Subject: Pacific-NW: Subj/significant Tropical Weather Advisory For The Western And

From: SIU Weather Processor <[email-masked]>
Date: Thu, 21 Oct 2010 00:56:07 -0500

ABPW10 PGTW 210600
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/210600Z-220600ZOCT2010//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/210151ZOCT2010//
REF/B/MSG/NAVMARFCSTCEN PEARL HARBOR HI/210251ZOCT2010//
REF/C/MSG/NAVMARFCSTCEN PEARL HABROR HI/200921ZOCT2010//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REFS B AND C ARE
/TROPICAL CYCLONE FORMATION ALERTS.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 210000Z, TYPHOON 15W (MEGI) WAS LOCATED NEAR 19.4N
117.4E, APPROXIMATELY 250 NM SOUTHEAST OF HONG KONG, AND HAD TRACKED
NORTHWARD AT 06 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED
SURFACE WINDS WERE ESTIMATED AT 100 KNOTS GUSTING TO 125 KNOTS. SEE
REF A (WTPN31 PGTW 210300) FOR FURTHER DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 18.4N
160.6E, IS NOW LOCATED NEAR 19.2N 159.9E, APPROXIMATELY 380 NM WEST
OF WAKE ISLAND. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS
IMPROVED CONVECTIVE BANDING OVER THE NORTHWEST QUADRANT WITH A
SMALL, WELL-DEFINED, PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER
(LLCC). A 202258Z METOP-A IMAGE DEPICTS CONVECTIVE BANDING WRAPPING
FROM THE NORTHEAST INTO THE WEST QUADRANT. TOTAL PRECIPITABLE WATER
(TPW) PRODUCTS SUGGEST THAT THE SYSTEM MAY BE TRANSITIONING FROM A
COLD-CORE TO A WARM-CORE SYSTEM WITH THE LLCC EMBEDDED WITHIN
A POCKET OF INCREASING, MORE FAVORABLE TPW VALUES. UPPER-LEVEL
ANALYSIS INDICATES AN IMPROVING ENVIRONMENT. THE LLCC IS DEVELOPING
UNDER A TUTT CELL, HOWEVER, DEEP CONVECTION HAS BECOME MORE
ORGANIZED NEAR THE CENTER OVER THE PAST 6 HOURS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 20 TO 24 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO GOOD. SEE REF B (WTPN22 PGTW 210300) FOR
FURTHER DETAILS.
      (2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 16.3N
146.7E, IS NOW LOCATED NEAR 17.0N 142.6E, APPROXIMATELY 255 NM NORTH-
NORTHWEST OF ANDERSEN AFB, GUAM. ANIMATED MULTISPECTRAL IMAGERY
SHOWS SUSTAINEDCONVECTION ASSOCIATED WITH A DEVELOPING LLCC
APPROXIMATELY 80 NM NORTHEAST OF SAIPAN. OBSERVATIONS FROM
SAIPAN INDICATE A 4 MB DROP IN SEA LEVEL PRESSURE OVER THE LAST 24
HOURS. ALSO, A 200346Z AMSR-E MICROWAVE IMAGE SHOWS FORMATIVE CURVED
BANDING INTO THE LLCC. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS
TO THE WEST OF A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL THAT
IS PROVIDING EQUATORWARD OUTFLOW. HOWEVER, AN ANTICYCLONE TO THE
NORTH IS SUPPRESSING THE POLEWARD OUTFLOW CHANNEL. THE CYCLONE IS
CURRENTLY IN AN AREA OF LOW VERTICAL WIND SHEAR AND IS EXPECTED TO
CONTINUE MOVING WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF
THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE TO THE NORTH. NUMERIC MODELS
INDICATE A GRADUAL DEVELOPMENT AS POLEWARD OUTFLOW IMPROVES WITH THE
SYSTEM'S REORIENTATION TO THE TUTT CELLS IN THE AREA. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. IN VIEW OF THE
IMPROVING ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS GOOD.
SEE REF C (WTPN21 PGTW 200930) FOR FURTHER DETAILS.
      (3) NO OTHER SUSPECT AREAS.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.//

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