000
AXPZ20 KNHC 071605
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED NOV 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

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

THE MONSOON TROUGH EXTENDS W FROM THE BORDER OF PANAMA AND 
COLOMBIA NEAR 08N78W TO 08N91W TO 08N98W WHERE LOW LEVEL WINDS
TO THE ITCZ TO 08N108W TO 07N125W TO 07N140W. SCATTERED MODERATE 
CONVECTION IS WITHIN 60 NM N OF MONSOON TROUGH BETWEEN 78W-80W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 N OF 
THE ITCZ BETWEEN 113W-115W.

...DISCUSSION...

A NEARLY STATIONARY UPPER CYCLONE IS CENTERED NEAR 27N129W. AN 
ASSOCIATED TROUGH EXTENDS FROM IT SE TO THE DEEP TROPICS AT 
09N124W. TO ITS SE BROAD MID/UPPER LEVEL RIDGING COVERS THE 
AREA...AND EXTENDS WELL TO E OF THE PACIFIC TO THE CARIBBEAN SEA.
A JET STREAM BRANCH SEPARATES THE ANTICYCLONIC FLOW WITH THE 
CYCLONIC TO ITS W AND NW ASSOCIATED WITH THE UPPER CYCLONE...AND 
IS ALONG THE POINTS 17N119W TO 25N114W AND ESE TO OVER WESTERN 
MEXICO AT 24N103W. HIGH LEVEL MOISTURE IN THE FORM OF BROKEN 
HIGH CLOUDS ARE STREAMING NEWD WITHIN ABOUT 250-300 NM EITHER 
SIDE OF THE JET STREAM BRANCH. SMALL CLUSTERS OF SCATTERED 
SHOWERS AND TSTMS CONTINUE UNDER THE AREA OF MID/UPPER 
ANTICYCLONIC FLOW FROM JUST N OF THE
MONSOON TROUGH TO 15N. DIFFLUENCE ALOFT TO THE SW OF THE RIDGE
IS AIDING CONVECTION NEAR AND ALONG THE ITCZ BETWEEN 104W-113W.

THE UPPER LEVEL CYCLONE AT 27N129W IS FORECAST TO BECOME ABSORBED
INTO A LONG WAVE TROUGH CURRENTLY NW AND N OF THE DISCUSSION AREA
THAT WILL PUSH SOUTHEASTWARD ALLOWING FOR A WEAKENING FRONTAL
TROUGH TO CLIP THE FAR NE PORTION OF THE AREA ON THU. A WEAK 
1017 MB LOW AT 30N126.5W WILL DISSIPATE THU AS THE WEAK
FRONTAL TROUGH MERGES WITH IT. THE FRONTAL WILL MARK ADVANCEMENT 
OF STRONG HIGH PRES THAT BUILDS SE ACROSS THE NORTHERN AND 
CENTRAL
WATERS THROUGH THU AND FRI. THE RESULTANT PRES GRADIENT WILL
BRING NW WINDS OF 20-25 KT BEGINNING LATE THU TO THE N OF 28N AND
W OF 131W WITH SEAS TO 9 FT...AND SPREAD S TO N OF 26N W OF 128W
BY FRI WITH SEAS 8-10 FT.

GAP WINDS...THE OSCAT PASS FROM 0638 UTC SHOWED A SWATH OF N-NE
GALE FORCE WINDS THROUGH THE ISTHMUS OF TEHUANTEPEC. THESE WINDS
ARE EXPECTED TO INCREASE 3-40 KT IN 24 HRS WITH SEAS BUILDING TO
14 FT. THE GALE CONDITIONS ARE EXPECTED TO PERSIST THROUGH 
SUNRISE FRI MORNING...THEN DIMINISH. EXPECT NE WINDS TO INCREASE 
TO 15 TO 20 KT TONIGHT IN THE GULF OF PAPAGAYO AND FURTHER 
INCREASE TO 20 TO 25 KT ON WED AFTERNOON. THE RESULTANT NE SWELL 
WILL PROPAGATE W TO ALONG 94W...MERGING WITH THE SWELL 
ORIGINATING FROM THE NORTHERLY WINDS SURGING THROUGH THE GULF OF 
TEHUANTEPEC. 

CROSS EQUATORIAL SOUTHERLY SWELL...RESULTING IN SEAS TO 8 
FT...IS OBSERVED IN THE AREA SW OF LINE FROM 08N140W TO 00N125W. 
THE SOUTHERLY SWELL WILL CONTINUE TO PROPAGATE N TO ALONG ABOUT 
07N EVERYWHERE W OF 97W ON WED...THEN SHRINK TO BETWEEN 95W AND 
118W ON THU. THE SOUTHERLY SWELL WILL MIX WITH THE SHORTER 
PERIOD NE SWELL EMERGING OUT OF THE TEHUANTEPEC GAP WIND EVENT 
RESULTING IN AN AREA OF CONFUSED SEAS FROM 08N TO 14N BETWEEN 
95W AND 115W ON THU. 

$$
AGUIRRE