000
AXPZ20 KNHC 102205
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON DEC 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

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

THE MONSOON TROUGH EXTENDS FROM THE W OF COLOMBIA TO 07N78W TO 
08N93W WHERE IT TRANSITIONS TO THE ITCZ AXIS TO LOW PRES NEAR 
09N101W 1010 MB TO 12N110W TO 11N120W TO 09N130W TO 08N140W. 
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM S OF 
THE MONSOON TROUGH BETWEEN 78W-86W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION WITHIN 180 NM NW QUADRANT OF LOW.

...DISCUSSION...

A LONGWAVE TROUGH EXTENDS FROM NRN PLAINS STATES SW TO CENTRAL
BAJA CALIFORNIA AND SW TO 25N124W TO A SMALL CYCLONIC CIRCULATION
MOVING W AT 26N133W TO A LARGER CYCLONIC CIRCULATION W OF THE 
AREA AT 26N146W. THE TROUGH EXTENSION ACROSS THE N CENTRAL 
PORTION IS IN BETWEEN TWO AREAS OF LARGE DEEP LAYER RIDGING. THE 
FIRST IS TO THE N OF 27N W OF 125W...AND THE SECOND ONE COVERS 
THE AREA S OF THE TROUGH WITH A MEAN RIDGE AXIS ALONG 23N127W 
12N119W TO THE EQUATOR AT 119W. WATER VAPOR IMAGERY SHOWS A 
STRONG SUBTROPICAL JET STREAM BRANCH ENTERING THE DISCUSSION 
AREA THROUGH 20N140W...AND CONTINUING TO 23N124W THEN ROUNDING 
THE BASE OF THE TROUGH TO 21N109W WHERE IT TURNS NE TO ACROSS 
CENTRAL MEXICO AT 22N103W. SATELLITE IMAGERY SHOWS BROKEN CIRRUS 
CLOUDS BEING ADVECTED EWD WITHING 400 NM EITHER SIDE OF THE JET 
STREAM. THE WATER VAPOR IMAGERY ALSO DEPICTS ABUNDANT MODERATE 
TO STRONG SUBSIDENCE ALOFT TO THE S OF THE ITCZ/MONSOON TROUGH 
ZONE RESULTING IN RATHER DRY AND STABLE ATMOSPHERIC CONDITIONS 
THERE WITH ONLY SCATTERED TO BROKEN LOW CLOUDS WITH ISOLATED 
SHOWERS OVER THAT PORTION OF THE AREA.

OVER THE FAR SE PORTION....AN UPPER TROUGH REACHES FROM SE 
MEXICO TO JUST W OF THE CENTRAL AMERICA COASTLINE TO NEAR 
02N86W. SATELLITE IMAGERY INDICATES VERY DRY AIR PRESENT S OF 
09N AND ACROSS THE ENTIRE AREA E OF 100W WITH LIMITED CONVECTION 
PRESENT.

AT THE SURFACE...A STRONG RIDGE DOMINATES THE NW AND N CENTRAL 
PORTIONS WITH AN ASSOCIATED SURFACE HIGH OF 1035 MB WELL N OF 
THE REGION AT 39N142W. THE TIGHT PRES GRADIENT ON ITS SRN 
PERIPHERY DUE TO THE IS PRODUCING NE TO E TRADES OF 20-25 KT 
FROM 15N TO 21N W OF 133W WITH SEAS TO 9 FT. N AREA OF MIXED NE 
AND NW SWELL LEADING TO SEAS OF 8 FT IS EXISTS N OF 10N AND W OF 
A LINE FROM 30N124W TO 10N134W. THE DEEP LAYER RIDGE WILL WEAKEN 
THROUGH 48 HOURS AND SHIFT WEST TO 150W BEGINNING LATER TODAY AS 
A MID/UPPER LEVEL SHORT WAVE TROUGH TROUGH DIGS N OF THE RIDGE 
OVER THE FAR NE PACIFIC. THIS WILL ALLOW THE FRESH TO STRONG 
TRADE WINDS IN THE DISCUSSION WATERS TO DIMINISH.

FRESH TO STRONG WINDS HAVE COMMENCED IN THE NORTHERN GULF OF 
CALIFORNIA INDUCED BY STRONG SURFACE HIGH PRES OVER THE U.S. 
GREAT BASIN AND INVERTED TROUGHING ALONG THE W COAST OF MEXICO. 
THESE WINDS WILL SPREAD SOUTHWARD TO 25N THROUGH TONIGHT...
DIMINISHING TUE AFTERNOON AS THE PRES GRADIENT WEAKENS.

CROSS-EQUATORIAL SE SWELL IS S OF 03N BETWEEN 120W AND 132W. 
THIS SWELL IS ACCOMPANIED BY FRESH TO STRONG E-SE WINDS. THE 
WINDS WILL DIMINISH WITHIN 24 HOURS WHILE THE SWELL PROPAGATES 
TO THE W-NW THROUGH 48 HOURS.

FOR THE GULF OF TEHUANTEPEC...A COLD FRONT WILL MOVE THROUGH THE 
WESTERN GULF OF MEXICO TODAY AND TOMORROW. THE ASSOCIATED 
NORTHERLY WINDS WILL SURGE AT 15-20 KT THROUGH THE CHIVELA PASS 
TUE NIGHT...GRADUALLY INCREASING TO MINIMAL GALE CONDITIONS MID 
WEEK AROUND LATE WED INTO THU. SEAS ARE EXPECTED TO BUILD TO 10 
FT BY LATE WED WITH THIS EVENT.

GULF OF PAPAGAYO...NE WINDS WILL CONTINUE TO PULSE AT 10-15 KT 
WITH AN OCCASIONAL SURGE TO 15-20 KT IN AND DOWNSTREAM OF THE 
GULF OF PAPAGAYO THROUGH THE MIDDLE OF THE WEEK...WITH GUIDANCE 
SUGGESTING AN INCREASE TO 20-25 KT BEGINNING LATE WED NIGHT.

$$
AGUIRRE