Tropical Storm KHANUN Advisory Mon Jul 16

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT)
WARNING NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 08W, LOCATED APPROXIMATELY 575 NM EAST-
SOUTHEAST OF KADENA AB, OKINAWA, HAS TRACKED WEST-NORTHWESTWARD AT
13 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON A
152332Z PGTW SATELLITE FIX AS WELL AS 152322Z SSMIS AND 152114Z
CORIOLIS MICROWAVE SATELLITE IMAGES. THE CURRENT INTENSITY IS BASED
ON A DVORAK SATELLITE INTENSITY ESTIMATE OF 30 KNOTS FROM PGTW. TD
08W HAS BECOME A BIT MORE ORGANIZED OVER THE PAST 06 HOURS, WITH
DEEP CONVECTION DEVELOPING OVER AN INCREASINGLY SYMMETRIC LOW-LEVEL
CIRCULATION CENTER. TD 08W REMAINS SITUATED IN AN AREA OF LOW
VERTICAL WIND SHEAR BENEATH A NARROW UPPER-LEVEL RIDGE AXIS.
TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELLS TO THE WEST AND
SOUTHEAST ARE ENHANCING OUTFLOW ALOFT. ADDITIONALLY, RECENT ANIMATED
WATER VAPOR IMAGERY INDICATES AN INCREASE IN POLEWARD OUTFLOW INTO
THE MIDLATITUDE WESTERLIES OVER THE PAST SEVERAL HOURS. HOWEVER, THE
OUTFLOW CONNECTION TO THE TUTT CELL TO THE SOUTHEAST APPEARS TO BE
DISSIPATING AS AN UPPER-LEVEL RIDGE BUILDS TOWARD TD 08W FROM THE
EAST.
3. FORECAST REASONING.
   A. THE FORECAST TRACK WAS SHIFTED EQUATORWARD AND SLOWED DOWN
SLIGHTLY IN THE TAU 00 TO TAU 24 FORECAST PERIOD BASED ON MORE
WESTWARD AND SLOWER THAN EXPECTED STORM MOTION OBSERVED OVER THE
PAST 06 HOURS.
   B. TD 08W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP
LAYER SUBTROPICAL RIDGE POSITIONED EAST OF HONSHU. THE SYSTEM IS
EXPECTED TO TRACK GENERALLY NORTHWESTWARD ALONG THE PERIPHERY OF THE
STEERING RIDGE OVER THE NEXT 30 HOURS BEFORE TURNING POLEWARD AHEAD
OF A NEARLY STATIONARY MIDLATITUDE TROUGH OVER THE YELLOW SEA. TD
08W WILL INTENSIFY SLOWLY OVER THE NEXT 24 HOURS AS THE LLCC
CONTINUES TO CONSOLIDATE AND OUTFLOW TOWARD THE TUTT CELL TO THE
SOUTHEAST DECREASES. AFTER TAU 24, TD 08W WILL ROUND THE STEERING
RIDGE AXIS AND ACCELERATE POLEWARD AHEAD OF THE MIDLATITUDE TROUGH.
PASSAGE OVER COOLER WATER AND CONVERGENCE ALOFT WILL HALT THE
INTENSIFICATION TREND AND INDUCE STEADY WEAKENING BY TAU 48. THE
CURRENT FORECAST IS IN GOOD AGREEMENT WITH A TIGHTLY-GROUPED
NUMERICAL MODEL FORECAST PACKAGE. GIVEN THE STRAIGHTFORWARD SYNOPTIC
PATTERN AND GOOD MODEL AGREEMENT, THERE IS HIGH CONFIDENCE IN THE
FORECAST TRACK.//
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