000
WTNT43 KNHC 162045
TCDAT3
HURRICANE KARL DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132010
400 PM CDT THU SEP 16 2010
 
REPORTS FROM A NOAA HURRICANE HUNTER AIRCRAFT INDICATE THAT KARL IS
STRENGTHENING.  A DROPSONDE IN THE EYE REPORTED A CENTRAL PRESSURE
OF 977 MB...AND THERE WERE TWO SURFACE WIND ESTIMATES OF 69 KT FROM
THE SFMR.  IN ADDITION...A DROPSONDE IN THE NORTHWESTERN EYEWALL
SUPPORTS 70 KT SURFACE WINDS...AND THE PLANE REPORTED FLIGHT-LEVEL
WINDS OF 83 KT AT 12000 FT.  THESE DATA SUPPORT RAISING THE INITIAL
INTENSITY TO 70 KT.
 
KARL HAS TURNED TO THE LEFT DURING THE PAST SEVERAL HOURS AND THE
INITIAL MOTION IS NOW 270/10. A LOW/MID-LEVEL RIDGE NORTH OF KARL
SHOULD CONTINUE TO STEER THE HURRICANE ON A GENERALLY WESTWARD TRACK
FOR ABOUT THE NEXT 24 HR TO LANDFALL IN MEXICO...FOLLOWED BY A
WESTWARD TO WEST-SOUTHWESTWARD MOTION AS THE RIDGE STRENGTHENS.
OVERALL...THE ENVELOPE OF TRACK GUIDANCE HAS SHIFTED SOUTHWARD
SINCE THE LAST ADVISORY...WITH ONLY THE ECMWF...CANADIAN...AND UKMET
MODELS SHOWING ANY NORTHWARD COMPONENT TO THE MOTION BEFORE
LANDFALL.  THE NEW FORECAST TRACK IS SHIFTED SOUTH OF THE PREVIOUS
ONE...SHOWING AN ALMOST DUE WEST MOTION UNTIL LANDFALL AND A
SOUTH OF WEST MOTION THEREAFTER.  THE NEW FORECAST TRACK IS TO
THE SOUTH OF THE ECMWF...CANADIAN...AND UKMET MODELS...BUT TO THE
NORTH OF THE OTHER DYNAMICAL MODELS AND THE CONSENSUS GUIDANCE.
 
ENVIRONMENTAL CONDITIONS REMAIN VERY CONDUCIVE FOR STRENGTHENING
ALONG THE FORECAST TRACK WITH WARM SEA SURFACE TEMPERATURES AND
LIGHT VERTICAL WIND SHEAR.  THUS...KARL IS EXPECTED TO STRENGTHEN
STEADILY AND POSSIBLY RAPIDLY.  THE LGEM...SHIPS...GFDL...AND
FLORIDA STATE SUPERENSEMBLE ALL FORECAST KARL TO BECOME A CATEGORY
TWO HURRICANE BEFORE LANDFALL...AND THE INTENSITY FORECAST IS FOR A
85 KT LANDFALL INTENSITY AS A BLEND OF THESE FORECASTS.  IT IS NOT
OUT OF THE QUESTION THAT KARL COULD BECOME A MAJOR HURRICANE BEFORE
LANDFALL.  AFTER LANDFALL...KARL SHOULD WEAKEN QUICKLY AS IT MOVES
INTO THE MOUNTAINS OF MEXICO...AND IT IS EXPECTED TO DISSIPATE BY
96 HR IF NOT SOONER.
 
THE NEW FORECAST TRACK HAS REQUIRED WARNINGS TO BE EXTENDED FARTHER
SOUTH ALONG THE COAST OF MEXICO.  IT SHOULD BE NOTED THAT THE NEW
FORECAST TRACK CALLS FOR LANDFALL IN ABOUT 24 HOURS AS COMPARED TO
36 HOURS FOR THE PREVIOUS FORECAST...WHICH HAS REDUCED THE AMOUNT
OF TIME AVAILABLE TO MAKE PREPARATIONS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/2100Z 19.6N  93.7W    70 KT
 12HR VT     17/0600Z 19.7N  94.9W    75 KT
 24HR VT     17/1800Z 19.7N  96.2W    85 KT
 36HR VT     18/0600Z 19.6N  97.6W    55 KT...INLAND
 48HR VT     18/1800Z 19.5N  99.1W    30 KT...INLAND
 72HR VT     19/1800Z 19.0N 102.0W    25 KT...INLAND
 96HR VT     20/1800Z...DISSIPATED
 
$$
FORECASTER BEVEN