Tropical Depression SIXTEEN-E

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TROPICAL DEPRESSION SIXTEEN-E DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT WED OCT 19 2005
 
DEEP CONVECTION HAS PERSISTED IN THE WESTERN SEMICIRCLE OF THE
TD-16E CIRCULATION... UNLIKE THE PREVIOUS TWO DAYS WHERE THE LATE
NIGHT AND EARLY MORNING CONVECTIVE FLAREUPS HAD FIZZLED OUT BY THIS
TIME. THE ITCZ HAS ALSO BECOME MORE CONVECTIVELY ACTIVE...
SUGGESTING THAT THE LARGE-SCALE SUBSIDENCE AND AIRMASS
STABILIZATION OVER THE PREVIOUS FEW DAYS HAS DECREASED. DVORAK
INTENSITY ESTIMATES ARE T1.5/25 KT FROM TAFB AND T1.0/25 KT FROM
SAB USING A BANDING PATTERN. HOWEVER... A SHEAR PATTERN YIELDS A
DATA T-NUMBER OF AT LEAST T2.5/35 KT. A NESDIS/CIRA AMSU INTENSITY
ESTIMATE AT 19/1334Z WAS 1006 MB AND 30 KT. A BLEND OF ALL THESE
INTENSITY ESTIMATES IS 30 KT... WHICH MAY BE A LITTLE CONSERVATIVE.
 
THE INITIAL MOTION ESTIMATE IS STILL 280/9... EVEN THOUGH THERE HAVE
BEEN SOME FLUCTUATIONS IN SPEED AS HIGH AS 13 KT.  A BROAD BUT WEAK
MID-LEVEL RIDGE LOCATED NORTH AND NORTHEAST OF THE DEPRESSION IS
EXPECTED TO STEER THE CYCLONE BASICALLY WESTWARD FOR THE NEXT 72
HOURS. BY DAYS 4 AND 5... A MID- TO UPPER-LEVEL TROUGH IS FORECAST
TO DIG SOUTHEASTWARD FROM THE NORTH PACIFIC AND WEAKEN THE WESTERN
PORTION OF THE RIDGE. THE WEAKENING RIDGE... IN COMBINATION AN
INCREASE IN THE SOUTHERLY UPPER-LEVEL WIND FLOW... MAY HELP TO LIFT
THE CYCLONE SLOWLY NORTHWEST OR NORTHWARD LATE IN THE FORECAST
PERIOD. THE OFFICIAL FORECAST TRACK IS CLOSE TO THE PREVIOUS TRACK
AND IS SIMILAR TO THE CONU CONSENSUS MODEL.

THE DEPRESSION IS CURRENTLY EMBEDDED IN FAIRLY MID-LEVEL ENVIRONMENT
...BUT THE LARGE-SCALE INCREASE IN INSTABILITY MENTIONED PREVIOUSLY
SHOULD ALLOW FOR MORE CONVECTION TO DEVELOP DESPITE THE DRY
MID-LEVEL CONDITIONS. THE VERTICAL SHEAR IS FORECAST TO GRADUALLY
DECREASE TO LESS THAN 10 KT BY 24 HOURS... AND THE MID-LEVEL
ENVIRONMENT IS FORECAST GRADUALLY MOISTEN. THESE IMPROVING
ENVIRONMENTAL CONDITIONS SHOULD ALLOW FOR AT LEAST SOME MODEST
STRENGTHENING TO OCCUR FOR THE FIRST 72 HOURS...AND THEN SLOW
WEAKENING IS EXPECTED AS THE SOUTHERLY SHEAR INCREASES. THE
OFFICIAL FORECAST FOLLOWS THE TREND OF THE SHIPS INTENSITY MODEL...
ONLY SLIGHTLY WEAKER... ESPECIALLY AT DAYS 3-5.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/2100Z 12.4N 115.1W    30 KT
 12HR VT     20/0600Z 12.5N 116.7W    30 KT
 24HR VT     20/1800Z 12.7N 118.4W    35 KT
 36HR VT     21/0600Z 13.1N 119.9W    35 KT
 48HR VT     21/1800Z 13.5N 121.0W    40 KT
 72HR VT     22/1800Z 14.1N 122.2W    40 KT
 96HR VT     23/1800Z 14.5N 123.0W    35 KT
120HR VT     24/1800Z 15.0N 124.0W    35 KT

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