Tropical Storm DANNY

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TROPICAL STORM DANNY DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 PM EDT THU AUG 27 2009
 
DANNY REMAINS VERY DISORGANIZED IN ITS SATELLITE PRESENTATION.
LITTLE DEEP CONVECTION HAS BEEN NOTED NEAR THE ESTIMATED CENTER.
THERE ARE A FEW CLUSTERS OF DEEP CONVECTION OVER THE EASTERN AND
NORTHERN PORTIONS OF THE CIRCULATION...BUT THIS CONVECTION SHOWS
LITTLE OR NO EVIDENCE OF BANDING FEATURES.  DROPSONDE DATA FROM THE
NOAA G-IV JET AIRCRAFT SUGGEST THAT THE CYCLONIC CIRCULATION OF
DANNY HAS LITTLE VERTICAL DEPTH.  A NOAA P-3 HURRICANE HUNTER
AIRCRAFT...CONDUCTING A RESEARCH MISSION IN DANNY THIS EVENING...
INDICATES THAT THE STRONGEST WINDS CONTINUE TO BE DISPLACED WELL TO
THE NORTHEAST OF THE CENTER.  PEAK WINDS REPORTED BY THE PLANE WERE
42 KT...SO THE INITIAL INTENSITY IS REDUCED TO 40 KT FOR THIS
ADVISORY.  DANNY HAS BEEN EXPERIENCING STRONG WEST-SOUTHWESTERLY
SHEAR DUE TO AN UPPER-LEVEL TROUGH AND CYCLONIC SHEAR AXIS TO ITS
WEST.  THERE IS STILL A WINDOW OF OPPORTUNITY FOR THE STORM TO
STRENGTHEN AS GLOBAL MODELS SHOW THE UPPER-LEVEL FLOW BECOMING MORE
ANTICYCLONIC...WITH SOME LESSENING OF THE SHEAR DURING THE NEXT 24
HOURS.  THEREFORE THE OFFICIAL FORECAST SHOWS SOME STRENGTHENING
OVER THE NEXT DAY OR SO.  HOWEVER BY 48 HOURS THE SHEAR OVER DANNY
IS EXPECTED TO BE 40 KT OR MORE SO ANY INTENSIFICATION OF THE
SYSTEM AS A TROPICAL CYCLONE SHOULD CEASE BY THAT TIME.  IN
FACT...BY 48 HOURS...THE GLOBAL MODELS AND THE FSU CYCLONE PHASE
SPACE ANALYSES IMPLY THAT DANNY MAY HAVE ALREADY BECOME AN
EXTRATROPICAL CYCLONE.
 
THE CENTER MEANDERED ABOUT DURING THE DAY...BUT LAST-LIGHT VISIBLE
IMAGERY AND DATA FROM THE AIRCRAFT INDICATED THAT A NORTH TO
NORTH-NORTHWESTWARD MOTION BEGAN SEVERAL HOURS AGO.  HOWEVER...THE
CENTER IS NEARLY IMPOSSIBLE TO DISCERN ON RECENT INFRARED IMAGES.
THE INITIAL MOTION IS AN UNCERTAIN 330/7.  THE TRACK FORECAST
REASONING IS BASICALLY UNCHANGED.  DANNY SHOULD MOVE ON A GENERALLY
NORTHWARD COURSE DURING THE NEXT DAY OR SO ON THE EAST SIDE OF A
SHORT WAVE TROUGH OVER THE SOUTHEASTERN UNITED STATES.  THEREAFTER
A DEEPENING LONG WAVE TROUGH OVER THE EASTERN U.S. SHOULD CARRY
DANNY OR ITS POST-TROPICAL COUNTERPART NORTH-NORTHEASTWARD TO
NORTHEASTWARD AT AN INCREASED FORWARD SPEED.  LATE IN THE FORECAST
PERIOD...THE CYCLONE SHOULD TURN EASTWARD AS IT BECOMES WELL
EMBEDDED IN THE MID-LATITUDE WESTERLIES.  THE OFFICIAL FORECAST IS
VERY SIMILAR TO THE PREVIOUS ONE AND IS CLOSE TO THE MODEL
CONSENSUS.
 
SINCE THE FORECAST TRACK CONTINUES TO KEEP THE AREA OF TROPICAL
STORM FORCE WINDS OFFSHORE...NO ADDITIONAL WATCHES OR WARNINGS ARE
BEING ISSUED FOR THE U.S. EAST COAST AT THIS TIME.  HOWEVER NEW
WATCHES AND/OR WARNINGS COULD BE REQUIRED ON FRIDAY...PARTICULARLY
IF THE FORECAST TRACK SHIFTS TO THE WEST.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0300Z 28.4N  73.5W    40 KT
 12HR VT     28/1200Z 29.7N  74.5W    45 KT
 24HR VT     29/0000Z 32.5N  74.5W    50 KT
 36HR VT     29/1200Z 36.5N  73.0W    55 KT
 48HR VT     30/0000Z 40.5N  69.5W    55 KT
 72HR VT     31/0000Z 47.5N  59.0W    50 KT...EXTRATROPICAL
 96HR VT     01/0000Z 50.5N  46.0W    40 KT...EXTRATROPICAL
120HR VT     02/0000Z 51.0N  31.5W    35 KT...EXTRATROPICAL
 
$$
FORECASTER PASCH/BERG
 
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