000
AXPZ20 KNHC 032153
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED OCT 03 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 
2145 UTC.

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

THE MONSOON TROUGH EXTENDS W ALONG 09.5N ACROSS NW PANAMA AND 
SOUTHERN COSTA RICA TO 09N84W...THEN TURNS NW TO 13N102W...THEN 
DIPS SW TO 10N110W...WIGGLES NW TO 12N119W...THEN SW TO 08N136W
WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH 
CONTINUES SW TO BEYOND 07N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION WITH FREQUENT LIGHTNING IS NOTED FROM 04N TO 
08N BETWEEN 77W AND 89W...FROM 10N TO 15N BETWEEN 93W AND 106W. 
ISOLATED MODERATE TO STRONG CLUSTERS OF CONVECTION IS OBSERVED 
WITHIN 30 NM EITHER SIDE OF A LINE FROM 08N107W TO 07N112W TO 
10N115W TO 08N126W TO 10N130W.

...DISCUSSION...

AN UPPER LEVEL CYCLONE IS CENTERED NEAR 32N135W WITH AN UPPER 
LEVEL TROUGH AXIS EXTENDING S THROUGH ANOTHER SMALL CYCLONE AT 
20N135W TO A BASE OVER THE DEEP TROPICS NEAR 12N134W. AN UPPER 
LEVEL ANTICYCLONE IS POSITIONED NEAR 25N116W WITH A RIDGE 
EXTENDING N BEYOND 32N118W. A SECOND UPPER LEVEL RIDGE EXTENDS 
SW TO A BROAD CREST ALONG 130W FROM 17N TO 22N. ANOTHER UPPER 
CYCLONE IS NOTED NEAR 02N132W AND YET ANOTHER NEAR 07N120W. 
WEAK UPPER DIFFLUENCE IS NOTED OVER THE DEEP TROPICS S AND E OF 
THE UPPER RIDGING SUPPORTING CONVECTION ALONG THE MONSOON TROUGH 
AS PREVIOUSLY DESCRIBED. SOME OF THE RESULTANT DEBRIS MOISTURE 
IS ADVECTED NE ALONG 15N130W BECOMING A NARROW AND GRADUALLY 
THINNING TROPICAL PLUME ALONG THE W PERIPHERY OF THE UPPER 
RIDGE...ROUGHLY THROUGH POINTS 20N128W TO 26N124W TO NEAR 
32N120W. THE REST OF THE DEBRIS MOISTURE SEEMS TO EVAPORATE NEAR 
THE DECAYING CLUSTERS AS THE UPPER LEVELS ARE VERY DRY AIR OVER 
THE REMAINDER OF THE DISCUSSION AREA W OF 110W. 

AN UPPER LEVEL CYCLONE OVER EASTERN ARKANSAS TRAILS AN UPPER 
TROUGH AXIS SW OVER THE NW GULF OF MEXICO REACHING ACROSS 
CENTRAL MEXICO TO OVER THE PACIFIC AT 17N107W THEN CONTINUING S 
ACROSS THE DEEP TROPICS TO TO A BASE AT 01N112W EFFECTIVELY 
SEPARATING THE UPPER FLOW OVER THE DEEP TROPICAL PACIFIC. TO THE 
E OF THIS TROUGH IS AN UPPER LEVEL RIDGE EXTENDING NW FROM 
SOUTH AMERICA...AND IS ADVECTING UPPER MOISTURE S ACROSS THE 
DISCUSSION AREA E OF 100W. THE DEBRIS MOISTURE FROM THE 
PREVIOUSLY MENTIONED CONVECTION...IN THE AREA 10N TO 15N BETWEEN 
93W AND 106W...IS SPREADING NE ACROSS CENTRAL AMERICA BETWEEN 
90W AND 100W...MERGING WITH A PERSISTENT TROPICAL PLUME OVER THE 
SE GULF OF MEXICO.

ELSEWHERE AT THE LOW LEVELS...A BROAD SURFACE RIDGE COVERS THE 
AREA N OF 20N W OF 110W. SOUTHWESTERLY LOW LEVEL WINDS AT 15 TO 
20 KT ALONG WITH CROSS EQUATORIAL SW SWELL CONTINUES TO RESULT 
IN SEAS TO 8 FT IN THE AREA FROM 05N TO 10N BETWEEN 102W AND 
119W. THE WINDS ARE EXPECTED TO DIMINISH TO 15 KT WITHIN 24 
AS THE SW SWELL DECAY TO LESS THAN 8 FT.

GAP WINDS...GALE FORCE WINDS HAVE DIMINISHED TO 30 KT IN AND 
JUST DOWNSTREAM OF THE GULF OF TEHUANTEPEC AND EXPECTED TO 
FURTHER DIMINISH TO 25 KT AFTER THE NORMAL SUNRISE SURGE ON 
THU...BUT EXPECT ANOTHER NEAR SUNRISE SURGE TO 25 KT ON FRI. THE 
INITIAL DRAINAGE SURGE AT 20 TO 25 KT IS EXPECTED TO PROPAGATE W 
ACROSS THE AREA FROM 12N TO 15N BETWEEN 96W AND 106W...WITH SEAS 
OF 8 TO 12 FT...THEN GRADUALLY DECAY BY FRI MORNING. 

IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO...NE TO E WINDS ARE 
FORECAST TO INCREASE TO 20 TO 25 KT LATE TONIGHT AND PERSIST 
THROUGH LATE THU NIGHT BEFORE DIMINISHING.

$$
NELSON