000
WTPZ41 KNHC 151440
TCDEP1
TROPICAL DEPRESSION SIX-E DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP062010
800 AM PDT THU JUL 15 2010
 
INTERMITTENT BURSTS OF DEEP CONVECTION...WITH TOPS OCCASIONALLY TO
80C...CONTINUE TO DEVELOP NEAR THE TIGHT LOW-LEVEL CIRCULATION
CENTER OF THE DEPRESSION AS REVEALED BY A 0841Z AMSR OVERPASS.
SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE A CONSENSUS
T1.5/25 KT. AN UW-CIMSS ADT ESTIMATES HAVE AVERAGED T2.1/31 KT OVER
THE PAST 3 HOURS...WHILE A 0944Z AMSU ANALYSIS FROM CIRA YIELDED A
PRESSURE ESTIMATE OF 1001 MB AND 34 KT. A BLEND OF THESE DATA GIVES
AN AVERAGE INTENSITY OF 30 KT...AND THAT VALUE IS USED FOR THE
ADVISORY INTENSITY.
 
THE INITIAL MOTION ESTIMATE IS 290/05...A LITTLE SLOWER THAN THE
PREVIOUS ADVISORY AND MUCH SLOWER THAN THE MODEL GUIDANCE.
OVERALL...THERE REMAINS NO SIGNIFICANT CHANGE TO THE PREVIOUS TRACK
FORECAST REASONING. A MID-LEVEL RIDGE SITUATED OVER THE SOUTHERN
AND SOUTHWESTERN UNITED STATES IS FORECAST TO GRADUALLY BUILD
WESTWARD INTO THE EASTERN PACIFIC DURING THE PERIOD. THE DEEP
EAST-SOUTHEASTERLY FLOW ON THE SOUTH SIDE OF THE RIDGE SHOULD KEEP
THE DEPRESSION MOVING IN A WEST-NORTHWESTWARD DIRECTION FOR THE
NEXT 2 DAYS...WITH A GRADUAL TURN TOWARD THE WEST EXPECTED AFTER
THAT WHEN THE CYCLONE WEAKENS OVER COOLER WATER AND IS STEERED MORE
BY THE LOW-LEVEL EASTERLIES. THE OFFICIAL FORECAST TRACK IS SIMILAR
TO THE PREVIOUS ADVISORY AND REMAINS NEAR THE SOUTHERN EDGE OF THE
GUIDANCE ENVELOPE...AND IS ALSO A LITTLE SLOWER THAN AND SOUTH OF
THE MODEL CONSENSUS...TVCN.

OCCASIONAL BURSTS OF DEEP CONVECTION SHOULD CONTINUE FOR THE NEXT 24
HOURS OR SO...AND COULD RESULT IN THE DEPRESSION BRIEFLY PRODUCING
TROPICAL-STORM-FORCE WINDS. HOWEVER...STRONG EAST-NORTHEASTERLY
VERTICAL SHEAR IS EXPECTED TO CONTINUE DURING THAT PERIOD...WHICH
SHOULD PREVENT ANY PERSISTENT INNER-CORE CONVECTION FROM
DEVELOPING. BY 36-48 HOURS...THE SHEAR IF EXPECTED TO DROP SHARPLY
FROM THE CURRENT 25-30 KT TO LESS THAN 15 KT...WHICH SHOULD ALLOW
FOR MORE ORGANIZED CONVECTION TO DEVELOP NEAR THE WELL-DEFINED
LOW-LEVEL CENTER. HOWEVER...AFTER 48 HOURS THE CYCLONE IS FORECAST
TO MOVE OVER SSTS COLDER THAN 26C...WHICH SHOULD HALT ANY
INTENSIFICATION. NEITHER THE SHIPS OR LGEM INTENSITY MODELS MAKE
THE SYSTEM A TROPICAL STORM...BUT THE GFDL AND HWRF MODELS DO BRING
THE DEPRESSION UP TO 40-45 KT IN 24-36 HOURS. THE OFFICIAL
INTENSITY FORECAST IS A BLEND OF THESE TWO EXTREMES.
 
REPORTS FROM THE NOAA SHIP KA-IMIMOANA...CALL SIGN NWS0009...LOCATED
TO THE WEST OF THE DEPRESSION...HAVE BEEN HELPFUL IN THE ASSESSMENT
OF THE CENTRAL PRESSURE AND WIND FIELD ASSOCIATED WITH THE CYCLONE.
 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      15/1500Z 15.3N 108.5W    30 KT
 12HR VT     16/0000Z 15.7N 109.6W    30 KT
 24HR VT     16/1200Z 16.4N 111.4W    30 KT
 36HR VT     17/0000Z 17.0N 113.2W    35 KT
 48HR VT     17/1200Z 17.4N 115.3W    35 KT
 72HR VT     18/1200Z 17.7N 119.0W    30 KT...DISSIPATING
 96HR VT     19/1200Z 17.7N 122.5W    25 KT...POST-TROP/REMNT LOW
120HR VT     20/1200Z...DISSIPATED
 
$$
FORECASTER STEWART