000
WTNT41 KNHC 290238
TCDAT1
 
TROPICAL STORM KIRK DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112012
1100 PM AST TUE AUG 28 2012
 
A LARGE CONVECTIVE BURST...WITH A LARGE AREA OF CLOUD TOP
TEMPERATURES COLDER THAN -70C...HAS PERSISTED NEAR AND TO THE NORTH
OF THE CENTER OF THE TROPICAL CYCLONE FOR THE LAST SEVERAL HOURS.
AN ASCAT PASS FROM 2338 UTC SHOWED RELIABLE WIND VECTORS NEAR 40 KT
OR PERHAPS A LITTLE HIGHER. THEREFORE...THE INITIAL INTENSITY IS
CONSERVATIVELY SET AT 40 KT...AND THE SYSTEM IS UPGRADED TO
TROPICAL STORM KIRK. THE INTENSITY FORECAST IS TRICKY. THE SHIPS
MODEL SHOWS SOUTHWESTERLY SHEAR REMAINING GENERALLY BETWEEN 15 AND
20 KT FOR THE NEXT SEVERAL DAYS. IN ADDITION...GOES-R IMAGERY SHOWS
A SIGNIFICANT AMOUNT OF DRY AIR WEST OF THE CYCLONE. WHILE THESE
CONDITIONS SEEM UNFAVORABLE FOR SIGNIFICANT INTENSIFICATION...THE
SHIPS AND LGEM MODELS SUGGEST THAT KIRK COULD BECOME A HURRICANE IN
A FEW DAYS. THE OFFICIAL FORECAST HAS BEEN ADJUSTED SIGNIFICANTLY
UPWARD BUT IS STILL BELOW THE STATISTICAL-DYNAMICAL GUIDANCE.
 
RECENT MICROWAVE DATA HAS HELPED LOCATE THE CENTER OF KIRK...AND THE
INITIAL MOTION ESTIMATE IS A MORE CONFIDENT 280/10.  A CONTINUED
WESTWARD TO WEST-NORTHWESTWARD MOTION AT ABOUT THE SAME SPEED IS
EXPECTED DURING THE NEXT DAY OR TWO. AFTER THAT TIME...A GRADUAL
TURN TO TOWARD THE NORTH AND THEN NORTHEAST WITH A FASTER FORWARD
SPEED IS FORECAST AS THE SYSTEM REACHES THE WESTERN EDGE OF THE
SUBTROPICAL RIDGE AND BECOMES INFLUENCED BY AN APPROACHING LARGE-
SCALE TROUGH.  THE LATEST GFS RUN HAS A MUCH DEEPER SYSTEM AND...AS
A RESULT...HAS SHIFTED WELL TO THE EAST WITH RECURVATURE OCCURRING
AROUND 50W. THE NEW OFFICIAL NHC FORECAST CONSIDERS THE GFS AN
OUTLIER AT THIS TIME AND REMAINS ON THE WEST SIDE OF THE MODEL
GUIDANCE ENVELOPE...CLOSEST TO THE ECMWF SOLUTION.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0300Z 23.9N  45.0W   40 KT  45 MPH
 12H  29/1200Z 24.2N  46.6W   45 KT  50 MPH
 24H  30/0000Z 24.5N  48.6W   50 KT  60 MPH
 36H  30/1200Z 25.0N  50.9W   55 KT  65 MPH
 48H  31/0000Z 26.0N  52.9W   55 KT  65 MPH
 72H  01/0000Z 29.0N  55.3W   55 KT  65 MPH
 96H  02/0000Z 34.8N  52.9W   55 KT  65 MPH
120H  03/0000Z 42.3N  44.9W   55 KT  65 MPH
 
$$
FORECASTER KIMBERLAIN/CANGIALOSI