Tropical Storm KARL

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TROPICAL STORM KARL DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132010
1000 PM CDT TUE SEP 14 2010
 
THE AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING KARL
EARLIER THIS EVENING FOUND PEAK 925 MB FLIGHT-LEVEL WINDS OF 49 KT
AND SEVERAL BELIEVABLE 34-39 KT SFMR SURFACE WINDS JUST NORTH OF
THE CENTER AS IT EXITED THE STORM.  THESE DATA WERE THE BASIS FOR
THE INCREASE IN INTENSITY IN THE 0000 UTC INTERMEDIATE ADVISORY.
THE ORGANIZATION OF THE CYCLONE HAS CHANGED LITTLE SINCE THAT
TIME...THEREFORE THE INITIAL INTENSITY REMAINS 40 KT.  THE NEXT AIR
FORCE RESERVE RECONNAISSANCE MISSION IS SCHEDULED TO REACH KARL
AROUND 0600 UTC.

THE AIRCRAFT FIXES AND A COUPLE OF RECENT SSMIS MICROWAVE IMAGES
SHOW THAT THE CENTER IS LOCATED NEAR THE EASTERN EDGE OF THE SMALL
MASS OF DEEP CONVECTION...WHICH SUGGESTS THAT THERE IS SOME LIGHT
EASTERLY SHEAR.  THE SHEAR...HOWEVER...IS NOT EXPECTED TO BE
INHIBITIVE FOR STRENGTHENING...AND SOME INTENSIFICATION IS POSSIBLE
BEFORE KARL REACHES THE EAST COAST OF THE YUCATAN PENINSULA.  OVER
THE SOUTHWESTERN GULF OF MEXICO...WATERS ARE WARM AND THE SHEAR IS
EXPECTED TO BE LIGHT...THEREFORE STRENGTHENING IS EXPECTED.  THE
GFDL...LGEM...SHIPS...AND FLORIDA STATE SUPERENSEMBLE ALL SHOW KARL
AT HURRICANE STRENGTH BEFORE IT REACHES THE COAST OF MAINLAND
MEXICO IN ABOUT 72 HOURS.  THERE IS STILL SOME UNCERTAINTY ABOUT
WHAT KIND OF STRUCTURE KARL WILL HAVE AFTER CROSSING THE YUCATAN
PENINSULA...HOWEVER GIVEN THE FAVORABLE CONDITIONS AND MODEL
AGREEMENT...THE OFFICIAL FORECAST BRINGS KARL TO HURRICANE STATUS
AT THAT TIME.

THE INITIAL MOTION IS 290/13.  THE TRACK FORECAST PHILOSOPHY REMAINS
UNCHANGED.  KARL IS EXPECTED TO MOVE GENERALLY WEST-NORTHWESTWARD
AROUND THE SOUTHERN PORTION OF A DEEP-LAYER RIDGE ALONG THE
NORTHERN GULF COAST.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT
THROUGH 48 HOURS...WITH INCREASED SPREAD THEREAFTER...AS SOME OF THE
MODELS TURN KARL WEST-SOUTHWESTWARD NEAR THE COAST OF MAINLAND
MEXICO.  THE NEW NHC TRACK IS ESSENTIALLY AN UPDATE OF THE PREVIOUS
ADVISORY AND IS IN GOOD AGREEMENT WITH THE GFS AND ECMWF MODELS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      15/0300Z 18.6N  85.5W    40 KT
 12HR VT     15/1200Z 19.2N  87.3W    50 KT
 24HR VT     16/0000Z 20.0N  89.5W    30 KT...INLAND
 36HR VT     16/1200Z 20.7N  91.6W    35 KT
 48HR VT     17/0000Z 21.1N  93.4W    50 KT
 72HR VT     18/0000Z 21.5N  96.7W    65 KT
 96HR VT     19/0000Z 21.5N 100.5W    25 KT...INLAND
120HR VT     20/0000Z...DISSIPATED
 
$$
FORECASTER BROWN
 
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