Typhoon 03W(GUCHOL) peaking by 24h at CAT 2 US// TC 02A(BIPARJOY) may reach CAT 3 US by 36h//0803utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TY 03W(GUCHOL) AND ON TC 02A(BIPARJOY).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LARGE CLUSTER OF PERSISTENT DEEP CONVECTION OVER THE EASTERN SEMICIRCLE WITH SPIRAL CONVECTIVE BANDS WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON AGENCY POSITION FIXES ALONG WITH THE MSI WHICH SHOWS A BANDING EYE FEATURE. A 072210Z SSMIS 91GHZ IMAGE SHOWED A MICROWAVE EYE FEATURE, WITH STRONG CONVECTIVE BANDS WRAPPING ON THE EASTERN PERIPHERY OF THE LLCC. THE INITIAL INTENSITY IS ASSESSED AT 65 KTS BASED ON A COMBINATION OF OBJECTIVE AND SUBJECTIVE DVORAK INTENSITY ESTIMATES RANGING FROM T3.0 (45 KTS) TO T4.5 (77 KTS). ADDITIONALLY, AN EARLIER 072105Z SMAP WINDSPEED IMAGE SHOWS A BROAD SWATH OF 60-65 KNOTS ON THE NORTHERN SEMICIRCLE. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE WITH MODERATE EASTWARD OUTFLOW AND LOW VERTICAL WIND SHEAR (VWS) AS WELL AS WARM SEA SURFACE TEMPERATURES (SSTS) AND HIGH OCEAN HEAT CONTENT (OHC).

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: OVERALL, OVER THE PAST SIX HOURS TYPHOON 03W HAS REMAINED ON A STEADY WEST-NORTHWESTWARD TRACK ALONG THE SOUTHWESTERN PERIPHERIES OF THE SUBTROPICAL RIDGE (STR) TO THE NORTHEAST AND A NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTH. AFTER TAU 24, TY 03W IS EXPECTED TO TURN AND TRACK NORTH-NORTHWESTWARD, AS A MAJOR SHORTWAVE TROUGH MOVING OVER JAPAN WILL CREATE A BREAK IN THE STR TO THE NORTH. ADDITIONALLY, THE STR NEAR 30N 160E IS EXPECTED TO AMPLIFY. AS A RESULT, THE SYSTEM WILL RAPIDLY TURN POLEWARD AND ACCELERATE NORTHEASTWARD ALONG THE WESTERN PERIPHERY OF THE STR THROUGHOUT THE FORECAST. IN TERMS OF INTENSITY, 03W WILL CONTINUE TO RAPIDLY INTENSIFY OVER THE NEXT 36 HOURS, UNDER FAVORABLE CONDITIONS CHARACTERIZED BY ROBUST OUTFLOW, LOW VWS, WARM SSTS. THIS WILL ALLOW THE SYSTEM TO REACH A PEAK INTENSITY OF NEAR 90 KNOTS AT TAU 24. AFTER TAU 24, A COMBINATION OF COOLER SSTS, INCREASING NORTHWESTERLY VWS, AND CONSTRICTED OUTFLOW ALOFT, WILL COMBINED TO SLOWLY WEAKEN THE SYSTEM. BY TAU 120, THE SYSTEM IS EXPECTED TO BEGIN SUBTROPICAL TRANSITION.

