426 
 WTNT45 KNHC 171505
 TCDAT5
 TROPICAL STORM OMAR DISCUSSION NUMBER  17
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152008
 1100 AM EDT FRI OCT 17 2008
  
 OMAR HAS RE-INTENSIFIED SOME THIS MORNING AS SHOWN IN THE STRONGLY
 CURVED BANDED STRUCTURE FROM GEOSTATIONARY SATELLITE IMAGERY. THE
 DVORAK ESTIMATE FROM TAFB SUGGESTED 55 KT AT 12 UTC...THOUGH
 IMPROVED DEEP CONVECTION SINCE WOULD INDICATE A STRONGER CYCLONE AT
 ADVISORY TIME. ADDITIONALLY...A WELL-PLACED QUIKSCAT OVERPASS AT
 0922 UTC SHOWED SEVERAL BELIEVABLE 55-60 KT VECTORS AND TWO
 HURRICANE FORCE WINDS...THOUGH THESE MIGHT HAVE SOME RAIN
 CONTAMINATION BOOSTING THE VALUES. CURRENT INTENSITY IS SET AT 60
 KT...ALTHOUGH OMAR COULD BE A MARGINAL HURRICANE.
  
 OMAR HAS ACCELERATED TO ABOUT 30 KT TOWARD THE NORTHEAST UNDER THE
 INFLUENCE OF A SHORTWAVE TROUGH JUST TO THE NORTHWEST AND A
 DEEP-LAYER RIDGE TO THE EAST. THIS TROUGH ADVECTS ALONG QUICKLY
 TOWARD THE EAST-NORTHEAST AND LEAVES OMAR BEHIND...LIKELY CAUSING
 THE CYCLONE TO SLOW DOWN SIGNIFICANTLY IN THE NEXT DAY OR SO. THE
 EXTRATROPICAL STORM THAT WILL EMERGE OFF OF THE U.S. EAST COAST
 EARLY ON SUNDAY IS THE FEATURE THAT IS EXPECTED TO ABSORB OMAR LATE
 IN THE FORECAST PERIOD. THIS IS THE SOLUTION FAVORED BY ALL OF THE
 GLOBAL AND HURRICANE MODELS...WITH THE EXCEPTION OF NOGAPS WHICH
 MAINTAINS OMAR AS A SEPARATE ENTITY AND LOOPS IT BACK TOWARD THE
 SOUTH AND WEST. THE TRACK FORECAST IS BASED A BLEND OF A CONSENSUS
 OF THESE MODELS...WITH THE EXCEPTION OF NOGAPS...AND THE FASTER
 PREVIOUS ADVISORY.
 
 OMAR HAS A SHORT WINDOW OF OPPORTUNITY TO INTENSIFY BEFORE REACHING
 COOLER WATERS AND UNDER MUCH STRONGER SHEAR IN ABOUT 24 HOURS. 
 CURRENTLY...OMAR IS MOVING IN THE DIRECTION OF...BUT FASTER THAN...
 THE SHEAR VECTOR...WHICH MAY HAVE SOMEWHAT COUNTERACTED THE
 OTHERWISE LARGE NEGATIVE SHEAR INFLUENCE.  ANOTHER LIMITING FACTOR
 IS THAT THE CYCLONE IS NEARLY SURROUNDED BY DRY AIR IN THE MID TO
 LOW TROPOSPHERE.  THE FORECAST CALLS FOR NO SIGNIFICANT CHANGE IN
 WINDS DURING THE NEXT DAY OR SO WITH GRADUAL WEAKENING THEREAFTER
 ...IN BEST AGREEMENT WITH THE LGEM STATISTICAL AND HWRF DYNAMICAL
 MODELS.  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      17/1500Z 28.9N  55.1W    60 KT
  12HR VT     18/0000Z 31.4N  53.2W    60 KT
  24HR VT     18/1200Z 33.4N  51.3W    55 KT
  36HR VT     19/0000Z 35.1N  49.2W    50 KT
  48HR VT     19/1200Z 36.6N  47.0W    45 KT
  72HR VT     20/1200Z 39.0N  42.0W    40 KT...BECOMING EXTRATROPICAL
  96HR VT     21/1200Z 40.5N  36.0W    35 KT...EXTRATROPICAL
 120HR VT     22/1200Z...ABSORBED BY EXTRATROPICAL LOW
  
 $$
 FORECASTER LANDSEA/STEWART