000
AXPZ20 KNHC 022156
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON JAN 2 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 
2145 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...MONSOON 
TROUGH EXTENDS FROM A 1008 MB LOW PRES CENTER THAT 
INTERMITTENTLY FORMS ALONG THE MONSOON TROUGH NEAR 05N78W AND 
CONTINUES W TO 09N85W...THEN TURNS SW TO 04N97W WHERE LOW LEVEL 
WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W TO 
BEYOND 07N140W. A N-S ORIENTATED TROUGH IS EMBEDDED IN THE ITCZ 
FROM 04N TO 11N ALONG 118W BUT LACKS CONVECTION. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS DISSIPATING IN THE AREA 
FROM 03N TO 07N TO THE E OF 81W. A SMALL CLUSTER OF STRONG 
CONVECTION IS FLARING NEAR 4.5N93.5W. SCATTERED MODERATE 
CONVECTION IS DISSIPATING WITHIN 90 NM EITHER SIDE OF A LINE 
FROM 04N106W TO 09N112W AND IS ALSO NOTED WITHIN 15 NM EITHER 
SIDE OF A LINE FROM 09N131W TO 07N140W.

...DISCUSSION...
A LONG WAVE TROUGH IS APPROACHING THE WESTERN SEABOARD OF N 
AMERICA WITH AN EMBEDDED SHORTWAVE TROUGH EXTENDING FROM 32N128W 
TO 19N140W AND ACCOMPANIED BY A 120 NM WIDE BAND OF VERY DRY 
UPPER AIR. THE ASSOCIATED SURFACE COLD FRONT IS WASHING OUT FROM 
31N126W TO 25N131W. LONG PERIOD NW SWELLS ARE PROPAGATING SE 
ACROSS THE NW PORTION AND ARE MIXING WITH NE SWELL...AND DRIVING 
COMBINED SEA HEIGHTS UP TO ABOUT 18 FT. THESE LARGE SEAS WILL 
SUBSIDE TO ABOUT 11 FT BY THEY TIME THEY REACH THE NORTHERN BAJA 
CALIFORNIA PENINSULA LATE TUE NIGHT.    

AN UPPER ANTICYCLONE IS NEAR 13N108W WITH AN UPPER RIDGE 
EXTENDING N THROUGH 32N114W AND ACROSS WESTERN N AMERICA. 
UPPER DEBRIS MOISTURE IS NOTED WITHIN THE ANTICYCLONIC FLOW. 
SOME THIS MOISTURE IS MOVING OVER CALIFORNIA WHILE ANOTHER 
PLUME CONTINUES E ACROSS CENTRAL OLD MEXICO S OF 25N AND FANNING 
OUT OVER THE SOUTHERN GULF OF MEXICO.   

A SECOND LONGWAVE TROUGH IS MOVING ACROSS EASTERN N AMERICA AND 
CONTINUES S ACROSS THE WESTERN GULF OF MEXICO TO A BASE OVER THE 
TROPICAL PACIFIC NEAR THE GALAPAGOS ISLANDS. THE UPPER LEVELS 
APPEAR VERY DRY S OF 15N E OF 103W.

GULF OF TEHUANTEPEC...
NORTHERLY WINDS HAVE INCREASED TO A STRONG GALE IN THE GULF OF 
TEHUANTEPEC AND EXPECTED TO FURTHER INCREASE TO STORM STRENGTH 
OF 50-55 KT EARLY TONIGHT WITH LATEST GUIDANCE SUGGESTING THESE 
STORM CONDITIONS WILL PERSIST THROUGH LATE TUE NIGHT. THE 
ASSOCIATED SEAS ARE FORECAST TO BUILD TO ABOUT 23 FT WITH N AND 
NE SWELL PROPAGATING S ACROSS THE WATERS N OF 02N BETWEEN 93W 
AND 112W WED.

GULF OF PAPAGAYO...
NE-E WINDS IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO WILL SPREAD 
N TO THE GULF OF FONSECA WED AND INCREASE TO 20-30 KT WITH THE 
STRONGEST WINDS NEAR 09N88W WED. SEAS WILL BUILD TO ABOUT 14 FT 
NEAR 09N89W WED AFTERNOON. NOTE THAT SOME GUIDANCE IS BEGINNING 
TO HINT AT MINIMAL GALE NEAR 9N88W LATE WED AND A GALE WARNING 
COULD BE POSTED ON THE UPCOMING 0430 UTC HIGH SEAS FORECAST.  
      
GULF OF PANAMA...
NW-N WINDS AT 20 KT ARE FUNNELING S ACROSS PANAMA OVER THE 
WATERS N OF 05N BETWEEN 78W AND 81W INCLUDING THE WESTERN GULF 
OF PANAMA. EXPECT THESE N WINDS TO INCREASE TO 20-25 KT TUE 
NIGHT THEN DIMINISH TO 20 KT WED WHILE VEERING TO N-NE.  

$$
NELSON