Wednesday, June 11, 2014

Cyclone NANAUK takes shape, intensifies, moves N-W

An insight into 02A - Nanauk - "Will it hit Indian coast??"

Analysis at 1:30pm suggests that, Cyclone Nanauk has further intensified and has tracked N-W during past 12hrs.
Present position is 16.97N , 66.57E
Pressure around 980mb
Winds upto 110kmph.

1:30pm, Visible shot reveals an EYE in Cyclone Nanauk. And heavy convective activity is concentrated along its S-W quadrant.

JTWC report at 2pm
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TROPICAL CYCLONE (TC) 02A (TWO), LOCATED APPROXIMATELY 496 NM EAST-
SOUTHEAST OF MASIRAH ISLAND, HAS TRACKED WEST-NORTHWESTWARD AT 05
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY INDICATES THAT DEEP CONVECTION HAS WEAKENED OVER THE PAST 
SIX HOURS DUE TO INCREASING EASTERLY VERTICAL WIND SHEAR (VALUES 
ABOUT 20 TO 25 KNOTS). A 110549Z METOP-A IMAGE DEPICTS CURVED DEEP 
CONVECTIVE BANDING WRAPPING INTO A DEFINED CENTER, HOWEVER, THE BULK 
OF THE DEEP CONVECTION IS DISPLACED OVER THE WESTERN SEMI-CIRCLE. 
BASED ON THE DEGRADED MICROWAVE SIGNATURE, THERE IS FAIR CONFIDENCE 
IN THE INITIAL POSITION. FURTHERMORE, DVORAK INTENSITY ESTIMATES 
HAVE REMAINED AT 55 KNOTS, THEREFORE, THE INITIAL INTENSITY IS 
MAINTAINED AT 55 KNOTS. OVERALL, THERE ARE NO MAJOR CHANGES TO THE 
FORECAST PHILOSOPHY WITH TC 02A EXPECTED TO MAINTAIN A WEST-
NORTHWESTWARD TRACK UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL 
STEERING RIDGE. DYNAMIC GUIDANCE HAS DEGRADED WITH POOR AGREEMENT 
DUE TO MAJOR DIFFERENCES IN THE INTENSITY AND TRACK FORECASTS. GFDN 
INDICATES RAPID WEAKENING AND AN ERRATIC NORTHWARD TRACK WHICH MAKES 
LITTLE SENSE WHILE UKMO TRACKS THE SYSTEM SLOWLY INTO THE 
SUBTROPICAL RIDGE. GFS AND NAVGEM HAVE REMAINED THE MOST CONSISTENT 
MODELS AND PRESENT THE MOST LOGICAL SOLUTION WITH A WEST-
NORTHWESTWARD TRACK. THE JTWC FORECAST FAVORS THESE MODELS AND IS 
CONSISTENT WITH THE PREVIOUS FORECASTS. THE INTENSITY FORECAST 
REMAINS THE MOST CHALLENGING ISSUE WITH GFS TRACKING A STRONGER 
SYSTEM WESTWARD OVER OMAN WHILE NAVGEM WEAKENS THE SYSTEM PRIOR TO 
LANDFALL AND TURNS IT WEST-SOUTHWESTWARD. DUE TO THE PRESENCE OF DRY 
AIR AND PERSISTENT EASTERLY VERTICAL WIND SHEAR, THE SYSTEM WILL 
LIKELY WEAKEN RAPIDLY AS IT APPROACHES THE COAST. THIS FORECAST WILL 
MAINTAIN THE PEAK INTENSITY OF 80 KNOTS FOR THE TIME BEING. DUE TO 
THE INCREASING DISAGREEMENT BETWEEN THE MODELS AND THE UNCERTAINTY 
IN THE INTENSITY FORECAST, THERE IS LOW CONFIDENCE IN THE JTWC 
FORECAST TRACK, ESPECIALLY AFTER TAU 72.

Forecast::
~~~~~~~~~~~~~~~~
NAVGEM model expects the Cyclone to track N-W and reach Oman coast on 15/16-Jun as Cyclone itself.

GFS expects the Cyclone to track N-W during next 72hrs and weaken or even dissipate before reaching Oman coast on 15-Jun.
If this happens, then it's good for the Arabian sea wing of the Monsoon to consolidate and progress North upto Mumbai.

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