656 
 WTNT43 KNHC 152032
 TCDAT3
 TROPICAL STORM KARL DISCUSSION NUMBER   5
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132010
 400 PM CDT WED SEP 15 2010
 
 KARL IS SLOWLY WEAKENING AS THE CENTER CROSSES THE YUCATAN
 PENINSULA.  SATELLITE IMAGERY AND DATA FROM THE BELIZE CITY RADAR
 INDICATE THE CYCLONE CONTINUES TO PRODUCE STRONG CONVECTION...BUT
 THIS IS CURRENTLY CONFINED TO THE SOUTHWESTERN QUADRANT.  THERE ARE
 NO OBSERVATION AVAILABLE NEAR THE CORE...AND THUS THE INITIAL
 INTENSITY OF 40 KT IS SOMEWHAT UNCERTAIN.
 
 THE INITIAL MOTION IS NOW 285/13.  THE CYCLONE REMAINS ON THE SOUTH
 SIDE OF A LOW/MID-LEVEL RIDGE CENTERED OVER THE NORTHERN GULF
 COAST...AND THIS FEATURE SHOULD STEER THE CYCLONE GENERALLY
 WEST-NORTHWESTWARD OR WESTWARD ACROSS THE SOUTHWESTERN GULF OF
 MEXICO INTO MAINLAND MEXICO.  THERE REMAINS SOME SPREAD IN THE
 GUIDANCE...WITH THE HWRF INDICATING A MORE NORTHWARD MOTION ON THE
 RIGHT SIDE OF THE GUIDANCE ENVELOPE AND THE GFDN A MORE WESTWARD
 MOTION ON THE LEFT.  SEVERAL OF THE OTHER DYNAMICAL MODELS NOW
 FORECAST KARL TO SLOW ITS FORWARD MOTION BEFORE REACHING THE COAST
 OF MAINLAND MEXICO...AND ALSO FORECAST A TURN TO SOUTH OF WEST
 MOTION NEAR OR JUST AFTER LANDFALL.  THE NEW FORECAST TRACK
 REFLECTS BOTH OF THESE POSSIBILITIES...WITH THE NEW TRACK BEING
 SIMILAR TO...BUT A LITTLE SLOWER THAN...THE PREVIOUS TRACK AFTER
 36 HR.
  
 KARL IS FORECAST TO WEAKEN TO A TROPICAL DEPRESSION BY THE TIME IT
 REACHES THE WEST COAST OF THE YUCATAN PENINSULA IN ABOUT 12 HR. 
 ONCE THE CENTER REACHES WATER...THE COMBINATION OF WARM SEA SURFACE
 TEMPERATURES AND LIGHT VERTICAL WIND SHEAR SHOULD ALLOW
 RE-INTENSIFICATION AS FORECAST BY ALL GUIDANCE.  IT SHOULD BE NOTED
 THAT THE HWRF...WHILE FORECASTING STRENGTHENING...HAS CONSISTENTLY
 KEPT KARL AT LESS THAN HURRICANE STRENGTH.  GIVEN THE SEEMINGLY
 FAVORABLE ENVIRONMENT...THE INTENSITY FORECAST CALLS FOR KARL TO
 REACH HURRICANE STRENGTH OVER THE GULF OF MEXICO IN AGREEMENT WITH
 THE SHIPS AND LGEM MODELS.  THE FORECAST SHOWS A PEAK INTENSITY OF
 70 KT...BUT KARL COULD BECOME STRONGER THAN THAT BETWEEN THE 48 AND
 72 HR FORECAST POINTS.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      15/2100Z 19.0N  89.4W    40 KT...INLAND
  12HR VT     16/0600Z 19.6N  90.9W    30 KT...OVER WATER
  24HR VT     16/1800Z 20.5N  92.7W    35 KT
  36HR VT     17/0600Z 21.1N  94.4W    50 KT
  48HR VT     17/1800Z 21.3N  95.7W    65 KT
  72HR VT     18/1800Z 21.5N  98.5W    70 KT...INLAND
  96HR VT     19/1800Z 21.0N 101.5W    25 KT...INLAND
 120HR VT     20/1800Z...DISSIPATED
  
 $$
 FORECASTER BEVEN