MODEL DISCUSSION: NUMERICAL TRACK GUIDANCE REMAINS IN GOOD AGREEMENT ON THE OVERALL RECURVE SCENARIO BUT CONTINUES TO SHOW LARGE CROSS TRACK SPREAD IN THE LATER TAUS. THE JTWC TRACK FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH 48 HOURS WITH HIGH CONFIDENCE AS THERE IS ONLY A 73 NM SPREAD IN MANY OF THE CONSENSUS MEMBERS. AFTER TAU 48, MODEL SPREAD INCREASES WITH GFS AND NAVGEM MAKING UP THE EASTERN EDGE OF THE ENVELOPE, WHILE JGSM AND UEM2 MAKE UP THE WESTERN OUTLIER. BEYOND TAU 48, CONFIDENCE REMAINS MEDIUM DUE TO THE LARGE SPREAD IN TRACK GUIDANCE. THE JTWC INTENSITY FORECAST IS PLACED SLIGHTLY ABOVE CONSENSUS THROUGH TAU 48 DUE TO THE EXPECTED INTENSIFICATION TREND AND MULTIPLE RAPID INTENSIFICATION (RI) AIDS BEING TRIGGERED. THE INTENSITY FORECAST LIES NEAR CONSENSUS THROUGH THE REMAINDER OF THE FORECAST WITH MEDIUM CONFIDENCE.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A CYCLONE BEING SHEARED BY MODERATE EASTERLY VERTICAL WIND SHEAR (VWS), WITH A RAGGED MASS OF DEEP CONVECTION DISPLACED LARGELY SOUTHWEST OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A COMBINATION OF AGENCY POSITION FIXES. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A COMBINATION OF OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES. THE SYSTEM CONTINUES TO TRACK TOWARD THE NORTHWEST ON THE WESTERN PERIPHERY OF AN EXTENSION OF THE SUBTROPICAL RIDGE (STR) OVER INDIA. ENVIRONMENTAL ANALYSIS IS ASSESSED AS MARGINAL, WITH GOOD MODERATE POLEWARD AND EQUATORWARD OUTFLOW ALOFT, WARM SEA SURFACE TEMPERATURES (SSTS) RANGING (29-30C) OFFSET BY MODERATE EASTERLY VERTICAL WIND SHEAR (VWS) WHICH IS TILTING THE SYSTEM WESTWARD.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 02A (BIPARJOY) IS EXPECTED TO CONTINUE TRACKING NORTH-NORTHWESTWARD AS A SHORTWAVE TROUGH PASSES TO THE NORTH WHILE A RIDGE BUILDS OVER INDIA. BY TAU 36, THE SYSTEM WILL PICK UP SPEED AS THE RIDGE OVER INDIA IS EXPECTED TO BECOME THE DOMINANT STEERING FEATURE. AFTER TAU 48, 02A WITH TRACK NORTHWESTWARD THROUGH THE REMAINDER OF THE FORECAST, AS THE RIDGE STRENGTHENS AND ELONGATES TO A NORTHWEST-SOUTHEAST ORIENTATION. TROPICAL CYCLONE 02A CONTINUES TO BATTLE EASTERLY VWS. WHICH EXPLAINS WHY 02A HAS STRUGGLED TO MAKE SIGNIFICANT GAINS IN INTENSITY OVER THE PAST 12 HOURS. HOWEVER, 02A IS FORECAST TO INTENSIFY TO A PEAK OF 95-100 KNOTS OVER THE NEXT 24-36 HOURS. HOWEVER, AFTER TAU 36, THE SYSTEM IS EXPECTED TO STEADILY WEAKEN DUE TO MULTIPLE NEGATIVE FACTORS, SUCH AS INCREASING VWS, AND DECREASED OUTFLOW ALOFT. AFTER TAU 72, FURTHER WEAKENING IS EXPECTED AS A RESULT OF DRY AIR ENTRAINMENT.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE CONTINUES TO SHOW A BIFURCATION, BETWEEN THE UKMET, GALWEM, AND ECMWF TRACKING THE SYSTEM ON THE RIGHT OF THE GUIDANCE ENVELOPE. WHILE THE GFS, NAVGEM, AND THE GFS ENSEMBLE MEAN MAKE UP WESTERN PERIPHERY OF THE GUIDANCE ENVELOPE TURNING TOWARD THE ARABIAN PENINSULA BY THE LATER TAUS. ADDITIONALLY, ENSEMBLE MEMBERS FOR BOTH GFS AND ECMWF CONTINUES TO SHOW A HIGH DEGREE OF UNCERTAINTY WITH LARGE SPREAD ESPECIALLY IN THE LATER TAUS AS WELL. THEREFORE, THE JTWC TRACK FORECAST IS PLACED WITH LOW CONFIDENCE BASED ON THE UNCERTAINTY IN THE TRACK GUIDANCE. THE INTENSITY GUIDANCE IS MIXED, WITH RAPID INTENSIFICATION (RI) GUIDANCE BEING TRIGGERED ALONG WITH THE HWRF SHOWING AN INTENSIFICATION PHASE UP TO 110 KNOTS. WHILE GFS CONTINUES TO REPRESENT THE LOW END OF THE INTENSITY GUIDANCE ENVELOPE, WITH A PEAK OF 90 KNOTS. THE JTWC INTENSITY FORECAST IS PLACED WITH LOW CONFIDENCE AND CLOSE TO THE MULTI-MODEL CONSENSUS.