Prog
Posted by
JAC on 10/8/2009, 10:46 am
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 21W//
WARNING NR 01//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. RECENT ANIMATED INFRARED IMAGERY SHOWS DEEP CONVECTION HAS
BEEN WRAPPING INTO A WELL ORGANIZED LOW LEVEL CIRCULATION CENTER
(LLCC) AS EVIDENCED BY A 080913Z QUIKSCAT PASS. OVER THE PAST 12
HOURS TD 21W HAS SEEN SIGNIFICANT IMPROVEMENT TO THE OVERALL STRUC-
TURE. BANDING CONVECTION HAS DEVELOPED OVER THE LLCC WITH THE DEEPEST
CONVECTION LOCATED ON THE EASTERN PERIPHERY AND WRAPPING INTO THE
NORTHERN PORTION OF THE LLCC. A 080945Z SSMIS IMAGE SHOWS THE BANDING
CONVECTION WRAPPING INTO THE LLCC. UPPER LEVEL ANALYSIS INDICATES
THERE IS GOOD DIFFLUENCE ABOVE THE LLCC, WITH A TROPICAL UPPER TROPO-
SPHERIC TROUGH (TUTT) CELL TO THE EAST, AND TO THE NORTHWEST, HELPING
TO SUPPORT THE UPPER LEVEL OUTFLOW. HOWEVER, THE TUTT CELL TO THE
NORTHWEST IS BEGINNING TO BE ABSORBED INTO THE TAIL END OF A COLD
FRONT ASSOCIATED WITH THE REMNANTS OF EXTRATROPICAL (ET) STORM 20W
(MELOR). VERTICAL WIND SHEAR IS CURRENTLY AT LOW TO MODERATE LEVELS
OVER TD 21W.
3. FORECAST REASONING
A. THIS IS THE FIRST PROGNOSTIC REASONING BULLETIN FOR TD 21W,
ESTABLISHING THE FORECAST PHILOSOPHY.
B. TD 21W WILL CONTINUE TO TRACK ALONG THE WESTERN EDGE OF A MID-
LEVEL SUBTROPICAL RIDGE (STR). AS THE REMNANTS OF ET 20W MOVES EAST-
WARD OVER THE NORTHERN PACIFIC, THE STR IS EXPECTED TO REMAIN IN THE
CURRENT ORIENTATION. AS ET 20W MOVES OUT OF THE PACIFIC THE STR WILL
RE-ORIENT ITSELF, EXTENDING WESTWARD. HOWEVER, BY THIS TIME (TAU 48),
TD 21W WILL BE NORTH OF THE RIDGE AXIS AND WILL BEGIN TO SHIFT TO A
NORTHEASTWARD TRACK AROUND IWO TO. THE TRACK SPEED WILL CONTINUE TO
INCREASE OVER THE FORECAST PERIOD, ENHANCED BY THE TROUGH EXTENDING
SOUTH FROM ET 20W.
C. BEYOND TAU 72, TD 21W WILL CONTINUE TRACKING NORTHEASTWARD
AROUND THE STR, INCREASING SPEED AS A MID-LATITUDE LOW PRESSURE
SYSTEM TRACKS INTO THE PACIFIC, CAPTURING TD 21W BETWEEN TAU 72 AND
96. EXTRATROPICAL TRANSITION IS EXPECTED TO BEGIN AROUND TAU 96, WITH
THE COMPLETE TRANSITION OCCURRING BY TAU 120. MODEL GUIDANCE IS IN
POOR AGREEMENT REGARDING THE FORECAST TRACK AND INTENSITY, BUT A
MAJORITY OF THE MODELS SHOW A CONTINUED TRACK TO THE NORTH-NORTHWEST
WITH A NORTHEASTWARD RECURVATURE.//
NNNN
|
21
In this thread:
Next WPAC Bad-Boy: 92W -
JAC,
10/7/2009, 11:53 am- TS Nepartak - JAC, 10/9/2009, 9:42 am
- Three high rollers - JAC, 10/8/2009, 9:24 pm
- Now TD21W - JAC, 10/8/2009, 9:34 am
- TCFA - JAC, 10/8/2009, 7:11 am
- Re: Next WPAC Bad-Boy: 92W - hanna, 10/7/2009, 9:41 pm
Post A Reply
This thread has been archived and can no longer receive replies.