Cyclone Season 2012: Tropical Cyclone Irina (Southern Indian Ocean) 29 February 2012 08h00 SAST

290300Z POSITION NEAR 16.3S 43.3E. TROPICAL CYCLONE (TC) 14S,(IRINA), LOCATED APPROXIMATELY 270 NM NORTHWEST OF ANTANANARIVO, MADAGASCAR, HAS TRACKED WESTWARD AT 01 KNOT OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS TC 14S IS OVERCOMING THE IMPEDIMENTS OF HIGH EASTERLY VERTICAL WIND SHEAR AND IS NOW INTENSIFYING OVER THE MOZAMBIQUE CHANNEL. THE CURRENT INTENSITY ANALYSIS IS BASED ON A COMBINATION OF AGENCY DVORAK ASSESSMENTS AND A PRESSURE REPORT FROM JUAN DE NOVA ISLAND, WHICH IS NEAR THE STORM CENTER. THE SYSTEM HAS BEEN DRIFTING WESTWARD OFF THE CAPE ST ANDRE REGION AND SLOWLY GATHERING STRENGTH. VERTICAL WIND SHEAR OVER THE LOW LEVEL CIRCULATION CENTER (LLCC) IS 20 TO 25 KNOTS, BUT ANIMATED WATER VAPOR IMAGERY SHOWS THE DEVELOPMENT OF A VIGOROUS OUTFLOW CHANNEL ON THE EQUATORWARD SIDE. POLEWARD OUTFLOW IS ALSO IMPROVING, ALTHOUGH THERE REMAINS A REGION OF PRONOUNCED SUBSIDENCE OVER THE SOUTHWEST QUADRANT. THAT IS ALSO REFLECTED IN TOTAL PRECIPITABLE WATER LOOPS, WHICH INDICATE A GENERAL LACK OF DEEP MOISTURE OVER THE CENTRAL AND SOUTHWEST MOZAMBIQUE CHANNEL. 28-29 DEGREE SEA SURFACE TEMPERATURES IN THE CHANNEL ARE SUPPORTIVE OF FURTHER INTENSIFICATION. PREVIOUS SCATTEROMETRY DATA INDICATED AN ELONGATED AND ILL-DEFINED LOW LEVEL CIRCULATION CENTER, BUT RECENT SATELLITE IMAGERY SHOWS BETTER ORGANIZATION AND TIGHTER BANDING. TC 14S IS IN A WEAK STEERING ENVIRONMENT BETWEEN A LOW- TO MID-LEVEL ANTICYCLONE NORTHEAST OF MADAGASCAR, WHICH IS ASSOCIATED WITH THE NEAR-EQUATORIAL RIDGE, AND THE NORTHWEST EXTENSION OF THE SUBTROPICAL RIDGE ALONG THE 30TH LATITUDE. THE NORTHERN ANTICYCLONE IS DEVELOPING INTO THE DOMINANT FORCE AND WILL DRIVE TC 14S ACROSS THE CHANNEL AND INTO MOZAMBIQUE, NORTH OF MAPUTO. PEAK INTENSITY WILL OCCUR BETWEEN TAU 48 AND 72 AS THE STORM MOVES THROUGH THE CENTER OF THE CHANNEL. THIS WARNING SUPERSEDES AND CANCELS REF A, JOINT TYPHOON WRNCEN 280121Z FEB 12 TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 280130). MAXIMUM SIGNIFICANT WAVE HEIGHT AT 290000Z IS 12 FEET.

- JTWC