[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 060255
TCDAT2

TROPICAL DEPRESSION KAREN DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122013
1000 PM CDT SAT OCT 05 2013

KAREN HAS ESSENTIALLY REMAINED STATIONARY FOR THE LAST SEVERAL HOURS
AND THAT LACK OF MOTION...COUPLED WITH INCREASING UPPER-LEVEL WINDS
AHEAD OF AN EASTWARD-MOVING DEEP-LAYER TROUGH...HAS INCREASED THE
SHEAR SIGNIFICANTLY ACROSS THE CYCLONE. THE RESULT IS THAT
CONVECTION HAS WEAKENED AND BECOME DISPLACED WELL TO THE EAST AND
SOUTHEAST OF THE LOW-LEVEL CIRCULATION CENTER. SATELLITE
CLASSIFICATIONS FROM TAFB SUPPORTED KEEPING KAREN AS A BORDERLINE
TROPICAL STORM AT 00Z...BUT THE LACK OF CONVECTION NEAR THE CENTER
SINCE THEN REQUIRES A DOWNGRADE TO DEPRESSION STATUS AT THE 03Z
ADVISORY TIME. GIVEN THAT THE VERTICAL WIND SHEAR IS FORECAST TO
GET EVEN STRONGER OVER THE NEXT 2 DAYS...RE-STRENGTHENING BACK TO
TROPICAL STORM STATUS IS NOT LIKELY...ESPECIALLY SINCE THE
MID-LEVELS OF THE TROPOSPHERE WILL BECOME INCREASINGLY DRIER AS
WELL...PREVENTING THE RE-DEVELOPMENT OF DEEP CONVECTION OVER THE
CENTER. AS A RESULT...TROPICAL STORM WARNINGS HAVE BEEN
DISCONTINUED.

THE STATIONARY MOTION OF KAREN THE PAST 6-9 HOURS HAS BEEN DUE TO A
NORTHWEST-TO-SOUTHEAST ORIENTED MID-/UPPER-LEVEL RIDGE LOCATED
ACROSS FLORIDA AND THE SOUTHEASTERN UNITED STATES...WHICH HAS
BLOCKED ANY EASTWARD MOTION BY THE CYCLONE. THIS BLOCKING PATTERN
IS EXPECTED TO SHIFT SLOWLY EASTWARD OVER THE NEXT TWO DAYS...
ALLOWING KAREN OR ITS REMNANTS TO MOVE IN A EASTWARD TO
EAST-NORTHEASTWARD DIRECTION UNTIL THE CYCLONE DISSIPATES IN 48-72
HOURS OR IS ABSORBED BY AN APPROACHING FRONTAL SYSTEM. THE NHC
FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND THE
CONSENSUS MODEL TVCA...AND SHOWS KAREN PASSING NEAR OR OVER THE
EXTREME SOUTHEASTERN TIP OF LOUISIANA IN ABOUT 24 HOURS...AND
REMAINING JUST OFFSHORE OF THE NORTHERN GULF COAST AFTER THAT.

FORECAST POSITIONS AND MAX WINDS

INIT  06/0300Z 28.1N  91.9W   30 KT  35 MPH
 12H  06/1200Z 28.7N  90.7W   30 KT  35 MPH
 24H  07/0000Z 29.1N  88.4W   30 KT  35 MPH
 36H  07/1200Z 29.3N  86.1W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  08/0000Z 29.5N  83.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  09/0000Z...DISSIPATED

$$
FORECASTER STEWART



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