HENRI #15 - DISCUSSION

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WTNT42 KNHC 070829
TCDAT2
TROPICAL DEPRESSION HENRI DISCUSSION NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT SUN SEP 07 2003

AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT RECENTLY
INVESTIGATED HENRI...AND REPORTED A MINIMUM PRESSURE OF 1007 MB AND
MAXIMUM 850-MB FLIGHT-LEVEL WINDS OF 37 KT EAST OF THE CENTER.
INFRARED IMAGERY SHOWS THE NEAREST DEEP CONVECTION LOCATED 100 N MI
NORTHEAST OF THE EXPOSED LOW LEVEL CENTER. THE ADVISORY INITIAL
MAXIMUM WIND SPEED IS KEPT AT 30 KT BASED ON THIS DATA.

THE LOW LEVEL CIRCULATION CENTER IS NOT WELL DEFINED BASED ON
AIRCRAFT WINDS. HENRI CONTINUES TO SLOW ITS FORWARD SPEED WITH AN
UNCERTAIN INITIAL MOTION OF 040/7 BASED ON THE PAST 12 HOURS OF
MOTION. ALL OF THE GLOBAL MODELS SHOW HENRI AS A LOW LEVEL
CIRCULATION WITH STRONG SOUTHWESTERLIES ALOFT AND THESE MODELS SHOW
HENRI GETTING TRAPPED TO THE SOUTH OF SHALLOW HIGH PRESSURE SYSTEM
OVER THE NEXT 5 DAYS. THE OFFICIAL FORECAST FOLLOWS THIS REASONING
AND IS ADJUSTED TO THE LEFT OF THE PREVIOUS ADVISORY WITH SLOWER
FORWARD SPEEDS.

THE GLOBAL MODELS SUGGEST SLIGHT STRENGTHENING FROM THE INCREASING
PRESSURE GRADIENT AND THE SHIPS MODEL ALSO SHOWS MODEST
STRENGTHENING...EVEN THOUGH THERE IS NEARLY 25-KNOT VERTICAL SHEAR
OVER HENRI AND INCREASING SHEAR IS FORECAST. THE INTENSITY
FORECAST IS THE SAME AS THE PREVIOUS ADVISORY...AND BRINGS THE WIND
SPEED TO 40 KNOTS AT 24 HOURS.

FORECASTER LAWRENCE

FORECAST POSITIONS AND MAX WINDS

INITIAL 07/0900Z 30.8N 79.1W 30 KT
12HR VT 07/1800Z 31.8N 78.2W 35 KT
24HR VT 08/0600Z 32.8N 77.0W 40 KT
36HR VT 08/1800Z 33.7N 75.5W 40 KT
48HR VT 09/0600Z 34.5N 74.0W 35 KT
72HR VT 10/0600Z 35.5N 72.0W 35 KT
96HR VT 11/0600Z 35.5N 70.5W 30 KT
120HR VT 12/0600Z 35.5N 69.5W 25 KT