Western Pacific: Invest 92W is now TD 22W, 2 new disturbances over the Philippine Sea, 07/06utc

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TD 22W IS TRACKING SLOWLY WITHIN A COMPETING STEERING ENVIRONMENT AND IS EXPECTED TO TRACK SLOWLY NORTHWESTWARD TO NORTH-NORTHWESTWARD THROUGH 36H THEN TURN WESTWARD THROUGH 72H AS THE LOW- TO MID-LEVEL STR BECOMES THE PRIMARY STEERING INFLUENCE. CONDITIONS SHOULD REMAIN FAVORABLE THROUGH 24H WITH A PEAK INTENSITY OF 40 KNOTS FORECAST AT 24H, POSSIBLY SLIGHTLY HIGHER NEAR THE LANDFALL TIME. AFTER 24H, INTERACTION WITH LAND IS EXPECTED TO HINDER DEVELOPMENT WITH GRADUAL WEAKENING ANTICIPATED AS THE SYSTEM TRACKS ACROSS HAINAN ISLAND. AS THE SYSTEM EMERGES OVER THE GULF OF TONKIN AFTER 48H, REINTENSIFICATION IS UNLIKELY DUE TO LAND INTERACTION AND INCREASING NORTHEASTERLY VERTICAL WIND SHEAR. AFTER 72H, TD 22W WILL TURN SOUTHWESTWARD UNDER A NORTHEAST-SOUTHWEST ORIENTED STR. THE SYSTEM IS EXPECTED TO DISSIPATE BY 96H AS IT TRACKS INLAND OVER MOUNTAINOUS TERRAIN.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL DEPRESSION (TD) HAS SLOWLY CONSOLIDATED OVER THE PAST TWELVE HOURS AND HAS TRANSITIONED FROM A MONSOON DEPRESSION INTO A WARM-CORE TROPICAL SYSTEM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS EXPOSED LOW-LEVEL CLOUD LINES WRAPPING INTO A BROAD CENTER WITH PERSISTENT CORE CONVECTION. A 070541Z AMSR2 89GHZ IMAGE REVEALS FORMATIVE CURVED BANDING PRIMARILY OVER THE EASTERN SEMICIRCLE WITH A RAGGED CENTER. A 070236Z ASCAT-B IMAGE INDICATES THE WIND FIELD HAS STRENGTHENED AND CONTRACTED WITH 25-30 KNOT WINDS WRAPPING IN CLOSER TO CENTER WITH A 130KM RADIUS OF MAXIMUM WINDS, WHICH IS MORE TYPICAL OF A TROPICAL SYSTEM. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE ASCAT-B IMAGE. THE INITIAL INTENSITY OF 30 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE ASCAT DATA BUT IS HEDGED SLIGHTLY HIGHER THAN THE AGENCY DVORAK ESTIMATES. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE WITH MODERATE POLEWARD AND EQUATORWARD OUTFLOW AND LOW (5-10KT) VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES OF 29-30C ARE CONDUCIVE.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH 72H WITH A 130KM SPREAD IN SOLUTIONS AT 72H BUT DIVERGE AFTER 72H WITH A LARGE SPREAD AND INCREASED UNCERTAINTY LENDING LOW CONFIDENCE TO THE JTWC FORECAST TRACK. THE JTWC FORECAST TRACK IS POSITIONED NEAR THE MULTI-MODEL CONSENSUS (CONW). INTENSITY GUIDANCE INDICATES A PEAK RANGING FROM 35 TO 45 KNOTS AT 24H WITH STEADY WEAKENING THROUGH THE REMAINDER OF THE FORECAST PERIOD.

AN AREA OF CONVECTION (INVEST 93W) HAS PERSISTED NEAR 13.1N 131.4E, APPROXIMATELY 830KM WEST-NORTHWEST OF YAP. THIS SYSTEM IS EMBEDDED WITHIN THE WESTERN PERIPHERY OF A MONSOON DEPRESSION WITH STRONG, CONVERGENT LOW-LEVEL WESTERLIES OVER THE SOUTHERN SEMICIRCLE. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN ELONGATED DISTURBANCE WITH BROAD TURNING AND MULTIPLE VORTEXES. MSI ALSO INDICATES A MID-LEVEL CIRCULATION CENTER NEAR 13.7N 129.0E, HOWEVER, THERE IS NO EVIDENCE OF A DEFINED LOW LEVEL CENTER AT THIS TIME. UPPER- LEVEL ANALYSIS INDICATES A GENERALLY FAVORABLE ENVIRONMENT WITH GOOD EQUATORWARD OUTFLOW AND LOW TO MODERATE VERTICAL WIND SHEAR. GLOBAL MODELS INDICATE THIS MONSOON DEPRESSION WILL GRADUALLY CONSOLIDATE INTO A TROPICAL STORM OVER THE NEXT 2-3 DAYS AS INVEST 93W MERGES WITH INVEST 94W. THERE IS SIGNIFICANT UNCERTAINTY IN HOW THESE TWO SYSTEMS WILL DEVELOP AND MERGE WITH HIGH UNCERTAINTY IN TRACK MOTION AS WELL. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 12 TO 18 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

AN AREA OF CONVECTION (INVEST 94W) HAS PERSISTED NEAR 15.5N 137.7E, APPROXIMATELY 795 KM NORTH-NORTHWEST OF GUAM. THIS SYSTEM IS EMBEDDED WITHIN THE NORTHEASTERN PERIPHERY OF A MONSOON DEPRESSION WITH STRONG, CONVERGENT LOW-LEVEL SOUTHWESTERLIES OVER THE SOUTHERN SEMICIRCLE. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS MULTIPLE VORTEXES ROTATING AROUND A CENTROID WITH DISORGANIZED DEEP CONVECTION ASSOCIATED WITH THE CONVERGENT SOUTHWESTERLY FLOW SHEARING OVER THE SOUTHEAST QUADRANT DUE TO MODERATE TO STRONG (20-30 KNOTS) NORTHWESTERLY VERTICAL WIND SHEAR AND BROAD EQUATORWARD OUTFLOW. DESPITE THE MARGINAL CONDITIONS, A 070401Z AMSR2 89GHZ COMPOSITE REVEALS SOME FRAGMENTED, SHALLOW BANDING WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION CENTER. GLOBAL MODELS INDICATE THIS MONSOON DEPRESSION WILL GRADUALLY CONSOLIDATE INTO A TROPICAL STORM OVER THE NEXT 2-3 DAYS AS INVEST 93W MERGES WITH INVEST 94W. THERE IS SIGNIFICANT UNCERTAINTY IN HOW THESE TWO SYSTEMS WILL DEVELOP AND MERGE WITH HIGH UNCERTAINTY IN TRACK MOTION AS WELL. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 12 TO 18 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

07/1545UTC.