000
AXPZ20 KNHC 182209
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON JUN 18 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2030 UTC.

...SPECIAL FEATURES...
SHOWERS AND THUNDERSTORMS CONTINUE TO FLARE IN SHORT LINES AND 
BANDS ACROSS THE SOUTH AND EAST SEMICIRCLES OF AN AREA OF LOW 
PRESSURE LOCATED NEAR 17N108.5W...WHICH IS DRIFTING SLOWLY E. 
SOME REMNANT MOISTURE FROM THE REMAINS OF CARLOTTA ALSO APPEAR 
TO BE WRAPPING AROUND THE NORTHERN PERIPHERY OF THIS 
CIRCULATION. THIS LOW REMAINS EMBEDDED WITHIN THE NE END OF THE 
EPAC MONSOON TROUGH...WITH A BROAD ZONE OF SW WINDS 20 TO 25 KT 
PREVAILING S OF THE LOW AND THE TROUGH E OF 112W. ENVIRONMENTAL 
CONDITIONS ARE FAVORABLE FOR ADDITIONAL DEVELOPMENT OF THIS 
SYSTEM...AND IT COULD BECOME A TROPICAL DEPRESSION DURING THE 
NEXT DAY OR SO AS IT MOVES SLOWLY EASTWARD.  THIS SYSTEM HAS A 
HIGH CHANCE...60 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING 
THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...PERIODS OF HEAVY 
RAINFALL AND THE THREAT FOR FLASH FLOODS AND MUDSLIDES WILL 
CONTINUE ACROSS COASTAL PORTIONS OF SOUTHWESTERN AND 
SOUTH-CENTRAL MEXICO... GENERALLY FROM NEAR ACAPULCO TO PUERTO 
VALLARTA...FOR THE NEXT COUPLE OF DAYS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM LOW PRES 1009 MB OVER SW CARIBBEAN 
NEAR 16.5N83W THEN MEANDERS W AND NW ACROSS CENTRAL AMERICA AND 
S COASTAL PORTIONS OF SE MEXICO TO NEAR 18N101W...WHERE IT 
REMAINS FRACTURED FROM THE FORMER CARLOTTA...THEN RESUMES AGAIN 
FROM LOW PRES 1006 MB NEAR 17N108.5W TO SECOND LOW PRES 1009 MB 
NEAR 13.5N118W TO BEYOND 03N140W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITHIN 120 NM S OF TROUGH BETWEEN 88W AND 99W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 210 
NM S AND SE OF TROUGH FROM 108W TO 135W.

...DISCUSSION...
ALOFT...A MIDDLE TO UPPER LEVEL CUT OFF LOW IS NEAR 25N133W AND 
SHIFTING W. A SURFACE LOW UNDERNEATH THIS CIRCULATION YESTERDAY 
HAS WEAKENED TO AN INVERTED TROUGH FROM 30N126W TO 21N135W. 
UPPER RIDGING GENERALLY PREVAIL E OF THIS LOW...BETWEEN 100W AND 
128W...CENTERED ON A PRIMARY UPPER ANTICYCLONE NEAR 23N113W. THE 
RIDGE EXTENDS SW...GENERALLY ALONG THE MONSOON TROUGH 
AXIS...WHERE DEEP CONVECTION IS AIDING IN MAINTAINING UPPER 
DIVERGENCE. THE RIDGE ALSO EXTENDS SE ALONG THE SW MEXICAN 
COAST AND CENTRAL AMERICA...TO THE SW CARIBBEAN. 

AT THE SURFACE...A HIGH PRES RIDGE CENTERED ON A MEAN 1034 MB 
HIGH NEAR 40N150W EXTENDS E TO THE COAST OF N CALIFORNIA. A VERY 
TIGHT PRES GRADIENT CONTINUES BETWEEN THE SURFACE TROUGH 
MENTIONED ABOVE...AND THIS HIGH...YIELDING STRONG NELY WINDS 
ACROSS NW PORTIONS OF THE DISCUSSION AREA...WITH A 1548 UTC 
WINDSAT PASS SUGGESTING WINDS TO 30 KT N OF 28N ACROSS THIS 
AREA. RECENT ALTIMETER PASSES ALSO MEASURED AN ELONGATED AREA OF 
12-14 FT SEAS THERE. GLOBAL MODELS INDICATE THAT THE TROUGH WILL 
DRIFT WWD WHILE THE HIGH PRES WILL WEAKEN WEAKEN AND SHIFT 
SW...RESULTING IN A GRADUAL DECREASE IN WINDS AND SEAS ACROSS 
THE NW WATERS OVER THE NEXT COUPLE OF DAYS.

AS MENTIONED ABOVE...SW WINDS OF 20-25 KT ARE NOTED IN A LARGE 
AREA SE OF LOW PRES CENTER NEAR 17N108.5W...AND ALONG AND SE OF 
THE MONSOON TROUGH THERE...COVERING ROUGHLY FROM 12N TO 17N 
BETWEEN 110W AND 118W. THE SW FLOW EXTENDS FARTHER E AND BECOMES 
WLY ALONG THE PACIFIC COAST OF MEXICO TO OFFSHORE OF THE GULF OF 
TEHUANTEPEC. THIS FLOW IS BRINGING ABUNDANT TROPICAL MOISTURE 
ACROSS THESE AREAS...PROVIDING THE POTENTIAL FOR PERIODS OF 
LOCALLY HEAVY RAIN AND THE THREAT FOR FLASH FLOODS AND 
MUDSLIDES...PARTICULARLY OVER MOUNTAINOUS AND STEEP TERRAIN. 
THIS PATTERN IS EXPECTED TO REMAIN IN PLACE FOR THE NEXT FEW 
DAYS AND WILL MAINTAIN A WET WEATHER PATTERN ACROSS CENTRAL 
AMERICA AND SOUTHERN MEXICO.


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STRIPLING