WDPN31 PGTW 220300 MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (FAXAI) WARNING NR 42// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 220000Z4 TO 250000Z7 DEC 01. A. SUPER TYPHOON (STY) 31W (FAXAI) IS LOCATED ABOUT 580 NM SOUTHEAST OF THE MARIANA ISLANDS. STY 31W HAS CONTINUED TO RAPIDLY OR EXPLOSIVELY DEEPEN DURING THE PAST 6 HOURS WHILE TRACKING WEST- NORTHWESTWARD AT 10 KNOTS. THE WARNING POSITION IS BASED ON 212330Z1 VISIBLE AND INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY OF 135 KNOTS IS BASED ON A BLEND OF DVORAK SATELLITE INTENSITY ESTIMATES OF 140 KT (T7.0) FROM JTWC AND 127 KT (T6.5) FROM AFWA. UPPER-LEVEL OUTFLOW REMAINS IMPRESSIVE AND UNRESTRICTED. B. STY 31W HAS BEEN TRACKING STEADILY WEST-NORTHWESTWARD FOR THE PAST 24 HOURS OR SO. NOGAPS CONTINUES ITS STRONG WEST BIAS AND, THEREFORE, HAS BEEN DISCOUNTED. THE AVN MODEL IS NO LONGER MOVING THE CYCLONE SHARPLY POLEWARD AND IS NOW CLOSER TO THE JTYM, JGSM, AND NEW UKMET CONSENSUS. THE SUBTROPICAL RIDGE IS EXPECTED TO REMAIN FAIRLY STRONG TO THE NORTH OF STY 31W THROUGH 36-48 HOURS, WHICH SHOULD ACT TO KEEP THE CYCLONE ON A GENERAL WEST-NORTHWESTWARD OR NORTHWESTWARD TRACK UNTIL IT NEARS THE CENTRAL OR NORTHERN MARIANA ISLANDS IN ABOUT 48 HOURS. THE LONGWAVE TROUGH OVER EASTERN ASIA IS FORECAST TO DIG SLOWLY SOUTHEASTWARD ACROSS THE WESTERN PACIFIC OCEAN AND GRADUALLY ERODE THE WESTERN PORTION OF THE SUBTROPICAL RIDGE. THE TIMING AND AMOUNT OF RIDGE EROSION WILL DETERMINE WHETHER OR NOT STY 31W RECURVES THROUGH OR EAST OF THE MARIANA ISLANDS. SINCE THE POLAR JET IS EXPECTED TO BE MORE ZONAL TO THE NORTH OF THE CYCLONE, A MORE WESTWARD FORECAST THROUGH THE CENTRAL OR NORTHERN MARIANA ISLANDS BEFORE RECURVATURE BEGINS APPEARS TO BE A REASONABLE SCENARIO AT THIS TIME. C. THE OBVIOUS QUESTION IS: HOW MUCH STRONGER CAN STY 31W BECOME? THE CYCLONE HAS BEEN RAPIDLY OR EXPLOSIVELY DEEPENING FOR THE PAST 30 HOURS OR SO. IT HAS ALSO GONE THROUGH AT LEAST ONE EYEWALL REPLACEMENT CYCLE LAST NIGHT AND MICROWAVE IMAGERY SUGGESTS THAT IT MAY BE ABOUT TO BEGIN ANOTHER REPLACEMENT CYCLE WHICH WOULD RESULT IN SHORT-TERM WEAKENING. HOWEVER, THE VERY FAVORABLE UPPER-LEVEL OUTFLOW PATTERN SUGGESTS THAT SOME ADDITIONAL STRENGTHENING IS STILL POSSIBLE AND 150 KT IS NOT UNREALISTIC. CLIMATOLOGY SUGGESTS THAT STY 31W SHOULD PEAK BY 24 HOURS WITH SLOW WEAKENING AFTER THAT. BY 36-48 HOURS, INCREASING SOUTHWESTERLY SHEAR MAY BEGIN TO DISRUPT THE INNER-CORE CONVECTION AND START A SLOW WEAKENING TREND, AS NOTED IN THE FORECAST. D. WIND RADII ARE BASED ON CLIMATOLOGY FOR A SMALLER THAN AVERAGE SIZE TROPICAL CYCLONE. NOTE: AFTER 15 YEARS AND 7 MONTHS AND ISSUING OVER 1000 WARNINGS ON MORE THAN 170 TROPICAL CYCLONES AT JTWC GUAM AND PEARL HARBOR, THIS WILL BE MY LAST WARNING AS A RESERVE TYPHOON DUTY OFFICER. A SPECIAL THANKS TO ALL OF THE USERS WHO HAVE ENDURED MY LENGTHY PROG REASONINGS OVER THE YEARS. RESPECTFULLY, CDR STACY R. STEWART, USNR. FORECAST TEAM: STEWART/LEEJOICE/BRYANT/MAYER/TON// BT #XXXX NNNN