAVORABLE UPPER-LEVEL OUTFLOW ENVIRONMENT THAT 
IS FORECAST TO CONTINUE FOR AT LEAST THE NEXT 48 HOURS.  IT IS QUITE 
POSSIBLE AND PLAUSIBLE THAT JULIETTE COULD REACH CATEGORY 5 STRENGTH 
DURING THE NEXT 24 HOURS.  THE SHIPS INTENSITY MODEL BRINGS JULIETTE 
UP TO 135 KT IN 12 HOURS AND 140 KT IN 24 HOURS.  THE OFFICIAL 
FORECAST IS CLOSE TO THE SHIPS MODEL...BUT SLIGHTLY LOWER DUE TO 
SOME COLD OCEAN UPWELLING EXPECTED SINCE THE CYCLONE IS ONLY 
FORECAST TO MOVE SLOWLY THROUGH THE NEXT 24 HOURS AND THEN GRADUALLY 
MOVE OVER SLIGHTLY COOLER WATER AFTER THAT.  HOWEVER...IF JULIETTE 
MOVES A LITTLE FASTER AND SOONER THAN FORECAST...THEN IT COULD REACH 
140 KT IN 12 HOURS AND ALSO BE STRONGER THAN THE OFFICIAL FORECAST 
IS INDICATING AT THE LATER TIME PERIODS.
 
UNCERTAINTIES IN THE FORECAST TRACK AND INTENSITY...AND THE FACT 
THAT ONLY A SMALL DEVIATION TO THE RIGHT OF THE TRACK COULD BRING 
STRONGER WINDS TO THE SOUTHWEST COAST OF MEXICO PROMPTED THE 
ISSUANCE OF A TROPICAL STORM WARNING AND HURRICANE WATCH FOR A 
PORTION OF THE SOUTHWEST COAST OF MEXICO. JULIETTE IS A POTENTIALLY 
DANGEROUS HURRICANE FOR THE SOUTHWEST COAST OF MEXICO AND BAJA 
CALIFORNIA FOR THE NEXT FEW DAYS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     24/0300Z 14.9N 103.5W   115 KTS
12HR VT     24/1200Z 15.3N 104.4W   130 KTS
24HR VT     25/0000Z 16.2N 105.3W   135 KTS
36HR VT     25/1200Z 17.3N 106.2W   125 KTS
48HR VT     26/0000Z 18.6N 107.2W   120 KTS
72HR VT     27/0000Z 20.5N 107.5W   115 KTS
 
 
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