courtesy
of National
Hurricane Center
TROPICAL
CYCLONE DISCUSSIONS
Tropical
cyclone discussions are intended for other forecasters
to explain the rationale for the current forecast
level of confidence. However, this information
is also useful to decision makers. The discussions
generally include
- Reasoning
behind the forecast
-
Techniques and guidance used
- Table
of the 12-, 24-, 35-, 48-, 72-, 96-, and 120-hour
positions and maximum wind speed
- Plans
for watches and/or warnings
- Other
meteorological decisions
- The
forecaster's name
WTNT45 KNHC 230300
TCDAT5
HURRICANE ISIDORE DISCUSSION NUMBER 28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SUN SEP 22 2002
THE CENTER HAS MOVED SOUTH OF THE SHORT-TERM FORECAST TRACK...AND
MOVED INLAND OVER NORTHWESTERN YUCATAN A FEW HOURS AGO. THUS THE
CYCLONE IS WEAKENING...AND WILL CONTINUE TO DO SO UNTIL IT MOVES
BACK OVER WATER. ASIDE FROM THE INTERACTION WITH LAND...ATMOSPHERIC
AND OCEANIC CONDITIONS REMAIN QUITE FAVORABLE FOR INTENSIFICATION SO
THE OFFICIAL FORECAST CALLS FOR ISIDORE TO RECOVER ITS PREVIOUS
INTENSITY AND MORE...PRESUMING THAT IT RE-ENTERS THE GULF TOMORROW.
THE OFFICIAL WIND SPEED FORECASTS BY DAYS 2 AND 3 ARE BACK TO THOSE
SHOWN IN THE PREVIOUS ADVISORY. HOWEVER...TROPICAL CYCLONE
INTENSITY FORECASTING HAS A LOT OF UNCERTAINTIES. IF THE INNER CORE
STRUCTURE IS SEVERELY DISRUPTED BY THE CYCLONES TRANSIT OVER
LAND...IT MAY NOT BE ABLE TO RE-INTENSIFY AS MUCH AS ANTICIPATED.
THE FORWARD SPEED APPEARS TO HAVE SLOWED AND CURRENT MOTION IS
ESTIMATED TO BE A SOUTHWESTWARD DRIFT...220/4. THE MORE SOUTHERLY
MOTION WAS PROBABLY THE RESULT OF MID-LEVEL RIDGING TO THE
WEST-NORTHWEST OF ISIDORE. GLOBAL MODELS AND THE GFDL HURRICANE
MODEL AGREE THAT THE SYSTEM WILL TURN BACK TO THE WEST AND NORTHWEST
WITHIN 12 TO 24 HOURS. AFTERWARDS...A MID-TROPOSPHERIC RIDGE SHOULD
BEGIN TO BUILD TO THE EAST OF ISIDORE...WHICH SHOULD INDUCE A MORE
NORTHWARD MOTION. NOT MUCH INCREASE IN FORWARD SPEED IS EXPECTED
UNTIL A MID-LATITUDE TROUGH BEGINS TO AFFECT THE SYSTEM...PROBABLY
BEYOND THIS FORECAST PERIOD.
THE THREE-DAY FORECAST POINT IMPLIES AN EVENTUAL THREAT TO EITHER
THE NORTHWEST OR NORTHERN GULF OF MEXICO COAST...HOWEVER IT IS STILL
TOO EARLY TO BE MORE SPECIFIC ABOUT THE THREAT.
FORECASTER PASCH
FORECAST POSITIONS AND MAX WINDS
INITIAL 23/0300Z 20.8N 89.5W 90 KT
12HR VT 23/1200Z 20.7N 90.3W 80 KT
24HR VT 24/0000Z 21.0N 91.0W 95 KT
36HR VT 24/1200Z 21.8N 92.0W 115 KT
48HR VT 25/0000Z 22.8N 92.5W 125 KT
72HR VT 26/0000Z 25.0N 93.0W 125 KT
96HR VT 27/0000Z 27.0N 92.5W 100 KT
120HR VT 28/0000Z 29.0N 92.0W 90 KT
$$
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