Tropical Storm CALVIN

ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM CALVIN DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT TUE JUN 28 2005
 
CALVIN REMAINS AN UGLY TROPICAL STORM THIS MORNING...WITH ONLY A
MODEST INCREASE IN THE DEEP CONVECTION IN THE WESTERN SEMICIRCLE
NOTED OVERNIGHT. SATELLITE CURRENT INTENSITY ESTIMATES RANGE FROM
35 TO 45 KT...AND A COUPLE OF SHIPS ABOUT 100 NMI NORTHEAST OF THE
CENTER REPORTED 20-25 KT WINDS AT 06Z. THEREFORE...THE INTENSITY
WILL BE HELD AT 35 KT FOR THIS ADVISORY...BUT IT COULD BE WEAKER.
 
THE INITIAL MOTION ESTIMATE IS 285/09. CALVIN REMAINS ON TRACK...SO
LITTLE CHANGE WAS MADE TO THE PREVIOUS FORECAST OTHER THAN TO SHIFT
IT SLIGHTLY SOUTHWARD...OR TO THE LEFT. WATER VAPOR IMAGERY AND
28/00Z UPPER-AIR DATA INDICATE THE WEAKNESS IN THE MEXICAN
SUBTROPICAL RIDGE OVER SOUTHWESTERN MEXICO HAS FILLED IN AND
DEEP-LAYER EASTERLY FLOW IS BEGINNING TO AFFECT CALVIN. THE
OFFICIAL FORECAST TRACK REMAINS NORTH OF THE NHC MODEL CONSENSUS
AND IS CLOSE TO THE MEDIUM BAM AND GFDL SOLUTIONS.

WATER VAPOR AND INFRARED SATELLITE IMAGERY INDICATE THAT THE
UPPER-LEVEL SHEAR HAS ABATED SLIGHTLY...WHICH HAS ALLOWED SOME
CONVECTIVE BANDING TO REDEVELOP. HOWEVER...ANOTHER SURGE OF STRONG
UPPER-LEVEL EASTERLIES WAS NOTED UPSTREAM EAST OF ACAPULCO THAT
SHOULD AFFECT CALVIN WITHIN THE NEXT 12-18 HOURS. THERE WILL LIKELY
BE BRIEF PERIODS OF DEEP CONVECTIVE BURSTS DURING THE NEXT 24 HOURS
OR SO BEFORE CALVIN REACHES COOLER WATER...AND DRIER AND MORE
STABLE AIR. AS SUCH...ONLY SLIGHT STRENGTHENING IS INDICATED IN 12
HOURS...BUT THERE COULD EASILY BE 5 KT INTENSITY FLUCTUATIONS AT
ANY TIME BEFORE STEADY WEAKENING BEGINS IN ABOUT 36 HOURS.

THE TROPICAL STORM WATCH WILL LIKELY BE DISCONTINUED LATER TODAY
SINCE CALVIN IS EXPECTED TO CONTINUE TO MOVE SLOWLY AWAY FROM
MEXICO.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0900Z 15.9N 102.3W    35 KT
 12HR VT     28/1800Z 16.2N 103.8W    40 KT
 24HR VT     29/0600Z 16.6N 105.8W    35 KT
 36HR VT     29/1800Z 16.8N 107.8W    30 KT
 48HR VT     30/0600Z 17.0N 109.5W    25 KT...DISSIPATING
 72HR VT     01/0600Z 17.0N 112.0W    20 KT...REMNANT LOW
 96HR VT     02/0600Z 17.0N 114.5W    20 KT...REMNANT LOW
120HR VT     03/0600Z 17.0N 117.0W    20 KT...REMNANT LOW
 
 
$$
NNNN