000
WTPZ41 KNHC 302036
TCDEP1
TROPICAL DEPRESSION ALVIN DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP012007
200 PM PDT WED MAY 30 2007
 
SATELLITE IMAGES INDICATE THAT THE CIRCULATION OF ALVIN HAS BECOME
DISTORTED. THE MAIN CENTER...AS INDICATED BY MICROWAVE DATA...SEEMS
TO BE ON THE EASTERN EDGE OF THE THUNDERSTORM ACTIVITY.
HOWEVER...THERE IS SOME EVIDENCE OF A WEAK LOW-LEVEL SWIRL ON THE
WESTERN SIDE OF WEAKENING DEEP CONVECTION. DESPITE THE GRADED
SATELLITE PRESENTATION...A 1313 UTC QUIKSCAT PASS SUGGESTED WINDS
OF ABOUT 30 KT. ALTHOUGH DVORAK INTENSITY ESTIMATES ARE FALLING...
THE INITIAL INTENSITY WILL BE KEPT AT 30 KT...PERHAPS GENEROUSLY.
THE INTENSITY FORECAST IS BASICALLY A BLEND OF PERSISTENCE AND THE
SHIPS/GFDL MODELS. IT IS A BIT OF A MYSTERY WHY THIS SYSTEM HAS
FAILED TO INTENSIFY...AND SINCE THE ENVIRONMENT IS ONLY GETTING
LESS FAVORABLE WITH TIME...THERE IS NO GOOD REASON TO FORECAST
ANYTHING BUT SLOW WEAKENING.
 
THE BEST ESTIMATE OF INITIAL MOTION IS 290/3.  A STOUT RIDGE TO THE
NORTH OF ALVIN SHOULD FORCE A WESTWARD TURN SOON... FOLLOWED BY A
TURN MORE TOWARD THE WEST-SOUTHWEST IN A DAY OR TWO.  THERE IS
RELATIVELY GOOD AGREEMENT ON THIS PATH...THOUGH THE UKMET KEEPS
THE SYSTEM VIRTUALLY STATIONARY AS ALVIN GETS CAUGHT UP IN THE
LARGER ITCZ CIRCULATION TO THE EAST.  THE OFFICIAL FORECAST IS
BASICALLY AN UPDATE OF THE PREVIOUS FORECAST...NUDGED SOUTHWARD.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/2100Z 13.4N 115.0W    30 KT
 12HR VT     31/0600Z 13.5N 115.5W    25 KT
 24HR VT     31/1800Z 13.5N 116.4W    25 KT
 36HR VT     01/0600Z 13.4N 117.3W    25 KT
 48HR VT     01/1800Z 13.1N 118.2W    25 KT
 72HR VT     02/1800Z 12.5N 119.5W    20 KT...REMNANT LOW
 96HR VT     03/1800Z 11.7N 120.7W    20 KT...REMNANT LOW
120HR VT     04/1800Z 10.5N 122.5W    20 KT...REMNANT LOW
 
$$
FORECASTER BLAKE