000
AXPZ20 KNHC 192156
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI APR 19 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...
MONSOON TROUGH 05N77W TO 09N89W TO 05N97W TO 07N105W TO 06N110W
THEN ITCZ TO 06N130W TO 04N140W.  SCATTERED MODERATE ISOLATED
STRONG CONVECTION WITHIN 300 NM S OF AXIS E OF 101W AND WITHIN
120 NM OF AXIS 105W TO 116W.

...DISCUSSION... 
UPPER LEVEL CYCLONE AT 27N144W UNABLE TO DENT THE MASSIVE OMEGA
BLOCK CENTERED ON WELL DEFINED ANTICYCLONE AT 15N108W.  NEGATIVE
TILTED TROUGH EXTEND FROM CYCLONE TO 00N120W W OF ANTICYCLONE
WHILE SECOND TROUGH DIGS SW FROM NICARAGUA TO 08N95W.  PLENTY OF
TROPICAL MOISTURE...MAINLY CONVECTIVE DEBRIS FROM ITCZ...ADVECTS
N AND NE AROUND RIDGE CREST WITH LITTLE EFFECTS AS AIR MASS
REMAINS QUITE STABLE.  ON THE E SIDE...SECOND TROUGH PROMOTES
MODERATE DIVERGENT FLOW ALOFT ENHANCING CONVECTION ALONG AND S
OF MONSOON TROUGH E OF 101W.  CONVECTION DECREASING IN LAST FOUR
HOURS MAY INDICATE WEAKENING TROUGH AS RIDGE OVER S AMERICA TRIES
TO EXPAND W.

...ELSEWHERE AT THE LOWER LEVELS...
WEAK SURFACE TROUGH FROM 08N-11N ALONG 124W MOVING AWAY FROM 
UNDER AREA OF DIVERGENCE ALOFT AND IS EXPECTED TO FURTHER WEAKEN
AND BECOME DIFFUSE BY SUN.

LATE SEASON COLD FRONT MOVES THROUGH GULF OF MEXICO FUNNELING 
STRONG N WINDS ACROSS CHIVELAS PASS RESULTING IN GALE FORCE 
WINDS INTO GULF OF TEHUANTEPEC TONIGHT AND EARLY SAT THEN 
DIMINISH TO A MODERATE BREEZE BY SUN.

CURRENT REGION OF 8-9 FT N-NE SWELLS IN WESTERN SIDE OF BASIN
EXPECTED TO DECAY BELOW 8 FT LATE SAT NIGHT. 

MOSTLY DRY AND STABLE CONDITIONS ACROSS REMAINING BASIN POINTS
TO MAINLY DIMINISHING WINDS OVER BOTH GULFS OF CALIFORNIA AND 
TEHUANTEPEC WITHIN NEXT 24 HOURS.  SWELL TRAINS INTRUDING INTO
EPAC W OF 120W FROM N AND W OF 95W FROM THE S EXPECTED TO BECOME
THE ONLY FEATURES IN NEXT 24 HOURS.

...OUTLOOK...
WITH LARGE OMEGA BLOCK IN PLACE AND NOT MOVING...ONLY EXPECTED
WEATHER FEATURE WOULD BE CONVECTIVE ACTIVITY ALONG ITCZ/MONSOON
TROUGH ENHANCED BY UPPER DIVERGENT FLOW.

$$
WALLY BARNES