WTPA42 PHFO 100945 CCA
TCDCP2

TROPICAL STORM FELICIA DISCUSSION NUMBER  27
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP082009
1100 PM HST SUN AUG 09 2009

FELICIA CONTINUES TO CHURN WESTWARD WITH PERSISTENT DEEP CONVECTION 
DISPLACED TO THE NORTHEAST OF ITS EXPOSED LOW LEVEL CIRCULATION 
CENTER. THE MOST RECENT UW/CIMSS ESTIMATE OF VERTICAL WIND SHEAR 
INDICATES WESTERLY SHEAR OF AROUND 27 KT. THE LATEST U.S. AIR FORCE 
RECONNAISSANCE AIRCRAFT FLIGHT DATA CONTINUED TO INDICATE TROPICAL 
STORM FORCE WINDS IN THE NORTHERN SEMICIRCLE OF THE SYSTEM...WITH 
CENTRAL PRESSURE OF 1005 MB AT 0728 UTC. A MAXIMUM 30 SECOND MEAN 
FLIGHT-LEVEL WIND OF 55 KT AT 850 MB WAS OBSERVED. ALSO..A DROPSONDE 
RELEASED IN THE NORTHEAST QUADRANT AROUND 0605 UTC IN THE VICINITY 
OF THE DEEP CONVECTION...MEASURED A MEAN BOUNDARY LAYER WIND OF 54 
KT. BASED ON THESE AIRCRAFT MEASUREMENTS AND DVORAK CI NUMBERS FROM 
PHFO...JTWC AND SAB RANGING FROM 2.0 TO 3.0...45 KT...THE INITIAL 
INTENSITY WILL BE HELD AT 45 KT FOR THIS FORECAST PACKAGE.
 
THE CURRENT MOTION OF FELICIA FOR THIS ADVISORY IS 270 DEG AT 9 
KT...WHICH IS A MORE WESTWARD AND SLIGHTLY SLOWER TRANSLATION THAN 
EARLIER THIS AFTERNOON. THE AIRCRAFT FIXES AND LOOPS OF SATELLITE 
IMAGERY SUPPORT THE MORE WESTWARD MOTION. SINCE THE TROPICAL STORM 
IS A SHEARED SYSTEM...ITS MOTION SHOULD PRIMARILY BE UNDER THE 
INFLUENCE OF THE LOWER LEVEL EASTERLY FLOW SOUTH OF THE SUBTROPICAL 
RIDGE TO THE NORTH. HOWEVER...THE PERSISTENCE OF THE DEEP CONVECTION 
MAY ALSO BE AFFECTING ITS SHORT TERM MOTION.  

THE INDIVIDUAL DYNAMICAL MODELS AND THE CONSENSUS MODELS CONTINUE TO 
SHOW SOME SPREAD IN THE TRACK FORECAST BEYOND 36 HOURS. THE GFS 
MODEL CONTINUES TO CARRY FELICIA JUST NORTH OF THE ALOHA STATE. THE 
GFDL...ECMWF AND TVCN GO DOWN THE THE SPINE OF THE ISLAND CHAIN. 
NOGAPS...UKMET...HWRF AND TVCC APPEAR TO FAVOR A MORE SOUTHERN 
TRACK. WITH STRONG SHEAR OF 30 KT OR GREATER EXPECTED TO CONTINUE AT 
LEAST THROUGH THE NEXT 48 HOURS...IT IS EXPECTED THAT FELICIA WILL 
FOLLOW A GENERAL WESTWARD TRACK DURING THE NEXT COUPLE OF DAYS. 
SUBTLE ADJUSTMENTS WERE MADE TO THE PREVIOUS TRACK FORECAST. 
THEREFORE...THE LATEST TRACK FORECAST CONTINUES TO BRING FELICIA 
ACROSS THE MID-SECTION OF THE STATE. THIS MAY POTENTIALLY BRING 
FLOODING RAINS AND STRONG GUSTY WINDS TO MANY OF THE HAWAIIAN 
ISLANDS.
 
THE UPPER LEVEL DIFFLUENCE CONTINUES ACROSS FELICIA THIS EVENING. 
THIS CONTINUES TO SUPPORT THE DEEP CONVECTION NORTHEAST OF THE 
LOW-LEVEL CIRCULATION. ONCE FELICIA MOVES FAR ENOUGH WEST...IT IS 
STILL ASSUMED THAT IT WILL NO LONGER BE IN THIS AREA OF DIFFLUENCE 
ALOFT. THEREFORE...THE STRONG UPPER LEVEL WESTERLY WINDS WILL 
CONTINUE THE STRONG ENVIRONMENTAL VERTICAL WIND SHEAR. THE PRESENCE 
OF THIS VERY STRONG SHEAR IS STILL EXPECTED TO WEAKEN FELICIA 
DESPITE SLIGHTLY WARMING SSTS AND IMPROVED OCEAN HEAT CONTENT BEYOND 
48 HOURS ALONG THE FORECAST TRACK. THE CURRENT INTENSITY FORECAST 
FOLLOWS THE PREVIOUS PACKAGE...WHICH KEEPS FELICIA AT TROPICAL STORM 
INTENSITY THROUGH 48 HOURS. THIS AGAIN IS SIMILAR TO THE GFDL AND 
HWRF MODELS. HOWEVER...FELICIA MAY UNDERGO MORE RAPID WEAKENING 
THAN IS CURRENTLY FORECAST IF THE SHEAR ENDS UP TAKING A GREATER 
TOLL ON MONDAY.

IF THERE ARE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST TRACK 
AND INTENSITY...TROPICAL STORM WARNINGS WILL LIKELY BE REQUIRED FOR 
PORTIONS OF THE AREA CURRENTLY UNDER A TROPICAL STORM WATCH MONDAY 
MORNING.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/0900Z 21.0N 149.2W    45 KT
 12HR VT     10/1800Z 21.0N 150.9W    40 KT
 24HR VT     11/0600Z 21.0N 153.2W    35 KT
 36HR VT     11/1800Z 21.2N 155.4W    35 KT
 48HR VT     12/0600Z 21.4N 157.6W    35 KT
 72HR VT     13/0600Z 22.0N 161.6W    30 KT
 96HR VT     14/0600Z 22.9N 165.3W    25 KT...DISSIPATING
120HR VT     15/0600Z 25.0N 169.2W    20 KT...REMNANT LOW
 
$$
FORECASTER HOUSTON