Activity at last: TD 06W(SONGDA)// TC 01S // TS 07E(FRANK)//TS 08E(GEORGETTE)// Invest 95W, 29/09utc

JTWC IS ISSUING 6HOURLY WARNINGS ON 06W(SONGDA) AND 12HOURLY WARNINGS ON 01S. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON BOTH SYSTEMS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS BROAD EAST-WEST ELONGATED DEEP FLARING CONVECTION PARTIALLY OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC) MOVING ALONG THE NORTHERN PERIPHERY OF A MONSOON GYRE. A 290413Z AMSR2 89GHZ MICROWAVE IMAGE INDICATES A BULK OF THE CONVECTIVE STRUCTURES LIE ALONG THE AXIS OF STORM MOTION WITH WEAK RETURN FLOW INDICATED TO THE SOUTH OF THE LLCC. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE ELONGATED NATURE OF THE SYSTEM SEEN IN BOTH THE MSI AND AMSR2 IMAGING. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AGREEMENT BETWEEN PGTW DVORAK INTENSITY ESTIMATES AND CIMSS ADT WHICH BOTH REFLECT 30 KNOTS, WHILE RJTD REMAINS SLIGHTLY HIGHER AT 35KTS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 06W (SONGDA) HAS TRACKED WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO ITS NORTH. THROUGH TAU 36 THE SYSTEM IS FORECAST TO CONTINUE ITS WEST-NORTHWESTWARD TRAJECTORY IN AN OVERALL FAVORABLE ENVIRONMENT. THE MAIN HINDRANCE TO INTENSIFICATION IS THE LACK OF A COHESIVE LOW LEVEL CIRCULATION DUE TO THE FACT THAT THIS SYSTEM LIES ALONG THE NORTHERN PERIPHERY OF THE MONSOON GYRE WHICH IS SLOWING THE CONSOLIDATION OF THE LOW LEVEL CORE. THE STR WHICH WAS PREVIOUSLY FORECAST TO STEER THE SYSTEM JUST NORTH OF SHANGHAI, IS NOW SHOWING SIGNS OF DETERIORATION AS A SHORT WAVE TROUGH MOVES IN FROM THE NORTHWEST. THIS DEGRADATION OF THE STEERING RIDGE IN THE LATER TAUS COULD ALLOW THE SYSTEM TO FOLLOW A MORE NORTHWESTWARD TRACK INTO THE SOUTHWESTERN REGION OF THE YELLOW SEA AND EVENTUALLY DISSIPATE CLOSER TO QINGDAO NEAR TAU 96.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT THE STEERING RIDGE TO THE NORTH OF THE SYSTEM WILL BREAK DOWN ALLOWING THE SYSTEM TO TRACK FURTHER NORTH, THE MAGNITUDE AND TIMING OF THIS NEW TREND IS NOT CLEAR AT THIS TIME. FOR THIS REASON THE JTWC TRACK FORECAST IS PLACED WITH MEDIUM CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT AN INITIAL INTENSIFICATION TREND IS POSSIBLE THROUGH TAU 12 TO TAU 24, WITH ONLY DECAY-SHIPS (GFS VERSION) SHOWING AN UNREALISTIC CLIMB TO NEARLY 50 KNOTS. AFTER TAU 24 THE BULK OF THE GUIDANCE THEN BEGINS TO STAGNATE NEAR 35 KNOTS AND EVENTUALLY DECAYS THE SYSTEM UNTIL DISSIPATION NEAR TAU 96. FOR THIS REASON THE JTWC INTENSITY FORECAST IS PLACED WITH HIGH CONFIDENCE.

