000
AXPZ20 KNHC 121549
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN FEB 12 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...

AN UNUSUALLY STRONG MONSOON TROUGH EXTENDS SW FROM COLOMBIA TO 
02N96W...THEN TURNS NW TO 08N108W...THEN SW TO 02N137W WHERE LOW 
LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W 
TO BEYOND 02N140W. ISOLATED MODERATE AND STRONG CONVECTION IS 
NOTED S OF 06N BETWEEN THE COAST OF S AMERICA AND 91W...AND ALSO 
WITHIN 30 NM EITHER SIDE OF LINES FROM 00N97W TO 06N103W AND 
FROM 02N106W TO 07N113W TO 02N123W.
 
THE LOW LEVEL TROUGH EXTENDS FROM 10N110W TO 16N105W. ISOLATED 
MODERATE CONVECTION IS OBSERVED WITHIN 15 NM EITHER SIDE OF A 
LINE FROM 10N111W TO 18N103W.

...DISCUSSION...

AN UPPER LEVEL SHORTWAVE TROUGH IS SWINGING E ACROSS THE NE 
PORTION OF THE DISCUSSION AREA WITH ITS MEAN AXIS EXTENDING FROM 
32N113W TO 21N118W TO A BASE AT 11N125W. SOME UPPER MOISTURE 
PRECEDES THE TROUGH...AND IS CURRENTLY MOVING E ACROSS THE 
SOUTHERN CONUS BETWEEN EASTERN ARIZONA AND SW GEORGIA WITH THE 
MOISTURE EXTENDING S OVER THE GULF OF MEXICO TO THE N OF 25N.  

AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICAL PACIFIC AT 
05N135W...WITH A RIDGE NW TO 27N145W...THEN THE RIDGE TURNS NE 
TO BEYOND 36N133W. ANOTHER UPPER ANTICYCLONE IS AT 07N75W WITH A 
RIDGE EXTENDING NW ACROSS CENTRAL AMERICA AND THE WESTERN GULF  
OF MEXICO TO A CREST OVER N TEXAS. SOME UPPER MOISTURE IS 
SPILLING E ACROSS THE WESTERN UPPER RIDGE INTO THE DISCUSSION 
AREA TO THE N OF 28N AND W OF 125W. SOME MOISTURE IS ALSO MOVING 
E ACROSS THE RIDGE OVER THE W CENTRAL PORTION FROM 09N TO 20N W 
OF 137W. OTHERWISE THESE UPPER FEATURES COMBINE TO DRY OUT THE 
UPPER LEVELS OF THE SUBTROPICS AND TROPICS N OF THE MONSOON 
TROUGH BETWEEN 112W AND 140W.
        
UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THE EASTERNMOST 
UPPER RIDGE IS ENHANCING THE ISOLATED CONVECTION E OF 100W ALONG 
THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. UPPER DIFFLUENCE 
ALONG THE W PERIPHERY OF THE RIDGE IS SUPPORTING THE CONVECTION 
ASSOCIATED WITH THE LOW LEVEL TROUGH ALSO PREVIOUSLY MENTIONED. 
THE RESULTANT DEBRIS MOISTURE SPREADS NE ACROSS OLD MEXICO TO 
THE S OF 21N...MERGING WITH THE MOISTURE PLUME PREVIOUSLY 
DESCRIBED OVER THE GULF OF MEXICO...WITH THE MOISTURE 
CONCENTRATING INTO A 500 NM WIDE PLUME AND CONTINUING E ACROSS 
FLORIDA AND THE NW BAHAMAS.

ELSEWHERE AT THE LOW LEVELS...A RIDGE EXTENDS FROM 30N140W TO 
22N112W. NORTHERLY WINDS AT 15 TO 20 KT WILL CONTINUE N OF 25N E 
OF THE RIDGE TO THE NORTHERN BAJA CALIFORNIA PENINSULA TODAY... 
BUT DIMINISH BELOW 20 KT TONIGHT. THE GRADIENT WILL TIGHTEN 
AGAIN MON NIGHT INCREASING THE N FLOW TO 20 KT OVER THE WATERS N 
OF 27N E OF 123W...WITH SEAS TO ABOUT 10 FT IN NW SWELL. NE 
TRADES TO THE S OF THE RIDGE CONTINUE AT 20 KT IN THE AREA FROM 
09N TO 23N W OF 130W AND FROM 12N TO 16N BETWEEN 120W AND 
130W...BUT THIS AREA OF ENHANCED TRADES SHOULD SHRINK OVER THE 
NEXT 48 HOURS. LONG PERIOD NW SWELLS ARE MIXING WITH THE NE 
TRADE SWELL OVER THE OPEN WATERS OF ENTIRE DISCUSSION AREA W OF 
95W...AND WILL SPREAD E TO ALONG 93W ON MON. THE COMBINED SEAS 
THAT ARE MAXING AT 11 FT TODAY WILL BUILD TO AGAIN TO ABOUT 13 
FT OVER THE EXTREME NW WATERS ON MON NIGHT.   

...GAP WINDS...
GALE FORCE NORTHERLY WINDS IN AND JUST DOWNSTREAM OF THE GULF OF 
TEHUANTEPEC WILL DIMINISH BELOW GALE LATE TONIGHT AND DIMINISH 
BELOW 20 KT BY MIDDAY ON MON.

FRESH TRADE WINDS IN THE SW CARIBBEAN WILL CONTINUE TO FUNNEL 
THROUGH THE PASSES OF CENTRAL AMERICA INTO AND DOWNWIND OF THE 
GULF OF PAPAGAYO AT 20 TO 25 KT THROUGH MON NIGHT.

NORTHERLY WINDS WILL CONTINUE AT 15 TO 20 KT OVER THE WESTERN 
GULF OF PANAMA THROUGH MON AND INCREASE TO 20 TO 25 KT MON 
NIGHT. 

$$
NELSON