Tropical Storm ARLENE

ZCZC MIATCDAT1 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM ARLENE DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
4 AM CDT SAT JUN 11 2005
 
INFRARED SATELLITE IMAGERY INDICATES THAT CONVECTION ASSOCIATED WITH
ARLENE HAS BECOME RATHER DISORGANIZED...WITH NO NEW SIGNIFICANT
CONVECTIVE BURSTS TO REPLACE THE ONE THAT DISSIPATED JUST AFTER
00Z.  AN AIR FORCE RESERVE HURRICANE HUNTER HAS FOUND MAXIMUM
FLIGHT-LEVEL WINDS OF 69 KT WELL NORTHEAST OF THE CENTER AT 850
MB...ALONG WITH A MINIMUM CENTRAL PRESSURE OF 993 MB.  COMPARISON
OF AIRCRAFT WINDS WITH BUOYS AND C-MAN STATIONS SOUTH OF
APALACHICOLA SUGGESTS THE FLIGHT-LEVEL WINDS ARE NOT BEING MIXED TO
THE SURFACE AT THE NORMAL 70-80 PERCENT VALUES...AT LEAST AT THAT
DISTANCE FROM THE CENTER.  THE MAXIMUM SUSTAINED WINDS WILL REMAIN
60 KT FOR THIS ADVISORY...ALTHOUGH THIS MIGHT BE A BIT GENEROUS.
 
THE INITIAL MOTION IS 320/16.  ARLENE IS BEING STEERED BY DEEP LAYER
RIDGING OVER THE EASTERN UNITED STATES...WITH ALL AVAILABLE
GUIDANCE INDICATING THE STORM SHOULD GRADUALLY RECURVE AROUND THE
WESTERN PERIPHERY OF THE RIDGE OVER THE NEXT TWO DAYS.  ALL
DYNAMICAL MODELS AGREE WITH THIS SCENARIO...AND THE OFFICIAL
FORECAST CALLS FOR ARELENE TO GRADUALLY TURN NORTH-NORTHWESTWARD
BEFORE LANDFALL ON THE NORTHERN GULF COAST IN 12-18 HR.  GRADUAL
RECURVATURE INTO THE WESTERLIES IS EXPECTED AFTER LANDFALL.
 
THERE SEEM TO BE TWO POSSIBILITIES FOR THE INTENSITY BEFORE
LANDFALL.  THE FIRST IS THAT A NEW CONVECTIVE BURST DEVELOPS DURING
THE UPCOMING DIURNAL MAXIMUM...AND ARLENE MAKES ANOTHER ATTEMPT TO
BECOME A HURRICANE.  THE INTENSITY FORECAST WILL FOLLOW THIS
POSSIBILITY.  HOWEVER...THE SECOND POSSIBILITY IS THAT THE ABUNDANT
DRY AIR SEEN IN WATER VAPOR IMAGERY NEAR ARLENE HAS BEEN ENTRAINED
INTO THE STORM AND WILL SUPPRESS CONVECTION DURING THE REMAINING
TIME BEFORE LANDFALL.  IF THAT HAPPENS...ARLENE MAY WELL WEAKEN
BEFORE LANDFALL.  IT WILL LIKELY TAKE ONE MORE FORECAST CYCLE
BEFORE IT BECOMES CLEAR WHICH POSSIBILITY IS OCCURRING.
 
THERE IS A DISTINCT POSSIBILITY THAT ARLENE WILL NOT BECOME A
HURRICANE.  HOWEVER...THE HURRICANE WARNING FOR THE NORTHERN GULF
COAST WILL REMAIN IN EFFECT UNTIL IT BECOMES CLEAR THAT THIS WILL
NOT HAPPEN.
 
FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0900Z 28.4N  87.1W    60 KT
 12HR VT     11/1800Z 30.1N  88.0W    65 KT
 24HR VT     12/0600Z 32.5N  88.5W    45 KT...INLAND
 36HR VT     12/1800Z 35.5N  88.5W    30 KT...INLAND
 48HR VT     13/0600Z 39.5N  86.5W    20 KT...INLAND DISSIPATING
 72HR VT     14/0600Z...DISSIPATED 
 
$$
NNNN