THE AREA OF CONVECTION (INVEST 95W) PREVIOUSLY LOCATED NEAR 21.3N 130.8E IS NOW LOCATED NEAR 21.5N 130.1E, APPROXIMATELY 318 NM SOUTH-SOUTHEAST OF KADENA, AB. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 290540Z HIMAWARI INFRARED IMAGE DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH DISORGANIZED FLARING CONVECTION ON THE PERIPHERY OF THE CIRCULATION TO THE SOUTH AND TO THE NORTHEAST. INVEST 95W IS THE ANCHOR POINT OF A MONSOON GYRE FEATURE WHICH IS MOVING TO THE NORTH, WITH A BROAD BAND OF ENHANCED WIND FLOW TO THE SOUTH, EXTENDING UP TO THE NORTHEAST PERIPHERY. THE ENVIRONMENT IS RELATIVELY FAVORABLE FOR DEVELOPMENT WITH LOW (5-10KTS) VERTICAL WIND SHEAR, HIGH SEA SURFACE TEMPERATURES (SSTS), BUT AT PRESENT OUTFLOW IS RELATIVELY RESTRICTED TO A WEAK EASTWARD OR POLEWARD FLOW, WITH SOME PRESSURE COMING FROM THE UPPER-LEVEL POINT SOURCE TO THE SOUTHWEST IMPINGING ON THE OUTFLOW A BIT. DETERMINISTIC AND ENSEMBLE MODELS ARE IN GENERALLY FAIR AGREEMENT THE SYSTEM WILL TRACK NORTHWEST OVER THE NEXT 48-72 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 13 TO 17 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP PERSISTENT CONVECTION PARTIALLY OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC) WITH TRANSVERSE BANDING ON ITS WESTERN SEMICIRCLE. A 290333Z METOP-C ASCAT IMAGE SHOWS A SMALL, SLIGHTLY ELONGATED LLCC WITH A LARGE SWATH OF 35 KNOT WINDS WRAPPING INTO THE WESTERN SEMICIRCLE WITH A FEW ISOLATED 40 KNOT WIND BARBS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI AND ASCAT IMAGERY. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE RECENT ASCAT IMAGERY.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 01S IS IN THE PROCESS OF EXECUTING A SOUTHWESTWARD TURN UNDER THE STEERING INFLUENCE OF A STR TO ITS EAST. THE SYSTEM IS FORECAST TO TRACK GENERALLY SOUTHWESTWARD OVER THE NEXT 24 HOURS IN WHICH TIME THE SYSTEM MAY REACH ITS PROJECTED PEAK INTENSITY OF 45 KNOTS. AFTER TAU 24, THE SYSTEMS UPPER LEVEL OUTFLOW WILL BEGIN TO DECLINE, RESULTING IN STAGNATING INTENSITIES AS VERTICAL WIND SHEAR (VWS) BEGINS TO COUNTERACT OUTFLOW. BETWEEN TAU 36 AND TAU 48 VWS INCREASES AND DRY AIR ENTRAINMENT BEGINS TO ADD TO THE SYSTEMS DECLINING ENVIRONMENT. AFTER TAU 48 AS THE SYSTEMS CONTINUES WEAKENING ITS STEERING MECHANISM WILL TRANSLATE TO THE LOWER LEVEL WIND FIELD ASSOCIATED WITH A MID-LEVEL ANTI-CYCLONE POLEWARD OF THE SYSTEM. EVENTUALLY STEADING UP ON A GENERALLY WEST-NORTHWESTWARD COURSE THE SYSTEM WILL BEGIN TO MOVE INTO AN ENVIRONMENT WHICH WILL BE MUCH LESS CONDUCIVE FOR FURTHER DEVELOPMENT AS VERTICAL WIND SHEAR INCREASES ALONG WITH A SUBSTANTIAL IN FLUX OF DRY AIR, UNTIL EVENTUAL DISSIPATION NEAR TAU 96.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH THE JTWC FORECAST THROUGH TAU 48 WITH THE EXCEPTION OF NAVGEM AND HWRF WHICH SHOW AN UNREALISTIC EASTWARD TRACK INTO THE STEERING RIDGE BEFORE RETURNING WESTWARD. AFTER TAU 48 NUMERICAL MODELS BEGIN TO SPREAD SLIGHTLY AS CROSS TRACK AND ALONG TRACK VARIABILITY BEGIN TO ACCUMULATE. FOR THIS REASON THE JTWC FORECAST TRACK IS PLACED WITH MEDIUM CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN GENERALLY GOOD AGREEMENT WITH THE JTWC FORECAST WITH THE BULK OF THE MODELS SHOWING A GENERAL INCREASE THROUGH TAU 12 AFTER WHICH ALL MEMBERS BEGIN A DOWNWARD TREND THROUGH THE FORECAST PERIOD. COAMPS-TC (NAVGEM) AND AHNI (GFS) BOTH INDICATE AN IMMEDIATE WEAKENING TREND THAT IS INCONGRUOUS WITH THE BULK OF THE GUIDANCE. FOR THIS REASON THE JTWC FORECAST INTENSITY IS PLACED WITH MEDIUM CONFIDENCE.

