000
AXPZ20 KNHC 120950
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE OCT 12 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE EXTENDS FROM 08N78W TO 1011 
MB LOW PRES NEAR 10N122W TO 08N140. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS NOTED N OF 03N E OF 80W AND ALSO WITHIN 60 
NM LINE FROM 14N119W TO 08N128W.

...DISCUSSION...

AN UPPER TROUGH IS NEARLY STATIONARY ALONG 31N97W TO 30N110W 
INTO AN UPPER CYCLONE AT 26N121W TO ANOTHER UPPER CYCLONE AT 
26N132W...WITH THE TROUGH CONTINUING SW TO BEYOND 22N140W. 
JUST TO THE N IS AN UPPER ANTICYCLONE AT 31N128W WITH AN UPPER 
RIDGE EXTENDING SW TO 30N132W. UPPER MOISTURE IS NOTED N OF 28N 
BETWEEN 116W AND 136W WITH THE PLUME CONTINUING NE ACROSS 
SOUTHERN CALIFORNIA. THE UPPER LEVELS APPEAR DRY WITHIN 120 NM 
OF THE UPPER TROUGH AND EMBEDDED CYCLONES.

A NEGATIVE TILT UPPER TROUGH EXTENDS SE FROM THE PREVIOUSLY 
MENTIONED UPPER CYCLONE AT 26N121W TO A BASE 09N108W. THIS 
TROUGH EFFECTIVELY SEPARATES THE UPPER FLOW OVER THE TROPICAL 
PACIFIC. A BROAD UPPER RIDGE CRESTS ALONG 20N140W TO 24N123W TO 
13N110W. THE ASSOCIATED UPPER DIFFLUENCE IS ENHANCING CONVECTION 
ALONG THE ITCZ AXIS BETWEEN 113W AND 127W WITH THE DEBRIS 
MOISTURE FROM THIS CONVECTION...AND UPPER DEBRIS MOISTURE 
STREAMING IN FROM CONVECTION W OF THE DISCUSSION AREA... 
COMBINING TO MAKE THE UPPER LEVELS MOIST UNDER THE RIDGE TO THE 
N OF THE ITCZ. FURTHER E...AN UPPER ANTICYCLONE NEAR JAMAICA HAS 
A RIDGE EXTENDING WSW ACROSS CENTRAL AMERICA TO A CREST OVER THE 
TROPICAL PACIFIC AT 10N104W. ALTHOUGH THE ASSOCIATED UPPER 
DIFFLUENCE IS ENHANCING SIGNIFICANT CONVECTION ASSOCIATED WITH 
TROPICAL STORM PAULA IN THE GULF OF HONDURAS...ONLY A FEW SMALL 
CONVECTIVE CLUSTERS ARE NOTED WITHIN THE DISCUSSION AREA ALONG 
THE PACIFIC COAST OF COLOMBIA AND PANAMA. THE RESULTANT DEBRIS 
MOISTURE IS NOTED N OF 07N E OF 90W. OTHERWISE...THE UPPER 
LEVELS ARE VERY DRY E OF 111W.

ELSEWHERE AT THE LOW LEVELS...A SURFACE HIGH PRES IS NEAR 
24N120W WITH A RIDGE SE TO NEAR 16N107W. THE GRADIENT SW OF THIS 
SURFACE RIDGE...AND N OF THE ITCZ...IS SUPPORTING NE TRADES AT 
20 KT WITH SEAS TO 11 FT OVER THE WATERS FROM 12N TO 18N W OF 
120W. THE SURFACE LOW EMBEDDED IN THE ITCZ NEAR 10N122W HAS A 
TROUGH EXTENDING TO NEAR 14N117W. THIS LOW IS EXPECTED TO MOVE 
TO NEAR 12N127W TONIGHT AND NEAR 13N130W WED NIGHT WITH THE 
TROUGH CONTAINING NE TO NEAR 18N126W WED NIGHT. NE FLOW AT 15 TO 
20 KT IS EXPECTED TO CONTINUE W OF THE THE LOW AND TROUGH.

GAP WINDS...NORTHERLY WINDS ARE EXPECTED TO INCREASE TO 20 TO 25 
KT TONIGHT OVER AND JUST DOWNSTREAM OF THE GULF OF TEHUANTEPEC. 
EXPECTING THESE WINDS TO FURTHER INCREASE TO MINIMAL GALE AROUND 
SUNRISE WED...STRENGTHEN TO 30 TO 40 KT WED NIGHT AND CONTINUE 
THROUGH AT LEAST FRI MORNING. 
 
$$
NELSON