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Hurricane OPHELIA (Text)

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TROPICAL STORM OPHELIA DISCUSSION NUMBER  28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT TUE SEP 13 2005
 
SATELLITE IMAGERY AND RADAR DATA INDICATE THAT OPHELIA IS GRADUALLY
BECOMING BETTER ORGANIZED.  THE CONVECTIVE TOPS HAVE COOLED...
ESPECIALLY TO THE SOUTHEAST OF THE CENTER...AND THE CONVECTION IS
STARTING TO WRAP AROUND THE WEST SIDE OF THE CIRCULATION.  THE LAST
AIR FORCE RESERVE HURRICANE HUNTER IN THE STORM REPORTED A CENTRAL
PRESSURE OF 990 MB...WITH MAXIMUM FLIGHT-LEVEL WINDS BETWEEN 60-65
KT AND SURFACE WINDS OF 55 KT FROM DROPSONDES.  THIS WOULD NOT
NORMALLY SUPPORT 60 KT SURFACE WINDS...BUT THE INITIAL INTENSITY
WILL REMAIN 60 KT BASED ON THE IMPROVED ORGANIZATION SINCE THE
AIRCRAFT LEFT.

OPHELIA HAS MOVED LITTLE SINCE 00Z...WITH THE CENTER MEANDERING
AROUND INSIDE THE BROAD CIRCULATION.  WATER VAPOR IMAGERY SHOWS THE
MID/UPPER-LEVEL RIDGE AXIS NORTH OF OPHELIA IS NOW ALONG 81W...
MOVING STEADILY EASTWARD.  ONCE THE RIDGE MOVES EAST OF 78W...WHICH
SHOULD TAKE 12-18 HR...OPEHLIA SHOULD BEGIN A SLOW NORTHWARD MOTION
THROUGH ABOUT 36 HR.  AFTER THAT...INCREASING DEEP-LAYER
SOUTHWESTERLY FLOW SHOULD TURN OPHELIA NORTHEASTWARD WITH SOME
ACCELERATION.  MODEL GUIDANCE HAS COME INTO MUCH BETTER AGREEMENT
ON THIS SCENARIO...WITH THE GFDL AND THE GLOBAL MODELS FORECASTING
OPHELIA TO BE NEAR CAPE FEAR IN 30-36 HR...FOLLOWED BY PASSAGE
ACROSS EXTREME EASTERN NORTH CAROLINA INTO THE ATLANTIC.  THE NEW
FORECAST TRACK IS AN UPDATE OF THE PREVIOUS PACKAGE THROUGH 48
HR...ALONG THE LEFT SIDE OF THE MAIN ENVELOPE OF GUIDANCE.  IT IS
ALSO FASTER THAN THE PREVIOUS FORECAST...ALTHOUGH NOT AS FAST AS
MOST OF THE GLOBAL MODELS.  IT SHOULD BE NOTED THAT SOME WESTERLY
COMPONENT OF MOTION IS STILL POSSIBLE IN THE NEXT 12-18 HR BEFORE
THE NORTHWARD TURN OCCURS.

THE INTENSITY FORECAST REMAINS SOMEWHAT PROBLEMATIC.  WHILE THE CORE
OF OPHELIA IS OVER THE GULF STREAM WITH SEA SURFACE TEMPERATURES OF
NEAR 28C...MUCH OF THE WATER ON EITHER SIDE OF THE GULF STREAM IS
27C OR COLDER.  WATER VAPOR IMAGERY CONTINUES TO INDICATE
MID/UPPER-LEVEL DRY AIR SURROUNDING THE STORM...AND SURFACE DATA
SHOWS COOLER AND DRIER AIR TRYING TO ENTRAIN INTO THE SOUTHWEST
SIDE.  COMBINE THESE FACTORS WITH THE LARGE RADIUS OF MAXIMUM WINDS
AND IT SUGGESTS THAT OPHELIA SHOULD NOT STRENGTHEN VERY QUICKLY
EVEN THOUGH THE UPPER-LEVEL WINDS ARE GENERALLY FAVORABLE.  NONE OF
THE INTENSITY GUIDANCE CALLS FOR MORE THAN 67 KT WINDS...SO THE
INTENSITY FORECAST WILL ONLY STRENGTHEN OPHELIA BACK TO 65 KT. 
THAT BEING SAID...IF THE STORM CONTINUES TO GENERATE CONVECTION AS
STRONG AS CURRENTLY OCCURRING THERE IS A CHANCE IT COULD GET A
LITTLE STRONGER.  AFTER CROSSING NORTH CAROLINA...OPHELIA SHOULD
WEAKEN AS IT MOVES INTO THE WESTERLIES AND BECOME EXTRATROPCIAL BY
120 HR.

FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/0900Z 32.0N  78.0W    60 KT
 12HR VT     13/1800Z 32.4N  78.2W    65 KT
 24HR VT     14/0600Z 33.1N  78.2W    65 KT
 36HR VT     14/1800Z 34.0N  77.8W    65 KT
 48HR VT     15/0600Z 34.9N  76.9W    65 KT...INLAND
 72HR VT     16/0600Z 36.5N  74.0W    55 KT...OVER WATER
 96HR VT     17/0600Z 39.0N  69.0W    50 KT
120HR VT     18/0600Z 44.0N  60.0W    40 KT...EXTRATROPICAL
 
 
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