000
WTNT43 KNHC 192055
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM EDT TUE JUN 19 2012
 
CONVECTION ASSOCIATED WITH THE LOW PRESSURE AREA LOCATED WELL
SOUTHEAST OF THE CANADIAN MARITIMES HAS ACQUIRED ENOUGH ORGANIZATION
AND COVERAGE FOR THE SYSTEM TO BE CLASSIFIED AS A TROPICAL CYCLONE.
THIS IS SUPPORTED BY RECENT DVORAK CLASSIFICATIONS OF T2.5 FROM
TAFB AND T1.5 FROM SAB.  FSU CYCLONE PHASE SPACE DIAGRAMS ALSO SHOW
THE SYSTEM AS A SYMMETRIC WARM CORE...ALBEIT SHALLOW...SYSTEM.  THE
INITIAL WIND SPEED OF 40 KT IS BASED ON EARLIER SCATTEROMETER DATA
AND A SHIP THAT REPORTED 35-KT WINDS TO THE SOUTHEAST OF THE CENTER
THIS MORNING.
 
THE INITIAL MOTION ESTIMATE IS 090/7.  THE TROPICAL STORM IS
FORECAST TO ACCELERATE EASTWARD IN THE MID-LATITUDE WESTERLY
FLOW DURING THE NEXT DAY OR SO.  AFTER THAT TIME...IT IS FORECAST
TO TURN NORTHEASTWARD...THEN NORTHWARD AROUND A DEVELOPING CUT-OFF
LOW.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS GENERAL
SCENARIO...BUT THERE IS SOME SPREAD AS TO HOW SHARP THE CYCLONE
TURNS NORTHWARD.  FOR NOW...THE OFFICIAL FORECAST LIES NEAR THE
MIDDLE OF THE GUIDANCE ENVELOPE...BETWEEN THE GFS AND ECMWF 
MODELS.
 
LITTLE CHANGE IN STRENGTH IS EXPECTED DURING THE NEXT DAY OR SO AS
CHRIS TRAVERSES THE MARGINALLY WARM WATERS NEAR THE SOUTHERN EDGE
OF THE GULF STREAM.  THE CYCLONE SHOULD MOVE OVER COLDER WATERS IN
36-48 HOURS...ALTHOUGH GLOBAL MODELS SHOW THE LOW STRENGTHENING AS
A BAROCLINIC SYSTEM AT THAT TIME.  THE CYCLONE IS LIKELY TO BE
ABSORBED BY A LARGER EXTRATROPICAL LOW PRESSURE AREA IN 3 TO 4
DAYS...AND THIS IS REFLECTED IN THE NHC FORECAST.

ONLY TWICE BEFORE...IN 1887 AND 1959...HAS THE THIRD STORM OF THE
SEASON FORMED EARLIER THAN THIS DATE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/2100Z 39.3N  57.7W   40 KT  45 MPH
 12H  20/0600Z 39.2N  54.8W   40 KT  45 MPH
 24H  20/1800Z 39.5N  50.5W   40 KT  45 MPH
 36H  21/0600Z 40.9N  46.1W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  21/1800Z 43.3N  44.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  22/1800Z 45.5N  45.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  23/1800Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BROWN