000
WTPZ44 KNHC 192035
TCDEP4
TROPICAL STORM CELIA DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP042010
200 PM PDT SAT JUN 19 2010
 
CELIA'S APPEARANCE IN SATELLITE IMAGERY HAS CONTINUED TO IMPROVE
TODAY AS SEVERAL CURVED CONVECTIVE BANDS HAVE FORMED AND WRAPPED
AROUND THE LOW-LEVEL CIRCULATION CENTER. UPPER-LEVEL OUTFLOW HAS
ALSO IMPROVED IN ALL QUADRANTS EXCEPT TO THE EAST. THE INITIAL
INTENSITY OF 40 KT IS BASED ON A BLEND OF A SATELLITE INTENSITY
ESTIMATE OF T2.5/35 KT FROM BOTH TAFB AND SAB...ADT ESTIMATES OF
T2.9/43 KT FROM UW-CIMSS...AND A 3-HR AVERAGE OBJECTIVE ESTIMATE OF
T3.0/45 KT FROM NHC. HOWEVER...THE INITIAL INTENSITY COULD BE A
LITTLE LOW GIVEN CURRENT ORGANIZATIONAL TRENDS.
 
THE INITIAL MOTION ESTIMATE IS 265/06. THERE IS NO CHANGE TO
PREVIOUS FORECAST TRACK REASONING. ALL OF THE MODELS MAINTAIN A
STRONG MID-LEVEL RIDGE TO THE NORTH OF CELIA THROUGH 96 HOURS...AND
THEN ERODE THE WESTERN PERIPHERY OF THE RIDGE AFTER THAT TIME AS AN
UPPER-LEVEL TROUGH DIGS SOUTHWARD OFF THE WEST COAST OF THE U.S.
AND BAJA CALIFORNIA. THIS SCENARIO SHOULD ALLOW FOR CELIA TO
GRADUALLY GAIN LATITUDE BETWEEN 96-120 HOURS. THE GFS AND NOGAPS
MODELS DID NOT INITIALIZE CELIA VERY WELL AT 12Z...AND AS A RESULT
MUCH LESS WEIGHT WAS PLACED ON THOSE MODELS WHICH TAKE A MUCH WEAKER
CYCLONE SOUTHWESTWARD THROUGHOUT THE PERIOD. THE OFFICIAL TRACK
FORECAST IS CLOSE TO A BLEND OF THE UKMET...ECMWF...CANADIAN...
GFDL...AND HWRF MODELS.
 
CELIA IS SHOWING SIGNS OF POTENTIAL RAPID INTENSIFICATION BASED ON
THE INCREASE IN CONVECTIVE BANDING AND THE RECENT DEVELOPMENT OF A
SMALL CDO FEATURE. THE SHIPS INTENSITY MODEL SHARPLY INCREASES THE
VERTICAL SHEAR TO 20-25 KT THE NEXT 24 HOURS...BUT THIS APPEARS TO
BE DUE IN PART TO THE GFS MODEL'S POOR 12Z INITIALIZATION. THE
OTHER MODELS ONLY INDICATE 10-15 KT 200-MB WINDS ALONG CELIA'S
FORECAST TRACK AND THE LATEST UW-CIMSS SHEAR ANALYSIS SHOWS 5 KT OR
LESS OF VERTICAL SHEAR...COMPARED TO THE SHIPS-GFS ANALYSIS OF
10-15 KT.  GIVEN THE WEAK SHEAR AND CURRENT TRENDS...RAPID
INTENSIFICATION IS FORECAST FOR THE NEXT 24 HOURS OR SO...WITH A
LEVELING OFF BETWEEN 24-72 HOURS AS EASTERLY SHEAR IS EXPECTED TO
INCREASE. BY DAYS 4 AND 5...THE SHEAR IS EXPECTED TO RELAX AGAIN...
WHICH MAY ALLOW FOR SOME ADDITIONAL STRENGTHENING.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/2100Z 12.4N  98.0W    40 KT
 12HR VT     20/0600Z 12.3N  99.0W    55 KT
 24HR VT     20/1800Z 12.2N 100.4W    70 KT
 36HR VT     21/0600Z 12.2N 101.7W    75 KT
 48HR VT     21/1800Z 12.2N 103.0W    75 KT
 72HR VT     22/1800Z 12.3N 105.3W    75 KT
 96HR VT     23/1800Z 12.5N 107.5W    80 KT
120HR VT     24/1800Z 13.0N 110.5W    90 KT
 
$$
FORECASTER STEWART/BRENNAN