Subject: Pacific-EN: Tropical Storm Ignacio Discussion Number 2

From: SIU Weather Processor <[email-masked]>
Date: Sun, 17 Aug 1997 15:28:56 +1900

578
WTPZ41 KNHC 172029
TCDEP1
TROPICAL STORM IGNACIO DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT SUN AUG 17 1997

DVORAK CLASSIFICATIONS FROM THE TROPICAL PREDICTION CENTER INDICATE
THAT THE CYCLONE IS OF MARGINAL STORM STRENGTH...SO IT IS BEING
NAMED.  NO ADDITIONAL INTENSIFICATION IS FORECAST DUE TO THE
PRESENCE OF COOLER WATERS IMMEDIATELY AHEAD OF THE SYSTEM.
WEAKENING SHOULD COMMENCE IN 12 HOURS...OR SOONER...AND THE SYSTEM
SHOULD BE DISSIPATING LATER IN THE FORECAST PERIOD.

VISIBLE FIXES SHOW THAT IGNACIO IS TRACKING A LITTLE TO THE LEFT OF
THE PREVIOUSLY ESTIMATED MOTION.  CURRENT MOTION ESTIMATE IS 310/11.
LATEST WATER VAPOR IMAGERY SHOWS A MID- TO UPPER-LEVEL CYCLONE JUST
NORTH OF 30N120W...WITH A TROUGH TRAILING SOUTHWESTWARD FROM IT.
THIS SYSTEM COULD CAUSE RECURVATURE OF A DEEPER/STRONGER STORM...BUT
IGNACIO IS MORE LIKELY TO BE STEERED BY THE WINDS IN THE LOWER
PORTION OF THE TROPOSPHERE.  THUS THE CURRENT FORECAST RESEMBLES THE
SHALLOW LAYER BAM.  THE GFDL MODEL DISSIPATES IGNACIO IN 12 HOURS.
THIS IS LIKELY A RESULT OF THAT MODELS HIGH SENSITIVITY TO COLDER
WATER.

PASCH

FORECAST POSITIONS AND MAX WINDS

INITIAL     17/2100Z 21.8N 120.5W    35 KTS
12HR VT     18/0600Z 22.9N 121.9W    35 KTS
24HR VT     18/1800Z 24.6N 123.1W    30 KTS
36HR VT     19/0600Z 26.5N 124.0W    30 KTS
48HR VT     19/1800Z 28.5N 124.0W    25 KTS...DISSIPATING
72HR VT     20/1800Z 33.0N 124.0W    20 KTS...DISSIPATING

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
To unsubscribe from WX-TROPL send e-mail to [email-masked] with
"unsub wx-tropl" in the body of your message.  For help with the
WX-TROPL or WX-TALK discussion groups write to [email-masked] or see
http://www.inlink.com/~landmb/intro.html.  For more information on
tropical weather products, see the NCEP Products Homepage at
http://www.nhc.noaa.gov/nhcprod.html.