000
AXPZ20 KNHC 071614
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. SATELLITE WATER VAPOR 
IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE ELSEWHERE WITH ONLY
SCATTERED TO BROKEN LOW CLOUDS AND ISOLATED SHOWERS.

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 WITH WIDELY SCATTERED SHOWERS WITHIN 
120 NM IN THE NW AND 90 NM IN THE SE SEMICIRCLES WILL BE ABSORBED
INTO THE WEAK FRONTAL TROUGH ON THU. THIS FRONTAL TROUGH 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 THIS MORNING CLEARLY
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 BRINGING SEAS OF 8 FT ARE S OF 
05N BETWEEN 97W-112W AND ALSO S OF 06N W OF 112W. THESE SWELLS
WILL CONTINUE TO PROPAGATE N TO ALONG ABOUT 09N BETWEEN 95W-120W
...AND S OF 06N W OF 125W IN 24 HRS. THE SWELL SOURCE ENERGY 
THEN GRADUALLY DISSIPATES LATE THU AND FRI WITH THE ARE OF 
COVERAGE TO BE DEFINED TO THE S OF 08N BETWEEN 95W-120W BY THEN. 
SOME THIS SWELL WILL MIX WITH THE SHORTER PERIOD NE SWELL 
PROPAGATING SW AND W FROM THE GULF OF TEHUANTEPEC GALE EVENT 
RESULTING IN AN AREA OF MIXED NE AND SW SWELL WITH SEAS OF 8-10 
FT THU AND FRI.

$$
AGUIRRE