000
AXPZ20 KNHC 272202
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC SAT APR 27 2013

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 
2100 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 07N74W TO 05.5N78W 
TO 08.5N87W TO 07N98W...WHERE IT TRANSITIONS TO THE 
INTERTROPICAL CONVERGENCE ZONE...CONTINUING ON 06.5N110W TO  
07N118W TO 09N136W TO BEYOND 07N140W. SCATTERED MODERATE TO 
STRONG CONVECTION NOTED WITHIN 210 NM S OF MONSOON TROUGH 
BETWEEN 78W AND 95W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION NOTED WITHIN 150 NM EITHER SIDE OF ITCZ BETWEEN 108W 
AND 134W. 
     
...DISCUSSION...                                            
UPPER LEVEL SOUTHWESTERLY FLOW DOMINATES MOST OF THE DISCUSSION 
AREA N OF 10N W OF 120W...BETWEEN AN ANTICYCLONIC CIRCULATION 
CENTERED NEAR 12N103W AND A PAIR OF UPPER LEVEL LOWS AND 
ASSOCIATED TROUGHING EXTENDING FROM 34N131W TO 28N140W TO A BASE 
NEAR 21N146W. THE UPPER ANTICYCLONE ANCHORS A RIDGE S OF 22N 
THAT SPANS BETWEEN 85W AND 127W. WATER VAPOR IMAGERY INDICATES 
MODERATE TO STRONG DRY AIR AND SUBSIDENCE IN THE VICINITY OF THE 
UPPER LEVEL TROUGH OVER THE NW CORNER OF THE AREA. MOST 
CONVECTIVE PRECIPITATION REMAINS FOCUSED NEAR AND WELL E OF A 
SURFACE TROUGH ANALYZED ALONG 120W FROM 108N TO 14N....WHILE MID 
LEVEL CYCLONIC TURNING IS NOTED IN SATELLITE IMAGERY OCCURRING 
TO THE E OF THE SURFACE TROUGH CENTERED NEAR 10N111W. RECENT GFS 
ANALYSIS INDICATE THAT THE LOW TO MID LEVEL PERTURBATION SEEN IN 
SATELLITE IMAGERY ALONG 111W HAS BEEN IN FAVORABLE ATMOSPHERIC 
CONDITIONS FOR BAROTROPIC GROWTH DURING THE PAST 24 HOURS... 
LEADING TO THE IMPROVED CYCLONIC CIRCULATION. ADDITIONALLY... 
THIS FEATURE IS DIRECTLY UNDERNEATH THE UPPER LEVEL ANTICYCLONE 
ALLOWING FOR OPTIMUM CONVECTIVE OUTFLOW. GLOBAL MODELS FORECAST 
THIS MID LEVEL PERTURBATION TO CONTINUE TO SHIFT W AND WEAKEN 
DURING THE NEXT 24-36 HOURS...WITH ASOCIATED CONVECTION SLOWLY 
WAINING AS WELL.

AT THE SURFACE...A 1031 MB HIGH IS CENTERED WELL NW OF THE AREA 
NEAR 40N141W AND EXTENDS A RIDGE SE TO NEAR THE S TIP OF BAJA 
CALIFORNIA...AND S ACROSS SW PORTIONS OF THE AREA. RECENT ASCAT 
PASSES SHOW FRESH NE TRADES 20-25 KT OCCURRING FROM JUST W OF 
THE SURFACE TROUGH ALONG 120W TO 150W...AND GENERALLY BETWEEN 
10N AND 16N. SEAS IN THIS ZONE ARE RUNNING 7 TO 9 FT IN MERGING 
NE WIND SWELL AND SOUTHERN HEMI SW SWELL. THE WAVE MENTIONED 
ABOVE AND SURFACE TROUGH WILL BOTH MOVE W AND WEAKEN DURING THE 
NEXT COUPLE OF DAYS...WITH THE ZONE OF FRESH TRADES GRADUALLY 
DIMINISHING.
 
FOR THE REMAINDER OF THE EASTERN PACIFIC BASIN E OF 110W... 
RELATIVELY TRANQUIL CONDITIONS ARE NOTED IN OBSERVATIONAL 
DATA...RECENT OVERNIGHT SCATTEROMETER PASSES...AND LATEST GLOBAL 
MODEL DATA. OF NOTE...SW SWELL FROM A SOUTHERN HEMISPHERE LOW 
PRESSURE SYSTEM WILL CONTINUE SPREADING NORTHEASTWARD AND REACH 
THE MEXICAN AND CENTRAL AMERICAN COAST BY EARLY MONDAY WITH WAVE 
PERIODS IN THE RANGE OF 15 TO 17 SECONDS.

$$
STRIPLING