000
AXPZ20 KNHC 070318
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN OCT 07 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURE...

TROPICAL STORM OLIVIA NEAR 14.0N 120.5W 1000 MB AT 07/0300 UTC 
MOVING W OR 280 DEGREES AT 09 KT. MAXIMUM SUSTAINED WIND SPEED IS
45 KT WITH GUSTS TO 55 KT. CURRENTLY SCATTERED MODERATE TO 
STRONG CONVECTION IS OBSERVED WITHIN 150 OVER THE W SEMICIRCLE 
WITH FREQUENT LIGHTNING DETECTED WITHIN A BAND AT 14.5N121W AND 
AT 15N121W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
OBSERVED FROM 180 NM TO 420 NM OUT OVER THE NE QUADRANT. NEW 
BANDS OF CONVECTION ARE CURRENTLY DEVELOPING NEAR THE CENTER. 
OLIVIA WILL MOVE WESTWARD UNDER AN UPPER LEVEL RIDGE IN A 
SOMEWHAT FAVORABLE UPPER LEVEL ENVIRONMENT FOR A COUPLE OF DAYS 
THEN OLIVIA IS FORECAST TO MOVE ACROSS COOLER OCEAN WATERS AND 
EXPERIENCE INCREASING SW SHEAR AND THUS BEGIN TO WEAKEN. FOR 
FURTHER DETAILS SEE AWIPS/WMO HEADERS MIATCMEP5 AND WTPZ25 
KNHC.  

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

THE MONSOON TROUGH EXTENDS W ACROSS THE SOUTHERN CARIBBEAN ALONG 
11N FROM EXTREME N COLOMBIA TO ACROSS THE NORTHERN COSTA RICA TO 
11N99W TO 09N105W TO 10N109W...THEN RESUMES SW OF TS OLIVIA AT 
12N122W TO 08N128W TO 10N137W WHERE LOW LEVEL WINDS INDICATE A 
TRANSITION TO AN ITCZ WHICH CONTINUES W TO BEYOND 09N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION OBSERVED WITHIN 90 
NM EITHER SIDE OF A LINE FROM 08N78W TO 07N83W TO 09N88W TO 
07N95W. ISOLATED MODERATE AND STRONG CONVECTION IS NOTED FROM 
07N TO 11N BETWEEN 95W AND 108W...AND ALSO WITHIN 30 NM EITHER 
SIDE OF A LINE FROM 10N121W TO 06N128W TO 09N133W.

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS POSITIONED N OF TROPICAL STORM 
OLIVIA AT 17N117W WITH UPPER RIDGES EXTENDING N BEYOND 
32N116W...SE TO A CREST AT 11N104W AND W TO A CREST AT 15N135W. 
AN UPPER 50-90 KT JET IS DETECTED BY CLOUD MOTION VECTORS ALONG 
THE NW PERIPHERY OF THE ANTICYCLONE THROUGH POINTS 23N140W TO 
32N123W TO 33N114W AND ADVECTING A 120 NM WIDE PLUME OF UPPER 
MOISTURE NE AND E ACROSS THE NORTHERN RIDGE CREST AND ACROSS THE 
SW AND S-CENTRAL CONUS. THE DEBRIS MOISTURE FROM OLIVIA IS 
ADVECTED NE TO 22N111W WHERE IT TURNS E AND NOW MOVING ACROSS 
THE W-CENTRAL MEXICAN COAST.

AN UPPER SHORTWAVE TROUGH OVER THE CENTRAL CONUS EXTENDS SW 
ACROSS THE WESTERN GULF OF MEXICO AND OVER CENTRAL MEXICO 
THROUGH A SMALL UPPER CYCLONE AT 19N97W...WITH THE TROUGH 
BECOMING INVERTED OVER THE DEEP TROPICAL PACIFIC BETWEEN 
100W-102W. THIS TROUGH CONTINUES TO SPLIT THE UPPER FLOW OVER 
THE TROPICAL PACIFIC. AN UPPER ANTICYCLONE OVER THE EASTERN GULF 
OF HONDURAS HAS ITS ANTICYCLONIC ENVELOPE EXTENDING S OVER THE 
DISCUSSION AREA TO THE N OF 05N AND E OF 94W. THE ASSOCIATED 
UPPER DIFFLUENCE IS SUPPORTING THE CONVECTION ALONG THE EASTERN 
SEGMENT OF THE LOWER LEVEL MONSOON TROUGH AS PREVIOUSLY 
DESCRIBED. DENSE DEBRIS MOISTURE IS OBSERVED OVER THE AREA N OF 
05W E OF 90W.

ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE IS NEAR 
30N133W WITH RIDGING COVERING THE DISCUSSION AREA N OF 20N W OF 
THE BAJA PENINSULA. NW WINDS AT 20-25 KT ARE REPORTED OVER THE 
AREA N OF 27N E OF 118W TO THE NORTHERN BAJA CALIFORNIA 
PENINSULA...WITH LITTLE CHANGE EXPECTED THROUGH TUE...THEN THE 
GRADIENT WILL RELAX SUPPORTING NW 10-15 KT AND SEAS 3-5 FT ALONG 
THE ENTIRE WESTERN COAST OF THE BAJA PENINSULA THROUGH MID WEEK. 
GUIDANCE SUGGESTS SEAS WILL INCREASE TO 6 FT IN BUILDING NW 
SWELL OVER THE AREA N OF 28N LATE THU...WITH THE GRADIENT 
INCREASING THE NW FLOW TO 20-25 KT FRI NIGHT ALONG THE W COAST 
OF BAJA TO THE N OF 24N.

GAP WINDS...NORTHERLY WINDS AT 20-25 KT ARE EXPECTED TO PULSE 
ACROSS THE GULF OF TEHUANTEPEC BEGINNING LATE TONIGHT AND 
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK...INCREASING TO 20-30 
KT ON THU. THE STRONGEST DRAINAGE FLOW WILL OCCUR LATE EACH 
NIGHT THROUGH A COUPLE OF HOURS AFTER SUNRISE EACH MORNING.  
 
$$
NELSON