Subject: Pacific-EN: Hurricane Jimena Discussion Number 9

From: SIU Weather Processor <[email-masked]>
Date: Wed, 27 Aug 1997 09:45:01 -0500

683
WTPZ42 KNHC 271434
TCDEP2
HURRICANE JIMENA DISCUSSION NUMBER   9
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT WED AUG 27 1997

SATELLITE IMAGERY SHOWS A SMALL EYE EMBEDDED IN VERY COLD CLOUD
TOPS.  SUBJECTIVE DVORAK INTENSITY ESTIMATES USING THE EYE PATTERN
AND OBJECTIVE T-NUMBERS SUGGEST THAT MAXIMUM WINDS ARE LEVELLING OFF
NEAR 115 KNOTS.  THE RAPID STRENGTHENING THAT OCCURRED DURING THE
PAST 24 HOURS IS DIFFICULT TO EXPLAIN.  ON THE LARGER-SCALE...IT MAY
HAVE BEEN RELATED TO SOME KIND OF INTERACTION WITH A MID- TO UPPER-
TROPOSPHERIC TROUGH WHICH PASSED JUST TO THE NORTH OF THE TROPICAL
CYCLONE.  A STRONG UPPER-LEVEL OUTFLOW JET IS OBSERVED STREAMING
NORTHEASTWARD FROM JIMENA...BUT THIS MAY MERELY BE THE RESULT OF THE
EXPLOSIVE INTENSIFICATION.  INTENSITY MAY FLUCTUATE DURING THE NEXT
12 TO 24 HOURS IN RESPONSE TO EYEWALL CYCLES.  A SLOW WEAKENING IS
FORECAST TO BEGIN IN 24 HOURS OR SO SINCE THE HURRICANE WILL BE
MOVING SLIGHTLY COOLER WATERS.

INITIAL MOTION ESTIMATE IS 340/7.  WATER VAPOR IMAGERY SUGGESTS THAT
A RIDGE IS STARTING TO BUILD IN TO THE NORTHWEST AND NORTH OF
JIMENA.  THIS SHOULD CAUSE THE MOTION TO TURN GRADUALLY TO THE WEST-
NORTHWEST.  THE OFFICIAL TRACK FORECAST IS CLOSE TO THE PREVIOUS
FORECAST AND TO THAT SHOWN BY THE MEDIUM-DEPTH BAM GUIDANCE.

PASCH

FORECAST POSITIONS AND MAX WINDS

INITIAL     27/1500Z 13.9N 136.1W   115 KTS
12HR VT     28/0000Z 14.8N 136.5W   115 KTS
24HR VT     28/1200Z 15.9N 137.3W   110 KTS
36HR VT     29/0000Z 16.8N 138.3W   105 KTS
48HR VT     29/1200Z 17.6N 139.6W    95 KTS
72HR VT     30/1200Z 18.5N 142.5W    80 KTS

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