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000
AXPZ20 KNHC 170253
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL TROPICAL STORM CENTER MIAMI FL
0405 UTC WED SEP 17 2014

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0245 UTC.

...SPECIAL FEATURES...

TROPICAL STORM POLO LOCATED NEAR 13.8N 101.3W OR ABOUT 235
MILES SSW OF ACAPULCO MEXICO AND ABOUT 270 MILES S OF
ZIHUATANEJO MEXICO AT 0300 UTC SEP 17. THE MINIMUM CENTRAL
PRESSURE IS ESTIMATED AT 1000 MB. POLO IS MOVING NW OR 310 DEG
AT 10 KT...AND THIS MOTION IS EXPECTED TO CONTINUE WITH POLO
TRACKING PARALLEL TO THE SW COAST OF MEXICO FOR THE NEXT COUPLE
OF DAYS. MAXIMUM SUSTAINED WINDS ARE CURRENTLY AT 45 KT WITH
GUSTS 55 KT...AND POLO IS EXPECTED TO INTENSIFY TO A HURRICANE
ON WED NIGHT. CURRENTLY SCATTERED MODERATE TO STRONG CONVECTION
IS OBSERVED WITHIN 150 NM OVER THE SE QUADRANT AND ELSEWHERE
WITHIN 150 NM EITHER SIDE OF A LINE FROM 17N100W TO 14N102W.
CONVECTION OVER THE E SEMICIRCLE REACHES THE COAST OF MEXICO
BETWEEN 97W AND 105W...AND MAY RESULT IN HEAVY RAINFALL WITH THE
POTENTIAL AGAIN FOR FLASH FLOODS AND MUDSLIDES IN AREAS ALREADY
AFFECTED BY NORBERT AND ODILE. SEE THE LATEST PUBLIC ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPEP2/WTPZ32 KNHC AND FORECAST/
ADVISORY UNDER HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS.

TROPICAL STORM ODILE LOCATED NEAR 29.7N 113.6W AT 0300 UTC SEP
17 OR ABOUT 110 MILES S OF PUERTO PENASCO MEXICO. THE MINIMUM
CENTRAL PRESSURE IS 994 MB. ODILE IS MOVING N OR 360 DEG AT 06
KT...AND ODILE SHOULD TURN MORE N-NE AND SLOW DOWN LATE TONIGHT
INTO WED. MAXIMUM SUSTAINED WINDS 45 KT GUSTS 55 KT AND ODILE
SHOULD MAINTAIN THIS STRENGTH WHILE TRACKING ACROSS THE GULF OF
CALIFORNIA WATERS...THEN OF COURSE RAPID WEAKEN AS THE CYCLONE
MOVES INLAND OVER NW MEXICO LATE WED. CURRENTLY SCATTERED
MODERATE ISOLATED STRONG CONVECTION IS OBSERVED OVER THE GULF OF
CALIFORNIA TO THE N OF 28N. RAINFALL AMOUNTS OF 6 TO 12 INCHES
ARE EXPECTED WITH ISOLATED MAXIMUM RAINFALL OF 18 INCHES AROUND
PORTIONS OF THE BAJA PENINSULA AND NW MEXICO OVER THE NEXT 2
DAYS. THESE RAINS COULD RESULT IN LIFE-THREATENING FLASH FLOODS
AND MUD SLIDES...ESPECIALLY IN MOUNTAINOUS AREAS. LARGE SWELLS
FROM ODILE WILL AFFECT PORTIONS OF THE SW COAST OF MEXICO DURING
THE NEXT COUPLE OF DAYS...AND WILL CONTINUE TO AFFECT PORTIONS
OF THE BAJA CALIFORNIA PENINSULA AND THE GULF OF CALIFORNIA.
THESE SWELLS WILL LIKELY CAUSE LIFE-THREATENING SURF AND RIP
CURRENT CONDITIONS. SEE LATEST INTERMEDIATE PUBLIC ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPEP5/WTPZ35 KNHC AND
FORECAST/ADVISORY UNDER HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE
DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS W ACROSS THE EXTREME SW CARIBBEAN
CROSSING THE BORDER OF PANAMA AND COSTA RICA TO THE COAST AT
09N82W...THEN TURNS NW TO 12N92W WHERE IT LOSES IDENTITY IN THE
BROAD CIRCULATION ASSOCIATED WITH TROPICAL CYCLONE POLO. THE
MONSOON TROUGH RESUMES W OF POLO NEAR 14N104W AND CONTINUES SW
TO 10N125W...THEN TURNS NW TO AN EMBEDDED 1010 MB LOW AT
12N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
OBSERVED WITHIN 240 NM OF THE COAST OF CENTRAL AMERICA FROM 86W
TO 90W...AND WITHIN 240 NM EITHER SIDE OF A LINE FROM 09N103W TO
12N110W AND WITHIN 90 NM EITHER SIDE OF A LINE FROM 12N112W TO
12N120W.

...DISCUSSION...
A 1016 MB SURFACE HIGH IS CENTERED NEAR 24N130W WITH A RIDGE
EXTENDING SE TO 14N120W. A RIDGE ALSO EXTENDS SW TO BEYOND
21N140W. THE RIDGE IS MAINTAINING GENTLE TO MODERATE TRADES
ACROSS THE TROPICS W OF 120W AND TO THE N OF THE MONSOON TROUGH.

A WEAKENING COLD FRONT EXTENDS FROM 32N134W TO 25N140W.
SOUTHERLY FLOW IS AT 20-25 KT TO THE N OF 29N WITHIN 240 NM E OF
FRONT WITH SEAS OF 7-10 FT. MIXED NW AND S SWELL IS MAINTAINING
SEAS OF 8-9 FT ELSEWHERE W OF A LINE FROM 30N130W TO 25N140W.
THE FRONT WILL WEAKEN TO TROUGH FROM 30N131W TO 24N140W LATE WED
AND FROM 27N130W TO 24N140W ON THU WITH SEAS EXPECTED TO SUBSIDE
BELOW 8 FT ON THU AFTERNOON.

LARGE CROSS-EQUATORIAL SW SWELL HAS REACHED THE COAST OF MEXICO
AND CENTRAL AMERICA WITH SEAS TO 8 FT OR MORE ACROSS MOST OF THE
FORECAST AREA E OF 110W. SEAS WILL GRADUALLY SUBSIDE IN THE
EASTERN PACIFIC EXCEPT IN THE IMMEDIATE VICINITY OF POLO ON
THU AS THE CROSS-EQUATORIAL SWELL DAMPENS.

$$
NELSON

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