Tropical Storm Frank Discussion Number 13 NWS National Hurricane Center Miami FL EP072022 300 AM MDT Fri Jul 29 2022 Although there has been an increase in banding over the eastern semicircle of Frank overnight, some entrainment of dry air over the northwestern portion of the circulation appears to have temporarily caused a pause in the recent intensification. Frank's outflow has become better established, and the latest shear analysis from UW/CIMSS shows that the shear has decreased to less than 10 kt. Recent scatterometer data was very helpful in pinpointing the center and it revealed maximum winds of around 45 kt. The ASCAT data also indicated that the wind field has expanded over the eastern semicircle. Subjective satellite intensity estimates from TAFB and SAB are 55 and 65 kt, respectively. The advisory intensity has been kept at 55 kt, in line with the TAFB classification and allowing for some undersampling of the ASCAT satellite. Although the vertical shear over Frank has diminished, the lack of an inner core in recent microwave imagery and the fairly large wind field suggest it may take a little more time before the rate of strengthening increases. The SHIPS RI and DTOPS guidance gives about a 50/50 shot of rapid strengthening over the next 24 hours, however the NHC foreast is slightly below that given the above mentioned structure of the storm. The NHC forecast still calls for Frank to become a hurricane later today, and steady strengthening is likely through 36 hours. By 48 hours, Frank will be moving over progressively cooler water and into a more stable environment. This will lead to steady weakening, and Frank is forecast to become a post-tropical cyclone by day 5. Frank is moving west-northwestward or 295/9 kt. The storm is currently being steered around the southwestern periphery of a subtropical ridge near northwestern Mexico. A weakness is forecast to develop in the ridge over the next couple of days which will cause Frank to turn more poleward. The spread in the dynamical models has continued to decrease and the latest NHC forecast track is near the center of the tightly clustered guidance envelope. It again should be noted that Frank and Tropical Storm Georgette are expected to come close enough to one another for some interaction. Frank will be the larger and dominant system during this interaction, and Georgette will have little impact on the track or intensity of Frank.

Tropical Storm Georgette Discussion Number 8 NWS National Hurricane Center Miami FL EP082022 200 AM PDT Fri Jul 29 2022 There has been little change in Georgette's structure overnight. Earlier microwave imagery and more recent geostationary satellite data continue to suggest that the cyclone's low-level center is located near the eastern side of the primary convective mass. This is due to moderate easterly shear. Dvorak satellite intensity estimates remained unchanged, and therefore still support an initial wind speed of 45 kt. The cyclone is moving south of due west, or 260 degrees at 9 kt. Georgette is forecast to move west-southwestward to southwestward with a deceleration in forward speed as the much larger and stronger Tropical Storm or Hurricane Frank passes to the northeast. The latest dynamical model guidance shows Georgette moving farther westward in the next 36 to 48 hours, before the storm stalls when Frank finally passes Georgette's longitude. After that time, the guidance takes the smaller tropical cyclone (Georgette) northeastward in the flow around the southeastern side of Frank. Most of the models keep Georgette separate for the next 3 to 4 days, but there has been a significant increase in the spread of guidance tonight, and the uncertainty in the track forecast is unusually large. The official forecast has been adjusted westward through 48 hours to be in better agreement with the various track aids. After that time, the forecast is a blend of the GFS ensemble mean and the HFIP corrected consensus. Moderate easterly to northeasterly shear is forecast to continue over Georgette during the next few days. This is likely to result in little overall change in strength through 36 hours. After that time, the official forecast calls for some weakening as the vertical shear is forecast to increase. Although the NHC forecast calls for Georgette to dissipate in 4 to 5 days, some of the guidance suggests that this could occur sooner.