000
AXPZ20 KNHC 110949
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON OCT 11 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 MEANDERS OVER THE PACIFIC 
WATERS FROM 08N TO 10N BETWEEN 82W AND 140W. INTERMITTENT 
CYCLONIC SWIRLS ARE NOTED WITH THE ZONE. CONVECTION IS 
SUPPRESSED ALONG THE AXIS WITH ONLY SCATTERED MODERATE ISOLATED 
STRONG CURRENTLY NOTED WITHIN 60 NM OF 06.5N78W AND 07N82W...
AND WITHIN 30 NM OF 08N110W AND 10N117W AND 09N122W.

...DISCUSSION...

AN UPPER TROUGH IS NEARLY STATIONARY ALONG 32N102W TO 27N119W TO 
23N1113W TO 23N140W AND INTO AN UPPER CYCLONE W OF THE AREA NEAR 
18N149W. THIS TROUGH IS EXPECTED TO SHIFT NORTHWARD OVER THE 
NEXT FEW DAYS AND A TROPICAL RIDGE TO THE S AMPLIFIES N. ANS 
THE TROUGH SHIFTS N SEVERAL CUT OFF CYCLONES ARE LIKELY TO 
DEVELOP ALONG 31N NEAR 138W AND NEAR 120W. AN UPPER ANTICYCLONE 
IS CENTERED AT 32N127W WITH A RIDGE EXTENDING SW TO 30N140W AND 
A RIDGE ALSO EXTENDS NE ACROSS SOUTHERN CALIFORNIA. UPPER 
MOISTURE IS NOTED N OF 29N WITHIN THE RIDGE.

AN EMBEDDED UPPER CYCLONE IS NOTED NEAR 25N123W WITH A NEGATIVE 
TILT UPPER TROUGH EXTENDS SE TO A BASE AT 13N116W EFFECTIVELY 
SEPARATING THE UPPER FLOW OVER THE TROPICAL PACIFIC. AN
UPPER ANTICYCLONE IS NOTED NEAR 10N125W WITH BROAD ANTICYCLONIC 
FLOW DOMINATING THE AREA S OF 21N BETWEEN 143W AND 120W. THE 
ASSOCIATED UPPER DIFFLUENCE ENHANCED CONVECTION EARLIER ALONG 
THE ITCZ AXIS 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 FROM 08N TO 21N BETWEEN 120W AND 144W. FURTHER E...
AN UPPER ANTICYCLONE NEAR PUERTO RICO HAS A RIDGE EXTENDING W 
ACROSS CENTRAL AMERICA ALONG 15N TO A CREST OVER THE TROPICAL 
PACIFIC AT 13N110W. ALTHOUGH THE ASSOCIATED UPPER DIFFLUENCE IS 
ENHANCING SIGNIFICANT CONVECTION OVER COLOMBIA AND OVER THE W 
CARIBBEAN...ONLY A FEW CONVECTIVE CLUSTERS ARE NOTED WITHIN THE 
DISCUSSION AREA ALONG THE PACIFIC COAST OF COLOMBIA...PANAMA AND 
COSTA RICA. THE RESULTANT DEBRIS MOISTURE IS NOTED N OF 04N E OF 
86W. OTHERWISE...THE UPPER LEVELS ARE VERY DRY N OF 23N AND S OF 
23N E OF 113W.

ELSEWHERE AT THE LOW LEVELS...A BROAD FRONTAL TROUGH EXTENDS 
FROM 33N130W TO 30N145W WITH A RIDGE BRIDGING ACROSS THE FRONT 
FROM 34N138W TO NEAR 17N113W. THE GRADIENT SW OF THIS SURFACE 
RIDGE...AND N OF THE ITCZ...IS SUPPORTING NE TRADES AT 20 KT 
WITH SEAS TO ABOUT 11 FT IN ASSOCIATED NE SWELL NOW MIXING WITH 
SOME NW SWELL THAT ACCOMPANIED THE DISSIPATING FRONT. THE PARENT 
SURFACE HIGH IS EXPECTED TO SHIFT SE TO NEAR 27N122W TUE AND WED 
AS STRONGER HIGH PRESSURE BUILDS SW ACROSS THE AREA W OF 125W.

GAP WINDS...NORTHERLY WINDS AT 10 TO 15 KT ARE NOTED OVER AND 
JUST DOWNSTREAM OF THE GULF OF TEHUANTEPEC. EXPECT THESE WINDS 
TO FURTHER DIMINISH TO 5 TO 10 KT TUE. HIGH PRES WILL BUILD OVER 
THE GULF OF MEXICO TUE NIGHT WITH NORTHERLY WINDS INCREASING TO 
20 TO 25 KT IN THE GULF OF TEHUANTEPEC AND FURTHER INCREASING TO 
25 TO 30 KT AROUND SUNRISE WED. EXPECT MINIMAL GALE CONDITIONS 
LATE WED NIGHT AND THU. 
 
$$
NELSON