Tropical Cyclone Four (Arabian Sea)

TROPICAL CYCLONE (TC) 04A, LOCATED APPROXIMATELY 525 NM EAST-
SOUTHEAST OF CAPE GUARDAFUI, SOMALIA, HAS TRACKED WESTWARD AT 17
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS IMPROVED AND DEEPENED CONVECTIVE BANDING ALONG THE
NORTHERN PERIPHERY OF A WELL-DEFINED LOW LEVEL CIRCULATION CENTER.
ADDITIONALLY, A NEW RAIN BAND HAS FORMED ALONG THE SOUTHWEST
QUADRANT. THE INITIAL POSITION WAS BASED ON THE ABOVE ANIMATION AND
EXTRAPOLATED FROM A 222123Z AMSU-B MICROWAVE IMAGE WITH FAIR
CONFIDENCE. THE INITIAL INTENSITY WAS BASED ON THE HIGH END OF DVORAK
ESTIMATES FROM PGTW, KNES, AND DEMS. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH THE RIDGE AXIS DIRECTLY OVERHEAD CREATING
EXCELLENT POLEWARD OUTFLOW AND LOW (05-10 KNOT) VERTICAL WIND SHEAR.
THIS IS ALSO DISCERNIBLE IN RECENT ANIMATED WATER VAPOR IMAGERY.



 abiosair BASE-IMG5-2.04A io0412 na201204
CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A LOW- TO
MID-LAYERED SUBTROPICAL RIDGE TO THE NORTH. TC 04A IS EXPECTED TO
CONTINUE ALONG THIS TRACK BEFORE IT MAKES LANDFALL ALONG NORTHERN
SOMALIA COAST AFTER TAU 48. THE SYSTEM WILL SLIGHTLY INTENSIFY,
PEAKING AT 55 KNOTS BEFORE LANDFALL, DUE TO THE SUSTAINED FAVORABLE
UPPER LEVEL ENVIRONMENT. THE LIMITED NUMERICAL GUIDANCE IS IN GOOD
AGREEMENT UP TO LANDFALL, AFTER WHICH, THE MODELS DIVERGE WITH SOME
INDICATING A RECURVATURE BACK INTO THE WATER AND TOWARDS THE EQUATOR.
GIVEN THE FORMATIVE STAGE OF THE CYCLONE AND THE MODEL DIVERGENCE AT
THE EXTENDED TAUS, THERE IS LOW CONFIDENCE IN THIS TRACK FORECAST.
THIS WARNING SUPERSEDES AND CANCELS REF A, JOINT TYPHOON WRNCEN PEARL
HARBOR HI 221830Z DEC 12 TROPICAL CYCLONE FORMATION ALERT (WTIO21
PGTW 221830) MAXIMUM SIGNIFICANT WAVE HEIGHT AT 230000Z IS 11 FEET.
NEXT WARNINGS AT 230900Z, 231500Z, 232100Z AND 240300Z.    //
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