000
AXPZ20 KNHC 121535
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC WED JUN 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE EXTENDS ALONG 80W N OF 02N ACROSS PANAMA INTO 
THE CARIBBEAN. THE WAVE IS INTERACTING WITH THE MONSOON 
TROUGH...AS NOTED BY A LARGE SWATH OF SW SURFACE FLOW OVER THE 
EASTERN PACIFIC. IN ADDITION AN UPPER TROUGH EXTENDING ACROSS 
THE SW CARIBBEAN IS INTERACTING WITH THE TROPICAL WAVE AND 
MONSOON TROUGH TO ENHANCE MORNING CONVECTION OFF THE COAST OF 
PANAMA...AND DEVELOPING AFTERNOON ACTIVITY OVER THE MOUNTAINS OF 
WESTERN PANAMA AND COSTA RICA. WAVE GROWTH IS SUPPORTED BY FRESH 
TO STRONG E FLOW IN THE MID LEVELS OF THE ATMOSPHERE S OF A  
BOUNDARY LAYER RIDGE WELL N OF THE AREA. THESE FAVORABLE 
CONDITIONS WILL PERSIST THROUGH 48 HOURS AS THE WAVE MOVES INTO 
THE EASTERN PACIFIC TOWARD 90W. LOOKING AHEAD TO FRI AND 
BEYOND...GLOBAL MODELS INDICATE THAT THE WAVE WILL MIGRATE AWAY 
FROM THE DIVERGENT FLOW ALOFT OF THE UPPER TROUGH...AND INTO AN 
AREA OF SUBSIDENT NE FLOW ALOFT ON THE EASTERN PERIPHERY OF AN 
UPPER RIDGE PARKED OVER SOUTHERN MEXICO. THE WAVE WILL DEAMPLIFY 
SLIGHTLY DUE TO DIMINISHING MOISTURE AND A WEAKENING EASTERLY 
JET. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

MONSOON TROUGH ALONG 08N83W TO LOW PRES NEAR 13N112W 1009 MB TO 
09N125W THEN ITCZ AXIS TO BEYOND 07N140W. SCATTERED MODERATE TO  
ISOLATED STRONG WITHIN 90 NM OF COAST OF PANAMA BETWEEN 79W AND 
82W.

...DISCUSSION... AN UPPER CYCLONE IS CENTERED NEAR 22N111W OFF 
SOUTHERN BAJA. UPPER DIVERGENCE ALOFT BETWEEN THIS FEATURE AND 
AN UPPER ANTICYCLONE CENTERED OVER SOUTHERN MEXICO IS SUPPORTING 
A WEAK SURFACE LOW PRES AREA NEAR 13N111W. CONVECTION HAD BEEN 
PRESENT OVERNIGHT IN THIS AREA AROUND THE LOW PRES...BUT HAS 
ALMOST ENTIRELY DIMINISHED FOR NOW. WHILE LOW LEVEL CONVERGENCE 
INTO THE LOW PRES IS MODEST...GIVEN THE UPPER SUPPORT ALONG WITH 
FAIRLY HIGH PRECIPITABLE WATER VALUES SOME RESURGENCE OF 
CONVECTION SEEMS PLAUSIBLE THROUGH TONIGHT AROUND THE LOW PRES. 
THE LOW WILL MIGRATE W THROUGH 48 HOURS INTO LESS FAVORABLE 
AREAS BOTH IN TERMS OF AVAILABLE MOISTURE AND UPPER SUPPORT.

N TO NE SWELL OF 8 TO 10 FT ASSOCIATED WITH WINDS TO GALE FORCE 
OFF THE COAST OF CENTRAL CALIFORNIA ARE PROPAGATING OVER THE 
WATERS N OF 20N W OF 125W...AS NOTED IN A MORNING CRYOSAT 
ALTIMETER PASS.

A LONGWAVE UPPER TROUGH EXTENDS FROM OFF THE OREGON COAST TO 
NEAR 25N135W. THIS IS SUPPORTING A WEAK SURFACE TROUGH SHOWING 
UP IN ASCAT DATA FROM 26N125W TO 23N127W. THE GRADIENT IS FAIRLY 
WEAK BETWEEN THIS TROUGH AND WEAK RIDGING NW OF THE 
AREA...MAINTAINING MODERATE TRADE WINDS ALONG THE ITCZ. 

 
$$
CHRISTENSEN