000
AXPZ20 KNHC 280947
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI OCT 28 2011

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 09.5N84W TO 08N100W TO 11N118W. THE 
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N118W TO 
13N130W TO 13N138W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 03N TO 07N E OF 79W AND FROM 10N TO 12N E OF 
88W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 11N TO 16N 
BETWEEN 120W AND 131W.

...DISCUSSION...

AN ELONGATED UPPER LEVEL CYCLONE HAS CUT OFF CENTERED NEAR 
28N135W WITH AN UPPER LEVEL TROUGH EXTENDING FROM 32N133W 
THROUGH THE CYCLONE TO A BASE OVER THE DEEP TROPICAL PACIFIC AT 
10N130W. AN UPPER LEVEL ANTICYCLONE IS OVER THE E PACIFIC NEAR 
17N116W WITH AN UPPER RIDGE EXTENDING NW TO A CREST AT 32N123W 
AND ALSO NE-E FROM THE ANTICYCLONE TO OVER W CENTRAL MEXICO AT 
22N103W. UPPER LEVEL DIFFLUENCE E OF THE UPPER TROUGH AXIS IS 
ENHANCING CONVECTION ALONG THE ITCZ AND THE WESTERN EXTENT OF
THE MONSOON TROUGH AS DESCRIBED ABOVE. DEBRIS MOISTURE IS BEING 
ADVECTED N-NE ALONG THE NW PERIPHERY OF THE UPPER RIDGE N OF 07N 
BETWEEN 135W AND 113W. VERY DRY UPPER AIR IS EVIDENT ON WATER 
VAPOR SATELLITE IMAGERY N OF 15N E OF 113W. AN UPPER LEVEL 
CYCLONE HAS DEVELOPED OVER 10N105W WITH VERY DRY AIR COVERING 
THE REMAINDER OF THE AREA WITHIN 420-600 NM OF THIS CYCLONE.

SURFACE RIDGING EXTENDS FROM 1024 MB HIGH PRES N OF THE AREA 
NEAR 37N132W TO 18N113W. FRESH NW TO N WINDS ARE EXPECTED TO 
CONTINUE THROUGHOUT THE GULF OF CALIFORNIA DIMINISHING BY 36 
HOURS AS THE PRES GRADIENT RELAXES OVER THE REGION.

A TIGHT PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES 
ASSOCIATED WITH THE ITCZ CONTINUES TO PRODUCE FRESH TRADES FROM 
15N TO 21N W OF 125W AS INDICATED BY A 0218 UTC WINDSAT 
SCATTEROMETER PASS. THESE WINDS WILL PERSIST OVER ROUGHLY THE 
SAME AREA THROUGH 48 HOURS. MEANWHILE FRESH SW FLOW S OF THE 
MONSOON TROUGH WILL CONTINUE OVER THE FAR SE PORTION OF THE AREA 
S OF PANAMA THROUGH 48 HOURS WITH SEAS BUILDING TO 9 FT.

GAP WINDS...A STRONG COLD FRONT WILL MOVE THROUGH THE SW GULF OF 
MEXICO LATER TODAY RESULTING IN A SURGE OF STRONG NORTHERLY 
WINDS WHICH WILL FUNNEL THROUGH THE CHIVELA PASS COMMENCING THIS 
EVENING. THESE WINDS WILL RAPIDLY INCREASE TO GALE FORCE TONIGHT 
CONTINUING THROUGH SAT NIGHT. LOOKING AHEAD...GALE CONDITIONS 
ARE EXPECTED TO DIMINISH BRIEFLY LATE SUN...WITH A RECURRENCE 
MON AS A TIGHT PRES GRADIENT DEVELOPS OVER THE AREA BETWEEN 
STRENGTHENING HIGH PRES OVER INTERIOR MEXICO AND LOWER PRES 
ASSOCIATED WITH THE MONSOON TROUGH.

$$
LEWITSKY